The Pancreas > Pancreatic Surgery
DRAINAGE PROCEDURES FOR CHRONIC PANCREATITIS
BYPASS OPERATIONS FOR UNRESECTABLE NEOPLASMS
RADIOFREQUENCY ABLATION OF PDAC
MINIMALLY INVASIVE PANCREATIC SURGERY
A pancreatic resection is an operation to remove part of the pancreas. It is mostly performed to treat pancreatic neoplasms or in selected patients with chronic pancreatitis. Removal of the entire pancreatic gland is uncommon, but may be necessary in some cases. Here are outlined the key steps of pancreatic resections. Click on the following links to obtain more information.
Panctreaticoduodenectomy (PD) is most commonly performed for pancreatic head and periampullary malignancy, but may also be indicated in select cases of chronic pancreatitis or benign periampullary tumors. It is a major operation that involves the removal of the head of the pancreas, the duodenum, the gallbladder and the common bile duct (Figure 1). A short length of small intestine beyond the duodenum is also removed. In the classic Kausch-Whipple operation, the pylorus (outlet of the stomach) and the distal (lower) part of the stomach are removed, while in the Longmire-Traverso operation (pylorus-preserving pancreaticoduodenectomy), the stomach and the pylorus are not removed.
After resection, the end of the remaining bile duct; the remaining pancreas and the stomach are then connected to the small bowel to ensure flow of bile, digestive juices and food into the intestines (Figure 2). Three anastomoses are constructed:
- Pancreatic anastomosis. The pancreatic remnant is anastomosed to the jejunum (pancreatico-jejunostomy) or to the posterior wall of the stomach (pancreatico-gastrostomy).
- Biliary anastomosis. Hepatico-jejunostomy is performed between common hepatic duct remnant and a site on the jejunum distal to the pancreaticojejunal anastomosis.
- Enteric anastomosis. In Whipple PD, an antecolic anastomosis is constructed between the stomach and the jejunum; in Longmire-Traverso PD, an antecolic duodeno-jejunal anastomosis is created.
Different technical modifications of reconstruction techniques have been proposed, but none resulted superior in meta-analyses. The choice of the reconstruction technique to adopt depends on the surgeon’s preference and institutional practices.
Figure 1. Whipple pancreaticoduodenectomy
Left (or distal) pancreatectomy is performed to treat pancreatic diseases of the tail and body. This operation involves surgical resection of the body and tail of the pancreas to the left of the superior mesenteric-portal vein confluence. Left pancreatectomy can be carried out with or without associated splenectomy. The choice of procedure depends upon the disease process, and the characteristics of the lesion.
- Left pancreatectomy with splenectomy: The spleen, which is located near this part of the pancreas and shares some of the same blood vessels, needs to be removed as part of the procedure when the underlying pancreatic neoplasm is aggressive. Left pancreatectomy with splenectomy enables ligation of splenic vessels at their origin and an adequate lymph node clearance (Figure).
- Spleen-preserving left pancreatectomy: This procedure is reserved for benign/borderline pancreatic lesions and cysts, and for localized neuroendocrine tumors. There are two distinct approaches to preserve the spleen during the dissection of the distal pancreas. The classic design is to identify, isolate, and preserve the splenic artery and vein (Kimura procedure). Alternatively, the splenic artery and vein are ligated with the pancreas, and perfusion of the spleen is assured by the short gastric vessels (Warshaw procedure). Both are accepted as appropriate techniques to address a mass in the tail of the pancreas.
The pancreatic stump can be either hand-sutured, closed with a stapler, or sealed with harmonic scalpel. These stump closure techniques seem to be equivalent.
Minimally invasive surgery is becoming the paradigm in left pancreatic resections (laparoscopic and robot-assisted left pancreatectomy). In the next future, the number of left pancreatic resection performed with minimally invasive techniques is likely to increase due to a variety of factors including increased operator experience across centres and acceptance of the technique on the basis of demonstrated outcomes in premalignant and malignant lesions.
