Artificial Urinary Sphincter Placement Workup

Updated: Nov 29, 2021
  • Author: Kamran P Sajadi, MD; Chief Editor: Edward David Kim, MD, FACS  more...
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Laboratory Studies

Urinalysis and urine culture

The possibility of UTI should be ruled out before implanting an artificial urinary sphincter. The presence of a UTI is a contraindication to artificial urinary sphincter placement.

Serum white blood cell (WBC) count

Systemic leukocytosis should be treated before surgery.

Serum creatinine

The patient should have relatively normal and stable renal function before AMS 800 artificial urinary sphincter placement.


Imaging Studies

Voiding cystourethrography

This test is optional but can be used to assess bladder neck and urethral function (ie, internal, external sphincter) during the filling and voiding phases.

Voiding cystourethrography (VCUG) allows radiographic observation of an incompetent bladder neck and coincident leakage during Valsalva maneuvers. VCUG is performed most often at the time of videourodynamics.

Grade 2 or higher vesicoureteral reflux on VCUG should be corrected before placement of the artificial urinary sphincter because the sphincter can exacerbate reflux.


Other Tests

Voiding diary

A voiding diary is a daily record of a patient's bladder activity. The diary is an objective documentation of a patient's voiding pattern, incontinent episodes, and any inciting events associated with urinary incontinence. Although not critical, a properly logged voiding diary can provide stronger documentation of the degree of incontinence than the standard question regarding number of pads per day used by the patient. Keeping track of fluid intake and urine output in the diary can give further insight into the patient's incontinence and identify patients who can improve their incontinence with less invasive interventions, such as timed voiding. It can also help identify patients with associated problems such as polyuria.

Physical examination

All patients with incontinence should undergo a complete physical examination. Women with incontinence must undergo a full pelvic examination to note pelvic floor weakness (eg, cystocele, rectocele, enterocele), urethral hypermobility, urethral or vaginal lesions, or uterine or adnexal masses.

Pad test

Patients with classic intrinsic sphincteric dysfunction present to the office with a diaper or a pad in place. An adult male with a damp or wet pad inside his underwear has urinary incontinence unless proven otherwise. It is important to ask patients not only how many pads they use in a day but also how wet those pads get (from lightly dampened to soaked).

Standing cough stress test

The patient stands upright with feet shoulder width apart. Place a large towel under the patient's feet or a small trash can between the patient's feet to catch the flow of urine. Instruct the patient to perform the Valsalva maneuver and to cough in gradients (ie, mild, moderate, severe). Observable urine leakage in this position constitutes a positive test result. If the bladder is empty at the time of the Valsalva maneuver or cough, the test result is falsely negative. An excellent alternative is to leave the bladder full following cystoscopy and have the patient stand over a towel. Ask the patient to perform the Valsalva maneuver, and watch for a leak. Following this task, see if the patient can maintain continence while walking to the restroom.

Urodynamic studies

Urodynamics is a means of evaluating the bladder capacity, compliance, abdominal leak point pressure, presence of phasic contractions, and pressure-flow relationship between the bladder and the urethra.

Simple urodynamics involves noninvasive uroflow, postvoid residual (PVR) urine volume, and single-channel cystometrography (CMG). A single-channel CMG (simple CMG) is used to assess the first sensation of filling, fullness, and urge. Bladder compliance and the presence of uninhibited detrusor contractions (eg, phasic contractions) can be noted during this filling CMG.

  • A filling CMG is used to assess the bladder capacity, compliance, and presence of phasic contractions.

  • Most commonly, liquid filling medium is used.

  • An average adult bladder holds approximately 450-500 mL of urine.

  • During the test, provocative maneuvers, such as coughing, handwashing, sitting on the commode for 1 full minute, and heel jouncing, may help unveil bladder instability.

  • Insert a catheter (connected to a special computer) into the bladder for a single-channel CMG. Information recorded by the computer is interpreted.

