Goal of Laparoscopic Pancreatic Necrosectomy

The dogma surrounding the surgical treatment of acute pancreatitis has undergone significant revision as experience and knowledge have emerged to suggest that delaying and performing less surgery, even in cases where disease is severe, is considered to be safe and often effective.1 The current standard of care in treating acute pancreatitis has been outlined by the International Acute Pancreatitis (IAP) guidelines2 where conservative management of sterile necrosis is recommended, whereas in cases of infected necrosis, debridement or drainage is advised. Highly experienced centers no longer necessarily adopt the dictum that it is necessary “to remove all areas of necrotic tissue including necrotic pancreatic tissue and any infected necrotic tissue.”2 While it may be necessary to do so in certain cases, it is becoming increasingly clear that an expectant “step-up” approach to debridement and drainage may be a more appropriate strategy to reduce inflammation and eliminate microbial burden. With improvements in imaging, repeated percutaneous drainage with advancing size catheters, and increasing confidence that expectant observation may improve long-term outcome compared to more aggressive open surgical debridement, approaches to more completely debride pancreatic and peripancreatic tissue via smaller incisions have emerged. The minimally invasive approach to debridement offers the benefit of maintaining the compartmentalization of the infection focus while reducing microbial burden without contaminating virgin tissue planes and the larger peritoneal cavity. Avoidance of full abdominal exploration may reduce fistulas, bleeding, and wound complications that are associated with open explorations and commonly required multiple re-explorations. The goals of laparoscopic intracavitary pancreatic necrosectomy are to evacuate as much necrotic and infected tissue in a safe manner while creating a minimal access portal of entry into the necroma that can be maintained for as long as needed to perform repeat debridements. This approach departs from the surgical instinct to completely debride all infected tissue with a single operative intervention and offers the benefit of less bleeding and systemic inflammation with the opportunity to re-image and rethink the surgical strategy.

Image-Guided Catheter Drainage: The First Step

Although initially met with skepticism, percutaneous drainage of infected pancreatic necrosis has been achieved in selected cases with complete resolution of infection. While it seems counterintuitive that large particulate matter can be effectively controlled and evacuated by percutaneous drainage alone, in some patients the enzymatic breakdown of the necroma produces liquefied contents which can be successfully evacuated through the catheter. This process is aided by the appropriate antibiotic selection and penetration into the infected tissue. As early as 1984, attempts at image-guided catheter-based drainage were reported.3 In 1998, Freeny et al. published a series of patients with infected necrosis treated by computed tomography (CT) guided drainage.4 In their series of 34 patients, 26 out of 34 (76%) patients had clinical improvement with catheter drainage, and 16 out of 34 (47%) had complete cure measured by resolution of necrotic collection with catheter drainage alone. This series notes the frequent requirements for catheter upsizing or exchange (four per patient) and frequent irrigation required in order to maintain catheter patency in the face of the thick contents of the necroma. Steiner et al. published a similar series the same year of 25 patients treated with CT-guided drainage of pancreatic necrosis.5 Of the 18 patients treated primarily by interventional radiology (IR) drainage, 14 (77%) experienced clinical improvement with catheter drainage and eight (44%) were “cured” by drainage alone. Based on these and other reports, it seems logical that the first step in the expectant treatment of infected pancreatic necrosis is to obtain adequate percutaneous image-guided drainage of major sites of visible necroma formation, to culture all draining material and to follow the clinical course of the patient to assess the need for catheter upsizing or surgical debridement. With experience, the timing of early laparoscopic debridement will be balanced against repeated percutaneous drainage, upsizing, and imaging. The timing of each approach must be individualized to the clinical course of the patient and the experience of the managing surgeon. As the technique and instrumentation develop around laparoscopic necrosectomy, it is anticipated that early definitive minimally invasive debridement will reduce the need for repeat imaging and shortened length of stay.