Figure. Left pancreatectomy with splenectomy
Total pancreatectomy involves the resection of the whole pancreas, the common bile duct, the gallbladder, the duodenum, a short segment of small intestine beyond the duodenum, the pylorus (outlet of the stomach), the distal (lower) part of the stomach, the spleen, and regional lymph nodes (Figure 1A).
After resection, the end of the remaining bile duct and the stomach are connected to the small bowel to ensure flow of bile and food into the intestines (Figure 2). Two anastomoses are constructed (Figure 1B):
- Biliary anastomosis. Hepatico-jejunostomy is performed between common hepatic duct remnant and a site on the jejunum.
- Enteric anastomosis. An antecolic anastomosis is constructed between the stomach and the jejunum; distal to the hepatico-jejunostomy.
Indications to single-stage elective total pancreatectomy include the presence of a multifocal neoplasm (intraductal papillary mucinous neoplasia, pancreatic metastases from clear cell renal carcinoma, neuroendocrine tumor in the setting of MEN1), or the presence of an intraductal papillary mucinous neoplasm involving the entire main pancreatic duct. Single-stage unplanned total pancreatectomy may be necessary after an initial partial pancreatectomy because of positive resection margins on intraoperative frozen section. Two-stage total pancreatectomy (completion pancreatectomy) is performed because of severe postoperative complications or neoplastic recurrence in the pancreatic remnant after previous pancreatic resection.
Total pancreatectomy is invariably associated with the development of exocrine insufficiency (inability to properly digest food) and endocrine insufficiency (diabetes mellitus). Management of pancreatic insufficiency include pancreatic enzyme replacement therapy and insulin therapy. Exocrine insufficiency and diabetes may be particularly hard to control in the first months after the operation, but studies have indicated that quality of life in the long term is satisfactory.
Figure 1. A: resection phase; B: reconstruction
Middle segment pancreatectomy consists of a limited resection of the midportion of the pancreas. This procedure allows a surgeon to preserve pancreatic parenchyma and consequently long-term endocrine and exocrine pancreatic function. Indications to middle segment pancreatectomy include benign and borderline neoplasms of the pancreatic body.
After identification and isolation of major vascular structures around the pancreatic body and neck, the segment of the pancreas with the tumor is transected to the left and to the right of the lesion (Figure 1A). The cephalic stump is sutured with interrupted stitches after elective ligation of the Wirsung’s duct or by means of a stapler.
The reconstruction phase involves one or two anastomoses:
- Pancreatic anastomosis. The pancreatic distal remnant is anastomosed to a jejunal Roux-en-Y loop (pancreatico-jejunostomy, Figure 1B) or to the posterior wall of the stomach (pancreatico-gastrostomy).
- Enteric anastomosis. After pancreatic-jejunostomy, the Roux loop is connected to the distal jejunum.
Figure 1. A: Middle pancreatectomy; B: reconstruction by pancreatic-jejunostomy on the distal stump
ENUCLEATION OF PANCREATIC NEOPLASMS
A pancreatic enucleation procedure is an operation designed to remove small (<2 cm), benign tumors of the pancreas. This procedure involves shelling out the tumor from the surrounding pancreas. For enucleation to be performed safely, the lesion should be at least 2-3 mm distant from the main pancreatic duct and not too deep in the parenchyma. If the lesion is too close to a duct, the risk of inadvertent ductal damage is substantial, and may result in a particularly hard to treat pancreatic fistula. Therefore, the distance between the tumor and the main pancreatic duct should be assessed preoperatively by means of magnetic resonance imaging with cholangio-pancreatography. Intra-operative ultrasound should be also performed to confirm the relationship between the neoplasm and the main pancreatic. Moreover, it allows clear identification of the lesion, and evaluation of its morphology and site.
The incidence of postoperative complications, particularly pancreatic fistula, is high, despite the majority of fistulas have an indolent course. The main advantage of enucleation is the preservation of almost all the pancreatic parenchyma, thereby minimizing the risk of long-term exocrine and endocrine insufficiency.
