Effects of selective dorsal rhizotomy for spastic diplegia on hip migration in cerebral palsy

In spastic diplegia of cerebral palsy, migration of the femoral head beyond a lateral edge of the acetabulum is a common orthopedic deformity and requires surgical treatment. We investigated whether selective dorsal rhizotomy for spastic diplegia halts or exacerbates lateral hip migration. The Reimers migration percentage computed from preoperative and postoperative hip radiographs was used as an index of the severity of lateral hip migration in all 134 hips of 67 children examined. At the time of rhizotomy, 38 patients were between 2 and 4 years of age and 29 were between 5 and 11 years of age. The follow-up period ranged from 6 to 10 months in 20 patients and from 15 to 46 months in 47 patients. Overall, the MP remained unchanged in 75% decreased in 17% and increased in 7%; thus, 93% of all hips examined were stable radiographically. Although most patients experienced postoperative hip stability, there was a significant trend for patients with greater preoperative migration to show decreased postoperative migration. The preoperative ambulatory status of patients had no impact on hip stability after dorsal rhizotomy. By the last follow-up, only 1 patient had undergone orthopedic operations for a persistent hip deformity. The results suggest that in children with spastic diplegia, selective dorsal rhizotomy halts lateral hip migration in the great majority of cases.