is a tunnel that starts inside the anal canal, traverses (travels across)
the anal sphincter muscle (which controls fecal continence), and exits
onto the skin, just outside the anus. The underlying cause is most often
from a perianal abscess (see our complete discussion on perianal abscesses)
or less often from Crohn’s Disease, or OB trauma. Perianal abscesses
typically begin as an infection of an anal gland located at the junction
of the anus with the rectum. The infection can progress and result in
an abscess located under the skin around the anus. These will either drain
spontaneously or require surgical drainage. About 30-50% of the time the
anal gland responsible for the infection will stay open (internal opening).
This allows bacteria to accumulate which will then reform an abscess or
drain through the opening in the skin around the anus (external opening).
are easily diagnosed. Symptoms can be recurrent abscesses, recurrent drainage
from one area, or persistent drainage from an area near the anus. On exam,
we will see an opening in the skin around the anus (external opening).
Occasionally, the tunnel itself can be felt through the overlying skin.
While looking into the anal canal, we may be able to see an abnormal appearing
anal gland (internal opening). At times, the internal opening is difficult
to find in the office and may require an examination under anesthesia.
classified according to the amount of anal sphincter muscle the tunnel
traverses. Fortunately, the great majority of fistulas involve only the
lower end of the sphincter muscle, therefore involving only a small amount
of the sphincter muscle (low inter or transphinteric fistula). This is
of primary importance because the sphincter muscle is responsible for
control of defecation so therefore it is important not to cut too much
muscle or leakage or incontinence could occur. Because of this it is important
that you work with a board certified colon and rectal surgeon who has
significant experience in solving this type of problem.
This means to open the tunnel from the internal opening to the external
opening. By doing this we eliminate the internal opening and open the
tunnel for drainage. This allows your body to heal the fistula tract
by removing both the source of the infection (internal opening) and
the tunnel that allows bacteria to collect and grow. This procedure
can be performed when the amount of sphincter muscle involved is small.
This is usually performed as an outpatient procedure under local anesthesia
with intravenous sedation. For more complex fistulas, other surgical
techniques may need to be employed. (see below)
This is a heavy suture or a latex loop that enters the internal opening
and exits the external opening and is tied as a loop. This is used to
both stop abscesses from recurring by keeping the tunnel open on both
sides, as well as slowly cutting through the muscle in cases where too
much muscle is involved by the fistula to cut through at one time. This
is typically reserved for either complex fistulae or for patients with
multiple fistula due to Crohn's Disease (in this case the seton is kept
in place for drainage, not to cut through the muscle). The seton can
be tightened gently in the office to reduce the amount of muscle involved
in the fistula. Think slow-motion fistulotomy. This is also typically
performed as an outpatient procedure under local anesthesia with intravenous
sedation. In our practice we tend not to use the seton that often for
cutting, because although it works well in preventing incontinence,
it can lead to a "gutter" type defect, leading to some leakage
in the future.
Glue: An alternative to the use of Seton's that we have been
using in the practice for several years is fibrin glue. This situation
occurs when the fistula tract involves an amount of sphincter muscle
that can't be simply divided by fistulotomy, without adverse consequences.
The fistula tract is initially scrapped to allow the glue to become
adherent to the wall. The "glue" is then injected into the
tunnel and the internal opening is closed. Your body then incorporates
the glue and seals the tunnel off. The benefit is that no sphincter
is divided (therefore no risk of control problems). The downside is
the success rate is only about 50%. This is performed as an outpatient
procedure under local anesthesia with intravenous sedation.
Advancment Flap: This technique involves raising a portion
of the rectal lining, sliding it over the internal opening and sewing
it in place. This covers the internal opening with healthy tissue and
stops bacteria from entering the tunnel. The fistula tract is scrapped
out and filled with glue or a drain is left in place for 2-4 weeks.
When we sew closed the internal opening and cover it with healthy tissue,
the majority will heal. This procedure is reserved for the most complex
of fistula tracts. This may be performed under local anesthesia with
intravenous sedation or general anesthesia. Hospitalization is usually
in order with a 1-2 day stay.
- For the
simpler fistulas we typically will have our patient take two enemas
prior to the procedure. The first should be administered about 2 hours
prior to leaving for the hospital, and the second is administered about
1 hour prior to leaving for the hospital. It is important to hold the
enema for about 5 minutes.
- For the
complex fistulas that will require an endorectal advancement flap, our
patients will typically undergo a complete bowel prep with a clear liquid
diet for 24 hours prior to the procedure, along with Fleets Phosphosoda®,
and oral antibiotics.