Intestinal surgery (part 1) (Proceedings)
Complications associated with intestinal surgical procedures can be reduced by attentiveness to the principles of intestinal surgery and appropriate use of ancillary procedures such as serosal patching.
Surgical principles and technical details of intestinal surgery
The following principles should be followed when performing intestinal surgery: establish an early, accurate diagnosis, isolate the area to be incised, minimize tissue trauma, minimize contamination, preserve the blood supply, maintain an adequate lumen, achieve a secure closure, avoid tension across the suture line, protect the suture line, and accurately assess intestinal viability (see Part II notes).The more accurately the patient is assessed preoperatively, the better prepared the surgeon will be for the procedure. Also, accurate, efficient operative evaluation of the patient is critical for a successful surgical outcome. Involved segments of the intestinal tract should be exteriorized and isolated from the peritoneal cavity prior to incision. Laparotomy pads or huck towels are used to "pack off" the exteriorized segment to minimize intra-operative contamination and to improve accessibility. All segments except the caudal duodenal flexure and the ileocolic junction are usually readily exteriorized in the dog and cat.
Probably the single most important principle of intestinal surgery is the minimization of tissue trauma. Patient morbidity is reduced whenever tissue trauma is minimized. Factors which are important in minimizing tissue trauma include: atraumatic occlusion of the intestinal lumen, limited manipulation of the intestinal tract, stay suture placement, proper selection and use of instruments, and keeping tissues moist. Atraumatic occlusion of the intestinal lumen is best accomplished by digital occlusion by an assistant, although Doyen intestinal forceps or Penrose drain tubing may be effective alternatives. Minimizing manipulation of the intestine is accomplished by avoiding grasping the intestine with any surgical instruments, including thumb forceps. Instead, the tips of the closed thumb forceps are inserted into the intestinal lumen, the tips are allowed to spring open, and the wound edge is stabilized by the open tips of the thumb forceps. Stay suture placement also reduces the need for manipulating the intestinal tract, especially during resection/anastomosis. Proper selection and use of instruments during intestinal surgery involves the use of scalpel blades to incise rather than scissors, the atraumatic stabilization of the intestine with thumb forceps during suturing, and the use of suture with appropriately-sized swaged taper point or tapered cutting edge needles. If scissors are used on tissue (e. g., excision of everted mucosa), use sharp Metzenbaum scissors. Also, prevent tissue desiccation by regularly using warm, sterile isotonic solution on exposed tissues.
Intra-operative contamination is minimized by the following techniques: exteriorizing and packing off involved segments of the intestinal tract, using stay sutures to assist closure, occluding the intestinal lumen prior to incision, and decompressing affected areas of the intestinal tract prior to incision. Blood supply to the digestive tract is preserved by minimizing tissue trauma, appropriately placing ligatures, and locating incisions properly. Preservation of blood supply is an obvious prerequisite for successful intestinal surgery. Maintenance of an adequate lumen is essential for long-term function of the intestine. Factors which help maintain an adequate lumen include: minimizing tissue trauma, accurate apposition of tissue layers, and using approximating suture patterns rather than inverting, everting, or crushing patterns.
A secure closure of an intestinal incision is achieved by suture incorporation of the submucosa. The only reliable technique for incorporating submucosa is to place full thickness (i.e., lumen-penetrating) sutures. Tension across the suture line, particularly a circumferential suture line, will result in luminal reduction and is to be avoided. Adequate mobilization of tissue is necessary to avoid tension across the incision. Adequate mobilization is particularly important when performing surgery on the relatively fixed portions of the intestine (caudal duodenal flexure and ileocolic junction). More tissue may need to be resected in these areas to minimize tension across the anastomosis. Suture line protection is particularly important in potentially compromised patients. Two techniques are available: greater omental coverage and serosal patch (see below). Greater omental coverage should be provided routinely after closure of an intestinal incision, while a serosal patch is usually reserved for more at risk incisions.