History of Direct Visualization Minimally Invasive Pancreatic Necrosectomy

There have been essentially three techniques of direct visualization minimally invasive pancreatic necrosectomy described over the last 10 years. The first technique involves making a posterior incision to enter the retroperitoneum and directly visualize the space with a nephroscope or similar type instrument. Single or multiple access site incisions can be used and repeated drainage achieved. Second, “traditional” (intraperitoneal) laparoscopy has also been described whereby pneumoperitoneum is established and the retroperitoneum is entered, usually via an opening in the transverse mesocolon or gastrocolic ligament. With direct opening of the necroma, several ports are used to debride, irrigate, and lavage the abdominal cavity. The final and third approach, which is our preferred approach, is to percutaneously enter the necroma cavity extraperitoneally and evacuate fluid and tissue using conventional laparoscopic equipment. We term this approach laparoscopic intracavitary pancreatic necrosectomy (Lap-ICPN).

In 2000 Zhu et al. published a series of ten patients with severe acute pancreatitis that underwent “traditional” laparoscopy (with pneumoperitoneum) and debridement of necrotic pancreas.6 After lavage with sterile saline, large bore catheters were placed, and postoperative lavage was continued for 7 to 14 days. While this was the first description of “conventional” intraperitoneal laparoscopy for pancreatic debridement, it must be noted that these patients were operated within days of presentation of severe acute pancreatitis. Parekh reported in 2006 on a series of 18 patients7 that underwent similar “conventional” laparoscopic debridement using a “hand assist” port. Two patients (11%) died, two (11%) required subsequent “open” debridement, and two (11%) required repeat laparoscopic intervention.

Intracavitary Debridement

In 2000, our group reported the first description of the intracavitary approach to necroma debridement using conventional laparoscopic equipment.8 Immediately following this report, Carter, McCray, and Imrie described a series of ten patients using a similar technique of image-guided catheter placement and dilation of the tract to establish a direct access to the necrotic cavity.9 This latter group used nephroscopic and endoscopic instruments to perform irrigation and debridement and the use of postoperative continuous lavage instead of closed drains. In 2001, Horvath et al. described the results for six patients using a similar technique, this time with two ports to allow for irrigation and debridement under direct visualization.10 Again, image-guided catheters were used to temporize patients via drainage of collections; if further debridement was deemed necessary, patients were taken to the operating room where two 10-mm trocars were placed via a flank incision using the image-guided catheters as guides. More recently, Bucher et al. described a single port technique in eight patients.11 A single 12-mm trocar was placed over a previously placed drain (either postsurgical or image The Society for Surgery of the Alimentary Tractguided) and using a single 12-mm port, 5-mm instruments were used under direct visualization with a 5-mm laparoscope via the same port. A jet lavage/irrigation was again used along with blunt graspers to remove as much solid necrotic tissue as was deemed safe. On completion, a two channel drain was used for continuous postoperative lavage.

Although many excellent reviews of the various series of minimally invasive pancreatic necrosectomy have been recently published, comparative trials are still lacking.12,13 Table 1 lists the complication rates, requirement for open laparotomy (or re-laparotomy), and mortality rates for selected studies of both minimally invasive and traditional open techniques.

Table 1 Major complications are defined according to the original reference and have not been standardized
Full size table

Terminology

A brief note on terms and definitions is warranted. These techniques have been referred to as laparoscopic, nephroscopic, endoscopic, or visually assisted retroperitoneal debridements.12,14 We prefer the term “minimally invasive intracavitary pancreatic necrosectomy” because it emphasizes the benefits these techniques offer. “Minimally invasive” techniques offer smaller incisions, less pain, more rapid healing, and most importantly potentially incite less of an inflammatory and catabolic response than a large open incision. “Intracavitary pancreatic necrosectomy” emphasizes the fact that this technique allows direct access to the necroma cavity with minimal disruption of normal tissue planes or seeding of healthy tissue with infected, necrotic debris.

