Background: The neurovascular conflict in trigeminal neuralgia is an intractable condition; medical treatment is usually of long duration and can be annoying for both patients and clinicians. Aim: This prospective study was designed to assess the outcome of microvascular decompression (MVD) in patients with more than 3 years' history of intractable idiopathic trigeminal neuralgia (TN) and poor response to drugs. Materials and Methods: Twenty-one patients (8 females and 13 males) with intractable idiopathic TN (group 1) underwent MVD and were followed up for 2 years. Group 2 (n = 15), which included 6 females and 9 males, received pharmacotherapy. The outcome responses of pain relief were evaluated using a 10-cm visual analog scale (VAS) and the Barrow Neurological Institute (BNI) scoring system. The patients' morbidity was recorded as well. Results: All patients fulfilling the inclusion criteria were offered MVD surgery. Freedom from pain was achieved immediately after surgery in 95.2% (n = 20) of patients in group 1, and 90.5% (n = 19) had sustained relief over the follow-up period. There were no statistical significance recurrences or surgical complications in group 1 (P>0.5), while 53.3% (n = 8) of the subjects in group 2 showed poor response with pharmacotherapy over the same period of time and many patients experienced drug intolerance that had statistical significance (P<0.01). Conclusion: Early MVD in TN can help patients avoid the side effects of drugs and the adverse psychological effects of long-term pharmacotherapy and prolonged morbidity.

Nakamura, Makoto M.D.; Struck, Melena Cand. Med.; Roser, Florian M.D.; Vorkapic, Peter M.D., Ph.D.; Samii, Madjid M.D., Ph.D.

Object The aim of this study was to describe the symptomatology, radiological features, and surgical treatment of patients with cavernous angiomas within the internal auditory canal (IAC). Methods The authors reviewed the cases of seven patients with cavernous angiomas in the IAC that had been surgically treated in the 22-year period between 1983 and 2005. All the patients had presented with sensorineural hearing loss, and four suffered from tinnitus. Four patients also reported facial symptoms such as hemispasm or progressive palsy; one of these patients had presented with sudden facial paresis due to intrameatal tumor hemorrhage. According to computed tomography (CT) results, the lesions caused enlargement of the IAC. Interestingly, these same angiomas showed variable features on magnetic resonance (MR) imaging, making their differentiation from intrameatal vestibular schwannomas (VSs) sometimes impossible. In all patients the lesions were totally removed via the suboccipital retrosigmoid approach. They could be dissected away from the facial nerve in five cases, whereas in two cases, because of the location of the lesion, the seventh cranial nerve had to be sectioned and repaired with a sural nerve graft. Transient worsening of seventh cranial nerve symptoms occurred in two patients, with postoperative improvement in each of them. The cochlear nerve could not be functionally preserved because of its extreme adherence to the tumor, although its continuity was preserved in four patients. Complete deafness was the only postoperative complication. Conclusions Cavernous angiomas of the IAC are very uncommon lesions that can imitate the symptoms of VSs. Although it is the most sensitive study available, MR imaging does not show sufficiently specific findings to differentiate the two lesion types. Thus, the preoperative diagnosis must be based on patient symptoms plus the CT and MR imaging features.

OBJECTIVE Tuberculum sellae meningiomas present a special challenge because of their proximity to arteries of the anterior circulation, anterior visual pathways, and the hypothalamus. The authors report on the clinical outcome after surgical treatment of tuberculum sellae meningiomas in our neurosurgical department. METHODS A retrospective study was conducted analyzing the charts of the patients, including surgical records, discharge letters, histological records, follow-up records, and imaging studies. Patients with associated neurofibromatosis Type 2 were excluded from the study. RESULTS One thousand eight hundred meningiomas were operated on between 1978 and 2002. Seventy-two of these patients had tuberculum sellae meningiomas; four had undergone previous surgical procedures in outside hospitals. Fifty-five patients were women; 17 were men. Their mean age was 54.3 years (range, 30–86 yr). All patients had visual disturbances at presentation. Tumors were operated through the bifrontal approach (n = 21, from 1978 through 1995), the pterional/frontotemporal approach (n = 21, from 1982 through 2002), and the frontolateral approach (n = 30, from 1984 through 2002). Total tumor removal was achieved in most patients (Simpson 1 + 2, 91.7%). The perioperative mortality rate was 2.8% (two out of 72 patients). Immediate postoperative improvement of visual disturbance was observed in 65% of patients. Visual improvement was dependent on the duration of preoperative visual symptoms, but not on preoperative visual acuity or tumor size. The visual improvement rate was significantly better in patients who underwent frontolateral tumor resection (77.8%) compared with those who underwent bifrontal craniotomy (46.2%). The overall recurrence rate was 2.8% (two out of 72 patients). The mean follow-up time for all patients was 4 to 238 months (mean, 45.3 mo [3.8 yr]). CONCLUSION From 1978 through 2002, tuberculum sellae meningiomas were removed microsurgically using three different surgical approaches. Considering the operative morbidity and mortality, the frontolateral and pterional approach provided remarkable improvement compared with the bifrontal approach. These approaches allowed quick access to the tumor and were minimally invasive with less brain exposure, but still engendered high rates of total tumor removal. By comparison, the frontolateral approach provided the best results concerning visual outcome while representing the least invasive surgical approach.

