Rootless century: posterior rhizotomy for spastic cerebral palsy.

‘The objective of this single center investigator-masked randomized clinical trial was to investigate the efficacy and safety of selective dorsal rhizotomy (SDR) in children with spastic diplegia. Forty-three children with spastic diplegia were randomized on an intention to treat basis to receive SDR plus physical therapy (PT), or PT alone. Thirty-eight children completed follow-up through 24 months. Twenty-one children received SDR (SDR þ PT group) and 17 received PT (PT Only group). SDR was guided with electrophysiologic monitoring and performed by one experienced neurosurgeon. All subjects received equivalent PT. Spasticity was quantified with an electromechanical torque measurement device (Spasticity Measurement System [SMS]). The Gross Motor Function Measure (GMFM) was used to document changes in functional mobility. Primary outcome measures were collected at baseline, six, 12, and 24 months by evaluators masked to treatment. At 24 months, the SDR þ PT group exceeded the PT Only group in mean reduction of spasticity by SMS measurement ( 8.2 vs. þ5.1 Newton-meters/radian, p 1⁄4 .02). the SDR þ PT group and the PT Only group demonstrated similar improvements in independent mobility on the GMFM (7.0 vs. 7.2 total percent score, p 1⁄4 .94). Outcomes on secondary variables were consistent with primary outcomes. There were no serious adverse events. We conclude that SDR is safe and reduces spasticity in children with spastic diplegia. SDR plus PT and equivalent PT without SDR result in equal improvements in the independent mobility at 24 months. . . .’’ The authors’ scientific conclusion was exceptionally conservative: ‘‘SDR may not be an efficacious treatment for children with mild spastic diplegia.’’ Two parallel studies during the same period failed the ‘‘randomized’’ prescription in many ways. Both evaluating and other staff members were quite aware of which children had selective dorsal rhizotomy. Evidently, the institutional structures, parents, and patients were prejudicially dedicated toward a successful judgment for the power of selective dorsal rhizotomy. Both groups reported selective dorsal rhizotomy improvement of the Gross Motor Function Measure, 6.1% and 7.7%. Meta-analysis, the deceptive concatenation of these specious data with those from the McLaughlin study, produced a small arithmetical effect on their combined Gross Motor Function Measure (4.0%). Recently MacWilliams et al described a remarkable retrospective study of teenage selective dorsal rhizotomy (mean age operation 14.5 years) compared with ‘‘similar children who had no surgery and with those who underwent orthopedic surgery. . . . Longitudinal comparisons of gross motor function demonstrated a decrease in the SDR group . . . worse outcomes of the SDR group compared with the orthopedic surgery and with the no surgical intervention group. . . . Interpretation: This suggests that age greater than 10 years might be a contraindication for SDR if the goal is to improve motor skills.’’ [What other rationale?] The designated editorial authors display popular opinion: ‘‘Selective dorsal rhizotomy (SDR) is now a well-accepted option for spasticity management in children with cerebral palsy. The evidence-base for this is provided by three classic randomized control trials and a subsequent meta-analysis. . . . Spasticity is the main factor compromising gait and motor function in children with cerebral palsy in early and middle childhood.’’ [vide supra] More important is the extended prospective study of first-decade rhizotomy by Tedroff et al: ‘‘AIM . . . to evaluate the long-term effects of SDR in children with CP. METHOD 19 children (4 female, 15 male; mean rhizotomy age 4y 7mo . . .) with bilateral spastic CP, prospectively assessed at baseline and 18 months, 3 years, and 10 years after SDR. Assessments include the Modified Ashworth Scale for spasticity [The standard/subjective Ashworth Scale lacks replicable validity.], the Gross Motor Function Measure 88 (GMFM-88) and the Wilson gait scale for ambulation, neurological investigations, and passive joint range of motion assessment. A 10-year retrospective chart review was added for orthopaedic surgery after SDR. RESULTS Baseline muscle tone at the hip, knee, and ankle level displayed a high degree of spasticity that normalized after SDR. After 10 years there was a slight recurrence of spasticity at the knee and ankle. Joint range of motion declined from a maximum at 3 years after SDR to the 10-year follow-up. Median ambulatory status was best 3 years after SDR and then declined. The GMFM-88 score increased from the median baseline value of 51 to 66 (p1⁄40.002) and 76 (p<0.001) at the initial follow-ups. After 10 years there was a decline in gross motor function with a reduction in the GMFM-88 score to 62 (p1⁄40.022). Within 10 years, 16 out of 19 patients had a mean of three orthopaedic surgeries (SD 2.8), soft tissue surgery being the most common. INTERPRETATION The spasticity-reducing effect of SDR, although pronounced, did not seem to improve long-term functioning or prevent contractures. This suggests that contracture development in CP is not mediated by spasticity alone.’’ I believe that these data argue for graduation of the modest conclusive verb ‘‘suggest’’ to ‘‘Q.E.D 1⁄4 proved.’’ However, the designated editorial reviewer argued for exceptionalism: ‘‘Some may interpret this incorrectly to indicate that there was no value to the SDR.’’ Indeed! I rather believe that there is sound rationale for belief that adaptive performance of the surgically injured nervous system, like the normal, improves over time as a function of normal use, growth, and maturation. If this hypothesis be so, it is reasonable to infer that early life mutilation of major afferent pathways can and evidently does impair normal mature integration of the human neuromotor system. 10 Journal of Child Neurology 28(1)