353 Cerebellar Tonsil Reduction for Surgical Treatment of Chiari I Malformation in Children

Abstract

INTRODUCTION: There remains much debate around ideal surgical technique for Chiari Malformation Type 1. Although recent trends favor less invasive techniques, growing evidence may support tonsillar reduction via resection or coagulation. METHODS: We retrospectively reviewed 456 consecutive children (<18 years of age) surgically treated for Chiari I malformation. Procedures were classified into four groups: bone decompression (PFD) and duraplasty (PFDD), PFDD with arachnoid dissection (PFDD + AD), PFDD with coagulation of at least one cerebellar tonsil (PFDD + TC) and PFDD with subpial resection of at least one tonsil (PFDD + TR). RESULTS: Preoperatively, univariate analysis showed that brainstem/spinal cord symptoms, use of cine MRI, tonsil length, and distance from the opisthion to brainstem were correlated with the surgical technique used. Multivariate analysis demonstrated that only tonsil length was independently associated with surgical technique choice: it was directly associated with utilization of PFDD + TR over PFDD (p = 0.001) or PFDD + AD (p = 0.005) and with PFDD + TC over PFDD (p = 0.005). Postoperatively, symptoms improved in 56/71 (78.9%) of patients in the PFDD group, 23/26 (88.5%) in PFDD + AD, 77/92 (83.7%) in PFDD + TC and 235/267 (88.0%) in PFDD + TR. Syringomyelia improved greater than 50% in 80.4% of patients in PFDD + TC/TR versus only 58.8% of PFDD + D/AD (p = 0.001). Reoperation rates and postoperative headaches were decreased (3.1% and 14.5%, respectively) in the PFDD + TC/TR group compared to the PFDD + D/AD group (8.3% and 25.8%, respectively), and they were both statistically significant (p-value = 0.023 and 0.008, respectively). Postoperative complication rates were not statistically different between the groups. CONCLUSIONS: In this single center retrospective series, cerebellar tonsil reduction, by either coagulation or sub-pial resection, results in superior reduction of syringomyelia in Chiari I patients with less reoperations and without increased complications.