Extended Laminectomy in Chiari Malformation Treatment: A Systematic Review

Extended C2 laminectomy may expand the formation of the neocisterna magna in Chiari malformation (CM) surgery to improve cerebrospinal fluid (CSF) flow in the craniovertebral junction (CVJ). We aimed to clarify indications, outcomes, and complications of C2 laminectomy in CM. A systematic review (PROSPERO CRD42022340553) following the PRISMA protocol was performed in Pubmed, Web of Science, Cochrane, Embase, and Scopus databases with the Medical Subject Headings-based search strategy "("Arnold-Chiari Malformation") AND ("Decompression, Surgical" OR "Axis, Cervical") AND (Headache OR Vertigo OR "Deglutition Disorders")". The endpoints were symptom improvement and complication rates. Thirteen original articles included were case reports or series. The extent of laminectomy was directly related to the degree of tonsillar herniation. Six studies presented the perception of improvement (Gestalt) range from 83% to 100%. Three articles applied objective scales to report improvement in headache (VAS) and strength (MRC or ASIA). Nine studies reported complication rates. Fistula occurred in a range of 2% to 9.5% of cases. Three articles presented data on multilevel laminectomy for CM, and five studies reported on pediatric cases. Spine deformity was observed in children after wide multilevel laminectomy. This review showed a few concerns about C2 laminectomy. The descent of tonsilar herniation was the parameter for removing C2 lamina with good global results and complication rates. C2 laminectomy can be performed in young patients without previous instability. However, the lack of stratification of cases and systematization of the evaluation of results compromised the comparative analysis of the usefulness of C2 laminectomy in treating CM.