What is involved in colic surgery?

By: Dr. J.C. Thieke

Colic Surgery

Doctors examining the intestines.

Colic is the catch-all term used to describe abdominal pain. In many cases, it is a problem with the horse’s intestinal tract. While most colic cases can be treated and resolved with medical therapy such as pain management, IV fluids and stomach tubes; sometimes surgical intervention is required.

The cases that require surgery are those with unrelenting pain that cannot be managed medically and/or have pre-surgical diagnostics such as a rectal exam, ultrasound exam, or belly tap that suggest a surgical problem. In surgical cases, it is always considered an abdominal exploratory. While the pre-surgical diagnostics and blood work can help shed some light on the cause of the colic, they cannot answer all the questions prior to surgery.

Before colic surgery, the patient will have an IV catheter placed in the jugular neck vein. This provides venous access to easily deliver medications and IV fluids during surgery and post-op. A naso-gastric (stomach) tube will be placed and taped in place so any fluid (reflux) that comes up out of the stomach can be controlled and kept out of the horse’s lungs. His mouth will also be rinsed out and antibiotics and pain medication will be given. The hair on the abdomen will be clipped either prior to anesthesia induction, or after the horse has been positioned on the surgery table.

Anesthesia is induced with injectable medications and the horse, as he becomes unconscious, is guided down to the floor. At this point an endotracheal tube will be placed into his trachea so that he can be connected to the gas anesthesia machine. Once the tube is placed, the horse is lifted with a hoist by the legs and positioned on the surgery table. The anesthesia is maintained using an anesthetic gas just like in humans. An EKG monitors heart rate and rhythm, and an arterial catheter directly measures blood pressure.

Once the final clip of his abdomen is completed, the area is scrubbed with a surgical scrub that typically takes 7-10 minutes. The abdomen is sterilely draped, making the surgical preparation complete.

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Small intestines showing healthy pink tissue on the left and red dying small intestines on the right.

A 1 4 to 16 inch length-wise incision is made along the ventral abdomen (the bottom of the belly in a standing horse). The exploratory begins by first palpating the abdomen for the inciting cause. In some cases the intestine is so gas distended that a suction unit and needle are used to pull the gas out of the intestine. This allows the two surgeons ample room to sort through the different parts of the intestine. Ideally the cecum, which is similar to the appendix in humans, is the first part of the intestine to be exposed through the incision. If it is not easily exteriorized, then a large intestinal torsion may be the cause of the colic. The large colon is lifted up and out of the abdomen with care to not tear the colon wall as it is manipulated. In the case of a torsion, the twist is reduced by rotating the colon in the correct direction until the cecum comes free, indicating it is now in the correct position. In most large colon surgeries, the contents of the colon need to be removed to either relieve an impaction or remove accumulated toxins from the twisted colon as a result of decreased blood flow due to the torsion. To remove the intestinal contents (an enterotomy) the colon is positioned on a tray and an incision is made to allow the contents to be flushed out; meanwhile, the inside lining of the affected bowel is assessed to provide important information regarding the horse’s prognosis. The incision in the bowel wall is closed in two layers, thoroughly rinsed, and placed back into the abdomen in the correct position.

Colic

Round worms in the small intestines of a weanling causing an impaction.

A small intestinal problem is typically evident immediately once the abdomen is opened.  Stretched out and gas distended small intestine indicates a small intestinal obstruction. This can be caused by the small intestine getting stuck in an abnormal location, twisting on itself, or having a tumor wrap around a section of it. If the blood flow to a section of small intestine is compromised, that section may die and need removal. This procedure (an anastamosis) requires tying off the blood supply to the affected section, cutting the section out, and reconnecting healthy intestine to healthy intestine. Once complete the repaired intestine is placed back into the abdomen.  A thorough final exam is performed on the remainder of the abdomen. This includes: the liver, small colon, spleen, kidneys, and the ovaries and uterus in mares. A special solution (carboxymethylcellulose or belly jelly) is placed in the abdomen to help minimize the risk of adhesions between the abdominal contents.

Finally, the large initial abdominal incision is closed in 3 layers: the body wall and layer below the skin (subcutaneous) with suture, and the skin with staples. A bandage is sutured onto the skin and the horse is removed from gas anesthesia to recover. We ask a lot from them post anesthesia. They will stand on their own, which usually takes around 30 minutes. Once the horse is stable enough to walk and back in the stall, they will be hooked back up to IV fluids and medication will be given to stimulate intestinal motility. The normal recovery from colic surgery will include 5-7 days in the hospital on fluids, antibiotics, and pain management. In many cases, acupuncture is used to stimulate intestinal function and for additional pain management. If all proceeds as planned, food will be re-introduced over the next several days. Once the horse is off all medications and on full feed, they can be discharged.

