Current Accepted Surgical Techniques:
- Muscle flap from the pelvic floor (internal obturator muscle flap) perineal hernia repair, complex and requiring advanced surgery. Performed at Findon Vet Surgery since 1994. See Diesel's Perineal Hernia Repair
- Muscle flap from caudal thigh hamstring (semitendinosus muscle flap) perineal hernia repair. Very advanced procedure reserved for patients who have irrepairably damaged a prior obturator procedure. Performed by the Findon Vet Surgery since 2000 and was supposedly the first of this operation performed in Australia.
- NOT acceptable is an old technique that simply places sutures from the sacrotuberous ligament to muscles of the anus. It has an extremly high failure rate.
- Please contact the Findon Vet Surgery if need more information about perineal hernia repair surgery.
A perineal hernia is when the contents of the abdomen herniate (are
pushed through a tear in the peritoneum - the lining of the abdomen)
BACKWARDS through the pelvic canal, and out by the side of the anus! It
sounds aweful, and it certainly is as bad as it sounds.
Before there is an actual perineal hernia, there is constant
straining due to constipation. The most common cause is a chronically
enlarged prostate in and entire older male (un-castrated, un-desexed)
dog which blocks the passage of the stools through the pelvis. The
prostate sits under the lower large bowel (the colon) and rectum, inside
the pelvic canal. Initially this straining causes a lesser problem
called rectal sacculation, and is a bulge in the rectum - a stretching
of the rectum - and this fills with faeces. So much faeces gets trapped
here that it just gets bigger and bigger, with the poor dog straining
more and more as he can't get the stools out.
Eventually this straining is so severe that the pressure in the
abdomen from the poor dog straining is great enough to push organs and
other contents form the abdomen back through the pelvis to end up next
to the swollen rectal sacculation. The only solution is major surgery.
Firstly just the floppy omentum tissue, a web like net structure in the
abdomen, is pushed though a tear in the peritoneum. Then the bladder is
pushed backwards and ends up bulging next to the bottom! In a couple of
dogs I have found intestines, and also one had a large prostatic
The current accepted procedure for repair of a perineal hernia
is a muscle flap utilising the internal obturator muscle from the floor
of the pelvis. This muscle is freed up and isolated from its insertion
on the femur, and then reflected up and used effectively to plug the gap
by suturing it to the strong sacroiliac ligament to the outer top side,
and to the muscles of the anus (the coccygeus,levator anis and anal
An early technique that just uses sutures from the ligament to the
anus muscles has not been recommended for this repair since the 1990's
due to frequent breakdown. I have repaired a few of these over the years
using the obturator muscle flap technique.
If the obturator muscle flap surgery beaksdown, then another muscle
flap from the back of the thigh, the semitendinosus muscle, is reflected
up and uner, and partly around the anus to repair the heria. This was
first performed in Australia by myself around 1999 or 2000 - as advised
by a small animal surgical specialist who sent me the details on the
procedure after it had been performed on five dogs in the USA!
CASTRATION is advised at the time of the perineal hernia repair
surgery. An enlarged prosteat is by far the most common contributing
cause of constipation and desexing an entire undesexed male dog is
necessary to remove the source of testosterone (male sex hormaone) which
stimulates activity in the prostate and its subsequent enlargement.
An enlarged prostate sometimes is the result of prostate cancer, a
prostatic cyst or prostatitis due to infection. Prior to perineal hernia
repair surgery, the prostate must be examined thoroughly and usually
includes a fine needle aspirate biopsy to determine what underlying
prostate disease is present. In the case of a highly malignant prostatic
cancer, repairing the hernia is unlikely to be of benefit - however,
some prostatic cancers resolve due to pathologists being unable to
accurately predict the cancer's growth behaviour as a result of
prostatic cells showing varying characteristics that are almost
impossible to interpret.
Indeed I once had a large entire male rottweiler whose results came
back as a highly malignant prostate cancer. We did not euthanase this
dear old fellow (and he didn't have a perineal hernia - just rectal
sacculation) but instead castrated him and treated him with anti-male
hormaone treatment, and strong antiinflammatory drugs to give him some
comfort and quality of life - which we expected to end in weeks. BUT he
responded magnificently. The tumour shrank withOUT any chemotherapy and
he liver for a few more years without any recurrence of a prostate
problem at all and died at an old age!!!! Thus is the nature of prostate
cancer - unpredictable!
All dogs presenting with a large bulge next to their anus should have
an ultrasound performed to check the contents of the mass, to check if
it is a perineal hernia, a tumour (cancer) or other (abscess or cyst, or