Pelvic Floor Strengthening
Conservative management is a reasonable initial approach to most patients with urinary incontinence. The rationale behind conservative management is to strengthen the pelvic floor and provide a supportive “backboard” against which the urethra may close. For both SUI and urgency urinary incontinence, these fundamentals prove valuable. With SUI, pelvic floor strengthening attempts to compensate for anatomic defects. For urgency urinary incontinence, it intensifies pelvic floor muscle contractions to provide temporary continence during waves of bladder detrusor contraction. For strengthening, options include active pelvic floor exercises and passive electrical pelvic floor muscle stimulation.
Active pelvic floor muscle training (PFMT) may lessen, if not cure, urinary incontinence in women who have mild to moderate symptoms. Also known as Kegel exercises, PFMT entails voluntary contraction of the levator ani muscles. As with any muscle building, isometric or isotonic forms of exercise may be selected. Exercise sets are performed numerous times during the day, with some reporting up to 50 or 60 times each day. However, specific details in performance of these exercises are subject to provider preference and clinical setting.
If isotonic contractions are used for PFMT, a woman is asked to squeeze and hold contracted levator ani muscles. Women, however, often have difficulty isolating these muscles. Frequently, patients will erroneously contract their abdominal wall muscles rather than the levators. To help localize the correct group, an individual may be instructed to identify the muscles that are tightened when snug pants are pulled up and over her hips. Moreover, in an office setting, a provider can determine if the levator ani group is contracted by placing two fingers in the vagina while Kegel exercises are performed.
At our institution, we aim to help patients achieve a sustained pelvic floor contraction of 10 seconds. We begin with the contraction duration a patient can sustain (e.g., 3 seconds) and ask them to hold for this long and then relax for one to two times this duration (e.g., 6 seconds). This squeeze and release is repeated 10 to 15 times. Three sets are performed throughout the day for a total of approximately 45 contractions. Over a series of weeks with frequent follow-up visits, the contraction duration is steadily increased. Patients thus improve the tone of their pelvic floor muscles and are usually able to more forcefully squeeze their muscles in anticipation of sudden increases of intraadominal pressure for SUI.
Alternatively, if isometric contractions are used for PFMT, a woman is asked to rapidly contract and relax the levator ani muscles. These “quick flicks” may prove advantageous if waves of urinary urgency strike. Of note, there is no value to stopping urination midstream, and women are counseled that this practice often worsens voiding dysfunction.
To augment exercise efficacy, weighted vaginal cones or obturators may be placed into the vagina during Kegel exercises. These provide resistance against which pelvic floor muscles can work.
PFMT for women with urinary incontinence compared with no treatment, placebo or sham treatment, or other inactive control treatment has been reviewed (Dumoulin, 2014a). Although interventions vary considerably, women who performed PFMT are more likely to report cure or improved incontinence and improved continence-specific quality of life than women who did not use PFMT. The exercising women also objectively demonstrated less leakage during office-based pad testing. Prognostic indicators that may predict a poor response to PFMT for SUI treatment include severe baseline incontinence, prolapse beyond the hymenal ring, prior failed physiotherapy, a history of prolonged second-stage labor, BMI >30 kg/m2, high psychological distress, and poor overall physical health (Hendriks, 2010).
As an alternative to active pelvic floor contraction, a vaginal probe may be used to deliver low-frequency electrical stimulation to the levator ani muscles. Although the mechanism is unclear, this passive electrical stimulation may be used to improve either SUI or urgency urinary incontinence (Indrekvam, 2001; Wang, 2004). With urgency urinary incontinence, traditionally a low frequency is applied, whereas for SUI, higher frequencies are used. Electrical stimulation may be implemented alone or more commonly in combination with active PFMT.
Many behavioral techniques, often considered together as biofeedback therapy, measure physiologic signals such as muscle tension and then display them to a patient in real time. In general, visual, auditory, and/or verbal feedback cues are directed to the patient during these therapy sessions. Specifically, during biofeedback for active PFMT, a sterile vaginal probe that measures pressure changes within the vagina during levator ani muscle contraction is typically used. Visual readings reflect an estimate of muscle contraction strength. Treatment sessions are individualized, dictated by the underlying dysfunction, and modified based on response to therapy. In many cases, reinforcing sessions at various subsequent intervals may also prove advantageous.
