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10.3171/2024.7.FOCUS24379_vid
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10.3171/2024.7.FOCUS24379_vid
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Transcript:
Language: EN.
Segment:1 Part 1.
SPEAKER: We are presenting the case of a 43-year-old man who presented with an intracerebral hemorrhage due to a ruptured right posterior medial temporal AVM. Unfortunately, in spite of recommendation of treatment, he was lost to follow-up and presented a year later for treatment. When he presented the second time, he was fully intact. The original imaging studies are shown here. This is a CT scan showing a large temporal lobe hematoma on the right side, and an angiogram at the time showed an anterior choroidal artery AVM, draining deeply into the internal cerebral vein, down to the galenic system with some superficial venous drainage.
SPEAKER: MRI a year later shows the porencephalic cyst area of the previous hemorrhage. The nidus is seen, and there is some supply from the lenticulostriate in addition to the anterior choroidal artery. So the decision making was that this was a Spetzler-Martin grade II with supplementary grade VI AVM. There is a high risk for complications from anterior choroidal artery embolization, and radiosurgery would achieve only a 45% seizure-free status.
SPEAKER: Therefore, in view of all of that, we recommended surgery to go transylvian through a right temporal frontal craniotomy, go through the transinferior circular sulcus approach, and resect the AVM. This is a surgical route seen on an anatomical specimen to indicate the approach. The plan was to identify the anterior choroidal artery from its takeoff from the internal carotid until the inferior choroidal point where it then disappears into the ventricle.
SPEAKER: Then we get through the inferior circular sulcus to the lateral ventricle where we would see it again—the distal end of the anterior choroidal artery. This way, we avoid taking the branches from the external segment of that artery and other branches prior to the inferior choroidal point. At surgery, we can see now that we are splitting the sylvian fissure from distally to proximally very widely because it is important to mobilize the temporal lobe laterally and get all the way down to the origin of the anterior choroidal artery and able to follow it from proximally to distally.
SPEAKER: Sharp dissection is used to split the sylvian fissure. We will pass by the limen insulae down to the carotid cistern. Here is a good view of the supraclinoid carotid and the origin of the anterior choroidal artery. Here is a good view of the anterior choroidal artery supply on its way to the choroidal point.
SPEAKER: Here is an anatomical depiction of that location. The uncus is mobilized posterolaterally. And we have a good view of the posterior cerebral artery. Here, we enter the porencephalic cyst, where the previous hematoma was present as an initial dissection through the insular cortex. We begin coagulating with a nonstick irrigating bipolar.
SPEAKER: The small AVM feeders staying close to the margin of the AVM in spite of its diffuse nature. We are monitoring intraoperative SSEP and MEPs. We here enter the temporal horn of the ventricle and clearly visualize the choroid plexus, which gives us a good demarcation point laterally.
SPEAKER: We proceed around the margin of the AVM anteriorly and detach more feeders. The nidus is becoming better defined the more we dissect it. We now proceed along the medial border of the AVM.
SPEAKER: This is a very clear feeding artery that is taken. And now, as we look deeper on the medial surface, we encounter some small arterial structures. And you can notice the hesitation of not knowing if they are feeders or not. We eventually decide to take them assuming they are feeding the medial deep surface of the AVM.
SPEAKER: Unfortunately, within 5 minutes after this bipolar coagulation, one can see the flattening of the evoked potentials. And we realized immediately that these are lateral lenticulostriates. We proceed with the resection of the nidus of the AVM away from the zone of troublesome coagulation and staying much closer to the nidus wall as can be seen here until the specimen is completely free and taken out.
SPEAKER: There was only a partial return of the evoked potentials, as can be seen here by this point. Postoperatively, unfortunately, the patient had an infarction as can be seen on the diffusion-weighted sequence in the corona radiata and capsular region.
SPEAKER: He was agitated and confused with 2 out of 5 hemiparesis. His mental state improved over several days. The opportunities to improve may be related to the use of interop angiography. After delineation of the AVM, we might have proceeded with resection of the AVM and left the questionable areas alone, as it was unclear if it directly supplied the AVM.
SPEAKER: Intraoperative digital subtraction angiography might have shown complete resection of the AVM, thus providing confirmation that coagulation of the questionable vessels was not necessary. It is unfortunate that the interop navigation was inaccurate in this case. Perhaps interop ultrasound may have helped. Certainly, a reminder constantly of the normal anatomy is important.
Segment:2 Part 2.
SPEAKER: This case involves surgically induced venous sinus thrombosis. This case involves surgically induced venous sinus thrombosis. The clinical presentation is a 66-year-old woman, who presented with progressive confusion, gait difficulties, and right-sided hearing loss. Her MRI showed a large right-sided Koos grade IV vestibular schwannoma with an element of hydrocephalus. Here you can see the MRI. The rationale for treatment is that she was becoming increasingly symptomatic with her large tumor.
SPEAKER: The risks of removal of the tumor included hemorrhage, ischemic stroke, new cranial nerve deficit, aside from her hearing loss and infection. Anticipated problems were that she may require a VP shunt in addition to tumor resection. Our plan was to assess her following resection and see if she required a shunt. The chosen plan was retrosigmoid resection of a Koos grade IV vestibular schwannoma.
SPEAKER: We did consider a translabyrinthine approach, but chose a retrosigmoid approach in this particular case, for the reason that the corridor of the tumor was already present with the location of the arachnoid cysts posterior to the tumor. But we do in fact do more cases translabyrinthine than retrosigmoid. We proceeded with the tumor resection, and the postoperative details will be described.
SPEAKER: We exposed the retrosigmoid region and performed a craniectomy in this region. We opened the dura in a cruciate fashion. And you can see the sigmoid transverse junction was exposed. We placed one cut to the transverse sigmoid junction and another cut to end at the inferior aspect of the sigmoid. The flaps are placed, as shown here, where there's a superior flap at the transverse sinus and a lateral flap at the sigmoid sinus.
SPEAKER: This exposed the sinus over a length. In this particular case, it may have been helpful to cover the transverse sinus and the sigmoid junction where it was exposed perhaps with a moist cottonoid. This was not performed. The question would arise whether a translab approach would increase or decrease the chance of a clot. But we've certainly experienced thrombosis of the sigmoid sinus with the translab approach as well.
SPEAKER: The tumor is exposed, and we perform a resection of the capsule and then use an ultrasonic aspirator to progressively debulk the tumor. Here you see dissection of the inferior part of the tumor from the lower cranial nerves and identification of the brain stem.
SPEAKER: We identified the eighth nerve and ligate and divide this. And we proceed with our dissection and debulking of the tumor and removal of the capsule. Here is an extracapsular dissection, and we'll remove a large portion of the capsule that does not involve the facial nerve. And we now identify the facial nerve at the brain stem and follow this up toward the internal auditory canal. Here we identify the internal auditory canal and then proceed with drilling of the IAC.
SPEAKER: We cauterized the dura up to the region of the endolymphatic sac and drill out the posterior lip of the internal auditory canal. After adequate exposure of the canal, we open up the dura over the region of the tumor and continue debulking of the tumor from the internal auditory canal.
SPEAKER: We remove all the tumor within the canal and then progressively remove the tumor at the lip of the porus acusticus. But we find a very adherent aspect of tumor just at the lip of the porus acusticus. So we do a subtotal resection and thin this carpet of tumor. We then place fat in the IAC to forestall CSF leak and then proceed with closure. Please note the desiccation of the dura overlying the sigmoid sinus here.
SPEAKER: The dura was closed in an interrupted fashion using NURULON suture, and a cranioplasty with MEDPOR was used to cover the defect. The scalp was closed. Her postop day 1 scan shows no complications, with the exception of a thrombosed sigmoid and transverse sinus on the ipsilateral side. We felt this was a consequence of having an exposed and desiccated sinus and also perhaps suturing and injuring the sinus with a suturing when closed.
SPEAKER: At this time, she was continuing to be hydrated postoperatively and we did add daily aspirin. Postoperative day 4, we noticed increasing edema in the cerebellar peduncle and an impending venous infarction in this area. So she was anticoagulated with a heparin drip, and this was started with a slow start of anticoagulation to ramp up to full anticoagulation over several hours.
SPEAKER: On postop day 5, she had an acute neurological decline. She became relatively comatose in a rapid period of time, and an emergency CT scan here demonstrates a hematoma within the resection cavity and involving the area of venous infarction. She had acute hydrocephalus associated with this. She was taken to the operating room and the hematoma was evacuated, and a ventriculostomy was placed.
SPEAKER: Subsequently, she had an extensive ICU course with CSF drainage and was ultimately sent to rehab after several weeks. She required a permanent VP shunt for hydrocephalus and she was left with permanent neurological deficit from this hematoma. And she has unsteady gait and she has increased facial nerve weakness. We presume that the facial nerve deterioration was a result of the hematoma and increasing trauma to the facial nerve.
SPEAKER: She was a House-Brackmann II immediately after surgery, and she went to a House-Brackmann IV. Here's the delayed postop scan at day 60, and you can see the extensive venous infarction in the cerebellar peduncle and the VP shunt placed for hydrocephalus. The radiographic outcome demonstrates that the tumor was resected, but there was extensive venous infarction of the peduncle and hydrocephalus.
SPEAKER: Analysis of the complication: We believe that there was no error in diagnosis or risk anticipation in this case. The flaw was in the execution of the treatment plan, which was thrombosis of the venous sinuses adjacent to the operative site. This is a routine approach, and it was due to desiccation of the dura and injury of the sinus with exposure and using sutures that were woven to close the dura adjacent to the sinus resulting in thrombosis of the sinus.
SPEAKER: Subsequently, with the developing impending venous infarction, she was anticoagulated which promoted hemorrhage into this region. The question has arisen as to whether anticoagulation was indicated in this case. It has been our practice to not treat incidental thrombosis of sinuses if it is not a dominant sinus. However, given the fact that she was developing increasing edema and the evidence of a venous infarction, we chose to anticoagulate.
SPEAKER: The literature would support this treatment paradigm. What did this teach us? The technical improvement is to avoid injury and limit exposure to the venous sinuses during opening. This is a routine operation and all sinus repair should be performed with vascular sutures, not woven sutures, to avoid induction of thrombosis. This includes closing the dura adjacent to the sinus. More recognition of the potential for venous injury and its consequences during a routine exposure is important.
SPEAKER: This case is interesting insofar as the venous sinus was not dominant on this side, but was still very important because a large draining vein affecting the cerebellar peduncle was involved and became thrombosed with injury to the sinus. Thus, one may not appreciate the consequences of sacrifice of a sinus that is not dominant.
Segment:3 Part 3.
SPEAKER: The patient in this case was a 75-year-old man presenting with gait disturbance and frequent falls because of it.
SPEAKER: When he started to get headaches, an investigation was done. His neurological examination was unremarkable except for unsteady gait. His MRI showed a large petrochemical meningioma extending from the chiasmatic cistern down to just inferior to the level of the internal acoustic canal. Brainstem compression was significant, which accounted for his symptoms.
SPEAKER: There was also brainstem edema, but no hydrocephalus that would account for the wobbly gait. One unusual aspect of this tumor was the position of the basilar artery, which is denoted by the red dot here. Most petroclival meningiomas pushed the basilar artery to the opposite side. This one completely surrounded the artery, which meant that the perforators that supply the brainstem were entirely within the tumor.
SPEAKER: Surgical intervention was indicated because the patient was still relatively healthy. And his symptoms were not only debilitating, but likely to progress rapidly. Brainstem decompression was a rational goal. The major risks to the basilar artery and its perforators were noted before surgery. The entire surgical team was well aware of the danger of hurting these small perforators.
