Clinical Patterns, Surgical Management and Outcomes of Chiari-1 Malformation (CM1): Experience at a Tertiary Hospital in Kenya

Abstract

The clinical presentation of Chiari-1 Malformation (CM1) is diverse. Surgical treatment involves posterior fossa decompression with variability in techniques of duraplasty, tonsillar management, and syrinx drainage if indicated. Assessment of outcome is important in evaluating the success of your surgical interventions. Methods: This study retrospectively examined patients with CM1 who underwent surgery at Kenyatta National Hospital between 2019 and 2024, analyzing demographics, clinical findings, and surgical interventions. Surgical outcome was determined using the Chicago Chiari Outcome Scale (CCOS). Results: 23 patients were included in the study. The median (IQR) age was 31.0 (23.0, 39.0) years; 65% (15) were male and 35% (8) were female. The median (IQR) tonsillar herniation was 11 (9.0, 17.0) mm. 61% (14) of patients had syringomyelia. The commonest presentation was Valsalva headaches (82.6%), limb weakness (60.9%), and numbness (43.5%), with an average duration of 16.5 months, 6.2 months, and 2.4 months, respectively. All patients underwent posterior fossa decompression with removal of the posterior arch of C1 and duraplasty (87% pericranium graft, 13% artificial dura graft). 39.1% of patients had subpial tonsillar coagulation, 17.4% had subpial tonsillectomy, while 43.5% had no tonsillar manipulation. The average follow-up duration was 18.8 months. The median (IQR) CCOS score was 14 (12.5, 15.0). 13% of patients had an excellent outcome, 83% had a functional outcome while 4% had an impaired outcome. There was no statistically significant association between surgical technique and outcome. Conclusion: Clinical improvement was noted in all patients following decompressive surgery, despite variability in surgical technique. The CCOS remains a reliable, standardized tool for outcome assessment in patients with CM1.