Pancreatosplenectomy and Spleen-Preserving Distal Pancreatectomy Technique

Staging laparotomy should be performed before resection. The peritoneum, omentum, mesentery, and viscera should be visually inspected and palpated for signs of peritoneal or metastatic disease.

Once the abdomen is entered, the lesser omentum can be accessed by dividing the gastrocolic ligament below the gastroepiploic vessels. The short gastric vessels are ligated to expose the body and tail of the pancreas. ^[22] (See the image below.)

The spleen is mobilized by dividing the splenorenal and splenophrenic ligaments. The remaining short gastric vessels at the upper pole of the spleen should be divided.

The peritoneal reflection covering the pancreas is divided with Metzenbaum scissors or electrocautery. Sharp dissection behind the pancreas frees it from the retroperitoneal space, and care should be taken to remain in the plane between the kidneys and pancreas, leaving Gerota’s fascia intact. As the spleen is retracted medially with the tail of the pancreas, small perforating vessels are ligated and divided. This maneuver allows direct visualization of the posterior aspect of the pancreas. (See the image below.)

The splenic artery, located superiorly, should be clearly identified and ligated at its origin. The splenic artery should be ligated first to avoid splenic congestion. The confluence of the splenic vein and the superior mesenteric vein (SMV) posteriorly should be dissected, and the splenic vein should be ligated and divided at its junction with the SMV. (See the image below.)

The pancreas can then be divided with either the electrocautery or a gastrointestinal anastomosis (GIA) stapler. The pancreatic duct should be identified and suture-ligated with 3-0 polydioxanone or polypropylene sutures. A horizontal mattress, figure-eight, or continuous suture can all be used as methods to close the pancreatic remnant. A Jackson-Pratt drain is placed near the transected end of the pancreatic remnant and brought out through a separate incision. The abdomen is closed with a 1-0 polydioxanone suture and staples on the skin.

Radical antegrade modular pancreatosplenectomy (RAMPS) ^[23]  was described by Strasberg et al ^[24]  as an approach to distal pancreatectomy that allows better oncologic resection with lymphadenectomy. If there is extensive tumor involvement, this resection allows en-bloc removal of the pancreas and all involved tissue.

The lesser sac is entered as previously described for open retrograde distal pancreatosplenectomy, and the dissection is carried to the origin of the right gastroepiploic artery.

From the inferior border, the pancreatic neck is dissected off of the SMV and the portal vein. ^[1]  The middle colic vein may be ligated if necessary to facilitate exposure. The common hepatic artery should be identified at the superior border of the pancreas. The common hepatic artery is traced distally to identify the lymph nodes on the hepatic artery proper and the portal vein, which are mobilized in the hepatoduodenal ligament. Ligating the gastroduodenal artery reveals the anterior surface of the portal vein and allows its complete dissection away from the pancreatic neck.

The neck is then transected with either a GIA stapler or an electrocautery. The splenic artery and vein are then ligated and divided at their respective origins.

Depending on the extent of tumor involvement, dissection is extended posteriorly to include retroperitoneal tissue and lymphatics anterior to the left renal vein and adrenal gland. Careful vertical dissection should reveal the origin of the superior mesenteric artery (SMA) from the aorta, which should fall within the boundaries of the lymphadenectomy. Lymph nodes should be taken in the area to the left of the SMA, bounded superiorly and inferiorly by the celiac axis and SMA and posteriorly by the aorta.

The spleen is mobilized by dividing the splenorenal and splenophrenic attachments. An R0 resection may require en-bloc removal of the left adrenal gland and kidney, the transverse colon, the stomach, the duodenum, and the jejunum. ^[6]

A drain is left adjacent to the pancreatic bed.

Robot-assisted RAMPS has been described as well. ^[25]

The approach for spleen-preserving distal pancreatectomy is similar to that described for RAMPS. Despite the increase in time due to the difficulty with dissection, preserving the spleen has the additional benefit of preserving hematologic and immunologic function. It has been shown to be safe when compared to distal pancreatosplenectomy. ^{[26, 27]}

The lesser sac is entered as previously described for open retrograde distal pancreatosplenectomy, and the dissection is carried to the origin of the right gastroepiploic artery.

From the inferior border, the pancreatic neck is dissected off of the SMV and the portal vein. ^[1]  The middle colic vein may be ligated if necessary to facilitate exposure. The common hepatic artery should be identified at the superior border of the pancreas. The common hepatic artery is traced to identify the lymph nodes on the hepatic artery proper and portal vein, which are mobilized in the hepatoduodenal ligament. Ligating the gastroduodenal artery reveals the anterior surface of the portal vein and allows its complete dissection away from the pancreatic neck.

The splenic artery and vein are carefully dissected from the posterior surface of the pancreas. Vascular control with vessel loops or a Penrose drain can be used for retraction or in the event of vascular injury and hemorrhage. The pancreas is then divided and rotated laterally. As the pancreas is gently elevated, short branches of the splenic artery and vein entering the pancreas are ligated with surgical ties or clips and then cut.

The dissection is carried out from medial to lateral in the direction of the splenic hilum. Once all pancreatic branches to the splenic vein have been ligated and divided, the pancreatic body and tail are removed.

The pancreatic stump is then treated according to the surgeon's preference, and a drain is left near the pancreatic remnant.