BACKGROUND:The aim of this study is to assess the morbidity and mortality of meningioma surgery in patients over 70 years of age harbouring a tumour at the cerebellopontine angle as one representative location of the posterior fossa in comparison with a matched group of young patients.METHOD:A retrospective analysis based on clinical charts, surgical records, histological records, imaging studies and follow up records was conducted to select patients over 70 years who underwent surgery for cerebellopontine angle meningiomas. Tumours with comparable size and location were matched with the younger group.FINDINGS:There were 421 meningiomas located in the cerebellopontine angle, 21 patients were older than 70 years (range 70-84). Median Karnofsky-Index at presentation was 80 (50-90), 16 patients had a physical status grading ASA 2 and 5 patients ASA 3. The average length of hospital stay was 22 days (7-99 days). The postoperative median Karnofsky score at time of discharge was 80 (50-90). The most common medical complication was postoperative pneumonia in 4 patients, among them 3 patients had lower cranial nerve disturbances postoperatively. There were 56 younger patients (mean age 52.4 years; range 24.5-69.75 years) with corresponding tumour size and location. Pre-op Karnofsky score was 80 (70-90), 53 patients were graded as ASA 2 and 3 patients as ASA 3. Length of hospital stay was 13.6 days (8-32 days). Post-op Karnofsky score was 80 (50-90). Among 5 patients with postoperative lower cranial nerve disturbances no patient had pneumonia postoperatively. There was no peri-operative mortality in either group.CONCLUSIONS:With modern neurosurgical techniques and neuro-anesthesia elderly patients with CPA meningiomas can be operated on with acceptable low morbidity and good neurological outcome but recovery from surgery lasts longer compared to younger patients. However, postoperative lower cranial nerve deficits in elderly patients may not be well tolerated compared with younger patients.

OBJECT:Only some meningiomas of the cerebellopontine angle (CPA) extend into the internal auditory canal (IAC) or arise from its dural lining. The authors investigated cases of CPA tumors in which the meningioma was inserted in the dura mater in or at the ICA or infiltrated a cranial nerve.METHODS:The authors reviewed patient charts including surgical and clinical records, intraoperative recordings of auditory evoked potentials, records of postoperative auditory examinations, and imaging studies. In a series of 421 patients harboring CPA meningiomas, 72 patients in whom there was dural involvement of the IAC were investigated. Total tumor resection was achieved in 86.1%. In 34 patients, opening of the IAC was required for total tumor removal; this procedure did not influence the patient functional outcome. Among patients with secondary involvement of the IAC, anatomical preservation of the facial and cochlear nerves was obtained in 94%, whereas among patients in whom the lesion arose from the dura in or at the IAC these values were 80 and 75%, respectively. Functional preservation of the seventh and eighth cranial nerves in cases of tumor extension within the IAC was 86 and 77%, respectively, whereas in cases in which the IAC was involved it was only 60%. In four of five patients in whom the tumor had its origin in the dura mater within the IAC, the seventh or eighth cranial nerve had to be sacrificed to achieve tumor removal because of the lesion's infiltrative behavior. Facial nerve reconstruction by sural grafting was performed in the same operative procedure.CONCLUSIONS:Meningiomas of the CPA involving the IAC require special surgical management. Dural involvement of the IAC requires opening by using a diamond drill, a procedure that does not influence cranial nerve outcome. The increased rate of cranial nerve morbidity is attributed to the infiltrative behavior of these meningiomas. If affected nerve segments have to be sacrificed, immediate reconstruction enables satisfactory long-term results.

