Preoperative urinary tract obstruction in scoliosis patients

Background While the association between scoliosis and impairments in cardiac and respiratory function has been well characterized in clinical practice and research, the potential effect of scoliosis on urinary tract structure and renal function has received little attention. Therefore, the purpose of our study was to evaluate the preoperative clinical characteristics of urinary tract structure and renal function in pediatric patients with idiopathic scoliosis, using a combination of blood tests, urinalyses, and imaging procedures. Methods Preoperative measures of urinary tract structure and renal function were obtained for 16 patients, 13 to 17 years old, scheduled for corrective surgery for idiopathic scoliosis. Preoperative assessment included blood test and urinalyses, combined with structural imaging by ultrasound (US), magnetic resonance (MRI), magnetic resonance urography (MRU), and radioisotope tracing (RI), using technetium-99mTC-mercaptoacetyltriglycine (99mTC-MAG3). Differences in blood and urine tests between patients with and without urinary tract obstruction (UTO) were evaluated for significance using Mann-Whitney U test. Results For all 16 patients, blood tests and MRU results were within normal limits. Evidence of dilatation of the renal pelvis was identified by US imaging in 8 (50.0%) patients. UTO was identified by RI in 6 (37.5%) patients. UTO was associated with elevated levels of β2-microglobulin concentration. A urinary β2-microglobulin concentration above 0.7μg/mg Cr differentiated patients with UTO, from those without UTO, with a sensitivity of 100% and specificity of 70%. Conclusions β2-microglobulin concentration may provide a useful marker to screen for asymptomatic UTO in patients with idiopathic scoliosis. This article is protected by copyright. All rights reserved.