By: Dr. J.C. Thieke
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.
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.
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.