What is Sacral Nerve Root Stimulation

09 Nov What is Sacral Nerve Root Stimulation

Permanent electrical stimulation of sacral nerve roots was first used in the 1970s to treat neurogenic urinary problems. Over the last few decades, sacral nerve root stimulation is being used for coccydynia, chronic pelvic pain, interstitial cystitis, lower urinary tract dysfunction, and very low back pain.

How does sacral nerve root stimulation work?

Electrical current is applied by placing an electrode attached to a pulse generator, against one of the sacral nerve roots. The voltage ranges from 0.5 to 3 volts with a frequency of around 15 Hz. The effect is cause by direct stimulation of the urethral sphincter, bladder muscle, and anal sphincter via motor nerves. In addition, electrical stimulation causes complex modulation of sensory, motor, and autonomous nerve paths both in the peripheral and central nervous systems.

How is the sacral nerve stimulation done?

Before the permanent stimulator generator is surgically implanted, a peripheral nerve evaluation test (PNE) is performed. This involves insertion use of general anesthesia or sedation. Several sacral foramina are cannulated (usually the 3^rd and 4^th). When the cannula is inserted through the sacral foramen (opening), the tip will be positioned adjacent to the corresponding nerve root. With the PNE test, a stimulator is worn outside the body. When the actual implantation occurs, the device is surgically implanted beneath the skin.

Most stimulators last for up to 10 years. The stimulator is implanted beneath the skin of the left or right buttock. Patients are given a remote control device that allows them to turn the device off or on, switch between several stimulation programs, and change the voltage.

Who is a candidate for sacral nerve stimulation?

Patients cannot have the surgery if the skin has an infection, or if the patient has a chronic immune disease that weakens the immune system. Patients must be motivated for the sacral nerve stimulation surgery, and should be able to handle the remote control device. In addition, patients who need surgery of the pelvic floor region or a MRI scan may not be suitable candidates for this treatment.

Does sacral nerve stimulation work?

In a recent clinical study, researchers evaluated sacral nerve root stimulation for relief of pain. Five patients, who had not responded to surgery, conservative treatment, or spinal cord stimulation, had a 7-day trial of sacral nerve root neuromodulation. The researchers found that paresthesia coverage was 75% or higher for all patients. Overall, visual analog pain scores decreased by an average of 9 points, and all patients reported improvement with the therapy. It was concluded that sacral nerve stimulation was successful for pain relief.

In another study, researchers evaluated sacral neuromodulation for the treatment of chronic pelvic pain, interstitial cystitis, and painful bladder syndrome. In the study 12 female and 9 male patients with severe pain had treatment. On average, the patients had a 42% improvement of symptoms, with 77% reporting a successful trial stimulation.

What should I expect after the procedure?

After your surgical implantation of the sacral nerve stimulator, the incision area will feel sore for a few days. As the incision heels, this will improve. You must avoid soaking in a tub or pool until incisions heal, and should not do any heavy lifting or bending for a few days.

Will the battery need to be replaced?

The battery lasts 3-5 years, and this depends on the strength of the signal used to control symptoms and the amount of use each day. When the battery is replaced, the entire neurostimulator is replaced also.

Resources

Alo KM, Yland MJ, Redko V, et al. (2013). Lumbar and Sacral Nerve Root Stimulation (NRS) in the Treatment of Chronic Pain: A Novel Anatomic Approach and Neuro Stimulation Technique. Neuromodulation.

Feler, C; Whitworth, L; Fernandez, J. Sacral Neuromodulation for Chronic Pain Conditions. Anesthesiology Clin N Am. 2003. 21: 785– 795. 4) Jain, N; Jain, A. The Management of Intractable Low Back Pain: Recent Advances. JIMSA. 2013; 26, 4: 245-247.

Hunter, C; Dave, N; Diwan, S; Deer, T. Neuromodulation of Pelvic Visceral Pain: Review of the Literature and Case Series of Potential Novel Targets for Treatment. Pain Practice. 2013; 13, 1: 3–17.

Patijn, J; Janssen, M; Hayek, S; Mekhail, N; Van Zundert, J; Van Kleef, M. Coccygodynia. Pain Practice. 2010; 10,6: 554–559.

Zabihi N, Mourzinos A, Maher MG, et al. (2008). Short-term results of bilateral S2-S4 sacral neuromodulation for the treatment of refractory interstitial cystitis, painful bladder syndrome, and chronic pelvic pain. Inter Urogynecol Jour, 19(4), 553-447.