Surgery is performed with the patient in dorsal decubitus with the head rotated to the opposite side. A semicircular skin incision from the temporal region, 4 cm above the zygomatic arch, passing 3 cm behind the ear, extending 2 cm behind the mastoid tip is performed (Fig. 19.10a). To avoid postoperative CSF leak, a skull base reconstruction technique utilizing fascia/muscle flaps was developed. The temporalis muscle fascia is cut and dissected with the mastoid periosteum, the cranio-cervical fascia, and the sternocleidomastoid muscle that is detached from its insertion. These structures form a large vascularized muscle/fascia flap that is rotated back at the end of surgery to cover the entire surgical field. The temporal muscle is dissected in the anterior direction and used to cover the dura mater, as a vascularized muscle, at the end of the operation. The cortical bone of the mastoid is drilled out exposing the antrum, tegmen mastoid, and sinus plate. The labyrinth block and the facial nerve canal are identified. These canals are not opened. Two trepanations above and two below the sigmoid sinus are placed, and with a high-speed drill, a craniotomy exposing the middle fossa and the posterior fossa (retrosigmoid) is cut (Fig. 19.10b). The superior petrosal, the sigmoid, and the transverse sinuses are exposed. The retrofacial mastoid cells down to the jugular bulb are removed. The dura mater anterior to the sigmoid sinus is exposed (Fig. 19.10c). The zygomatic and supra-labyrinthine cells are removed maintaining the semicircular canals and middle ear intact. The superior petrosal sinus is coagulated and ligated between two stitches. The dura mater is incised anterior to the sigmoid sinus and parallel to the middle fossa floor (Fig. 19.10d). The superior petrosal sinus is cut. The tentorium is severed initially perpendicular to the superior petrosal sinus in a length of 2 or 3 cm and then medially, parallel to the transverse sinus for an additional 3 cm. This maneuver allows a wide exposure of the cerebellum separating it from the posterior aspect of temporal lobe like “opening a book” (Fig. 19.11a). Care should be taken to preserve the vein of Labbé which has a variable anatomy and usually enters the transverse sinus 10 mm before its junction with the sigmoid sinus. Preoperative evaluation of the venous anatomy is necessary in planning this approach. The tentorium incision is continued up to the incisura where the IV nerve is exposed and preserved (Fig. 19.11b). Some small basal temporal lobe bridge veins are coagulated and cut allowing wide subtemporal exposure. Two brain spatulas are placed supporting the temporal lobe and the cerebellum exposing the entire petroclival region from the III nerve up to VII and VIII nerves (Fig. 19.11c). Usually the trigeminal nerve can be seen displaced posterior and superiorly. The tumor is devascularized by bipolar coagulation of its dural insertion. Intracapsular, piecemeal tumor resection using the ultrasonic aspirator is the next surgical step. Tumor debulking allows dissection of tumor capsule from the nerves and basilar, superior cerebellar, and posterior cerebral arteries. The abducens nerve is very thin and fragile. Dorello’s canal is located medially to the VII and VIII cranial nerves. This region should be approached only after wide resection of the tumor. Tumor extension into the posterior portion of the cavernous sinus is resected following the trigeminal nerve. All infiltrated petrous and clivus bone are removed with a diamond drill. After total removal (Fig. 19.11d, e), the dura mater is closed in watertight fashion or with fascia graft and fibrin glue. The aditus and antrum are closed with a muscle plug, and the temporalis muscle is flap rotated to cover the entire exposed dura mater. The fascia-muscle flap (temporalis, cranio-cervical fasciae, and sternocleidomastoid muscle) is sutured in its original position, and the skin is closed.