Operative outcomes of Chiari I malformation at 2 specialist neurosurgical units in Addis Ababa, Ethiopia: A retrospective cross-sectional study

Abstract

Background: Chiari I malformation (CM1) is characterized by herniation of the cerebellar tonsils through the foramen magnum (FM) into the cervical spinal canal. To the authors best knowledge there are few papers on the outcomes of surgically treated CM1 patients in sub-saharan Africa.

Objective: This study assesses the outcomes of surgically treated Chiari I malformation (CM1) patients using the Chicago Chiari Outcome Scale (CCOS) and identifies factors affecting outcome.

Methods: A retrospective study was conducted among patients who underwent posterior fossa decompression (PFD) surgery at two teaching hospitals from January 1, 2010 to May 31, 2018. Surgical outcome was described using the CCOS and further analysis was done using SPSS version 25.0.

Results: The mean age at surgery was 27.4 years with males and females being equally affected. The mean follow up period was 22.9 months. The mean total CCOS score was 12.18 (range,8-16). Overall, 47.1% of our patients had a final CCOS score between 13 and 16. Tonsillar descent more than 14mm below FM (P=0.008), absence of syrinx (P=0.03) and female sex (P=0.037) were correlated with good to excellent surgical outcome (i.e. CCOS ≥ 13). The overall complication rate was 31.6%  and one patient died during the follow up period of x months(mortality rate, 2.9%).

Conclusions: PFD is an effective and safe treatment for patients with symptomatic CM1 or CM1 associated syringomyelia. Nonetheless, a significant number of our patients remained unchanged (i.e. CCOS score between 9 and 12) following surgery.