Lightning Podiums: Spinal Potpourri - 803B

Presented by: S. Horn

Author(s):

S. Horn(1), G. Poorman(1), D. Vasquez-Montes(1), C. Bortz(1), F. Segreto(1), L. Steinmetz(1), N. Stekas(1), R. de la Garza Ramos(1), D. Nikas(2), P. Passias(1)

(1) New York University Langone Orthopedic Hospital, Division of Spinal Surgery, New York, NY, United States
(2) University of Illinois Health System, Chicago, IL, United States

Abstract

Introduction: Tethered cord syndrome (TCS) is a form of an occult spinal dysraphism which include 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. The aim of this study was to utilize a nationwide database to study the TCS 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. NIS supplied hospital- and year-adjusted weights allowed for accurate assessment of 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, as well as other system anomalies in TCS patients. Cluster categories were created using as variables only the anomalies occurring >0.5% of sample population presenting anomalies (to remove confounders). Number of cluster categories (K) was adjusted to fit groups with high co-occurrence of frequent anomalies by creating several iterations of groupings until increase in K caused repeated significant drop/little gain in Sum of Square error within clusters. Different seed iterations were also created after ideal K was established to ensure major groups relationships were not missed by allowing for re-arrangement of data points. Remaining categorical variable "cluster" contained the most significant relationships within aforementioned anomalies.

Results: 13,470 patients were identified in NIS with a diagnosis of TCS. 5,488 (40.7%) of TCS patients have at least one additional anomaly. Secondary anomalies most frequently presented in the following systems: spine (24.48%), cardiac (6.27%), urinary (5.37%), GI (4.55%), nervous (3.16%), GU (2.48%), and bone (1.01%). 1,691 (12.55%) of TCS patients had more than one body system anomaly. Of patients with more than one associated anomaly, the most common combination of body system anomalies were GI and cardiac (4.55%), urinary and GI (4.26%), and urinary and cardiac (4.19%). The most common spinal associations were: 13.65% spina bifida, 0.39% Klippel-Feil, and 0.12% with torticollis. The most common neurological and musculoskeletal anomalies were: 13.45% with any VACTERL association, 3.58% with Rubenstein-Taybi syndrome, 0.42% with hydromyelia, 0.16% with chromosome 22 defect/deletion. 23.8% of TCS patients with microcephalus also had patent ductus arteriosus and 18.0% of TCS patients with reduction deformities of the brain presented with atrial septal defect. The top relations in GI/GU anomalies in TCS patients were: 69.1% of cervix/female genitalia anomalies and 68.7% of cystourethral anomalies presented with large intestine atresia; 37.9% of cystic kidney disease cases also presented with large intestine atresia. The most common specific anomalies were spina bifida, large intestine atresia, Rubenstein-Taybi syndrome, and atrial and ventral septal defects.

Conclusions: This study provides a nationwide prospective on congenital anomalies and concurrent conditions present in the tethered cord syndrome patient population in the United States. 40.7% of TCS patients have at least one associated anomaly reported. These associations' enroot to early gastrulation phase during embryogenesis. The most common congenital anomalies studied were spina bifida, urogenital with or without cardiac septal defects, cytourethral anomaly or cystic kidney disease with or without large intestinal atresia.