Management of petrosal veins during microvascular decompression for trigeminal neuralgia

摘要

Objective: Venous compression might be the main cause of incomplete decompression andnsymptom recurrence after microvascular decompression (MVD) in patients with trigeminalnneuralgia. Although it can be killed in most cases, cutting the vein sometimes has the potentialnrisk arising from venous congestion. To maneuver the vein safely, we introduced a temporarynocclusion test of the vein.nMethods: Among 407 consecutive MVD cases, 48 (11.8%) offending and 157 block veins werenencountered. The vein was cut directly in 147 (71.7%). Owing to the potential risk followingnkilling of the vein, 58 (28.3%) patients underwent venous occlusion test with neurophysiologicnmonitoring during the operation. The temporal occlusion should be ceased immediately as soonnas any changes in brainstem auditory evoked potential (BAEP) or trigeminal evoked potentialn(TEP) wave figuration turn up; otherwise, it would last for 15 minutes.nResults: The occlusion test was negative in 53 (91.4%), while positive in five patients (8.6%).nAccording to the results, we cut the vein in test-negative patients, which made the operation easynand offered a satisfactory decompression. Among the five positive cases, the vein was finallynsaved in two and cut in three cases. Yet, all the three patients developed a severe ipsilateralncerebellar edema and brainstem shift after the vein was sacrificed. Despite those patients werenreoperated on immediately for posterior fossa decompression, they remained equilibriumndisorder with numbness in ipsilateral face and mind hemiparesis in contralateral extremitiesnpost-operatively. The residual two patients had an incomplete pain relief.nConclusion: This venous occlusion test could help the surgeon in making a right decision beforenmanipulation of the petrosal veins during MVD. [Neurol Res 2008; 30: 697–700]