Outcome evaluation of decompression surgery combined with cerebellar tonsillectomy compared without cerebellar tonsillectomy for Chiari type I malformation patients

Background: Surgical intervention is an important treatment option to improve the prognosis for Chiari type I malformation (CM-I) patients. However, there is no consensus about surgical strategies. The article intends to evaluate the effect of decompression combined with or without cerebellar tonsillectomy in the treatment of CM-I.

Method: Following PRISMA's principles, Embase, PubMed, Web of Science, and Cochrane databases and references to relevant articles were searched to include only original articles on decompression combined with or without cerebellar tonsillectomy in CM-I patients. Through meta-analysis, the data on clinical improvement, radiological improvement, and complications were pooled.

Results: Nine articles, including 399 CM-I patients undergoing decompression alone and 343 undergoing decompression with cerebellar tonsillectomy, meet the inclusion standard. In comparison, the improvement rate of clinical symptoms or signs in patients with cerebellar tonsillectomy is higher and statistically significant (RR: 0.85, 95% CI: 0.75-0.95; P = 0.006). However, decompression with cerebellar tonsillectomy is also significantly higher in the incidence of postoperative complications (RR: 0.54, 95% CI: 0.36-0.80; P = 0.002). No statistical difference is discovered between the two groups in the improvement rate of syringomyelia (RR: 0.77, 95% CI: 0.57-1.03; P = 0.08).

Conclusions: Although decompression with cerebellar tonsillectomy is superior than decompression alone in clinical improvement for CM-I patients, it also faces a higher risk of postoperative complications. The reduction of syringomyelia in the two groups can be considered equally effective without significant differences. In the future, the results of the research require multicenter and large-scale randomized controlled trials to verify in clinical practice.

Trial registration: CRD42022321750 (PROSPERO).