SPEAKER: Because the tumor extended superiorly beyond the dorsum sellae, a posterior petrosectomy was deemed suboptimal and an anterior petrosectomy approach with drilling of the Kawase quadrilateral was considered the best option because it would expose the whole area of the tumor from superior to inferior. And since the right side was involved, the dominant temporal lobe would be spared any risk.
SPEAKER: The drilling of the anterior petrosectomy proceeded in standard fashion. The posterior fossa and middle fossa dura were opened perpendicular to each other, and the superior petrosal sinus, along with the tentorium, were coagulated and then cut. As we neared the incisura, we discovered that the fourth nerve was hopelessly engulfed by the tumor.
SPEAKER: Painstaking dissection revealed the posterior cerebral artery. And with some debulking, the superior cerebellar artery was also found. Both of these were significantly adherent to the tumor. Interpreting this as a personal challenge for one's skill is a bad idea. Debulking laterally and anteriorly were without difficulty, but working on the brain stem side, we encountered these perforators.
SPEAKER: And eliminating them as blood supply simply to the tumor was also a bad idea. These are brain stem perforators. The basilar artery was visualized. And again, working lateral and anterior to it proceeded smoothly. But trying to dissect the tumor between the basilar artery and brain stem was a different story.
SPEAKER: At the base of your screen is the brain stem, and the tumor was attached to the pia firmly, which indicated infiltration. Working more between the basilar artery and brainstem, we encountered bleeding from small arteries like this. This should have been interpreted as a signal to stop working in this area, but yet the decision was to move forward aggressively.
SPEAKER: For this, these tiny arteries cemented by the tumor stood no chance. Here is one more of those small perforators, and it should have been left alone along with the tumor that surrounded it.
SPEAKER: After reaching the inferior limit of the exposure at the level of the IAC, we worked back up the basilar artery. Portion of the tumor under the trigeminal nerve was the last to be removed. And with that, we have the full view of the surgical field here. The cottonoid estimates the extent of the exposure. Postoperative MRI showed a minimal residual tumor in the area where we worked, but there was massive edema of the brainstem.
SPEAKER: DWI indicated ischemia from the midbrain down to the pons. The patient remained in a coma after surgery. After several weeks without improvement, the family decided to transition to comfort care, and the patient expired. Whereas the plan for decompression of the brainstem was sound, the brainstem edema should have been interpreted as pial invasion by the tumor and blood supply from the basilar perforators.
SPEAKER: This, in turn, should have made the surgical strategy more conservative. Since the meningioma completely engulfed the basilar artery, a total or even near-total resection was simply not possible. The perforators have to travel through the tumor to reach their target, that is, the brainstem. The path might be direct, but it could also be very circuitous.
SPEAKER: As soon as the perforators were encountered, the notion of stopping must be entertained. It's very tempting to try to dissect the perforator from the tumor. But this is a bad idea. You might get lucky with the first one. But with the next one, you might not. And bleeding from these tiny vessels can only be stopped with coagulation, which, as we can see, leads to poor outcome.
SPEAKER: As such, the configuration of the perforators determines how much residual you must leave behind. The specific lessons to be learned are for better interpretation of brainstem edema with a high level of caution to be less aggressive. And once perforators are encountered, you must stop. Taking more tumor toward the brainstem can lead to catastrophic outcome. Extensive monitoring might have stopped the injury to multiple perforators, but signal changes from even a single perforator injury could prove devastating to the patient.
SPEAKER: This complication illustrates that despite clear articulation of the surgical goal and understanding of risky areas, it is still possible to lose track of those once the operation starts. Even as one focuses on resection of the tumor as the task at hand, one cannot lose track of the surgical goal and risk assessments.
Segment:4 Part 4.
SPEAKER: This is the case of a 32-year-old female, who presented with visual field deficits corresponding to a left-sided clinoidal meningioma.
SPEAKER: Due to the progressive nature of the deficits, left-sided pterional craniotomy was undertaken to remove the tumor and decompress the optic nerve. The exam in this case was only positive for decreased visual acuity and narrowed visual field in the left eye. MRI examination axial T1 with contrast image demonstrates the meningioma that is somewhat en plaque around the area of the clinoid with evidence of crinoidal hypertrophy and hyperostosis, as well as evidence of tumor encasing the nerve into the optic canal.
SPEAKER: The treatment was necessary due to the progressive nature of the visual field deficits and the risks included injury to the optic nerve and other potential vascular complications. Due to the extension of the meningioma to the optic canal, an extradural clinoidectomy was contemplated and conducted as the first phase of the operation before the dura was opened and after the craniotomy was completed.
SPEAKER: This would allow the decompression of the optic nerve early on, and this would minimize the chance of traction injury to the optic nerve during manipulations related to intradural tumor removal. The plan was to open the dura after the clinoidectomy and remove the tumor inside the canal by opening the falciform ligament and also being able to remove additional tumor in the region.
SPEAKER: The clinical scenario in this case, as it unfolded, was that during drilling and hollowing out the clinoid process, the operator was very focused on the protection of the optic nerves and suffered from cognitive tunneling and did not pay adequate attention to the other structures underlying the clinoid, including the carotid artery.
SPEAKER: In addition, the operator pressed on the drill significantly to make sure the bone is removed. And this maneuver led to the injury of the carotid artery and significant bleeding. This is the video of the procedure. Again, a left-sided pterional craniotomy. The optic canal was unroofed.
SPEAKER: The clinoid is being hollowed out. As you can see, the operator is pushing on the drill without any off and on episodic relaxation to have more proprioceptive feedback on where he or she is drilling. As the bleeding was encountered, we were unable to conduct a primary repair. Therefore, a piece of cotton soaked in thrombin was used to create a tamponade in the region and to keep the tamponade in place after the bleeding was stopped, and hemostasis was reached.
SPEAKER: The dura was opened and then tacked to the area of the pericranium to almost externalize this area from the internal space and keep pressure on the piece of cotton. This maneuver was very effective. Intradural decompression of the nerve and opening of the falciform ligament and removal of the tumor within the optic canal was conducted effectively, and this patient did not suffer from any untoward effects.
SPEAKER: A gross-total resection was achieved. The patient had an unremarkable recovery. Postoperative CT angiogram was unremarkable, and the 3-month angiogram, as you can see here, demonstrated no evidence of pseudoaneurysm formation. Analysis of this complication demonstrated the concept of cognitive tunneling—that the individual surgeon in this case suffered from some sort of blindness, albeit unintentional.
SPEAKER: And this can occur during surgery when the surgeon is so focused on a specific task at hand that he or she inattentively neglects other stimuli or relevant information in the surgical field. The operator should press the drill against the bone in a controlled fashion and in short episodes while considering all structures at risk.
SPEAKER: The use of a coarse diamond drill bit could have contributed to this injury. The specific lesson learned is that less is more. Performance of a direct repair or bypass may not be needed in many occasions, as small vascular injuries can be managed effectively via small piece of cotton and gentle tamponade. Pseudoaneurysm formation is not universal, and drilling should be conducted in a gentle and dynamic off-and-on maneuver rather than a more forceful, continuous activity to allow for more effective proprioceptive feedback against the bone.
SPEAKER:
Segment:5 Part 5 .
SPEAKER: This young man in his mid 20s had a hemorrhage from this lesion in the cervical spinal cord, which resulted in temporary quadriplegia. Over time, he made a very good recovery. The therapeutic assessment was as follows. After one episode of quadriplegia, the patient was presented with options, and he, with the support of his mother, was eager to proceed with treatment.
SPEAKER: And after reviewing the studies, we considered him to be a very good surgical candidate with a high likelihood of a successful outcome. The patient and his mother were fully aware of the associated risks and alternative treatments and elected to proceed with surgery. The plan for treatment was embolization of the arteriovenous malformation, resection of the AVM through C4-6 laminoplasty.
SPEAKER: On the MRI scan, we see the involvement of the AVM in the spinal cord and the effects of the previous hemorrhage with edema around the lesion. We also noticed that the arteriovenous malformation is not in the midline but off to the side, making it much more accessible for surgical intervention. An angiogram demonstrates the spinal arterial venous malformation, which was embolized as much as possible.
SPEAKER: After embolization, the patient was brought to the operating room, where through a laminoplasty, the arteriovenous malformation was exposed. And using bipolar coagulation, it was separated from the spinal cord. Even though we are aware that there is AVM inside the spinal cord, experience has taught us that we could resect and go through the AVM, obliterating the components that went into the spinal cord and then removing the portion of the AVM that was in the lateral gutter.
SPEAKER: We see the Onyx down low, the black filled portion of the arteriovenous malformation. Through this posterolateral approach, we had good access to the lesion and resected it uneventfully. During this time, monitoring remained unchanged, and that included sensory as well as motor evoked. With the resection of the AVM, monitoring was discontinued, and the laminoplasty replaced in the usual fashion.
SPEAKER: The patient was taken directly to the angio suite, where complete excision of the AVM was demonstrated. With the patient returned to the recovery room, it was apparent that he had quadriplegia. This completely unexpected exam led to the patient being taken emergently to the CT scanner, where the following CT scan demonstrated compression of the spinal cord with the laminoplasty.
SPEAKER: The patient was rushed back to the operating room where the compression was removed. Following the surgery, the patient had a severe motor deficit with quadriplegia and severe sensory deficit. He was, after several days, turned over to rehabilitation, where over the following 10 days, he recovered significant sensation but no significant motor function.
SPEAKER: He returned to his home country for further physical therapy. A 10-month follow-up, we received the following information from him where he says, quote, "I'm doing great. Just finished my occupational and physical therapy. Currently, I'm able to stand and walk using a walker. However, temperature and pain sensation is still nonexistent. Still, I'm content with my recovery," unquote.
SPEAKER: To me, this is as bad of a complication as we can possibly have, as it is one that can be completely avoided. We learned from this a number of points. One is to make triple certain that the laminoplasty is appropriately secured; to continue monitoring even during closure of the evoked potentials, sensory and motor; and returning the patient immediately to the operating room instead of getting a stat CT scan, since the only causes that are remedial are compression, either from the laminoplasty or more likely from a hematoma, and a stroke, which surgery would not help and which would be very, very unlikely.
SPEAKER: And since time is so important, this is a critical point. We further developed some spacers for laminoplasty, so that the cut from the saw can be compensated. But these are not commercially available. This case greatly emphasizes that there is no portion of the surgery that does not have a potential for a serious complication.
SPEAKER: This particular complication rests on my conscience to this day.
Segment:6 Part 6 .
SPEAKER: We are describing the case of an 80-year-old female who was quite disabled by bad hemifacial spasm on the left side, not helped by Botox.
SPEAKER: She was otherwise intact. The MRI shows dolichoectatic left vertebral artery compressing the exit zone of the facial nerve. We discussed the treatment and the rationale for it. We proposed retrosigmoid craniotomy to use a sling clip technique to elevate the vertebral artery of the exit zone. This is a quite well known technique because the Teflon felts are insufficient in relieving spasm from large vertebral artery.
SPEAKER: Here at surgery, one can see the use of the NIM stimulator to identify the origin of the facial nerve. The tortuous vertebral artery is well seen anterior to cranial nerves 9 and 10. And here it is lifted with the sucker off the exit zone of the seventh nerve.
SPEAKER: In order to keep it in a position that is away from the facial nerve, we are using this Gore-Tex sling, which we fashioned with an appropriate width to fit around the vertebral artery. We are anchoring one end of it to the petrous dura with a 5-0 Prolene suture. We then used the other end to elevate the vertebral artery.
