Article Abstract

Developments in the treatment of Chiari type 1 malformations over the past decade

Authors: Peter G. Passias, Alexandra Pyne, Samantha R. Horn, Gregory W. Poorman, Muhammad B. Janjua, Dennis Vasquez-Montes, Cole A. Bortz, Frank A. Segreto, Nicholas J. Frangella, Matthew Y. Siow, Akhila Sure, Peter L. Zhou, John Y. Moon, Bassel G. Diebo, Shaleen N. Vira


Background: Chiari malformations type 1 (CM-1), a developmental anomaly of the posterior fossa, usually presents in adolescence or early adulthood. There are few studies on the national incidence of CM-1, taking into account outcomes based on concurrent diagnoses. To quantify trends in CM-1 treatment and associated diagnoses. Retrospective review of the Kids’ Inpatient Database (KID) from 2003–2012.
Methods: Patients, aged 0–20, with primary diagnosis of CM-1 in the KID database were identified. Demographics and concurrent diagnoses were analyzed using chi-squared and t-tests for categorical and numerical variables, respectively. Trends in diagnosis, treatments, and outcomes were analyzed using analysis of variance (ANOVA).
Results: Five thousand four hundred and thirty-eight patients were identified in the KID database with primary diagnosis of CM-1 (10.5 years, 55% female). CM-1 primary diagnoses have increased over time (45 to 96 per 100,000). CM-1 patients had the following concurrent diagnoses: 23.8% syringomyelia/syringobulbia, 11.5% scoliosis, 5.9% hydrocephalus, 2.2% tethered cord syndrome. Eighty-three point four percent of CM-1 patients underwent surgical treatment, and rate of surgical treatment for CM-1 increased from 2003–2012 (66% to 72%, P<0.001) though complication rate decreased (7% to 3%, P<0.001) and mortality rates remained constant. Seventy percent of surgeries involved decompression-only, which increased neurologic complications compared to fusions (P=0.039). Cranial decompressions decreased from 2003–2012 (42.2–30.5%) while spinal decompressions increased (73.1–77.4%). Fusion rates have increased over time (0.45% to 1.8%) and are associated with higher complications than decompression-only (11.9% vs. 4.7%). Seven point four percent of patients experienced at least one peri-operative complication (nervous system, dysphagia, respiratory most common). Patients with concurrent hydrocephalus had increased nervous and respiratory systems, urinary, and respiratory complications (P<0.006) and syringomyelia increased the rate of respiratory complications (P=0.037).
Conclusions: CM-1 malformation diagnoses have increased in the last decade. Despite the decrease in overall complication rates, fusions are becoming more common and are associated with higher peri-operative complication rates. Commonly associated diagnoses including syringomyelia and hydrocephalus, can dramatically increase experienced complication rates.