The Effect of Microvascular Decompression in Trigeminal Neuralgia and Hemifacial Spasm

OBJECTIVE: Microvascular decompression(MVD) is an effective technique for the patients who have trigeminal neuralgia(TN) and hemifacial spasm(HS). But, the failed MVD cases have been reported in long term follow-up studies. We introduce our unique operative technique in MVD and analyze the effect of MVD through our modified operative technique, offending vessels in operative field, operative complications, and failed cases. PATIENTS AND METHODS: A series of 52 patients with intractable TN(32 cases) or HS(20 cases) were treated by MVD. Other 7 cases of TN were excluded because they were proved to have TNs secondary to other pathologies, such as nasopharyngeal carcionoma, trigeminal schwannoma, epidermoid tumors, postherpetic neuralgia. The follow-up time was from 3 months to 4 years. RESULT: All 52 patients were treated by retromastoid suboccipital approach. 28 patients of TN were treated with MVD only, and the other 4 patients, were treated with selective sensory root squeezing(1 case), partial sensory rhizotomy(PSR)(2 cases), and PSR with MVD(1 case). Among 20 patients of HS were treated with MVD, 3 patients were not relieved after first operation but were free of spasm after reoperation within 1 week. The degree of nerve root compression was classified as compression and contact and the final outcome compared each other. We used our uniquely designed horseshoe-shaped teflon ring to decompress the vessel from the nerve. In TN, the most common offending vessel was superior cerebellar artery(59.4%) and the final outcomes were as follows: excellent, 87.5%(28 cases): good, 3.1%(1 case): poor, 9.4%(3 cases). In HS, the most common offending vessel was anterior inferior cerebellar artery(55%) and the final outcomes were as follows: excellent, 85%(17 cases): good, 5%(1 case): poor, 10%(2 cases). CONCLUSION: In compressed group, the cure rate was 100%. However, in contact group the cure rate were 81.3% in TN and 75% in HS. RESULT: From the review of the literatures in failed MVD, the etiologies most commonly reported were inadequate decompression, new vessel compression, adhesion and lysis of prosthesis. Our specially designed horseshoe-shaped teflon ring has some advantages to prevent recurrence of symptom by dislodging or slippage of prosthesis or recompression by other vessels. The overall result of our unique MVD was excellent in patients with TN(87.5%) and HS(85%).

Spontaneous Spinal Subarachnoid Hematoma of Unknown Origin: A Case Report

Spontaneous spinal subarachnoid hemorrhage occurs less than 1% of all cases of subarachnoid hemorrhage or hematoma. The causes of spinal subarachnoid hemorrhage or hematoma, include trauma(often caused by lumbar puncture), vascular lesions, neoplastic lesions, coagulopathy, hypertension and Behcet's disease. The occurrence of spontaneous spinal subarachnoid hematoma of unknown pathogenesis is extremely rare. We report a case of spontaneous spinal subarachnoid hematoma of unknown origin at thoracic level of a 33-year-old woman. At admission, she presented with back pain and paraparesis for 3 days prior to admission. There was no history of trauma and use of anticoagulants. On thoracic CT, the lunate shaped high density mass which displaced the spinal cord to right side at T3 to T6 was showed, but did not show contrast enhancement. On thoracic MRI, this mass was iso-signal intensity in T1 weighted image and low-signal intensity in T2 weighted image. In GDTA-enhanced MRI, the mass was not enhanced. We removed subarachnoid hematoma with total laminectomy through T4 to T6. Her neurologic deficit was fully improved and discharged. We conclude that even if the rate of spontaneous spinal subarachnoid hematoma of unknown is low, the clinical symptom may progress rapidly. Therefore, early diagnosis and removal of hematoma is essential for improvement of the patient's neurologic deficit. inhibition of vestibular nuclear complex through nhibitory Purkinje system.