187 Achondroplasia Natural History Study (CLARITY): 60-Year Experience With Hydrocephalus in Achondroplasia From Four Skeletal Dysplasia Centers

Abstract

INTRODUCTION: This study is the largest to date to look at the treatment of hydrocephalus in achondroplasia. METHODS: CLARITY (The Achondroplasia Natural History Study) is a registry for clinical data from achondroplasia patients receiving treatment at four skeletal dysplasia centers in the United States from 1957 to 2017. Data included surgeries with indications and complications, medical diagnoses, and radiographic information. RESULTS: 1374 patients with achondroplasia were included in this study. 124 (9%) of these patients underwent treatment of hydrocephalus at a median age of 14.6 months. There was wide variation by center and decade of birth, with treatment ranging from 0% to 28% of patients, although in the most recent decade, it fell to 3.4% of patients. Requiring cervicomedullary decompression (CMD) predicted treatment of hydrocephalus with an odds ratio of 5.8 (95% CI 3.9-8.4), although that association has disappeared in those born since 2010 with an odd’s ratio of 1.1 (95% CI 0.2-5.7). In patients born since 1990, treatment of hydrocephalus with an ETV has become more common. Kaplan Meier analysis suggests a single ETV will treat hydrocephalus in roughly half of these patients. CONCLUSIONS: While children with achondroplasia have enlarged intracranial CSF spaces and macrocephaly, treatment of hydrocephalus has become relatively unusual in the last twenty years. Historically there was a significant association between symptomatic foramen magnum (FM) stenosis and treatment of hydrocephalus, although concurrent treatment of both has fallen out of favor since CMD alone will treat hydrocephalus in some patients. While understood as communicating hydrocephalus, endoscopic third ventriculostomy (ETV) appears to be reasonably successful in certain patients and should be considered an option in selected patients.