Risk Factors Portending Extended Length of Stay After Suboccipital Decompression for Adult Chiari I Malformation

Abstract

For adult patients undergoing surgical decompression for Chiari malformation type I (CM-I), the patient-level factors that influence extended length of stay (LOS) are relatively unknown. The aim of this study was to investigate the impact of patient-baseline comorbidities, demographics, and postoperative complications on extended LOS after intervention after adult CM-I decompression surgery. A retrospective cohort study using the National Inpatient Sample years 2010-2014 was performed. Adults (≥18 years) with a primary diagnosis of CM-I undergoing surgical decompression were identified. Weighted patient demographics, comorbidities, complications, LOS, disposition, and total cost were recorded. A multivariate logistic regression was used to determine the odds ratio for risk-adjusted LOS. A total of 29,961 patients were identified, 6802 of whom (22.7%) had extended LOS. The extended LOS cohort had a significantly greater overall complication rate (normal LOS, 10.6% vs. extended LOS, 29.1%; P < 0.001) and total cost (normal LOS, $14,959 ± $6037 vs. extended LOS, $25,324 ± $21,629; P < 0.001) compared with the normal LOS cohort. On multivariate logistic regression, black race, income quartiles, private insurance, obstructive hydrocephalus, lack of coordination, fluid and electrolyte disorders, and paralysis were all independently associated with extended LOS. Additional duraplasty (P= 0.132) was not significantly associated with extended LOS after adjusting for other variables. The odds ratio for extended LOS was 2.07 (95% confidence interval, 1.59-2.71) for patients with 1 complication and 9.47 (95% confidence interval, 5.86-15.30) for patients with >1 complication. Our study shows that extended LOS after adult CM-I decompression surgery may be influenced by multiple patient-level factors.