BACKGROUND:Sphenoid wing meningiomas (SWMs) with osseous involvement are neurosurgically challenging because of their position within the skull base and their high rates of recurrence. Sufficient resection of these meningiomas requires extensive surgical exposure. We report on 82 patients with meningiomas infiltrating the sphenoid wing, analyzing radiological appearance and its influence on surgical management. METHODS:Charts of the patients including surgical records, clinical reports, histological examinations, imaging studies, and meticulously focusing questionnaires were reviewed. RESULTS:Among the 82 patients with osseous-involved SWMs, the mean age was 52.2 years in the female group and 54.7 years in the male group with a mean follow-up of 66.23 months (24-206). Histological evaluation revealed World Health Organization grade I meningiomas in 94% of case patients, tumor infiltration of examined bone in all case patients, and proliferation rates of 2.2% Ki-67. Magnetic resonance imaging appearance of the SWMs demonstrated various densities as well as Gd enhancement within the affected bone. Recurrence rates in this subgroup of SWMs are higher (>30%) compared with meningiomas without osseous involvement (11.6%). CONCLUSION:Osseous involvement in SWMs accounts for lower resection and higher recurrence rates than meningiomas in other locations. In those cases with involvement of the cavernous sinus, a subtotal but extensive removal combined with bony decompression of the cranial nerves at the superior orbital fissure and optic canal frequently produces good functional and cosmetic results.

OBJECTIVE: Meningiomas of the cerebellopontine angle (CPA) share a common location, but their site of dural origin and their relationship to surrounding neurovascular structures of the CPA are variable. The clinical presentation and outcome after surgical resection are different because of the diversity of this tumor entity. We report on a series of 421 patients with CPA meningiomas, with special emphasis on the analysis of the preoperative and postoperative facial and cochlear nerve function in relation to the site of dural attachment and main tumor location in the CPA cistern.METHODS: Among 421 patients, the charts of 347 patients with complete clinical data, including the history and audiograms, imaging studies, surgical records, discharge letters, histological records, and follow-up records, were reviewed retrospectively. Data about preoperative and postoperative facial nerve function were available in 334 patients, and audiometric analysis was conducted in 333 patients. Patients with neurofibromatosis Type 2 were excluded from the study.RESULTS: There were 270 women and 77 men, with a mean age of 53.4 years (range, 17.6-84 yr). Among these patients, 32.9% of the tumors originated at the petrous ridge anterior to the inner auditory canal (IAC) (Group 1), 22.2% showed involvement of the IAC (Group 2), 20.2% were located superior to the IAC (Group 3), 11.8% were inferior to the IAC (Group 4), and 12.9% were posterior to the IAC, originating between the IAC and the sigmoid sinus (Group 5). Patients presented with disturbance of Cranial Nerves V-VIII, the lower cranial nerves, and ataxia, depending on the main tumor location. Tumor resection was performed through a suboccipital-retrosigmoidal approach in the semisitting position in 95% of the patients. A combined supratentorial-infratentorial presigmoidal approach was performed in 5%. Total tumor removal (Simpson Grade I and 2) was achieved in 85.9% and subtotal removal in 14.1%. The best initial postoperative facial and auditory nerve function was observed in tumors belonging to Groups 3 and 5. Recovery from preoperative deafness was observed in 1.8% of patients. On long-term follow-up, good facial nerve function (House-Brackmann Grade 1 or 2) was observed in 88.9% of patients. Hearing preservation among patients with preoperative functional hearing was documented in 90.8% on long-term follow-up.CONCLUSION: Although the outcome of facial and cochlear nerve function is different in CPA meningiomas, depending on the topographic classification of these tumors, preservation of the cochlear nerve is possible in every tumor group and should be attempted in every patient with CPA meningioma. it has to be kept in mind that recovery of hearing was also observed in patients with preoperative profound hearing deficits.

Introduction: Meningiomas of CPA involving the IAC represent a particular clinical and surgical entity due to their critical relationship to neurovascular structures. The extent of resection of these tumors depends on their tumor biology (displacement or infiltration) and on their dural origin. Only some of those tumors extend into the IAC (anterior to or encasing the nerves) or arise from its dural lining. We investigated the clinical outcome of the cranial nerves VII and VIII in cases of dural insertion in the IAC or plain extension into the IAC.

The authors describe the first case of an intracranial transition of a melanocytoma into a primary malignant melanoma within a short time. A 37-year-old woman presented with progressive brainstem syndrome due to a tumor, originally diagnosed and treated 12 years earlier, that extended from the petroclival area to the anterior craniocervical junction. The histological workup following subtotal tumor resection of the initial tumor had revealed the typical features of a fibrous melanocytic meningioma without increased proliferation. Ten years after the patient had completed treatment for the melanocytic meningioma, control neuroimaging demonstrated growth of the residual tumor with compression of the brainstem. Another neurosurgical intervention revealed a dark tumor of hard consistency. At this time immunohistochemical examinations demonstrated melanocytic features (expression of vimentin, S100 protein, and melan A) of the lesion with focally increased proliferation (5% of Ki-67-positive cells) but no higher mitotic activity. Clinical signs of deterioration along with imaging-confirmed tumor progression precipitated another operation within 7 months. A neuropathological examination revealed epithelial and anaplastic changes and indicated that the MIB-1 indices were greater than 25%. Pleomorphic changes and a focal high mitotic activity led to the diagnosis of a primary cerebral malignant melanoma. The patient's later clinical course consisted of a rapid diffuse meningeal spread of the lesion throughout the entire brain and spine. Despite whole-brain and stereotactic radiation therapy as well as chemotherapy, the patient died 4 months after the last neuropathological diagnosis. Although grossly resembling a meningioma, melanocytomas lack the former's histological and immunohistochemical features. The biological behavior of a melanocytoma is variable and recurrence may happen after subtotal resection, but intracranial transition into a malignant melanoma has not been observed previously.

