Identification of risk factors for reconstructive hip surgery after intrathecal baclofen therapy in children with cerebral palsy

OBJECTIVE: This study aimed to determine the risk factors for reconstructive hip surgery after intrathecal baclofen pump application in children with cerebral palsy. METHODS: Inclusion criteria were children with hypertonic (spastic or mixed spastic/dystonic motor type) cerebral palsy, intrathecal baclofen implantation <8 years of age, no reconstructive osteotomies prior to or concomitant with intrathecal baclofen implantation and at least a 5-year follow-up. Exclusion criteria included reconstructive osteotomies prior to or concurrent with intrathecal baclofen implantation, lack of at least 1 hip surveillance radiograph before intrathecal baclofen, lack of a 5-year follow-up, or having selective dorsal rhizotomy. In addition, patients with bony surgery plus last follow-up migration percentage ≥50% were labeled as required reconstruction hips. RESULTS: We identified 34 patients (68 hips). The mean follow-up was 9.2 ± 2.8 years. The mean age for intrathecal baclofen application was 6.4 ± 1.2 years. Seven patients were Gross Motor Function Classification System IV, and 27 were V. Eighteen patients (52.9%) with 31 hips (45.6%) were requiring reconstruction at the final follow-up. In multivariate analysis, male sex (odds ratio 12.8, P = .012), pre-intrathecal baclofen migration percentage (odds ratio 1.1, P = 0.003), age at intrathecal baclofen implantation (odds ratio 0.24, P = .002), and delta migration percentage (odds ratio 1.1, P = .002) were significant risk factors for requiring reconstruction. Patients with intrathecal baclofen <6.2 years of age had a significantly higher rate of requiring reconstruction. A pre-intrathecal baclofen migration percentage >31% had a greater risk of progression to requiring reconstruction (P = .001). Delta migration percentage higher than 15% was significantly associated with progression to requiring reconstruction (P = .043). CONCLUSION: The risk of requiring reconstruction osteotomies after intrathecal baclofen was significantly increased in males, those younger (±migration percentage >31%) at the time of intrathecal baclofen implantation and those with an increased rate of migration percentage progression after intrathecal baclofen implantation. LEVEL OF EVIDENCE: Level IV, Prognostic Study