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Shinichiro Miyazaki, Takanori Fukushima and Takamitsu Fujimaki

✓ Two patients with large high-cervical paragangliomas were treated with radical resection and placement of a cervical-to-petrous internal carotid artery saphenous vein bypass. The high-cervical and infratemporal segments of the internal carotid artery engulfed within the tumor were resected and successfully replaced with a saphenous vein interposition graft. The postoperative course was uneventful in both cases and follow-up angiography revealed satisfactory reconstruction of the high-cervical and infratemporal skull base carotid artery. The operative technique, indications, and potential future applications of this newly developed skull base bypass procedure are discussed.

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Takamitsu Fujimaki, Takanori Fukushima and Shinichiro Miyazaki

✓ The results in 122 patients with trigeminal neuralgia who underwent percutaneous retrogasserian glycerol injection are presented. Eighty patients were followed from 38 to 54 months. The recurrence rate at 54 months was 72% (Kaplan-Meier analysis), and the median pain-free interval was 32 months. Complications associated with the procedure were significantly high: 63% of the patients had definite hypesthesia of the face and 29% had unpleasant dysesthesias, including two cases of anesthesia dolorosa. Sensory disturbances were most frequent in patients who had received a previous alcohol block procedure. Among the patients without previous peripheral procedures, 50% developed sensory disturbances. Because of the high rates of recurrence and sensory disturbances, the authors prefer microvascular decompression for the management of trigeminal neuralgia.

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Han Soo Chang, Takanori Fukushima, Shinichiro Miyazaki and Teruaki Tamagawa

✓ A case of a ruptured fusiform aneurysm of the posterior cerebral artery is reported. The aneurysm was excised and end-to-end anastomosis was carried out between the two ends of the posterior cerebral artery. There is no previous report of a posterior cerebral artery aneurysm treated with this technique. The pertinent literature is reviewed and the significance of this technique in the treatment of unclippable cerebral aneurysms is discussed.

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Akio Morita, Takanori Fukushima, Shinichiro Miyazaki, Tsuneo Shimizu and Masayuki Atsuchi

✓ Primitive trigeminal artery (PTA) is an extremely rare cause of tic douloureux. None of the reports on PTA variant, which is an anomalous cerebellar artery arising from the internal carotid artery without anastomosis to the basilar artery, has suggested the possibility of this vessel causing tic douloureux. Eight cases of tic douloureux are reported in which a PTA or PTA variant was found during microvascular decompression (MVD). These cases were derived from a series of 1257 patients treated with MVD for tic douloureux. In one patient, the neuralgia was caused by a combination of vessels: a PTA, the superior cerebellar artery, and the anterior inferior cerebellar artery. In the other seven cases, a PTA variant was compressing the root entry zone of the trigeminal nerve. All eight patients gained excellent pain relief after MVD of the root entry zone. The significance of PTA's and PTA variants as the cause of tic douloureux and the effectiveness of MVD in the management of such cases are discussed.

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Shin-ichi Tsubaki, Takanori Fukushima, Teruaki Tamagawa, Shin-ichiro Miyazaki, Kazuo Watanabe, Nobumasa Kuwana and Tsuneo Shimizu

✓ Posterior fossa microvascular decompression surgery was attempted in 1257 patients with trigeminal neuralgia (TN), of whom seven had a very unusual cryptic angioma. The lesions were not visualized on preoperative enhanced computerized tomography scans, and serial angiography demonstrated a small vascular stain in only one case. The character of the facial pain was indistinguishable from TN caused by vascular compression and there was no other specific symptomatology. The patients' age and sex distributions were also compatible with classical TN. Cryptic angiomas presenting as typical TN without other symptoms have not been reported before, but they should be kept in mind in the differential diagnosis and surgical management of TN.

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Nakao Ota, Rokuya Tanikawa, Hirotake Eda, Takashi Matsumoto, Takanori Miyazaki, Hidetoshi Matsukawa, Takeshi Yanagisawa, Go Suzuki, Shiro Miyata, Jumpei Oda, Kosumo Noda, Toshiyuki Tsuboi, Rihei Takeda, Hiroyasu Kamiyama and Sadahisa Tokuda

OBJECTIVE

Bilateral vertebral artery dissecting aneurysms (VADAs) have a poor prognosis because progressive enlargement of the aneurysms compresses the brainstem or causes subarachnoid hemorrhage. The trapping of 1 vertebral artery (VA) places increased hemodynamic stress on the contralateral VA and may lead to enlargement and rupture. Therefore, management strategies are controversial. This study describes a radical treatment for bilateral VADAs using bypass surgery.

