Karen M. Tobias, DVM, MS, DACVS
Professor of Small Animal Surgery, University of Tennessee College of Veterinary Medicine
Perform "clean" procedures first (i.e., liver and kidney biopsies before gastrotomy). Before opening viscera, set aside clean instruments for abdominal wall closure and isolate the viscera with laparotomy pads. Make sure that you keep contaminated and noncontaminated instruments separated. Do not touch the noncontaminated area of the instrument table with "contaminated" hands (i.e., once you've done the enterotomy, don't reach into the area where your closure instruments are kept until you change gloves, and don't lay these clean instruments down in an area where your contaminated hands and instruments have touched).
Liver biopsy: Guillotine technique: Encircle the tip of a liver lobe with a loop of 3-0 gut or other absorbable suture and slowly tie the loop to crush through the liver tissue and ligate the vessels. Add a second throw to tie a knot. With a scalpel blade, gently cut through the liver tissue distal to the knot. If the liver lobe is rounded, insert a needle lateral to the most prominent part of the curve, and about 0.5-1 cm from the margin of the liver lobe, and tie a throw, leaving the end of the suture long. Now take the long portion of the suture and tie to your original suture end, pulling the second throw about 1 cm lateral to the first. If you can't stop the second throw from sliding toward the first, pass a second needle through the liver tissue where you want the second throw to land, and tie lateral to it (or grab the wedge of tissue with an Allis forceps and tie lateral to that). For lesions in the center of the liver, use a skin punch and stuff the hole with gel foam, omentum, or a crushed piece of fat.
Pancreatic biopsy and partial pancreatectomy can be performed with a dissection and ligation technique or with a guillotine technique. Pass a suture loop (3-0 absorbable) around the end of one limb of the pancreas and tie tight to crush the tissues. Amputate the end to retrieve the biopsy specimen. To dissect, use a cotton tipped applicator swab or fine hemostat to separate between lobules. Use bipolar cautery or hemoclips for hemostasis (if you use suture, don't lift up when you ligate or the vessels will tear). Be careful not to compromise the blood vessels to the duodenum.
Gastrotomy: Isolate the stomach with moistened laparotomy pads. The gastric incision should be in a relatively avascular area, midway between the greater and lesser curvature and near the pylorus. Place stay sutures (2-0 PDS, Prolene, or gut) at both ends of the proposed gastrotomy site and clamp them. The assistant holds these clamps up and apart while the surgeon makes a stab incision. Incise through the gastric wall with a #10 blade and continue the incision with scissors. Examine the pylorus through the incision. Close the gastrotomy with 3-0 PDS in a Cushing pattern and oversew with a Lembert pattern. An easy way to put in a two layer closure is to tie the first knot at the beginning of the closure leaving the short end of the suture 2-3 cm long. Then perform a Cushing's pattern, followed by a simple continuous oversew (this will actually be a Lembert if the first layer is inverted), tying back to the first knot. If there is a lot of bleeding before gastrotomy closure, close the mucosa first with a simple continuous pattern, then close the outer 3 layers with 1-2 layers of inverting suture.
Intestinal biopsy: Milk intestinal contents away from the proposed biopsy site, and isolate with moistened laparotomy sponges. Insert a stay suture through the antimesenteric surface of the intestine; the suture bite will be about 4 mm in width and perpendicular to the long axis of the intestines. Lift up on the stay suture and cut along side of it, angling inward, into the intestinal lumen. Repeat on the opposite side of the suture so that a wedge of free, full thickness intestinal wall is left on the suture. Close with a Gambee pattern (usually about 3 sutures are needed) and wrap in omentum.
Intestinal anastomosis: Double ligate the mesenteric vessels to the resection area. With 3-0 suture on a curved needle, take bites around the mesenteric fat and slightly into the mesenteric wall of the intestines in the site where the intestines is to be transected, to ligate the remaining arcuate branches. Clamp the intestines with non-crushing clamps (Doyens) or occlude with umbilical tape or an assistant's fingers at least 5 cm back from the proposed sites of transection. Clamp the "throw away" sides with Carmalts. Isolate the area with moistened laparotomy sponges and transect the intestines. Placing the first sutures at the mesenteric side, begin a continuous Gambee pattern (or placed 2-3 interrupters here first).
Gambee: Pass the needle through all the intestinal tissues on one side. While lifting up on the needle, slowly back it out until it is pressing against the mucosa/submucosa junction (a white line) and pop the needle through (this leave mucosa under the needle and submucosa/musculari/serosa above). Pull the needle through. On the opposite intestines, use the needle to push the mucosa down into the lumen, then pop the needle through and out the full thickness of the intestines. Again, the mucosa will be under the suture, and when the two pieces of intestines are pulled together, the mucosa will be inverted into the lumen and the other 3 layers apposed. Complications after intestinal anastomosis with a simple continuous pattern are no greater than with interrupted patterns.