SPEAKER: However, we are very cautious of that perforator that can be seen along the sucker. It appears that the edge of the Gore-Tex will kink it. So we are cutting a window into the Gore-Tex to allow passage of the perforator before finalizing the position. We are trying again, suspending the vertebral artery anterolaterally and watching the perforator.
SPEAKER: We then put an aneurysm clip to hold the sling in this exact position. And we inspect the perforator again, but we are not confident that it is patent. We released the construct and decide to do it again with a narrower piece of Gore-Tex, which we are fashioning here.
SPEAKER: By bypassing it around the vertebral artery, we now are farther away from the perforator. But this time, because we don't want the Gore-Tex sling to slip toward the perforator while we are suspending it, we will reverse the steps by placing an aneurysm clip on the Gore-Tex sling in the exact position that we want it. And then we will suspend it.
SPEAKER: We can see that the perforator is quite clearly unencumbered by the sling. And we are very satisfied with this position. Now, to suspend it to the petrous dura, it would have been awkward to use a Prolene. So we are making a small slit in the petrous dura big enough to allow the passage of one blade of an aneurysm clip.
SPEAKER: And then we will hold the dura and double sling with the permanent aneurysm clip as shown here. We now are inspecting everything. And we realize that there is an AICA branch that is also compressing the facial nerve. First, we place Teflon felt between the vertebral artery and the exit zone.
SPEAKER: And then we lift the AICA to place Teflon felt between it and the exit zone as well since we cannot be sure which of the two arteries is the more offending agent. Here are triangular pieces of Teflon felt going between the AICA and the brain stem.
SPEAKER: Further inspection, more proximally on the vertebral artery, indicates that we might want to add another bridge of Teflon just to be absolutely certain that the entire course of the vertebral artery has been redirected away from the facial nerve and its exit zone.
SPEAKER: One can see the hypoglossal nerve draped on the vertebral artery to the left of the piece of Teflon. The lateral spread potential disappeared at this point, indicating good decompression. We add a Ligaclip to the free ends of the sling for added security. And we complete the closure.
SPEAKER: A postop CTA indicates the new position of the vertebral artery, and the clips can be clearly seen. Postoperatively, she had a left House-Brackmann grade III, left anacusis ataxia, unable to ambulate. The facial weakness worsened at 6 weeks to a grade VI. At 4 months, she was still having significant difficulty walking. The complication is clearly a small brainstem infarction from occlusion of a brainstem perforator.
SPEAKER: One could have been even more meticulous with the perforator in spite of our best efforts. Perhaps we should have used ICG videography. Even though we actually use it quite routinely in similar cases, it is possible that the perforator may have been kinked even after the closure, while it looked quite preserved during the surgery. One will remember that CSF and brain shifts do occur after closure of a craniotomy, and the patient is mobilized.
SPEAKER: The sling clip technique is useful in cases of compression caused by large arteries such as basilar artery or vertebral artery. With simple MVD, placing Teflon felt between the offending vessel and the nerve may not be sufficient. Had there been no possibility to save the perforator, other configurations of Teflon could have been considered.
Segment:7 Part 7.
SPEAKER: other configurations of Teflon could have been considered.
SPEAKER: other configurations of Teflon could have been considered. The patient was in his late teens. He had multiple family members with prior aneurysmal subarachnoid hemorrhage. Here is his angiogram, which shows a 7-mm fusiform aneurysm of the distal p1 and p2 segments of the right PICA. Of note, there is a branch coming off the side of this dolichoectatic aneurysm. The patient's strong family history of aneurysmal subarachnoid hemorrhage prompted treatment, as well as did his young age and the opportunity for a cure.
SPEAKER: Risks and benefits of the surgery are listed here. Far lateral craniotomy, dissection into the cisterna magna to expose the V4, PICA, the aneurysm, and its branches; aneurysm trapping and excision; first, an end-to-end reanastomosis of the PICA trunk to the PICA origin.; second, an end-to-side reimplantation of the p2 PICA branch to the distal PICA trunk. First, the aneurysm was trapped between temporary aneurysm clips.
SPEAKER: Here, I'm transecting the proximal end of the aneurysm and freeing the aneurysm for its resection. Inspecting this proximal stump reveals that there is still pathology in the arterial wall here. There's thickness of the artery and pathologic appearance. And so I excised that as well. I'm all the way to the V4 segment here, and I still am concerned about the amount of pathology in that stump.
SPEAKER: I've readjusted my clips now, placing them on the vertebral artery. This allows some additional PICA to be resected all the way back to the origin at the V4 segment. Here, the main trunk of PICA is brought together with this first stitch to the stump of PICA. Now a running continuous suture line was placed to complete the first half of the anastomosis. The artery was rotated slightly.
SPEAKER: And the second wall of the anastomosis could be completed again with running continuous suture. And initially, the bypass was patent. Now, the second efferent branch from the aneurysm was prepared for reimplantation to the PICA trunk. Here, the toe stitch is being placed, and now the suture can be run along the first suture line. Here, the second suture line is being sewn, and this completes the anastomosis.
SPEAKER: As the temporary clips are removed and hemostasis is achieved, we can see that this graft is nicely patent. However, inspection of the initial end-to-end reanastomosis reveals that the first bypass has occluded. Doppler flow probes demonstrate that the end-to-end reanastomosis is not flowing. And disruption of platelets with my bipolars does not succeed in keeping this patent.
SPEAKER: Therefore, this reanastomotic bypass is taken down. I coagulated the connection of the stump. And I'm transecting the trunk free. As we inspect the lumen of the PICA trunk, you can see that the platelet plug is very dense and very adherent. It was impossible for me to clear the lumen and use this for the anastomosis. Fortunately, the distal PICA could be mobilized upward.
SPEAKER: And unfortunately, the medullary perforators tethered the more proximal portion of PICA. Therefore, I decided to do a side-to-side reimplantation. Here, the arteriotomy is made in the vertebral artery. Next, an arteriotomy is made in the distal p2 segment. This first stitch approximates the PICA to the V4, and now I'm doing this side-to-side anastomosis, bringing the two inner layers of the walls together. And now I am sewing the second two layers over the top to complete the side-to-side in situ anastomosis.
SPEAKER: As the clip comes off of the V4 segments, we now have flow in the bypass, and IC green video angiography confirms patency of the reimplantation site. Now the PICA trunk fills off of this side-to-side anastomosis, and the second reimplanted branch fills off of that main PICA trunk. The patient tolerated the procedure well. He had no new neurological deficits.
SPEAKER: Here is his postoperative angiogram, which shows that the side-to-side reimplantation of PICA is nicely patent, as is the more distal reimplantation of the PICA branch. The 3D angiogram to the right nicely shows these two reimplantation techniques. This animation shows a fusiform dolichoectatic aneurysm arising from the distal PICA with two outflow arteries.
SPEAKER: The aneurysm is completely trapped here with temporary aneurysm clips, and the aneurysm is excised. The primary PICA vessel is brought together with an end-to-end reanastomosis, and the secondary branch is reimplanted. The end-to-end reanastomosis subsequently thrombosed, requiring revision. The distal artery was then freed, swung to the V4 segment of the vertebral artery, and reimplanted with a side-to-side anastomosis.
SPEAKER: This case gives us opportunities for improvement. There was no error in diagnosis, perhaps some risk anticipation that was lower than expected. But the treatment plan was a good one. The flaw was in the execution. The aneurysm needed to be excised. But always with aneurysm excision is the concern that too much resection of tissue would leave a large gap that could not be bridged by the reanastomosis with an end-to-end construct.
SPEAKER: In this case, I left a little bit of pathologic tissue on the ends and incorporated that into the end-to-end reanastomosis, which ultimately led to the bypass occlusion. The opportunity for improvement would have been to excise further back to completely normal tissue and execute the end-to-end anastomosis with healthy tissue. Another specific lesson that this case teaches us is that unanticipated things happen.
SPEAKER: And we have to be ready to take that next step to that next level to get through the complication. In this case, I needed to take down a previously done anastomosis and redo it with an equally complicated side-to-side reanastomosis to the vertebral artery. This required an escalation in skill and also in the complexity of the construct, but teaches us that we have to be ready and adaptable to make that transition in response to the adverse events.
SPEAKER: This case also teaches us that there is room for innovation, particularly in bypass surgery. This was a bypass that I had never done before. And circumstances dictated that I do something unique here. The side-to-side reimplantation of PICA onto the vertebral artery is a unique construct. And it's these innovations under duress that make them even more special. Thank you.
SPEAKER:
Segment:8 Part 8.
SPEAKER: The patient presented as a 57-year-old woman with a 6-month history of progressive visual loss in the right eye. No headaches, normal left eye visual acuity. Her examination showed 4 mm of right-sided proptosis, a relevant afferent pupillary defect in the right eye, reduced color vision in the right eye, and best corrected visual acuity 20/50 in the right eye.
SPEAKER: This is the CT scan demonstrating the typical features of hyperostosis of the greater wing of the sphenoid lateral portion of the orbit and roof of the orbit. The MR shows the limited intradural component of the meningioma, as well as involvement of the greater sphenoid wing and the posterolateral periorbital. The patient was symptomatic for her declining vision, and in this therapeutic assessment, she also had objective evidence of optic nerve dysfunction.
SPEAKER: Her case was presented at our multidisciplinary skull-base tumor board, and she was recommended to decompression in combination with oculoplastic surgery, along with orbital reconstruction. Risk assessment related to the risks of general anesthesia, including pneumonia, bladder infection, postoperative venous thrombosis, and sudden death, as well as specific to the surgical approach, including wound infection, postoperative hematoma, double vision and worsening vision, and CSF leak.
SPEAKER: The chosen plan was a combined frontotemporal orbital zygomatic approach for removal of tumor-involved bone, intradural tumor with a pericranial graft, followed by removal of tumor-involved periorbita and orbital reconstruction. The procedure was done in combination with oculoplastic surgery, and the operative plan and setup included exposure of the entire face to the upper lip, so that the position of the eye could be examined after reconstruction.
SPEAKER: Standard surgical approach, coronal incision, removal of tumor involved bone and intradural tumor first, and then removal of intraorbital tumor with reconstruction using a porous polyethylene implant with embedded titanium mesh. The clinical scenario was that the operation was performed as described. Orbital roof and lateral wall were removed to the boundaries of the superior and inferior orbital fissures.
SPEAKER: The optic canal was exposed and drilled with a 2-mm diamond drill bit with copious irrigation using the operating room microscope. The intradural tumor was then resected and the dura repaired, and then the lateral tumor-involved periorbital resection was performed by oculoplastics and the periorbital defect covered by a small absorbable sponge. And the position of the globe checked versus the operative side.
SPEAKER: And then the wound closed. We performed a two-piece orbital zygomatic craniotomy with image guidance to confirm our position. The tumor involved orbit was removed. This is the orbital implant shown by a yellow arrow and the grafted convexity dura. On postoperative day 1, the patient complained of binocular, horizontal double vision. And examination demonstrated an inability to adduct the right eye beyond the midline.
SPEAKER: Forced duction under local anesthesia confirmed mechanical restriction of adduction, and a CT scan demonstrated impingement of lateral rectus by sharp edge of the zygomatic bone and inward curvature of the orbital implant, which may also affect muscle vector and function. These are examples of the postoperative CT on the top with the small arrow indicating impingement.
SPEAKER: Examples of the patient's attempt at left gaze with restricted adduction and then the confirmation of impingement with the force duction under local anesthesia. On postoperative day 2, the patient was returned to the operating room. The bony impingement was removed, And a Silastic sheet was placed between the lateral orbital and the orbital implant, and a force duction test confirming the patient had normal excursion of the right eye, seen on the bottom images.
