CLINICAL ARTICLE J Neurosurg Pediatr 23:374–380, 2019 A chondroplAsiA is the most common form of in- fantile skeletal dysplasia, with a reported preva- lence rate ranging from 0.36 to 1.5 per 10,000 individuals. 17,29 Neurological sequelae may present in as many as 47% of patients with achondroplasia 22 as a result of congenital spinal stenosis, foramen magnum stenosis, and macrocrania with or without hydrocephalus. 5,6,8,9,13,22,31 Among these abnormalities, foramen magnum and high cervical spinal stenosis are the most concerning, given that the resultant brainstem compression has been implicated in central sleep apnea and sudden infant death. 7,10,18,19,26,30 To this point, numerous single-center case reports and case series have described the role and safety profle of cervicomedullary decompression for foramen magnum stenosis in children with achondroplasia. 2,3,11,14,16,23–25,32,33 It is now widely considered the standard of care for children exhibiting signs and symptoms of foramen magnum com- pression. 28 However, given the infrequency with which any one center performs this procedure, it has been diffcult to ascertain how many children with achondroplasia will eventually require cervicomedullary decompression and at what time in life. Understanding the natural history of ABBREVIATIONS AAP = American Academy of Pediatrics; CPT = Current Procedural Terminology. SUBMITTED July 3, 2018. ACCEPTED September 26, 2018. INCLUDE WHEN CITING Published online December 14, 2018; DOI: 10.3171/2018.9.PEDS18410. Screening and surgery for foramen magnum stenosis in children with achondroplasia: a large, national database analysis Jeffrey L. Nadel, MS, 1 D. Andrew Wilkinson, MD, 2 Hugh J. L. Garton, MD, MSc, 2 Karin M. Muraszko, MD, 2 and Cormac O. Maher, MD 2 1 School of Medicine and 2 Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan OBJECTIVE The goal of this study was to determine the rates of screening and surgery for foramen magnum stenosis in children with achondroplasia in a large, privately insured healthcare network. METHODS Rates of screening and surgery for foramen magnum stenosis in children with achondroplasia were deter- mined using de-identifed insurance claims data from a large, privately insured healthcare network of over 58 million benefciaries across the United States between 2001 and 2014. Cases of achondroplasia and screening and surgery claims were identifed using a combination of International Classifcation of Diseases diagnosis codes and Current Pro- cedural Terminology codes. American Academy of Pediatrics (AAP) practice guidelines were used to determine screen- ing trends. RESULTS The search yielded 3577 children age 19 years or younger with achondroplasia. Of them, 236 met criteria for inclusion in the screening analysis. Among the screening cohort, 41.9% received some form of screening for foramen magnum stenosis, whereas 13.9% of patients were fully and appropriately screened according to the 2005 guidelines from the AAP. The screening rate signifcantly increased after the issuance of the AAP guidelines. Among all children in the cohort, 25 underwent cervicomedullary decompression for foramen magnum stenosis. The incidence rate of under- going cervicomedullary decompression was highest in infancy (28 per 1000 patient-years) and decreased with age (5 per 1000 patient-years for all other ages combined). CONCLUSIONS Children with achondroplasia continue to be underscreened for foramen magnum stenosis, although screening rates have improved since the release of the 2005 AAP surveillance guidelines. The incidence of surgery was highest in infants and decreased with age. https://thejns.org/doi/abs/10.3171/2018.9.PEDS18410 KEYWORDS achondroplasia; screening; foramen magnum stenosis; cervicomedullary decompression; pediatrics; congenital J Neurosurg Pediatr Volume 23 • March 2019 374 ©AANS 2019, except where prohibited by US copyright law Unauthenticated | Downloaded 05/16/22 08:54 PM UTC