Recovery at home is 6 weeks of stall rest with the skin staples being removed 2 weeks post-op. Stall rest is followed by six weeks in a small pen and then a gradual return to work and pasture turnout. Success rate varies on the type of colic surgery performed but on average about 75% of horses that have colic surgery survive and go back to their normal activity.

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Impaction Colics

By: Katie Jones, CVT

Colic. This word alone makes most horse owners cringe with just the thought of it. It is a moment horse owners hope to never face with their four-legged friends. The term “colic” is actually a very vague term that refers to any abdominal pain a horse is experiencing. Colic is predominantly used to describe pain caused by the gastrointestinal tract, but other abnormalities may cause a horse to exhibit colic like symptoms. With the weather changes winter can bring, horses can be at an increased risk for impaction colic.

Anatomy

ImpactionThe gastrointestinal tract of the horse is about 100 feet long with most of it consisting of the intestines. Food initially enters the mouth and travels down the esophagus and into the stomach. Horses do not have reverse peristalsis; meaning, food can only travel in one direction and they can not vomit.   In contrast to other grazing animals, horses are a monogastric species only having one compartment to their stomach which is divided into squamous and non-squamous portions. Once the food leaves the stomach, it enters into the small intestines (50-70 feet long) through the pylorus where most of the digestion and nutrients are absorbed into the bloodstream. Any remaining liquids and roughage is then moved into the large intestine.

The first part of the large intestine is the cecum (4 feet long), which is a blind sac. This area of the intestine has bacteria that digest plant fiber through fermentation, making the horse a “hind-gut fermenter.” The reason horses need to have their diets changed slowly is to allow the bacteria in this region of the gut to modify and adapt to the different chemical structures of the new feedstuff. After the cecum, feed enters the colon. Although the colon is a much shorter structure then the small intestine at around 20 feet, this area of the GI tract undergoes abrupt changes in direction and decreases in the lumen diameter; all of which causes it to be a common place for impactions.

An impaction is a formed blockage of feed stuff or other materials in the intestines. Although an impaction can occur anywhere within the intestines, there are several sites were they are seen more commonly.

Pelvic Flexure Impaction

The pelvic flexure is a portion of the large colon that normally sits in the left side of the impaction1abdomen near the left flank. This area is a common place for impactions to develop due the lumen diameter decreasing rapidly and the abrupt direction change. This form of impaction will cause a horse’s fecal output to decrease, if not stop. Pelvic flexure impactions are diagnosed via rectal palpation. Treatment will consist of a veterinarian placing a nasogastric tube down the horse’s esophagus and administering mineral oil mixed with water. The goal is to provide fluid to soften the impacted feed material. If the horse does not respond to the oral fluid treatment, the horse may need to be given fluids intravenously. Pelvic flexure impactions that do not respond to medical treatments or their pain level gets too high will eventually require surgery.

Cecal Impactions

Due to the cecum being a blind-sac, feed material enters and exits through the same end; predisposing impaction problems in this area. Cecal impactions are diagnosed by feeling a mass on the right side of the abdomen during a rectal palpation. The early treatment plan is similar to a pelvic flexure impaction (oral and IV fluids), but distention of the cecum can lead to rupture quickly often making surgical intervention a necessity to prevent rupture.

Small Colon Impaction

Small colon impactions are most commonly caused by fecal material (fecolith) after diarrhea episodes or meconium in foals. Miniature horses are predisposed to small colon impactions. Diagnosis can occasionally be done by rectal palpation; however, in cases where the area can not physically be reached, a diagnosis is made based on clinical signs. When a small colon impaction is secondary to diarrhea, the horse may exhibit a fever, a low white blood cell count, or numerous other clinic signs associated with endotoxemia (the presence of endotoxins in the blood). When the horse is systemically compromised, treatment starts similar to other impactions, but will also be treated with antibiotics, anti-inflammitories, and/or anti-endotoxic medications. Horses with small colon impactions may respond to medical treatment, but often require surgery if they continue to display colic-like symptoms after treatment has been started.

Colic prevention quite honestly comes down to management practices. Regardless the time of the year, it is important to provide high quality roughage and ample clean water. During the winter months, providing water buckets free of ice and at a slightly warmer temperature will encourage horses to drink even in extremely cold weather. Intestinal contents have a high water content which produces a soupy consistency as it passes through the GI tract. Horses should consume around 10 gallons of water per day, even in very cold weather, to maintain this high moisture content. Annual dental examinations will not only prevent the development of dental issues, but they will also allow the horse to properly chew their forage; therefore decreasing the chance of an impaction colic. Having a close relationship with a veterinarian will help in formulating a feed and management program to prevent impactions.

SmartPak Colic Care : https://www.smartpakequine.com/ColiCare

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