SPEAKER: Here's the radiographic outcome confirming removal of all intradural tumor and near-total resection of intraorbital tumor, and then the CT scan demonstrated as previously described. The patient's proptosis was improved postoperatively. Analysis of the complication, opportunities for improvement: There was no error in diagnosis or treatment plan, but an opportunity was missed to prevent the observed complication.
SPEAKER: The better plan would have been to perform a forced duction test of the right eye after reconstruction at the first operation. Subsequently, this plan became part of the comprehensive plan, and thereafter, there were no cases of restricted strabismus observed. The forced duction test is a common evaluation for eye muscle entrapment. The limbus of the eye at the junction of the cornea and sclera is grasped with forceps, and the eye is moved in various directions to detect tethering: superiorly for inferior rectus tethering, inferiorly for superior rectus, medially for lateral rectus, and laterally for medial rectus, and down and medially for superior oblique.
SPEAKER: This maneuver assesses whether there is a structural abnormality in one of the four walls of the orbit impinging on eye muscle and restricting active eye movement. What did this teach us? Intellectually, there was a knowledge gap in that the risk for mechanical impingement was underestimated or not strongly considered. Technical execution: the observed event resulted in a change in our routine operative plan at the end of the procedure before replacing the cranial bone flap, in that a forced duction test had to be completed by the oculoplastic surgeon as the final step in the assessment of the orbital reconstruction.
SPEAKER: We continue to practice orbital reconstruction and perform in all cases in combination with our oculoplastic surgery colleagues.
Segment:9 Part 9.
SPEAKER: We present a 55-year-old woman with nonfunctioning pituitary macroadenoma, who underwent subtotal resection one year prior at an outside hospital. This initial MRI shows a large enhancing sellar lesion with suprasellar extension and displacement of the optic chiasm.
SPEAKER: After her first surgery, a residual tumor remained. A redo transsphenoidal resection was attempted. But due to significant scar tissue and fibrous, residual tumor persisted. Due to the persistence of her visual symptoms and unlikely resolution without further intervention, additional surgery was discussed.
SPEAKER: A transcranial approach was advised to resect the remaining tumor. In the following slide, our operative video demonstrates the transcranial approach using a right lateral supraorbital craniotomy for sellar and suprasellar tumor resection. During the surgery, the contralateral internal carotid artery suffered injury from the ultrasonic aspirator requiring repair.
SPEAKER: After performing the craniotomy, we opened the dura using a 15 blade. We placed an adapted patty over the cortex. The surgical corridor is followed to the ipsilateral optic nerve.
SPEAKER: The arachnoid is opened with microscissors. Hemostasis of the capsule is performed with bipolar. The ultrasonic aspirator is brought into the field to begin tumor resection.
SPEAKER: At this point, we note brisk arterial blood flow. Two sections are then brought into the field for better visualization. The source of bleeding is subsequently identified from the contralateral ICA.
SPEAKER: With the shaft of the suction gently against the carotid artery to compress the site of injury, a microdissector was used to dissect and expose more of the carotid artery. Temporary clips are then placed, and repair options are considered. The 3-mm Sundt-Kees clip was too large for this narrow exposure.
SPEAKER: A thin carotid patch was then trimmed and placed as a sling around the ICA and secured with a 7-mm 90-degree aneurysm clip. Temporary clips were then removed.
SPEAKER: After the surgical repair, remaining tumor resection was performed.
SPEAKER: Postoperative angiogram demonstrated mild supraclinoid stenosis of the left ICA. Postoperative MRI showed fully resected suprasellar tumor with some intrasellar residual. The patient's vision declined initially after surgery, but it improved slightly by discharge. Otherwise, she was neurologically intact. This case shows a technical error in the use of the ultrasonic aspirator beyond the capsule of the tumor contralaterally.
SPEAKER: This was further exacerbated by the requirement for elevated settings to resect the highly fibrous tumor. Note that although the tumor did not encase the carotid artery, a similar complication could occur in that scenario. Regarding opportunities for improvement, neuronavigation can often guide the surgeon while navigating critical structures, but there is no measurement errors before the dura is opened and certainly after CSF egress.
SPEAKER: In this case, the contralateral supraclinoid ICA abutted the suprasellar portion of the adenoma with tumor located both above and below it. Debulking in that direction of the contralateral ICA is relatively blind. And thus, while navigation may assist in the understanding of its proximity, great care must be taken to locate it while tumor is being resected.
SPEAKER: Other technical improvements could include clearing the ipsilateral or near field earlier during the case before moving to the contralateral side. This might have provided better visualization, potentially preventing the injury, and could have provided more space for repair options following the injury. Visualization and control of bleeding in the setting of this type of injury requires special maneuvering.
SPEAKER: Rather than direct suctioning on the artery, we used lateral pressure from the shaft of the suction for gentle compression. In addition, we performed further tumor removal until 360-degree exposure of the carotid artery was achieved to perform an adequate repair. In the setting of a carotid injury during tumor resection, there are several options for repair. First, direct surgical repair.
SPEAKER: However, this was not an option in this case due to the minimal working space available. Second, an encircling aneurysm clip could be used. But again, this was unavailable in this case due to the narrow exposure. Third, a sling with a thin carotid patch and an aneurysm clip worked well. It's important to note that if the vascular injury had been larger, preventing adequate control of the bleeding and further repair, then the surgeon must be prepared for a worst case scenario, including possible surgical or endovascular sacrifice of the vessel.
SPEAKER: Surgical complications arise from three basic causes: poor knowledge, poor planning, and poor execution. We present a case that highlights our ability, in spite of years of experience, months of planning, and multidisciplinary tumor board evaluations, to fall into all three of these traps in one single case. That the patient survived our missteps conveys us no credit. That the patient survived our missteps conveys us no credit.
Segment:10 Part 10.
SPEAKER: In the past decade, a woman was being monitored for an expanding lesion in her right petrous bone. Her complaints that led to imaging included the history of migraine headaches with nausea and photophobia, intermittent ringing in the right ear, and right aural fullness.
SPEAKER: She also had complaints related to a contralateral ear on the non-lesional side in the form of tinnitus and intermittent swooshing sounds. Her audiogram was completely normal. Imaging showed the presence of a mass in her petrous bone. The same imaging had remained stable for three years without any symptoms. Her first consultation was two months after giving birth. And her primary goal was to bond with her new baby.
SPEAKER: She was not considering any surgical options at that time. The suspected diagnosis was chondrosarcoma. She remained asymptomatic despite gradual progression of her tumor. As the tumor progressed, we recommended surgical resection using an endoscopic endonasal transpterygoid approach. Because of significant pneumatization of the petrous bone, we considered an anterior transpetrosal approach too risky for CSF leakage.
SPEAKER: Since the patient was asymptomatic, she declined surgery. This continued for several years until the patient suddenly developed diplopia from a right abducens palsy, intermittent numbness in all three divisions of the right trigeminal nerve, and a feeling of aural fullness. She then agreed to undergo surgery. During the endoscopic transpterygoid approach, we encountered the mass that was much firmer than the common chondrosarcoma even though we had anatomic confirmation by navigation.
SPEAKER: The pathology team believed that we were only taking biopsies of dense fibrous tissue and must be outside the mass. We partially resected the lesion using scalpels and rongeurs, but did not pursue total resection due to its firm attachment to the carotid artery and cranial nerves. After the surgery, the patient's abducens palsy was resolved, but she developed a new right hypoglossal palsy.
SPEAKER: She was happy with the resolution of her double vision. We recommended radiation based on prior biological behavior of the lesion. But the radiation team declined because of lack of definitive diagnosis. Molecular markers for chondrosarcoma were not available at the time of the first operation. After an initial tissue examination yielding inconclusive results, the patient was kept under observation for nine months.
SPEAKER: During that time, evidence of regrowth into the surgical cavity was observed. The patient's symptoms also worsened with the recurrence of her right abducens palsy. Over the ensuing year, we remained in a state of uncertainty as the mass slowly fill the space created by the prior resection. After careful consideration, we recommended a repeat operation using the same surgical approach, but with a broader exposure given the tumor consistency.
SPEAKER: To provide an overview, we present the relevant endoscopic endonasal anatomical boundaries needed to access the lesion. This is known as Gardner's triangle. This outlines the structural boundaries that are imperative to understanding the endoscopic endonasal anatomy. The limits of Gardner's triangle are the periclinal internal carotid artery, the abducens nerve posterior medially, and the petroglyph synchondrosis inferiorly.
SPEAKER: We planned a repeat of the endoscopic transsphenoidal and transpterygoid approach to remove the right petrous tumor. During the second surgery, we removed portions of the mass using scalpel and CUSA. Chondrosarcoma was finally confirmed. However, we accidentally nicked the inferolateral wall of the cavernous sinus with a diamond bur, not just once but twice.
SPEAKER: During the second episode of bleeding, we saw some pulsatile bleeding, but remained unconvinced that the carotid artery was injured. Both times, the bleeding stopped with injection of Surgiflo. In retrospect, some of the hemostatic material entered the carotid artery and resulted in a distal embolic stroke. The patient woke up from surgery with left hemiparesis. Postoperative neurological examination revealed signs of neglect of the left side, right-sided facial palsy, and left hemiparesis.
SPEAKER: An MRI scan revealed embolic strokes on the right hemisphere, but the follow-up CT angiogram showed no evidence of dissection of vascular pathology. The patient was discharged to an inpatient rehabilitation facility three days after surgery with some mild left-sided neglect. On the 10th day after her surgery, she experienced profound and sudden epistaxis and was rushed back to our emergency department.
SPEAKER: We proceeded with stent coiling after a cerebral angiogram revealed a pseudoaneurysm on the inferior cavernous segment of the carotid artery. Two days later, a repeat cerebral angiogram showed occlusion of the cavernous segment of the carotid artery, reconstitution of the right supraspinal carotid via the ophthalmic artery, and robust left and right collaterals via the anterior communicating artery without venous delay.
SPEAKER: The patient was asymptomatic at this time. To restate our opinion, that the patient recovered from the majority of these insults in good condition is a testament to luck rather than proper knowledge, planning, or execution. The first misstep was delaying surgical intervention, even though tumor growth was evident, and the patient was still asymptomatic. The patient declined surgery against advice, but we went along with this for two years until she presented with neurological deficits.
SPEAKER: This was poor judgment on our part, since we could have made a far more convincing argument for early surgery. The second misstep was poor execution. One surgery should have been enough. And we should have completed resection of the mass on the first attempt. The anatomical information from navigation, the symptomatic and radiographic progression seen over time should have been sufficient to override the inconclusive results from pathology.
SPEAKER: The third misstep was poor execution at the second surgery. First off, injuring the carotid artery should have been avoided despite the anatomical distortion by scarring in the tumor. Second, and perhaps more importantly, with pulsatile bleeding from the area of the cavernous sinus, liquid hemostatic agents should not be used. As it happened, penetration of the agents into the carotid resulted in embolic strokes.
SPEAKER: Possibly, Surgicel fibrillar or crushed muscle should have been used instead. The fourth misstep was using CTA rather than cerebral angiography. This was born out of complication fatigue: the feeling that we had put the patient through so much unnecessary trauma that we needed to stop. This reluctance to pursue another invasive study pushed us to skip the proper study.
SPEAKER: We might have identified the pseudoaneurysm at that time prior to life threatening epistaxis. I received a backhanded compliment from my mentor earlier in my career at a morbidity and mortality conference. Quote, "Thank you so much for presenting this complication. Your colleagues seem to keep making the same mistakes over and over again. But you, on the other hand, make new complications that we never even knew were possible," unquote.
SPEAKER: Our patient is asymptomatic at this time, and her residual tumor has been treated with proton beam therapy. Her case has a permanent place in my cemetery of regrets.
