Chiari I Malformation: Review and Update of Current Treatment Options

The pathophysiology of Chiari malformation type I (CM-I) is complex, involving structural abnormalities at the craniovertebral junction that result in herniation of the cerebellar tonsils through the foramen magnum. In this study, we aim to present and evaluate current treatment options for CM-I, with a focus on evidence-based clinical outcomes and emerging surgical techniques. A comprehensive literature review was conducted using a PubMed search with MeSH terms such as "Arnold-Chiari Malformation, Type 1," "syringomyelia," and "Arnold-Chiari malformation*/surgery." Original research articles, case reports, systematic reviews, literature reviews, and meta-analyses in English discussing treatments, surgical techniques, anatomical variations, and clinical outcomes were identified to assess the indications, efficacy, and outcomes of various CM-I management strategies. A total of 108 articles were included in the final review, with the majority being retrospective cohort studies, case series, and systematic reviews. Posterior fossa decompression remains the standard surgical treatment of CM-I, with caveats. There is substantial variability in surgical techniques, particularly in clinical decision-making regarding the use of duraplasty, arachnoid dissection, and cerebellar tonsil reduction. Minimally invasive and endoscopic techniques are emerging and have demonstrated promising preliminary outcomes. For managing concurrent pathological conditions, such as hydrocephalus, craniocervical instability, and ventral brainstem compression, the surgical approach should be individualized according to patient-specific conditions. Management of CM-I requires a tailored, symptom-driven approach that should balance efficacy and safety. While posterior fossa decompression, with or without adjunctive surgical techniques depending on patient-specific clinical features and concomitant pathological conditions, remains the standard treatment option, minimally invasive procedures may represent promising alternatives and have shown favorable outcomes in selected patients.