Sacral nerve stimulation

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Sacral nerve stimulation

Sacral nerve stimulation, also termed sacral neuromodulation, is a type of medical electrical stimulation therapy.

Contents

It typically involves the implantation of a programmable stimulator subcutaneously, which delivers low amplitude electrical stimulation via a lead to the sacral nerve, usually accessed via the S3 foramen.

The U.S. Food and Drug Administration has approved InterStim Therapy, by Medtronic, as a sacral nerve stimulator for treatment of urinary incontinence, high urinary frequency and urinary retention. Sacral nerve stimulation is also under investigation as treatment for other conditions, including constipation brought on by nerve damage due to surgical procedures. An experimental procedure for constipation in children is being conducted in Nationwide Children's Hospital.

In the event that the nerves and the brain are no longer communicating effectively, resulting in a bowel/bladder disorder, this type of treatment is designed to imitate a signal sent via the central nervous system.

One of the major nerve routes is from the brain, along the spinal cord and through the back. This is commonly referred to as the sacral area. This area controls the everyday function of the pelvic floor, urethral sphincter, bladder and bowel. By stimulating the sacral nerve (located in the lower back), a signal is sent that manipulates a contraction within the pelvic floor. Over time these contractions rebuild the strength of the organs and muscles within it. This effectively alleviates all symptoms of urinary/faecal disorders, and in many cases eliminates them completely.[ citation needed ]

Medical uses

Urge incontinence

Many studies have been initiated using the sacral nerve stimulation (SNS) technique to treat patients that suffer with urinary problems.[ citation needed ] When applying this procedure, proper patient screening is essential, because some disorders that affect the urinary tract (like bladder calculus or carcinoma in-situ) have to be treated differently. Once the patient is selected, he receives a temporary external pulse generator connected to wire leads at S3 foramina for 1–2 weeks. If the person's symptoms improve by more than 50%, he receives the permanent wire leads and stimulator that is implanted in the hip in the subcutaneous tissue. The first follow-up happens 1–2 weeks later to check if the permanent devices are providing improvement in the user's symptoms and to program the pulse generator adequately.[ citation needed ]

Bleeding, infection, pain and unwanted stimulation in the extremities are some of the complications resulting from this therapy. Currently, battery replacements are necessary 5–10 years after implementation depending upon the strength of the stimulation therapy. (The newest interstim's battery can be wirelessly recharged (roughly weekly) using a paddle placed against the skin outside the implant.) This procedure has shown long term success rate that ranges from 50% to 90%, and one study concluded that it was a good option for patients with lower urinary tract dysfunction refractive to conservative and pharmacological interventions. [1]

Fecal incontinence

Fecal incontinence, the involuntary loss of stool and flatus release afflicting mainly elderly people, can also be treated with sacral nerve stimulation as long as patients have intact sphincter muscles. The FDA approved the approach for treating the fecal incontinence in March 2011. The etiology is not well understood yet and both conservative treatments (like antidiarrheics, special diet and biofeedback) and surgical treatments for this disorder are not regarded as ideal options. [2]

Pascual et al. (2011) revised the follow-up results of the first 50 people that submit to sacral nerve stimulation (SNS) to treat fecal incontinence in Madri (Spain). The most common cause for the fecal incontinence was obstetric procedures, idiopathic origin and prior anal surgery, and all these people were refractory to the conservative treatment. The procedure consisted of placing a temporary pulse generator connected to a unilateral electrode at S3 or S4 foramen for 2–4 weeks. After it was confirmed that the SNS was decreasing the incontinence episodes, the patients received the definitive electrode and pulse generator that was implanted in the gluteus or in the abdomen. Two patients did not show improvement in the first step and did not receive the definitive stimulator. Mean follow-up was 17.02 months and during this time the patients showed improvement in the voluntary contraction pressure and reduction of incontinence episodes. Complications were two cases of infection, two cases with pain and one broken electrode. Therefore, although the reason the SNS is effective is unknown, this procedure had satisfactory results in these clinical cases with a low incidence of complications, and the study concluded that it was a good option for treatment of anal incontinence. [3]

Limited evidence from a Cochrane review of randomised controlled trials suggests that sacral nerve stimulation may help to reduce fecal incontinence. [4]

Method

TENS (transcutaneous electrical nerve stimulation) was patented and first used in 1974 for pain relief. TENS is non-invasive; it sends electric current through electrodes placed directly on the skin. Although predominantly carried out as a percutaneous procedure, it is possible to apply sacral nerve stimulation with the use of these external electrodes. It is not known if TENS helps with chronic pain in people with fibromyalgia [5] or neuropathic pain. [6] There are currently no studies into the efficacy of this on an overactive bladder and other associated symptoms of urinary incontinence, however, in a report carried out by GUT (an international peer-reviewed journal for health professionals and researchers in gastroenterology and hepatology) it was found that 20% of the group tested achieved complete continence. All others saw a significant reduction in the frequency of FI episodes and an improvement in the ability to defer defecation. [7]