Segment:1 Part 1.
SPEAKER: We are presenting the case of a 43-year-old man who presented with an intracerebral hemorrhage due to a ruptured right posterior medial temporal AVM. Unfortunately, in spite of recommendation of treatment, he was lost to follow-up and presented a year later for treatment. When he presented the second time, he was fully intact. The original imaging studies are shown here. This is a CT scan showing a large temporal lobe hematoma on the right side, and an angiogram at the time showed an anterior choroidal artery AVM, draining deeply into the internal cerebral vein, down to the galenic system with some superficial venous drainage.
SPEAKER: MRI a year later shows the porencephalic cyst area of the previous hemorrhage. The nidus is seen, and there is some supply from the lenticulostriate in addition to the anterior choroidal artery. So the decision making was that this was a Spetzler-Martin grade II with supplementary grade VI AVM. There is a high risk for complications from anterior choroidal artery embolization, and radiosurgery would achieve only a 45% seizure-free status.
SPEAKER: Therefore, in view of all of that, we recommended surgery to go transylvian through a right temporal frontal craniotomy, go through the transinferior circular sulcus approach, and resect the AVM. This is a surgical route seen on an anatomical specimen to indicate the approach. The plan was to identify the anterior choroidal artery from its takeoff from the internal carotid until the inferior choroidal point where it then disappears into the ventricle.
SPEAKER: Then we get through the inferior circular sulcus to the lateral ventricle where we would see it again—the distal end of the anterior choroidal artery. This way, we avoid taking the branches from the external segment of that artery and other branches prior to the inferior choroidal point. At surgery, we can see now that we are splitting the sylvian fissure from distally to proximally very widely because it is important to mobilize the temporal lobe laterally and get all the way down to the origin of the anterior choroidal artery and able to follow it from proximally to distally.
SPEAKER: Sharp dissection is used to split the sylvian fissure. We will pass by the limen insulae down to the carotid cistern. Here is a good view of the supraclinoid carotid and the origin of the anterior choroidal artery. Here is a good view of the anterior choroidal artery supply on its way to the choroidal point.
SPEAKER: Here is an anatomical depiction of that location. The uncus is mobilized posterolaterally. And we have a good view of the posterior cerebral artery. Here, we enter the porencephalic cyst, where the previous hematoma was present as an initial dissection through the insular cortex. We begin coagulating with a nonstick irrigating bipolar.
SPEAKER: The small AVM feeders staying close to the margin of the AVM in spite of its diffuse nature. We are monitoring intraoperative SSEP and MEPs. We here enter the temporal horn of the ventricle and clearly visualize the choroid plexus, which gives us a good demarcation point laterally.
SPEAKER: We proceed around the margin of the AVM anteriorly and detach more feeders. The nidus is becoming better defined the more we dissect it. We now proceed along the medial border of the AVM.
SPEAKER: This is a very clear feeding artery that is taken. And now, as we look deeper on the medial surface, we encounter some small arterial structures. And you can notice the hesitation of not knowing if they are feeders or not. We eventually decide to take them assuming they are feeding the medial deep surface of the AVM.
SPEAKER: Unfortunately, within 5 minutes after this bipolar coagulation, one can see the flattening of the evoked potentials. And we realized immediately that these are lateral lenticulostriates. We proceed with the resection of the nidus of the AVM away from the zone of troublesome coagulation and staying much closer to the nidus wall as can be seen here until the specimen is completely free and taken out.
SPEAKER: There was only a partial return of the evoked potentials, as can be seen here by this point. Postoperatively, unfortunately, the patient had an infarction as can be seen on the diffusion-weighted sequence in the corona radiata and capsular region.
SPEAKER: He was agitated and confused with 2 out of 5 hemiparesis. His mental state improved over several days. The opportunities to improve may be related to the use of interop angiography. After delineation of the AVM, we might have proceeded with resection of the AVM and left the questionable areas alone, as it was unclear if it directly supplied the AVM.
SPEAKER: Intraoperative digital subtraction angiography might have shown complete resection of the AVM, thus providing confirmation that coagulation of the questionable vessels was not necessary. It is unfortunate that the interop navigation was inaccurate in this case. Perhaps interop ultrasound may have helped. Certainly, a reminder constantly of the normal anatomy is important.
Segment:2 Part 2.
SPEAKER: This case involves surgically induced venous sinus thrombosis. This case involves surgically induced venous sinus thrombosis. The clinical presentation is a 66-year-old woman, who presented with progressive confusion, gait difficulties, and right-sided hearing loss. Her MRI showed a large right-sided Koos grade IV vestibular schwannoma with an element of hydrocephalus. Here you can see the MRI. The rationale for treatment is that she was becoming increasingly symptomatic with her large tumor.
SPEAKER: The risks of removal of the tumor included hemorrhage, ischemic stroke, new cranial nerve deficit, aside from her hearing loss and infection. Anticipated problems were that she may require a VP shunt in addition to tumor resection. Our plan was to assess her following resection and see if she required a shunt. The chosen plan was retrosigmoid resection of a Koos grade IV vestibular schwannoma.
SPEAKER: We did consider a translabyrinthine approach, but chose a retrosigmoid approach in this particular case, for the reason that the corridor of the tumor was already present with the location of the arachnoid cysts posterior to the tumor. But we do in fact do more cases translabyrinthine than retrosigmoid. We proceeded with the tumor resection, and the postoperative details will be described.
SPEAKER: We exposed the retrosigmoid region and performed a craniectomy in this region. We opened the dura in a cruciate fashion. And you can see the sigmoid transverse junction was exposed. We placed one cut to the transverse sigmoid junction and another cut to end at the inferior aspect of the sigmoid. The flaps are placed, as shown here, where there's a superior flap at the transverse sinus and a lateral flap at the sigmoid sinus.
SPEAKER: This exposed the sinus over a length. In this particular case, it may have been helpful to cover the transverse sinus and the sigmoid junction where it was exposed perhaps with a moist cottonoid. This was not performed. The question would arise whether a translab approach would increase or decrease the chance of a clot. But we've certainly experienced thrombosis of the sigmoid sinus with the translab approach as well.
SPEAKER: The tumor is exposed, and we perform a resection of the capsule and then use an ultrasonic aspirator to progressively debulk the tumor. Here you see dissection of the inferior part of the tumor from the lower cranial nerves and identification of the brain stem.
SPEAKER: We identified the eighth nerve and ligate and divide this. And we proceed with our dissection and debulking of the tumor and removal of the capsule. Here is an extracapsular dissection, and we'll remove a large portion of the capsule that does not involve the facial nerve. And we now identify the facial nerve at the brain stem and follow this up toward the internal auditory canal. Here we identify the internal auditory canal and then proceed with drilling of the IAC.
SPEAKER: We cauterized the dura up to the region of the endolymphatic sac and drill out the posterior lip of the internal auditory canal. After adequate exposure of the canal, we open up the dura over the region of the tumor and continue debulking of the tumor from the internal auditory canal.
SPEAKER: We remove all the tumor within the canal and then progressively remove the tumor at the lip of the porus acusticus. But we find a very adherent aspect of tumor just at the lip of the porus acusticus. So we do a subtotal resection and thin this carpet of tumor. We then place fat in the IAC to forestall CSF leak and then proceed with closure. Please note the desiccation of the dura overlying the sigmoid sinus here.
SPEAKER: The dura was closed in an interrupted fashion using NURULON suture, and a cranioplasty with MEDPOR was used to cover the defect. The scalp was closed. Her postop day 1 scan shows no complications, with the exception of a thrombosed sigmoid and transverse sinus on the ipsilateral side. We felt this was a consequence of having an exposed and desiccated sinus and also perhaps suturing and injuring the sinus with a suturing when closed.
SPEAKER: At this time, she was continuing to be hydrated postoperatively and we did add daily aspirin. Postoperative day 4, we noticed increasing edema in the cerebellar peduncle and an impending venous infarction in this area. So she was anticoagulated with a heparin drip, and this was started with a slow start of anticoagulation to ramp up to full anticoagulation over several hours.
SPEAKER: On postop day 5, she had an acute neurological decline. She became relatively comatose in a rapid period of time, and an emergency CT scan here demonstrates a hematoma within the resection cavity and involving the area of venous infarction. She had acute hydrocephalus associated with this. She was taken to the operating room and the hematoma was evacuated, and a ventriculostomy was placed.
SPEAKER: Subsequently, she had an extensive ICU course with CSF drainage and was ultimately sent to rehab after several weeks. She required a permanent VP shunt for hydrocephalus and she was left with permanent neurological deficit from this hematoma. And she has unsteady gait and she has increased facial nerve weakness. We presume that the facial nerve deterioration was a result of the hematoma and increasing trauma to the facial nerve.
SPEAKER: She was a House-Brackmann II immediately after surgery, and she went to a House-Brackmann IV. Here's the delayed postop scan at day 60, and you can see the extensive venous infarction in the cerebellar peduncle and the VP shunt placed for hydrocephalus. The radiographic outcome demonstrates that the tumor was resected, but there was extensive venous infarction of the peduncle and hydrocephalus.
SPEAKER: Analysis of the complication: We believe that there was no error in diagnosis or risk anticipation in this case. The flaw was in the execution of the treatment plan, which was thrombosis of the venous sinuses adjacent to the operative site. This is a routine approach, and it was due to desiccation of the dura and injury of the sinus with exposure and using sutures that were woven to close the dura adjacent to the sinus resulting in thrombosis of the sinus.
SPEAKER: Subsequently, with the developing impending venous infarction, she was anticoagulated which promoted hemorrhage into this region. The question has arisen as to whether anticoagulation was indicated in this case. It has been our practice to not treat incidental thrombosis of sinuses if it is not a dominant sinus. However, given the fact that she was developing increasing edema and the evidence of a venous infarction, we chose to anticoagulate.
SPEAKER: The literature would support this treatment paradigm. What did this teach us? The technical improvement is to avoid injury and limit exposure to the venous sinuses during opening. This is a routine operation and all sinus repair should be performed with vascular sutures, not woven sutures, to avoid induction of thrombosis. This includes closing the dura adjacent to the sinus. More recognition of the potential for venous injury and its consequences during a routine exposure is important.
SPEAKER: This case is interesting insofar as the venous sinus was not dominant on this side, but was still very important because a large draining vein affecting the cerebellar peduncle was involved and became thrombosed with injury to the sinus. Thus, one may not appreciate the consequences of sacrifice of a sinus that is not dominant.
Segment:3 Part 3.
SPEAKER: The patient in this case was a 75-year-old man presenting with gait disturbance and frequent falls because of it.
SPEAKER: When he started to get headaches, an investigation was done. His neurological examination was unremarkable except for unsteady gait. His MRI showed a large petrochemical meningioma extending from the chiasmatic cistern down to just inferior to the level of the internal acoustic canal. Brainstem compression was significant, which accounted for his symptoms.
SPEAKER: There was also brainstem edema, but no hydrocephalus that would account for the wobbly gait. One unusual aspect of this tumor was the position of the basilar artery, which is denoted by the red dot here. Most petroclival meningiomas pushed the basilar artery to the opposite side. This one completely surrounded the artery, which meant that the perforators that supply the brainstem were entirely within the tumor.
SPEAKER: Surgical intervention was indicated because the patient was still relatively healthy. And his symptoms were not only debilitating, but likely to progress rapidly. Brainstem decompression was a rational goal. The major risks to the basilar artery and its perforators were noted before surgery. The entire surgical team was well aware of the danger of hurting these small perforators.
