Surgical intervention is, unfortunately, necessary for many horses that experience colic, with 4 – 10% of colic cases requiring surgery. 
The term colic refers to abdominal pain of any cause. Colic may be caused by something as simple and transient as a trapped air bubble or something more alarming, such as complete impaction or a twist in the intestines.
In severe cases, colic surgery is used as a diagnostic and therapeutic procedure. The extent of some instances of colic cannot be determined until the abdomen is opened.
Surgery of any kind introduces risks for your horse and your veterinarian will only suggest this procedure if other treatment strategies are unlikely to be successful.
If colic surgery is required, the faster your horse undergoes the procedure the more likely they are to survive. The recovery rate for horses undergoing colic surgery is 73.5%. 
If your veterinarian tells you that colic surgery is necessary for your horse, make sure you understand why the procedure is being performed, the type of surgery, risks and benefits, and recovery expectations.
Surgical vs. Medical Colic
Colic can be separated into two categories: medical or surgical.
Medical colic describes all cases that can be treated with relatively non-invasive techniques, such as nasogastric tubing and pharmaceutical medications. Surgical colic requires opening the abdomen to manipulate the intestine.
It is important to note that colic that first appears to be medical can develop into surgical colic and colic that routinely requires surgery can sometimes be treated medically.
Medical colic includes:
- Ulcerative colic
- Gas colic (before displacement)
- Some sand colic
- Mild impaction colic
Surgical colic includes:
- Severe impaction
- Intussusception (telescoping of the intestine)
- Strangulating lipoma (a fatty tumour reducing blood flow to the intestine)
- Volvulus (twisting of the intestine)
- Entrapment in the abdominal structures
- Enterolith (a large stone in the stomach)
- Scar tissue lesions
- Intestinal herniation 
In a research review of horses treated at a South African equine referral hospital, the most common causes of surgical colic included displacement (29%), impaction (22%) and small intestinal strangulating lesions (18%). 
Treatment for Colic
Most veterinarians will try to manage colic conservatively at the home farm first to minimize the risk of complications.
Your vet will insert a nasogastric tube to introduce medication directly into the stomach, manage the horse’s pain, monitor vitals, and support the horse with IV fluids.
Throughout the treatment, your vet will monitor for signs that conservative intervention is failing and the horse is getting worse. These signs include: 
- Uncontrolled pain, even with aggressive pain management
- Gas or fluid reflux appearing through the nasogastric tube, indicating a complete blockage
- Unstable vitals that are not improving with treatment
- Signs of circulatory issues including rapid breathing, shaking, weak pulse, pale membranes, and cold extremities
- General lack of response to treatment
Determining the Cause of Colic
Your veterinarian will also have a thorough discussion with you about your horse’s history to determine what the most likely cause of the colic episode is.
For example, if your horse has recently been turned out on grass for the first time and the physical exam does not point to obstruction or torsion, your vet may diagnose your horse with grass colic, which can be managed at home.
If your horse recently had abdominal surgery, colic may be caused by scar tissue adhesions that are obstructing blood flow. This type of colic requires surgical intervention. 
By taking into account your horse’s history, the results of the physical exam, and your horse’s response to treatment, your vet can determine if conservative management at home is likely to ease the colic or if surgical intervention is warranted.
Should colic surgery be necessary, your veterinarian will also determine which procedure to perform: laparoscopic surgery or exploratory celiotomy.
Laparoscopic Colic Surgery
Laparoscopic surgery is a less invasive surgical approach. This surgery is performed under standing sedation, meaning your horse is not intubated or put under general anesthesia.
The procedure is performed by inserting a camera and surgical instruments through a small incision on the side of the abdominal wall. Unlike exploratory celiotomy, the abdomen does not need to be completely opened.
Because of the small incision site, laparoscopic colic surgery has limited use. It is commonly used in cases involving minor adhesional colic and some forms of entrapment colic.
In cases of minor adhesional colic, scar tissue has grown around a location that is restricting blood flow to the intestines.
Adhesions are bands of scar tissue that bind two or more unconnected tissues together. Scar tissue is formed during the healing process after trauma or infection (i.e. after foaling, abdominal surgery, or peritonitis).
The cells responsible for generating scar tissue cannot differentiate between multiple tissue types and can produce adhesions that interfere with physiological function. 
Adhesions can become so extensive that they restrict blood flow to or block the passage of digestive contents through the intestines.
If the adhesions are small and close to the surface of the abdomen, a laparoscopic procedure can separate the bands of tissue and alleviate the colic. 
Laparoscopic surgery can also be used in some cases of entrapment colic, such as nephrosplenic entrapment in which the left dorsal colon moves from its original position and settles over the nephrosplenic ligament.
