06 Sacral
Neuromodulation

Over the years many different attempts have been made to try and stop the abnormal sphincter activity but the only thing that has been found to restore voiding is sacral neuromodulation (SNS). This is quite an involved and expensive procedure. Please follow this link to learn more about Medtronic stimulators and what is involved in having one inserted.

SNS is a procedure which is done in two stages. The first stage is usually done under a short general anaesthetic and a stimulating lead is inserted through a naturally occurring hole in the sacrum “the third sacral foramen”or “S3” as it is commonly known.

Sacral Neuromodulation

The stimulating lead is a sophisticated device with “tines” on it which prevent it coming out and 4 different points through which can be activated to stimulate through.

Sacral Neuromodulation

On waking following this “stage 1” procedure the lead is connected to an external stimulating battery and a trial period begins to see to what extent stimulation improves voiding difficulties. The lead can be “programmed” with an external device so that the stimulation can be applied by the best positioned two leads. This lead is going to be lying in nerves called the “pre-sacral plexus” in a somewhat unpredictable way and depending very much on your anatomy and your arrangements of nerves – something that there is no way of knowing – one combination of stimulating electrodes may work better than another.

After programming, the battery remains on and the lead is left in place. After some weeks (between 4-12) you will be reviewed and if you are able to pass urine again, you will be put on the operating list for the “second stage” or “stage 2”.

At stage 2 (in the UK also done under general anaesthetic) a complex and sophisticated permanent stimulating battery is implanted in your body and connected to the lead already in place. This same stimulator is used in a wide range of other neurological conditions including deep brain stimulation, and is not dissimilar to a cardiac pacemaker.

Sacral Neuromodulation

On waking and recovery the stimulator is programmed and the majority of patients get the same response as they did with the temporary external stimulator.

All this sounds very straight forward but as your surgeon will explain before the procedure, there can be complications. I have always said to patients having a stimulator – it is not a “quick fix” and a recent study of 44 patients with Fowler’s syndrome found that although the majority were helped by this intervention. However about 45% of them needed revision surgery for problems such as because of leg pain, battery pain, lead displacement, lead fracture, loss of efficacy or battery site infection, particularly if they not follow their surgical teams’ advice.