Long-term functional benefits of selective dorsal rhizotomy for spastic cerebral palsy

Abstract

Large-scale natural history studies of gross motor development have shown that children with spastic cerebral palsy (CP) plateau during childhood and actually decline through adolescence. Selective dorsal rhizotomy (SDR) is a well-recognized treatment for spastic CP, but little is known about long-term outcomes of this treatment. The purpose of this study was to assess the durability of functional outcomes in a large number of patients through adolescence and into early adulthood using standardized assessment tools. The authors analyzed long-term follow-up data in children who had been evaluated by a multidisciplinary team preoperatively and at 1, 5, 10, and 15 years after SDR. These evaluations included quantitative, standardized assessments of lower-limb tone (Ashworth Scale), Gross Motor Function Measure (GMFM), and performance of activities of daily living (ADLs) by the Pediatric Evaluation of Disability Inventory in children who had been stratified by motor severity using the Gross Motor Function Classification System (GMFCS). In addition, group-based trajectory modeling (GBTM) was used to identify any heterogeneity of response to SDR among these treated children, and to find which pretreatment variables might be associated with this heterogeneity. Finally, a chart review of adjunct orthopedic procedures required by these children following SDR was performed. Of 102 patients who underwent preoperative evaluations, 97, 62, 57, and 14 patients completed postoperative assessments at 1, 5, 10, and 15 years, respectively. After SDR, through adolescence and into early adulthood, statistically significant durable improvements in lower-limb muscle tone, gross motor function, and performance of ADLs were found. When stratified by the GMFCS, long-lasting improvements for GMFCS Groups I, II, and III were found. The GBTM revealed 4 groups of patients who responded differently to SDR. This group assignment was associated with distribution of spasticity (diplegia was associated with better outcomes than triplegia or quadriplegia) and degree of hip adductor spasticity (Ashworth score < 3 was associated with better outcomes than a score of 3), but not with age, sex, degree of ankle plantar flexion spasticity, or degree of hamstring spasticity. In a sample of 88 patients who had complete records of orthopedic procedures and botulinum toxin (Botox) injections, 52 (59.1%) underwent SDR alone, 11 (12.5%) received only Botox injections in addition to SDR, while 25 patients (28.4%) needed further lower-extremity orthopedic surgery after SDR. In the majority of patients, the benefits of SDR are durable through adolescence and into early adulthood. These benefits include improved muscle tone, gross motor function, and performance of ADLs, as well as a decreased need for adjunct orthopedic procedures or Botox injections. The children most likely to display these long-term benefits are those in GMFCS Groups I, II, and III, with spastic diplegia, less hip adductor spasticity, and preoperative GMFM scores greater than 60.