The first percutaneous sacral nerve stimulation study was performed in 1988. By penetrating the skin, sacral nerve stimulation aims to give a direct and localized electric current to specific nerves in order to elicit a favored response. Today it is one of the most common neuromodulation techniques.[ citation needed ]

Percutaneous procedure

Patients interested in getting a sacral nerve stimulator implanted in them because less severe methods have failed all must go through a trial for their own safety, known as the PNE (percutaneous nerve evaluation). PNE involves inserting a temporary electrode to the left or right of the S3 posterior foramen. This electrode is connected to an external pulse generator, which generates a signal for 3–5 days. If this neuromodulation has positive results for the patient, the option of implanting a permanent electrode for permanent sacral neuromodulation is possible.

The procedure has low level of invasiveness, as all incisions are relatively small. A pulse generator is implanted in a subcutaneous pocket in the upper, outer quadrant of the buttock or even the lower abdomen. The generator is attached to a thin lead wire with a small electrode tip which is anchored near the sacral nerve.

The most common postoperative complaints are pain and lead migration. In most studies, usually 5-10% of subjects need post-operative correction to lead migration, but since leads can be anchored near the sacral nerve, subsequent operations are generally unnecessary.

Mechanism

Stimulation of the sacral nerve causes contraction of external sphincter and pelvic floor muscle, which in turn causes the inhibition of bladder contractions which may be involuntarily releasing urine. Researchers currently believe that the sacral neuromodulation blocks the c-afferent fibers, which are a critical part of the afferent limb of a pathological reflex arc believed to be responsible for incontinence.

See also

Related Research Articles

<span class="mw-page-title-main">Interstitial cystitis</span> Medical condition

Interstitial cystitis (IC), a type of bladder pain syndrome (BPS), is chronic pain in the bladder and pelvic floor of unknown cause. It is the urologic chronic pelvic pain syndrome of women. Symptoms include feeling the need to urinate right away, needing to urinate often, and pain with sex. IC/BPS is associated with depression and lower quality of life. Many of those affected also have irritable bowel syndrome and fibromyalgia.

<span class="mw-page-title-main">Urinary incontinence</span> Uncontrolled leakage of urine

Urinary incontinence (UI), also known as involuntary urination, is any uncontrolled leakage of urine. It is a common and distressing problem, which may have a large impact on quality of life. It has been identified as an important issue in geriatric health care. The term enuresis is often used to refer to urinary incontinence primarily in children, such as nocturnal enuresis. UI is an example of a stigmatized medical condition, which creates barriers to successful management and makes the problem worse. People may be too embarrassed to seek medical help, and attempt to self-manage the symptom in secrecy from others.

<span class="mw-page-title-main">Fecal incontinence</span> Inability to refrain from defecation

Fecal incontinence (FI), or in some forms, encopresis, is a lack of control over defecation, leading to involuntary loss of bowel contents, both liquid stool elements and mucus, or solid feces. When this loss includes flatus (gas), it is referred to as anal incontinence. FI is a sign or a symptom, not a diagnosis. Incontinence can result from different causes and might occur with either constipation or diarrhea. Continence is maintained by several interrelated factors, including the anal sampling mechanism, and incontinence usually results from a deficiency of multiple mechanisms. The most common causes are thought to be immediate or delayed damage from childbirth, complications from prior anorectal surgery, altered bowel habits. An estimated 2.2% of community-dwelling adults are affected. However, reported prevalence figures vary. A prevalence of 8.39% among non-institutionalized U.S adults between 2005 and 2010 has been reported, and among institutionalized elders figures come close to 50%.

<span class="mw-page-title-main">Transcutaneous electrical nerve stimulation</span> Therapeutic technique

A transcutaneous electrical nerve stimulation is a device that produces mild electric current to stimulate the nerves for therapeutic purposes. TENS, by definition, covers the complete range of transcutaneously applied currents used for nerve excitation, but the term is often used with a more restrictive intent—namely, to describe the kind of pulses produced by portable stimulators used to reduce pain. The unit is usually connected to the skin using two or more electrodes which are typically conductive gel pads. A typical battery-operated TENS unit is able to modulate pulse width, frequency, and intensity. Generally, TENS is applied at high frequency (>50 Hz) with an intensity below motor contraction or low frequency (<10 Hz) with an intensity that produces motor contraction. More recently, many TENS units use a mixed frequency mode which alleviates tolerance to repeated use. Intensity of stimulation should be strong but comfortable with greater intensities, regardless of frequency, producing the greatest analgesia. While the use of TENS has proved effective in clinical studies, there is controversy over which conditions the device should be used to treat.