Enucleation can be performed using a minimally invasive approach.
Necrosectomy procedures are performed in patients with severe acute pancreatitis and infected necrosis. To date, necrosectomy is used a last resort, after failure of less invasive techniques (such as percutaneous drainage of pancreatic necrosis). This “step-up” approach has proven to be superior to the “step-down” approach in which open necrosectomy plays a primary role, with less invasive methods used for residual or subsequent collections.
The principle of necrosectomy is minimization of injury to viable tissues and maximization of postoperative removal of exudative fluid and extravasated pancreatic exocrine secretions from the operative bed. It may be a very difficult procedure, associated with an increased risk of bleeding.
Open necrosectomy is traditionally performed via a midline or a subcostal laparotomy. Once the focus of necrosis is exposed, debridement is carried out bluntly. After all loose debris has been removed, the retroperitoneal cavity is irrigated with normal saline solution. After necrosectomy, four different techniques are used to provide exit channels for further slough and infected debris:
- Open packing (The abdomen is left open, continuous reoperations with open lavage of necrotic areas are performed)
- Planned staged relaparotomies with repeated lavage (The abdomen is closed, continuous relaparotomies with open lavage of necrotic areas are performed)
- Closed continuous lavage of the lesser sac and retroperitoneum (the abdomen is closed over drains for contained postoperative lavage of the lesser sac and involved retroperitoneum)
- Closed packing (the abdomen is closed, reabsorbable sponges are used for packing)
Prof. Perderzoli and Prof. Bassi from Verona were among the first to describe in 1990 the procedure of open necrosectomy with continuous lavage of the lesser sac and retroperitoneum (Figure 1).
Figure 1. Open necrosectomy and continuous lavage of the lesser sac and retroperitoneum, as described by Pederzoli and Bassi in 1990.
MINIMALLY INVASIVE NECROSECTOMY
Minimally invasive necrosectomy encompasses radiological, endoscopic and percutaneous techniques. Minimally invasive necrosectomy techniques had been initially proposed as an alternative to open necrosectomy, with the aim of reducing the surgical trauma. However, a number of studies showed that open necrosectomy often makes patients sicker and that outcome may be improved when necrosectomy is delayed or when it is used a last resort, after failure of minimally invasive techniques.
However, these results may be influenced by variation in expertise with minimally invasive techniques, and in the definitions of target lesions. Variations in the target lesions (location of necrosis, fluid/mixed/solid nature, early/late procedure, sterile/infected necrosis, single/multiple areas, wall thickness) and in the patients (co-morbidity, degree of organ dysfunction) require an individually tailored approach to the treatment of pancreatic necrosis.
As reported by Windsor, minimally invasive techniques can be classified by the type of scope used (flexible endoscope, laparoscope, nephroscope) and the route of access (transperitoneal, transgastric, retroperitoneal).
The two approaches that have risen to favour are the endoscopic transgastric and nephroscopic retroperitoneal routes.
Endoscopic transgastric necrosectomy involves include endoluminal ultrasonographically guided transgastric puncture of the necrotic area, balloon dilatation of the track, insertion of multiple stents, direct basket extraction of necrosum, and transpapillary stenting of the pancreatic duct. The endoscopic transgastric procedure avoids peritoneal contamination and external pancreatic fistula formation, but it may not be possible if there is no abutment of the lesion against the stomach or duodenal wall.
The nephroscopic retroperitoneal procedure has been advocated by the Glasgow group and appears now to be the most popular minimally invasive necrosectomy approach. The various techniques described may use a small retroperitoneal incision or rely on dilatation of a drain-track. The majority utilize contrast-computed tomography (CT) or image itensifier to guide the placement of small-calibre percutaneous drains into retroperitoneal collections. The drain-track is then dilated using the Seldinger technique and a nephroscope is placed into the cavity and semi-solid necrotic tissue removed piecemeal. This is achieved using various accessories, including biopsy forceps and baskets.