Questions have been raised regarding whether it is preferable to preserve or ligate the splenic vessels in a spleen-preserving distal pancreatectomy. Some analyses have suggested that splenic vessel preservation is associated with lower complication rates ^{[28, 29]} ; however, the available data are limited, and further studies are warranted.

The patient should be placed supine or in a modified lithotomy position with the left side elevated.

The first trocar should be a 10-mm supraumbilical port just to the left of the midline. The abdomen is insufflated, and subsequent trocars are placed under direct visualization by using a 10-mm 30º laparoscope. A staging laparoscopy is performed by inspecting peritoneal surfaces, the omentum, mesentery, and all viscera. ^[24]

A second 10- to 12-mm trocar is placed in the left midclavicular line. A 5-mm trocar is then placed in the midepigastric/subxiphoid area. The fourth trocar is placed in the left anterior axillary line. ^[30]

The lesser omentum is entered by dividing the transverse mesocolon toward the spleen. As the stomach is retracted cephalad, attachments to the pancreas should be divided. The dissection is continued medially along the inferior aspect of the gastroepiploic vessels.

The spleen is mobilized by dividing the splenocolic ligament. The short gastric vessels are ligated and divided with an ultrasonic scalpel, a coagulator, or clips.

The pancreas should be dissected at the superior border to identify the splenic artery. At this point, if dissection is adequate, the splenic artery can be ligated and divided. The splenic artery and vein are dissected away from the posterior border to allow retraction of the pancreas.

An endoscopic GIA stapler is used to divide the pancreas. If this was not previously done, the splenic artery is identified and transected by using a vascular load. As the pancreas is retracted laterally, the splenic vein is divided in a similar manner. The pancreas can also be transected as a unit with the artery and vein. ^[30]  The remaining splenic attachments are divided to facilitate removal. The midline incision is extended, and the specimen is removed in an endoscopic retrieval pouch.

If the spleen is to be preserved, the splenic vessels may be either ligated or preserved. A study by Worhunsky et al did not find either approach to be clearly superior with regard to outcome and splenic preservation and concluded that the choice should be based on technical considerations, including the location of the tumor in the pancreas. ^[31]

A dual-incision approach to laparoscopic spleen-preserving distal pancreatectomy has been described that uses fewer trocars. Kim et al assessed the safety and feasibility of this approach (n = 22) versus conventional laparoscopic spleen-preserving distal pancreatectomy (n = 26) and reported significantly shorter operating times and reduced blood loss in the dual-incision group, as well as more successful preservation of splenic vessels. ^[32]

Robot-assisted approaches to pancreatoduodenectomy and distal pancreatectomy have been described that appear comparable to conventional laparoscopic approaches in terms of perioperative outcomes; however, there is a need for further randomized controlled trials to achieve a clearer determination of the clinical safety and efficacy of these approaches. ^{[33, 34]}

Guidelines addressing laparoscopic and robotic distal pancreatectomy have been developed by the International Study Group on Minimally Invasive Pancreas Surgery (I-MIPS). ^[12]

Various techniques have been described for resection of the pancreas and treatment of the pancreatic remnant. These techniques have included pancreatic duct ligation, sealing with fibrin glue or prolamine injection in the pancreatic duct, transection with an ultrasonic coagulator, transection with linear stapling devices, gastric or jejunal seromuscular patch, use of a vascularized omental flap, enteric drainage, and pancreaticojejunal anastomosis. ^[35]

These methods have all been attempted in an effort to decrease the risk of postoperative pancreatic duct leak and fistula formation. Studies have not established any one method as clearly superior. However, the most commonly used methods are linear staple transection and pancreatic transection with ligation of the pancreatic duct and closure of the remaining stump.

Risk factors associated with increased mortality include the following ^[36] :

• Male sex
• Obesity
• Smoking
• Steroid use
• Neurologic disease
• Hypoalbuminemia
• Abnormal platelet count
• Elevated creatinine

Complications include hemorrhage, pancreatic leak, pancreatic fistula (2-24%), intra-abdominal abscess (1-12%), new-onset insulin-dependent diabetes, pancreatic enzyme insufficicency (PEI) and steatorrhea, small-bowel obstruction, sepsis, and surgical-site infection (SSI). ^{[6, 37]}

The American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) found sepsis to be the most common complication (8.7%), followed by SSI (5.9%) and pneumonia. In a multivariate analysis of distal pancreatectomy by Kelly et al, ^[37]  the 30-day complication rate was 28.1%, serious complications occurred in 22.2% of cases, and mortality was 1.2%.

Risk factors for pancreatic fistula include the following ^[38] :

• Malnutrition
• Jaundice
• Soft pancreatic remnant
• Cirrhosis
• Coronary artery disease with absence of arterial hypertension
• Renal failure
• Emergency surgery
• Reoperation

Methods for decreasing pancreatic leaks and fistulas have been investigated (eg, fibrin glue on the transected pancreas, somatostatin, and octreotide), but no method has been established as clearly superior. However, a Cochrane review demonstrated an overall 34% decreased incidence of pancreatic leak with the use of somatostatin analogues. This best-evidence paper recommended the use of somatostatin analogues in the postoperative period for patients undergoing pancreatic resection. ^[39]

The literature has suggested that using a stapler to transect the pancreas can decrease pancreatic leak and fistula rates, but more investigations are needed before a definitive conclusion can be drawn. Drain placement is recommended to help identify and control pancreatic leaks. ^[40]