Vestibular Schwannoma Surgery by Mustafa K. Baskaya & G. Mark Pyle & Joseph P. Roche

Author:Mustafa K. Baskaya & G. Mark Pyle & Joseph P. Roche
Language: eng
Format: epub
ISBN: 9783319992983
Publisher: Springer International Publishing

Surgical Technique

Microsurgical treatment of a VS via the MCF approach involves three main parts: exposure of the lesion, removal of the lesion, and reconstruction of the skull base. Each will be discussed in detail including common variations in surgical technique.

Prior to bringing the patient back to the operative suite, the patient’s ear and a secondary site should be marked with the patient’s participation to ensure that the side and site of the proposed procedure are known and agreed upon. If an abdominal fat graft is to be harvested, this site should be marked as well. A conversation is held with the anesthesiology team to discuss the case including the need to be able to monitor facial nerve function. Long-term muscle relaxants should be avoided during the induction of anesthesia and intubation , as these may interfere with facial nerve electromyography and facial movement visualization. The presence of muscular twitches should be confirmed prior to the skin incision if non-depolarizing muscle relaxants were utilized or if multiple boluses of a depolarizing agent were required during the induction of general anesthesia. If intraoperative BAER monitoring is to be utilized, this equipment should be in the room with appropriate personnel. Confirmation that critical equipment is available and in working order is performed prior to bringing the patient to the operating theater. At a minimum, the facial nerve monitor and operating microscope should be checked. While equipment such as an image guidance system, auditory evoked potential (AEP) monitors, imaging display systems are helpful, the operating microscope and facial nerve monitor are required for safe surgery.

Once general anesthesia has been induced and the appropriate venous and arterial access lines have been placed and secured, the bed is turned away from anesthesia. If the room is large, 180° is preferable but if the room is small, 90–120° is typically sufficient. By turning 180°, the surgeon sits at the head of the bed with the surgical assistant and observer on either sides of the bed. If CSF diversion is to be utilized, this catheter is typically placed at this time. It is generally easier to place the catheter prior to drainage of CSF from the CPA cistern that occurs during tumor removal.

The patient is placed in a supine position (Fig. 3.10a) (Video 3.1). The head is either secured with a skull clamp using 3-point fixation or placed into a special gel pad with a cutout to protect the contralateral ear (Fig. 3.10b) (Video 3.1). If a skull clamp is used, the single point is aligned with the contralateral midpupillary line near the hairline of the forehead and between 60 and 80 pounds per square inch of pressure is used to secure the skull. The head is turned such that the index ear is facing up and the side of the skull is as parallel to the floor as possible. The chin is tucked but at least two fingerbreadths of space between the clavicle and chin is maintained to prevent complete occlusion of the contralateral internal jugular vein that can impede cranial venous drainage (Fig.

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