Various food groups that may have high acidity or caffeine content can lead to greater urinary frequency and urgency. Dallosso and colleagues (2003) found consumption of carbonated drinks to be associated with development of urgency urinary incontinence symptoms. Accordingly, elimination of these dietary irritants may benefit these women. In addition, certain dietary supplements such as calcium glycerophosphate (Prelief) have been shown to decrease urgency and frequency symptoms (Bologna, 2001). This is a phosphate-based product and is thought to buffer urine acidity.
Women with urgency urinary incontinence may feel voiding urges as frequently as every 10 to 15 minutes. Initial goals extend voidings to half-hour intervals. Tools used to achieve this include Kegel exercises during waves of urgency or mental distraction techniques during these times. Scheduled voiding, although used primarily for urgency urinary incontinence, may also be helpful for those with SUI. For these patients, regularly scheduled urination leads to an empty bladder during a greater percentage of the day. Because some women will leak urine only if bladder volumes surpass a specific threshold, frequent emptying can significantly decrease incontinence episodes.
Estrogen has been shown to increase urethral blood flow and increase α-adrenergic receptor sensitivity, thereby increasing urethral coaptation and urethral closure pressure. Hypothetically, estrogen may also increase collagen deposition and increase vascularity of the periurethral capillary plexus. These are purported to improve urethral coaptation. Thus, for incontinent women who are atrophic, administration of exogenous estrogen is reasonable.
Estrogen is commonly administered topically, and many different regimens are appropriate. At our institution, we use conjugated equine estrogen cream (Premarin cream) administered daily for 2 weeks, then twice weekly thereafter. Although no data are available to address the duration of treatment, women may be treated chronically with topical estrogen cream. Alternatively, oral estrogen may be prescribed if other menopausal symptoms for which estrogen would be beneficial coexist (Chap. 22). However, despite these suggested benefits, a consensus regarding estrogen’s beneficial effects on the lower urinary tract has not been reached. Specifically, some studies have shown worsening or development of urinary incontinence with systemic estrogen administration (Grady, 2001; Grodstein, 2004; Hendrix, 2005; Jackson, 2006).
Treatment of Stress Urinary Incontinence
Pharmaceutical treatment plays a minor role in the treatment of women with SUI. However, for women with mixed urinary incontinence, a trial of imipramine is reasonable to aid urethral contraction and closure. As discussed earlier, this tricyclic antidepressant has α-adrenergic effects, and the urethra contains a high content of these receptors.
Pessary and Urethral Inserts
Certain pessaries have been designed to treat incontinence as well as pelvic organ prolapse. These “incontinence pessaries” are designed to reduce downward excursion or funneling of the urethrovesical junction (Fig. 24-16). This provides bladder neck support and thereby helps to reduce incontinence episodes. The success of pessary use in the treatment of urinary incontinence is variable, dependent on the amount of prolapse and other factors. Not all women are appropriate candidates for devices, nor will all desire long-term management of incontinence or prolapse with these.
A large prospective trial comparing incontinence pessaries and behavioral therapy for women with SUI demonstrated that 40 and 49 percent of patients were either much or very much improved at 3 months, respectively. The women randomized to behavioral therapy reported greater treatment satisfaction, and a greater percentage reported no bothersome incontinence symptoms (Richter, 2010b).
As an alternative to pessaries, urethral occlusive devices include urethral inserts (FemSoft and Reliance Urinary Control Insert) and urethral patches (CapSure and Re/Stor). Urethral inserts conform to the urethra and create a seal at the bladder neck to prevent accidental leakage. During routine bathroom visits, the insert is removed, discarded, and replaced with a fresh insert. Although data are limited on the effectiveness of inserts, adverse effects of mucosal irritation or superficial bacterial infection are generally minor. In an observational study of 150 women, Sirls and associates (2002) found significantly reduced rates of incontinence episodes with the FemSoft device. With urethral patches, a water-tight seal is created over the urethra after the patch adheres to surrounding periurethral skin using adhesive gel. Similarly, although success rates vary between 44 and 97 percent, these devices are associated with minimal adverse effects (Bellin, 1998; Versi, 1998).
