Association between orthopedic manifestations and tethered cord release in patients with spina bifida: a survival analysis.

Abstract

Purpose: Patients with spina bifida (SB) are at risk for symptomatic tethered cord syndrome (TCS). Orthopedic decline, a common manifestation of TCS, is an indication for tethered cord release (TCR). Our objective is to determine if patients with SB who have undergone specific orthopedic operations (release of hip or knee contracture and correction of cavus foot) require TCR at a higher rate than those not undergoing these operations.

Methods: An institutional database was queried to identify all children with SB from 2009 to 2022. Data included functional level of lesion (FLOL), ambulatory status, and diagnosis of myelomeningocele (MMC) vs. closed neural tube defects. Survival analysis was performed to test the association between TCR and index orthopedic operations. Kaplan-Meier survival curves and multivariate Cox proportional hazard models were generated.

Results: There were 659 patients. Thirty-four (5.2%) had a history of orthopedic operation, and 625 (94.8%) had no history of orthopedic operation either before TCR or at last follow-up. Three of thirty-four (8.6%) in the orthopedic group underwent TCR after the orthopedic operation. Two hundred two of six hundred twenty-five (32.3%) in the non-orthopedic group underwent TCR. The adjusted hazard ratio (controlling for FLOL, ambulation, and diagnosis) was 3.8 (95% confidence interval 1.2-11). In MMC, the hazard ratio for the non-orthopedic group compared to the orthopedic group was 5.05 (95% confidence interval 1.2-20.7) which was significant.

Conclusion: Patients with MMC who underwent the specific orthopedic operations were significantly less likely to have subsequent TCR surgery. One possible explanation is that lower extremity deformity correction may alter surgeon behavior regarding TCR.