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Reconstruction of the vein of Labbé by using a short saphenous vein bypass graft

Technical note

Akio Morita and Laligam N. Sekhar

✓ Protection of the vein of Labbé is a significant concern during surgery that involves retraction of the temporal lobe. A cranial base surgical approach, especially one via the presigmoid—petrosal route, carries considerable risk to this venous complex. A case is presented in which a large dominant vein of Labbé was injured during resection of a petroclival meningioma. This vein drained all the sylvian venous circulation as well as the lateral temporal surface; no connection to another venous system was noted. The vein was successfully reconstructed using a short saphenous vein bypass graft. Significant complications could have occurred without this reconstruction. The technique and benefits of this type of reconstruction are discussed.

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Risk of rupture from incidental cerebral aneurysms

Kazuo Tsutsumi, Keisuke Ueki, Akio Morita, and Takaaki Kirino

Object. Controversy still exists about the risk estimation for rupture of untreated saccular aneurysms presenting for causes other than subarachnoid hemorrhage (SAH). The object of this study was to address this issue.

Methods. Between January 1976 and December 1997 in the Aizu Chuou Hospital, 62 patients underwent observation for more than 6 months for saccular, nonthrombotic, noncalcified unruptured aneurysms at locations not related to the cavernous sinus, which were detected in cerebral angiography studies performed for causes other than SAH. Clinical follow-up data in those 62 patients were reviewed to identify the risk of SAH.

All patients were followed until July 1998, with the observation period ranging from 6 months to 17 years (mean 4.3 years). Seven patients (11.3%) developed SAH confirmed on computerized tomography (CT) scanning at a mean interval of 4.8 years, six of whom died and one of whom recovered with a major deficit. In addition, one patient died of the mass effect of the aneurysm, and another after sudden onset of headache and vomiting. The 5- and 10-year cumulative risks of CT-confirmed SAH calculated by the Kaplan—Meier method were 7.5% and 22.1%, respectively, for total cases, 33.5% and 55.9%, respectively, for large (> 10 mm) aneurysms, and 4.5% and 13.9%, respectively, for small (< 10 mm) aneurysms.

Conclusions. Although based on a relatively small, single-institution series, our data indicated that the risk of rupture from incidental, intradural, saccular aneurysms was higher than previously reported, and may support preventive surgical treatment of incidental aneurysms, considering the fatality rate of SAH.

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Symptomatic pituitary metastases

Akio Morita, Fredric B. Meyer, and Edward R. Laws Jr.

Object. The diagnosis and treatment of metastasis to the pituitary gland can be difficult to determine. The goal of this study was to analyze the clinical presentation, treatment, and prognosis of patients who presented with symptomatic pituitary metastasis.

Methods. The cases of 36 patients with symptomatic pituitary metastases were reviewed. The most common primary cancers were breast (33%) and lung (36%). The presenting symptoms included diabetes insipidus, anterior pituitary insufficiency, and retroorbital pain. The overall median length of patient survival following diagnosis of pituitary metastasis was 180 days. In 20 patients (56%), symptoms stemming from pituitary metastasis were the first manifestation of illness. Local control of tumor was associated with significant improvement in survival times (p < 0.05) and amelioration of disabling symptoms including painful ophthalmoplegia and visual field deficits.

Conclusions. Aggressive treatment including both surgical decompression and radiation therapy improves the quality of life in patients suffering from symptomatic pituitary metastasis.

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Editorial. Assessment of the natural history of cerebral aneurysms in the setting of competing risk

Robert M. Starke

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Trigeminal neuralgia caused by a fibrous ring around the nerve

Case report

Toshikazu Kimura, Tetsuro Sameshima, and Akio Morita

Trigeminal neuralgia is usually caused by compression of the nerve by vessels or a tumor. The authors report a case of trigeminal neuralgia not caused by vessel/tumor compression but by a constricting fibrous band around the trigeminal nerve. A 26-year-old man presented with typical trigeminal neuralgia. Although a gradient echo MR imaging demonstrated no offending vessel or a tumor, the patient agreed to undergo exploratory surgery. Intraoperatively, there were no vessels that could be the cause of the neuralgia; instead, the trigeminal nerve was constricted near the root entry zone. After the fiber was cautiously cut, the nerve expanded slightly. The neuralgia resolved without any neurological deficit, and the postoperative course was uneventful. A fibrous band around the trigeminal nerve can cause trigeminal neuralgia. When the symptom is typical and gradient echo MR imaging shows constriction of the trigeminal nerve, surgery is recommended to release the constricted the trigeminal nerve.

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The risk of rupture of unruptured cerebral aneurysms in the Japanese population: a systematic review of the literature from Japan by Morita, et al.

