MICROVASCULAR DECOMPRESSION FOR TRIGEMINAL NEURALGIA - A CRITICAL REAPPRAISAL

The results of posterior fossa explorations for trigeminal neuralgia o ver the period 1980-1990 in 58 patients and in 59 procedures were stud ied retrospectively. In 51 procedures vascular compression was treated by microvascular decompression (MVD). In the absence of such a compre ssion, partial sensory rhizotomy (PSR) was performed in 5 cases and on ly adhesiolysis of thickened arachnoidea in 2 cases. In one additional case the procedure was terminated prematurely due to the development of cerebellar edema. Two months postoperatively a good or fair result was obtained in 80% of the procedures. At long-term follow-up (mean 77 .3 months, range 8-146 months), a good or fair result was maintained i n 71%. There was no significant difference in outcome between the MVD group and the other procedures, or between the three groups formed acc ording to the type of vascular compression. However, in the group of 1 0 patients with a history of a procedure affecting the trigeminal gang lion or nerve root the result was worse. In the group of 41 MVD patien ts rendered free of pain at 2 months postoperatively, 8 patients perce ived a recurrence. The annual recurrence rate was calculated to be 2.6 %. There was no mortality in this series but the morbidity rate was 22 % including 1.7% persistent neurological deficit. Compared to the lite rature results of percutaneous controlled differential thermocoagulati on (PCDT), the recurrence and failure rates in the present series appe ar to be more or less the same. As neither of the two is an unequivoca lly more effective treatment, we are of the opinion that the less inva sive procedure should be preferred. Moreover, the possibility that the rmocoagulation might negatively influence the result of a subsequent M VD in case of recurrence underlines the need for a prospective randomi sed trial to clarify this issue.