Inpatient outcomes of posterior fossa decompression with or without duraplasty for Chiari malformation type I

Objective: Chiari malformation type 1 (CM-1) is a congenital neurologic condition in which the cerebellar tonsils herniate below the foramen magnum, resulting in symptoms such as headache and neck pain. Two common surgical treatment approaches are posterior fossa decompression with (PFDD) and without duraplasty (PFD). Previous single-center studies have demonstrated increased neurologic complications after PFDD compared to PFD. The goal of this study is to determine differences in inpatient complications and hospitalization data among patients treated with these surgical techniques using a nationwide sample. Methods: The National Inpatient Sample (NIS) was queried for years 2012-2015 for all patients with a primary diagnosis of CM-1 who underwent PFD or PFDD. Differences in baseline demographics and comorbidities were accounted for in subsequent analysis using propensity score matching. Hospitalization measures and inpatient complications of the two cohorts were compared using Chi-squared tests and t-tests when appropriate. Results: A total of 2395 patients with CM-1 were included in this study, with 750 (31.3%) undergoing PFD and 1645 (68.7%) undergoing PFDD. PFDD was associated with higher total hospital costs than PFD. There were no significant differences in other hospitalization or discharge data, non-neurologic complications, or CNS complications (CSF leak, pseudomeningocele, abscess, meningitis, stroke) between the two surgical groups. Conclusions: This study represents the largest national analysis to date of adult CM-1 patients undergoing PFD or PFDD. Our findings suggest that whether the decision is made to perform the less invasive PFD or more invasive PFDD, inpatient complications and hospitalization data will not significantly differ.