[Bone drilling in microvascular decompression for trigeminal neuralgia: high morphological variety of the petrous bone].

Microvascular decompression is now a standard surgical technique for the treatment of trigeminal neuralgia. However, it is occasionally difficult to expose the trigeminal nerves because of the high anatomical variety of vascular or bony structures in the posterior fossa. We reported the case of a 59-year-old woman with trigeminal neuralgia whose site of neurovascular compression could not be observed in microvascular decompression. On approaching the trigeminal nerve, the suprameatal tubercle was so prominent that it prevented adequate visualization of the nerve tract. After drilling out the tubercle concealing the trigeminal nerve behind it, we exposed the nerve entirely and subsequently decompressed it from the superior cerebellar artery. Retrospectively, the suprameatal tubercle was found 3mm high above the posterior surface of the petrous bone. Then, we analyzed the height of suprameatal tubercles in 106 patients who underwent three-dimensional CT of the skull. Mean values of the suprameatal tubercles were 1.4-1.7mm in height, and 5.2% of them were higher than 3mm. The result suggested the high morphological variety of the petrous bone. We emphasize the importance of presurgical evaluation of the petrous bone in trigeminal neuralgia, because the neurovascular compression site may not be exposed sufficiently by the suprameatal tubercle in approximately 5% of the patients.

[Retrospective statistical analysis of clinical factors of recurrence in chronic subdural hematoma: correlation between univariate and multivariate analysis].

OBJECT: Chronic subdural hematoma is common in elderly individuals and surgical procedures are simple. The recurrence rate of chronic subdural hematoma, however, varies from 9.2 to 26.5% after surgery. The authors studied factors of the recurrence using univariate and multivariate analyses in patients with chronic subdural hematoma METHODS: We retrospectively reviewed 239 consecutive cases of chronic subdural hematoma who received burr-hole surgery with irrigation and closed-system drainage. We analyzed the relationships between recurrence of chronic subdural hematoma and factors such as sex, age, laterality, bleeding tendency, other complicated diseases, density on CT, volume of the hematoma, residual air in the hematoma cavity, use of artificial cerebrospinal fluid. RESULTS: Twenty-one patients (8.8%) experienced a recurrence of chronic subdural hematoma. Multiple logistic regression found that the recurrence rate was higher in patients with a large volume of the residual air, and was lower in patients using artificial cerebrospinal fluid. No statistical differences were found in bleeding tendency. CONCLUSION: Techniques to reduce the air in the hematoma cavity are important for good outcome in surgery of chronic subdural hematoma. Also, the use of artificial cerebrospinal fluid reduces recurrence of chronic subdural hematoma. The surgical procedures can be the same for patients with bleeding tendencies.

[Carotid artery stenting via a transbrachial artery: techniques and problems].

Recently, carotid artery stenting (CAS) has been reported to be an alternative of carotid endarterectomy (CEA) for internal carotid artery (ICA) stenosis due to the improvement of protection devices. In general, the transfemoral approach has been chosen for CAS because of the sizes of the devices. However, the transfemoral route seems to be unavailable or at high risk, in cases of severe atherosclerotic changes or aneurysm of the femoral, iliac artery or aorta, or after bypass graft placement. In this report, we presented 5 patients who underwent CAS using the transbrachial approach. The mean stenotic rate of 84% before treatment was reduced to 14% after the procedures. The 30-day morbidity and mortality were both 0%. Major local complications at the puncture site were not encountered. There has been no stroke nor death during a mean follow-up period of 6 months. We suggest that CAS via transbrachial route is an effective and safe treatment for ICA stenosis, by use of low-profile devices and bi-plane DSA equipment, especially in patients who are not eligible for the transfemoral access.

Microvascular decompression of cranial nerves using sheets of a dural substitute--technical note.

Several types of prosthesis are used for microvascular decompression (MVD) surgery for neurovascular compression syndrome. However, most prostheses adhere to the surrounding neuronal structures and occasionally cause granulomas. The present study evaluated a dural substitute made of expanded polytetrafluoroethylene, the Gore-Tex EPTFE patch, as a prosthesis for MVD. Twelve patients with trigeminal neuralgia, 19 patients with hemifacial spasm (HFS), and two patients with glossopharyngeal neuralgia underwent MVD using the dural substitute. In most cases, one or two sheets of the dural substitute were inserted between the offending artery and the compression site covering the cranial nerve and the brainstem. Thirty of the 33 patients experienced complete relief of the symptoms that lasted for at least 10-75 months after the surgery. HFS recurred one month post-surgery in a patient who underwent MVD using two small sheets. Varied grades of hearing disturbance were observed in three patients with HFS. MVD using dural substitute is an easy and efficient method because it is not necessary to move the offending arteries away from the compression site. Large sheets should be positioned over the compression site for sufficient decompression. However, this technique needs to be improved so that the prosthesis does not affect cranial nerve VIII, as three of 19 patients with HFS showed hearing disturbances despite intraoperative monitoring of the auditory brainstem response.