**7. Laparoscopic and open necrosectomy**

Although utilization of a drainage tract and the transgastric approach are important for management of pancreatic necrosis, traditional laparoscopic and open necrosectomy methods also continue to be utilized.

For laparoscopic necrosectomy, patients are typically placed in lithotomy position, with the operating surgeon standing between the legs. An umbilical port is placed first. Upon entering the abdomen, a diagnostic laparoscopy should be performed. Subsequently, two left lateral ports and an epigastric port are placed. In some cases, a hand-assist port is placed to augment dissection and removal of tissue. Following lysis of adhesions, a transgastrocolic, for pancreatic head or body necrosis, or transmesocolic, for pancreatic tail necrosis, approach to retrogastric necrosectomy can be taken (**Figure 2**). Upon entering the area of necrosis, blunt instruments are used to remove loose, necrotic tissue. This tissue is then placed into an endocatch bag for removal from the abdomen. Dissection is alternated with irrigation and suction to remove as much necrotic tissue as possible [40]. Once the necrosectomy is complete, large drainage catheters are placed in the cavity, which also allow for post-operative irrigation. At this time, consideration should also be given to cholecystectomy, if gallstones were implicated in the development of pancreatitis, and to nutritional access. Depending on the specific study, mortality for patients who require laparoscopic necrosectomy ranges from 10 to 18%. Rates of reoperation also vary widely, ranging from 11 to 38% [41, 42].

The most invasive procedure used for the treatment of pancreatic necrosis is the open debridement. This technique is reserved for patients that fail other less invasive techniques, or patients who require concurrent intervention for another intraabdominal process, such as bowel ischemia or abdominal compartment syndrome. Unless midline laparotomy is required for another indication, the abdomen can be opened with bilateral, subcostal incisions. The gastrocolic ligament is then opened, and the stomach is reflected superiorly, exposing the lesser sac (**Figure 2**). The transverse mesocolon is then opened, exposing the retroperitoneum. The hepatic and splenic flexures of the transverse colon are often taken down at this point. A Kocher maneuver may also be necessary if the area of necrosis involves the head of the pancreas. Once the pancreas is adequately exposed, blunt debridement can begin. This is usually accomplished with digital dissection or with lavage in order to minimize the risk of bleeding or bile duct injury. These risks must be balances with adequate removal of loose, nonviable tissue. Wide drainage of the area with a sumping tube (i.e. Abramson drain) can facilitate continue lavage and debridement. The quality of the initial necrosectomy predicts the need for subsequent operations.

After necrosectomy, the abdomen may be kept open, with packing in place, to allow for repeated removal of necrotic tissue. Alternatively, the closed packing technique can also be used. This technique consists of filling the cavity created by the necrosectomy with gauze-filled Penrose drains. The drains are removed one at a time, until the cavity closes [43]. A third option is continuous irrigation, where large catheters are placed into the lesser sac under direct visualization. Additional drainage catheters are left in the peritoneal cavity. The abdomen is then closed and the large catheters are used for continuous installation of hypertonic fluid [44].

As in patients who undergo laparoscopic necrosectomy, the rates of morbidity and mortality following open necrosectomy are high. Rates of post-operative morbidity range from 34 to 95% and mortality ranges from 6 to 47%, depending on the pre-operative severity of illness. Rates of reoperation vary depending on the packing technique. When the abdomen is left open, reoperation is planned rather than required because of deterioration or other complications, such as hemorrhage. Depending on the study, when the abdomen is left open, patients may return to the operating room from 1 to 17 time. Comparatively, relaparotomy is required in 17% of patients treated with closed packing require and 17–27% of patients treated with continuous irrigation. Rates of pancreatic fistula also differ depending on packing technique with a 25–46% rate in open abdomens, 53% rate in closed packing, and 13–19% rate with continuous irrigation [45].

The outcomes for both of these techniques are improved when intervention can be delayed at least 3 weeks. Delayed necrosectomy is associated with lower rates of exocrine and endocrine insufficiency, adverse post-operative events, including bleeding, and mortality [17, 46]. Early surgical intervention only provides a survival benefit in the case of decompression of abdominal compartment syndrome [47, 48].

When compared directly, in a retrospective case series, the rates of pancreatic fistula, post-operative pulmonary infections, and surgical site infections were all significantly lower with laparoscopic necrosectomy. Additionally, patients who underwent laparoscopic necrosectomy also had a shorter length of stay, but a longer initial operation. There was no difference in need for reoperation, overall morbidity, or mortality. It should be noted that mortality was very low compared to other literature in this study, 5.9% in the open group and 4% in the laparoscopic group [49].
