Name:
Resection of a recurrent pineal region teratoma via a posterior interhemispheric transcallosal approach
Description:
Resection of a recurrent pineal region teratoma via a posterior interhemispheric transcallosal approach
Thumbnail URL:
https://cadmoremediastorage.blob.core.windows.net/9a2eec74-fb01-4e0e-9549-44da47e77f0b/videoscrubberimages/Scrubber_343.jpg
Duration:
T00H10M38S
Embed URL:
https://stream.cadmore.media/player/9a2eec74-fb01-4e0e-9549-44da47e77f0b
Content URL:
https://cadmoreoriginalmedia.blob.core.windows.net/9a2eec74-fb01-4e0e-9549-44da47e77f0b/21-34.mp4?sv=2019-02-02&sr=c&sig=t7BAo6QsBgJwQJezuR%2FiPboxfAEnUaapaHxJynD4aX4%3D&st=2024-04-30T03%3A21%3A04Z&se=2024-04-30T05%3A26%3A04Z&sp=r
Upload Date:
2021-10-27T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
[MUSIC PLAYING]
SPEAKER 1: In this video, we describe a posterior interhemispheric transcallosal approach for resection of a recurrent pineal region teratoma. The patient was a 6-year-old male who initially presented to an outside hospital with headaches and was found to have a pineal region mass with obstructive hydrocephalus. He underwent an endoscopic biopsy and VP shunt placement with subsequent placement of two additional Ommaya catheters into cystic components of the mass.
SPEAKER 1: The diagnosis was consistent with the mixed germ cell tumor, and the patient underwent two cycles of chemotherapy. Then his exam declined and subsequent imaging demonstrated rapid enlargement of the mass. He was transferred for further management, and upon arrival he was noted to be opisthotonic, with the decorticate posturing, inability to open his eyes, tonic gaze deviation to the left, and decreased hearing, though his pupils were equal and reactive and he was able to respond verbally.
SPEAKER 1: The patient's initial imaging demonstrated a large, heterogeneous contrast-enhancing mass with solid and cystic components exerting significant mass effect on the tectum and dorsal brainstem. Once stabilized, the patient was taken to the OR for resection of the mass. Three primary approaches to the pineal region and posterior third ventricle have been described-- the supracerebellar infratentorial approach, the occipital interhemispheric transtentorial approach, and the posterior interhemispheric transcallosal approach which can be performed utilizing an intervenous or paravenous variance.
SPEAKER 1: Each tumor in this region is unique. In choosing the optimal approach, should take several considerations into account. The dimensions of the tumor, particularly in the anterior, posterior, and rostral-caudal axes. Proximity to other neurovascular structures such as the corpus callosum, midbrain, superior cerebellum, thalamus, and deep venous system. The angle of the tentoriam.
SPEAKER 1: The consistency of the tumor. And the individual surgeon's training, experience, and comfort level. For this particular tumor, the intervenous variant of the posterior interhemispheric transcallosal approach was chosen. Notably, there's a natural separation of the fornices posteriorly, where they diverge into the forniceal crura. The fornices are always lateral to the internal cerebral veins at this level.
SPEAKER 1: Therefore, by maintaining a plan of dissection between the two ICVs, the fornices remain protected while accessing the velum interpositum, the roof of the third ventricle. The posterior interhemispheric approach has a number of advantages, including wide access to the surrounding structures and early identification and control the ICVs. This expanded corridor is particularly useful for mature teratomas which have elements of bone, cartilage, and muscle that are not easily removed with an ultrasonic aspirator and which must often be removed piecemeal.
SPEAKER 1: This can be challenging when working, in a deep space with a long, narrow corridor. Similarly, the resection of bloody tumors, such as pineal plastomas, may be facilitated by an expanded corridor, whereas pinas and gliomas are often easily removed with an ultrasonic aspirator and are amenable to a variety of surgical approaches. The posterior interhemispheric approach is particularly useful in tumors with a long rostral caudal axis and if the upper aspect of the tumor is immediately underneath the corpus callosum.
SPEAKER 1: Additionally, this approach avoids prone positioning and is relatively ergonomic, allowing two surgeons to work across from each other and utilize the four-hand technique. Disadvantages of the posterior hemispheric approach include a potential blind spot underneath and behind the splenium of the corpus callosum, the need to sometimes sacrifice a cortical bridging vein, and the need for brain relaxation in order to avoid excessive retraction on the medial hemisphere, which can result in postoperative weakness.
SPEAKER 1: In order to perform the posterior transcallosal approach, one option is to place the patient in a lateral position of the ipsilateral hemisphere in the dependent position to facilitate retraction by gravity. However, we prefer to place the patient in the supine position with the neck flexed in order to orient the vertex to the ceiling. We find that this provides natural orientation for the surgeon and facilitates involvement by the assistant surgeon using the four-hand technique.
SPEAKER 1: Once the patient was positioned, the midline was marked and frameless stereotactic navigation was used to identify trajectories to the anterior and posterior aspects of the tumor. A bi-parietal zig-zag incision was then marked. The skin was incised and self-retaining retractors were placed. Burr holes were made on either side of the midline anteriorly and posteriorly, and a biparietal craniotomy was performed following dissection of the epidermal space.
