Mamoru Murakami

Correlation between genetic alteration and long-term clinical outcome of patients with oligodendroglial tumors, with identification of a consistent region of deletion on chromosome arm 1p.

In oligodendroglial tumors, allelic losses on chromosome arms 1p and 19q are not only diagnostic molecular markers but also statistically significant predictors of both chemosensitivity and longer recurrence‐free survival. In the current study, the authors attempted to analyze 21 patients genetically and clinically, with special emphasis on the correlation between genetic alterations and long‐term therapeutic results.

A consistent region of deletion on 1p36 in meningiomas: identification and relation to malignant progression.

We analyzed the genetic aberrations on chromosome arms 1p, 10q, and 14q, which are thought to be loci that include putative tumor suppressor genes in meningiomas. We initially conducted molecular genetic testing on a total of 72 tumors including 15 atypical and 8 anaplastic meningiomas using double-target fluorescence in situ hybridization. An incidence of deletion of 1p was observed in 16.3% of histologically benign, 86.7% of atypical, and 87.5% of anaplastic meningiomas. Microsatellite analysis for loss of heterozygosity on 1p, 10q, and 14q was performed in 15 tumors (6 benign, 6 atypical, and 3 anaplastic meningiomas). We detected alimited deleted region on 1p36 in two tumors and suggest a new consistent region of deletion at 1p36.21 approximately p23 distal to D1S507 and proximal to D1S214, which spans 8.21 megabases. In addition, loss of 10q was detected in two of three secondary atypical meningiomas, and loss of 14q in two of three primary anaplastic meningiomas. We suggest that one of the putative suppressor genes is located at 1p36.21 approximately p23, and that 10q loss may contribute to the malignant progression from benign to atypical meningiomas.

Stenting for vertebrobasilar artery stenosis

We report our experience with stenting for symptomatic vertebrobasilar artery stenosis. One hundred and sixteen patients with vertebrobasilar artery stenosis (101 vertebral ostial stenosis, 15 intracranial vertebrobasilar artery stenosis) were treated with stenting. Indication criteria of treatment were 1) symptomatic lesion, 2) angiographical stenosis more than 60%. Under local anesthesia, pre-dilatation was first performed, then stents were placed to the lesion. Successful dilatation was obtained in 115 cases. The stenosis rate reduced to 2% post-stenting in ostial lesions and 16% in intracranial lesions. Transient neurological complications developed in 2 patients. Follow-up angiographies more than 6 months after stenting were performed in 94 patients with ostial lesions and all patients with intracranial lesions. Of these, 8 patients (9.5%) with ostial lesions and 4 patients (27%) with intracranial lesions developed restenosis. All patients with restenosis were treated successfully with PTA (percutaneous transluminal angioplasty). During the follow-up period, 3 patients developed recurrence of VBI (vertebro-basilar insufficiency) symptoms due to restenosis. One patient developed brain stem infarction due to in-stent occlusion 8 months after stenting. Conclusion. Stenting for vertebrobasilar artery stenoses is feasible and safe. Prevention of restenosis, especially in intracranial arteries, is the next problem to be solved.

Stent placement for atherosclerotic stenosis of the vertebral artery ostium: angiographic and clinical outcomes in 117 consecutive patients.