  • Eyeball cystometry does not require special computers. Perform bedside cystometry by inserting a catheter into the bladder, hanging the irrigant bag at a predetermined height (eg, 100 cm water), and observing the fluctuation of the meniscus within the water chamber during uninhibited detrusor contractions. Eyeball cystometry can also be performed with a flexible cystoscope being used as the connection tubing, allowing simultaneous cystoscopy.

Multichannel urodynamic studies are more complex than simple urodynamic studies and can be used to obtain additional information, including a noninvasive uroflow, PVR, filling CMG, abdominal or Valsalva leak point pressure (ALPP or VLPP), voiding CMG (pressure-flow study), and electromyography (EMG). Water is the fluid medium used for multichannel urodynamics.

  • A voiding CMG (pressure-flow study) simultaneously records the voiding detrusor pressure and the rate of urinary flow. This is the only test that can be used to assess bladder contractility and the extent of a bladder outlet obstruction. Pressure-flow studies can be combined with a voiding CMG and videourodynamic study for complicated cases of incontinence. Note that most adult men normally void with detrusor pressures (PdetQmax) of 40-80 cm water. However, pressures of 20-30 cm water or lower are considered to be within the reference range if uroflow (Qmax) is within the reference range or high.

  • Abdominal (Valsalva) leak point pressure (ALPP) measurements allow clinicians to classify stress urinary incontinence into type I, type II, and type III, or type II and III in combination. ALPP of 0-60 cm water is classified as type III stress urinary incontinence (ie, intrinsic sphincteric dysfunction). In short, the outlet is so weak that even low pressures can overcome the resistance and produce incontinence. ALPP of 60-90 cm water is classified as type II/III stress urinary incontinence (ie, combination of urethral hypermobility and intrinsic sphincteric dysfunction). ALPP of 90-120 cm water is classified as type II stress urinary incontinence (ie, urethral hypermobility). ALPP greater than 120 cm water is classified as type I stress urinary incontinence.

  • ALPP should be measured when the bladder is half full (eg, 250 mL), and both the Valsalva and coughing maneuvers should be performed. Initially, instruct the patient to bear down in gradients (ie, mild, moderate, severe) and then note the ALPP as the lowest intravesical pressure (Pves) at which leakage is observed.

  • If Valsalva maneuvers fail to produce the desired response, instruct the patient to cough in gradients (ie, mild, moderate, severe) to obtain the ALPP. The lowest intravesical pressure (Pves) at which leakage is observed is the ALPP. The ALPP obtained with the Valsalva maneuver is more accurate than the cough-induced ALPP. However, both techniques should be used if Valsalva maneuvers fail to manifest stress urinary incontinence.

  • Alternatively, both Valsalva and cough-induced ALPP may be repeated by increasing the bladder volume in 100-mL gradients. Increasing the bladder volume reportedly increases the sensitivity of detecting ALPP.

  • Obtaining ALPP in male stress incontinence (ISD) is optional because men with type III stress incontinence, by definition, have ALPP less than 60 cm water.

The most sophisticated study is videourodynamics, which is the leading standard in the evaluation of a patient with incontinence. In this study, the following are obtained: noninvasive uroflow, PVR, filling CMG, ALPP, voiding CMG (pressure-flow), EMG, static cystography, and VCUG. The fluid medium used for videourodynamics is radiographic contrast.

Performing urodynamic studies

  • Instruct the patient to arrive at the urodynamic laboratory with a relatively full bladder. Note that patients with ISD have a low-volume or empty bladder because of continuous incontinence. Perform a noninvasive uroflow and PVR.

  • Some physicians perform cystoscopy at the same time as urodynamics, although the two can be done separately. Place a urodynamic urethral catheter, rectal tube, and EMG electrodes.