For those who are unsatisfied with or do not desire conservative management, surgery may be an appropriate next step for SUI. As noted earlier, urethral support is integral to continence. Thus, surgical procedures that recreate this support often diminish or cure incontinence. In general, these surgical procedures are believed to prevent bladder neck and proximal urethra descent during increases in intraabdominal pressure and are grouped as shown in Table 23-4. General postoperative risks for continence surgeries include lower urinary tract injury, failure to correct or recurrence of SUI, and creation of de novo voiding dysfunction such as urgency or retention.
TABLE 23-4Summary of Incontinence Procedures ||Download (.pdf) TABLE 23-4 Summary of Incontinence Procedures
|Procedure ||Description ||Indication ||Comments |
|Midurethral slings: |
|Midurethra supported by mesh placed: |
by retropubic approach
by transobturator approach
|Effective short-term treatment, rapid postoperative recovery; TVT with long-term efficacy data; further study required to determine effectiveness of TOT in patients with ISD |
|Retropubic urethropexy ||Pubocervical fascia attached to: Cooper ligament (Burch) or symphysis pubis (MMK) ||SUI ||Effective long-term treatment; requires surgeon experience; less reproducible benefits than midurethral sling procedure |
|Pubovaginal slings ||Bladder neck supported by fascial strip attached to anterior abdominal wall ||ISD; failed SUI procedure ||Effective long-term treatment; may be useful when synthetic material is not desirable; requires graft isolation |
|Urethral injection ||Bulking agent into urethral submucosa ||ISD ||Also for SUI in poor surgical candidates; may require several repeated injections |
|Needle suspension ||Proximal urethra suspended by anterior abdominal wall ||SUI ||Low long-term success rates; no longer recommended for SUI |
|Paravaginal defect repair ||Lateral vaginal wall attached to ATFP ||Vaginal prolapse ||No longer recommended for SUI |
The therapeutic mechanism of these slings is based on the integral theory hypothesized by Petros and Ulmsten (1993). In brief, control of urethral closure involves the interplay of three structures: the pubourethral ligaments, the suburethral vaginal hammock, and the pubococcygeus muscle. Loss of these supports lead to urinary incontinence and pelvic floor dysfunction. Midurethral slings are believed to recreate this structural support.
There are different variations of these procedures, but all use a vaginal approach to place synthetic mesh beneath the midurethra. Recovery from midurethral sling placement is rapid, and many gynecologists provide this surgery on an outpatient basis. As such, these are often a popular surgical treatment for SUI. Simplistically, they are classified according to the route of placement and are subdivided into those using a retropubic or a transobturator approach.
For the retropubic approach, several commercial kits are available, and one commonly used is the tension-free vaginal tape (TVT). With this, the sling (tape) is placed through a vaginal incision to create a hammock beneath the urethra. On each side of the urethra, the sling’s arms are brought out to the lower anterior abdominal wall and affixed. For this procedure, sharp trocars traverse the retropubic space as illustrated in Section 45-3 of the atlas. Thus, bladder puncture and retropubic space vessel laceration are specific risks. Many studies attest to this procedure’s efficacy (Holmgren, 2005; Song, 2009). One prospective observational study confirmed the long-term safety and efficacy of the TVT device. At 17 years, 87 percent were subjectively cured or significantly improved (Nilsson, 2013).
For the transobturator tape (TOT) approach, various kits are also available, and sling material is directed bilaterally through the obturator foramen and underneath the midurethra. The entry point overlies the proximal tendon of the adductor longus muscle of the inner thigh as shown in Section 45-4. This approach was introduced with the intent to reduce the vascular and lower urinary tract injury risks that can be associated with traversing the retropubic space.
