Validation of A Wireless Telemetric Bladder Pressure Monitoring System in Traumatic Thoracic Spinal Cord Injury in Yucatan Minipigs

Neurogenic lower urinary tract dysfunction (NLUTD) is a major cause of morbidity and reduced quality of life after spinal cord injury (SCI). In pre-clinical research, small and large animal models such as rats, dogs, and minipigs have been used to investigate NLUTD through urodynamic studies (UDS) such as conventional filling cystometry. Although filling cystometry is currently considered the gold standard for bladder monitoring in pre-clinical research, this approach has several well-recognized limitations. The aim of this study was to develop and evaluate the feasibility of an implantable, radiotelemetric system for monitoring bladder pressure in a Yucatan minipig model of SCI. The transmitter was surgically implanted in the dome of the bladder and several UDS experiments were conducted to evaluate the system's effectiveness at measuring pressure compared to conventional UDS equipment. We observed a strong correlation and agreement between the transmural telemetry sensor and the UDS system. There was no significant difference between bladder compliance and baseline bladder pressure between the two sensor systems. However, the telemetry system recorded significantly lower voiding and non-voiding contraction pressure amplitudes as well as lower voiding threshold pressures and detrusor after-contraction measured with the telemetry system. The telemetry system appeared to be a reliable and accurate method for assessing bladder pressure and allowed for an evaluation of urodynamics in a pig model of SCI for several months. The application of this method could enable a more detailed in vivo evaluation of NLUTD after SCI and a better understanding of micturition behavior during natural-filling, ambulatory urodynamics.