  • Rotate the patient to a standing or sitting position and equalize transducers. Commence bladder filling using room-temperature water or contrast (Conray). Cold water may evoke false-positive detrusor contractions (phasic contractions). Fill the bladder at a medium rate (eg, 50 mL/min). Assess the first sensation of filling, fullness, and urge. Note bladder compliance and mark the presence of uninhibited detrusor contractions.

  • When the bladder fills to 250 mL, measure the ALPP. Instruct the patient to perform the Valsalva maneuver in gradients (ie, mild, moderate, severe) followed by cough (ie, mild, moderate, severe). Observe the urine leakage fluoroscopically and by direct inspection.

  • Following the ALPP measurements, finish the filling CMG to completion. When the patient has a strong desire to void, perform a voiding CMG (pressure-flow study). At this point, note urodynamic parameters, such as maximal flow rate (Qmax) and detrusor pressure at maximal flow rate (PdetQmax).

  • During the voiding CMG, note the activity of the EMG electrodes and VCUG for possible detrusor sphincter dyssynergia (DSD). The presence of DSD is confirmed by increases in EMG activity during detrusor contraction or closure of the external sphincter on VCUG during voiding.

  • After the patient voids to completion, the videourodynamic study is complete. The patient is informed about the findings on urodynamic studies and is sent home.

Uroflow rate

The uroflow rate is a screening test used mainly to evaluate bladder outlet obstruction. The uroflow rate is the volume of urine voided per unit of time. Maximal flow rate (Qmax) greater than 15 mL/s may be considered within the reference range. Low uroflow rates (< 15 mL/s) may reflect urethral obstruction, a weak detrusor, or both. This test alone cannot be used to distinguish between obstruction and a poorly functioning detrusor. Patients with intrinsic sphincteric dysfunction demonstrate uroflow rates within the reference range. A voided volume of 150 mL is a generally accepted minimum for accurate uroflowmetry, and variations of 2-4 mL/s in a single patient are common, so more than one measurement may be required. A maximum flow rate of less than 15 mL/s is usually considered abnormal but must be considered within the context of the patient's clinical presentation.

Postvoid residual urine volume

This measurement is a part of the basic evaluation for urinary incontinence. Healthy men usually have a PVR urine volume of less than 100 mL. If the PVR volume is high, the bladder may be atonic or the bladder outlet may be obstructed. Both of these conditions cause urinary retention and overflow incontinence. Patients with intrinsic sphincteric dysfunction have minimal PVR urine volume.


EMG helps ascertain the presence of coordinated or uncoordinated voiding. Failure of urethral relaxation during a bladder contraction results in uncoordinated voiding (ie, DSD). EMG is not necessary for evaluation of men who are incontinent after prostatectomy; however, EMG is used in combination with multichannel urodynamic studies and is important in the evaluation of neurogenic bladders.


Cystoscopy is optional in female patients. However, it may uncover bladder lesions (eg, stitch in the bladder, bladder cancer, bladder stone, vesicovaginal fistula) that, although uncommon, would remain undiagnosed based on urodynamics findings alone. The bladder can be left full following cystoscopy to perform the standing cough test.

In male urinary incontinence, cystoscopy should be performed more routinely, because a visual inspection of the urethra helps establish the presence of urethral stricture or diverticulum, bladder neck contracture or anastomotic stricture, or gross evidence of poor urethral coaptation and closure. It is important to examine the external sphincter both with and without the flow of irrigant to ascertain the degree of sphincter incompetence.

In general, cystoscopy is also indicated for patients reporting persistent dysuria, storage symptoms, or hematuria. Obvious causes of bladder overactivity, including cystitis, stone, and tumor, can be easily diagnosed. Patients with a history of pelvic radiation may have findings of radiation cystitis on cystoscopy. This information is important in determining the etiology of the incontinence and may influence treatment decisions.

In the absence of videourodynamics, the clinician may obtain adequate information regarding male incontinence from (1) noninvasive uroflow and PVR and (2) simple cystometry in combination with cystoscopy.