Experimental large colon resection at the cecocolic ligament in the horse.

The researchers performed an experiment where they removed approximately 95% of the large colon in ten healthy horses using surgical stapling equipment. Some horses experienced complications and died post-surgery, but five of them survived in the long term without any adverse effects. Weight loss and soft feces were noted in the horses following the surgery, but they returned to preoperative states within a year.

Experiment Design and Procedure

• The research team conducted an experimental colon resection, where around 95% of the large colon’s length was removed surgically in ten normal horses.
• A side-to-side anastomosis, the process of reconnecting two sections of the colon, between right ventral and right dorsal colon was performed using a surgical stapling equipment, specifically the TA 90 transection staple line.

Post-operative Outcomes and Challenges

• Four horses died shortly after surgery due to complications like colitis (1 horse) or the failure of the staple line (3 horses), while another horse, which had initially recovered well from the surgery, died four months later due to a scattered streptococcal infection.
• Five of the horses survived long term (18 months), and there was no clinical evidence to suggest any adverse effects because of the colon resection procedure.

Recovery and Long-term Effects

• The horses that survived experienced weight loss and had soft feces for about 3 to 12 weeks after the procedure; however, they returned to their preoperative values within a year.
• During a second surgery or necropsy performed later, the researchers noted fibrous omental adhesions (fibrous bands that form between tissues and organs, often as a result of injury) over the staple line in some of the horses. One horse had an incisional hernia.
• The researchers found that the stapled stomata (openings created in the colon during surgery) were about 60% the size of the original ones created during the procedure.
• Troubles with the staple line, such as improper configuration or tissue crushing between the staples, led to its failure in three cases.
• With increased experience and learning from the initial attempts, the researchers were able to control this complication more effectively in the later stages of the study.