No word strikes fear into the heart of a horse owner more than ‘colic’, and most will have experience of it in some context. Unfortunately, colic remains one of the biggest causes of death in horses worldwide. And it is the number one reason horse owners call a vet outside of normal hours in the UK. Only around 10% of colic cases in the UK require surgical treatment. But it can be a risky procedure which is usually only carried out in a designated hospital facility. This article aims to summarise why only a small proportion of colic cases require surgery, what the surgery may involve and why it requires referral to a designated equine hospital or surgical facility. 

Table of contents

What is colic?

Colic is an umbrella term used to describe abdominal pain, which can be caused by a variety of pathologies of varying severity, ranging from spasmodic colic caused by abnormal contraction of the gut, to impactions and torsions of the intestine. 

Symptoms of colic are very variable but can include pawing at the ground, flank watching, rolling, restlessness, sweating and kicking at the belly. 

The treatment options for colic depend on the suspected cause and severity of symptoms. Some causes of colic can be treated with medical management alone, whereas others require surgery. Seeking veterinary help as soon as colic symptoms are noticed ensures the horse has access to the treatment it needs, increasing the likelihood of a positive outcome. 

Why do some cases of colic need surgery?

Broadly speaking, colic can be classified as either medical or surgical; with around 10% of colic cases seen in the UK needing surgical treatment. A colic is classified as surgical when blood supply to part of the intestine is cut off due to a twist (torsion) or a displacement, the case has failed to respond to medical management e.g. in an impaction colic or when a horse is so painful that medical management alone is not enough. The decision to take a horse to surgery will be based on the severity of your horse’s symptoms, their physical parameters (e.g. heart rate), results of diagnostic tests carried out by the attending or hospital vet, and the horse’s response to initial medical treatments such as pain relief and fluid administration. 

What does colic surgery involve?

Colic surgery involves a general anaesthetic and investigation of the abdominal cavity by a veterinary surgeon. Depending on the severity and cause of the colic, the intestine may need to be emptied, repositioned, or a section may even need to be removed. 

Due to their size, extremely specialised equipment is needed to carry out these procedures. As well as specially trained members of staff, including veterinary anaesthetists, veterinary surgeons, surgical nurses and assistants.

Anaesthesia…

Equine anaesthesia generally carries a higher risk than small animal and human anaesthesia. This is due to horses’ size, weight and prey animal instincts. Preliminary results from the Fourth Multicentre Confidential Enquiry into Perioperative Equine Fatalities (CEPEF4) Study found that “overall mortality rate for general anaesthesia within the seven-day outcome period was 1.0%”; which is significantly higher than the 0.17% mortality rates seen in canine general anaesthesia (Deutsch and Taylor, 2021). Horses’ size and weight can compromise their lung function, potentially leading to low blood oxygen levels and muscle damage. Alongside this, the recovery period carries significant risks of trauma.

Emergency colic surgery generally carries a higher risk of mortality and complications than elective procedures (i.e. non-emergency) because affected animals are often already systemically unstable and very sick.

These risks are minimised in a hospital setting through utilisation of specialised equipment such as a ventilator, which breathes for the horse during surgery, oxygen supplementation, sophisticated anaesthetic monitoring equipment and dedicated recovery rooms with padded walls and methods of assisting the horse in recovery. 

Complications post-operatively can also occur, such as infection, recurrent colic episodes or wound break down.

Despite these potential complications, it is important to remember that the majority of surgical colic cases don’t experience complications; with 62-77% surviving to discharge from hospital following surgery (Burford, Doulas, England and Freeman, The School of Veterinary Medicine and Science at the University of Nottingham).

Why does my horse need to be referred for surgery?

If a horse requires surgery, the attending vet will usually recommend referral to a hospital facility where they are equipped to deal with emergency colic surgeries.

There are several reasons why the vet will recommend referral

Attending vets are generally ambulatory, meaning they only have access to the equipment they carry in their cars, and referral to a hospital facility is often the fastest way to gain access to further diagnostic equipment, as well as surgical facilities if needed. Additionally, veterinary staff at designated hospitals have often undergone specialist training in their field. And equine surgeons generally hold additional qualifications in equine specific surgical procedures. 

It is important to remember that referral to a hospital doesn’t always mean the horse is going to have surgery. But it does mean hospital vets can perform more in depth diagnostic tests; which the attending vet may not have access to. And they are often better equipped to provide more intense medical management which may be impractical to carry out in the field. If surgery is required, prompt action may lead to a more favourable outcome, with less risk of peri and post-operative complications. Additionally, transporting a horse to hospital early on in the process reduces the additional stress of transporting a critically sick animal. 

As discussed, colic surgery is an extremely challenging and often risky procedure 

If the horse does need surgery, it should never be attempted in a field setting for several reasons. Firstly, opening the abdominal cavity in horses presents a risk of life threatening infection, which is minimised in a designated equine theatre through stringent management and control procedures. A field or stable setting are, by their nature, heavily contaminated environments and performing major surgery in such settings increases this risk dramatically. 

Secondly, performing a general anaesthetic that is likely to take several hours without access to oxygen supplementation increases the risk of complications associated with a lack of oxygen supply, such as muscle and brain damage. Ambulatory vets usually carry the drugs needed for inducing anaesthesia, and will often perform short, routine procedures such as castrations in the field, but longer, complex procedures are impractical and unsafe in such settings. As well as a lack of oxygen supplementation, the inability to monitor the horses parameters accurately during anaesthesia poses additional risks to the horse, vet and owner if the plane of anaesthesia becomes either too deep or too light. 

Finally, a horses recovery from anaesthetic can be associated with some of the highest rates of complications and mortality, including catastrophic fractures, wound breakdown, respiratory arrest and trauma. In a hospital setting, recovery is carried out in a controlled environment, with some facilities using rope or even water assisted recoveries to minimise the risk of these complications occurring. Recovery outside of these controls increases the risk of complications dramatically, as well as putting the safety of personnel at risk.

It is also important to remember that surgery is often only the first part in a very long road to recovery

In the majority of cases, weeks to months of post operative critical care is needed. Strict box rest, intravenous fluid therapy, nutritional support, wound dressing and antibiotic therapy are just some of the things provided when a horse stays in a hospital. Providing this level of care outside of the hospital environment is often impractical and riskier for the patient. 

Summary

Colic is an umbrella term used to describe abdominal pain, which can be caused by a variety of pathologies of varying severity. The vast majority of colic cases can be medically managed, and those that do require surgery usually recover without complications. Colic surgery is however a major procedure, and can carry with it a significant risk of complications. These complications include life threatening infections, insufficient blood oxygen levels during surgery, recovery related injuries such as catastrophic fractures and post-operative complications such as recurrent colic and wound breakdown. 

Carrying out this procedure in a highly controlled hospital environment minimises these risks as much as possible, which is why colic surgery should never be performed in the field. Referral to an equine hospital does not immediately mean a horse will go for surgery, but it does mean more in depth diagnostic tests are available, and the horse is in the right place to have surgery if it is required. The faster a horse goes to surgery if it is necessary, generally the more favourable the outcome. 

Recognising colic signs and acting on them promptly is key in ensuring the horse receives the treatment it needs. Contact your vet as a matter of urgency if you think your horse is showing signs of colic. 

References and further reading