Colic Surgery- to cut or not to cut?

Your worst nightmare- your vet says your horse needs colic surgery.
Here is what you need to know.

 A patient in theatre

Most episodes of colic will resolve with prompt veterinary treatment at the stable yard. Should your vet feel that your horse may need additional treatment and monitoring, they will advise that your horse should be admitted to a hospital facility.

The hospital should have adequate surgical and anaesthetic facilities and an appropriately trained team. There should be capabilities to administer continuous intravenous fluids, have access to ultrasonography and a system in place to monitor the patient – (CCTV cameras are also useful).

Of the horses admitted to a hospital facility, a large proportion will respond favourably to intensive medical treatment and monitoring. This may involve repeated nasogastric tubing, intravenous fluid therapy, pain control, decompression of the intestines (caecal trochar) and the use of drugs like phenylephrine to attempt to correct certain displacements.

Ultrasonography plays a critical role in the monitoring and early diagnosis of intestinal problems that require surgical treatment.

Ultrasound exam of distended (enlarged) small intestines – (this horse underwent colic surgery)

The decision to refer a horse for surgery will depend on a number of factors and this will vary between individual veterinarians. There are the obvious candidates with uncontrollable pain and/or massive gas distention and unrelenting reflux.

For the other colic patients, any deterioration in clinical parameters, worsening of ultrasound exam, increasing reflux, lack of droppings, worsening of rectal exam, recurrent or unresolved pain, or increasing abdominal distention should be an indication that surgery should be considered.

The most important factor in the successful outcome of a colic surgery patient is to recognise the need for timeous surgical treatment. Colic surgery should never be considered as the “last option” therapy.

Horse undergoing colic surgery – Note: The distended small intestine

The incision through the mid-line.

Your horse has an excellent chance of surviving colic surgery, but the following factors will all play a role in the long-term success of the procedure.

The experience and qualifications of the people involved in the initial assessment as well as in theatre plays an important role. The patient needs a prompt, accurate diagnosis and adequate stabilisation prior to surgery.

An experienced surgical team will be able to diagnose and rectify the problem faster with better handling of the tissues, less contamination of the abdomen and less risk to the patient – thereby reducing post- operative complications.

The caecum – the surgeon is removing gas before closing the patient

Modern surgical suture materials and techniques causes less tissue reactions and better wound healing.

An experienced anaesthetist is critical to manage and monitor the colic patient, and horses in severe shock are especially challenging. Modern anaesthetic techniques and monitoring equipment significantly improve anaesthetic quality and survival. Positive pressure ventilation needs to be available as well as equipment to monitor arterial blood pressure, heart rate and rhythm (ECG), blood oxygen levels, expired carbon dioxide, levels of anaesthetic agents and body temperature.

Patient under general anaesthetic – note: the endotracheal tube, arterial blood pressure, ECG, Pulse oximeter, CO2 monitor – used to monitor the client.

Anaesthetic morbidity (complications that develop which are directly related to anaesthesia) and mortality (death during anaesthesia) rates are around 1% of all anaesthetic patients. The percentage of horses that will die from colic are far, far more than those horses that will die under anaesthesia or suffer complications that may necessitate euthanasia.

The anatomical location of the lesion may play a role in the outcome. Small intestinal lesions that require surgery may carry a poorer prognosis and a higher risk for post-operative complications than large intestinal lesions. However, this also depends on the type and the duration of the lesion. Broadly speaking, horses may have strangulating or non-strangulating lesions.

With strangulating lesions, the blood supply to the intestine has been severely compromised, and it is of utmost importance to correct these lesions before irreversible intestinal damage occurs.

A piece of strangulated small intestine. This piece has been irreversibly damaged and needs to be removed. Note: The dark red colour and distended blood vessels.

A strangulating lesion involving the caecum. In this patient, the caecum was resected and removed.

