Chapter 6 General Laparotomy
INTRODUCTION
Conviction that one should undertake only an invasive procedure whose complications one can manage is a fast-fading tenet as increasing numbers of nonsurgical specialists attempt invasive procedures. The granting of privileges in abdominal surgery, however, still assumes that the individual so honored will be able to plan an approach, accommodate to the sequelae of previous abdominal surgery, enter the abdomen, accomplish the intended task, repair or otherwise manage injuries created while doing so, deal with the sequelae of inflammation, treat infection, and deliver postoperative care with minimal assistance.
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
Figure 6-1 A, In the second trimester of embryologic life, the cecal bud migrates 270° counterclockwise from a position in the left lower quadrant to ultimately assume its characteristic anatomic position in the right lower quadrant. The superior mesenteric artery serves as the axis of this rotation. Because the aortic blood supply from which the colonic vessels ramify is in the midline, the rotation leaves the gutters themselves avascular. The white line of Toldt represents the avascular plane for incision and is the anterior confluence of the colonic visceral peritoneum with the parietal peritoneum of the lateral abdominal wall. B, When a segment of the left colon is removed, embryologic rotation is reversed to allow the proximal end to be brought into tension-free apposition to the distal end for anastomosis.
Figure 6-2 The maneuver developed by Cattell and Braasch for right medial visceral rotation takes advantage of the avascular right colonic gutter in mobilizing the colon so that the surgeon might inspect the retroperitoneal structures behind it.
Figure 6-3 The Maddox maneuver takes advantage of the avascularity of the left colonic gutter to rotate the left colon medially to allow inspection of the retroperitoneum on the left side of the abdomen.
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
Figure 6-4 The difference in suture placement between individual closure of the fascial layers and mass closure in a midline incision.
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
Figure 6-5 The muscle-splitting appendectomy incision is notoriously strong and seldom develops a hernia because the three lateral muscles—external oblique, internal oblique, and transversalis—are opened in different directions. When operative findings dictate that this incision be enlarged, however, the direction of the muscular incision in the external oblique and internal oblique musculatures must be altered slightly as the incision is extended medially across the rectus sheaths. If only a small extension is required, the rectus muscle itself may be able to be spared and retracted medially as the anterior and posterior sheaths are incised. Full-thickness retraction of the three muscle layers with vectors of force at 90° to the axis of intended extension will facilitate the alignment of the three layers as medial extension proceeds.
• Prevention
Incorrect Choice of the Pfannenstiel Incision
• Consequence
Figure 6-6 In the case of the Pfannenstiel incision, the cosmetically desirable low transverse skin incision is placed at right angles to the midline fascial incision. Whereas the skin incision may be lengthened to accommodate upward extension of the fascial incision, at some point, it may have to be abandoned or converted to an inverted T incision to accommodate the disparity in directions. For this reason, “specialty” incisions should be selected only when the pathology is well-defined preoperatively.
• Repair
Failure to Consider the Consequences of an Incision’s Innervation and Blood Supply
• Consequence
Figure 6-7 The intercostal nerves course obliquely in the abdominal wall, as shown. Thus, upper abdominal incisions traversing multiple nerve levels cause sensory and motor deprivation to the skin and muscles inferior to the incision. When the incision is bilateral, the denervation atrophy of the lower abdominal musculature may result in an undesirable loss of muscle tone. A bulge may occur without overt herniation.
• Repair
Failure to Anticipate Malignant or Nonmalignant Adhesions when Making the Abdominal Incision
An abdominal scar should alert the surgeon to the potential for intraabdominal adhesions caused iatrogenically or in response to the original pathology. The abdominal surgeon should be aware of any existing muscular defect in an area of intended incision as well as whether prosthetic mesh has been previously placed to repair a defect of the abdominal wall. Adhesion of the viscera to the abdominal wall in these circumstances, and in the case of tumors close to the anterior abdominal wall, should be presumed.
• Prevention
Small incisions reduce, and may compromise, exposure. In the case of malignancy, a longer incision may preserve the opportunity for en-bloc resection. Incisional planning for removal of large tumors or the extirpation of pathologically enlarged organs can be facilitated by abdominal palpation after anesthetic agents have relaxed the abdominal wall, thereby avoiding incision directly into the tumor or its parietal peritoneal attachments. The surgeon should not forego this one last opportunity for the physical examination to inform incisional planning.
Failure to Identify the Peritoneal Cavity
• Prevention
Figure 6-8 Lateral traction of the divided skin and superficial subcutaneous fat in obese subjects allows identification of the midline through observation of the midline subcutaneous fat, whose cross-hatching strands identify the linea alba.
Independent of the choice or direction of incision, the anterior surface of the parietal peritoneum is often fused to the deepest layer of fascia. Thus, the safest entry into the peritoneal cavity is with a knife. The surgeon and first assistant should elevate the peritoneum with toothed forceps; peritoneal entry is made with the belly of a No. 10 blade. Although compelling reasons of hemostasis, economy of time, and surgeon experience might suggest division of the muscle layers with the electrocautery, with rare exception, the initial entry into the peritoneal cavity should be made with cold steel. Even the unfortunate surgeon who finds that an incision intended only for the peritoneum has also entered a loop of intestine will be gratified at the time of repair that she or he has cleanly incised, rather than burned or spread, her or his way into the intestine.
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).
Figure 6-9 Kocher clamps applied to the divided fascia of a wound should be retracted at 90° to the body; the nondominant hand of the operating surgeon should be fanned over a Mikulicz pad; and gentle traction should be applied tangentially. The adhesions will thus be maximally lengthened and exposed under controlled tension, with less likelihood of traumatizing the bowel.
