Percutaneous Tibial Nerve Stimulation for the Treatment of Overactive Bladder

Judith Walsh, MD, MPH

Disclosures

CTAF 

In This Article

Background

Urinary incontinence, defined as the involuntary loss of urine, is common, particularly in women. Despite its significant consequences, it is often under recognized and under treated. In one survey of a multi-ethnic population, only 45% of women who reported at least one incontinence episode a week had sought out care for their symptoms of incontinence.[1]

There are several types of incontinence: urge incontinence, stress incontinence, mixed incontinence and overflow incontinence. Urge incontinence is thought to be related to detrusor overactivity. Stress incontinence is urine loss that occurs with an increase in abdominal pressure, and is often due to urethral hypermobility. It is the commonest type of incontinence in younger women. Mixed incontinence (urge and stress) is the commonest type of incontinence in older women. Overflow incontinence describes dribbling or leaking associated with incomplete bladder emptying.

OAB Definition

The term "voiding dysfunction" has been used to refer to urinary incontinence, urinary retention and symptoms of frequency and urgency. Overactive bladder is a specific type of voiding dysfunction that includes any or all of the following symptoms: urinary frequency (bothersome urination eight or more times a day or two more times at night), urinary urgency (the sudden, strong need to urinate immediately), urge incontinence (leakage or gushing of urine that follows a sudden strong urge) and nocturia (awakening two or more times at night to urinate). It can be associated with neurologic conditions, such as Parkinson's disease or multiple sclerosis, but in most cases the cause is unknown. OAB can significantly impact quality of life; it can impact physical functioning, sexual function and social interactions.

Standard Treatments

The standard treatments for overactive bladder include lifestyle changes, bladder training, pelvic floor muscle training and anticholinergic (anti-muscarinic) drugs. Additional treatments for some types of incontinence include pessary placement and surgery. Sacral nerve stimulation has also been tried.

1. Lifestyle Changes. Weight loss has been shown to decrease episodes of urinary incontinence, although the impact seems to be more on stress than on urge incontinence.[2–4] Other suggested approaches include elimination of alcohol, coffee or tea or carbonated beverages.

2. Bladder Training. The principles of bladder training include frequent voluntary voiding in order to keep the bladder volume low and therefore avoid detrusor contractions and timing of CNS and pelvic mechanisms to inhibit the urge to urinate. Patients are taught to use timed voiding (voiding at regular intervals regardless of urge to urinate) and also to use relaxation techniques to suppress urgency that occurs between voids. Over time the interval between voids is increased. Successful training can occur over a several week period.

3. Pelvic Muscle Exercises. Pelvic muscle exercises (or Kegels) focus on strength training of the pelvic floor muscles. When patients are trained to do them correctly, they can improve symptoms of stress, urge or mixed incontinence.

4. Biofeedback. Biofeedback is sometimes used as a supplement to bladder training. The biofeedback focuses on anorectal or vaginal biofeedback to help patients contract the pelvic muscles, and includes how to respond to feelings of urgency.[5]

5. Pharmacologic Therapy. The most commonly used drugs are anticholinergic drugs that have anti-muscarinic properties. Their main mechanism of action is to increase bladder capacity and decrease urgency.[6] Systematic reviews have shown that these drugs are significantly better than placebo in decreasing the number of incontinent episodes and voids over a 24 hour period.[7,8] In general the efficacy of these drugs increases up to four weeks.

Although the anticholinergic drugs are efficacious for urge incontinence, their side effects can significantly limit their use. The commonest side effects include dry mouth and constipation. Other side effects can include blurred vision, drowsiness and decreased cognitive function. About 80% of patients discontinue treatment after a year,[9] and about 17% of the discontinuation is because of adverse side effects.[10]

Other medications that have been used for some types of urinary incontinence include alpha-adrenergic agents, duloxitene and topical estrogen. Botulinum toxin has also been injected into the detrusor muscle with some success, although it can sometimes cause post treatment urinary retention.

6. Surgery. Surgery is sometimes performed for incontinence refractory to other treatments, but can be associated with significant complications. It is not a standard treatment for OAB.

7. Pessaries. Specially fitted pessaries can be used in women with prolapse and can relieve symptoms of incontinence.

Neurologic Stimulation Therapy

The theory of neurologic stimulation therapy is that stimulation of the nerves can stimulate pelvic muscle contractions or detrusor contractions. The initial studies of neurologic stimulation therapy focused on the sacral nerve.[11–14] Although sacral nerve stimulation can improve symptoms of incontinence, the implantable sacral nerve stimulators are somewhat invasive. Currently many studies are focusing on a less invasive approach, percutaneous tibial nerve stimulation (PTNS).

History of PTNS

PTNS was developed by Dr. Marshall Stoller at UCSF as a less invasive alternative to sacral nerve stimulation (SNS). The first devices were called Stoller Afferent Nerve Stimulators (SANS). Although the exact mechanism of action is unclear, it is thought to interrupt abnormal reflex arcs that may affect bladder dysfunction.[15] PTNS involves a needle electrode being inserted into the posterior tibial nerve at the medial malleolus of the ankle. It is inserted about 3–4 centimeters. The electrode is then connected to a hand held nerve stimulator which sends an electrical impulse to the nerve. This nerve impulse is then transmitted to the sacral plexus which regulates the control of bladder and pelvic floor muscles. The maximum treatment intensity is determined in the following way: the stimulus intensity is increased slowly until the patient's great toe begins to curl. The level at which the patient's toe curls is determined to be the maximum intensity for treatment. Currently a treatment course is defined as one treatment a week for 12 weeks. Each treatment session lasts 30 minutes. "Maintenance treatment" is given at intervalsdetermined by whether and when symptoms recur.

The goal of this assessment will be to focus on the role of PTNS in the treatment of overactive bladder.

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