David O. Wiebers

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Radiation-induced spinal cord cavernous malformation

Case report

Masanori Yoshino, Akio Morita, Junji Shibahara, and Takaaki Kirino

P The authors report a case of a 16-year-old girl who presented with progressive gait difficulty 8 years after undergoing spinal radiation therapy for spinal astrocytoma. Magnetic resonance imaging revealed intramedullary multicentric cavity formation in the T4–10 area. Extensive subtotal resection was performed and a pathological examination of the excised tissue demonstrated cavernous malformation with radiation-induced degeneration in the surrounding vessels. This is believed to be the third case of de novo formation of an intramedullary cavernous malformation following spinal radiation therapy.

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Neuroendoscopic aqueductal stent placement procedure for isolated fourth ventricle after ventricular shunt placement

Case report

Masahiro Shin, Akio Morita, Shuichiro Asano, Keisuke Ueki, and Takaaki Kirino

✓ Isolated fourth ventricle (IFV) is a rare complication in patients who undergo shunt placement, and it is not easily corrected by surgical procedures. The authors report a case of IFV that was successfully treated with an aqueductal stent placed under direct visualization by using a neuroendoscope. This 36-year-old suffered meningitis after partial resection of a brainstem pilocytic astrocytoma, and subsequently developed hydrocephalus for which a ventriculoperitoneal shunt was placed. Nine months later, the patient presented with progressive cerebellar ataxia, and magnetic resonance imaging revealed slitlike supratentorial ventricles and a markedly enlarged fourth ventricle, which were compatible with the diagnosis of IFV. The surgical procedure described was performed under visualization through a styletlike slim optic fiberscope inserted into a ventricular catheter. The catheter, with the endoscope inside it, was passed through the foramen of Monro and then through the aqueduct to reach the enlarged fourth ventricle, where membranous occlusion of the foramen of Magendie was clearly visualized. The tip of the catheter was placed in the fastigium of the fourth ventricle. After the procedure, the size of the fourth ventricle was reduced and the patient's symptoms improved. Thus, it is concluded that endoscopic aqueductal stent placement is a simple and safe surgical procedure for treatment of IFV.

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Clip reconstruction of giant vertebral artery aneurysm after failed flow reduction therapy

Toshikazu Kimura, Taichi Kin, Masaaki Shojima, and Akio Morita

Flow reduction therapy is sometimes utilized for difficult aneurysms, but it does not always work. A 42-year-old man presented with headache, dizziness, and slight gait disturbance due to left thrombosed giant vertebral aneurysm. Clip ligation of the VA after the PICA origin was performed for flow reduction based on the CFD analysis. Two months later, the aneurysm showed minor hemorrhage and hydrocephalus, and thrombectomy and clip reconstruction of the VA was performed. He returned to work with slight ipsilateral facial palsy (House & Brackmann grade 2).

The video can be found here: http://youtu.be/-AUVk6nxefQ.

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Prediction of recovery from supplementary motor area syndrome after brain tumor surgery: preoperative diffusion tensor tractography analysis and postoperative neurological clinical course

Kazunori Oda, Fumio Yamaguchi, Hiroyuki Enomoto, Tadashi Higuchi, and Akio Morita

OBJECTIVE

Previous studies have suggested a correlation between interhemispheric sensorimotor networks and recovery from supplementary motor area (SMA) syndrome. In the present study, the authors examined the hypothesis that interhemispheric connectivity of the primary motor cortex in one hemisphere with the contralateral SMA may be important in the recovery from SMA syndrome. Further, they posited that motor cortical fiber connectivity with the SMA is related to the severity of SMA syndrome.

METHODS

Patients referred to the authors’ neurological surgery department were retrospectively analyzed for this study. All patients with tumors involving the unilateral SMA region, without involvement of the primary motor area, and diagnosed with SMA syndrome in the postoperative period were eligible for inclusion. Preoperative diffusion tensor imaging tractography (DTT) was used to examine the number of fiber tracts (NFidx) connecting the contralateral SMA to the ipsilateral primary motor area via the corpus callosum. Complete neurological examination had been performed in all patients in the pre- and postoperative periods. All patients were divided into two groups: those who recovered from SMA syndrome in ≤ 7 days (early recovery group) and those who recovered in ≥ 8 days (late recovery group). Differences between the two groups were assessed using the Student t-test and the chi-square test.

RESULTS

Eleven patients (10 men, 1 woman) were included in the study. All patients showed transient postoperative motor deficits because of SMA syndrome. Tractography data revealed NFidx from the contralateral SMA to the ipsilateral primary motor area via the corpus callosum. The mean tumor volume (early 27.87 vs late 50.91 cm3, p = 0.028) and mean NFidx (early 8923.16 vs late 4726.4, p = 0.002) were significantly different between the two groups. Fisher exact test showed a significant difference in the days of recovery from SMA syndrome between patients with an NFidx > 8000 and those with an NFidx < 8000.

CONCLUSIONS

Diffusion tensor imaging tractography may be useful for predicting the speed of recovery from SMA syndrome. To the authors’ knowledge, this is the first DTT study to identify interhemispheric connectivity of the SMA in patients with brain tumors.