Prevalence of Abnormal Urodynamic Study Results in Patients with Congenital and Idiopathic Scoliosis and Its Predictive Value for the Diagnosis of Tethered Cord Syndrome: A Single Institution Clinical Study

STUDY DESIGN: A total of 110 patients with scoliosis were enrolled in this analytical cross-sectional study. PURPOSE: We aimed to compare the urodynamic study (UDS) results of patients with idiopathic scoliosis (ISC) and congenital scoliosis (CSC) and to evaluate the clinical significance of abnormal UDS findings in predicting underlying tethered cord syndrome (TCS). OVERVIEW OF LITERATURE: An abnormal UDS finding is commonly found in patients with CSC. However, there is no consensus regarding its prevalence in patients with ISC. METHODS: Using the STROBE checklist for cross-sectional studies, 110 patients with scoliosis were selected based on our inclusion and exclusion criteria. Among the patients, 76 presented with ISC and 34 with CSC. Demographic data and other details, such as the results of spine radiography, UDS, and magnetic resonance imaging of the spine in both supine and prone positions, were recorded and analyzed. RESULTS: Approximately 50% of patients with CSC had normal UDS findings; 8.8%, mild impairment; and 41.2%, significant abnormalities. Moreover, 67.1% of patients with ISC had normal UDS findings; 9.2%, mild impairment; and 23.7%, significant abnormalities (p =0.166). TCS was identified in 38.2% and 26.3% of patients with CSC and ISC, respectively (p =0.571). In patients with ISC, a significantly abnormal UDS finding indicated that the risk of TCS increased from 26.3% to 50% (odds ratio [OR], 4.2; p =0.009). Meanwhile, in patients with CSC, the risk was almost similar (OR, 0.8; p =0.8). CONCLUSIONS: Even with the absence of subjective urinary symptoms, subclinical urologic impairments can be observed in a significant number of patients with ISC. An abnormal UDS finding can be a sign of underlying spinal cord tethering in a patient with ISC who is a candidate for corrective spine surgery even though it is an independent variant and is not exclusive to candidates for surgery. This finding has high clinical utility for neuro- and ortho-spine surgeons who aim to correct scoliosis (OR, 4.2; p =0.009).