RESUMEN

Trigeminal schwannomas are rare nerve sheet tumors that represent the second most common intracranial site of occurrence after vestibular nerve origins. Microsurgical resection of giant dumbbell-shaped trigeminal schwannomas often requires complex skull base approaches. The extradural transcavernous approach is effective for the resection of these giant tumors involving the cavernous sinus. The patient is a 72-year-old man with headache, dizziness, imbalance, and cognitive decline. Neurological examination revealed left-sided sixth nerve palsy, a diminished corneal reflex, and wasting of temporalis muscle. Magnetic resonance imaging (MRI) showed a giant homogeneously enhancing dumbbell-shaped extra-axial mass centered within the left cavernous sinus, Meckel's cave, and the petrous apex, with extension to the cerebellopontine angle. There was a significant mass effect on the brain stem causing hydrocephalus. Computed tomography (CT) scan showed erosion of the petrous apex resulting in partial anterior autopetrosectomy ( Figs. 1 and 2 ). The decision was made to proceed with tumor resection using a transcavernous approach. Gross total resection was achieved. The surgery and postoperative course were uneventful, and the patient woke up the same as in the preoperative period. MRI confirmed gross total resection of the tumor. The histopathology was a trigeminal schwannoma, World Health Organization (WHO) grade I. The patient continues to do well without any recurrence at 15-month follow-up. This video demonstrates important steps of the microsurgical skull base techniques for resection of these challenging tumors. The link to the video can be found at https://youtu.be/TMK5363836M.

RESUMEN

Because of their proximity to adjacent vital structures, and deep and narrow operative field in the surrounding compact bony structures, tumors located in the clival or petroclival regions represent a formidable technical challenge to neurosurgeons. Between April 1990 and May 1996, 25 patients(eight males and 17 females with a mean age of 44 years), harboring clival or petroclival tumors underwent surgery in our department involving the posterior transpetrosal transtentorial approach. The median follow-up period was 24 months. A total of 28 operations were performed ; in three cases, these involved two stages, in which different approaches were used. The surgical pathology included 15 meningiomas, seven neurinomas(four acoustic and three trigeminal), and one case each of myxoid chondrosarcoma, chondroid chordoma, and paratrigeminal epidermoid. Tumor size ranged from 2 to 8cm ; 16 were larger than 4cm. According to the extent of petrous resection, three different approaches were used ; retrolabyrinthine in ten cases, translabyrinthine in four, and transcochlear in eleven. The superior petrosal sinus was always sacrificed and the tentorium completely cut. Gross total removal was accomplished in 13 cases, and subtotal removal in 12. The causes of incomplete removal included cavernous sinus invasion in four cases, severe adhesion to the brain stem in two, extremely high consistency and vascularity of the tumor in two, insufficient exposure to the tumor in two, and unexpected residual tumors seen in two cases on postoperative MRI. There was no operative mortality in this series and the most common complication was cranial nerve palsy, which occurred in 15 cases. Other complications included hemiparesis in two cases, CSF leakage in two and an epidural hematoma in one. The authors conclude that the posterior transpetrosal transtentorial approach is advantageous for resecting petroclival tumors because, by avoiding unnecessary brain retraction, it significantly reduces the risk of postoperative complications, and helps provide shorter access and wider exposure of the lesion.

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RESUMEN

The authors have treated eight cases of trigeminal neurinomas for the past thirteen years. We have been treating these tumors in accordance with the principle of radical resection through one-staged operation. Three were male and five were female. The age ranged from 25 to 56 years with the mean age of 41.5 years. One was a case of von Recklinghausen's disease. Topographically, the tumors were mainly located within the middle fossa in two cases, within the posterior fossa in two, and extended both supra- and infratentorially in four cases. Facial pain and hearing disturbance were the main symptoms and various other symptoms such as focal seizure, hemiparesis, gait disturbance, symptoms of increased intracranial pressure and visual disturbance were also noted. Surgical operations were performed in all cases. As a surgical approach, either transpetrosal-transtentorial or orbitozygomatic-infratemporal route was employed. The choice of the better approach depends on the topography of the tumor. Total removal was performed in all cases. Only one case, which was an early one in this series required second operation to remove the tumor completely. In one case, the tumor recurred five years after the operation. There has been no operative mortality, but the injury or permanent damage to the trigeminal branches was inevitable in many cases. Surgical results were excellent in three, good in four, and fair in one case.

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