Colic: when surgery is needed

[dropcap]I[/dropcap]n previous articles, we discussed colic as an umbrella term for ‘abdominal pain in the equine’ and looked at some of the many causes of this all too common condition.

Regardless of the cause of the colic, however, the fact remains that if your vet has exhausted all forms of medical management, you will be advised to get your horse to the nearest surgical facility for intensive monitoring, treatment and potentially surgery. Research has shown that colic type, the time since the onset of the colic, and the horse’s condition on admission are crucial factors in the success rate of surgery. In other words, the faster you can get your horse to surgery, the greater his chance of survival.

At the hospital

Some horses arrive at the hospital and due to the severity of their condition are taken straight to the theatre. Others will have further tests done to establish that surgery is the best way forward.

The first of these tests is usually the abdominal ultrasound. This allows the surgeon to evaluate the small and large intestine, and because an ultrasound is done in real-time, it can also allow observation of the motility of the gut.

A further test that may be performed is an ‘abdominal tap’. This involves obtaining a sample of peritoneal fluid (the fluid in the abdomen surrounding the intestine) from the horse to check for elevated protein and white cell levels. In a normal horse, one would expect to see a clear amber fluid, but in sick horses, the colour can become cloudy, tinged with red, or if the intestine has perforated, the fluid may be green with visible food particles.

If an intestinal stone is suspected, an abdominal x-ray may be performed to visualise the stone.

At this stage the clinical state of the horse will be assessed in the context of the results of the tests. There are three possible outcomes:

1. Surgery is recommended.
2. The horse continues to be observed at the facility and medical management continues. Surgery may be required or the horse may be able to go home.
3. The horse may be euthanised if the assessment reveals that the intestine is severely compromised, the horse is too unstable or the horse has comorbidities that make him a poor candidate for surgery.

Going into surgery

The surgery itself involves putting the horse under general anaesthetic, getting him onto the surgical table and opening up his abdomen. The incision is usually made down the midline of the abdomen. The surgeon will then reach into the abdomen to assess the problem. The treatment depends on the diagnosis made at this stage. It could involve the repositioning of displaced intestine, the removal of damaged intestine, the clearing of a blockage of feed, sand or a foreign object, or any other necessary procedure.

During the operation, the surgeon will gain information that will allow him to give a more accurate assessment of the likely prognosis. In some cases, the surgeon may advise that the horse be put down on the table as the damage seen internally is more advanced than was originally suspected. Alternatively, the surgeon may find that the case is reasonably straightforward and needs little intervention, leading to the anticipation of a smooth post-operative recovery.

Surgical time is usually somewhere between two and four hours.

Recovery and potential complications

Colic is only the first part of the process. Careful post-operative monitoring is vital to identify and treat complications that may occur following surgery, which unfortunately are not uncommon in horses. An individual treatment plan is created for each horse, which specifies factors such as nutrition, fluid therapy, ongoing tests, pain relief, antibiotic treatment and follow-up.

The first 72 hours post-operatively are the most critical. This is when the intestine tries to reorganise and recoordinate itself after being manipulated and cut.

There are several potential complications:

• One of these is ileus, where the gut stops moving as a consequence of being manipulated. This is very painful for the horse, and may take some time to resolve.
• If the circulation to the intestine was cut off for too long in certain areas, the wall of the intestine may become inflamed, infected, or die.
• If the gut was rejoined after a segment was removed, the new join can fail due to a blockage or rupture. A rupture can lead to peritonitis and overwhelming sepsis.
• The immune system may be affected by the surgery and infection is a concern.

After the first 72 hours other post-operative complications may start to feature:

• Scar tissue formation, adhesions and intestinal narrowing may cause further colics.
• Persistent diarrhoea from infections, disruption of the microflora of the gut or inflammation of the wall of the gut is a possibility.
• Hernias and infections along the wound line are also not uncommon.

Life after colic surgery

With the improved surgical techniques, the majority of horses will go home after colic surgery and make a full recovery. On average horses will require at least 90 days to recover from surgery of this type. The first 30 days are typically box rest and hand walking, which allows the incision and intestines to heal. The second 30 days involve limited turnout in a small paddock. The final 30 days often involve very light work. After this time, riding can commence again.

If surgery is successful, and the post-operative period is uneventful, there is no reason why horses cannot resume their previous level of work, whether that be as a companion pony or performance horse on the international circuit.

 

The full article appears in the September issue of HQ (114). 

Text: Dr Lizzie Harrison