BACKGROUND:Although it is thought to be a safe treatment option, the main concerns related to treating vertebral artery ostium (VAO) stenosis with stents have been the rate of restenosis and the uncertain long-term results. OBJECTIVE:To evaluate the angiographic and clinical results of stent placement for atherosclerotic stenosis of the VAO. METHODS:One hundred seventeen consecutive patients with atherosclerotic VAO stenosis were treated with stent placement over a period of 12 years. All patients were retrospectively analyzed through the use of a prospectively collected database. The indication criteria for this treatment protocol were symptomatic severe VAO stenoses (> 60%) and asymptomatic severe VAO stenoses (> 60%) with incidentally detected infarction in the posterior circulation. The target diameter of stent dilatation from 1997 to 2000 was the normal vessel diameter just distal to the lesion. Moderate overdilation in the proximal portion of the stents has been performed since 2001. RESULTS:Successful dilatation was obtained in 116 of 117 cases. Transient neurological complications developed in 2 patients; however, no patients experienced any permanent neurological complications. One hundred four patients underwent follow-up angiography at 6 months after stenting. The restenosis rate at the 6-month follow-up was 9.6% (10 of 104). Until 2000, the restenosis rate after stenting was 13.3%. Since 2001, the restenosis rate has decreased to 4.5%. The median clinical follow-up period was 48 months. The annual rate of strokes in the posterior circulation was 0.95%. CONCLUSION:Stent placement for atherosclerotic VAO stenosis is considered to be a feasible and safe treatment and may be effective for stroke prevention. The moderate overdilation of stents may be an effective modality for the prevention of restenosis.

Surgical treatment for bilateral carotid arterial stenosis

Carotid endarterectomy (CEA) is a beneficial procedure for patients with high-grade carotid stenosis. However, patients with bilateral carotid stenosis have a higher surgical risk during CEA. Since the introduction of carotid stenting (CAS) may decrease some of the surgical complications of CEA, a combined treatment using CEA and CAS may be favorable for patients with bilateral carotid stenosis. We analyzed the safety and efficacy of this treatment strategy. Eighteen patients with bilateral carotid stenosis were treated from January 2000. Bilateral CEA was performed on the first two patients, CAS then CEA of contra-lateral symptomatic side in 13 patients, and bilateral CAS in three patients. There were no perioperative neurological complications or strokes during the follow-up period (mean 17 months). The combined treatment of CAS and CEA was a safe and effective strategy for bilateral carotid stenosis.

Skull Parosteal Lipoma with Reactive Hyperostosis: A Case Report

A 50-year-old female presented with more than 20-year history of a large subcutaneous mass in the left parieto-occipital portion. Magnetic resonance (MR) imaging revealed the lipomatous mass to show a high signal intensity in both T1- and T2-weighted images. A part of the lipomatous lesion progressed into the underlying hyperostosis and skull. The preoperative diagnosis was skull invasion of a well-differentiated liposarcoma. The tumor was removed completely, including the underlying hyperostosis and skull. Microscopy confirmed a lipoma without any lipoblasts, which was firmly attached to the reactive hyperostosis, and islands of lipoma were involved in the underlying hyperostosis and skull cortex. A pathological diagnosis of parosteal lipoma with reactive hyperostosis was made. Long-term progression of parosteal lipoma may cause to involve the underlying hyperostosis and skull, and led to the diagnosis of invasion of a malignant tumor on MR imaging.

Indication for Surgical Treatment of Carotid Arterial Stenosis in High-Risk Patients

The indication for carotid endarterectomy (CEA) or carotid artery stenting (CAS) has not been established, although the beneficial effects of these surgical treatments for severe cervical carotid stenosis have been confirmed by clinical trial studies. We report our clinical results of CAS and CEA and suggest an appropriate treatment strategy, especially for high-risk patients. From January 2001 to December 2009, we treated 171 carotid lesions by CEA and 251 lesions by CAS. Stenosis was symptomatic in 68%, and the average stenotic rate was 83% in the CEA group. In the CAS group, stenosis was symptomatic in 62%, and the average stenotic rate was 65%. Stenosis was relieved in all cases after CEA or CAS. Surgical mortality with CEA and CAS was 0.6% (1/171) and 0.4% (1/251), respectively. Surgical morbidity by ischemic stroke with CEA and CAS was 2.9% (5/171) and 1.2% (3/251), respectively. Surgical morbidity was not increased in patients with medical risk factors. The long-term outcome after CAS was not inferior to that after CEA. In conclusion, carotid stenosis can be treated with comparably low morbidity and mortality rates using CEA or CAS even in high-risk patients when the method is appropriately selected considering the characteristics of the carotid stenosis.

