Chapter 6 General Laparotomy
INTRODUCTION
No amount of technical expertise trumps careful preoperative planning. Strategies to avoid traumatic entry into the peritoneal cavity, preoperative determination of the need for mechanical and antibiotic bowel preparation, choice of incision, and planning optimal exposure are as important as intra-operative technical judgment and facility with the instruments. In some cases, the surgeon may have weeks to contemplate these issues, whereas in more urgent situations, such as frank peritonitis, ruptured viscus, leaking aneurysm, or trauma, the planning stage is significantly truncated. Patients who have had prior abdominal surgery or exposure to radiation, in particular, require extensive contingency planning by the operating surgeon. Previously radiated patients may be particularly unforgiving of operative misadventure because radiation may impede repair mechanisms and both the cellular and the vascular phases of wound healing.1
Detailed knowledge of embryology and anatomy begets well-vascularized incisions and tension-free, well-perfused anastomoses. For example, a surgeon familiar with the trajectory of counterclockwise midgut rotation about the superior mesenteric vessels during the second trimester of gestation2 can draw on the knowledge to reverse the process at operation to facilitate tension-free low pelvic anastomosis of the colon (Fig. 6-1) or to expose the lateral retroperitoneum in the avascular planes described by Cattell, Braasch, and Maddox and associates (Figs. 6-2 and 6-3).3,4
Some have advocated avoidance of midline incisions because of controversial concerns related to structural weakness and attenuated blood supply. Evidence supporting these misgivings is not convincing in studies in animals or humans, but transverse incisions may have other advantages. Sometimes, selecting a low transverse incision over a midline incision extending more cephalad will favorably affect pulmonary toilet and maintain functional reserve capacity without compromising intraabdominal exposure. The right lower quadrant (RLQ) transverse incision, for example, both allows for optimal operative exposure and facilitates pulmonary toilet in resection of cecal cancers. In the upper abdomen, transverse incisions can facilitate open packing or repetitive entry, as when multiple sequential laparotomies are required for the débridement of pancreatic necrosis. A once-common belief that muscle-dividing transverse incisions or muscle-reflecting paramedian incisions convey additional strength solely because of their multiple separately closed fascial layers or superior blood supply is also unsupported by experimental or clinical evidence. Indeed, a contradicting body of evidence supports the superiority of mass closure over layered closure even in areas off the midline, where multiple fascial layers exist (Fig. 6-4).5
In circumstances in which the pathology is confidently delineated by a preoperative history, physical examination, and/or preoperative imaging studies, it may be preferable to use one of a number of anatomically defined “specialty” incisions. Examples are the right subcostal (Kocher) incision for open cholecystectomy and duodenal exploration, the muscle-splitting RLQ incision for appendectomy, and the Pfannenstiel incision for nonmalignant gynecologic pathology.
Incorrect Choice of the Muscle-Splitting Appendectomy Incision
• Consequence
• Repair
• Prevention
Incorrect Choice of the Pfannenstiel Incision
• Consequence
• Repair
Failure to Consider the Consequences of an Incision’s Innervation and Blood Supply
• Consequence
• Repair
Failure to Anticipate Malignant or Nonmalignant Adhesions when Making the Abdominal Incision
• Prevention
Failure to Identify the Peritoneal Cavity
• Prevention
Once a small entry has been made into the peritoneal cavity, the operating surgeon should insert his or her finger and palpate the parietal peritoneum in the direction of intended incisional extension, in order to see whether the incision may be atraumatically developed in that direction. If free of adhesions, the incision can then be enlarged with the electrocautery, dividing all layers of the abdominal wall simultaneously rather than in sequence. In the case of previous laparotomy, hernia, inflamed abdominal viscera, enterocutaneous fistula, or adherent tumor, the laparotomy incision should be developed under direct vision and only as far as the first intraperitoneal adhesion. At this point, Kocher clamps should be placed to elevate the fascial edges of both sides of the incision so that loops of bowel adherent to it might be visualized. For initial dissection, after careful fascial division, an area is typically chosen in which the adhesions are translucent because a pocket of air or fluid has collected beneath them and their associated loops of intestine, signaling the absence of other viscera at risk beyond them. Translucent adhesions may be taken down sharply, and the free abdominal cavity may be thus visualized and entered (Fig. 6-9). For the same reason that spreading with the scissors is not desirable in entering the peritoneal cavity, minimal spreading is often best in the early development of the laparotomy. With traction provided by Kocher clamps in the vertical direction, the operating surgeon can often, with the aid of a Mikulicz pad held by the “clawed” nondominant hand, apply atraumatic tangential traction to the adhered loop of bowel, thereby permitting identification of interloop adhesions or adhesions of bowel to abdominal wall. The adhesions are maximally exposed and lengthened by this maneuver, and lysis can occur with sharp dissection as the fingers of the surgeon’s nondominant hand subsequently shift into the free space thus created (Fig. 6-10).