Long-term follow-up reports on chondroid lesions of the skull base are rarely presented in the literature. There are virtually no data on natural growth rates of these tumors based on MRI obtained over a period of 10 years or longer. We followed a patient who has had such a lesion for more than 12 years. A non-progressive, slight abducens palsy has been the only associated symptom so far. Even though the patient was operated on for an additional intracranial arterio-venous malformation, clinical features and chromosomal testing excluded Maffucci's syndrome. The MRI follow-up in this case provides an extraordinary perspective on the natural history of chondroid skull base tumors.

With only four histologically proven cases in the literature, solitary skull base metastasis of thyroid carcinoma is extremely rare. Having treated another patient harboring a lesion with osseous destruction in the petroclival region and downward soft tissue extension we analyzed this case in conjunction with previous reports. In contrast to parenchymal brain metastasis that usually consists of the papillary type, histological examination revealed differentiated follicular tumors in all cases. All were located around the clivus. The radiographic picture resembled that of chordomas or chondrosarcomas. In the tissue obtained during thyroidectomy no evidence of primary malignancy was found in any of the cases according to standard histological criteria. In our case, a recently developed immunocytological marker - galectin-3 - was applied to differentiate between ectopic thyroid adenoma and carcinoma. The results were indicative of anaplastic growth. Tumor remnants responded well to postoperative 131I internal radiation and TSH suppression therapy. Distant metastasis of follicular thyroid carcinoma has to be considered in the differential diagnosis of destructive skull base lesions. Histological evaluation should include immunohistochemistry or clonal analysis to differentiate between adenomatous and carcinomatous growth and initiate effective radiotherapy early. Prognosis is by far not as poor as in brain metastases and appears to depend largely on location, size and histological appearance.

Intracranial fibromuscular dysplasia (FMD) is a vascular disease of unknown origin occurring predominantly in young women. The internal carotid artery is most often involved, but other cerebral arteries may also be affected. We report the case of a young woman presenting with an unusual angiographic appearance of intracranial FMD of the internal carotid artery (ICA) that could not be categorized into any type of the Osborn-Anderson classification. During follow up the patient presented with an intracerebral and subarachnoid hemorrhage. Repeated angiography revealed multiple aneurysms in the pathologic segment of the vessel. The patient underwent surgical treatment with clipping of the aneurysms, wrapping of the pathologic segment of the ICA and biopsy of the superficial temporal artery. Histopathological sections revealed FMD of the intimal type. alpha(1)-antitrypsin blood levels were normal. Cases of intracranial FMD previously reported in the literature are reviewed and various aspects of this rare disease are discussed.

The purpose of this study was to investigate experimentally, factors determining the navigation accuracy of the MKM navigation system by Zeiss. The MKM consists of an operating microscope mounted to a six-axis motor-driven robot arm and an alpha-workstation. The image-guided surgery device provides navigation information based on calculation of the cartesian coordinates of the robot arm, and coordinates of the focus point assessed by laser assisted measurement. Navigation information (current position, direction and distance to a previously selected target) is optically projected into the microscopic field. Following factors were examined in an experimental setting for their impact on accuracy of the MKM: optical system, mechanical precision of the robot arm, and registration procedure. The robot arm and the optical system of the microscope allow high precision measurements of any focus point (error < 2 mm if the following aspects are considered: the use of auto-focus function instead of manual focusing, positioning of the registration points as a square or a triangle focus point should be selected on a surface that is perpendicular to the optical axis.

Introduction. A cadaveric study was undertaken to investigate the usefulness and reliability of a microscope based navigation system (NS) for skull base surgery.

We report the case of a 44-year-old patient with a MRI scan showing a newly developed cavernoma after two highly calcified lesions had been excised surgically. Six other cavernous malformations had been followed by MR imaging over a 2-year period. The coexistence of the two extremes of cavernous malformations in terms of lesions development--de novo and ossified lesions has not been reported previously and has implications for both the follow-up and the natural history of these malformations. The potential for developing new cavernous malformations persists and does not seem to be related to the evolutional stage of pre-existing lesions. It is suggested that these patients need to be followed up by MRI on a regular basis.