Name:
10.3171/2022.1.FOCVID21226
Description:
10.3171/2022.1.FOCVID21226
Thumbnail URL:
https://cadmoremediastorage.blob.core.windows.net/e852fe2b-d48f-43e4-b7cd-c76fa39aceb0/videoscrubberimages/Scrubber_168.jpg
Duration:
T00H09M26S
Embed URL:
https://stream.cadmore.media/player/e852fe2b-d48f-43e4-b7cd-c76fa39aceb0
Content URL:
https://cadmoreoriginalmedia.blob.core.windows.net/e852fe2b-d48f-43e4-b7cd-c76fa39aceb0/21-226.mov?sv=2019-02-02&sr=c&sig=HMvCxKfdEfr0dM7n3tt9atwzocv186bEloq%2BR%2BtV9t4%3D&st=2025-02-05T09%3A48%3A37Z&se=2025-02-05T11%3A53%3A37Z&sp=r
Upload Date:
2022-02-10T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
[MUSIC PLAYING]
SPEAKER 1: This video shows a combined petrosal approach for resection of a petroclival meningioma. The patient was admitted for headache, dysphagia, and left facial pain. The MRI showed a left petroclival meningioma that progressively increased on radiological follow-up and was associated with worsening of neurological symptoms. The combined petrosal approach was chosen for different reasons.
SPEAKER 1: Firstly, the inferior limit of the tumor was lower than the internal acoustic meatus. Secondly, anterior petrosal approach does not provide an optimal control over the seventh and eighth cranial nerves in the cisternal segment. Thirdly, the combined petrosal approach with posterior transposition of sigmoid sinus offers an upward line of sight, which provides adequate exposure of the superior aspect of the tumor, third cranial nerve, and posterior communicating artery.
SPEAKER 1: Finally, this approach provides multiple lines of sight, each of which can be used for optimal dissection of the various cranial nerves and major vessels. The audiogram showed a serviceable hearing. For this reason, a retrolabyrinthine petrosectomy was preferred. MRI did not show any brainstem edema. The vein of Labbé presents a regular anatomical confirmation. Preoperative CT scan is helpful in the assessment of the bony anatomy, including tumor calcification, pneumatization of the petrous apex, and the retromeatal space.
SPEAKER 1: It is also important to evaluate a possible dehiscence of the middle fossa floor over the geniculate ganglion as well as the dehiscence at the level of the carotid canal in order to reduce the risk of injury of these structures during the approach. Finally, we evaluate also the height of the jugular bulb in relation to the internal acoustic canal. Preoperative angiography allows to evaluate the vascularization of the tumor.
SPEAKER 1: This sequence shows a blush coming from the ascending pharyngeal artery and also from the dural branches of the internal carotid artery, represented by the infralateral trunk and meningohypophyseal trunk. Embolization, through coils at the level of the ascending pharyngeal artery, performed the day before surgery, enables to reduce significantly the intraoperative bleeding. The patient is put in supine position with the head fixed in a three-pin skull's clamp and rotated 70 to 80 degrees to the contralateral side.
SPEAKER 1: A C-shaped skin incision is made starting from the tip of the mastoid and encircling the approximate location of the temporalis muscle. Cranial nerves and somatosensory and motor evoked potentials are monitored. Neuronavigation is used to locate the transverse-sigmoid junction. The first surgical step is represented by the interfascial dissection of the temporalis muscle in order to release the skin flap.
SPEAKER 1: Once the fat pad is found an interfascial dissection is performed. And then the temporal muscle is elevated in a retrograde fashion subperiosteally. The monopolar is used to detach the sternocleidomastoid muscle from the superior knuckle line. Digastric muscle is also detached. At the end of this procedure, these muscles are retracted inferiorly.
SPEAKER 1: The posterior margin of the external acoustic canal is progressively found and also the root of the zygoma. A burr hole is performed at the level of the transverse-sigmoid junction and position of the sinus is confirmed by intraoperative Doppler. Another burr hole anteriorly performed at the level of the temporal bone. And then a one-piece temporal and retrosigmoid sigmoid craniotomy is performed.