This ligament connects the left kidney to the spleen. When the colon settles over this ligament, colon contents can get stuck causing distension and pain.  Veterinarians do not yet understand why this occurs in some horses and not in others, but this form of colic does require intervention.
Some cases of nephrosplenic entrapment can be treated by jogging the horse to jostle the colon back into place and administering phenylephrine – a drug that reduces the size of the spleen.
It is also possible to anesthetize the horse and roll them repeatedly to reposition the colon. However, most cases of nephrosplenic entrapment require laparoscopic surgery to address the blockage. 
Nephrosplenic entrapment is diagnosed via rectal palpation, ultrasound, or surgery.
If your horse has been admitted to the surgical hospital for laparoscopic surgery, they will be transferred to the surgical suite and prepped for the procedure.
In the surgical suite, the surgical staff will sedate your horse and place them in a cage-like device called stocks. The sedation and stocks ensure your horse is comfortable and stationary throughout the procedure.
An IV catheter is placed in order to administer fluids, antibiotics, anti-inflammatory drugs, and sedation. The staff will then clip the surgical area very close to the skin and scrub the area thoroughly to remove debris and bacteria. Drapes will be placed around the surgical area.
The surgical staff will then inject a local anesthetic into the area where the incisions will be made – typically on the left flank.
This procedure is conducted by two veterinary surgeons: one surgeon operates the laparoscope and the other operates the surgical instruments.
The surgeons will make multiple small incisions into the surgical area and push a camera probe (laparoscope) into the abdominal cavity, facilitating visualization of the contents.
The surgeons use a cannula to slightly inflate the abdomen with carbon dioxide, creating space for the surgeons to manipulate the intestines. The surgeons will then identify the procedure necessary to address the cause of the colic and insert any required tools. They will complete the necessary procedure, remove the tools and laparoscope, and staple the incisions closed.
After surgery is completed, the surgical staff will slowly wake your horse from sedation and move them to a recovery stall. The IV catheter usually stays in place until your horse is ready to go home. 
If the surgery went smoothly and to plan, your horse may be discharged the next day with instructions to orally administer antibiotics and anti-inflammatory medication. Your surgeons will ask you to closely monitor your horse’s temperature and comfort level.
You will be instructed to keep your horse on a clean bed of straw and to reduce debris contamination. Your horse should be kept on stall rest for 12 days, or until the staples are removed.
Your surgeon will instruct you on how and when your horse can return to work. Most horses recover completely in 3-4 weeks. 
If surgery does not go to plan, discharge and recovery will vary depending on the individual needs of your horse. It is crucial to follow your surgeon’s instructions to support your horse during their recovery.
Limitations and Risks
Only certain types of colic cases can be treated with laparoscopic surgery. Even in cases of adhesional colic, if the adhesions are too deep in your horse’s abdomen the surgeons may not be able to reach the location laparoscopically.
If your horse’s colic is caused by anything other than adhesions or minor displacement, laparoscopic surgery will likely not be an option. 
Because laparoscopic colic surgery takes place under standing sedation, the risks associated with undergoing general anesthesia are eliminated. Horses can still injure themselves waking up from sedation, but the risk of injury is greatly reduced.
When a horse is under general anesthesia, they must be laid down, flipped onto their back and intubated. Horses are not meant to lie on their backs for extended periods of time. The weight of their abdominal contents pushing against their diaphragm can impact their ability to breathe.
Laparoscopic procedures do not require flipping the horse, avoiding negative impact on the lungs.
Finally, laparoscopic colic surgery does not require complete separation of the abdominal muscles.
The horse’s abdominal muscles are important because they support hundreds of pounds of abdominal contents. In exploratory celiotomy, abdominal muscles are separated to explore the abdominal cavity.
Although they are strongly sutured back together after the procedure, the pressure can split the sutures resulting in herniation. Extreme herniation after surgery can be deadly. 
When most horse owners think of colic surgery, they are likely to picture exploratory celiotomy. This is the more invasive surgical option for treating colic, which requires general anesthesia.
Horses undergoing exploratory celiotomy must be completely asleep and flipped onto their back in order to make a long incision into the abdomen.
Most surgical colic cases will require an exploratory celiotomy, including:
- Intussusception (telescoping of the intestine)
- Volvulus (twisting of the intestine)
- Major adhesions
- Enteroliths (stones in the stomach)
This procedure is indicated whenever the intestine needs to be partially removed from the abdomen in order to eliminate the source of colic. 
When your horse is admitted to a surgical hospital for colic surgery, an IV catheter will be placed to administer fluids and pain medication.
