1334. Reoperation After Suboccipital Decompression With and Without Dural Opening in Children with Chiari Malformation Type 1

Authors: Samuel Butensky; Shaun Rodgers, MD; Shanna Baron, MD; Steven Schneider, MD; Mark Mittler, MD (Mineola, NY)

Introduction: Chiari malformation type I (CMI) is a congenital deformity in which the cerebellar tonsils herniate 5 mm or more below the foramen magnum. Surgical intervention by posterior fossa decompression is indicated for symptomatic patients with radiographic evidence of CMI. The purpose of this study was to compare clinical outcomes and risk factors for reoperation for posterior fossa decompression with and without dural opening. Methods: A retrospective analysis was performed on 178 consecutive cases of 157 patients undergoing posterior fossa decompression for CMI at Cohen Children’s Medical Center between 2007 and 2017. The study included 85 males and 93 females with a mean age of 12.5 ± 5.33 years and range of 1 to 26 years. Clinical improvement was defined as less symptoms after surgery than before surgery. Qualitative improvement of syrinx was derived from radiology reports. Results: There was no statistically significant difference between clinical improvement for posterior fossa decompression without dural opening (PFD) versus posterior fossa decompression with dural opening (PFDD) (p = 0.705). There was no significant difference in number of patients who underwent reoperation between PFD and PFDD (p = 0.835). Risk factors for reoperation after receiving PFD include presenting syrinx (p = 0.089), preoperative scoliosis (p = 0.189), and posterior headache (p = 0.052). After multivariate analysis, posterior headache remained a significant risk factor for revision duraplasty after PFD (p = 0.021). Risk factors for reoperation after receiving PFDD include male (p = 0.084) and extremity weakness (p = 0.059). After multivariate analysis, no risk factors were significant for revision duraplasty after PFDD. Conclusion: PFD has similar rates of clinical improvement and reoperation as compared to PFDD. Risk factors for reoperation differ between surgical approaches. A prospective study is needed to identify the ideal clinical population for each surgical approach.