Selective Dorsal Rhizotomy: Efficacy and Safety in an Investigator-Masked Randomized Clinical Trial.

McLaughlin JF, Bjornson KF, Astley S J, et al (Departments of Pediatrics, Epidemiology, Neurological Surgery, Rehabilitation Medicine, and Biostatistics, University of Washington, Seattle, Wash; Division of Congenital Defects and Department of Rehabilitation Medicine, Children's Hospital and Regional Medical Center, Seattle, Wash), Dev Med Child Neurol. 1998;40:220-232.

The primary purpose of this study was to determine if selective dorsal rhizotomy (SDR) plus intensive physical therapy would result in significant decreases in spasticity and increases in functional mobility in children with spastic diplegic cerebral palsy in comparison to intensive physical therapy alone. A secondary purpose of the study was to identify complications associated with this treatment and to identify characteristics that may predict a child's functional response to SDR. This study was carried out at a single center, using a prospective, investigator-masked design. Forty-three children with spastic diplegic cerebral palsy were randomly assigned either to a group that would receive SDR and intensive physical therapy (SDR+PT) or a group that would receive intensive physical therapy alone (PT Only).

At the start of the study, the participating children were between 3 and 18 years of age and met the eligibility criteria used to screen a group of 212 children between 1991 and 1994. Random assignment to the study groups was stratified by age and ambulatory status at the start of the study. Outcome variables included an electromechanical torque measure of the gastrocnemius muscle's resistance to stretching; scores on the Ashworth Scale; a clinical assessment of signs of spasticity (eg, deep tendon reflexes, clonus); the Gross Motor Function Measure (GMFM); range of motion of the lower extremities; and radiographs of the hips. These variables were measured at baseline and 6 months, 12 months, and 24 months after initiation of the assigned treatment. All SDR surgeries were performed by one surgeon who used a consistent technique. The intensive physical therapy program was (1) 2 hours per day, 5 days per week, for 4 weeks; then (2) 1 hour per day, 4 to 5 days per week, for 5 months; and finally (3) 1 hour per day, 1 to 4 days per week, for the next 6 months. Lower-extremity sensory assessments of the children in the SDR+PT group and a questionnaire sent to all subjects were used to detect adverse events. Thirty-eight children completed the 24-month study in the groups to which they were randomly assigned. Twenty-one children were in the SDR+PT group, and 17 children were in the PT Only group.

Outcome variables were evaluated by examiners who were not informed about group assignments. The outcome variables were analyzed using t tests for continuous variables, the [chi-square] or Fisher exact tests for categorical variables, or the Mann-Whitney U test where normal distribution could not be assumed. The SDR+PT group demonstrated substantial reductions in spasticity that lasted through the 24 months, whereas spasticity in the PT Only group did not change. No difference between groups was found in performance on the GMFM. No severe adverse effects were noted in either group.

The authors discussed the consistency of this study with other studies regarding reduction of spasticity with SDR, and its inconsistency with other current studies regarding functional change as measured by GMFM. They reported that the GMFM is known to be responsive and that its measurements are reliable for use with this population, and that their study size offered sufficient statistical power to support their findings. The authors proposed that, based on comparisons of baseline GMFM scores, the children in this study may have been more mildly involved than those of other studies. The authors concluded that SDR may not be as efficacious in children with mild spastic diplegic cerebral palsy as it is in those children with moderate spastic diplegic cerebral palsy and that the GMFM may not be as sensitive to change in its upper range as in its middle range.

Donna Cech, PT, PCS Midwestern University Downers Grove, Ill