DRAINAGE PROCEDURES FOR CHRONIC PANCREATITIS
Drainage procedures (anastomoses between the pancreas or a pseudocyst and a segment of intestine) are performed to relieve intra-pancreatic and ductal pressure, re-establish an adequate pancreatic juice outflow, and resolve pain. Internal drainage may be necessary to resolve symptoms caused by a large or infected pseudocyst.
A dominant component of chronic pancreatitis is the pancreatic duct hypertension, caused by fibrotic replacement of normal pancreatic tissue. Duct stenosis and hypertension are the basis of the duct pressure-pain hypothesis. Drainage operations are performed on the assumption that pain relief is obtained by drainage of the main pancreatic duct.
Longitudinal decompression of the main pancreatic duct (at the level of the body-tail) was proposed in the ’50s by Puestow and modified in 1960 by Partington and Rochelle (latero-lateral Wirsung-jejunostomy) became the first surgical treatment widely considered to be effective for pain in chronic pancreatitis. Briefly, after accessing the lesser sac, a ventral incision of the main pancreatic duct is made until the head of the pancreas, at the level of gastroduodenal artery. The Wirsung duct is then anastomosed with a Roux-en-Y loop. Only patients with dilated pancreatic duct are amenable of lateral pancreatico-jejunostomy. According to the current literature, the immediate success rate is about 80%, but 30% experience pain recurrence after 3-5 years, probably because of concomitant inflammatory mass in the head of the pancreas.
Izbicki et al. proposed a technical modification (pancreatic longitudinal excavation and lateral pancreatico-jejunostomy) to treat patients with small, non-dilated main pancreatic duct (< 5 mm).
In the early 1970s, it was observed that many patients with chronic pancreatitis had an inflammatory mass in the head of the pancreas. The three principal ductal systems (Wirsung duct, Santorini duct, and uncinate process duct) adjoin in the head of pancreas, that may represent the “core”in which the disease begins. Therefore, hybrid approaches that associate partial pancreatic head resection with drainage of the main pancreatic duct were proposed.
In 1972 Beger introduced the duodenum-preserving pancreatic head resection. By subtotal resection of the pancreatic head and by preserving the body and tail of the pancreas, pylorus, duodenum, and extra-pancreatic bile ducts, this operation preserves the normal anatomy of the upper gut and the normal passage of food. The intention of this operation is to treat only the enlarged pancreatic head. Reconstruction involves an end-to-side pancreaticojejunostomy and a side-to-side pancreaticojejunostomy. If necessary, the body and the tail can be drained via a longitudinal pancreaticojejunostomy. Immediate relieve of pain has been reported in 80% of patients.
Combining the surgical principles of drainage and organ-preserving resection, Frey introduced in 1987 a modification of the duodenum-preserving pancreatic head resection, the longitudinal pancreatojejunostomy with local pancreatic head resection. Key steps in the performance of the Frey procedure include preservation of the pancreatic neck as well as the capsule of the posterior pancreatic head. The ducts of Wirsung and Santorini are excised, and the excavation is created in continuity with the longitudinal dochotomy of the dorsal duct. The locally excised head of the pancreas is covered with the opened Roux-en-Y limb of jejunum in continuity with the opened main pancreatic duct in the body and tail of the pancreas. Results are similar to those of the Beger procedure.
INTERNAL DRAINAGE OF PSEUDOCYSTS
Drainage of pancreatic pseudocysts can be performed either percutaneously, endoscopically or surgically.
Percutaneous drainage of pseudocyst is the least employed technique. Endoscopic drainage is the treatment of choice if there is abutment of the pseudocyst against the stomach or duodenal wall. The procedure involves endoluminal ultrasonographically guided transgastric puncture of the pseudocyst, insertion of single or multiple stents, and – if necessary – transpapillary stenting of the pancreatic duct.
Surgical drainage is indicated when endoscopic drainage is not feasible (there is no abutment of the pseudocyst against the stomach or duodenum, there is extensive collateral circle) or after multiple endoscopic drainage failure.
