Name:
Endoscopic-assisted microsurgical resection of giant vestibular schwannoma in semi-sitting position
Description:
Endoscopic-assisted microsurgical resection of giant vestibular schwannoma in semi-sitting position
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Duration:
T00H08M33S
Embed URL:
https://stream.cadmore.media/player/64fafe2f-bbf2-4f30-87d0-e7a72235a069
Content URL:
https://cadmoreoriginalmedia.blob.core.windows.net/64fafe2f-bbf2-4f30-87d0-e7a72235a069/21-76.mp4?sv=2019-02-02&sr=c&sig=h3C%2FpifYC4HAr6AQshPjjSYrMC04sDXF0dgr%2BEWqZzw%3D&st=2025-02-22T06%3A39%3A26Z&se=2025-02-22T08%3A44%3A26Z&sp=r
Upload Date:
2021-10-27T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
[MUSIC PLAYING]
SPEAKER: This video demonstrates an endoscopic-assisted microsurgical resection of giant vestibular schwannoma in semisitting position. A 28-year-old female patient presented with a 1-month history of progressive left tinnitus and a hearing impairment. The patient facial function was normal before operation. Audiometric examination reveals hearing loss in the left ear. The MRI showed a homogeneously enhance the tumor in the left cerebellopontine angle, extending into the internal acoustic canal.
SPEAKER: The brainstem was compressed by the tumor. The tumor diameter is approximately 4.4 cm, can be graded as a T4b according to the Hannover classification system. Preoperative scan review that the IAC was enlarged. No enlarged emissary or high jugular bulb was observed in the skin. The x-ray on the review cervical instability, indicating a reduced potential risk of a neck injury during head positioning.
SPEAKER: For resection of this type of large tumor, we routinely used the retrosigmoid approach and put the patient in semisitting position. The advantages of semisitting position are as follows. The cerebellum can be relaxed fully after cerebrospinal fluid is released. Good brain relaxation can be achieved to maximize the surgical exposure. And a clean and bloodless operative field can be easily obtained in this position.
SPEAKER: The use of bipolar calculation for hemostasis can be reduced to avoid damaging the nerves. Before surgery, patient was examined using the transesophageal echocardiography to rule out the patent foreman ovale. Continuous interoperative monitoring was performed with a precordial Doppler echocardiography, TEE, and right atrium catheterization to facilitate early detection and the intervention for venous air embolism.
SPEAKER: We also use SEP and MEP of the extremity, facial MEP, and facial stimulation to monitor neurological function during surgery. We use the curved linear incision behind the ear so margins of the transverse sinus and sigmoid sinus were exposed. The dura was incised in a C-shaped fashion. After the dura was open and turned medially, the CSF was drained from the cerebellomedullary system.
SPEAKER: Here, we use the facial stimulation polar to stimulate the dorsal side of the tumor to exclude the presence of the facial nerve on the surface of tumor. Here, we use a CUSA for intracapsule debulking of the tumor, creating a working space for subsequent procedure. The dura of the posterior wall IAC was removed with an arc-shaped excision.
SPEAKER: The bone was progressively removed with a high-speed diamond drill for exposure of the tumor extending into the IAC. To prevent nerves from heating, irrigation was necessary to cool the bone during drilling. Here, we also use a stimulator to exclude the presence of the facial nerve. In the area of the fundus, we carefully use the right-angle detector to remove the tumor in piecemeal fashion.
SPEAKER: If it is difficult to remove the tumor within the IAC, the posterior wall can be further removed to expose the tumor. The tumor adhering to the facial nerve should be meticulously dissected. Here, we identify the facial nerve by using the stimulator.
SPEAKER: Microsurgical dissection was carefully performed to dissect the tumor and the capsule membrane. We try to keep the tumor capsule membrane intact for preservation of the facial nerve. Here, we can see that the assistant surgeon continuously irrigates the operative field with a saline solution so that a clean and bloodless operative view can be easily obtained. This helps the primary surgeon avoid using suction to remove the blood.
SPEAKER: And it enables dissection of the tumor using two microforceps in both hands. We use the tumor- holding forceps to hold the tumor and another forceps to peel out the capsule membrane from the tumor. During dissection, attention should be paid to the electromyographic response of the facial nerve to prevent the injury to the nerve.
SPEAKER: Constant use of a stimulator to confirm the position of the facial nerve is necessary. The use of CUSA is a quick and easy way to debulk tumors. Here is the root entry zone of the facial nerve on the brainstem. We also identify that the course of the facial nerve was at the anterior and superior side of the tumor.
SPEAKER: The strongest adherence between the tumor and the facial nerve in the vicinity of IAC. Therefore, this part of the tumor and the capsule must have carefully dissected. Hence, a subcapsular resection of tumor ensured that the facial nerve was not damaged. In this case, it was difficult to distinguish the facial nerve from the tumor.
SPEAKER: And the facial nerve was dispersed and flattened by the tumor. But the surgical cleavage plane was present. In cases where the facial nerves is membranous and not distinguishable from the tumor, there is no cleavage plane, the surgeon should determine if there is a residual thin layer of the tumor on the facial nerve to preserve the facial nerve function.
SPEAKER: [NO AUDIO] The bleeding site near the facial nerve can be comprised by Gelfoam or Surgicel for hemostasis.
SPEAKER: Bipolar coagulation should be avoided to prevent any injury to the facial nerve. Here, we evaluated the IAC using an endoscope and found a small amount of residual tumor within the IAC. We carefully use a right-angle dissector to remove the residual tumor. Finally, the tumor was completely removed, and the facial nerve was intact. The posterior wall of the IAC was sealed using a piece of muscle with fibrin glue.
SPEAKER: Postoperative MRI revealed complete tumor resection. The postoperative facial nerve function of the patient was House-Brackmann grade I at 3-months follow-up. In conclusion, in the semisitting position, a wide and clear operative field can be obtained. And the two-handed microsurgical dissection technique can be employed for the vestibular schwannoma removal. In addition, the use of bipolar coagulation can be reduced. Those advantages are conducive to the facial nerve preservation.
SPEAKER: Endoscope can help remove residual tumors in the IAC. This operation follows the "Samii's principle" in the vestibular schwannoma surgery. We appreciate the guidance of the Professor Madjid Samii.
