Rib-on-pelvis deformity: a modifiable driver of pain and poor health-related quality of life in cerebral palsy

Purpose Cerebral Palsy (CP) often presents with a sweeping thoracolumbar scoliosis and pelvic obliquity. With severe pelvic obliquity, the ribs come into contact with the high side of the oblique pelvis, termed rib-on-pelvis deformity (ROP). ROP can result in costo-iliac impingement, or pain associated with ROP, and can also adversely affect breathing and sitting balance. The goal of this study was to evaluate whether CP patients with ROP have worse health-related quality of life (HRQOL) before surgery and a greater improvement in HRQOL after surgery. Methods A retrospective analysis of a prospectively collected, multicenter, international registry was performed for all nonambulatory patients with CP treated with spinal fusion with at least two-year follow-up. HRQOL was measured via the Caregiver Priorities & Child Health Index of Life with Disabilities (CPCHILD) questionnaire domains (0 = most disability, 100 = least disability). ROP was defined as having a rib distal to the superior portion of the iliac crest on preop upright radiographs. The ROP group and control group without ROP were compared regarding six domain scores and total score of CPCHILD. Multiple linear regression was used to control for curve apex location, major coronal Cobb angle, type of tone, and pelvic obliquity. Results 340 patients met inclusion criteria (52% female, mean age 14.0 years). The mean major coronal Cobb angle was 81 degrees and mean pelvic obliquity was 22 degrees. 176 patients (51.8%) had ROP while 164 patients (48.2%) did not. ROP was independently associated with worse preoperative Positioning/Transfers/Mobility (PTM), Comfort & Emotions (C&E), and total CPCHILD score via the CPCHILD questionnaire (p < 0.05). Patients with preoperative ROP experienced a greater improvement in the C&E and PTM domains as well as total CPCHILD score than patients without ROP (p < 0.05). Conclusion CP patients with rib-on-pelvis deformity experience more pain and worse HRQOL than patients without this deformity. These patients experienced a greater improvement in HRQOL after spinal fusion measured via the CPCHILD questionnaire.