297 Why Do Lipomyelomeningoceles Retether: 27 Years of Single-Institution Experience

INTRODUCTION: Lipomyelomeningoceles and recurrent tethered cord syndrome (TCS) represent a significant challenge in the management of these complex patients, necessitating an understanding of the risk factors that predict recurrence after initial surgical intervention. METHODS: Retrospective review was performed on pediatric patients with complex spinal lipomas who underwent tethered cord release by six attending surgeons at a single institution from 1996-2023. Demographics, operative, and long-term outcomes were collected. Lipomas were classified as transitional, dorsal, and caudal subtypes. Simple filum lipomas were excluded. Variables were analyzed for predictors of tethered cord recurrence. RESULTS: 104 patients with complex spinal lipoma underwent an initial tethered cord release. The median age was 6 months (1-284) and 51% were male. 83% of patients were asymptomatic and treated in a prophylactic manner. Lipoma subtype was transitional in 50%, dorsal in 40%, and 10% caudal. Gross or near total resection was achieved in 32% of cases. Intraoperative laser assistance was used in 67%. Average operative time was 167 minutes and estimated blood loss 13 mL. Surgical complications occurred in 12% of cases. Over 85 months (7 years) of mean follow-up (1-228), 17% of patients underwent a repeat operation for recurrent tethered cord syndrome 80 months (8-186) after initial surgery. Risk factors associated with recurrence included transitional subtype (p=0.003), surgical complications (p=0.003) and length of follow-up (p<0.0001). Age at presentation, symptomatic presentation, use of intraoperative laser, and extent of resection were not associated with recurrence risk. CONCLUSIONS: Transitional lipomas are more likely to retether over time. Prioritizing the reduction of surgical complications, rather than achieving complete resection, is more effective at reducing recurrence risk. Extended follow-up time in the recurrent cohort underscores the importance of long-term follow-up in these patients.