A balloon-tipped catheter for measuring urethral pressures

Abstract

Background: Better methods are needed for recording urethral function for complex urologic problems involving the bladder, urethra, and pelvic floor. Objective: To evaluate a balloon catheter for recording urethral pressure and function using bench-top testing and evaluation in an animal model. Methods: Balloon pressure-recording methods included slightly inflating the balloon with water and placing the pressure transducer on the distal end of the catheter. For bench-top testing, manual procedures and a silastic tube with a restriction were used. In 3 anesthetized dogs, pressure recorded from the skeletal urethral sphincter was induced with electrical stimulation of the sphincter. Anal sphincter pressure was also recorded. Results: Bench-top testing showed good pressure recordings, including a confined peak at the tube restriction. Animal tests showed urethral pressure records with rapid responses when electrical stimulation was applied. Peak pressure at the urethral skeletal sphincter was 55.7 ± 15 cmH2O, which was significantly higher than the peak pressure recorded 2 cm distally in the proximal urethra (3.3 ±2.3 cmH2O). Peak anal pressures were smaller and unchanged for the 2 stimulations. Conclusions: Balloon-pressure recordings showed rapid responses that were adequate for the tests conducted. In the animal model, high-pressure contractions specific to the skeletal urethral sphincter were shown. Balloon-tipped catheters warrant further investigation and may have applications for the evaluation of detrusor-sphincter dyssynergia after spinal cord injury or for stress urinary incontinence. © 2009 by the American Paraplegia Society.