Evaluation of Novel Technique for Studying Ureteral Functionin Vivo

Abstract

Knowledge of the ureteral response to instrumentation is limited. Ureterodynamic parameters such as intraureteral pressure, conduction velocity, direction of peristalsis, and electromyography have been measured using a variety of methods; however, these techniques are impractical for routine clinical use. The aim of this study was to evaluate a new commercial ureteral pressure transducer catheter, which records peristaltic frequency, conduction velocity, and intraureteral pressure. This device was assessed in an animal model and in patients who had undergone ureteroscopy. An ambulatory urodynamic monitoring system was adapted to record the output from two pressure transducers mounted on a 4F ureteral catheter, which was inserted into the left ureters of six anesthetized pigs to record peristalsis. In six patients who had undergone ureteroscopy with or without stone removal, the recording catheter was inserted at the end of the procedure, and recovery of peristalsis was monitored for as long as 24 hours. The un-instrumented pig ureter showed spontaneous peristalsis immediately on catheter insertion, whereas the instrumented human ureter displayed a variable response that appeared to be related to previous physical or pharmacologic effects. Peristaltic frequency, pressure, and conduction velocity can be measured with the ureteral catheter described in both the experimental and clinical settings. Within the first 24 hours after ureteroscopy, peristaltic recovery is variable. Such information may enable both elucidation of the underlying mechanisms and improvement in the treatment of a variety of upper urinary-tract disorders.