Urodynamic Investigation of the Storage and Voiding Phases in Women

Educational Objectives

The goal of this program is to improve the diagnosis and treatment of urodynamic dysfunction in women. After hearing and assimilating this program, the clinician will be better able to:

1. Select appropriate urodynamic studies for patients with urinary dysfunction.
2. Use the 9 Cs to interpret the findings of a urodynamic study.

Summary

Urodynamics: study of transport, storage, and evacuation of urine; tests include postvoid residual (PVR) test, uroflow­metry, electromyography (EMG), cystometry, and pressure-flow study

Clinical use of urodynamic studies: perform least expensive and least invasive test most likely to answer clinical question; illustrative case 1 — woman presents with persistent incontinence after insertion of midurethral sling; uroflowmetry and PVR urine test initially performed; peak flow 48 mL/sec (indicates failure of operation); illustrative case 2 — uroflometry reveals peak flow 5 mL/sec in male patient; findings suggest obstruction or poor contractility; appropriate questions before study — What is causing patient’s symptoms? unhelpful; Does this patient have stress incontinence? and Does this patient have detrusor overactivity? can be answered using urodynamic tests (What is best treatment for this patient? cannot); What is cause of this patient’s urinary retention? and Is upper urinary tract at risk? can be answered by testing; appropriate questions after sling procedure include Is patient obstructed? and Does patient have recurrent stress incontinence?; urodynamic study customized based on question

Principles of urodynamic testing: tests constitute only one part of clinical evaluation (other parts history and physical examination); reproducing patient’s symptoms during urodynamic testing desirable; abnormalities that do not correlate with patient’s symptoms may not be clinically meaningful; failure to record abnormality indicates failure of test and does not exclude abnormality; prevalence of artifacts on tracing high

9 Cs of urodynamic testing: complete study addresses all 9 Cs; pressure-flow urodynamic study includes 2 phases (filling and voiding); commencement of voiding marks end of filling phase and beginning of emptying (voiding) phase

Filling phase: includes 5 Cs; pressures recorded include vesical (Pves), abdominal (Pabdomen), rectal (Prectum), and detrusor (Pdet [Pabdomen minus Pves]); EMG, flow, and volume of filling also recorded

Involuntary detrusor Contraction: indicates detrusor overactivity; neurogenic overactivity distinguished from idiopathic overactivity by presence of relevant neurologic lesion; minimum amplitude defining involuntary detrusor contraction not determined; involuntary detrusor contraction absent in 20% to 40% of patients with urgency urinary incontinence; provocative maneuvers reduce incidence of false-negative results

Compliance; normal filling of bladder does not cause increase in pressure; change in volume divided by change in pressure; normal range 12 to 20 mL/cm H2O; measured from start of filling to point of voluntary or involuntary detrusor contraction; used to assess risk for deterioration of function of upper urinary tract; primary causes of abnormal compliance neurogenic bladder, radical pelvic surgery, spina bifida, irradiation, bladder outlet obstruction, and tuberculosis; patient presenting with stress incontinence after radical hysterectomy — operation often results in neurogenic bladder; in filling phase, change in volume 268 mL; increase in pressure 51 cm H2O; calculated compliance ≈5 mL/cm H2O; implantation of sling would risk development of renal failure

Continence: ability of sphincter muscles to withstand increase in abdominal pressure; leak point pressure — measured by Pves or Pabdomen during voluntary maneuvers (eg, straining, coughing); recorded as change in pressure or absolute pressure; detrusor leak point pressure — measure of passive pressure of bladder sufficient to overcome sphincter (overflow incontinence); applicable in patients with neurogenic incontinence; >40 cm H2O signifies high risk for dysfunction in upper urinary tract

Capacity: normal maximal cystometric volume 340 to 570 mL; cystometric capacity lower than functional capacity

Coarse sensation: first sensation of filling (normally at 170 to 200 mL) at less than maximal capacity; wish to void normally begins at ≈75% maximal capacity (<250 mL); strong wish to void, at <90% maximal capacity; recording of coarse sensation (eg, urgency, pain) not significant if symptom present only during testing

Voiding phase: Contractility — measure of strength and duration of bladder contraction sufficient to empty bladder; in women, normal contractility not defined; Clinical outlet obstruction — relationship between detrusor pressure and flow; bladder outlet obstruction poorly understood in women (nomograms not reliable); Coordination of sphincters — normally, contraction of bladder and opening of outlet synchronized to achieve micturition; detrusor external sphincter dyssynergia defined as rise in Pves with absence of flow; values during EMG normally increase as bladder fills; relaxation of external sphincter first step in micturition; bladder subsequently contracts; on completion of voiding, external sphincter closes; involuntary detrusor contraction normally causes rise in values during EMG to maintain continence; Complete emptying — normal PVR level not defined quantitatively; abnormal level PVR >0 that causes symptoms or damage to upper urinary tract; elevated PVR volume may be caused by obstruction or failure of bladder to contract; pressure-flow study recommended to determine cause

Readings

Gulpinar O et al: Overcoming the challenges of characterizing normal urodynamic parameters in middle-aged and older women. Can J Urol 2014 Aug;21(4):7358-64; Nitti VW: Pressure flow urodynamic studies: the gold standard for diagnosing bladder outlet obstruction. Rev Urol 2005;7(Suppl 6):S14-21; Rosier PF et al: International Continence Society good urodynamic practices and terms 2016: urodynamics, uroflowmetry, cystometry, and pressure-flow study. Neurourol Urodyn 2017 Jun;36(5):1243-60; Rosier PF et al: Do patients with symptoms and signs of lower urinary tract dysfunction need a urodynamic diagnosis? ICI-RS 2013. Neurourol Urodyn 2014 Jun; 33(5):581-6; Schurch B et al: Urodynamics in patients with spinal cord injury: A clinical review and best practice paper by a working group of The International Continence Society Urodynamics Committee. Neurourol Urodyn 2017 Aug 1; [Epub ahead of print]; Serati M et al: Urinary symptoms and urodynamic findings in women with pelvic organ prolapse: is there a correlation? Results of an artificial neural network analysis. Eur Urol 2011 Aug; 60(2):253-60.

Disclosures

For this program, the following has been disclosed: Dr. Rovner is an investigator and consultant for Allergen. The planning committee reported nothing to disclose.

Acknowledgements

Dr. Rovner was recorded at the 23rd Annual Rodney Appell Memorial Update in Gynecologic Urology Conference, presented by the University of Chicago Pritzker School of Medicine and NorthShore University HealthSystem and held February 8-10, 2018, on Providenciales, Turks and Caicos. For information on next year’s Annual Rodney Appell Memorial Update in Gynecologic Urology Conference, please visit urogynecologycourses.com. The Audio Digest Foundation thanks the speakers and sponsors for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0 CE contact hours.

Lecture ID:

UR410802

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.