Extensive reconstruction of cisterna magna facilitates the outcome of adults with Chiari malformation type 1: A multicenter cohort study.

PURPOSE: There is no consensus regarding the optimal posterior fossa decompression strategy for Chiari malformation type 1 (CM1). Herewith, we introduced the extensive reconstruction of cisterna magna (eRCM) surgical methods and compared its outcomes with bony decompression (BD) + duraplasty (DU) in adult CM1 patients.

METHODS

In this real-world, multicenter study, we enrolled consecutive aged ≥ 18 years CM1 patients who underwent surgical interventions. Included CM1 patients received BD+DU or eRCM which were determined by surgeons. Short/long-term results were assessed 3/18 months after discharging. The primary outcome was evaluated using the Chiari Malformation outcome scale (CCOS).

RESULTS

Between Jan. 2019 and Dec. 2022, 718 patients were enrolled (median age [IQR], 57.7 [25.9-68.4] years, 58.4% male). eRCM provided better primary outcomes than BD+DU at both long- (71.7% vs 63.1%, P = 0.042) and short- (72.8% vs 64.3%, P = 0.045) term follow-up. The reduced rate of syringomyelia was higher in eRCM patients than BD+DU at both eighteen (75.9% vs 66.3%, P < 0.001) or three (77.9% vs 70.4%, P < 0.001) months assessment. The improvement of CSF hydrodynamic parameters at outlet of 4th ventricle was significantly in eRCM patients. In eRCM patients, CCOS improvement and syringomyelia reduced were not associated with tonsils resection or cauterization.

CONCLUSION

The surgical method eRCM may provide better prognosis than BD+DU in CM1 patients. Whether tonsils resection or cauterization should be intraoperatively selected to ensure that smoothly CSF flow, from the outlet of 4th ventricle to bilateral Luschka foramina, could be observed.