METHODS

Seven patients with bilateral VADAs were included. Three patients were treated by trapping of 1 VA via coiling or clipping at another hospital; the previously treated VA in 1 patient and the contralateral untreated VA in 2 patients subsequently enlarged. The other 4 patients presented without previous intervention and progressive enlargement of the aneurysms.

RESULTS

The post–coil embolization patients underwent V3–posterior cerebral artery (PCA) bypass and trapping. The other 4 patients underwent VA reconstruction via V3–V4 or V4–V4 bypass, with contralateral trapping on a separate day in 3 patients and observation in 1 patient. Perioperative complications included 1 case of cerebrospinal fluid leakage for which the patient required an additional operation, 1 case of dysphagia and facial palsy due to sigmoid sinus thrombosis, and 1 case of dysphagia. The long-term outcomes of these patients were favorable.

CONCLUSIONS

Patients with bilateral VADAs require treatment on both sides. If VA trapping is performed first, the treatment options for the other side are limited to V3-PCA bypass and trapping. This procedure is effective; however, it is also invasive and technically difficult. In cases of bilateral VADAs in which it is feasible to reconstruct 1 side, the best approach is to begin by reconstructing the VA that appears technically easiest, followed by trapping of the contralateral VADA. This strategy allows enough time to suture vessels because contralateral reverse flow is maintained.

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Hidetoshi Matsukawa, Hiroyasu Kamiyama, Toshiyuki Tsuboi, Kosumo Noda, Nakao Ota, Shiro Miyata, Takanori Miyazaki, Yu Kinoshita, Norihiro Saito, Osamu Takahashi, Rihee Takeda, Sadahisa Tokuda and Rokuya Tanikawa

OBJECTIVE

Only a few previous studies have investigated subarachnoid hemorrhage (SAH) after surgical treatment in patients with unruptured intracranial aneurysms (UIAs). Given the improvement in long-term outcomes of embolization, more extensive data are needed concerning the true rupture rates after microsurgery in order to provide reliable information for treatment decisions. The purpose of this study was to investigate the incidence of and risk factors for postoperative SAH in patients with surgically treated UIAs.

METHODS

Data from 702 consecutive patients harboring 852 surgically treated UIAs were evaluated. Surgical treatments included neck clipping (complete or incomplete), coating/wrapping, trapping, proximal occlusion, and bypass surgery. Clippable UIAs were defined as UIAs treated by complete neck clipping. The annual incidence of postoperative SAH and risk factors for SAH were studied using Kaplan-Meier survival analysis and Cox proportional hazards regression models.

RESULTS

The patients’ median age was 64 years (interquartile range [IQR] 56–71 years). Of 852 UIAs, 767 were clippable and 85 were not. The mean duration of follow-up was 731 days (SD 380 days). During 1708 aneurysm years, there were 4 episodes of SAH, giving an overall average annual incidence rate of 0.23% (95% CI 0.12%–0.59%) and an average annual incidence rate of 0.065% (95% CI 0.0017%–0.37%) for clippable UIAs (1 episode of SAH, 1552 aneurysm-years). Basilar artery location (adjusted hazard ratio [HR] 23, 95% CI 2.0–255, p = 0.0012) and unclippable UIA status (adjusted HR 15, 95% CI 1.1–215, p = 0.046) were significantly related to postoperative SAH. An excellent outcome (modified Rankin Scale score of 0 or 1) was achieved in 816 (95.7%) of 852 cases overall and in 748 (98%) of 767 clippable UIAs at 12 months.

CONCLUSIONS

In this large case series, microsurgical treatment of UIAs was found to be safe and effective. Aneurysm location and unclippable morphologies were related to postoperative SAH in patients with surgically treated UIAs.

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Kentaro Mori, Takuji Yamamoto, Masahiro Miyazaki, Yasukazu Hara, Yasuhisa Aiko, Nobuhiro Koike, Shinsuke Sakamoto, Yasuaki Nakao and Takanori Esaki

Object

The optimal CSF Mg++ concentration for vasodilation of spastic cerebral arteries after subarachnoid hemorrhage (SAH) and its duration are unknown. The temporal profile of the vasodilatory effect and optimal CSF Mg++ concentration after the intracisternal injection of MgSO4 solution were investigated in an SAH model in canines.

