Trial Wire SNS
nerve stimulation (SNS) is used as a treatment for certain patients with faecal incontinence. Patients most likely
to benefit are those with intact muscles that do not work very well, though
sometimes patients with damaged muscles benefit. It is occasionally used for
patients with constipation. It involves low-level
electrical stimulation applied via electrodes through the sacral foramina to
the sacral nerve supply of the lower bowel and sphincters. Shortly after
surgery continuous stimulation begins. The patient interrupts the pulse
for defaecation and voiding, using an external magnet.
other tests are necessary before the procedure?
simple tests are required to identify you as a possible candidate likely to
derive benefit from the procedure. These tests include anorectal physiology and endoanal
ultrasound to rule out sphincter injury, defecating proctography (to rule out
prolapse) and transit studies. One
of the problems with SNS is that we don’t know exactly how it works and it is
for this reason that it doesn’t always work even when a temporary wire has been
the procedure involve?
wire is inserted in a day case or outpatient setting under a local anaesthetic
(an injection to numb the skin). A fine needle is passed through the skin of
the buttock with you lying on your front. The surgeon will then establish where
the nerves supplying the anal sphincter are located by passing a very low power
electrical current down the needle. The needle is then switched for a flexible
wire, which is taped to the buttock skin. The other end of this wire is then
connected to a stimulator, which is the size of a small iPOD, worn by the
patient on their belt. As the test
wire and battery are not covered by dressings during the test period you must
not bath or shower. You can drive
if you disconnect the wire from the stimulator. The test period lasts for two weeks. The wire is removed very easily.
What is the recovery like after surgery?
be able to walk out of the consultation room after the procedure with usually
only minor discomfort. You will be asked to keep a diary of your bowel control
and episodes of incontinence. If your control is improved with the wire in
place, then we may recommend considering implantation of a permanent implant.
Approximately two thirds of patients having a temporary wire proceed to a
permanent implant. It is important
NOT to tell lies in the diary i.e., if the test doesn’t work, a permanent
implant will be a waste of time.