If your horse is relatively stable, your veterinary surgeon may decide to fast your horse for 24 hours to reduce the risk of post-surgical colic.  If your horse is unstable, the risk of abdominal rupture is higher than the risk of post-surgical colic and surgery will proceed without a fasting period.
Your horse will be transferred to a padded general anesthesia suite where they will be sedated to reduce anxiety and stabilize their vitals. General anesthesia will be administered through the IV catheter.
The surgical staff will gently help your horse to the ground, using the padded walls of the room to assist them.
When your horse is no longer showing reflexes such as pulling the tongue back and blinking, the staff will insert a large tube into their trachea to administer anesthetic gas and oxygen directly to your the lungs.
The surgical staff will place straps on your horse’s feet to lift and transport them to the surgical suite. Your horse will be placed on their back on the surgical bed and supported in position by blocks.
To reduce the risk of contamination, wraps will be placed on your horse’s hooves and their entire abdomen will be clipped close to the skin. The abdomen will be thoroughly scrubbed with antiseptic solution and surgical drapes will be placed around the area.
Monitoring equipment will be placed on your horse to ensure their vitals remain stable. Fluid and medication will be administered to your horse throughout the procedure.
The veterinary surgeon will make a large incision starting at your horse’s sternum and extending straight down towards your horse’s pelvis. The surgeon will cut through the fat, connective tissue, and muscle of the abdomen to expose the abdominal cavity.
The surgeon will then examine the intestines and stomach thoroughly for the cause of colic. If there is an impaction or enterolith, the surgeon will make an incision into the intestine or stomach to remove the material.
If there is an intussusception or volvulus, the veterinary surgeon will restore the intestine to its proper position. If there is any necrosis (tissue death) of the intestine, the surgeon will remove the dead intestine and reattach the healthy ends.
The surgeon will then close the incision in layers and wrap the abdomen in a tension bandage to support the muscles.
Your horse will then be transported to the recovery room where they will be closely monitored. Different hospitals use different waking protocols, but in all cases, the surgical staff will wake your horse slowly and carefully. Your horse will then be walked to a stall for recovery to continue. 
Because exploratory celiotomy is a highly invasive surgery, the recovery time is extended and more complicated compared to laparoscopic surgery. Your horse will likely be on stall rest for approximately 8 weeks with slow hand walking permitted.
Ventral abdominal incisions are slow to heal and care must be taken to avoid stress on the incision. Your surgeon will advise you on when to remove the tension bandage. 
Follow your surgeon’s feeding instructions carefully. Most veterinarians advise eliminating or reducing concentrates to reduce strain on the digestive tract. A nutritionist can help you formulate a diet to support recovery and prevent future colic episodes.
Your horse will be prescribed oral antibiotics and anti-inflammatories. Monitor your horse very closely for signs of infection such as:
- Increased temperature
- Reduced appetite
- Pus or swelling of the incision
Extended use of non-steroidal anti-inflammatory drugs also poses a risk of side effects. Ask your veterinarian about using COX-2 selective NSAIDs, which have a lower risk of adverse events.
Be aware of the risk of post-surgical colic and call your vet immediately if your horse seems off.
Limitations and Risks
Exploratory celiotomy comes with risks that should be considered before consenting to the surgery. Opening the abdominal cavity increases the risk of infection and post-surgical adhesions.
Separating the abdominal muscles also introduces a risk of post-surgical herniation in which the incision splits from the weight of the abdominal contents.
This can result in either an enclosed herniation (in which the skin holds the contents after the muscle has split) or – in rare cases – an evisceration (in which the contents fall through the muscle and skin).
While proper use of tension bandages significantly reduces the incidence of herniation, the risk is still present. 
Putting a horse under general anesthesia also carries its own risk. As stated earlier, lying your horse on its back for an extended period of time can put pressure on the lungs and make breathing difficult.
Your horse is intubated to force air into their lungs, partially reducing this risk. Additionally, colic surgery is performed as quickly as possible to minimize the time your horse spends on their back.
Waking up from general anesthesia while lying down is also disorienting for horses. They will often try to rise to their feet before they are stable and can severely injure themselves in the process.
Fortunately, the surgical staff are highly experienced in waking horses from surgery and will support your horse to avoid injury.
Although exploratory celiotomy carries risks, it is sometimes the only option. Veterinarians at surgical hospitals undergo rigorous training and have performed this procedure multiple times.
Your horse is monitored closely to ensure they remain stable and the staff will intervene if there are any indications of problems. Recovery rates after exploratory celiotomy are estimated to be around 73.5%. 
It can be intimidating if your horse has to undergo colic surgery, but know that the veterinarians caring for your horse are experts and will do their best to support your horse through the episode.
Going into the procedure as an educated horse owner can reduce your anxiety and promote a positive outcome.
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