The TOT is indicated for primary SUI secondary to urethral hypermobility. For this, subjective success rates range from 73 to 92 percent up to 5 years after surgery (Abdel-Fattah, 2012; Laurikainen, 2014; Wai, 2013). However, abundant longer-term data regarding the efficacy of transobturator approaches are lacking. Moreover, in patients with SUI secondary to ISD, the value of TOT is unclear as results are conflicting and data are limited (Miller, 2006; O’Connor, 2006; Richter, 2010a).
In comparing these two, one multicenter randomized study of 597 found no significant differences in objective and subjective success rates at 12 months between the retropubic (80.8 and 62.2 percent) and the transobturator (77.7 and 55.8 percent) routes, respectively (Richter, 2010a). The retropubic route had a significantly higher rate of postoperative voiding dysfunction requiring reoperation, whereas the transobturator route resulted in more neurologic symptoms. Overall quality of life and satisfaction scores with the two procedures were similar. Others have found similar findings with respect to procedure–related complications. Namely, the retropubic route has a higher rate of bladder injury but required a decreased use of anticholinergic medication postoperatively (Barber, 2006; Brubaker, 2011).
Modification of the TVT and TOT procedure is seen with the minimally invasive slings, sometimes called “microslings” or “minislings.” With this technique, an 8-cm-long strip of polypropylene synthetic mesh is placed across and beneath the midurethra through a small vaginal incision. Mesh is not threaded through the retropubic space as with TVT, nor does it perforate the obturator membrane as with TOT. That said, lower urinary tract injury is not completely averted with this method. Initial results for the minislings suggested high objective and subjective cure rates (Neuman, 2008). However, in one study, the minisling group had a higher proportion of patients with more severe incontinence 1 year after surgery than those in the retropubic sling group (Barber, 2012).
In March 2013, the FDA issued an update regarding considerations about surgical mesh for SUI. In that statement, the established safety and efficacy of mesh sling procedures for the treatment of SUI were upheld for full-length multiincision operations. They further noted that the safety and effectiveness of minislings had not yet been adequately demonstrated.
This group includes the Burch and Marshall-Marchetti-Krantz (MMK) colposuspension procedures. Traditionally performed via laparotomy, these suspend and anchor the pubocervical fascia to the musculoskeletal framework of the pelvis (Section 45-2). With the advent of less invasive procedures for SUI, such as the midurethral sling, these techniques are less commonly performed. The Burch technique uses the strength of the iliopectineal ligament (Cooper ligament) to lift the anterior vaginal wall and the periurethral and perivesicular fibromuscular tissue. In contrast, during MMK surgery, the periosteum of the symphysis pubis is used to suspend these tissues. Thus, an added risk for MMK is osteitis pubis.
Retropubic urethropexy effectively treats SUI. One-year overall continence rates range between 85 and 90 percent, and the 5-year continence rate approximates 70 percent (Lapitan, 2009). As another indication, data suggest that Burch retropubic urethropexy performed concurrently with abdominal sacrocolpopexy (ASC) may significantly reduce rates of later, postoperative de novo SUI (Chap. 24) (Brubaker, 2008a). In support of this practice, a 7-year follow-up study showed that patients undergoing ASC and prophylactic Burch urethropexy still demonstrated lower de novo SUI rates than women receiving ASC alone (Nygaard, 2013).
With this surgery, a strip of either rectus fascia or fascia lata is placed under the bladder neck and through the retropubic space. The ends are secured at the level of the rectus abdominis fascia (Section 45-5). This surgery has traditionally been used for SUI stemming from ISD. In addition, this procedure may also be indicated for patients with prior failed continence operations.
Urethral Bulking Agent Injection
Using cystoscopic guidance, agents can be injected into the urethral submucosa to “bulk up” the mucosa and improve coaptation. Surgical steps and agent types are illustrated in Section 45-6. This option has traditionally been indicated for women who have stress incontinence associated with ISD. However, the Food and Drug Administration (FDA) has broadened criteria for their use to include patients with less severe leak point pressures. Thus, those with leak point pressures <100 cm H2O may also be candidates (McGuire, 2006). Additionally, this office procedure is a useful alternative for women with SUI who have multiple medical problems and are thus poor surgical candidates.
