How to surgically treat intestinal necrosis caused by umbilical hernia in pigs

If a pig's umbilical hernia is treated in time, it is generally very easy to cure and intestinal necrosis will not occur; if treatment is delayed, the intestinal tract that has fallen into the hernial sac will undergo necrosis. In most cases where necrosis occurs, the hernial ring is relatively small, and the fallen intestinal tract undergoes necrosis due to insufficient blood supply caused by strangulation by the hernial ring; in a few cases, although the hernial ring is large, the fallen intestinal tract undergoes necrosis due to prolonged stimulation by the contents (even putrid contents). Based on the circumstances, we have used surgery to treat many cases of intestinal necrosis caused by umbilical hernia in pigs, with good results. The following is presented for reference.

1 Clinical symptoms

A sac-like swelling can be seen at the umbilicus, the size of a fist or even larger. Generally, at the beginning of the disease the pig eats normally, and because it eats normally, farmers usually do not treat it at this time. After 2 to 3 months (in prolonged cases up to half a year), the sac-like swelling enlarges, and the affected pig stops eating or eats only a small amount of food; at this time the body temperature is generally slightly higher than normal, and squeezing the sac-like swelling with the hand causes a painful sensation. Farmers generally seek treatment only at this time, because farmers usually judge whether a pig is sick based on how much it eats; a pig that eats little or does not eat is considered sick.

2 Surgical treatment

2.1 Preoperative management: fast the pig for one day before surgery, and restrain it in dorsal recumbency; thoroughly clip the hair of the hernial sac and its surroundings clean with hair-clipping shears, wash with 0.1% benzalkonium bromide solution, then disinfect twice with 5% iodine tincture, and wipe off the iodine with 75% alcohol cotton balls; use 0.5% procaine hydrochloride injection 10 to 30 ml (generally 10 ml for piglets and 30 ml for medium and large pigs) to perform layered infiltration anesthesia at the bottom and base of the hernial sac respectively, and begin surgery 5 minutes later.

2.2 Surgical procedure

2.2.1 (1) Use a scalpel to make a longitudinal incision through the skin from the front and rear base of the hernial sac, and bluntly separate the skin from the connective tissue down to the base of the hernial sac; (2) incise the subcutaneous connective tissue sac (necrotic intestinal tract may be visible), and separate the peritoneum; if the hernial ring is small, slightly enlarge it with tissue scissors to facilitate the entry and exit of the intestinal tract and mesentery into and out of the abdominal cavity; (3) pull out the intestinal tract along both ends of the necrotic intestinal tract within the hernial sac until healthy intestinal tract is seen, then protect the intestinal tract with a large gauze soaked in penicillin saline and isolate the surgical site; according to the extent of the necrotic portion of the intestinal tract, determine the range of resection of the intestinal tract and mesentery, and determine the incision line; the blood vessels on the mesenteric incision line are doubly ligated on the root side, then two intestinal forceps are used to clamp the intestinal tract at 3 to 5 cm from the cut edge at both ends respectively, serving to fix the intestinal tract and block the outflow of intestinal contents; (4) according to the determined incision line, resect and remove the necrotic intestinal tract and mesentery, aspirate the contents within the intestinal tract at the severed ends with sterile gauze, and after wiping clean, flush the intestinal mucosa several times with penicillin saline.

2.2.2 Conventional end-to-end anastomosis. In cases encountered clinically, the calibers of the two severed ends of the intestinal tract are mostly equal; in this situation, conventional end-to-end anastomosis is used to anastomose the intestinal tract. That is, bring the two intestinal segments close together so that the severed ends of the two intestinal segments are adjacent. First, on the mesenteric side and the antimesenteric side of the two intestinal ends, place one suture each through the full thickness of the intestinal tract with No. 4 silk thread at about 0.5 cm from the severed end of the intestine, to fix the two severed ends and facilitate suturing. Then use a straight suture needle to pass from the intestinal lumen out through the intestinal wall on the antimesenteric side of one intestinal segment, then penetrate from the outside of the intestinal wall into the intestinal lumen of the other intestinal segment, and tie a knot so that the severed edges of the two intestinal segments are brought close together; continue using a continuous full-thickness suture method to suture the posterior wall of the anastomotic opening of the two intestinal segments until near the mesentery, then pass the suture needle from the inside of one intestinal wall out through the wall, and then pass the suture needle from the outside of the other intestinal wall into the wall, and pull the suture tight so that the intestinal wall near the mesentery is inverted; next, before anastomosing the two intestinal segments, use a continuous horizontal mattress inversion suture until the anterior wall is completely sutured. Tie the final thread end to the initially retained thread end. Then remove the intestinal forceps, replace the penicillin saline gauze protecting the intestinal tract, and after disinfecting the hands and instruments, use an interrupted vertical mattress inversion suture method through the seromuscular layer to perform the outer layer suture of the intestinal anastomosis; after suturing is completed, flush the intestinal tract again with penicillin saline.