Lysis of adhesions is a shared and dynamic responsibility between the operating surgeon (often positioned on the patient’s right and lysing adhesions to the left of midline) and the first assistant (often positioned on the patient’s left and lysing adhesions to the right of midline). Assuming right-handed dominance and these positions at the operating table, the operating surgeon is best positioned to lyse adhesions in the epigastric midline and the first assistant is optimally positioned to lyse adhesions in the pelvis. For this reason, in pelvic operations, the surgeon stands on the patient’s left side. Although it is tempting to identify and “chase” interloop adhesions deep into the peritoneal cavity, a focused determination and a synergistic cooperative strategy should be formulated between first assistant and operating surgeon to first identify and free the entire underside of the parietal peritoneum and to develop the entire length of the contemplated abdominal wall incision before deeper intraabdominal pathology is addressed.
Injury to the Intestine
• Repair
Full-thickness small bowel injuries are handled differently than full-thickness large bowel injuries. In general, independent of whether the bowel has had mechanical or antibiotic preparation, most small bowel injuries may be handled with simple repair or resection and repair with anastomosis; uncomplicated full-thickness large bowel injuries in unprepared intestine should, generally, be handled with simple repair if they are solitary and if minimal fecal contamination has occurred. When possible, intestinal injuries should be closed transversely to minimize the likelihood that the repair would “hourglass” or narrow the caliber of the involved viscus. The Heineke-Mikulicz pyloroplasty6 gives good evidence that even when a rent is absolutely and deliberately longitudinal, most enterotomies can be closed transversely.
• Prevention
Adhesiolysis with the No. 10 blade should not be attempted by the novice surgeon because it requires a delicate touch and considerable experience with the texture and spectrum of abdominal adhesions. Frequent blade changes are necessary for effective use of the technique because it is the knife’s tip, rather than its belly, that incises the adhesion. The tip of the blade should be placed at the position of intended initiation of the adhesiolysis and rotated counterclockwise to form a large acute angle with the intended direction of incision. The knife should then be dragged to the right, maintaining this acute angle as the adhesion is lysed. The largest acute angle of blade with trajectory permitting the knife to be moved in the intended direction should be chosen and maintained as the blade is moved (Fig. 6-12). Smaller angles will increase the likelihood of bowel injury.
Visceral Injury during Exposure of a Ventral Hernia Defect
• Prevention
In either mobilizing a hernia sac or identifying the serosal surface of an externalized viscus during stomal reversal, blunt dissection is the surgeon’s friend. For ventral hernias, the sac is exposed after careful incision of the skin and subcutaneous tissue. The gloved hand invaginated into a Mikulicz pad strips the subcutaneous fat away from the sac to allow visualization of the sac’s origin at the disrupted fascia of the abdominal wall. Three approaches to safe repair are possible. For hernias in which incarceration is not suspected, some surgeons prefer to bluntly develop the plane between the abdominal wall’s musculature and the sac’s parietal peritoneum without ever entering the peritoneal cavity. They then close the muscular wall extraperitoneally. Other surgeons prefer to identify a point in the sac at which the viscera are not believed to be adherent to the peritoneum. They open the sac in that region, dissect the omentum or hollow viscus away from the parietal peritoneum, resect the sac, and then close the defect. A third option is to open the peritoneum only after circumferential identification of the sac’s interface with the fascial ring is complete (Fig. 6-13). In the latter two instances, safe entry into the peritoneal cavity is pursued with adhesiolysis as described previously for recurrent laparotomy.