Technique of Intracavitary Pancreatic Necrosectomy

The steps and goal of Lap-ICPN, in accordance with the IAP guidelines,2 are to access the pancreatic necroma cavity safely and evacuate as much material as possible. The goal should be to perform this safely with the expectation that repeat imaging along with repeated assessment of the clinical course will dictate the need for additional debridement. In many cases, multiple cavities connect via small channel loculations. This becomes apparent with subsequent debridements where the irrigation of one cavity results in necroma effluent exiting a seemingly remote cavity. As the necroma liquefies and the channels connecting the retroperitoneal cavities become unobstructed, irrigation can proceed once large bore (i.e., 32-French) drainage tubes have been placed into the various cavity sites. Despite the concern for lavage or insufflation-induced translocation of bacteria from infected necrosis into the systemic circulation, we have not witnessed an exacerbation of the septic response in any of the cases we have performed to date. This may be because of patient selection which invariably involves patients in the late course (3–6 weeks) of pancreatitis when the acute inflammatory response is quiescent and the necromas have demarcated and compartmentalized. However, before proceeding with Lap-ICPN, it is important to verify that antibiotic schedules are fully accounted for and that adequate antibiotic prophylaxis is present at the time of surgery. As the pancreatic necromas are most often deep below the anterior abdominal wall surface, percutaneous, image-guided access is achieved via a flank approach with catheter placement. It is often the case that lateral flank drains on the opposite site of the abdomen are present. To complete a dual cavity procedure, positioning may require very wide draping. Alternatively, one can complete the first side and re-drape for the second. In most cases, Lap-ICPN is performed 1–3 weeks following image-guided percutaneous drainage. With already well-demarcated and compartmentalized cavities at the time of clinical presentation, we have performed the procedure as soon as 2 days following IR drainage.

Accessing the Cavity

The drains used by IR are often the pigtail variety that are fenestrated and open ended with a nylon looped configuration to maintain the pigtail curl, thus preventing dislodgment. These drains can be easily accessed using the appropriate gauge guidewire. Depending on the level of experience and expertise, guidewire access to the necroma cavity can be obtained with or without fluoroscopic guidance. We prefer to use a special guidewire whose end is flexible and soft for at least 40–60 cm allowing it to curl repeatedly within the cavity. Under fluoroscopic visualization, this allows the operator to gain a sense of the size of the cavity to be entered. The wire should be reasonably inflexible below the curled end as the multiple layers of the abdominal wall can be difficult to traverse with the laparoscopic trocar. Often, the percutaneous IR-placed drains are very close to the rib cage, which can present a challenge. Once the wire is securely positioned, a laparoscopic trocar is placed over the wire using fluoroscopic guidance, being careful to avoid angulation of the wire and a smooth transition of the trocar into the cavity. A skin incision is used to extend the wire entry site and we begin with a 5-mm smooth trocar. Once we verify that the trocar is within the cavity, we next gently admit the 5-mm laparoscopic irrigation/suction device into the cavity to remove the liquid debris. We next verify that we are within the cavity by using a 5-mm 0° laparoscope and gentle insufflation. Once proper location in the necroma is established, we then place a laparoscopic kitner into the cavity via the 5-mm trocar to use as a stylette for removal of the 5-mm trocar and placement of the 15-mm trocar. This is completed under fluoroscopic control if needed. Once the cavity is accessed, we then again verify that we are within the cavity by performing a laparoscopy with insufflation. Once the cavity is entered with the 15-mm trocar, we essentially use three techniques to clean out the necroma cavity and fully debride all of the tissue (see Fig. 1).

Fig. 1
figure 1

a A patient is prepped and draped with IR drain shown in left upper quadrant (LUQ). b Using the Seldinger technique, a guidewire was inserted into the necroma through the IR drain. The drain was removed over the guidewire and the laparoscopic port was placed into the necroma over the guidewire

Full size image

Debridement Maneuver

Initially, we do not use insufflation but rather remove the seal on the “cap” of the trocar and using both the 5-mm 0° laparoscope with either the suction/irrigator or a 5-mm grasper, we remove large pieces of necroma under direct visualization at the immediate base of the trocar. The assistant holds the trocar in place and moves it in a circular motion to visualize the greater expanse of the cavity (see Fig. 2).