SPEAKER 1: Gelfoam was placed over the sagittal sinus, and the dura was opened on the right in a C-shaped fashion and flapped toward the midline. The microscope is brought into the field. Sutures were placed on the falx and tied to epidural tack-up holes in the contralateral parietal bone in order to mobilize the falx and expand the surgical corridor. Microsurgical dissection techniques were used to dissect the interhemisphere fissure down to the pericallosal vessels.
SPEAKER 1: Cottonoids were placed to protect the medial surface of the hemisphere. Fixed retractors were not used at all during the case. The anterior and posterior limits of the needed callosotomy were then defined with frameless stereotactic guidance, and the corpus callosum was open to the right of midline. Immediately upon coming through the thinned-out corpus callosum, the tumor capsule was encountered. The capsule was opened and the ultrasonic aspirator was used to begin to debulk the tumor, which appeared to be filled with thick mucinous tissue in some regions, whereas in other regions we encountered areas of cartilage, squamous epithelium, and various teratomatous elements.
SPEAKER 1: Firm areas of the tumor cannot be removed effectively with the aspirator, and sharp dissection was required. The tumor was noted to be adherent to the internal cerebral veins. The left ICV was identified, and sharp dissection was used to release it from the tumor, taking care not to injure the vessel itself. Similarly, the right ICV was identified and sharp dissection was again used to release it from the tumor.
SPEAKER 1: Once the internal cerebral veins were released, the ultrasonic aspirator was then used to debulk the tumor where possible. Upon releasing the ICVs, we were able to complete our circumferential dissection of the tumor and remove it as one piece. Upon removal of the tumor, CSF could be seen arising from the cerebral aqueduct, which appeared patent. The wound was copiously irrigated and the hemostasis was obtained.
SPEAKER 1: All hemostatic agents were removed from the resection cavity. A watertight dural closure was performed. The bone flap is then replaced and secured with titanium plates and screws and the galeal and skin were closed in layers. Pathology was consistent with a mixed germ cell tumor. The patient's neurological exam improved quickly postoperatively.
SPEAKER 1: He was discharged home on postoperative day number 8, and did not require further adjuvant treatment. However, a surveillance scan 2 years later demonstrated an asymptomatic recurrence of the tumor. Imaging demonstrated diffusion restricting nodules at the site of the prior resection in the region of the posterior third ventricle and aquaduct. Contrast-enhanced imaging demonstrated one nodule of tumors to the right of midline, with another in the region of the aqueduct and a third underlying the splenium.
SPEAKER 1: Tumor markers were negative, suggesting that the recurrence was likely a mature teratoma. The patient was therefore taken back to the operating room for resection of the mass. The patient was positioned in a similar fashion as during his original surgery. The incision was reopened, and the biparietal bone flap was removed. The dura was opened medial to the prior suture line.
SPEAKER 1: However, the pia was quite adherent to the dura, and we noted a small chronic subdural membrane. Therefore, the microscope is brought into the field, the dura was opened with an 11 blade, and microsurgical dissection was performed to separate the dura from the chronic subdural membrane. At the midline, the membrane was opened and a pial dissection was performed to separate the pia from the interhemispheric fissure.
SPEAKER 1: The old callosotomy was identified and opened. This led us into the ventricle where the first tumor nodule was identified overlying the aqueduct, consisting primarily of whorls of hair. The tumor seemed to be arising from the inferior aspect of the junction of the ICVs and the vein of Galen.
SPEAKER 1: The capsule of the tumor was bipolared and cut with microscissors, leaving the vein intact. Eventually, we were able to work around the tumor and hand it off to field, exposing the patent cerebral aqueduct.
SPEAKER 1: Gelfoam was placed over the aqueduct to prevent rundown of blood products. Just above that area, there was the second nodule of tumor with the classic epidermoid pearly appearance which was dissected out and removed. Finally, image guidance was used to identify the third nodule of tumor near the splenium of the corpus callosum.
SPEAKER 1: This nodule had a tough, leathery capsule and appeared to be attached to the adjacent vein. Microbipolar was used to coagulate the capsule and microscissors were used to transect it, staying just above the vein. Laterally, vessels entering the capsule from the choroid plexus in the atrium of the right lateral ventricle were coagulated and cut. Eventually, we were able to mobilize the whole encapsulated tumor and resect it away from the veins, leaving them intact.
SPEAKER 1: This was handed off as a separate specimen. The thick, leathery capsule was opened, and sebaceous material was identified. The cavity was inspected under the microscope, and anything suspicious for residual tumor was removed. The wound was copiously irrigated and hemostasis was obtained. All the hemostatic agents were removed except for a small piece of gelfoam on the vein of Galen.
SPEAKER 1: A watertight dural closure was obtained with the incorporation of a bovine pericardial patch graft. The bone flap is resecured with titanium plates and screws, and the gileal and skin will closed with absorbable sutures. Postoperative imaging demonstrated a gross-total resection. Pathology was consistent with a mature teratoma. The patient's neurological exam remained intact postoperatively, and he was discharged on postoperative day number 4.
SPEAKER 1: At his most recent follow-up 20 months after his second resection, he was noted to have an intact exam with full extraocular movements. Follow-up imaging at that time revealed postoperative changes without evidence of recurrence to date. Thank you.