Limited selective posterior rhizotomy for the treatment of spasticity secondary to infantile cerebral palsy: a preliminary report. A limited selective posterior rhizotomy was performed on 30 children suffering from spasticity secondary to infantile cerebral palsy. As opposed to standard techniques that stimulate and divide the dorsal rootlets from L2 to S1, we dissected L4, L5, and S1 dorsal roots through an L5 to S1 laminectomy. Eight to 12 rootlets from each root were electrically stimulated with two unipolar electrodes (pulse width, 50 microseconds; 10-50 V). The muscle responses were observed visually and registered by electromyography. Those rootlets associated with an abnormal motor response as evidenced by sustained muscular contraction or by prolonged electromyographic response were divided. Spasticity was scored from 0 to +. The muscular groups assessed were those involved in the flexion of the shoulder, elbow and wrist in the upper limbs, and those involved in flexion and adduction of the hip, flexion of the leg, and plantar flexion in the lower limbs. The patients were assessed 1 week before and 6 months after the operation. Reduction of spasticity was observed in all the muscular groups, and all the patients presented functional improvement of motor abilities. These preliminary results indicate that a limited procedure that reduces the extension of the laminectomy and the length of the operation could be effective for treating spasticity secondary to infantile cerebral palsy. 