SPEAKER: Because the tumor extended superiorly beyond the dorsum sellae, a posterior petrosectomy was deemed suboptimal and an anterior petrosectomy approach with drilling of the Kawase quadrilateral was considered the best option because it would expose the whole area of the tumor from superior to inferior. And since the right side was involved, the dominant temporal lobe would be spared any risk.
SPEAKER: The drilling of the anterior petrosectomy proceeded in standard fashion. The posterior fossa and middle fossa dura were opened perpendicular to each other, and the superior petrosal sinus, along with the tentorium, were coagulated and then cut. As we neared the incisura, we discovered that the fourth nerve was hopelessly engulfed by the tumor.
SPEAKER: Painstaking dissection revealed the posterior cerebral artery. And with some debulking, the superior cerebellar artery was also found. Both of these were significantly adherent to the tumor. Interpreting this as a personal challenge for one's skill is a bad idea. Debulking laterally and anteriorly were without difficulty, but working on the brain stem side, we encountered these perforators.
SPEAKER: And eliminating them as blood supply simply to the tumor was also a bad idea. These are brain stem perforators. The basilar artery was visualized. And again, working lateral and anterior to it proceeded smoothly. But trying to dissect the tumor between the basilar artery and brain stem was a different story.
SPEAKER: At the base of your screen is the brain stem, and the tumor was attached to the pia firmly, which indicated infiltration. Working more between the basilar artery and brainstem, we encountered bleeding from small arteries like this. This should have been interpreted as a signal to stop working in this area, but yet the decision was to move forward aggressively.
SPEAKER: For this, these tiny arteries cemented by the tumor stood no chance. Here is one more of those small perforators, and it should have been left alone along with the tumor that surrounded it.
SPEAKER: After reaching the inferior limit of the exposure at the level of the IAC, we worked back up the basilar artery. Portion of the tumor under the trigeminal nerve was the last to be removed. And with that, we have the full view of the surgical field here. The cottonoid estimates the extent of the exposure. Postoperative MRI showed a minimal residual tumor in the area where we worked, but there was massive edema of the brainstem.
SPEAKER: DWI indicated ischemia from the midbrain down to the pons. The patient remained in a coma after surgery. After several weeks without improvement, the family decided to transition to comfort care, and the patient expired. Whereas the plan for decompression of the brainstem was sound, the brainstem edema should have been interpreted as pial invasion by the tumor and blood supply from the basilar perforators.
SPEAKER: This, in turn, should have made the surgical strategy more conservative. Since the meningioma completely engulfed the basilar artery, a total or even near-total resection was simply not possible. The perforators have to travel through the tumor to reach their target, that is, the brainstem. The path might be direct, but it could also be very circuitous.
SPEAKER: As soon as the perforators were encountered, the notion of stopping must be entertained. It's very tempting to try to dissect the perforator from the tumor. But this is a bad idea. You might get lucky with the first one. But with the next one, you might not. And bleeding from these tiny vessels can only be stopped with coagulation, which, as we can see, leads to poor outcome.
SPEAKER: As such, the configuration of the perforators determines how much residual you must leave behind. The specific lessons to be learned are for better interpretation of brainstem edema with a high level of caution to be less aggressive. And once perforators are encountered, you must stop. Taking more tumor toward the brainstem can lead to catastrophic outcome. Extensive monitoring might have stopped the injury to multiple perforators, but signal changes from even a single perforator injury could prove devastating to the patient.
SPEAKER: This complication illustrates that despite clear articulation of the surgical goal and understanding of risky areas, it is still possible to lose track of those once the operation starts. Even as one focuses on resection of the tumor as the task at hand, one cannot lose track of the surgical goal and risk assessments.
Segment:4 Part 4.
SPEAKER: This is the case of a 32-year-old female, who presented with visual field deficits corresponding to a left-sided clinoidal meningioma.
SPEAKER: Due to the progressive nature of the deficits, left-sided pterional craniotomy was undertaken to remove the tumor and decompress the optic nerve. The exam in this case was only positive for decreased visual acuity and narrowed visual field in the left eye. MRI examination axial T1 with contrast image demonstrates the meningioma that is somewhat en plaque around the area of the clinoid with evidence of crinoidal hypertrophy and hyperostosis, as well as evidence of tumor encasing the nerve into the optic canal.
SPEAKER: The treatment was necessary due to the progressive nature of the visual field deficits and the risks included injury to the optic nerve and other potential vascular complications. Due to the extension of the meningioma to the optic canal, an extradural clinoidectomy was contemplated and conducted as the first phase of the operation before the dura was opened and after the craniotomy was completed.
SPEAKER: This would allow the decompression of the optic nerve early on, and this would minimize the chance of traction injury to the optic nerve during manipulations related to intradural tumor removal. The plan was to open the dura after the clinoidectomy and remove the tumor inside the canal by opening the falciform ligament and also being able to remove additional tumor in the region.
SPEAKER: The clinical scenario in this case, as it unfolded, was that during drilling and hollowing out the clinoid process, the operator was very focused on the protection of the optic nerves and suffered from cognitive tunneling and did not pay adequate attention to the other structures underlying the clinoid, including the carotid artery.
SPEAKER: In addition, the operator pressed on the drill significantly to make sure the bone is removed. And this maneuver led to the injury of the carotid artery and significant bleeding. This is the video of the procedure. Again, a left-sided pterional craniotomy. The optic canal was unroofed.
SPEAKER: The clinoid is being hollowed out. As you can see, the operator is pushing on the drill without any off and on episodic relaxation to have more proprioceptive feedback on where he or she is drilling. As the bleeding was encountered, we were unable to conduct a primary repair. Therefore, a piece of cotton soaked in thrombin was used to create a tamponade in the region and to keep the tamponade in place after the bleeding was stopped, and hemostasis was reached.
SPEAKER: The dura was opened and then tacked to the area of the pericranium to almost externalize this area from the internal space and keep pressure on the piece of cotton. This maneuver was very effective. Intradural decompression of the nerve and opening of the falciform ligament and removal of the tumor within the optic canal was conducted effectively, and this patient did not suffer from any untoward effects.
SPEAKER: A gross-total resection was achieved. The patient had an unremarkable recovery. Postoperative CT angiogram was unremarkable, and the 3-month angiogram, as you can see here, demonstrated no evidence of pseudoaneurysm formation. Analysis of this complication demonstrated the concept of cognitive tunneling—that the individual surgeon in this case suffered from some sort of blindness, albeit unintentional.
SPEAKER: And this can occur during surgery when the surgeon is so focused on a specific task at hand that he or she inattentively neglects other stimuli or relevant information in the surgical field. The operator should press the drill against the bone in a controlled fashion and in short episodes while considering all structures at risk.
SPEAKER: The use of a coarse diamond drill bit could have contributed to this injury. The specific lesson learned is that less is more. Performance of a direct repair or bypass may not be needed in many occasions, as small vascular injuries can be managed effectively via small piece of cotton and gentle tamponade. Pseudoaneurysm formation is not universal, and drilling should be conducted in a gentle and dynamic off-and-on maneuver rather than a more forceful, continuous activity to allow for more effective proprioceptive feedback against the bone.
SPEAKER:
Segment:5 Part 5 .
SPEAKER: This young man in his mid 20s had a hemorrhage from this lesion in the cervical spinal cord, which resulted in temporary quadriplegia. Over time, he made a very good recovery. The therapeutic assessment was as follows. After one episode of quadriplegia, the patient was presented with options, and he, with the support of his mother, was eager to proceed with treatment.
SPEAKER: And after reviewing the studies, we considered him to be a very good surgical candidate with a high likelihood of a successful outcome. The patient and his mother were fully aware of the associated risks and alternative treatments and elected to proceed with surgery. The plan for treatment was embolization of the arteriovenous malformation, resection of the AVM through C4-6 laminoplasty.
SPEAKER: On the MRI scan, we see the involvement of the AVM in the spinal cord and the effects of the previous hemorrhage with edema around the lesion. We also noticed that the arteriovenous malformation is not in the midline but off to the side, making it much more accessible for surgical intervention. An angiogram demonstrates the spinal arterial venous malformation, which was embolized as much as possible.
SPEAKER: After embolization, the patient was brought to the operating room, where through a laminoplasty, the arteriovenous malformation was exposed. And using bipolar coagulation, it was separated from the spinal cord. Even though we are aware that there is AVM inside the spinal cord, experience has taught us that we could resect and go through the AVM, obliterating the components that went into the spinal cord and then removing the portion of the AVM that was in the lateral gutter.
SPEAKER: We see the Onyx down low, the black filled portion of the arteriovenous malformation. Through this posterolateral approach, we had good access to the lesion and resected it uneventfully. During this time, monitoring remained unchanged, and that included sensory as well as motor evoked. With the resection of the AVM, monitoring was discontinued, and the laminoplasty replaced in the usual fashion.
SPEAKER: The patient was taken directly to the angio suite, where complete excision of the AVM was demonstrated. With the patient returned to the recovery room, it was apparent that he had quadriplegia. This completely unexpected exam led to the patient being taken emergently to the CT scanner, where the following CT scan demonstrated compression of the spinal cord with the laminoplasty.
SPEAKER: The patient was rushed back to the operating room where the compression was removed. Following the surgery, the patient had a severe motor deficit with quadriplegia and severe sensory deficit. He was, after several days, turned over to rehabilitation, where over the following 10 days, he recovered significant sensation but no significant motor function.
SPEAKER: He returned to his home country for further physical therapy. A 10-month follow-up, we received the following information from him where he says, quote, "I'm doing great. Just finished my occupational and physical therapy. Currently, I'm able to stand and walk using a walker. However, temperature and pain sensation is still nonexistent. Still, I'm content with my recovery," unquote.
SPEAKER: To me, this is as bad of a complication as we can possibly have, as it is one that can be completely avoided. We learned from this a number of points. One is to make triple certain that the laminoplasty is appropriately secured; to continue monitoring even during closure of the evoked potentials, sensory and motor; and returning the patient immediately to the operating room instead of getting a stat CT scan, since the only causes that are remedial are compression, either from the laminoplasty or more likely from a hematoma, and a stroke, which surgery would not help and which would be very, very unlikely.
SPEAKER: And since time is so important, this is a critical point. We further developed some spacers for laminoplasty, so that the cut from the saw can be compensated. But these are not commercially available. This case greatly emphasizes that there is no portion of the surgery that does not have a potential for a serious complication.
SPEAKER: This particular complication rests on my conscience to this day.
Segment:6 Part 6 .
SPEAKER: We are describing the case of an 80-year-old female who was quite disabled by bad hemifacial spasm on the left side, not helped by Botox.
SPEAKER: She was otherwise intact. The MRI shows dolichoectatic left vertebral artery compressing the exit zone of the facial nerve. We discussed the treatment and the rationale for it. We proposed retrosigmoid craniotomy to use a sling clip technique to elevate the vertebral artery of the exit zone. This is a quite well known technique because the Teflon felts are insufficient in relieving spasm from large vertebral artery.
SPEAKER: Here at surgery, one can see the use of the NIM stimulator to identify the origin of the facial nerve. The tortuous vertebral artery is well seen anterior to cranial nerves 9 and 10. And here it is lifted with the sucker off the exit zone of the seventh nerve.
SPEAKER: In order to keep it in a position that is away from the facial nerve, we are using this Gore-Tex sling, which we fashioned with an appropriate width to fit around the vertebral artery. We are anchoring one end of it to the petrous dura with a 5-0 Prolene suture. We then used the other end to elevate the vertebral artery.
SPEAKER: However, we are very cautious of that perforator that can be seen along the sucker. It appears that the edge of the Gore-Tex will kink it. So we are cutting a window into the Gore-Tex to allow passage of the perforator before finalizing the position. We are trying again, suspending the vertebral artery anterolaterally and watching the perforator.
