Surgical results in 254 cases of acoustic tumors operated on by the same neurosurgeon (T.S.) were reported. Based on the tumor size in the CP-angle cistern, cases were divided into 4 groups: Group S: AT<1cm, Group M: 1cm≦AT<2cm, Group L: 2cm≦AT<4cm, Group G: 4cm≦AT. The number of cases for each group was 11, 60, 139 and 44, respectively. Results: The tumors were totally or subtotally removed in all cases in both Group S and Group M. However, in 3% of the cases in Group L and 11% of the cases in Group G the tumors were partially removed for the preservation of hearing. Anatomical preservation of the facial nerve was achieved in 96.8% (243/251) of the patients. As to the facial nerve function, the rate of House-Brackmann Grade 1&2 in Group S was 91% at discharge, 91% at 6 months after the operation and 100% at 1 year after the operation. It was 83%, 96% and 96% in Group M, 61%, 81% and 91% in Group L, 63%, 74% and 78% in Group G, respectively. Thus, the facial nerve function improved with time in cases where the facial nerve were anatomically preserved. Useful hearing was preserved in 90.0% (9/10) of the patients in Group S, 59.0% (23/39) of Group M, and 39.6% (21/53) of Group L. Even in Group G, useful hearing was preserved in 2 out of 3 pts. Over all, the rate of useful hearing preservation was 52.4% (55/105). Conclusion: Both facial nerve function and useful hearing can be preserved well in tumors smaller than 2cm in diameter.

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The aim of vestibular schwannoma surgery for neurosurgeons in the gamma knife era is total tumor removal without any neurological deterioration. We describe anatomical landmarks such as the emissary vein, subarcuate artery, endolymphatic sac, vestibular aqueduct, common crus, jugular bulb, and cochlear aqueduct and the related surgical techniques. The suboccipital approach is one of the most fundamental surgical approaches used in neurosurgery and should always be revised based on recent neuroimaging studies and anatomical knowledge.

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Objectives: To demonstrate the merits and pitfalls of the translabyrinthine approach (TLB) for vestibular schwannomas, in conjunction with evaluation of pre-and post-operative quality of life (QOL) analysis. Case material and methods: During between Nov. 2000 and Feb. 2006, 23 vestibular schwannomas were managed using TLB. Cases included 4 cases with Neurofibromatosis type II and 3 cases with recurrent tumors. The tumors ranged in size from 2 to 6cm (median 3cm). In 3 approaches, the tentorium was divided and a combined petrosal approach was utilized. In 5 cases, preoperative and 3- and 12-month postoperative QOL were evaluated using SF-36 v.2 and EQ5D. Results: Subtotal-total resection was achieved in 21 cases. The facial nerve was anatomically injured in one case and functionally (temporary) in an additional 4 cases (24%). Except for one case with short follow-up, all cases regained facial nerve function of HB grade less than or equal to 2 (95% facial nerve preservation). No neurological complications were experienced; except for one case of postoperative cerebrospinal fluid leakage that required lumbar drainage. Preoperative QOL was low generally compared to the general Japanese population, especially in the sub-domains of vitality, general health perception and bodily pain of SF-36. Postoperatively, the SF-36 and EQ5D scores improved well and approached the general healthy population scores. These trends were different compared to the trends after the retrosigmoid approach, which usually involved delayed recovery of QOL scores. Conclusions: The translabyrinthine approach for vestibular schwannomas requires technical maturation before applying to routine practice. This approach provides a safe and less invasive route in managing technically challenging lesions.

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Since 1976, we have operated on more than 900 acoustic neuromas using the extended middle cranial fossa approach (EMCF). The EMCF ia a combination of the middle cranial fossa approach with a tentorial opening and the posterior petrosal (extended translabyrinthine) approach. This approach includes auditory canal unroofing for intracanalicular tumors, an additional tentorial incision for small sized tumors, and an additional posterior petrosectomy and mastoidectomy for medium and large tumors. The advantages of the EMCF are easy exposure of the intracanalicular tumor and early identification of the facial nerve. Less invasive dissection of the brainstem is accomplished using the EMCF than the suboccipital approach in large tumors. However, contact damage to the facial nerve must be avoided during tumor resection.