The surgical approach involves a pseudocystogastrostomy on the posterior stomach wall (that can be fashioned via an anterior gastrotomy), or a pseudocystojejunostomy on a Roux-en-Y loop. The pseudocyst wall should be thick and solid enough to allow the fashioning of the anastomosis.
BYPASS OPERATIONS FOR CANCER
Bypass operations are considered if the pancreatic tumor is unresectable. These are palliative procedures that are mostly required in pancreatic head neoplasms, and that are intended to relieve or prevent symptoms, the most common being:
- Jaundice: it is the yellowing of the eyes and skin caused by the buildup of bilirubin in the body. When the portion of common bile passing within the pancreatic head becomes compressed or infiltrated by the tumor, bile can’t reach the intestines, and the level of bilirubin builds up
- Duodenal obstruction: the neoplasm may infiltrate the far end of the stomach or the duodenum, partly blocking them. This can cause nausea, vomiting, and pain that tend to be worse after a meal
Bypass procedures may be proposed if other less invasive palliative treatments (endoscopic stent placement) failed and the symptoms are worsening. Sometimes surgery may begin with the attempt to cure the patient (radical resection), but an unexpected locally advanced or a metastatic disease is found. In this case, the surgeon may continue the operation as a palliative procedure to relieve or prevent symptoms. Although recent advances of cross sectional imaging allow detailed evaluation of the pancreas, the accuracy of radiologic staging is not 100%, and the surgical exploration still plays the key role for the finally assessment of resectability.
Bypass operations can reroute the flow of bile from the common bile duct directly into the small intestine, bypassing the pancreas (hepatico-jejunostomy or choledoco-jejunostomy). The stomach connection to the duodenum can be rerouted at this time as well (gastro-jejunostomy). Figure 1 shows the double bypass procedure (hepatico-jejunostomy and gastro-jejunostomy).
RADIOFREQUENCY ABLATION OF ADVANCED PDAC
Radiofrequency ablation of pancreatic neoplasms
is an experimental technique that has been deveoped by a research consortium (Unit of Pancreatic Surgery at the Peschiera del Garda Hospital and Unit of Pancreatic Surgery in Verona). It is currently employed in patients with locally advanced ductal adenocarcinoma (PDAC).
Radiofrequency ablation (RFA) is a local ablative method that can destroy the tumour by thermal coagulation and protein denaturation. RFA has been used successfully in the treatment of unresectable solid tumours in the liver, lung, kidney, brain, breast, prostate, bone, adrenal glands and spleen. Application of RFA to the pancreas presents potential problems related to the properties of the pancreatic parenchyma (soft and friable) and to the risk of inadvertent thermal injury to the distal common bile duct, duodenum, transverse colon and portal vein.
Our group demonstrated in 2010 the feasibility and safety of pancreatic radiofrequency ablation in a group of 50 patients. Mortality was 2% and morbidity was 24%. Furhter technical refinements have been applied, such that mortality has decreased to 1%, and the severity profile of complications has substantially improved. To date, we have performed more than 200 procedures, and we are investigating the role of radiofrequency ablation in the context of a randomized clinical trial. Figure 1 shows the effects of radiofrequency ablation of a locally advanced pancreatic head ductal adenocarcinoma as seen on postoperative perfusion-CT scan.
Radiofrequency is a palliative procedure, the presence of residual viable tumor at the periphery of the treated area being an intrinsic aspect of the procedure. Survival data of patients treated in Verona, calculated from an observational non-randomized analysis, seem encouraging. Radiofrequency ablation seems to be a locally effective approach, and may be considered as part of a multimodal treatment for advanced pancreatic ductal adenocarcinoma. Current indications to radiofrequency include:
- Confirmed locally advanced pancreatic ductal adenocarcinoma (radiologic staging + biopsy)
- Age 18-80 years
- Stable or locally progressive disease after chemotherapy or chemoradiotherapy
- Performance status >50% (Karnofsky) or <=2 (ECOG)
Radiofrequency ablation is performed via a laparotomy. Accurate exploration of the peritoneal cavity is performed and supported by intraoperative ultrasonography in order to rule out previously undetected metastases and confirm unresectability of the lesion. The probe is placed in the centre of the lesion under ultrasonographic guidance, intraoperative ultrasonography is also used during the procedure to monitor the coagulative effect. When technically feasible, a biliary and gastric bypass is performed in patients with tumors of the pancreatic head. Gastric bypass is performed only if necessary in patients with tumors of the body-tail.
