What Is Sacral Neuromodulation (SNM)?
Your sacrum is a lower part of your back. It is connected to your pelvis. Nerves control the muscles in your body by sending signals to and from your brain. The nerves in your pelvic area help you urinate and make bowel movements. If your brain and the nerves in your sacrum (sacral nerves) do not communicate well, your bladder and bowel cannot work like they should.
Sacral neuromodulation (SNM) stimulates the sacral nerves with a small amount of electricity. This helps your brain communicate with your bladder and bowel. It may reduce or stop bladder and bowel control issues.
SNM can treat:
- Urinary retention
- Overactive bladder with or without urgency
- Urinary incontinence
- Anal incontinence or accidental bowel leakage
How SNM works
A surgeon will put a battery-operated device under your skin near the back of your hip. The device is about the size of a stopwatch. It is connected to a wire that your clinician will put near the sacral nerves. The device will send mild electrical signals to the sacral nerves.
You will have a small remote for the stimulator device. You can use the remote to adjust how much stimulation the device is giving. You can also use the remote to turn the device on and off.
The sacral nerve communicates with muscles and smaller nerves that control your urination and bowel movements. It also communicates with your brain.
SNM changes how the sacral nerve works. It also changes the signals that the nerve sends to the brain about bladder and bowel feelings. The electrical pulses from SNM help fix the communication between your sacral nerves and brain.
When to Consider SNM
SNM may be right for you if the following do not help your symptoms:
- Behavior changes
- Diet changes
- Pelvic floor exercises
- A catheter
The SNM Procedure
You will need to fill out a bladder and/or bowel diary before and during the test phase. A member of your care team will give you the diary to fill out.
It is very important that you fill out this diary honestly and completely. The diary will help you and your care team see if SNM is an effective treatment for you.
There are two parts to SNM.
Part 1: Test Stage
This stage helps you and your care team see if the therapy will work for you. This stage comes before the device is implanted. If stimulation helps your symptoms, you may get an implant.
During the procedure, your surgeon will put a lead under your skin near a sacral nerve. A thin wire is attached to the lead. The wire will come out of your body through a small cut in your lower back or upper buttock. The wire is connected to the test stimulator device. You will wear it when you go home.
Your surgeon will determine if you need an office-based outpatient procedure or if you need to go to the operating room.
- For outpatient procedures, your surgeon will use local anesthetic (numbing medication) to numb the area.
- For operating room procedures, you may have an anesthesiologist (a physician trained in pain management) to help you feel comfortable.
Your care team may ask you to describe what you feel when they stimulate the sacral nerve.
- You may feel a pulling, tingling or tapping feeling in your pelvic muscles.
- Your big toe may move.
After the procedure, your clinician will show you how to use the remote to control the stimulator device.
Your care team will give you a bladder and/or bowel diary to track your symptoms during the test stage. Then, you can go home.
Part 2: Implanting the SNM Device
If the test stage goes well, your surgeon will implant the device in an operating room. This typically happens one to two weeks after the test stage.
Your surgeon will make a cut that is about two inches long for the stimulator device. They will attach the device to the wire that was placed during the test stage. At that point, the whole system will be under your skin.
How Long the SNM Device Will Last
The battery in the stimulation device often lasts 15 to 20 years but may last 20 to 25 years.
You will know that the battery is low when the device remote says the battery is low or when your symptoms come back. Your surgeon will put a new battery in when needed.
The wire does not need to be adjusted for most people. Sometimes people fall or have an accident that moves the wire. If this happens, your care team may have to move it back.
All surgeries have risks. Some rare risks include infection, pain, and lead movement.
If you have an SNM device, be careful with MRI (magnetic resonance imaging) studies. Consult the clinician who implanted the device or the device manufacturer if you need to have an MRI.
Many issues with SNM can be addressed by reprogramming the system, medications or surgery. Your surgeon can remove the SNM system at any time.