Pancreatic Pseudocyst Drainage Gordie K. Kaban, Richard A. Perugini, Donald R. Czerniach, and Demetrius E.M. Litwin

he management of pancreatic pseudocysts is a challenging clinical problem that has become multi-disciplinary, often involving the collaboration of surgeons, gastroenterologists, and interventional radiologists. Unfortunately, questions such as the timing and mode of intervention have yet to be definitively answered in clinical trials. What is clear is that the burgeoning field of minimally invasive surgery and interventional endoscopy has provided a number of alternatives to open surgical treatment. The lingering questions regarding optimal management and the growing number of therapeutic options are promising to make this an exciting, if not controversial period in the evolution of pseudocyst therapy.

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DEFINITION A pseudocyst by definition is a well localized, pancreatic fluid filled cyst, lined by a nonepithelialized surface.1 They are commonly found in a retro-gastric location within the lesser sac or in relation to the body or tail of the pancreas (Fig 1). Unusual locations, such as the groin2 and mediastinum have been reported, suggesting that any space communicating with the retroperitoneum or peritoneal cavity is subject to pseudocyst formation following pancreatic injury.

PATHOPHYSIOLOGY The current understanding of pseudocyst formation is based on the theory of an initial pancreatic insult, such as trauma or acute pancreatitis, which results in pancreatic ductal disruption.1 The surrounding adipose tissue and viscera undergo an inflammatory reaction in response to the liberated and activated pancreatic exocrine secretions. The resulting fibrous peel “walls off” the pancreatic secretions, creating a nonepithelialized cyst. In contrast, pseudocysts arising in the setting of chronic pancreatitis have a different pathophysiology. These pseudocysts are

From the Department of Surgery, University of Massachusetts Medical School, Worcester, MA. Dr. G.K. Kaban receives funding from United States Surgical Corporation. Address reprint requests to Demetrius E.M. Litwin, MD, Minimally Invasive Surgery Service, Department of Surgery, University of Massachusetts Medical School, Worcester, MA 01655. © 2004 Elsevier Inc. All rights reserved. 1524-153X/04/0601-0008$30.00/0 doi:10.1053/j.optechgensurg.2004.01.008

often associated with persistent ductal abnormalities and are less likely to resolve spontaneously.9

PSEUDOCYST VERSUS NEOPLASM The distinction between true cyst and pseudocyst is imperative especially if nonoperative treatment is planned. Pseudocysts constitute the majority of cystic lesions related to the pancreas. Nevertheless, approximately 10% of cystic structures are neoplastic in origin, supporting cyst wall biopsy before surgical drainage at laparotomy or laparoscopy.3 For this reason, asymptomatic, incidental pancreatic cysts, especially in the elderly, should not be dismissed as pseudocysts.4 This is a classic pitfall in the management of cystic lesions of the pancreas. Pseudocysts can occur with a wide frequency ranging from less than 2% to 70% following an acute episode of pancreatitis, and occur most frequently following alcoholic pancreatitis.6 The prevalence of pseudocysts has changed as definitions and imaging techniques have been refined. The commonly identified fluid collections seen by computed tomography (CT) following an episode of acute pancreatitis should not be mistaken for the less frequent, mature-walled pseudocyst.

NATURAL HISTORY Our understanding of the natural history of pseudocysts has been critically important in the development of management strategies but remains a controversial topic. Early surgical dogma mandated that pseudocysts greater than 6 cm in diameter or existing for greater than 6 weeks from the initial pancreatic insult undergo operative drainage.5 This was based on the perception that the risk of complications from pseudocysts during expectant management outweighed the surgical risks of drainage for cysts meeting these criteria. As experience grew, it became clear that neither the size, nor the age of the pseudocyst could be used as an absolute criterion for intervention.7,8 Although pseudocyst complications remain a concern with observation alone, spontaneous resolution of asymptomatic pseudocysts has been shown to occur in nearly 60% of patients managed nonoperatively.

INDICATIONS FOR INTERVENTION Most commonly, immature fluid collections are identified early in the course of acute pancreatitis and are followed

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Computerized tomographic scan of a large, thick walled pancreatic pseudocyst within the lesser sac.

