SUFU 2019: Challenges Defining “Normal” In Multi-Channel Urodynamics

Miami, FL ( Multi-channel urodynamics is widely used to evaluate the storage and voiding functions of the lower urinary tract. However, as many urologists will attest, the study is “invasive, non-physiologic, and prone to artifacts,” as reported by Natalie Swavely, MD, of Virginia Commonwealth University. Consequently, there are challenges regarding both the interpretation and clinical utility of urodynamics. Prior studies, for instance, have shown poor repeatability of urodynamic findings in short-term follow-up in healthy volunteers, as well as inconsistent demonstrations of detrusor overactivity in men with and without lower urinary tract symptoms.

In a podium session at the 2019 SUFU Winter Meeting, Dr. Swavely sought to examine urodynamics results in normal, healthy volunteers to better define what constitutes as “normal.” Such findings could, therefore, be used to evaluate novel adjuncts or alternatives to standard urodynamics.

Her group recruited 24 healthy volunteers (10 men and 14 women) to undergo standard multi-channel urodynamic testing. Eligibility was dependent on having ≤1 on all symptom questions of the ICIq-OAB survey and having no history of medical conditions or use of medications that affect bladder function. All participants were also required to complete a three-day bladder diary and undergo evaluation with uroflowmetry and bladder scans. Urodynamics was performed according to ICS standards, and all tracings were evaluated twice by an expert neuro-urologist in a blinded fashion. Urodynamics data was analyzed categorically for compliance, detrusor overactivity, bladder outlet obstruction, contractility, usage of straining during voiding, detrusor contraction, EMG activity, and flow.

The mean age, BMI, and maximum voids were comparable across sex, as were ICIq-OAB scores for frequency, nocturia, urgency, and urge incontinence. All participants had at least 1 urodynamic abnormality with an average of 4.25±1.29 abnormalities per participant. The most common abnormalities included uncoordinated EMG activity (87.50%), straining to void (79.17%), intermittent flow (70.83%), and poorly sustained bladder contraction (60.87%).

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Based on their findings, the authors reported that normal, healthy volunteers have high rates of abnormal urodynamic findings, despite being completely asymptomatic. They, therefore, concluded that artifacts and the non-physiologic nature of urodynamic testing present serious challenges in both diagnostic interpretation and clinical utility of urodynamics and that there is a need to develop less-invasive and more physiologic techniques to more accurately evaluate bladder function.

Presented by: Natalie Swavely, MD, VCU Division of Urology, VCU Health

Written by: Judy Choi, MD, Assistant Professor, Department of Urology, University of California, Irvine @judymchoi