Once irreversibly damaged, these parts of the intestine need to be resected and removed and the remaining parts needs to be functionally joined. These surgical procedures are more complicated, and carry a bigger risk of contamination and subsequent complications. These procedures are also ttime-consuming thereby increasing risk for anaesthetic complications. Longer, more complicated surgeries are also more expensive and these horses tend to need more intensive post-operative care.

Examples of strangulation lesions include but are not limited to:

  • Colonic torsions (the large colon twisted around itself)
  • Epiploic foramen entrapment where (part of the small intestine gets trapped)
  • Pedunculated lipomas (fatty accumulation in the omentum that wraps itself around the small Intestine)
  • Small intestinal volvulus (intestine twists around itself)

Not all of these lesions are surgically accessible and cannot always be corrected. Occasionally, the lesion can be bypassed but some cases may need to be euthanased.

Non- strangulating lesions happen when parts of the intestine (small or large bowel) are displaced from the normal anatomical position but the blood supply to the intestine is not severely compromised. As the risk for irreparable intestinal damage is smaller, the prognosis may be better. However, some of these cases may have severe gas distention of any part of the intestine and they may rupture before surgical intervention. This will almost certainly necessitate euthanasia.

Gas distended small intestine – Note: the normal colour of the intestine

Examples of non- strangulating lesions – include:

  • Nephrosplenic entrapment (large colon displaces and becomes wedged between the kidney, spleen and body wall).
  • Right dorsal displacements
  • Pelvic flexure retro-flexions
  • Partial torsions
  • Anterior enteritis (inflammation of the small intestine) and grain overload
  • Ileal impaction or ileal hypertrophy

Ileal hypertrophy on a post mortem examination. Note the severely thickened intestinal wall

Colic surgery is a major procedure and some horses may suffer from peri/post-operative complications.

Postoperative ileus is the most common complication after small intestinal surgery.

This is when the small intestine doesn’t contract in a propulsive manner and leads to distention of the small intestine. The stomach then subsequently fills with fluid. There are numerous factors that contribute to the development of ileus. Nature of the lesion, duration of colic, amount of handling of intestine, endotoxemia. Due to the anatomy of the stomach horses are unable to vomit and the stomach can rupture if the situation is not managed intensively. A ruptured stomach will necessitate humane euthanasia.

Endotoxemia is another possible complication. This happens after tissue damage in the intestinal tract that leads to increased permeability of the intestinal wall. Bacterial toxins then cross the intestinal wall and enter the bloodstream, potentially leading to serious complications such as shock, laminitis, organ failure and death.

Mucous membranes of a patient with endotaxemia. – This horse was euthanased.

Incisional infections and subsequent hernias may develop. There are numerous factors that may contribute to the development of infections and include, but is not limited to, length of surgery, contamination during surgery, experience of surgeon, suture material used and cardiovascular status of horse during surgery.

Horses may develop adhesions after surgery where some parts of the intestines adhears to each other or the abdominal wall. This may lead to further episodes of colic. The highest risk for recurrence of colic post-operatively is in the first 100 days.

Owners should be aware that older horses (in their 20s) tolerate colic surgery well.

Horses can return to prior levels of performance after colic surgery and can successfully compete at the highest levels.

Horses with incisional hernias can also successfully return to demanding sporting actives.

Colic surgery is extremely expensive, especially when it happens on an afterhours basis. Few people can afford the costs involved. There are a number of insurance companies that offers critical care policies. These will cover up to R80 000 of the costs involved. PLEASE NOTE that if you have insurance – you are OBLIGATED to contact a veterinarian as soon as your horse shows any signs of illness. You may not treat the horse yourself, please ensure that you are familiar with the rules outlined in your insurance policy.

Closure of the mid-line at the end of surgery


  1. The most important factor in the success of colic surgery lies in the early recognition and prompt referral to a surgical facility!
  1. Ultrasonography plays a critical role in the early diagnosis of lesions that require surgery.
  1. An experienced colic surgery team plays an important role in the diagnosis, surgical repair and post-operative treatment to facilitate a successful outcome.
  1. Colic surgery is expensive – get the necessary cover.