<span class="mw-page-title-main">Functional electrical stimulation</span> Technique that uses low-energy electrical pulses

Functional electrical stimulation (FES) is a technique that uses low-energy electrical pulses to artificially generate body movements in individuals who have been paralyzed due to injury to the central nervous system. More specifically, FES can be used to generate muscle contraction in otherwise paralyzed limbs to produce functions such as grasping, walking, bladder voiding and standing. This technology was originally used to develop neuroprostheses that were implemented to permanently substitute impaired functions in individuals with spinal cord injury (SCI), head injury, stroke and other neurological disorders. In other words, a person would use the device each time he or she wanted to generate a desired function. FES is sometimes also referred to as neuromuscular electrical stimulation (NMES).

Neuroprosthetics is a discipline related to neuroscience and biomedical engineering concerned with developing neural prostheses. They are sometimes contrasted with a brain–computer interface, which connects the brain to a computer rather than a device meant to replace missing biological functionality.

Percutaneous tibial nerve stimulation (PTNS), also referred to as posterior tibial nerve stimulation, is the least invasive form of neuromodulation used to treat overactive bladder (OAB) and the associated symptoms of urinary urgency, urinary frequency and urge incontinence. These urinary symptoms may also occur with interstitial cystitis and following a radical prostatectomy. Outside the United States, PTNS is also used to treat fecal incontinence.

<span class="mw-page-title-main">Spinal cord stimulator</span> SCS TREATMENT

A spinal cord stimulator (SCS) or dorsal column stimulator (DCS) is a type of implantable neuromodulation device that is used to send electrical signals to select areas of the spinal cord for the treatment of certain pain conditions. SCS is a consideration for people who have a pain condition that has not responded to more conservative therapy. There are also spinal cord stimulators under research and development that could enable patients with spinal cord injury to walk again via epidural electrical stimulation (EES).

<span class="mw-page-title-main">Neurogenic bladder dysfunction</span> Bladder disorder due to disease or injury of the nervous system

Neurogenic bladder dysfunction, often called by the shortened term neurogenic bladder, refers to urinary bladder problems due to disease or injury of the central nervous system or peripheral nerves involved in the control of urination. There are multiple types of neurogenic bladder depending on the underlying cause and the symptoms. Symptoms include overactive bladder, urinary urgency, frequency, incontinence or difficulty passing urine. A range of diseases or conditions can cause neurogenic bladder including spinal cord injury, multiple sclerosis, stroke, brain injury, spina bifida, peripheral nerve damage, Parkinson's disease, multiple system atrophy or other neurodegenerative diseases. Neurogenic bladder can be diagnosed through a history and physical as well as imaging and more specialized testing. In addition to symptomatic treatment, treatment depends on the nature of the underlying disease and can be managed with behavioral changes, medications, surgeries, or other procedures. The symptoms of neurogenic bladder, especially incontinence, can severely degrade a person's quality of life.

<span class="mw-page-title-main">Overactive bladder</span> Condition where a person has a frequent need to urinate

Overactive bladder (OAB) is a common condition where there is a frequent feeling of needing to urinate to a degree that it negatively affects a person's life. The frequent need to urinate may occur during the day, at night, or both. Loss of bladder control may occur with this condition. This condition is also sometimes characterized by a sudden and involuntary contraction of the bladder muscles, in response to excitement or anticipation. This in turn leads to a frequent and urgent need to urinate.

A sacral anterior root stimulator is an implantable medical device enabling patients with a spinal cord lesion to empty their bladders.

<span class="mw-page-title-main">Sacral nerve stimulator</span>

A sacral nerve stimulator is a small device usually implanted in the buttocks of people who have problems with bladder and/or bowel control. This device is implanted in the buttock and connected to the sacral nerve S3 by a wire. The device uses sacral nerve stimulation to stop urges to defecate and urinate by sending signals to the sacral nerve. The patient is able to control their bladder and/or bowel via an external device similar to a remote control.

Urogynecology or urogynaecology is a surgical sub-specialty of urology and gynecology.

