Responsiveness and Uniqueness of the Pediatric Outcomes Data Collection Instrument Compared to the Gross Motor Function Measure for Measuring Orthopaedic and Neurosurgical Outcomes in Cerebral Palsy

The Pediatrics Outcomes Data Collection Instrument (PODCI) is a valid and reliable measure of functional health status in children with acute and chronic musculoskeletal disorders, including cerebral palsy (CP), but its responsiveness has not been documented specifically for this population. The Gross Motor Function Measure (GMFM) and the Pediatric Evaluation of Disability Inventory (PEDI) are the only two instruments validated specifically as evaluative measures for CP, and while widely used, they are limited by a ceiling effect when assessing higher-functioning children. The PEDI is further restricted to children who are 7 years old or less. The goal of this study was to evaluate the responsiveness, and secondarily the uniqueness, of the PODCI compared with the GMFM for evaluating surgical outcomes in CP. Changes in the GMFM and PODCI Parent forms were assessed at two time points in 64 children with spastic CP who underwent muscle-tendon lengthenings (MT; n = 22) or neurosurgical spasticity reduction consisting of either selective dorsal rhizotomy (SDR; n = 18) or intrathecal baclofen pump implantation (ITB; n = 11) or who had no surgery between assessments (n = 13). The GMFM Total score was responsive to change after both MT surgery and SDR, with a nearly equivalent magnitude of change in both groups. However, the PODCI Global Function Scale was responsive to changes only after MT surgery, with improvement in the Sports and Physical Function subscale particularly prominent. No significant changes were noted in the ITB group for either measure.