Transvaginal Needle Procedures and Paravaginal Defect Repair
In the 1960s through 1980s, needle suspension procedures such as the Raz, Pereyra, and Stamey techniques were popular operations for SUI but have now largely been replaced by other methods. In brief, these surgeries use specially designed ligature carriers to place sutures through the anterior vaginal wall and/or periurethral tissues and suspend them to various levels of the anterior abdominal wall. These rely on the strength and integrity of the periurethral tissue and abdominal wall strength to correct urethral hypermobility and prevent bladder neck and proximal urethra descent. Although initial cure rates are satisfactory, the durability of these procedures decreases with time. Success rates range from 50 to 60 percent, well below rates found with other current continence procedures (Moser, 2006). Failure stemmed largely from “pull-through” of sutures at the level of the anterior vaginal wall.
In addition, abdominal paravaginal defect repair (PVDR) is a surgical procedure that corrects lateral support defects of the anterior vaginal wall. The technique involves suture attachment of the lateral vaginal wall to the arcus tendineus fascia pelvis. Currently, PVDR is primarily a prolapse-correcting operation. Although previously used to correct SUI, long-term data show this to no longer be a superior method for primary treatment of SUI (Colombo, 1996; Mallipeddi, 2001).
Treatment of Urgency Urinary Incontinence
These medications appear to work at the level of the detrusor muscle by competitively inhibiting acetylcholine at muscarinic receptors (M2 and M3) (Miller, 2005). These agents thereby blunt detrusor contractions to reduce the number of incontinence episodes and volume lost with each. These medications are significantly better than placebo at improving symptoms of urgency urinary incontinence and overactive bladder. However, in a Cochrane database review, Nabi and colleagues (2006) reported that the reduction in baseline urgency incontinence episodes per day reflects only a modest benefit.
These frequently used drugs competitively bind to cholinergic receptors (Table 23-5). As noted, muscarinic receptors are not limited to the bladder. Thus, drug side effects may be significant. Of these, dry mouth, constipation, and blurry vision are common, and dry mouth is a primary reason for drug discontinuation (Table 23-6). Importantly, anticholinergics are contraindicated in those with narrow-angle glaucoma.
TABLE 23-5Pharmacologic Treatment of Overactive Bladder ||Download (.pdf) TABLE 23-5 Pharmacologic Treatment of Overactive Bladder
|Drug Name ||Brand Name ||Drug Type ||Dosage a ||Available Doses |
|Oxybutynin (short-acting) ||Ditropan ||Antimuscarinic ||2.5–5 mg three times daily ||5-mg tablet, 5 mg/mL syrup |
|Oxybutynin (long-acting) ||Ditropan XL ||See above ||5–30 mg daily ||5-, 10-, 15-mg tablet |
|Oxybutynin (transdermal) ||Oxytrol ||See above ||3.9 mg/d; change patch twice weekly ||36-mg patch, 8 per carton |
|Oxybutynin (transdermal) 10% gel 3% gel ||Gelnique ||See above ||Apply 1 g dailyApply 3 pumps daily ||1-g packet, 30 per carton |
30 doses per bottle
|Tolterodine (short-acting) ||Detrol ||See above ||1–2 mg twice daily ||1-, 2-mg tablet |
|Tolterodine (long-acting) ||Detrol LA ||See above ||2–4 mg daily ||2-, 4-mg capsule |
|Fesoterodine fumarate ||Toviaz ||See above ||4–8 mg daily ||4-, 8-mg tablets |
|Trospium chloride ||Sanctura ||Antimuscarinic quaternary amine ||20 mg twice daily ||20-mg tablet |
|Trospium chloride ||Sanctura XR ||See above ||60 mg daily ||60-mg tablet |
|Darifenacin ||Enablex ||M 3-selective antimuscarinic ||7.5–15 mg daily ||7.5-, 15-mg tablet |
|Solifenacin ||Vesicare ||M 3-selective antimuscarinic ||5–10 mg daily ||5-, 10-mg tablets |
|Imipramine hydrochloride ||Tofranil ||Tricyclic antidepressant, anticholinergic, α-adrenergic, antihistamine ||10–25 mg one to four times daily. Begin with 10–25 mg nightly. ||10-, 25-, 50-mg tablets |
