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Sacral Neuromodulation


Sacral neuromodulation (SNM) is a procedure whereby a lead is implanted through back and into the pelvis near the nerves that affect the function of the bladder to bring about a change in the way the bladder behaves. The lead is connected to a stimulator which is placed underneath the tissues at the top of the buttock. This stimulator works to modulate abnormal signals coming from the bladder to the brain and this then provides relief of the patient’s symptoms.


Sacral neuromodulation is used as third line therapy for those with an overactive bladder.

Preoperative Instructions

All patients are given full instructions on how to prepare for the procedure well ahead of the day of surgery. In most cases the following preparation is required:

  • Inform the surgical team of what medications you are currently taking and follow any guidelines given by the team, especially regarding blood thinning medication.
  • If any symptoms of illness occur before the procedure (e.g. cold or fever) inform the surgical team.


Sacral neuromodulation is typically performed as a two-stage process. First a lead is implanted and connected to a temporary stimulator device that is worn on a belt. Over a 1-2 two-week period a number of programs are tested to ensure the patient receives adequate relief of their symptoms. If during this trial period the desired improvement in the patient’s symptoms are obtained, the patient then proceeds to stage two of the procedure whereby the stimulator in implanted under the skin at the top of the buttock. Sacral neuromodulation stage one is typically performed as a day case procedure under general anaesthetic. Stage two is also a day case procedure and can be performed under local anaesthetic only or with general anaesthesia.

Postoperative Instructions

After the procedure a large dressing in placed over the site where the leads exit from the back to the temporary stimulator. This dressing must remain in take and should not get wet during the trial period. Patients are provided with the additional following advice at the time of discharge:

  • Inform all Healthcare professionals that you have an implanted neurostimulation system.
  • Avoid physical activities that may damage the implant site or the implanted neurostimulator or dislodge parts of the system
  • Restrict activities such as stretching and lifting heavy objects, for a period of time following surgery to minimise the possibility of lead displacement.
  • Consult your surgeon if any unusual signs or symptoms develop.
  • Carry the Medtronic patient identification card and patient programmer with them at all times.
  • Consult the InterStim Patient Therapy Guide for answers to questions about how the sacral neuromodulation may affect their day-to-day life.


The risks of sacral neuromodulation include:

  • Pain at the implant site.
  • Lead migration.
  • Infection.
  • Technical or device problems.
  • Adverse changes in bowel or bladder function.
  • Undesirable stimulation or sensations.

Treatment Alternatives

Sacral neuromodulation is an alternative third line therapy for the management of overactive bladder.

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