Novel Risk Calculator for Suboccipital Decompression for Adult Chiari Malformation

Patient counseling and selection for surgical therapy in adult Chiari malformation type I (CM-1) remain debatable. We aimed to develop a clinical calculator predicting the risk of nonhome discharge and reoperation using the American College of Surgeons-National Surgical Quality Improvement Program database.

The database from years 2011 through 2017 was queried to identify the subset of CM-1 patients undergoing suboccipital decompression. Univariable analysis was conducted to identify baseline factors associated with nonhome discharge and 30-day reoperation following the initial decompression procedure. Logistic regression and the Akaike Information Criterion were used to identify the optimal models predictive of both outcomes. Performance was assessed using receiver operating curves and validated with bootstrapping.

In 706 CM-1 patients, the rate of nonhome discharge was 5.2% and the reoperation rate was 6.6% with most reoperations consisting of cerebrospinal fluid flow diversion and cerebrospinal fluid leak repair. The optimal model predictive of nonhome discharge consisted of age (odds ratio [OR] = 1.05, P = 0.001), diabetes (OR = 2.44, P = 0.080), and American Society of Anesthesiologists class (OR = 1.94, P = 0.082) with an area under the curve of 0.720. The optimal model predictive of reoperation consisted of female sex (OR = 0.48, P = 0.031), body mass index (OR = 1.05, P = 0.002), and ASA class (OR = 3.44, P = 0.001) with an area under the curve of 0.726. A calculator for both outcomes was deployed under the following URL: https://jhuspine3.shinyapps.io/Discharge_Reop_Calculator/.

We have used a large international database to develop a simple risk calculator based on readily available preoperative variables. Following subsequent validation, this tool can help optimize patient counseling and decision making in adult CM-1.