Selective posterior rhizotomy for lower extremity spasticity: how much and which of the posterior rootlets should be cut?

BACKGROUND It is well known that selective posterior rhizotomy is effective for relieving spasticity associated with cerebral palsy. However, there is significant variation between surgeons in terms of how much and which of the posterior rootlets should be cut for the improvement of ambulatory function without causing adverse effects. METHODS The study population was composed of 200 CP patients who underwent SPR more than 1 year before this study. The children were divided into 4 groups (Group A had their L1-S2 roots cut, Group B had the L2-S2 roots cut, Group C had the L2-S1 roots cut, and Group D had the L2-S1 roots and the unilateral S2 root cut). We assessed lower limb spasticity, passive range of motion, ambulatory function, and gait pattern in each group. RESULTS Inclusion of L1 and S2 in the lesioning process of SPR was more effective at relieving spasticity in terms of hip adduction and ankle dorsiflexion respectively and improving ambulatory function ( p < 0.01). Although lesioning of S2 carried a greater risk of urinary dysfunction, resection of less than 50% of S2 significantly improved ambulatory function without urinary complications ( p < 0.01). Unilateral lesioning of S2 was an alternative option in selected cases with different amounts of spasticity in the ankles for the same purpose. CONCLUSIONS We propose that L1 and S2 roots should be included in the lesioning process of SPR for effective improvement of gross motor function, but that resection of these roots should be less than 50% to prevent complications.