Electroanalgesia is a form of analgesia, or pain relief, that uses electricity to ease pain. Electrical devices can be internal or external, at the site of pain (local) or delocalized throughout the whole body. It works by interfering with the electric currents of pain signals, inhibiting them from reaching the brain and inducing a response; different from traditional analgesics, such as opiates which mimic natural endorphins and NSAIDs that help relieve inflammation and stop pain at the source. Electroanalgesia has a lower addictive potential and poses less health threats to the general public, but can cause serious health problems, even death, in people with other electrical devices such as pacemakers or internal hearing aids, or with heart problems.

<span class="mw-page-title-main">Overflow incontinence</span> Medical condition

Overflow incontinence is a concept of urinary incontinence, characterized by the involuntary release of urine from an overfull urinary bladder, often in the absence of any urge to urinate. This condition occurs in people who have a blockage of the bladder outlet, or when the muscle that expels urine from the bladder is too weak to empty the bladder normally. Overflow incontinence may also be a side effect of certain medications.

Neurostimulation is the purposeful modulation of the nervous system's activity using invasive or non-invasive means. Neurostimulation usually refers to the electromagnetic approaches to neuromodulation.

In fecal incontinence (FI), surgery may be carried out if conservative measures alone are not sufficient to control symptoms. There are many surgical options described for FI, and they can be considered in 4 general groups.

Neuromodulation is "the alteration of nerve activity through targeted delivery of a stimulus, such as electrical stimulation or chemical agents, to specific neurological sites in the body". It is carried out to normalize – or modulate – nervous tissue function. Neuromodulation is an evolving therapy that can involve a range of electromagnetic stimuli such as a magnetic field (rTMS), an electric current, or a drug instilled directly in the subdural space. Emerging applications involve targeted introduction of genes or gene regulators and light (optogenetics), and by 2014, these had been at minimum demonstrated in mammalian models, or first-in-human data had been acquired. The most clinical experience has been with electrical stimulation.

<span class="mw-page-title-main">Lumbar anterior root stimulator</span> Neuroprosthesis

A lumbar anterior root stimulator is a type of neuroprosthesis used in patients with a spinal cord injury or to treat some forms of chronic spinal pain. More specifically, the root stimulator can be used in patients who have lost proper bowel function due to damaged neurons related to gastrointestinal control and potentially allow paraplegics to exercise otherwise paralyzed leg muscles.

Fowler's syndrome is a rare disorder in which the urethral sphincter fails to relax to allow urine to be passed normally in younger women with abnormal electromyographic activity detected.

References

  1. Hubsher C.P.; Jansen R.; Riggs D.R.; Jackson B.J.; Zaslau S. (2012). "Sacral nerve stimulation for neuromodulation of the lower urinary tract" (PDF). Can J Urol. 19 (5): 6480–4. PMID   23040633.
  2. Hayden DM, Weiss EG (2011). "Fecal incontinence: etiology, evaluation, and treatment". Clin Colon Rectal Surg. 24 (1): 64–70. doi:10.1055/s-0031-1272825. PMC   3140335 . PMID   22379407.
  3. Pascual I, González-Gómez CC, Ortega R, Jiménez-Toscano M, Marijuán JL, Lomas-Espadas M, Fernández-Cebrián JM, García-Olmo D, Pascual-Montero JM (2011). "Sacral Nerve Stimulation for fecal incontinence". Rev Esp Enferm Dig. 103 (7): 355–359. doi: 10.4321/s1130-01082011000700004 . PMID   21770681.
  4. Thaha, MA; Abukar, AA; Thin, NN; Ramsanahie, A; Knowles, CH (24 August 2015). "Sacral nerve stimulation for faecal incontinence and constipation in adults". The Cochrane Database of Systematic Reviews. 2015 (8): CD004464. doi:10.1002/14651858.CD004464.pub3. PMC   9208727 . PMID   26299888.
  5. Johnson, MI; Claydon, LS; Herbison, GP; Jones, G; Paley, CA (9 October 2017). "Transcutaneous electrical nerve stimulation (TENS) for fibromyalgia in adults". The Cochrane Database of Systematic Reviews. 2017 (10): CD012172. doi:10.1002/14651858.CD012172.pub2. PMC   6485914 . PMID   28990665.
  6. Gibson, W; Wand, BM; O'Connell, NE (14 September 2017). "Transcutaneous electrical nerve stimulation (TENS) for neuropathic pain in adults". The Cochrane Database of Systematic Reviews. 9 (3): CD011976. doi:10.1002/14651858.CD011976.pub2. PMC   6426434 . PMID   28905362.
  7. G Thomas; C Norton; R J Nicholls; C Vaizey (2013). "OC-088Prospective Pilot Study to Investigate Transcutaneous Sacral Nerve Stimulation for Faecal Incontinence". Gut. 62: A38. doi: 10.1136/gutjnl-2013-304907.087 .

Bibliography