Lightning Podiums: Spinal Potpourri - 803B

Presented by: S. Horn


S. Horn(1), D. Vasquez-Montes(1), G. Poorman(1), F. Segreto(1), C. Bortz(1), C. Varlotta(1), N. Frangella(1), O. Bono(1), J. Buza(1), C.R. Goodwin(2), P. Passias(1)

(1) New York University Langone Orthopedic Hospital, Division of Spinal Surgery, New York, NY, United States
(2) Duke University Medical Center, Neurosurgery, Durham, NC, United States


Introduction: Chiari malformations are structural defects in the brain where the cerebellum is pushed downward into the foramen magnum and upper spinal canal. These malformations are classified by the severity of the disorder as Types 1-4, with each type presenting with different associated and/or concurrent conditions and anomalies. The aim of this study was to utilize a nationwide database to study the Chiari malformation patients with their concurrent diagnoses and associated anomalies.

Methods: This was a retrospective review of the prospectively collected Nationwide Inpatient Sample (NIS) database from 2003-2012. Chiari malformations were assessed by Chiari type using ICD-9-CM codes: Type 1 (ICD-9-CM 348.4), Type 2 (741.00-741.03), Type 3 (742.0), and Type 4 (742.2). NIS supplied hospital- and year-adjusted weights allowed for accurate assessment of prevalence of Chiari malformations, as well as cardiac and gastrointestinal (GI) and genitourinary (GU), and other body system anomalies. Rates of concurrence for the various body system anomalies were evaluated using cross-tabulations.

Results: There were 305726 national cases of Chiari Type 1, 119632 cases of Chiari Type 2, 15540 cases of Type 3, and 79663 cases of Type 4. Overall 44.3% of Chiari patients have at least one concurrent anomaly. Broken down by Chiari Type, 7.1% of Type 1 patients, 12.3% of Type 2, and 100% of Type 3 and Type 4 have at least one concurrent anomaly. For known associated conditions with Chiari, tethered cord was present in 1.9% of Type 1, 4.0% of Type 2, 0.7% Types 3 and 4, spina bifida in 0.8% Type 1 and 2.9% Types 3 and 4. In addition, syringomyelia was present in 4.6% of Type 1 cases, 2.8% Type 2, 0.7% Type 3 and 0.2% Type 4. The distribution of hydrocephalus presentation in Chiari cases was as follows: 13.1% Type 1, 1.1% Type 2, 10.6% Type 3, and 16.0% Type 4. The most common anomaly clusters for Chiari Type 1 were 0.63% presented with syringomyelia and scoliosis, 0.59% presented with Ehlers Danlos Sydrome and tethered cord syndrome, 0.34% presented with syringomyelia and tethered cord. In Type 2 patients, 0.72% presented with tethered cord syndrome and scoliosis, 0.43% with syringomyelia and scoliosis, 0.31% with atrial septal defect and patent ductus arteriosus. Type 3 patients most commonly presented with encephalocele and acquired hydrocephalus (11.45%), encephalocele and congenital hydrocephalus (5.09%), encephalocele and reduction deformity of the brain (3.74%), and encephalocele and atrial septal defect (3.38%). Chiari Type 4 patients most commonly had the following anomaly clusters: 15.95% reduction deformity of the brain with acquired hydrocephalus, 9.99% reduction deformity of the brain with congenital hydrocephalus, 6.73% atrial septal defect and reduction deformity of the brain, and 6.67% microcephalus and reduction deformity of the brain.

Conclusions: The top five body system anomalies in all Chiari malformation patients are nervous system, cardiac, genitourinary, neck and gastrointestinal anomalies. Chiari Types III and IV have higher congenital anomaly rates than Types I and II, especially for cardiac and nervous system anomalies.