Re: Slack M. Culligan P, Tracey M, Hunsicker K, Patel B, Sumeray M. 2004. Relationship of urethral retro-resistance pressure to urodynamic measurements and incontinence severity.

AIMS The urethral retro-resistance pressure (URP) is a retrograde urethral pressure profile measured by a new urodynamic measurement system.1GYNECARE MoniTorr Urodynamic Measurement System (ETHICON, Inc., Somerville, NJ). URP is the pressure required to achieve and maintain an open sphincter. This clinical investigation focused on a comparison of URP to standard urodynamic measurements and an examination of their relationship to incontinence severity. METHODS Twenty-two centers enrolled 258 stress incontinent women in a randomized, crossover study of two groups: (1) test procedure followed by multichannel urodynamics, (2) multichannel urodynamics followed by test procedure. We defined incontinence severity categories using 24 hr urine loss and assessed these categories using incontinence quality of life (I-QOL), urinary incontinence severity score (UISS), incontinence visual analogue score (VAS), URP, maximum urethral closure pressure (MUCP), and leak point pressure (LPP). RESULTS The mean age was 56.2 (+/-12) years. No order effect was present. The correlation coefficient between URP and MUCP was 0.31 (95% CI 0.19-1, P < 0.0001); between URP and LPP was 0.28 (95% CI 0.12-1, P = 0.003); and between MUCP and LPP was 0.14 (95% CI-0.04-1, P = 0.101). The mean values for URP across symptom severity categories were significantly different (P = 0.028) and decreased with increasing severity. The mean values for MUCP and LPP did not decrease with increasing severity. CONCLUSIONS The study demonstrated that URP had a consistent relationship with incontinence severity. The data suggested that URP is a physiological measure of urethral function and may have clinical utility as a diagnostic tool. Future outcomes-based research is necessary to establish the predictive value of URP, MUCP, and LPP measurements in terms of incontinence cure rates and diagnosis of sphincter dysfunction.