Foramen Magnum Decompression and Duraplasty is Superior to Only Foramen Magnum Decompression in Chiari Malformation Type 1 Associated with Syringomyelia in Adults

STUDY DESIGN: Retrospective cohort study. PURPOSE: To compare surgical results of foramen magnum decompression with and without duraplasty in Chiari malformation type 1 (CM-1) associated syringomyelia (SM). OVERVIEW OF LITERATURE: The optimal surgical treatment of CM-1 associated with SM is unclear. METHODS: Twenty-five cases of CM-1 with SM were included. There were 12 patients (48%) in the non-duraplasty group and 13 patients (52%) in the duraplasty group. The rate of improvement, state of postoperative SM size, amount of tonsillar herniation, preoperative symptom duration, complications and reoperation rates were analysed. RESULTS: The rate of clinical improvement was significantly higher with duraplasty (84.6%) than without (33.3%, p <0.05). The rate of postoperative syrinx regression was significantly higher in the duraplasty group (84.6%) than in the non-duraplasty group (33.3%, p <0.05). One case in the duraplasty group needed a reoperation compared with five cases in the non-duraplasty group (p =0.059). CONCLUSIONS: Duraplasty is superior to non-duraplasty in CM-1 associated with SM despite a slightly higher complication rate.