Age as a predictor of reoperations and complications in surgically managed pediatric Chiari malformation type I

Chiari malformation type I (CM-I) is defined by the herniation of the cerebellar tonsils into the spinal canal. When symptomatic, surgical decompression is recommended. Reported CM-I reoperation rates have ranged from 3% to 30%. However, the relationship between patient age at first surgical intervention and the likelihood of reoperation and postoperative complications remains poorly characterized. Therefore, this study aimed to determine whether patient age was associated with reoperation and complication rates.

Patients 0-21 years old with a diagnosis of CM-I and surgical decompression were queried from the 2007-2021 MarketScan databases. Patient sex, age at time of first procedure, comorbidities, 90-day postoperative complications, and reoperations were identified. Bootstrap-augmented binary classifiers were constructed to determine the optimal timing of first surgical decompression with respect to all-cause 90-day postoperative complications and reoperation. Multivariate logistic regression models were built to assess the relationship between age, sex, and comorbidities and the likelihood of reoperation and complications following surgical decompression.

A total of 2675 patients were included for analysis of 90-day postoperative complications, and 1157 were included in the reoperation analysis cohort. A total of 524 patients (19.6%) experienced a complication within 90 days of surgical decompression, and 84 patients (7.3%) had reoperations. On multivariate regression, increased age was an independent predictor of a reduced likelihood of both reoperations (OR 0.94, 95% CI 0.90-0.98; p < 0.01) and 90-day postoperative complications (OR 0.96, 95% CI 0.94-0.98; p < 0.01). The optimal age cutoff to predict both complications and reoperations was 4 years. For patients ages 4 years and older, both the reoperation rate (5.5% vs 13.2%, p < 0.01) and 90-day postoperative complication rates (18.4% vs 27.7%; p < 0.01) were significantly less than those for children 3 years and younger.

In a national cohort of pediatric patients undergoing surgically managed CM-I, there was a significantly increased likelihood of reoperation and complications in patients ages 3 years and younger. Although CM-I decompression should not be postponed in the face of progressive neurological deficits, the authors' findings suggest that delaying surgery until after the age of 3 years, when medically feasible, may help mitigate adverse events.