Ruptured Pseudoaneurysm after Gamma Knife Surgery for Vestibular Schwannoma

Ruptured aneurysms of anterior inferior cerebellar artery (AICA) after radiotherapy for vestibular schwannoma (VS) are rare, and no definite treatment has been established for distal AICA pseudoaneurysms. We describe a 61-year-old man who underwent Gamma Knife surgery (GKS) for left VS. Follow-up magnetic resonance imaging (MRI) revealed partial regression of the tumor. Twelve years after GKS, he suffered from subarachnoid hemorrhage. Initial angiogram showed no vascular lesions; second left vertebral angiogram, 10 days after admission, demonstrated a pseudoaneurysm in the lateral pontine segment of the left AICA. The proximal portion of the AICA was occluded by a coil. Postoperative MRI revealed an infarction on the left side of the pons and brachium pontis. Although the patient suffered from mild postoperative cerebellar ataxia and facial and abducens nerve palsy, he was discharged 1 month postoperatively requiring no assistance with activities of daily living. Twelve months later, he recovered satisfactorily with a modified Rankin Scale grade of 1, and no recanalization of the aneurysm was found on MR angiography. Endovascular parent artery occlusion for ruptured aneurysms at distal AICA carries the risk of brain stem infarction, but should be considered when no other option is available such as after radiotherapy for VS.

Follow-up after undersized dilatation of targeted lesions in carotid artery stenting

Background and purpose. We assessed whether intentional undersized dilatation of targeted lesions during carotid artery stenting (CAS) carried a higher risk of in-stent restenosis (ISR) and correlation to subsequent ischemic stroke in qualifying arteries in the follow-up period. Methods. Consecutive patients undergoing CAS between April 2003 and May 2010 were retrospectively reviewed. The use of a filter device as a distal embolic protection device (EPD) was first approved by Japanese governmental health insurance in April 2008; previously, transient balloon occlusion was used off-label. Until March 2008 (Group A), the target diameter of balloon dilatation was 80–100% of the normal vessel diameter just distal to the stenotic lesion. Moderately undersized dilatation (70–80% of the normal vessel diameter) using the distal EPD was adopted in April 2008 (Group B) in an attempt to reduce the amount of released plaque debris. Results. We analyzed 132 CAS procedures (125 patients) in Group A and 53 CAS procedures (52 patients) in Group B. The mean follow-up period was 35.4 months (35.3 months in Group A and 36.0 months in Group B). Eight lesions (4.3%; 7 in Group A and 1 in Group B) developed ISR. None of the patients had symptomatic ISR, and ISR did not increase in Group B (odds ratio, 0.34; 95% confidence interval, 0.04–2.86; p = 0.32). Conclusions. Undersized dilatation of targeted lesions did not increase the risk of developing ISR, and we suggest it as a viable treatment option to prevent ischemic events during CAS.

Long-term results of carotid endarterectomy and carotid stenting.

INTRODUCTION We report the long-term results of surgery for carotid stenosis in our institute, and suggest a better treatment strategy for high-risk patients. MATERIALS AND METHODS Our series of 352 carotid surgeries conducted between April 1998 and May 2007 were investigated. CEA comprised 134 (38%), whereas CAS comprised 218 (62%). In August 2007, we sent questionnaires to all patients, and analyzed responses up to May 2008. For patients undergoing regular follow-up, the data were gathered from the medical records. The questions were: (1) mRS at that time, (2) the cause of death if the patient was deceased, (3) newly diagnosed stroke, and (4) newly diagnosed coronary heart disease. RESULTS The response rate was 68.8%. The average follow-up period was 31.2 months. The average differences in mRS pre- and postoperation were -0.33 and -0.48 in CEA and CAS, respectively. The mortality rate at >30days was 8.2% in CEA, and 5.0% in CAS. The leading cause of death was heart disease (31.8%). CONCLUSION Our report suggests that CAS is not inferior to CEA, and both procedures can be managed safely if all characteristics of the carotid lesions are considered.