Linea closure: Why do dogs get incisional hernias after closure of laparotomies? In a very few, tension, excessive activity, or poor immune system may play a role. In most, however, it is a failure of the surgeon. What can we do to make closures faster or easier but still safe? The first is to clear the external rectus sheath of subcutaneous fat before opening the linea. In dogs, the subcutaneous fat attaches to midline, hiding the linea so that we miss it on the way in (causing an "off-midline" incision) and the way out (closure). After incising through the skin and SubQ, pick up the SubQ fat with thumb forceps on one side at the caudal extent of the incision. Make a small knick in the fat with your scissors, then insert one scissor blade in the knick. Push-cut as you run the scissors cranially to transect the fat's attachment. Repeat on the opposite side. This should expose the white shiny surface of the external rectus sheath, and make the linea visible.
During closure, a continuous pattern is as good or better than a simple interrupted pattern, as long as the knots are good and the bites get the external rectus sheath. Use an absorbable monofilament (PDS or Maxon) and make the bites at least 0.5 cm wide in most dogs. Take a wide bite at the top of the incision line and tie at least 5 throws, being careful to pull harder with your left (or nondominant) hand so that the throws comes done exactly over midline, and all throws result in the "short end" laying flat (versus sticking up perpendicular to the dog--a sure sign of half-hitching). Now, use your thumb forceps to pull the tissues flat toward midline (don't evert!) and take bites of only the outer white external rectus sheath (you don't need muscle or peritoneum--these provide no additional holding and may result in rectus sheath bites that are too small). Continue to the opposite end, then tie at least 6 throws to the loop. The loop end will want to hitch, so make sure the loop is at least 2 cm long, and make sure to pull harder with your left (nondominant) hand so that, with each throw, the loop lies flat and the throw comes down over the incision line. Continuous patterns cause less inflammation and are faster than interrupteds; follow these guidelines and failures will not be the surgeon's fault!
Anal sacculectomies are worrisome to many veterinarians because of the potential risk for incontinence, hemorrhage, infection, and fistula formation. Also, they're not as easy as the books seem to indicate! In reality, incontinence is very uncommon after anal sacculectomy, unless the dissection is excessively wide. Anal sacculectomies can be performed by closed or open techniques. Closed anal sacculectomies should always be performed on neoplastic sacs, or on ferrets (hopefully limiting the stench). In animals with anal sac rupture and local cellulites, systemic antibiotics and anti-inflammatories (i.e., NSAIDs) should be administered until swelling decreases. Abscesses should be opened, cultured, and lavaged, and can be left open to heal. Surgery is performed once acute inflammation has subsided.
Closed technique in dogs is usually facilitated by inserting something into the sac (wax, a Foley catheter, umbilical tape, hemostat, acrylic), unless there is a tumor in the sac wall. The animal is prepped and placed in a perineal position. In the dog, something is inserted into the sac to facilitate locating the tissue. An incision is made parallel to the anus over the sac. The sac is identified, and fibers of the internal and external anal sphincter muscles are dissected off the sac, staying directly against the sac to avoid vessel and nerve damage (especially medially). Ligate the duct at the mucocutaneous junction. After gland removal, inspect the area to make sure no mucosa is left. Flush the area if contamination has occurred. Appose the SQ and skin.
Open technique is easy to use in dogs; contamination is expected so prophylactic antibiotics and flushing are helpful. Some clinicians do not suture the SQ and skin; the wounds usually heal very rapidly with or without closure. Technique: One blade of a pair of sharp-sharp scissors is placed through the duct into the sac, and the scissors are closed, incising through the skin, SQ, external anal sphincter, duct, and anal sac. Grasp the edges of the anal sac (grey and shiny) with several hemostats. Dissect the sac free from the sphincter muscle fibers with scissors or a 15 blade. A finger can be inserted into the open sac and the blade scraped across the outside of the sac to break away fibers. The sac is removed and the SQ and skin are closed as for the open technique, or left open to heal by 2nd intention.
Complications of anal sacculectomy include draining sinuses, fistulas, and persistent infection from incomplete surgical resection; incontinence from caudal rectal nerve damage; intraoperative hemorrhage; and postoperative tenesmus and dyschezia from inflammation, stricture, or scar formation. If one caudal rectal nerve is destroyed, the sphincter will reinnervate in one month from the other side.