Tethered cord syndrome in the United States: Cluster analysis of presenting anomalies and associated conditions

Purpose: Tethered cord syndrome (TCS) is an occult spinal dysraphism that includes low lying conus, tight filum terminale, lipomeningomyelocele, split cord malformations, dermal sinus tracts, and dermoids. This congenital disorder has been associated with musculoskeletal, neurological, and gastrointestinal abnormalities. This study presents a retrospective review of the prospectively collected data of TCS patients and their concurrent diagnoses or associated anomalies. Methods: The National Inpatient Sample (NIS) database from 2003 to 2012 was used for data collection. Hospital-and year-adjusted weights allowed for accurate assessment of the incidence of TCS, as well as cardiac and gastrointestinal (GI) and genitourinary (GU) anomalies. K-means clustering analysis was run to discover patterns of concurrent cardiac, GI, GU, and other system anomalies in TCS patients. Results: A total of 13,470 discharges with a diagnosis of TCS were identified in the NIS database, and at least one additional anomaly was identified in 40.7% of TCS patients. The most common secondary anomalies by system were: spine (24.48%), cardiac (6.27%), and urinary (5.37%). For patients with multiple anomalies, the most common combinations were GI and cardiac (4.55%), urinary and GI (4.26%), and urinary and cardiac (4.19%). The most common spinal association was spina bifida (13.65%). The most common neurological or musculoskeletal anomaly was any VACTERL association (13.45%). The top relation in GI and GU anomalies was cervix and female genitalia anomalies (69.1%). The most common specific anomalies were spina bifida, large intestine atresia, Rubenstein-Taybi syndrome, and atrial and ventral septal defects. Conclusion: This study provides a nationwide prospective on congenital anomalies and concurrent conditions present in tethered cord syndrome patients in the United States and demonstrates that 40.7% of TCS patients have at least one associated anomaly. The most common congenital anomalies studied were spina bifida, urogenital with or without cardiac septal defects, and cystourethral anomaly or cystic kidney disease with or without large intestinal atresia.