2.2.3 Simple end-to-end anastomosis. Insert a stent (the stent is generally a peeled cucumber) into the intestinal lumen of the proximal intestinal segment to stretch the intestinal wall and facilitate suturing; directly sleeve the distal intestinal segment over the proximal intestinal segment, so that the mucosa of the distal intestinal segment faces the serosal layer of the proximal intestinal segment, then everting the intestinal opening of the distal intestinal segment so that serosa overlaps serosa; then use No. 4 silk thread to place several vertical buttonhole sutures along the fold line of the everted intestinal segment and the overlapping portion of the proximal intestinal segment, and tighten and tie them between the two intestinal walls; after flushing the intestinal segment with penicillin saline, evert the intestinal opening of the distal intestinal segment again so that its mucosa faces the serosa of the proximal intestinal segment, then place several interrupted vertical mattress inversion sutures around its severed end until the entire severed intestinal wall is sutured; remove the intestinal forceps, crush the stent within the intestinal lumen, push it toward the distal end, and flush the intestinal tract again with penicillin saline.

2.2.4 Return the intestinal tract to the abdominal cavity, sprinkle an appropriate amount of penicillin powder and streptomycin powder into the abdominal cavity, trim off excess peritoneum, and perform a tight continuous suture of the peritoneal opening; use surgical scissors to trim off excess subcutaneous connective tissue, and lightly incise the hernial ring to create a fresh wound surface, insert the needle circularly along the hernial ring, with the needle entry point about 1 cm beside the hernial ring; when inserting the needle, extend the left index finger between the peritoneum and the muscle layer, so that the needle penetrates only the muscle and not the peritoneum; the needle spacing need not be too dense; after one full circle of needle insertion, leave tying threads at the needle entry end and the needle exit end, and close the hernial ring with a continuous suture method; moderately tighten the tying threads left by the circular suture and tie a knot, sprinkle an appropriate amount of penicillin powder and streptomycin powder onto the wound, excise excess skin, and suture the skin incision with an interrupted suture method, apply 5% iodine tincture, finally apply a tie-over bandage, and then release the affected pig.

2.3 Postoperative care: place the affected pig in a clean pen bedded with fresh dry straw, and give intramuscular injections of penicillin twice daily for 7 consecutive days. Within 7 days after surgery, give the affected pig some cold boiled water or sugar-salt water, and after 7 days gradually feed some easily digestible feed.

3 Summary and discussion

3.1 In clinical practice, 278 cases of intestinal necrosis caused by delayed treatment of umbilical hernia in pigs were admitted. In 120 cases in which the intestinal tract was sutured with conventional end-to-end anastomosis, the pigs showed varying degrees of digestive hypofunction after surgery, reduced feed intake, emaciation, constipation, and varying degrees of hindrance to growth and fattening. In 158 cases in which the intestinal tract was sutured with simple end-to-end anastomosis, none of the pigs showed any digestive disturbance after surgery, feed intake and defecation were normal, and growth and fattening were good.

3.2 Although the conventional traditional end-to-end anastomosis meets the requirements of anatomy and physiology, it is prone to intestinal stenosis after surgery, causing digestive disturbance, affecting the body's digestion and absorption, and hindering the growth and fattening of pigs. The simple end-to-end anastomosis overcomes the problem of postoperative intestinal stenosis, and is simple to perform and saves time. From the perspective of anatomy and physiology, the effect is good.

3.3 The simple end-to-end anastomosis directly sleeves the distal intestinal segment over the wall of the proximal intestinal segment, and at the same time the first suture line uses vertical buttonhole sutures, so that the overlapping portion of the two intestinal segments is tightly connected and leakage is unlikely to occur, and all sutures are embedded within the intestinal wall; the second suture line is also an interrupted vertical mattress inversion suture, which makes the intestinal tract at the anastomosis smooth and flat both inside and outside, ensuring patency of the intestinal lumen, and intestinal adhesion will not occur.

3.4 In the surgical treatment of intestinal necrosis caused by umbilical hernia in pigs, simple end-to-end anastomosis has better efficacy than conventional traditional end-to-end anastomosis, and the surgery is simple and time-saving, so it can be widely promoted and used in clinical practice.