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The purpose of this study was to investigate the indication of gamma knife radiosurgery for vestibular schwannomas by analyzing tumor control and possible complications using low marginal doses and conformal multiple shots to fit irregular tumor shapes. The authors evaluated 223 patients with followed-up periods ranging from 5 years to 15 years (mean 7.7 years, median 7.4 years). Marginal doses were 9 to 15 Gy (mean 12.5 Gy median 12 Gy) with corresponding treatment volumes being between 0.1 and 18.7cm^3 (mean 2.6cm^3, median 1.8cm^3). The number of isocenters varied from 2 to 24 shots (mean 9, median 9.2). The actuarial tumor control rates were 95% at 5 years and 94% at 7 years, respectively. Larger tumors (p=0.0068) and those in younger patients (p=0.093) tended to recur significantly. The preservation rates of useful hearing were 84%, 71%, and 64% at 2, 4, and 7 years, respectively. The most deterioration seemed to occur in cases with elderly patients (p=0.0048). Facial and trigeminal functions were preserved at 100%, and 97.8%, respectively. Amongst all patients, 20.6% developed transient dizziness, with persistent dizziness remaining in 1.5% of the total. Fifty-six other patients not in the long-term evaluation consecutively underwent caloric testing and static stabilometry as well as neurological exanimations to evaluate vestibular function in detail, both before and after GKRS. The results showed that 90% of the patients had already developed vestibular dysfunction before the treatment despite reported symptoms of dizziness. GKRS did not significantly affect vestibular function. Hydrocephalus was recognized in 5.5% of all patients, and seemed to occur primarily in cases with larger tumors (p=0.0189). GKRS provides a safe and effective therapy for small to medium sized tumors up to 8cm^3. Long-term hearing preservation rate may be affected by presbycusis in elderly patients.

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We evaluated surgery for thoracic outlet syndrome (TOS) and long-term follow-up outcome. The surgical methods consisted of the transaxillary approach for the first rib resection (FR), the anterior approach for scalenectomy (AAS), and the lateral approach for scalenectomy (LAS). Preoperative symptoms disappeared immediately in 11/14 (79%), 23/26 (88%), and 7/9(78%) of patients in FR, AAS, and LAS, respectively. In long-term follow-up (more than two years), there were three recurrent cases. Two of cases these underwent reoperation (FR) and their symptoms disappeared. We discussed the features and outcomes of these three operative methods.

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Rosai-Dorfman disease (RDD) is a rare idiopathic histioproliferative disease that affects the lymph nodes. Extranodal involvement has been recognized, however central nervous system manifestations are extremely rare. The characteristic radiological features of intracranial RDD are quite similar to those of meningioma, except for the absence of tumor staining on angiography. We report here a rare case of multiple intracranial mass lesions associated with RDD. The radiological features of the case were unilateral multiple intracranial lesions, localized bony thickening of the skull and tumor staining on angiography. To the authors'knowledge, 57 cases of intracranial lesions associated with RDD have been reported previously, of which only 7 cases, including the present case, have demonstrated tumor staining on angiography. Thus, histological examination is essential to correctly diagnose RDD. We also present a review of previously reported intracranial RDD cases and discuss the clinical features and treatment strategies.

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We report three cases of fibrous meningioma with central necrosis. A 42-year-old female with convulsions suffered from cerebral convexity meningioma, a 53-year-old female with left hemiparesis from falx meningioma, and a 68-year-old female with dizziness from cerebellar convexity meningioma were admitted to our hospital with acute onset of symptoms. They underwent gross total removal of the tumors. All cases were diagnosed as fibrous meningioma, with central necrosis without malignant findings. No tumoral recurrence was observed in all cases with a mean follow-up duration of 7.1 years. On the basis of these finding, it is suggested that the sudden occlusion of the main feeding artery caused central necrosis of the meningioma.

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