serially by CT for resolution. If a pseudocyst develops in the course of observation and fails to resolve spontaneously, there are several indications for intervention. In general, the pseudocyst that is symptomatic, is enlarging by serial radiologic examination, or is found to be infected mandates drainage.6 Should the suspicion of infection arise, the cyst should be aspirated and infection confirmed by Gram stain and culture. Infected cysts identified following a well documented episode of pancreatitis that do not appear to contain appreciable amounts of debris should then undergo CT guided catheter drainage.10 The more common reason for intervention is the symptomatic pseudocyst. Complaints include persistent abdominal pain following an episode of pancreatitis, abdominal fullness, nausea, and weight loss. Mechanisms for the evolution of symptoms are quite variable, often relating to the location of the pseudocyst. Less common presentations include jaundice from obstruction of the biliary tree, obstruction of the gastrointestinal tract, rupture of the cyst into the peritoneum, or hemorrhage into the cyst cavity. Cyst size cannot be used as a sole criterion for drainage, however, larger cysts tend to be symptomatic and are therefore more likely to require intervention.7 Although there is little supporting data, several authorities have recommended intervention for any pseudocyst found to be increasing in size on serial radiologic evaluation.6,7

THERAPEUTIC MODALITIES There are four approaches to pseudocyst drainage once the need is recognized: open surgical, percutaneous, endoscopic, and laparoscopic.

Open Surgical Drainage Open surgical drainage by way of cyst-gastrostomy, -jejunostomy, or -duodenostomy, for a lack of alternatives, was the mainstay of treatment for many years. It remains a definitive treatment option, but has been usurped by less invasive modalities. Open surgical drainage remains the procedure of choice for the pseudocyst that is suspicious for neoplasm, the infected complex pseudocyst, and for failures or recurrences following other nonsurgical interventions.

Percutaneous Drainage Percutaneous drainage of pancreatic pseudocysts is presently indicated for the infected pseudocyst. Simple needle aspiration of pseudocysts is accompanied by a high recurrence rate.11 Drainage through an indwelling catheter can be remarkably successful but is fraught with potentially long periods of drainage12,13 and the risk of pancreatic fistula, which may ultimately require surgical intervention. In a review of published reports of percutaneous approaches with continuous catheter drainage, recur-

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rence ranged from 0% to 22%, with failure of drainage approaching 33% in some studies.11

Endoscopic Drainage There are two basic endoscopic approaches to the drainage of pseudocysts: trans-mural and trans-papillary. Trans-mural drainage involves the placement of one or more large bore stents through the gastric or duodenal wall into the cyst. This has been performed with and without endoscopic ultrasound (US) assistance. In one of the largest series of trans-mural drainage (34 patients), Beckingham and coworkers were able to demonstrate a 71% success rate with a 7% recurrence rate.14 Similar results have been found in more recent publications.15 Limitations of this procedure include thick-walled cysts (⬎1 cm) and those not in close proximity to the duodenum or stomach. Complications such as bleeding, infection of the pseudocyst, and perforation have occurred, although no associated mortality has been reported.14 Trans-papillary drainage is used primarily for pseudocysts that communicate with the pancreatic ductal system. This technique allows drainage of the collection directly into the ductal system, can address an obstruction of the pancreatic duct, and avoids some of the complications of trans-mural drainage. The only caveat to endoscopic therapy is the inability to perform adequate debridement and cyst wall biopsy. If there is any concern that a cystic neoplasm is present, surgical therapy in the form of laparoscopy or open exploration should be performed.

Laparoscopic Drainage There are many reports of laparoscopic management of pancreatic pseudocysts. Unfortunately, the majority of these involve very few cases. While case reports underscore the feasibility of the laparoscopic approach, they do not allow for determination of the success rate or the potential recurrence rate. Parks and Henniford reported one of the largest series, utilizing a variety of approaches.16 Twenty-nine cases were attempted by several techniques, including lesser sac cyst-gastrostomy,9 minilaparoscopic cystgastrostomy,5 transperitoneal intragastric cystgastrostomy,11 Roux en Y cyst jejunostomy,3 and external drainage.1 The procedure was completed in 28 of 29 cases; in one case it was aborted because of gastric varices. Unfortunately no long-term follow-up was available. In other case reports of successful laparoscopic management of pancreatic pseudocysts, patients remain asymptomatic with follow-up ranging from 2 to 12 months.17-21 The strength of the laparoscopic approach is the versatility in both the technique of drainage, as well as the potential to drain pseudocysts at various locations.

The laparoscopic approach, in contrast to other techniques, also allows a confident biopsy of the pseudocyst wall. Although less investigated than other minimally invasive techniques, the advantages of laparoscopy still hold promise for further application.