SPEAKER: We then put an aneurysm clip to hold the sling in this exact position. And we inspect the perforator again, but we are not confident that it is patent. We released the construct and decide to do it again with a narrower piece of Gore-Tex, which we are fashioning here.
SPEAKER: By bypassing it around the vertebral artery, we now are farther away from the perforator. But this time, because we don't want the Gore-Tex sling to slip toward the perforator while we are suspending it, we will reverse the steps by placing an aneurysm clip on the Gore-Tex sling in the exact position that we want it. And then we will suspend it.
SPEAKER: We can see that the perforator is quite clearly unencumbered by the sling. And we are very satisfied with this position. Now, to suspend it to the petrous dura, it would have been awkward to use a Prolene. So we are making a small slit in the petrous dura big enough to allow the passage of one blade of an aneurysm clip.
SPEAKER: And then we will hold the dura and double sling with the permanent aneurysm clip as shown here. We now are inspecting everything. And we realize that there is an AICA branch that is also compressing the facial nerve. First, we place Teflon felt between the vertebral artery and the exit zone.
SPEAKER: And then we lift the AICA to place Teflon felt between it and the exit zone as well since we cannot be sure which of the two arteries is the more offending agent. Here are triangular pieces of Teflon felt going between the AICA and the brain stem.
SPEAKER: Further inspection, more proximally on the vertebral artery, indicates that we might want to add another bridge of Teflon just to be absolutely certain that the entire course of the vertebral artery has been redirected away from the facial nerve and its exit zone.
SPEAKER: One can see the hypoglossal nerve draped on the vertebral artery to the left of the piece of Teflon. The lateral spread potential disappeared at this point, indicating good decompression. We add a Ligaclip to the free ends of the sling for added security. And we complete the closure.
SPEAKER: A postop CTA indicates the new position of the vertebral artery, and the clips can be clearly seen. Postoperatively, she had a left House-Brackmann grade III, left anacusis ataxia, unable to ambulate. The facial weakness worsened at 6 weeks to a grade VI. At 4 months, she was still having significant difficulty walking. The complication is clearly a small brainstem infarction from occlusion of a brainstem perforator.
SPEAKER: One could have been even more meticulous with the perforator in spite of our best efforts. Perhaps we should have used ICG videography. Even though we actually use it quite routinely in similar cases, it is possible that the perforator may have been kinked even after the closure, while it looked quite preserved during the surgery. One will remember that CSF and brain shifts do occur after closure of a craniotomy, and the patient is mobilized.
SPEAKER: The sling clip technique is useful in cases of compression caused by large arteries such as basilar artery or vertebral artery. With simple MVD, placing Teflon felt between the offending vessel and the nerve may not be sufficient. Had there been no possibility to save the perforator, other configurations of Teflon could have been considered.
Segment:7 Part 7.
SPEAKER: other configurations of Teflon could have been considered.
SPEAKER: other configurations of Teflon could have been considered. The patient was in his late teens. He had multiple family members with prior aneurysmal subarachnoid hemorrhage. Here is his angiogram, which shows a 7-mm fusiform aneurysm of the distal p1 and p2 segments of the right PICA. Of note, there is a branch coming off the side of this dolichoectatic aneurysm. The patient's strong family history of aneurysmal subarachnoid hemorrhage prompted treatment, as well as did his young age and the opportunity for a cure.
SPEAKER: Risks and benefits of the surgery are listed here. Far lateral craniotomy, dissection into the cisterna magna to expose the V4, PICA, the aneurysm, and its branches; aneurysm trapping and excision; first, an end-to-end reanastomosis of the PICA trunk to the PICA origin.; second, an end-to-side reimplantation of the p2 PICA branch to the distal PICA trunk. First, the aneurysm was trapped between temporary aneurysm clips.
SPEAKER: Here, I'm transecting the proximal end of the aneurysm and freeing the aneurysm for its resection. Inspecting this proximal stump reveals that there is still pathology in the arterial wall here. There's thickness of the artery and pathologic appearance. And so I excised that as well. I'm all the way to the V4 segment here, and I still am concerned about the amount of pathology in that stump.
SPEAKER: I've readjusted my clips now, placing them on the vertebral artery. This allows some additional PICA to be resected all the way back to the origin at the V4 segment. Here, the main trunk of PICA is brought together with this first stitch to the stump of PICA. Now a running continuous suture line was placed to complete the first half of the anastomosis. The artery was rotated slightly.
SPEAKER: And the second wall of the anastomosis could be completed again with running continuous suture. And initially, the bypass was patent. Now, the second efferent branch from the aneurysm was prepared for reimplantation to the PICA trunk. Here, the toe stitch is being placed, and now the suture can be run along the first suture line. Here, the second suture line is being sewn, and this completes the anastomosis.
SPEAKER: As the temporary clips are removed and hemostasis is achieved, we can see that this graft is nicely patent. However, inspection of the initial end-to-end reanastomosis reveals that the first bypass has occluded. Doppler flow probes demonstrate that the end-to-end reanastomosis is not flowing. And disruption of platelets with my bipolars does not succeed in keeping this patent.
SPEAKER: Therefore, this reanastomotic bypass is taken down. I coagulated the connection of the stump. And I'm transecting the trunk free. As we inspect the lumen of the PICA trunk, you can see that the platelet plug is very dense and very adherent. It was impossible for me to clear the lumen and use this for the anastomosis. Fortunately, the distal PICA could be mobilized upward.
SPEAKER: And unfortunately, the medullary perforators tethered the more proximal portion of PICA. Therefore, I decided to do a side-to-side reimplantation. Here, the arteriotomy is made in the vertebral artery. Next, an arteriotomy is made in the distal p2 segment. This first stitch approximates the PICA to the V4, and now I'm doing this side-to-side anastomosis, bringing the two inner layers of the walls together. And now I am sewing the second two layers over the top to complete the side-to-side in situ anastomosis.
SPEAKER: As the clip comes off of the V4 segments, we now have flow in the bypass, and IC green video angiography confirms patency of the reimplantation site. Now the PICA trunk fills off of this side-to-side anastomosis, and the second reimplanted branch fills off of that main PICA trunk. The patient tolerated the procedure well. He had no new neurological deficits.
SPEAKER: Here is his postoperative angiogram, which shows that the side-to-side reimplantation of PICA is nicely patent, as is the more distal reimplantation of the PICA branch. The 3D angiogram to the right nicely shows these two reimplantation techniques. This animation shows a fusiform dolichoectatic aneurysm arising from the distal PICA with two outflow arteries.
SPEAKER: The aneurysm is completely trapped here with temporary aneurysm clips, and the aneurysm is excised. The primary PICA vessel is brought together with an end-to-end reanastomosis, and the secondary branch is reimplanted. The end-to-end reanastomosis subsequently thrombosed, requiring revision. The distal artery was then freed, swung to the V4 segment of the vertebral artery, and reimplanted with a side-to-side anastomosis.
SPEAKER: This case gives us opportunities for improvement. There was no error in diagnosis, perhaps some risk anticipation that was lower than expected. But the treatment plan was a good one. The flaw was in the execution. The aneurysm needed to be excised. But always with aneurysm excision is the concern that too much resection of tissue would leave a large gap that could not be bridged by the reanastomosis with an end-to-end construct.
SPEAKER: In this case, I left a little bit of pathologic tissue on the ends and incorporated that into the end-to-end reanastomosis, which ultimately led to the bypass occlusion. The opportunity for improvement would have been to excise further back to completely normal tissue and execute the end-to-end anastomosis with healthy tissue. Another specific lesson that this case teaches us is that unanticipated things happen.
SPEAKER: And we have to be ready to take that next step to that next level to get through the complication. In this case, I needed to take down a previously done anastomosis and redo it with an equally complicated side-to-side reanastomosis to the vertebral artery. This required an escalation in skill and also in the complexity of the construct, but teaches us that we have to be ready and adaptable to make that transition in response to the adverse events.
SPEAKER: This case also teaches us that there is room for innovation, particularly in bypass surgery. This was a bypass that I had never done before. And circumstances dictated that I do something unique here. The side-to-side reimplantation of PICA onto the vertebral artery is a unique construct. And it's these innovations under duress that make them even more special. Thank you.
SPEAKER:
Segment:8 Part 8.
SPEAKER: The patient presented as a 57-year-old woman with a 6-month history of progressive visual loss in the right eye. No headaches, normal left eye visual acuity. Her examination showed 4 mm of right-sided proptosis, a relevant afferent pupillary defect in the right eye, reduced color vision in the right eye, and best corrected visual acuity 20/50 in the right eye.
SPEAKER: This is the CT scan demonstrating the typical features of hyperostosis of the greater wing of the sphenoid lateral portion of the orbit and roof of the orbit. The MR shows the limited intradural component of the meningioma, as well as involvement of the greater sphenoid wing and the posterolateral periorbital. The patient was symptomatic for her declining vision, and in this therapeutic assessment, she also had objective evidence of optic nerve dysfunction.
SPEAKER: Her case was presented at our multidisciplinary skull-base tumor board, and she was recommended to decompression in combination with oculoplastic surgery, along with orbital reconstruction. Risk assessment related to the risks of general anesthesia, including pneumonia, bladder infection, postoperative venous thrombosis, and sudden death, as well as specific to the surgical approach, including wound infection, postoperative hematoma, double vision and worsening vision, and CSF leak.
SPEAKER: The chosen plan was a combined frontotemporal orbital zygomatic approach for removal of tumor-involved bone, intradural tumor with a pericranial graft, followed by removal of tumor-involved periorbita and orbital reconstruction. The procedure was done in combination with oculoplastic surgery, and the operative plan and setup included exposure of the entire face to the upper lip, so that the position of the eye could be examined after reconstruction.
SPEAKER: Standard surgical approach, coronal incision, removal of tumor involved bone and intradural tumor first, and then removal of intraorbital tumor with reconstruction using a porous polyethylene implant with embedded titanium mesh. The clinical scenario was that the operation was performed as described. Orbital roof and lateral wall were removed to the boundaries of the superior and inferior orbital fissures.
SPEAKER: The optic canal was exposed and drilled with a 2-mm diamond drill bit with copious irrigation using the operating room microscope. The intradural tumor was then resected and the dura repaired, and then the lateral tumor-involved periorbital resection was performed by oculoplastics and the periorbital defect covered by a small absorbable sponge. And the position of the globe checked versus the operative side.
SPEAKER: And then the wound closed. We performed a two-piece orbital zygomatic craniotomy with image guidance to confirm our position. The tumor involved orbit was removed. This is the orbital implant shown by a yellow arrow and the grafted convexity dura. On postoperative day 1, the patient complained of binocular, horizontal double vision. And examination demonstrated an inability to adduct the right eye beyond the midline.
SPEAKER: Forced duction under local anesthesia confirmed mechanical restriction of adduction, and a CT scan demonstrated impingement of lateral rectus by sharp edge of the zygomatic bone and inward curvature of the orbital implant, which may also affect muscle vector and function. These are examples of the postoperative CT on the top with the small arrow indicating impingement.
SPEAKER: Examples of the patient's attempt at left gaze with restricted adduction and then the confirmation of impingement with the force duction under local anesthesia. On postoperative day 2, the patient was returned to the operating room. The bony impingement was removed, And a Silastic sheet was placed between the lateral orbital and the orbital implant, and a force duction test confirming the patient had normal excursion of the right eye, seen on the bottom images.