Methods

Cerebral vasospasm was induced by experimental SAH using a 2-hemorrhage model in 26 female beagles. On Day 7, 0.5 ml/kg of 15, 10, 5, or 0 mmol/L MgSO4 in Ringer solution was injected into the cerebellomedullary cistern. Angiography was performed on Day 1 (before SAH) and before and 1, 3, and 6 hours after the intracisternal injection on Day 7 to measure arterial diameters of the basilar artery (BA), superior cerebellar artery (SCA), and vertebral artery (VA). Cerebrospinal fluid Mg++ was also measured at the same time.

Results

Arterial diameters of the BA, SCA, and VA were significantly decreased by vasospasm on Day 7. Arterial diameter ratios (ratio of arterial diameter after MgSO4 injection to diameter before injection on Day 7) of the BA and SCA at 1 and 3 hours after and the VA at 1 hour after intracisternal injection of the MgSO4 solution were positively correlated with the CSF Mg++ concentration. All arterial diameter ratios, except 1 point of the SCA, exceeded 1 if the CSF Mg++ concentration was > 3 mEq/L at 1 hour after injection. Animals with CSF Mg++ concentrations > 3 mEq/L at 1 hour after injection (11 dogs) showed significantly increased arterial diameters of the BA at 1 and 3 hours after and of the SCA and VA at 1, 3, and 6 hours after injection, as compared with the diameters before injection. The CSF Mg++ concentration significantly increased at 1 hour (3.73 ± 0.69 mEq/L, p < 0.01) and 3 hours (2.05 ± 0.35 mEq/L, p < 0.01) after the intracisternal injection as compared with the baseline value (1.41 ± 0.20 mEq/L).

Conclusions

The reversible effect of an intracisternal injection of MgSO4 solution on the spastic artery requires CSF Mg++ concentrations > 3 mEq/L. The vasodilatory effect continues for 3–6 hours after injection. These results suggest that the continuous infusion or intermittent intracisternal injection of MgSO4 is needed to maintain the optimal CSF Mg++ concentration and constantly ameliorate cerebral vasospasm.

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Hidetoshi Matsukawa, Hiroyasu Kamiyama, Takanori Miyazaki, Yu Kinoshita, Nakao Ota, Kosumo Noda, Takaharu Shonai, Osamu Takahashi, Sadahisa Tokuda and Rokuya Tanikawa

OBJECTIVE

Perforator territory infarction (PTI) is still a major problem needing to be solved to achieve good outcomes in aneurysm surgery. However, details and risk factors of PTI diagnosed on postoperative MRI remain unknown. The authors aimed to investigate the details of PTI on postoperative diffusion-weighted imaging (DWI) in patients with surgically treated unruptured intracranial saccular aneurysms (UISAs).

METHODS

The data of 848 patients with 1047 UISAs were retrospectively evaluated. PTI was diagnosed on DWI, which was performed the day after aneurysm surgery. Clinical and radiological characteristics were compared between UISAs with and without PTI. Poor outcome was defined as an increase in 1 or more modified Rankin Scale scores at 12 months after aneurysm surgery.

RESULTS

Postoperative DWI was performed in all cases, and it revealed PTI in 56 UISA cases (5.3%). Forty-three PTIs occurred without direct injury and occlusion of perforators (43 of 56, 77%). Poor outcome was more frequently observed in the PTI group (17 of 56, 30%) than the non-PTI group (57 of 1047, 5.4%) (p < 0.0001). Thalamotuberal arteries (p < 0.01), lateral striate arteries (p < 0.01), Heubner’s artery (p < 0.01), anterior median commissural artery (p < 0.05), terminal internal carotid artery perforators (p < 0 0.01), and basilar artery perforator (p < 0 0.01) infarctions were related to poor outcome by adjusted residual analysis. On multivariate analysis, statin use (OR 10, 95% CI, 3.3–31; p < 0.0001), specific aneurysm locations (posterior communicating artery [OR 4.1, 95% CI 2.1–8.1; p < 0.0001] and basilar artery [OR 3.1, 95% CI 1.1–8.9; p = 0.031]), larger aneurysm size (OR 1.1, 95% CI 1.1–1.2; p = 0.043), and permanent decrease of motor evoked potential (OR 38, 95% CI 3.1–468; p = 0.0045) were related to PTI.

CONCLUSIONS

Despite efforts to avoid PTI, it occurred even without direct injury, occlusion of perforators, or evoked potential abnormality. Therefore, surgical treatment of UISAs, especially with the aforementioned risk factors of PTI, should be more carefully considered. The evaluation of PTI in the territory of the above-mentioned perforators could be useful in helping predict the clinical course in patients after aneurysm surgery.