TECHNIQUE OF LAPAROSCOPIC PSEUDOCYST-GASTROSTOMY Our procedure of choice for draining pancreatic pseudocysts is pseudocyst-gastrostomy. Laparoscopic management of pancreatic pseudocysts typically involves the following steps: 1. Localization of the pseudocyst 2. Anterior wall gastrotomy 3. Biopsy of the pseudocyst wall to rule out a cystic pancreatic neoplasm 4. Creation of an anastomosis between pseudocyst and gastrointestinal tract of sufficient length to allow for drainage (ie, approximately 60 mm) 5. Verification of hemostasis 6. Gastrotomy closure Following the establishment of pneumoperitoneum and confirmation of safe entry into the peritoneal cavity, we proceed with a three-trocar technique. Additional trocars can be liberally added as necessary. We place one 5 to 12 mm trocar in the left upper quadrant subcostally, and one 5 mm trocar in the left upper quadrant just above the level of the umbilicus. The surgeon is located to the patient’s left side. The camera operator is located to the patient’s right side. The operation proceeds by incising the anterior wall of the stomach with an ultrasonic dissector to create a large access gastrotomy. Next, the surgeon must determine the precise area where the pseudocyst abuts the posterior wall of the stomach. This can usually be accomplished by visual inspection and palpation. If there is any question as to the location of the pseudocyst, ultrasound can be utilized to identify the lesion. An alternative technique for performing a pseudocyst gastrostomy involves entering the lesser sac via the gastrocolic ligament. Additional trocars including one in the right upper quadrant may be required. Once the lesser sac is entered and the gastrocolic ligament is opened widely, the stomach is retracted cephalad and the pseudocyst is identified using the above-mentioned techniques of aspiration with a needle or intra operative ultrasound. An ultrasonic dissector is used to create an access gastrotomy and pseudocystotomy. A side-to-side pseudocyst-gastrostomy can be performed with an endoscopic 2.5 mm linear stapler. The access pseudocyst-gastrotomy must then be closed with suture.

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2

The first step in the laparoscopic management of pancreatic pseudocysts is obtaining access to the peritoneal cavity and establishing pneumoperitoneum. We prefer to accomplish this using an open cut-down technique to place a blunt Hasson trocar at the umbilicus under direct vision. In patients who have undergone prior abdominal procedures and in whom we suspect dense adhesions in the midline, we use a blind Veress needle technique in the left upper quadrant to establish pneumoperitoneum. We then place a 5 mm trocar followed by a 5 mm 30° laparoscope in either of these locations. We have found this to be a safe way to access the abdominal cavity in patients with significant midline adhesions.

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Following anterior wall gastrotomy, the pseudocyst is aspirated to further confirm its location. The surgeon may use either a spinal needle or a Veress needle percutaneously passed through the posterior wall of the stomach.

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Once the location of pseudocyst adherence is determined, an ultrasonic dissector or cautery is used to develop a communication between the posterior gastric wall and the pseudocyst. A suction irrigation apparatus must be readily available to avoid wide spillage of the pseudocyst contents and contamination of the peritoneal cavity. It is critical at this point to send a biopsy from the pseudocyst wall to rule out the presence of epithelial cells. If these are present, the diagnosis is a cystic neoplasm of the pancreas and a pancreatic resection is indicated.

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The pseudocyst-gastrostomy is elongated. This can be accomplished with the use of a 60 mm endoscopic linear stapling device with 2.5 mm staples. For thicker walled pseudocysts 3.5 mm or larger staples must be used. The anastomosis must be closely examined for hemostasis. If any hemorrhage occurs, it should be controlled with interrupted figure of eight sutures. The surgeon must be prepared to complete the whole anastomosis by intracorporeal suturing if the psuedocyst is not suitable for stapling. Alternatively, the pseudocyst-gastrostomy may be created using an ultrasonic dissector, followed by marsupialization of the margin with a running nonabsorbable suture.

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Once hemostasis is verified, the anterior wall of the stomach is closed. This can be accomplished with an endoscopic linear stapling device or continuous running suture, depending on surgeon preference.

TECHNIQUE OF LAPAROSCOPIC PSEUDOCYST-JEJUNOSTOMY

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Roux-en-Y pseudocyst-jejunostomy is a technique that is useful for pseudocysts that are not intimately adherent to the posterior wall of the stomach. Port positioning in part will be determined by the position of the pseudocyst. Port positioning can be liberal, but likely can be accomplished using a 5 to 12 mm right upper quadrant epigastric trocar, a 5 to 12 mm left upper quadrant subcostal trocar, a 5 mm left upper quadrant trocar just above the level of the umbilicus, and an umbilical camera port. The creation of a Roux limb of jejunum proceeds by using upward retraction on the transverse colon to identify the ligament of Treitz. This also exposes the pseudocyst through the transverse mesocolon. The jejunum is then followed downstream to a point that will reach the pseudocyst without undue tension. The small bowel is transected at this point with an endoscopic 2.5 mm linear stapler. One additional firing of an endoscopic 2.5 mm linear stapler is used to transect the mesentery of this segment of jejunum perpendicular to the long axis of the intestine to gain added mobility.

