Acoustic neuroma (vestibular schwannoma): surgical results on 240 patients operated on dorsal decubitus position.

OBJECTIVE: To evaluate the result of the surgical treatment of vestibular schwannoma (VS) operated in dorsal decubitus (mastoid position). METHOD: 240 patients with a VS underwent a retrosigmoid craniotomy for tumor resection in dorsal decubitus (mastoid position). The function of 7th and 8th cranial nerves was monitored during surgery and the opened internal auditory canal (IAC) was reconstructed using a vascularized dura flap, muscle and fibrin glue. RESULTS: Complete tumor removal was achieved in 99% of the cases, with a mortality of 1.6%. The facial nerve function was preserved in 85% of cases and hearing in 40% of the patients (with preoperative hearing) with tumors of up 1.5 cm in diameter. The incidence of cerebrospinal fluid leak was 5.8% and meningitis 2.9%. Venous air embolism was registered in 3% of cases; it was not associated to mortality. CONCLUSION: Surgical removal of VS in dorsal position has several advantages; the morbidity and mortality are very low.

Acoustic neuroma (vestibular schwannoma): surgical results on 240 patients operated on dorsal decubitus position

OBJECTIVE: To evaluate the result of the surgical treatment of vestibular schwannoma (VS) operated in dorsal decubitus (mastoid position). METHOD: 240 patients with a VS underwent a retrosigmoid craniotomy for tumor resection in dorsal decubitus (mastoid position). The function of 7th and 8th cranial nerves was monitored during surgery and the opened internal auditory canal (IAC) was reconstructed using a vascularized dura flap, muscle and fibrin glue. RESULTS: Complete tumor removal was achieved in 99 percent of the cases, with a mortality of 1.6 percent. The facial nerve function was preserved in 85 percent of cases and hearing in 40 percent of the patients (with preoperative hearing) with tumors of up 1.5 cm in diameter. The incidence of cerebrospinal fluid leak was 5.8 percent and meningitis 2.9 percent. Venous air embolism was registered in 3 percent of cases; it was not associated to mortality. CONCLUSION: Surgical removal of VS in dorsal position has several advantages; the morbidity and mortality are very low.

OBJETIVO: Avaliar o resultado do tratamento cirúrgico de pacientes portadores de schwannoma do vestibular (SV) operados em decúbito dorsal (posição de mastóide). MÉTODO: 240 pacientes foram submetidos a craniotomia retrosigmóide na posição de mastóide. A função do VII e VIII nervos cranianos foi monitorizada durante a cirurgia e a reconstrução da abertura do conduto auditivo interno foi realizada com retalho vascularizado de dura-mater, músculo e cola de fibrina. RESULTADOS: A exérese foi completa em 99 por cento dos casos, com mortalidade de 1,6 por cento. Houve preservação da função do nervo facial em 85 por cento dos casos e da audição em 40 por cento dos pacientes com audição prévia e tumores menores de 1,5 cm. A incidência de fístula liquórica foi 5,8 por cento e meningite 2,9 por cento. Embolia gasosa foi registrada em 3 por cento dos casos, não associada à mortalidade. CONCLUSÃO: O tratamento cirúrgico dos SV utilizando-se a posição de mastóide tem várias vantagens, com baixa morbidade e mortalidade.

Surgical treatment of Menière's disease.

Surgical treatment is used only for patients with Menière's disease in cases that do not respond to medical therapy. At the present time, the endolymphatic sac shunt operation is performed in cases where the auditory threshold is fluctuant around 30 dB. When the auditory threshold is between 40 and 70 dB we use the vestibular neurectomy by the retrosigmoid approach. In patients with Menière's disease with profound hearing loss the translabyrinthine neurectomy is used. The advantages of the vestibular neurectomy by the retrosigmoid approach compared to the retrolabyrinthine and middle fossa approaches will be described.

Vascular decompression surgery for severe tinnitus: selection criteria and results.

Seventy-four patients were operated on within a period of 10 years to treat incapacitating tinnitus; 72 underwent microvascular decompression (MVD) of the intracranial portion of the auditory nerve, and 2 underwent section of the eighth nerve close to the brain stem. Of those who underwent MVD, 2 had no change in symptoms and later also underwent section of the eighth nerve near the brain stem. Two patients did not return for follow-up. Of the 72 remaining patients, 13 (18.1%) experienced total relief from tinnitus, 16 (22.2%) showed marked improvement, 8 (11.1%) showed slight improvement, 33 (45.8%) had no improvement, and 2 (2.8%) became worse. The patients who experienced total relief and those who showed marked improvement had experienced their tinnitus for an average of 2.9 years and 2.7 years, respectively; those who showed slight improvement and those who had no improvement had experienced their tinnitus for a longer time before the operation (mean, 5.2 and 7.9 years, respectively). Of the 72 patients who were operated on and followed, 32 were women. Of these, 54.8% experienced total relief from tinnitus or marked improvement, while only 29.3% of the men showed such relief or improvement. Selection of the patients for operation was mainly based on patient history and, to some extent, on auditory test results (brainstem auditory evoked potentials [BAEP], acoustic middle ear reflexes, and audiometric data).

Microsurgical anatomy of VII and VIII cranial nerves and related arteries in the cerebellopontine angle.

The relationships of VII and VIII cranial nerves and related arteries are reviewed in 26 preparations by microdissection techniques. These vessels may be grouped in large (AICA, PICA), medium (LA, SA, CSA, RPI) and small calibre (vasa nervorum, radicular and medullar branches). The importance of these structures in acoustic neuroma surgery, vestibular neurectomy and cross-compression syndromes is discussed. "Vascular loops" and "elongated arteries" are normal structures present at birth.