Edward J. Gill
History of present illness
A 56-year-old postmenopausal woman, with a history of hypertension and Pelvic Organ Prolapse Quantification system (POP-Q) stage II pelvic organ prolapse with cystocele and stress urinary incontinence, underwent a tension-free vaginal tape midurethral sling (MUS), repair of cystocele, and post- operative cystoscopy one week ago. She now presents with the inability to empty her bladder for the last 16 hours. She has the urge to urinate but cannot empty well. She had been discharged home on the evening of surgery in good condition.
Since then, she was describes her urination as frequent, inter- mittent, and with a slow stream, and she described a feeling of not being able to empty her bladder completely. She has no back pain, and no nausea or vomiting. Her bowel function has been normal. She has no vaginal bleeding.
Physical examination
General appearance:Well-appearing woman in no distress Vital signs:
Temperature: 37.0°C Pulse: 88 beats/min
Blood pressure: 110/68 mmHg Respiratory rate: 14 breaths/min Oxygen saturation: 100% on room air BMI: 28 kg/m2
Back:No costovertebral angle (CVA) tenderness Abdomen:Soft, mildly tender over suprapubic area, no guarding or rebound
Pelvic:Normal external genitalia
Vagina:No discharge, nofluid leak, anterior wall incision difficult to visualize under urethra, but appears to be healing well without signs of infection. No mesh exposure
Imaging:Bedside bladder ultrasound scan shows a volume of 1200 cc
How would you manage this patient?
The patient has voiding dysfunction (VD) after recent MUS surgery for stress urinary incontinence. She is suffering from urethral obstruction from the recent surgery. A transurethral catheter was placed with the return of 1300 cc of clear urine with immediate relief of her symptoms. The urine analysis was normal. She was discharged home with the catheter on prophylactic nitrofurantoin and returned to the office in
seven days. The Foley catheter was discontinued after voiding trials in the office demonstrated marked improvement in bladder emptying with a post-void residual volume of 70 cc.
A follow-up visit at four weeks revealed normal voiding function and no urinary leakage.
Voiding dysfunction following midurethral sling surgery
Today, midurethral sling (MUS) surgery is the most common treatment in the world for stress urinary incontinence (SUI) and has reported success rates of 80–100%. It is performed through a small midline anterior vaginal wall incision and involves the placement of a small piece of polypropylene mesh under the midurethral. There are two main routes of MUS surgery (which refer to the route the arms of the slings take anatomically): the retropubic and trans-obturator. In both types, the sling rests in tissue tunnels created by introducer trocars specific for the procedure, and is not sutured in to place. If no operative report is available, they may be distin- guished at the bedside by the small exit incisions made at the time of surgery. These are small (<1 cm) incisions and are located on the lower abdomen just above the pubic bone approximately 6 cm apart and centered on the midline in the retropubic approach, and one on each side in the labio-crural folds in the trans-obturator approach. In addition, there is more recent version of“mini-slings,”which have no external excisions.
Voiding dysfunction (VD) after anti-incontinence surgery for stress urinary incontinence is a well-known complication.
Although MUSs have a lower incidence of VD than previous procedures like the Burch retropubic urethropexy, which is performed abdominally, and the more surgically involved pubovaginal slings, voiding difficulties still occur. The retropubic MUSs have a higher likelihood of VD than the trans-obturator slings [1]. VD describes problems with either bladder emptying or storage, or both. Lower urinary tract symptoms typically associated with storage problems include daytime urinary frequency, urgency, nocturia, and overactive bladder syndrome. Symptoms of problems with emptying include slow stream, hesitancy, intermittency, straining to void, spraying of the stream, and either incomplete emptying or complete inability to empty. These problems with storage and emptying can further be divided into arising from the bladder or from the outlet. It is useful to approach any prob- lems with VD by considering these etiologies.
Acute Care and Emergency Gynecology, ed. David Chelmow, Christine R. Isaacs and Ashley Carroll. Published by Cambridge University Press.
© Cambridge University Press 2015.
This patient has difficulty with emptying. This can result from a hypoactive or acontractile detrusor muscle of the bladder or from obstruction at the bladder outlet. In this patient, who is in the recent postoperative period, the etiology is likely outlet obstruction from the MUS. Other postopera- tive causes of obstruction after MUS surgery include post- operative edema, hematoma, or infection with abscess.
Cystitis can mimic many of these symptoms and must be considered in this patient. Cystitis is relatively common after MUS surgery occurring in up to 12.7% of patients [2].
Delayed return of voiding from a transient neuropathy can occur after any pelvic surgery including MUS surgery, hys- terectomy, or surgery for pelvic organ prolapse (POP). This usually resolves within several months. Decreased urine pro- duction in the postoperative period is less likely but possible, and can result from hypovolemia, occult blood loss, or from failure to restart a diuretic medication that had been used preoperatively.
