The treatment of micturition problems in many patients with spinal cord injuries (SCI) can be facilitated by the development of methods that will characterize the functional contribution of detrusor contractility and the facilitation of the outlet to allow the free flow of urine. In these patients contributory factors can be a large prostate particularly when associated with neuromuscular dysfunction such as dyssynergia.  In this context we consider that the compliance of the prostate constitutes an important parameter facilitating flow because of its ability to dilate.  To this end we have developed a way to evaluate changes in the compliance of the prostate. This can be made during voiding using ultrasound images obtained during routine diagnostic urodynamic evaluations. 

 

Methods

A total of 36 consecutive SCI patients were evaluated with urodynamic studies and only the 9 patients who were capable of initiating micturition either voluntarily or by crede were included in the present study.  The principle of this approach is based on the measurement of urethral diameter, at the mid point of the urethra, Ddetmax, at the time of maximum. bladder pressure during voiding, Pdetmax, and at the 50% point, Pdet50, of the increasing bladder pressure, Ddet50.  These measurements were taken during urodynamic studies when ultrasound images of the prostate and urethra were obtained simultaneously with measurement of bladder pressure using a Hitachi ultrasound system with a linear array rectal probe interfaced to a Laborie Aquarius urodynamic system.  Ultrasound images, digitized and indexed with urodynamic data, were archived on disk for offline analysis using NIH Image software.  From sequences of 2D ultrasound images, defining the shape of the prostate and bladder neck during micturition, computer enhancement of the bladder/prostate/urethral interface was made to facilitate accurate measurement of the outline of the urethra.  From these measurements of pressure and pTampere Hall, Tampere, Finland • 28 – 31 August, 2000

 

Results
The table shows the values of direct mesurements of pressure and diameter made on the basis of the urodynamic and digitized ultrasound visualizations, in a total of 9 SCI patients.

 

Urethral Diameter
mm Detrusor Pressure

cmH2O Relative Stiffness Ddet50DdetmaxPdetmaxPdet50ÅHvation suggests that there are regional differences in the compliance of the prostate.  In view of the possibility of regional variations in prostatic compliance, it is speculated that the identification of the contribution of these regions to micturition can provide useful information regarding pharmacological or surgical treatment.  Furthermore important questions such as the effectiveness of alpha blockers in modulating the compliance of the prostate can be addressed using this approach.