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After mesenteric diversion, the distal segment is followed downstream at least 40 cm, at which point a side-toside jejunojejunostomy is performed using an endoscopic 2.5 mm linear stapler.

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The Roux limb of jejunum that has been fashioned is delivered into the upper abdomen. An ultrasonic dissector is used to create a pseudocystotomy through the transverse mesocolon and a jejunotomy. An endoscopic 2.5 mm linear stapler is then used to create a side-to-side pseudocyst-jejunostomy. The access pseudocystotomy-jejunotomy is then closed using running or interrupted suture.

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CONCLUSION The spectrum of minimally invasive techniques that have developed over the last 20 years has gradually improved but also complicated the management of pancreatic pseudocysts. It remains to be seen which technique, if any, will surface as definitive therapy. The complex variability of pseudocysts in terms of location, maturity, setting, and pancreatic ductal anatomy, will most likely perpetuate many of the current modalities for certain subsets of patients. This is certainly true for laparoscopic intervention, which as a minimally invasive technique is still maturing but has the versatility to remain an important part of the evolving treatment algorithm for pancreatic pseudocysts.

REFERENCES 1. Bradley EL: A clinically based classification system for acute pancreatitis. Arch Surg 128:586-590, 1993 2. Salvo AF, Nematolahi H: Distant dissection of a pancreatic pseudocyst into the right groin. Am J Surg 126:430-432, 1973 3. Yeo LJ, Sarr MG: Cystic and pseudocystic diseases of the pancreas. Curr Probl Surg 31:167-243, 1994 4. Castillo CF, Targarona J, Thayer SP, et al: Incidental pancreatic cysts: Clinicopathologic characteristics and comparison with symptomatic patients. Arch Surg 138:427-434, 2003 5. Bradley EL, Clements JL, Gonzalez AC: The natural history of pancreatic pseudocysts: A unified concept of management. Am J Surg 137:135-141, 1979 6. Pitchumoni SC, Agarwal N: Pancreatic pseudocysts: When and how should drainage be performed. Gastro Clin North Am 28: 615-635, 1999 7. Yeo CJ, Bastides JA, Lynch-Nyhan A, et al: The natural history of pancreatic pseudocysts documented by computed tomography. Surg Gynecol Obstet 170:411-417, 1990

8. Vitas GJ, Sarr MG: Selected management of pancreatic pseudocysts: Operative versus expectant management. Surgery 111:123130, 1992 9. Warshaw AL, Rattner DW: Timing of surgical drainage for pancreatic pseudocyst. Clinical and chemical criteria. Ann Surg 202: 720-724, 1985 10. Adams DB, Harvey TS, Anderson MC: Percutaneous catheter drainage of infected pancreatic and peripancreatic fluid collections. Arch Surg 125:1554-1557, 1990 11. Gumaste VV, Pitchumoni CS: Pancreatic pseudocyst. Gastroenterologist 4:33-43, 1996 12. Heider R, Meyer AA, Galanko JA, et al: Percutaneous drainage of pancreatic pseudocysts is associated with a higher failure rate than surgical treatment in unselected patients. Ann Surg 229:781-791, 1999 13. VanSonnenberg E, Wittich GR, Casola G, et al: Percutaneous drainage of infected and non-infected pancreatic pseudocysts: Experience in 101 cases. Radiology 170:757-761, 1989 14. Beckingham IJ, Krige EJ, Bornman PC, et al: Long term outcome of endoscopic drainage of pancreatic pseudocysts. Am J Gastroenterol 94:71-74, 1999 15. Vitale GC, Lawhon JC, Larson GM, et al: Endoscopic drainage of pancreatic pseudocyst. Surgery 126:616-621, 1999 16. Park AE, Henniford BT: Therapeutic laparoscopy of the pancreas. Ann Surg 236:149-158, 2002 17. Fowler DL, White SA: Laparoscopic cystogastrostomy. Surg Endosc 9:626, 1995 18. Gagner M: Laparoscopic transgastric cystgastrostomy for pancreatic pseudocyst. Surg Endosc 8:239, 1994 19. Ibrahim IM: Laparoscopic cyst-gastrostomy. Surg Endosc 8:975, 1994 20. Morino M, Garrone C, Locatelli L, et al: Laparoscopic management of benign pancreatic cystic lesions. Surg Endosc 9:625, 1995 21. Mouiel J, Crave F: Pancreatic cyst treated by laparoscopic cystojejunal anastomosis on a Roux-en-Y loop. Surg Endosc 9:625, 1995