Sacral Nerve Stimulation (SNS)


Sacral Nerve Stimulation

Sacral Nerve Stimulation (SNS) is a novel therapy that may be able to help certain people who experience bladder and bowel problems. Where successful, the treatment can be a life changing therapy. SNS can help to restore normal bladder or bowel function and has been used to treat 200,000 worldwide. Approved initially over 20 years ago for bladder incontinence, it was noted to be effective in patients with bowel incontinence and has since been approved for treatment of bowel issues with great success. This therapy addresses the communication problem between the bladder/bowel and the brain that may be causing symptoms. It is performed in two stages, both under sedation as an outpatient where an initial trial of therapy is performed using an external stimulating device and if successful the stimulator is placed under the skin so that it is totally internal. Bowel management, specifically, is still an underdeveloped area of care across the US. At Virginia Surgery Associates, we are working hard to ensure that everyone has easy access to the right level of information and support, to ensure they are able to be assessed and prescribed the correct treatment for their individual needs.

What does Sacral Nerve Stimulation treat?
Sacral Nerve Stimulation can, in some cases, effectively treat fecal incontinence. It may also effectively treat overactive bladder, including the frequent, strong, and sudden urge to go to the toilet.

How do you know if it’s right for you?
SNS is a therapy that is considered when conservative options (such as lifestyle and dietary changes, medication or biofeedback) have had limited or no success, or are too difficult to live with. A specialist doctor will assess each individual’s suitability for the treatment. SNS is performed in two stages, the first is an evaluation/test phase and the next is the implant phase. The evaluation phase allows your doctor to assess whether or not your symptoms will be significantly reduced by SNS.

Before you take part in an evaluation, you will be asked to take a few weeks during your normal routine at home recording your toilet habits and symptoms, in a diary, to use as a base for future comparison.

Evaluation Phase
To evaluate SNS as a therapy, a thin temporary wire is inserted near the sacral nerves in your lower back, [near your tailbone] which control the bladder/bowel. The wire is then connected to a small discrete external device which delivers stimulation to the nerves. This external device, houses a battery which is worn on a belt for the duration of the evaluation. The procedure normally takes less than an hour and is generally completed as an outpatient. After the temporary wire is inserted you’ll go home and go about your daily life, continuing to record your toilet habits during this test in a new diary. After two weeks of the home evaluation, your doctor will explain and discuss the results with you. Several measures will be used to assess whether or not you will benefit from SNS. Depending on your symptoms, this may include recording the number of incontinence episodes before and after the test, quality of life assessments, and patient satisfaction.

Implant Phase
Following a positive evaluation, you may be offered an implanted device, called a Neurostimulator (similar to a pacemaker). The implant is usually placed just beneath the skin in the upper buttock. It’s about the same size as a silver dollar coin. A thin lead is also implanted in the lower back and connected to the device, with the battery lasting approximately 5 years. Should your evaluation be unsuccessful (only about 10% of the time), the temporary wire will be removed in clinic and your specialist doctor will either consider repeating the test or discuss other options with you.

The science behind Sacral Nerve Stimulation
One way the brain controls our body’s muscles and movements is through electrical messages, which are carried by nerves. These nerves have major routes with smaller pathways running off them. One major route runs from the brain, along the spinal cord and through the lower back called the sacral area. Here, nerve paths split off and go in different directions, some to the pelvic area. The muscles in the pelvic area, such as the pelvic floor, urethral sphincters, bladder and anal sphincter muscles are controlled by the brain through nerves that run from the sacral area. Our sensations, such as fullness in the bladder or rectum, are also relayed to the brain via these nerve routes. SNS helps to correct inappropriate, unwanted or even erroneous messages sent along these nerve pathways.

Photos below are the actual stimulator device


Description of Pelvic Floor Testing


Patient Instructions for Anorectal Physiology (ARP) Testing

Anal Manometry
Anal manometry is performed to evaluate patients with constipation and/or fecal incontinence. Anal manometry measures pressures of the anal sphincter muscles and the sensation in the rectum. The test takes approximately 30 minutes. A nurse will review the procedure with you, take a brief health history and answer any questions you may have. The person then lies on his left side. A small, flexible tube, about the size of a thermometer, is inserted into the rectum.. During the test the nurse asks the person to squeeze or relax the anal muscle. The anal sphincter muscle pressures are measured during each of these maneuvers. To squeeze, the person tightens the sphincter muscles as if trying to prevent anything from coming out. The doctor may perform two other tests. First, an anal EMG which is a test to evaluate the nerve supply to the anal muscle. In addition an ultrasound of the anal sphincter may be performed. After the examination, you may drive yourself home, eat and go about your normal activities.

Anal Sphincter EMG (Electromyography)
EMG measures the electrical activity in the pelvic floor (puborectalis) muscle. In constipated patients, an EMG is performed using postage stamp sized skin sensor applied near the anal opening. The patient relaxes squeezes and pushes. A computer records sphincter muscle electrical activity. Anal sphincter electromyography confirms the proper muscle contractions during squeeze and muscle relaxation during push. In people with non-relaxing puborectalis, the tracing of electrical activity gets bigger, instead of smaller, during a push. Normal anal EMG activity with low anal squeeze pressures on manometry may indicate a torn sphincter muscle that could be repaired.

In incontinent patients, the nerve that controls the sphincter muscle may have been damaged. In order to test for this, a fine sensor attached to the tip of the gloved examining finger of the physician is inserted into the anal canal. A gentle electrical impulse is delivered which most patients cannot feel. The time it takes for the muscle to respond is recorded and the procedure repeated on the other side.

Rectal Ultrasound
This painless exam involves inserting a small probe into the anal canal and using sound waves, a picture of the anal sphincter is generated. This reveals any potential abnormalities or injury in the muscle.

Risks:
Anorectal manometry is a safe, low risk procedure and is unlikely to cause any pain. Complications can occur, but are rare: it is possible that a perforation (tearing) or bleeding of the intestinal wall could occur. Equipment failure is extremely unlikely, but does remain a remote possibility.