Fig. 2
figure 2

a Debridement technique: the white seal on top of the port (dashed black arrow) has been removed and the 5-mm blunt grapser (solid black arrow) is being used to debride necrotic tissue under direct visualization with the 5-mm 0° laparoscope (white arrow.). b Debridement technique: the view of the contents of the necroma, without insufflation, from the laparoscope is shown. The blunt grasper (solid black arrow) is seen manipulating the necrotic tissue (dashed black arrow) at the base of the laparoscopic port. c Debridement technique: removing necrotic tissue (white arrow) using the blunt grasper (black arrow)

Full size image

Inspection Maneuver

Periodically, we will reattach the trocar head, insufflate, and inspect the entire cavity. In our opinion, it is best to perform the cavity necroma evacuation with a single 15-mm trocar not two trocars. With insufflation and the seal of the trocar, it is difficult to maintain pressure while inserting two 5-mm instruments through the valve. For this reason, we often just inspect during insufflation, maintain the position of the trocar at the site of heavy contamination and tissue accumulation, and remove the trocar head and continue using the debridement maneuver with multiple instruments operating co-axially using the 5-mm scope for direct visualization.

Irrigation Maneuver

Once we feel we have completed the debridement, we will use a jet lavage instrument inserted into the cavity and then we will irrigate the cavity with a high volume of saline. The trocar head is again off; the trocar can be placed at an angle which will allow the overflow effluent to pour into a receptacle by gravity and then jet lavage/gravity irrigation procedure is repeated while periodically using the “inspection maneuver” to monitor progress and direct further debridement or lavage.

It is often the case that pulsations in the projection of major arteries can be visualized during the procedure. If tissues are adherent to pulsatile structures, we avoid unnecessary debridement. In this case, a direct high-pressure irrigation often suffices (see Fig. 3).

Fig. 3
figure 3

Irrigation technique: the suction irrigator (solid black arrow) is used to irrigate the contents of the necroma

Full size image

Extent of Debridement

Keep in mind that at the termination of the procedure with placement of a large bore drainage tube (i.e., a 32-French red rubber catheter), repeat Lap-ICPN becomes relatively simple as a large tract is already established, and trocar access is easily facilitated. Repeated inspections under insufflation often demonstrate significant necrotic debris seemingly originating from a distant corner of the necroma cavity. This recess may actually be a channel leading to another necroma cavity. It is important to recognize that Lap-ICPN can be considered a staged procedure that in our experience, carries very little morbidity in terms of provoking an inflammatory response. Hemorrhage can occur during the procedure, and the operating team should always be prepared for rapid conversion. For these reasons, we tend to complete as much of a necrosectomy as is well tolerated and safe and plan for repeat exploration(s) as needed. Part of this success and low morbidity may be the timing of the procedure, temporizing with image-guided catheter placement, recognition that complete debridement may not be necessary, and the technique itself. Once the cavity has been irrigated and full cavity inspection during insufflation laparoscopy has been deemed adequate, we place a 32-French fenestrated red rubber tube into the cavity and use a 2-0 nylon to affix it to the skin. The second cavity (if present) can then be similarly approached. As we have mentioned previously, when clearing out the second cavity and performing high-volume irrigation, it is often the case that the two cavities have been discovered to communicate by effluent draining from one site to the other. In some cases, it is possible to flush the cavity out. Repeat imaging and repeated Lap-ICPN can often establish the degree of completeness of the necrosectomy and the anatomy of the necroma cavities.

Summary

Although direct prospective studies lag behind the ongoing developments in this technique, we anticipate they will be forthcoming as experience with this technique becomes more widespread. It is interesting to note that four separate groups, almost simultaneously, developed minimally invasive techniques to achieve direct access to the necrotic cavity using image-guided catheters as both a temporizing method as well as assisting in obtaining surgical access; these same studies emphasized the use of laparoscopic and pulse irrigation devices as effective means of debridement.9–12 These studies utilizing image-guided drainage as a temporizing measure provide further support for the “step-up” approach to managing pancreatic necrosis that is currently being evaluated in the PANTER trial.14 This ongoing multi-institution trial prospectively randomizes patients with pancreatic necrosis who fail conservative management to either:

  1. 1.

    “Step-up” approach to pancreatic necrosis, as defined by a progression from catheter drainage to video-assisted retroperitoneal debridement to open debridement if required.

  2. 2.

    Maximal open debridement as the initial intervention after failing conservative therapy.

This trial will allow a direct comparison of open debridement to “grouped” minimally invasive therapy at the discretion of the surgeon.