Figure 6-10 The first assistant presents adhesions to the operating surgeon in such a way that there is a “curtain” rather than a “tent” of bowel as the operating surgeon applies tension. In this manner, avoidance of a traction tear on the apex of the tent or accidental amputation of the bowel when lysing pointed adhesions will not occur.
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
Partial-thickness injuries usually need not be repaired. However, in the presence of severe adhesive disease, prior radiation, hematoma, or other comorbidity compromising repair, the relative paucity of a normal blood supply may cause a partial-thickness injury to evolve to a full-thickness injury in the postoperative period.
When a loop of bowel is injured, it is tempting to react immediately by attempting to place sutures or Babcock or Allis clamps to stem the flow of enteric contents. However, even atraumatic clamping of a partially defined enterotomy often helps very little and sometimes induces further trauma. Rather than close the enterotomy in an adhered loop of bowel in situ, the loop should be freed from adjacent structures, mobilized for complete inspection, and assessed for its salvage potential. Mobilization may demonstrate significant bowel injury or devascularization. A temporizing “damage control” approach, with temporary suture or stapling of the bowel, or division of the bowel with subsequent reassessment, may well be appropriate, but only after mobilization. To commit to definitive repair, resection, and/or anastomosis at the time of injury, before mobilization, or before the goals of the operation have been achieved has the potential to waste time; the initial closure may be inadequate or multiple injuries in the same short segment of bowel may be identified and need to be handled by incorporation of several injuries into a single resection.
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.
Whereas patient, unhurried dissection along the antimesenteric surface of the small intestine is often successful in freeing even the densest of adhesions, in some circumstances, it becomes abundantly clear that a loop of small intestine diving into the pelvis will not be able to be freed under direct visualization. In operations for intestinal obstruction, this situation is heralded by a dilated loop diving into the pelvis adjacent to an unobstructed loop coming out of the pelvis. When this circumstance exists, and when injury to such bowel in freeing it is judged to be inevitable, the appropriate goal is to expeditiously resect as short a segment of intestine as is possible, while preserving and minimizing injury to the structures to which the involved loop is adhered. To commit to the tedious freeing of such a loop in the hope of salvaging it is a fool’s errand; it often proves to not be possible, and the futile attempt wastes a significant amount of operating time. When small bowel resection is judged to be inevitable in adhesive disease, the afflicted loop should be delivered into the upper abdomen by the least traumatic means possible, and an assessment should then be made as to whether repair or resection with anastomosis is most appropriate. When the afflicted loop is attached to tumor and en-bloc resection is contemplated, the loop adherent to the tumor is isolated and left in situ for future mobilization with the specimen, and fecal continuity is restored by anastomosis of the two functioning ends of the bowel thus freed from the tumor.
• Prevention
Figure 6-11 Once a translucent area in the adhesive curtain is identified and developed, the index finger of the nondominant hand can be “hooked” around the remaining adherent loops of bowel, and they can be freed. The operator’s nondominant index behind the bowel both provides traction and ensures the operating surgeon that additional loops of bowel are not adherent.
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.
Figure 6-12 A and B, In lysis of adhesions using a scalpel, the tip of the No. 10 blade engages the adhesion. The largest acute angle that will allow the knife to cut while being dragged in the intended direction of the lysis is chosen. C, Smaller acute angles risk injury to the bowel.
Lysis of adhesions is among the most sophisticated tasks performed by the abdominal surgeon, and no preconceived time should be allotted for its completion. Extensive adhesions demand extensive patience and meticulous dissection. When dense adhesions are anticipated, no competing commitments on the surgeon’s time should be made. When adhesions are encountered unexpectedly in the course of dissection, arrangements should be made for all competing commitments to be rescheduled to minimize the risk of bowel injury. The first assistant should provide the operating surgeon with as panoramic a view as the anatomic situation permits. Success is often less the result of heroic traction than of an assessment as to how the bowel can be manipulated to best display the desired incisional plane.
Visceral Injury during Exposure of a Ventral Hernia Defect
• Prevention
The techniques for safe subsequent laparotomy, as described previously, may be adapted to permit definition and exposure of ventral hernias. An incision is begun at some distance from the palpable hernia sac in order to avoid entry into a peritoneal sac apposed to the skin. As the hernia occupies space in the subcutaneous tissue that is vacated after repair, incorporating an overlying ellipse of skin at the beginning of the operation serves three useful purposes. The maneuver minimizes the timeconsuming need for dissection of the sac from the overlying and often attenuated skin, which is often subsequently discarded. Improved visibility created by wider exposure enhances the surgeon’s ability to define the sac’s interface with the fascia and to avoid visceral injury. Finally, resection of redundant skin and subcutaneous tissue acknowledges the new geometry of the wound and the absence of a visceral bulge after fascial repair, thereby minimizing the magnitude of the skin flaps and making seroma formation less likely.
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.
Figure 6-13 A, After skin incision and exposure of the fascia of the abdominal wall, definition of the ventral hernia sac is achieved by blunt dissection in the subcutaneous space with a Mikulicz pad. B, Keeping the peritoneum of a broad-based hernia sac intact, a subfascial plane is developed to allow primary closure of the musculofascial defect or the attachment of prosthetic mesh. This technique is not suitable for situations in which incarceration is suspected or for narrow-necked hernia sacs. C, Some surgeons enter the sac in an area where the viscera are not believed to be adherent before the sac is fully exposed to the level of its interface with the fascia of the abdominal wall. D, Alternatively, the sac is completely exposed, and the surgeon enters at its interface with the fascial ring. E, Repair of the fascia is accomplished with either primary closure or subfascial implantation of prosthetic mesh circumferentially anchored to healthy fascia.
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