SPEAKER 1: Using a craniotome without footplate and a bone scalpel, a cosmetic mastoidectomy is progressively obtained. Using cutting and diamond burrs, mastoidectomy is performed with progressive identification of the sinodural angle and labyrinthine block. Skeletonization of the sigmoid sinus is done by diamond burr and rongeur. Medial fossa is then flattened and then we progressively identify foramen spinosum.
SPEAKER 1: Medial meningeal artery is coagulated and cut. Peeling of the dura is performed with progressive identification of GSPN, V3, arcuate eminence, and petrous reach that are the limits of the Kawase rhomboid. In case of tense brain, retrosigmoid dura is open to assist the lower cranial nerve system and release the CSF. The drilling of the Kawase rhomboid should start in the safest region, which is next to V3, where a hole is created.
SPEAKER 1: Then this cavity is progressively enlarged in the posterior and posterolateral direction under constant irrigation until the dura of the posterior fossa is exposed. The anterior petrosectomy is then extended inferiorally and posteriorly until reaching cortical ivory bone surrounding the cochlea and the superior semicircular canals. The temporal dura is incised. Another incision is made more laterally and posteriorly to identify the vein of Labbé and avoid its injury.
SPEAKER 1: Subsequently, the dura is used to retract the sinus. Patency of the eventual tentorial venous channels is verified using intraoperative Doppler. Presigmoid dura is progressively open in a semicircle fashion running anteriorly below the SPS. Tentorium resection starts with a posterior cut toward the free edge. Then, an anterior cut is performed, starting at the level of the porus trigeminalis.
SPEAKER 1: The dura is very thick and infiltrated by the tumor. A piece of infiltrated tentorium is then progressively removed with a Kerrison punch in a piecemeal fashion allowing wide exposure of the superior aspect of the tumor. Then, the dura of the lateral aspect of the porus trigeminalis in mega scale is also opened, exposing V3.
SPEAKER 1: The two-forceps technique is used to preserve the arachnoidal plane around neurovascular structures. The fourth cranial nerve is visualized under the tentorium. Ultrasonic aspirator is used to perform a progressive debulking of the tumor, alternated to gentle bimanual dissection. This technique is mandatory to preserve basilar artery perforators located in this delicate area.
SPEAKER 1: Debulking of the tumor alternates with the two- forceps techniques. After identification of the basilar artery, low aspiration and microscissors are utilized to progressively mobilize the tumor and dissect it freely from these vessels. This delicate procedure is done under high magnification in order to cut safely the small arachnoidal bridges connecting the tumor to the basilar artery and its perforators.
SPEAKER 1: The dorsal surface of tumor is also dissected and mobilized using the same technique. In case of brainstem edema and tight adherence to the brainstem, remnants of the tumor should be left behind to avoid any injury of these perforators. Progressively, the third cranial nerve is identified and dissected free from the tumor and also the sixth cranial nerve going toward Dorello’s canal.
SPEAKER 1: The temporal dura is then reapproximated with 5-0 dural stitches. Then a thin layer of bone wax was used to seal the middle here. Pericranium is applied over the tegmen tympani and fixed with some glue. Abundant abdominal fat tissue is positioned into the surgical cavity in order to fill the dead space created by the combined petrosal approach.
SPEAKER 1: Fibrin glue is used in order to secure the fat. A continuous running suture is performed over the temporal and retrosigmoid dura in order to obtain a satisfying dura closure. The mastoid cortical bone and the bone flap were replaced and attached with miniplates. Postoperative CT scan does not show any postoperative complication. Postoperative MRI shows the near-total resection of the meningioma with a small residue in the posterior part of the cavernous sinus.
SPEAKER 1: During the postoperative course, the patient presented a partial fourth cranial nerve palsy with a slight diplopia while looking down that recovered completely after 3 months, and a slight hearing decrease due to otitis media, which was completely resolved after 6 months.
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