Does spasticity affect outcomes in patients with cerebral palsy undergoing posterior spinal fusion?

PURPOSE: We evaluated whether the type of cerebral palsy (CP) (spastic vs. ataxic-hypotonic) affected outcomes in patients who underwent posterior spinal fusion (PSF). METHODS: We queried CP patients from 2008-2020 with GFMCS grade IV or V who underwent PSF with at least 2 years' follow-up. Demographic, radiographic, operative and CPCHILD scores were compared. We performed a matched comparison of patients with spasticity (SP) versus patients with ataxia-hypotonia (AH) by age and coronal curve angle. RESULTS: From 390 CP patients, 309 (79%) were spastic, 20 (5%) ataxic-hypotonic, 11 (3%) dystonic, and 50 (13%) mixed. When comparing matched SP to AH patients, preoperative demographic and radiographic variables were comparable except that SP patients had greater pelvic obliquity (27° vs. 20°, p<0.05), while postoperative pelvic obliquity (9° vs. 6°, p<0.01) was less at 1 and 2 years in the AH group. While surgical time was not different between groups (p>0.05), estimated blood loss (1465±1114 mL vs. 905±798 mL, p<0.01), postoperative pain (8% vs. 0%, p<0.01), and implant prominence (5% vs. 0%, p<0.01) were higher in the SP group. The overall reoperation rates were not different between groups (p>0.05), although the incidence of broken implants (20% vs. 2%, p<0.05) was higher in the AH group and reoperations due to implant failure were higher in the SP group (4% vs. 0%, p<0.05). CONCLUSIONS: Patients with spastic CP experienced higher blood loss, more postoperative pain, and greater implant prominence while patients with ataxic-hypotonic CP had less pelvic obliquity but experienced more broken implants.