SPEAKER: Here's the radiographic outcome confirming removal of all intradural tumor and near-total resection of intraorbital tumor, and then the CT scan demonstrated as previously described. The patient's proptosis was improved postoperatively. Analysis of the complication, opportunities for improvement: There was no error in diagnosis or treatment plan, but an opportunity was missed to prevent the observed complication.
SPEAKER: The better plan would have been to perform a forced duction test of the right eye after reconstruction at the first operation. Subsequently, this plan became part of the comprehensive plan, and thereafter, there were no cases of restricted strabismus observed. The forced duction test is a common evaluation for eye muscle entrapment. The limbus of the eye at the junction of the cornea and sclera is grasped with forceps, and the eye is moved in various directions to detect tethering: superiorly for inferior rectus tethering, inferiorly for superior rectus, medially for lateral rectus, and laterally for medial rectus, and down and medially for superior oblique.
SPEAKER: This maneuver assesses whether there is a structural abnormality in one of the four walls of the orbit impinging on eye muscle and restricting active eye movement. What did this teach us? Intellectually, there was a knowledge gap in that the risk for mechanical impingement was underestimated or not strongly considered. Technical execution: the observed event resulted in a change in our routine operative plan at the end of the procedure before replacing the cranial bone flap, in that a forced duction test had to be completed by the oculoplastic surgeon as the final step in the assessment of the orbital reconstruction.
SPEAKER: We continue to practice orbital reconstruction and perform in all cases in combination with our oculoplastic surgery colleagues.
Segment:9 Part 9.
SPEAKER: We present a 55-year-old woman with nonfunctioning pituitary macroadenoma, who underwent subtotal resection one year prior at an outside hospital. This initial MRI shows a large enhancing sellar lesion with suprasellar extension and displacement of the optic chiasm.
SPEAKER: After her first surgery, a residual tumor remained. A redo transsphenoidal resection was attempted. But due to significant scar tissue and fibrous, residual tumor persisted. Due to the persistence of her visual symptoms and unlikely resolution without further intervention, additional surgery was discussed.
SPEAKER: A transcranial approach was advised to resect the remaining tumor. In the following slide, our operative video demonstrates the transcranial approach using a right lateral supraorbital craniotomy for sellar and suprasellar tumor resection. During the surgery, the contralateral internal carotid artery suffered injury from the ultrasonic aspirator requiring repair.
SPEAKER: After performing the craniotomy, we opened the dura using a 15 blade. We placed an adapted patty over the cortex. The surgical corridor is followed to the ipsilateral optic nerve.
SPEAKER: The arachnoid is opened with microscissors. Hemostasis of the capsule is performed with bipolar. The ultrasonic aspirator is brought into the field to begin tumor resection.
SPEAKER: At this point, we note brisk arterial blood flow. Two sections are then brought into the field for better visualization. The source of bleeding is subsequently identified from the contralateral ICA.
SPEAKER: With the shaft of the suction gently against the carotid artery to compress the site of injury, a microdissector was used to dissect and expose more of the carotid artery. Temporary clips are then placed, and repair options are considered. The 3-mm Sundt-Kees clip was too large for this narrow exposure.
SPEAKER: A thin carotid patch was then trimmed and placed as a sling around the ICA and secured with a 7-mm 90-degree aneurysm clip. Temporary clips were then removed.
SPEAKER: After the surgical repair, remaining tumor resection was performed.
SPEAKER: Postoperative angiogram demonstrated mild supraclinoid stenosis of the left ICA. Postoperative MRI showed fully resected suprasellar tumor with some intrasellar residual. The patient's vision declined initially after surgery, but it improved slightly by discharge. Otherwise, she was neurologically intact. This case shows a technical error in the use of the ultrasonic aspirator beyond the capsule of the tumor contralaterally.
SPEAKER: This was further exacerbated by the requirement for elevated settings to resect the highly fibrous tumor. Note that although the tumor did not encase the carotid artery, a similar complication could occur in that scenario. Regarding opportunities for improvement, neuronavigation can often guide the surgeon while navigating critical structures, but there is no measurement errors before the dura is opened and certainly after CSF egress.
SPEAKER: In this case, the contralateral supraclinoid ICA abutted the suprasellar portion of the adenoma with tumor located both above and below it. Debulking in that direction of the contralateral ICA is relatively blind. And thus, while navigation may assist in the understanding of its proximity, great care must be taken to locate it while tumor is being resected.
SPEAKER: Other technical improvements could include clearing the ipsilateral or near field earlier during the case before moving to the contralateral side. This might have provided better visualization, potentially preventing the injury, and could have provided more space for repair options following the injury. Visualization and control of bleeding in the setting of this type of injury requires special maneuvering.
SPEAKER: Rather than direct suctioning on the artery, we used lateral pressure from the shaft of the suction for gentle compression. In addition, we performed further tumor removal until 360-degree exposure of the carotid artery was achieved to perform an adequate repair. In the setting of a carotid injury during tumor resection, there are several options for repair. First, direct surgical repair.
SPEAKER: However, this was not an option in this case due to the minimal working space available. Second, an encircling aneurysm clip could be used. But again, this was unavailable in this case due to the narrow exposure. Third, a sling with a thin carotid patch and an aneurysm clip worked well. It's important to note that if the vascular injury had been larger, preventing adequate control of the bleeding and further repair, then the surgeon must be prepared for a worst case scenario, including possible surgical or endovascular sacrifice of the vessel.
SPEAKER: Surgical complications arise from three basic causes: poor knowledge, poor planning, and poor execution. We present a case that highlights our ability, in spite of years of experience, months of planning, and multidisciplinary tumor board evaluations, to fall into all three of these traps in one single case. That the patient survived our missteps conveys us no credit. That the patient survived our missteps conveys us no credit.
Segment:10 Part 10.
SPEAKER: In the past decade, a woman was being monitored for an expanding lesion in her right petrous bone. Her complaints that led to imaging included the history of migraine headaches with nausea and photophobia, intermittent ringing in the right ear, and right aural fullness.
SPEAKER: She also had complaints related to a contralateral ear on the non-lesional side in the form of tinnitus and intermittent swooshing sounds. Her audiogram was completely normal. Imaging showed the presence of a mass in her petrous bone. The same imaging had remained stable for three years without any symptoms. Her first consultation was two months after giving birth. And her primary goal was to bond with her new baby.
SPEAKER: She was not considering any surgical options at that time. The suspected diagnosis was chondrosarcoma. She remained asymptomatic despite gradual progression of her tumor. As the tumor progressed, we recommended surgical resection using an endoscopic endonasal transpterygoid approach. Because of significant pneumatization of the petrous bone, we considered an anterior transpetrosal approach too risky for CSF leakage.
SPEAKER: Since the patient was asymptomatic, she declined surgery. This continued for several years until the patient suddenly developed diplopia from a right abducens palsy, intermittent numbness in all three divisions of the right trigeminal nerve, and a feeling of aural fullness. She then agreed to undergo surgery. During the endoscopic transpterygoid approach, we encountered the mass that was much firmer than the common chondrosarcoma even though we had anatomic confirmation by navigation.
SPEAKER: The pathology team believed that we were only taking biopsies of dense fibrous tissue and must be outside the mass. We partially resected the lesion using scalpels and rongeurs, but did not pursue total resection due to its firm attachment to the carotid artery and cranial nerves. After the surgery, the patient's abducens palsy was resolved, but she developed a new right hypoglossal palsy.
SPEAKER: She was happy with the resolution of her double vision. We recommended radiation based on prior biological behavior of the lesion. But the radiation team declined because of lack of definitive diagnosis. Molecular markers for chondrosarcoma were not available at the time of the first operation. After an initial tissue examination yielding inconclusive results, the patient was kept under observation for nine months.
SPEAKER: During that time, evidence of regrowth into the surgical cavity was observed. The patient's symptoms also worsened with the recurrence of her right abducens palsy. Over the ensuing year, we remained in a state of uncertainty as the mass slowly fill the space created by the prior resection. After careful consideration, we recommended a repeat operation using the same surgical approach, but with a broader exposure given the tumor consistency.
SPEAKER: To provide an overview, we present the relevant endoscopic endonasal anatomical boundaries needed to access the lesion. This is known as Gardner's triangle. This outlines the structural boundaries that are imperative to understanding the endoscopic endonasal anatomy. The limits of Gardner's triangle are the periclinal internal carotid artery, the abducens nerve posterior medially, and the petroglyph synchondrosis inferiorly.
SPEAKER: We planned a repeat of the endoscopic transsphenoidal and transpterygoid approach to remove the right petrous tumor. During the second surgery, we removed portions of the mass using scalpel and CUSA. Chondrosarcoma was finally confirmed. However, we accidentally nicked the inferolateral wall of the cavernous sinus with a diamond bur, not just once but twice.
SPEAKER: During the second episode of bleeding, we saw some pulsatile bleeding, but remained unconvinced that the carotid artery was injured. Both times, the bleeding stopped with injection of Surgiflo. In retrospect, some of the hemostatic material entered the carotid artery and resulted in a distal embolic stroke. The patient woke up from surgery with left hemiparesis. Postoperative neurological examination revealed signs of neglect of the left side, right-sided facial palsy, and left hemiparesis.
SPEAKER: An MRI scan revealed embolic strokes on the right hemisphere, but the follow-up CT angiogram showed no evidence of dissection of vascular pathology. The patient was discharged to an inpatient rehabilitation facility three days after surgery with some mild left-sided neglect. On the 10th day after her surgery, she experienced profound and sudden epistaxis and was rushed back to our emergency department.
SPEAKER: We proceeded with stent coiling after a cerebral angiogram revealed a pseudoaneurysm on the inferior cavernous segment of the carotid artery. Two days later, a repeat cerebral angiogram showed occlusion of the cavernous segment of the carotid artery, reconstitution of the right supraspinal carotid via the ophthalmic artery, and robust left and right collaterals via the anterior communicating artery without venous delay.
SPEAKER: The patient was asymptomatic at this time. To restate our opinion, that the patient recovered from the majority of these insults in good condition is a testament to luck rather than proper knowledge, planning, or execution. The first misstep was delaying surgical intervention, even though tumor growth was evident, and the patient was still asymptomatic. The patient declined surgery against advice, but we went along with this for two years until she presented with neurological deficits.
SPEAKER: This was poor judgment on our part, since we could have made a far more convincing argument for early surgery. The second misstep was poor execution. One surgery should have been enough. And we should have completed resection of the mass on the first attempt. The anatomical information from navigation, the symptomatic and radiographic progression seen over time should have been sufficient to override the inconclusive results from pathology.
SPEAKER: The third misstep was poor execution at the second surgery. First off, injuring the carotid artery should have been avoided despite the anatomical distortion by scarring in the tumor. Second, and perhaps more importantly, with pulsatile bleeding from the area of the cavernous sinus, liquid hemostatic agents should not be used. As it happened, penetration of the agents into the carotid resulted in embolic strokes.
SPEAKER: Possibly, Surgicel fibrillar or crushed muscle should have been used instead. The fourth misstep was using CTA rather than cerebral angiography. This was born out of complication fatigue: the feeling that we had put the patient through so much unnecessary trauma that we needed to stop. This reluctance to pursue another invasive study pushed us to skip the proper study.
SPEAKER: We might have identified the pseudoaneurysm at that time prior to life threatening epistaxis. I received a backhanded compliment from my mentor earlier in my career at a morbidity and mortality conference. Quote, "Thank you so much for presenting this complication. Your colleagues seem to keep making the same mistakes over and over again. But you, on the other hand, make new complications that we never even knew were possible," unquote.
SPEAKER: Our patient is asymptomatic at this time, and her residual tumor has been treated with proton beam therapy. Her case has a permanent place in my cemetery of regrets.
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