Abstract
Children with cerebral palsy (CP) have an increased risk of progressive hip displacement. While the cause of hip displacement remains unclear, spasticity and muscle imbalance around the hip are felt to be a major factor. There is strong evidence demonstrating that a selective dorsal rhizotomy (SDR) reduces spasticity. However, the impact of this decreased spasticity on hip displacement is unknown. Past studies, which are small and lack long-term follow-up, do not provide a clear indication of the effect of SDR on hip displacement. The purpose of this study was to determine the influence of SDR on hip displacement in children with CP a minimum of five years post-SDR.
A retrospective chart review was completed. Participants were selected from a consecutive series of children who had an SDR before January 1, 2013 at one tertiary care facility to ensure a minimum five year follow-up. Pre-operative and minimum five year post-SDR AP pelvis radiographs were required for inclusion. Hip displacement was evaluated using change in MP between radiographs completed pre-SDR and minimum five years post-SDR, or until orthopaedic hip surgery.
In total, 77 participants (45 males, 32 females) at GMFCS levels of I (1), II (11), III (22), IV (35) and V (8) were included in the review. Mean age at time of SDR was 5 years (2.8– 11.6yrs). Pre-SDR mean MP of the 154 hips was 29% (0–100%). Post-SDR, 67 (43.5%) hips in 35 children had soft tissue, reconstructive, or salvage hip procedures at an average of 4.9 years (0.5–13.8yrs) post-SDR and an average MP of 46% (11–100%). In addition, seven hips (5%) had a MP ≥ 40% (40–100%) at most recent radiographic review that averaged 11 years (5.6–18.6yrs). Overall, the total number of subjects with hip displacement measuring MP >40% or who had a surgical hip intervention, by GMFCS level, was: 0 (0%) at level I, 0 (0%) at level II, 20 (45%) at level III, 22 (59%) at level IV, and 5 (81%) at level V.
The incidence of hip displacement in children with CP post-SDR did not substantially differ from the overall incidence reported in the literature when evaluated by GMFCS level. This study is the largest long-term follow-up study investigating the effect of hip displacement post-SDR. Results suggest that SDR does not impact hip displacement in CP, however, further prospective study will be required to strengthen the evidence in this regard.
