Chiari Malformation 1 with Syrinx? Do We Need to Fix It – Our Institutional Experience

Abstract Background: Chiari malformation (CM) is a spectrum of disorders associated with impaired cerebrospinal fluid (CSF) circulation through the foramen magnum, often presenting with syringomyelia (SM). While foramen magnum decompression (FMD) is the widely accepted treatment, the role of C1-C2 fixation remains underexplored. Objective: This study aimed to evaluate the regression of syrinx and clinical outcomes in patients with CM undergoing FMD alone versus FMD combined with C1-C2 fixation. Methods: A retrospective analysis of 48 patients diagnosed with CM-1 and syringomyelia treated at our institution from January 2012 to January 2020. Patients were grouped based on surgical intervention: FMD alone (with or without duraplasty) or FMD + C1-C2 fixation. Outcomes were assessed using postoperative imaging and the Chicago Chiari Outcome Scale (CCOS). Results: FMD alone led to >50% syrinx regression in 74.3% of patients without duraplasty and 84.3% with duraplasty, averaging 8 months. FMD + C1-C2 fixation demonstrated >75% regression in 85.7% of cases within 2 months. Faster recovery and significant syrinx resolution were noted in the fixation group. Conclusion: The findings suggest that FMD + C1-C2 fixation may offer faster syrinx regression and clinical recovery in isolated CM-1 cases, questioning the routine need for duraplasty. Further studies are needed to validate these results.