RESIDUAL SPASTICITY AFTER SELECTIVE POSTERIOR RHIZOTOMY

The technique used in performing selective posterior rhizotomies to tr eat spastic cerebral palsy remains controversial. One hundred nine chi ldren who had undergone selective posterior rhizotomies were studied 6 months after their surgery. Their residual spasticity was correlated to the number of roots and whether or not abnormally responding roots were left, in order to validate the surgical technique used to treat s pastic cerebral palsy at most neurosurgical centers in North America. The children were divided into three groups (group A: children who had their L2-S1 roots tested and selectively lesioned, n=15; group B: chi ldren who had their L2-S2 roots tested and selectively lesioned, n=62; group C: children who had their L2-S2 roots tested and whose lesionin g was directed both by the response to the stimulation and mapping of the S1-S3 dorsal roots for afferent pudendal nerve activity, n=32). Cl inically significant residual spasticity was present in the gastrocnem ius in 33% of the group A children, 11% of the group B children, and 6 % of the group C children. We found that there was no significant incr ease in residual spasticity in the group C children when abnormally re sponding roots were not cut in order to preserve pudendal nerve activi ty. This study shows that the inclusion of the S2 roots decreases the amount of residual spasticity (P<0.01). It also shows that leaving abn ormally responding S2 roots to preserve pudendal nerve activity does n ot affect the incidence of postoperative spasticity (P>0.1).