PARTIAL SENSORY TRIGEMINAL RHIZOTOMY AT THE PONS FOR TRIGEMINAL NEURALGIA

Microvascular decompression is preferred among open procedures for the treatment of trigeminal neuralgia. However, in some cases the decompr ession cannot be performed, either because no significant vascular com pression of the trigeminal nerve is found at surgery or because a pati ent's vascular anatomy makes it unsafe. Partial sensory rhizotomy is a commonly used alternative in these instances. The outcome after parti al sensory rhizotomy was reviewed retrospectively in 83 patients with an average follow-up period of 72 months. Sixty-four (77%) of these pa tients had no evidence of vascular contact at operation. The remaining 19 patients (23%) had vascular structures in proximity to the trigemi nal nerve but still underwent partial sensory rhizotomy in place of or in addition to microvascular decompression either because the offendi ng vessel could not be moved adequately (11 cases) or because the vasc ular contact was considered insignificant (eight cases). Outcome was c lassified as: excellent if there was no trigeminal neuralgia postopera tively; good if pain persisted or recurred but was less severe than pr eoperatively; and poor if persistent or recurrent pain was equal to or greater than the preoperative pain in severity and was refractory to medication, or was severe enough to require additional surgery. The ou tcome was excellent in 40 patients (48%), good in 18 (22%), and poor i n 25 (30%); follow-up durations were similar for the three outcome cat egories. The failure rate was 17% for the 1st year and averaged 2.6% e ach year thereafter. Two variables were predictive of a poor outcome: prior surgery and lack of preoperative involvement of the third trigem inal division. Major complications occurred in 4% of cases and minor c omplications in 11%. The authors conclude that partial sensory rhizoto my is a safe and effective alternative to microvascular decompression when neurovascular compression is not identified at operation or when microvascular decompression cannot be performed for technical reasons.