Next, we have Dr. Nadel, Incidents of Cervical Medullary Decompression in Patients with Achondroplasia at a Large National Database Analysis. Thank you so much to the committee for allowing us to present our study on screening and surgery for foramen magnum stenosis in children with achondroplasia. My name is Jeff Nadel. I'm a fourth-year medical student at the University of Michigan, and I'm excited to be here with you. I have no relevant financial disclosures, and this study was supported by an NIH training grant that I was on for the past year. So, to begin, the neurologic sequelae in achondroplasia includes conditions commonly such as congenital spinal stenosis, macrocrania, and foramen magnum stenosis. And in the case of foramen magnum stenosis, cervical medullary decompression has been described as a common intervention to alleviate the signs and symptoms associated. However, on a population scale, the rates at which this intervention occurs have been difficult to ascertain because the majority of studies have been single-center case series of which rates of intervention are biased in the direction of patients who are actually seeking neurosurgical attention. Additionally, in 2005, the American Academy of Pediatrics revised its existing screening recommendations for foramen magnum stenosis in patients with achondroplasia and currently recommend neuroimaging and polysomnography by approximately one year of age for these patients. So, this leaves our field with a couple of questions, including, one, what proportion of infants with achondroplasia will go on to have cervical medullary decompression? And two, are the current AAP screening recommendations being followed on a population scale? In order to answer these questions, we used the OptumInsight dataset, which is a longitudinally linked large insurance claims database of privately insured enrollees in the U.S. of over 58 million patients. And in order to identify patients with achondroplasia as well as relevant screening and surgical procedures, we used a combination of ICD-9 diagnosis and CBT codes. The prevalence of achondroplasia within the OptumInsight dataset was 1.43 per 10,000 enrollees, which is in line with current estimates that are in the United States in the literature at this time. Within our cohort as well, we had 3,577 children with achondroplasia. And among those 3,500 children, the incidence rates of surgery varied significantly by age, where the rate of decompression was highest in infancy at approximately 2.75 percent in the cohort between zero and three. And the rate dropped significantly with increasing age. Summed across the entire childhood spectrum, the cumulative incidence rate of cervical medullary decompression was 3.3 percent. Additionally, in order to answer our question about whether screening was being adhered to in the United States, we selected a subset of our patients who had coverage beginning at birth and lasting for at least 18 months. And this was important because we needed to pick up everybody who may have had any sort of screening intervention during that time. Our results demonstrated that approximately 42 percent of patients received some form of screening with either neuroimaging or polysomnography. But 13.9 percent of patients were fully screened with both of those in adherence with the 2005 AAP guidelines. Interestingly and encouragingly, after the revision of the 2005 guidelines, we see that the screening rate went up significantly, indicating that the release of some of these guidelines does have the capacity to impact practice patterns. So in conclusion, among children with achondroplasia, across their entire childhood, the cumulative incidence rate of cervical medullary decompression is 3.3 percent, driven largely by that rate early in childhood. And screening is more common now than it was before 2005, but doesn't meet the standard that was outlined by the AAP. I'd like to thank all of my research mentors and advisors for the opportunity to conduct this work, and I'd be happy to take any questions. Thank you.

Dr. Jeff Nadel

foramen magnum stenosis

achondroplasia

cervical medullary decompression

screening recommendations