Predictors for the benefit of selective dorsal rhizotomy

• SDR improves function through the reduction of spasticity in ambulatory children with cerebral palsy.
• SDR does not compromise muscle strength.
• No correlation was found between reduction of spasticity and increase in strength of the antagonists.
• The benefit of SDR may be estimated from preoperative age, GMFM and standard deviation score of BMI.

Selective dorsal rhizotomy (SDR) is a spasticity reducing treatment option for children with spastic cerebral palsy. Selection criteria for this procedure are inconclusive to date. Clinical relevance of the achieved functional improvements and side effects like the negative impact on muscle strength are discussed controversially. In this prospective cohort study one and two year results of 54 children with a mean age of 6.9 (±2.9) years at the time of SDR are analyzed with regard to gross motor function and factors affecting the functional benefit. Only ambulatory children who were able to perform a gross motor function measure test (GMFM-88) were included in this study. Additionally, the modified Ashworth scale (MAS), a manual muscle strength test (MFT), and the body mass index (BMI) were evaluated as possible outcome predictors. MAS of hip adductors and hamstrings decreased significantly (p < 0.001) and stayed reduced after two years, while GMFM improved significantly from 79% to 84% 12 months after SDR (p < 0.001) and another 2% between 12 and 24 months (p = 0.002). Muscle strength did improve significantly concerning knee extension (p = 0.008) and ankle dorsiflexion (p = 0.006). The improvement of function correlated moderately with age at surgery and preoperative GMFM and weakly with the standard deviation score of the BMI, the dorsiflexor and plantarflexor strength preoperatively as well as with the reduction of spasticity of the hamstrings and the preoperative spasticity of the adductors and hamstrings. Correctly indicated SDR reduces spasticity and increases motor skills sustainably in children with spastic cerebral palsy corresponding to clinically relevant changes of GMFM without compromising muscular strength. Outcome correlates to GMFM and age rather than to MAS and maximal strength testing. The data of this evaluation suggest that children who benefit the most from SDR are between 4 and 7 years old and have a preoperative GMFM between 65% and 85%.