The evaluation of postoperative VD after MUS begins with a thorough history and physical examination. This should include inquiry into fluid intake, fever, abdominal and/or back pain, medication use, especially hypertension medications and diuretics that could affect renal function.
In addition, it is important to note any preoperative problems with VD or history of urinary tract infections (UTIs). An operative report from the recent surgery also provides valu- able information as it will document which type of MUS was performed. Physical examination should include a thorough abdominal and pelvic examination including assessment of costovertebral angle tenderness. Vaginal examination should assess wound healing including signs of infection or hema- toma formation, a check for mesh exposure or extrusion, and examination for urine pooling in vagina. Overcorrection of the urethrovesical angle with kinking of the urethra may or may not be apparent on vaginal inspection. A urine analysis should be obtained and UTI ruled out. Bladder volume should be assessed by bedside ultrasound/bladder scan if available or by transurethral catheterization. Most adults feel the normal urge to void at a bladder volume of approximately 250–300 cm2. A bladder volume of more than 500 cm2 often causes extreme urgency and discomfort. Most adults empty almost all the bladder volume with voiding and a post-void residual greater than 50–100 cm2 may be pathologic, although there is no clearly defined volume in the literature at which a diagnosis of urinary retention can be made. Large bladder volume requires immediate drainage to relieve symp- toms, prevent neuropraxis type injury with resultant neur- opathy, and protect the upper urinary tract from the effects of prolonged increased pressure. Further evaluation with uro- dynamic testing and cystourethroscopy may be indicated for those patients when the diagnosis is unclear or for those who fail to respond to conservative treatment measures. Referal to
an Urogynecologist or Urologist with expertise in manage- ment of sling complications is advised.
After a presumptive diagnosis of VD after MUS from outlet obstruction has been made, the immediate treatment is for catheter drainage of the bladder. This may be accomplished with clean intermittent self-catheterization by the patient or a trained assistant. This may be useful in a motivated patient with less severe obstruction and dysfunction. Many patients in this situation, however, will require an indwelling transure- thral catheter. The length of catheterization is variable and controversial, but many surgeons will leave the catheter in place and recheck in a week. Patients with indwelling catheters may benefit from low-dose antibiotic prophylaxis with nitro- furantoin or trimethoprim.
Some of the causes of VD after MUS surgery like post- operative edema will resolve with time; however, physical obstruction from the sling may require further surgery to relieve the obstruction. Some experts feel that urinary reten- tion that persists greater than one week requires surgical release of the sling, whereas others will not surgically intervene until the patient has been catheter dependent for greater than four weeks. The argument for earlier intervention is a concern for irreversible bladder dysfunction that may occur with pro- longed bladder outlet obstruction. Further surgery is required for VD in 1.3–3.0% of patients [3,4]. Jonsson and colleagues recently reported the largest series to date, involving over 188 000 women from 2001 to 2010, and showed a 1.3% rate of reoperation for urinary retention [5]. Surgical interventions include early release of tension on the sling by downward traction, incision of the sling to release tension, urethrolysis, or removal of part or all of the sling.
Key teaching points
Midurethral sling (MUS) surgery is the most common surgical treatment for stress urinary incontinence in females.
Voiding dysfunction (VD) is a well-known complication of surgery for urinary incontinence. It is less common with the current use of MUSs, but it can still occur.
Any complaint consistent with VD after surgery for urinary incontinence should prompt an evaluation for residual bladder volume with either bedside ultrasound if available, or by transurethral catheterization.
Large residual bladder volumes and/or the inability to urinate require catheter drainage of the bladder to prevent neuropathy of the bladder and to protect the upper tract from the effects of prolonged increased pressure.
VD after MUS surgery will often resolve with bladder drainage, but requires close follow-up with a physician with expertise in the complications of incontinence surgery.
Case 87: Urinary retention following urethral sling surgery
References
1. Ogah J, Cody DJ, Rogerson L.
Minimally invasive synthetic suburethral sling operations for stress urinary incontinence in women: A short version Cochrane review.Neurourol Urodyn2011;30:
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2. Barber MD, Gustillo-Ashby AM, Chen CC, et al. Perioperative complications and adverse events of the MONARCH
transobturator tape, compared with the tension free vaginal tape.Am J Obstet Gynecol2006;195:1820–5.
3. Nguyen JN, Jakus-Waldman SM, Walter AJ, et al. Perioperative complications and reoperations after incontinence and prolapse surgeries using prosthetic implants.Obstet Gynecol2012;119:539–46.
4. Brubaker L, Norton PA, Albo ME, et al. Adverse events over two
years after retropubic or transobturator midurethral sling surgery: Findings from the Trial of Midurethral Slings (TOMUS) study.
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5. Jonsson Funk M, Siddiqui NY, Pate V, et al. Sling revision/removal for mesh erosion and urinary retention: Long- term risk and predictors.Am J Obstet Gynecol2013;2089(1):73 e1–7.