Neuromuscular Characterization of the Urethra in Continent Women

Abstract

Objectives To describe quantitative urethral function parameters in a racially diverse group of continent women. Materials and Methods Following Institutional Review Board approval, we recruited women without urinary incontinence from the community. To be considered continent, participants answered “never” to the first six questions on the stress subscale of the Medical, Epidemiologic, and Social Aspects of Aging urinary incontinence (MESA) questionnaire. Participants all underwent quantitative concentric urethral electromyography (EMG) and urodynamic testing (UDS). Results Thirty-one women with a mean±SD age of 39±14 years underwent EMG and UDS. The cohort was racially diverse with 13 Caucasians (43%), 13 African Americans (43%), and 4 Hispanics (14%). Body mass index (BMI) (P=.12, .06), age (P=.40, .64), and vaginal parity (P=.53, .76) did not differ by race or ethnicity. We did not detect differences in any EMG parameter by race, ethnicity or vaginally parity. A mean (range) of 30 motor unit action potential analysis (MUP) (10-55) were identified and analyzed in Multi-MUP analysis and 14 (8-21) were identified and analyzed in IP analysis. On average, 37±20% MUPs were polyphasic. Age significantly correlated with several measures of urethral sphincter function. Increasing age was inversely correlated with interference analysis (IP) turns (−.57, p=.001), IP amplitude (r=−.43, p=.02), IP turns/amplitude (r=−.54, p=.003), maximum urethral closure pressures (MUCP) (r=−.41, p=.04). Similarly, MUCP correlated with IP amplitude (r=.38, p=.04). Conclusions This urethral neuromuscular function data on the largest cohort of continent women fully characterized with quantitative urethral EMG demonstrates significant neuropathic MUP changes with advancing age.

Quantitative EMG of external urethral sphincter in neurologically healthy men with prostate pathology

“…Although urethral sphincter normative values obtained using quantitative EMG in men are still lacking, Kenton and collaborators recently used an automatic EMG analysis to describe urethral neuromuscular function in a cohort of continent women, providing female EUS normative data. Furthermore, Podnar and co‐workers, using a standardized technique, provided normative data for MUP and IP parameters of the EAS from a large group of healthy subjects.…”

“…. Moreover, urethral sphincter normative values recorded in a group of continent women using quantitative EMG have been reported recently in a single study . In contrast, reference parameters obtained from a large group of normal men have not been reported …”

Continent women have better urethral neuromuscular function than those with stress incontinence

“…Stress incontinence patients seeking care at Loyola University’s Urogynecology Center were recruited if they had at least one answer of “sometimes” or “always” on first six items on the Medical, Epidemiologic, and Social Aspects of Aging urinary incontinence questionnaire [11]. In addition, asymptomatic control women without urinary incontinence were recruited from the community using flyers and webbased advertisements and have been previously described [12]. We excluded women with a history of neuromuscular disease, prior continence surgery, or coagulaopathy; who had stage III or IV pelvic organ prolapse; who were less than 6 months from their most recent vaginal delivery; who were taking an anticoagulant mediation; and who had an elevated post-void residual urine volume or urine dipstick positive for nitrites or leukocytes.…”

Medication Effects on Periurethral Sensation and Urethral Sphincter Activity

“…However, previous work by Dr. Kenton showed no racial differences in urodynamic or CNE parameters in a similar, but more racially balanced, population of healthy controls (23). Strengths of this pilot study include random and blinded allocation to groups and our prospective, controlled collection of urethral EMG and CPT data in an asymptomatic population of women.…”