The Findon Vet Surgery has provided the top level of dog perineal hernia repair surgery in Adelaide for over 20 years. Both the internal Obturator muscle flap and the Semitendinosus muscle flap techniques are performed by Dr Ian Hogben.
Scroll down for photos of Diesel's perineal hernia surgery using a muscle flap from inside the pelvis! Beware - photos are graphic in nature!
This would have to be one of the most uncomfortable conditions and is the result of on-going straining to poo. It almost always occurs in entire (un-desexed) male dogs and this is because their prostate gland is overly large, causing constipation and straining. Some breeds develop perineal hernias more often than others, notably: Boston Terriers, Boxers, Welsh Corgis, Pekingese, Collies, Dacshund, Old English Sheep Dogs, Kelpies and Kelpie crosses. But all breeds are susceptible and we have seen them in Blue Heelers and Heeler crosses, Chihuahuas, Border Collies and crosses, Fox Terriers, Beagles, Bull Terriers and crosses, and a Papillon.
The prostate gland usually sits on floor of the pelvis,
right under the rectum and lower colon. Many enlarged prostate glands
become soooo big they are forced out of the pelvic region and 'fall'
forward of the front edge of the pelvis into the abdomen. Because the
poo (faeces) passing down the colon has to be squeezed over the large
prostate, the unfortunate dog has to huff and puff a fair bit more to
get it out! In humans the result is more likely to be a case of
The back log of faeces causes constipation, and x-rays of affected dogs show a huge amount trapped in the colon, with the colon stretched in size. Some faeces slowly gets pushed past the prostate and collects in the rectum because it is too large to easily pass out the anus. As more gets forced into the rectum, BEFORE what is already there can be passed out as a stool, the rectum stretches and balloons out to the side. Sometimes a little liquid faeces squeezes past the hard mass of faeces now trapped in the rectum, looking like diarrhoea. This is very painful.
In the X-ray at left, the faeces has backed up all the way to the left hand side of the X-ray in this constipated dog. The anus is to the right hand side. The black arrows point to either side of the colon (large bowel) and the long white-ish tube is the constipated faeces, and the darker area to the left where the faeces extends to (left two arrows), is gas in the stomach which is next to this part of the colon.
The impacted stretched rectum causes the first stage of the swelling of the back end and is called rectal sacculation.
Straining and pain rapidly progress and the pushing and pressure
exerted trying to get the ever increasing mass of faeces out finally
causes damage to the structures around the entrance to the pevic canal,
similar to the pelvic floor muscles in humans, and the organs in the
abdomen now get forced back with the constant straining. The organs
'break through' the barrier at the pelvic canal opening and are pushed
back further still and end up by the anus causing a much larger perineal
swelling to one side of the anus.
1) This is Diesel AFTER having an enema to remove impacted faeces. There is still significant swelling to the right of his anus.
2) After making the incision, the first thing noted is Omentum which has herniated backwards from the abdomen.
3) During the repair process, sutures are 'Pre-placed' before tieing to ensure an even spread of well positioned sutures. The first three are shown.
In some dogs it happens to BOTH (bilateral) sides. Possibly 33% of those we have seen have had bilateral perineal hernias!
The swelling at the dog's back end now contains either intestines, the bladder (with the urethra bent back on itself), omentum (the net like webbing in the abdomen) and/or the enlarged prostate.
We have seen an abscessed prostate in the hernia, and also a large
prostatic cyst. Also there is damage to these organs and tissues and a
lot of tissue fluid that oozes from traumatised tissues collects in the
area. It is quite a mess and presents a major surgical challenge. Note
Diesel's Omentum is thick/swollen and abnormal after having been forced
back under pressure and then trapped in the hernial sac.
For many years, simple internal suturing together of the structures
around the perineum was performed. This technique was superceded by a
vastly superior surgical method utilising muscle flaps to repair the
hernial aperture, the hole that the abdominal organs are forced back
through. Where-as simple suturing the area resulted in almost certain
breakdown and recurrence of the hernia, the new technique is a much
stronger repair and resists breakdown and recurrence much, much better.
The great difference in success rates has deemed the older technique no
longer a surgically accepted practice for this problem for the past 12
or so years. Our surgeries have only ever performed the more recent,
currently accepted, muscle flap techniques since the early 1990's.
Occasionally a more recent technique using one of the muscles of the
back of the thigh is required. Our surgery was the very first in South
Australia to perform this surgery in July 2000, and the interstate
Surgery Specialist who sent me the published information on the first 5
cases in the USA (there were no Animal Surgery Specialists in Adelaide
at that time) actually believed it to be the first time in Australia!
For Diesel, we used the Internal Obturator muscle,
which is found on the floor of the pelvis and attached to the top of
the femur, behind the ball joint, its function is to rotate the leg
outwards from the hip. By using this muscle, we must sacrifice this
function! Luckily it is not a major issue as the other muscles are used
to lift the leg outwards for, say, cocking the leg to urinate.
1) All of the internal sutures have been placed and the wound edges are sitting nicely together.
2) A dog's bottomis NEVER a pretty site! But a damn sight better without the swelling from the hernia 🙂 Note the inter-locking skin suture pattern which places an even pressure on the wound edges... and have less irritating loose ends!
3) Ready to go home and no more straining and constipation...and no more distress and pain.
This surgery is quite complex and much of it must be done by feel as
the surgeon cannot see much inside the perineal region. It is like
working inside a small cave with all of the structures around it
collapsing inwards to block your view of the surgical site. There are MANY important structures in the area that must not be damaged.
To do so would cause paralysis of the whole leg, or loss of function of
the anal muscles (causing faecal incontinence), or fatal bleeding, or a
perforated rectum (causing pertonitis, perineal abscessation,
septicaemia). We have have not encounted ANY of these complications in
all of the surgeries we have performed on perineal hernias.
This is why it is imperative that the surgery be performed by a competent surgeon who has had experience with this surgery.
Here is Diesel with his Dad, waiting for his sutures to be removed ..... and looking happy with himself, although a little apprehensive!
Immediately after the surgery Diesel could pass his stools normally, with minimal discomfort - NO MORE STRAINING!
The ' walls ' of his rectum were firm, with no bulging
(saccu-lation), and there was definately no more constipation. Diesel
was castrated at the same time as his hernia repair, and this rapidly
reduced the size of his troublesome prostate which had caused his
constipation and straining initially.
Diesel continues to do really well and is able to race about normally
again. The only real risk to the surgery site is if he becomes severely
constipated and his straining breaks down the hernia repair.
I saw this once in a dog who'd had a bilateral hernia repaired and 2 years later, when the owners left him in the care of a firend (who wasn't really a 'dog person'), was fed on a diet of raw bones EVERY day, became constipated and was left like this until the owner came home weeks later. His agony and straining did cause a breakdown - and this was the first dog to have the back leg muscle used for his repairs! And he never suffered a problem in the back end again.
to end on a photo like this, BUT it shows a well healed surgery that,
despite the surgery involving a 'dirty' area, did not become infected.
There is no swelling remaining... a great outcome for Diesel!
Diesel continues to do well ...
As an after thought, I have added a photo of another dog who's perineal hernia was not repaired early and continued to swell in size until its bladder AND a lot of intestines ended up in the hernia! Note that his anus has been pushed right up high to the right hand side. The perineal hernia repair we performed on a dog immediately prior to Diesel's was nearly THIS SIZE! Unfortunately I didn't think to take a photo! Its surgery also went very well and he has had no problems since.