|Mirabegron ||Myrbetriq ||β 3 adrenergic agonist ||25–50 mg daily ||25-, 50-mg tablets |
TABLE 23-6Potential Anticholinergic Side Effects ||Download (.pdf) TABLE 23-6 Potential Anticholinergic Side Effects
|Side Effect ||Potential Clinical Consequence |
Increased pupil size
Decreased visual accommodation
Decreased bronchial secretions
Increased heart rate
Decreased detrusor function
Decreased gastrointestinal mobility
Gingival and buccal ulceration
Small-airway mucus plugging
Angina, myocardial infarction
Bladder distention and urinary retention
Because of these side effects, the therapeutic goal of bladder M3 blockade with these antimuscarinic agents is often limited. Accordingly, drug selection is tailored, and efficacy is balanced against tolerability. For example, Diokno and associates (2003) found oxybutynin to be more effective than tolterodine. However, tolterodine was associated with lower side effect rates. Tolterodine and fesoterodine have also been compared in a randomized study of 1135 patients. Fesoterodine was found to perform better than tolterodine, although once again, side effects were lowest in the tolterodine group (Chapple, 2008). A population-based study reported that only 56 percent of women felt their overactive bladder medication was effective, and half stopped taking the medication (Diokno, 2006).
Most side effects attributed to oxybutynin stem from its secondary metabolite that follows liver metabolism. Therefore, to minimize oral oxybutynin side effects, a transdermal patch was designed to decrease the “first-pass” effect of this drug. This leads to decreased liver metabolism and fewer systemic cholinergic side effects. Dmochowski and coworkers (2003) found fewer anticholinergic side effects with transdermal oxybutynin compared with long-acting oral tolterodine.
Transdermal oxybutynin (Oxytrol) is supplied as a 7.6 × 5.7 cm patch that is applied to the abdomen, hip, or buttock; worn continuously; and changed twice weekly. Each patch contains 36 mg of oxybutynin and delivers approximately 3.9 mg daily. Application-site pruritus is the most frequent side effect, and varying the application site may minimize skin reactions (Sand, 2007). A transdermal oxybutynin gel (Gelnique), available in 3- and 10-percent strengths, is applied daily to skin of the abdomen, upper arms/shoulders, or thigh, and application sites are rotated.
This agent is less effective than tolterodine and oxybutynin but displays α-adrenergic and anticholinergic characteristics. Therefore, it is occasionally prescribed for those with mixed urinary incontinence. Importantly, doses of imipramine used to treat incontinence are significantly lower than those used to treat depression or chronic pain. In our experience, this minimizes the theoretical risk of drug-related side effects.
Selective Muscarinic-receptor Antagonists
These drugs were introduced with the aim of reducing anticholinergic side effects. The agents are all M3-receptor selective antagonists and include solifenacin (Vesicare), trospium chloride (Santura), and darifenacin (Enablex). Advantages of increased urgency warning time and decreased muscarinic side effects have been shown in randomized controlled studies (Cardozo, 2004; Chapple, 2005; Haab, 2006; Zinner, 2004). However, although the side-effect profiles of these drugs are potentially more attractive, they have not been proved superior in efficacy to nonselective muscarinic agents (Hartmann, 2009).
More recently, a β3-adrenergic receptor agonist, mirabegron (Myrbetriq), has been introduced into the U.S. pharmaceutical market for the treatment of urgency urinary incontinence, urgency, and frequency. Activation of these receptors results in relaxation of the detrusor smooth muscle and increased bladder capacity. Most commonly reported adverse reactions include hypertension, nasopharyngitis, UTIs, dry mouth, and headache (Herschorn, 2013).