Raiofrequency ablation is a major surgical procedure to be carried our in centers with broad experience in pancreatic surgery. A careful multidisciplinary evaluation (surgeon, radiologist, oncologist) is necessary to design the best care plan for each patient.
Although in expert hands radiofrequency ablation is safe, post-operative morbidity (similarly to pancreatic resections) is substantial. Postoperative complications associated with radiofrequency ablation of pancreatic solid tumors include:
- Portal vein/superior mesenteric vein thrombosis
- Ischemic duodenal ulcers
- Thermal acute pancreatitis
- Pancreatic fistula and abdominal collections
CT-scans are performed after 7 and 30 days from the procedure to monitor the ablated area. The patients are referred to the Oncologist for possible prosectution of chemotherapy or chemo-radiotherapy, and are enrolled in a strict surveillance protocol, including a detailed clinical examination, measurement of serum Ca 19.9, and cross-sectional imaging.
Figure 1. Left: Preoperative CT-scan showing a locally advanced pancreatic head ductal adenocarcinoma. Right: Postoperative perfusion CT-scan showing the ablated area, devoid of blood supply.
MINIMALLY INVASIVE PANCREATIC SURGERY
Minimally invasive surgery is performed through small incisions, usually between 5-15 mm. The surgeon then inserts specially designed, thin instruments and sophisticated video equipment to perform the operation through the smaller opening. Depending on the procedure, minimally invasive surgery can be performed with the surgeon manipulating the instruments by hand (laparoscopic surgery) or with the surgeon directing robotic arms (robot-assisted surgery).
Minimally invasive surgery offers many benefits over traditional techniques, including less injury to tissue, less postoperative pain, shorter hospital stays, quicker return to normal activities, minimal scarring, less incisional hernias. Over the past 20 years minimally invasive surgery has evolved to such an extent that in suitably qualified hands the majority of general surgical procedures can be safely carried out.
The complexity of pancreatic surgery has meant that the development of laparoscopic techniques and particularly formal resections has been relatively slow compared with procedures in many other surgical specialties. Consequently its incorporation into regular clinical practice is recent, and initial indications were limited to benign and borderline neoplasms. Recent data indicate that laparoscopic pancreatic resections are oncologically adequate, and can be safely applied to malignant neoplasms. The most commonly performed laparoscopic pancreatic resections are left pancreatectomy and enucleation, whereas the experience with pancreaticoduodenectomy and middle pancreatectomy is limited.
Miimally invasive surgery has been further enhanced by the use of robotics. Robotic surgery is a technique in which a surgeon performs surgery using a computer that remotely controls very small instruments attached to a robot. With the surgeon sitting at a console a few metres from the patient, the robot translates that surgeon’s hand movements into corresponding micro-movements of instruments inside the patient’s body. The robotic system provides better visualization, dexterity, precision and control than open surgery, while enabling the surgeon to perform procedures through tiny, 1-2 cm incisions. The world experience on the use of robotic systems for surgery on the pancreas is growing, but remains limited.
The Unit of Pancreatic Surgery in Verona has one of the largest minimally invasive practice in Italy. Our program has a history of pioneering innovative, minimally invasive approaches such as left pancreatectomy with splenectomy, spleen-preserving left pancreatectomy, enucleation, middle pancreatectomy. We have developed experience with the da Vinci Si HD robotic system for left pancreatectomy, with or without splenectomy, and enucleation.
A robot-assisted pancreatic resection
The da Vinci Si HD robotic system.