Urine storage and bladder emptying require a complex coordinated interaction of spinal cord and higher brain centers, peripheral nerves, urethral and pelvic floor muscles, and the detrusor muscle. If any of these levels are altered, normal micturition is lost. To overcome these problems, electrical nerve stimulation, also called neuromodulation, has been used. InterStim is the only implantable neuromodulation system approved by the FDA for treatment of refractory urgency urinary incontinence and for treatment of anal incontinence. It may be also considered for those with pelvic pain, interstitial cystitis, and defecatory dysfunction, although it is not FDA-approved for these indications. Sacral neuromodulation is not considered primary therapy and is typically offered mainly to women who have exhausted pharmacologic and conservative options.
This outpatient surgically implanted device contains a pulse generator and electrical leads that are placed into the sacral foramina to modulate bladder and pelvic floor innervation. Its mode of action is incompletely understood but may be related to somatic afferent inhibition that interrupts abnormal reflex arcs in the sacral spinal cord involved in the filling and evacuation phases of micturition.
Implantation is typically a two-stage process. Initially, leads are placed and attached to an externally worn generator (Section 45-12). After placement, frequency and amplitude of electrical impulses can be adjusted and tailored to maximize effectiveness. If a 50-percent or greater improvement in symptoms is noted, then internal implantation of a permanent pulse generator is planned. This procedure is minimally invasive and is typically completed in a day-surgery setting. Surgical complications are rare but may include pain or infection at the generator insertion site.
Although its use is often reserved for those who have been unsuccessfully treated with behavioral or pharmacologic therapy, this modality is effective for urinary symptom treatment. Studies have found improvement rates ranging from 60 to 75 percent, and cure rates approximating 45 percent (Janknegt, 2001; Schmidt, 1999; Siegel, 2000). Sustained improvement from baseline incontinence parameters has been shown at long-term follow-up. One 3-year study reported a 57-percent reduction in incontinence episodes per day, and similar findings were found in a separate 5-year study (Kerrebroeck, 2007; Siegel, 2000). A systematic review of 17 case series at follow-up periods of 3 to 5 years similarly reported 39 percent of patients cured and 67 percent with greater than 50-percent improvement in incontinence symptoms (Brazzelli, 2006).
Percutaneous Tibial Nerve Stimulation
Sometimes referred to as posterior tibial nerve stimulation, percutaneous tibial nerve stimulation (PTNS) is becoming a more common therapy for refractory urgency urinary incontinence. It involves percutaneous needle electrode placement into an area cephalic to the medial malleolus of the lower extremity. Electrical pulses are sent via a generator to the tibial nerve. This nerve originates from spinal roots L4-S3, and its stimulation leads to retrograde neuromodulation. Multicenter studies have demonstrated its efficacy compared with sham or with primary treatment with anticholinergic medication (Peters, 2009, 2010; MacDiarmid, 2010).
Injection of botulinum toxin A (onabotulinumtoxinA) into the bladder wall is approved for the treatment of idiopathic detrusor overactivity. Three placebo-controlled studies showed the effectiveness of this treatment (Anger, 2010). All three used cystoscopic injection of 200 units of botulinum toxin A versus placebo, and each demonstrated significantly improved continence rates. Improvement occurred as early as 4 weeks after injection (Brubaker, 2008b; Flynn, 2009; Khan, 2010; Sahai, 2007). Urinary retention—defined a postvoid residual volume measuring > 200 mL—is a common side effect and developed in 27 to 43 percent of patients in these randomized trials. Most patients are asymptomatic, but patients receiving botulinum toxin A for overactive bladder or urgency urinary incontinence are counseled that temporary self-catheterization may be required after injection.
More recently, one double-blind, randomized trial compared oral anticholinergic therapy against injections of 100 units of botulinum toxin A in women with idiopathic urgency urinary incontinence. Investigators found comparable reductions in incontinence episodes. The botulinum toxin A group was less likely to complain of dry mouth and more likely to have complete resolution of urgency urinary incontinence (Visco, 2012). In the injection group, the rate of catheter use for urinary retention was only 5 percent. At our institution, we use 100 units for women with idiopathic overactive bladder.
A patient can expect the effects of the toxin to wane over time. In a small study describing the need for repeat injections, 20 patients from a cohort of 34 received a second injection, and nine patients received up to four injections. These repeat injections appear to be equally effective as the primary injection. Median time between injections is approximately 377 days (Sahai, 2010).