Pancreatosplenectomy and Spleen-Preserving Distal Pancreatectomy

Pancreatosplenectomy (pancreaticosplenectomy) or spleen-preserving distal pancreatectomy is performed to surgically treat pancreatic disease of the tail and body. Distal pancreatectomy involves surgical resection of the body and tail of the pancreas to the left of the superior mesenteric vein (SMV)–portal vein confluence,[1]  with or without splenectomy.

The choice of procedure depends upon the disease process, the characteristics of the lesion, and the surgeon's experience. Spleen-preserving distal pancreatectomy is reserved for chronic pancreatitis, proven benign pancreatic lesions and cysts, neuroendocrine tumors, and trauma.

Lesions in the body and tail of the pancreas become symptomatic as they enlarge and invade surrounding structures. However, with the increasing use of imaging studies, more incidental pancreatic lesions are discovered and diagnosed. Smaller lesions diagnosed at earlier stages are more amenable to surgical treatment.

Pancreatic neoplasms

Adenocarcinomas of the distal pancreas account for 15-25% of pancreatic adenocarcinomas.[2] Distal pancreatosplenectomy with lymphadenectomy is indicated for adenocarcinoma that is locally resectable without distant metastasis. Spleen-preserving distal pancreatectomy is contraindicated for malignant lesions of the distal pancreas.

Neuroendocrine tumors represent 2-4% of pancreatic tumors.[2] All neuroendocrine tumors have malignant potential and should be resected with curative intent.

Solid pseudopapillary tumors are evenly distributed throughout the pancreas, with 46-67% present in the body and tail. These tumors represent 0.9-2.5% of solid pancreatic tumors, with 82-93% of cases diagnosed in young women.[2] Curative resection should be attempted unless other contraindications are present.

Chronic pancreatitis

Chronic pancreatitis is defined as chronic and recurrent inflammation of the pancreas.[3]  Surgery is indicated for pain, pseudocysts, suspicion of malignancy, stenosis of the middle to distal pancreatic duct, pancreatolithiasis, and stenosis of the celiac or mesenteric vessels. Intractable pain is the most common indication for distal pancreatectomy in chronic pancreatitis, with relief of symptoms in 31-90% patients.[3, 4]

Pancreatic cysts

Serous cystadenomas are typically benign and represent 20-40% of cystic pancreatic tumors; they do need resection unless a large tumor is causing obstructive symptoms.[5] Mucinous tumors have malignant potential and account for 20-40% of cystic tumors.[5] Resection is indicated in symptomatic enlarging cysts larger than 2 cm. Intraductal papillary mucinous tumor is believed to follow the adenoma-carcinoma sequence and should be resected with curative intent.

Because of their similarities in appearance on diagnostic imaging, pancreatic pseudocysts and cystic tumors may be distinguished by means of endoscopic ultrasonography (EUS) with fine-needle aspiration (FNA). Findings suggestive of malignancy include mucin, mucin-secreting cells, or a high carcinoembryonic antigen (CEA) level in the cyst fluid.[5]

Symptomatic or enlarging pancreatic pseudocysts in the tail fo the pancreas can be treated with distal pancreatectomy after the acute pancreatitis episode has resolved. However, pseudocysts are best treated with internal drainage procedures as opposed to resection.

Contraindications for distal pancreatosplenectomy and spleen-preserving distal pancreatectomy include the following:

• Metastatic disease
• Peritoneal carcinosis
• Vascular invasion
• Pancreatitis involving the entire pancreas

Anatomy

The pancreas, from Greek pan- ("all") and kreas ("flesh"), is a 12- to 15-cm-long J-shaped (like a hockey stick), soft, lobulated, retroperitoneal organ. It lies transversely, though a bit obliquely, on the posterior abdominal wall behind the stomach, across the lumbar (L1-2) spine (see the image below).

The head of the pancreas lies in the duodenal C loop in front of the inferior vena cava (IVC) and the left renal vein. The body and tail of the pancreas run obliquely upward to the left in front of the aorta and left kidney. The pancreatic neck is the arbitrary junction between the head and body of the pancreas. The narrow tip of the tail of the pancreas reaches the splenic hilum in the splenorenal (lienorenal) ligament.

For more information about the relevant anatomy, see Pancreas Anatomy.

Procedural planning

About 50% of patients with adenocarcinoma have locally-advanced unresectable disease, and 35% have distant metastasis at the time of diagnosis.[6] Therefore, staging laparoscopy is recommended prior to resection. Major vasculature involvement with the celiac root, peritoneal disease, and metastasis to the liver are contraindications for resection.[6]

There has not been a clear consensus regarding whether a laparoscopic or an open distal pancreatectomy should be performed.[7, 8] Laparoscopic distal pancreatectomy has advantages similar to other laparoscopic procedures, such as decreased intraoperative blood loss, fewer postoperative complications and decreased length of stay.[9, 10] (See Outcomes.) However, the general view has been that its applicability in the setting of malignancy requires further study.[11]

In 2020, guidelines on minimally invasive pancreas resection were released by the International Study Group on Minimally Invasive Pancreas Surgery (I-MIPS).[12]  According to these guidelines, minimally invasive distal pancreatectomy (MIDP) for benign and low-grade malignant tumors is to be considered over open distal pancreatectomy (ODP). MIDP for pancreatic ductal adenocarcinoma appears to be feasible, safe, and oncologically equivalent in experienced hands. As of the publication of the I-MIPS guidelines, no studies had specifically compared spleen-preserving MIDP with spleen-preserving ODP.

Complication prevention

When a splenectomy is planned with a distal pancreatectomy, meningococcal, pneumococcal, and Haemophilus influenzae type B vaccines should be given, ideally 2 weeks prior to the planned resection. Antibiotics, such as a second- or third-generation cephalosporin, should be administered 30 minutes prior to incision.

Multiple meta-analyses have demonstrated laparoscopic distal pancreatectomy to be safe with improved postoperative outcomes as compared with open resection.[13]  Jin et al found laparoscopic distal pancreatectomy to be associated with fewer blood transfusions, decreased blood loss, earlier oral intake, and fewer surgical-site infections (SSIs).[14]  There was no difference found in operative time or incidence of pancreatic fistula.

In a retrospective review by Kooby et al,[9]  short-term oncologic outcomes (node harvest, margin status) and long-term oncologic outcomes (survival) were comparable in open and laparoscopic distal pancreatectomy.

A review article by Borja-Cacho et al[15]  concluded that laparoscopic distal pancreatectomy had a similar morbidity to open pancreatectomy but had a decreased length of stay. This study concluded that laparoscopic distal pancreatectomy is a safe procedure that is appropriately used for benign pancreatic disease. A randomized prospective multicenter trial would be required for further comparison to determine whether laparoscopic distal pancreatectomy is appropriate in malignant pancreatic lesions.

In a randomized trial by Nigri et al,[16]  the conversion rate for laparoscopic to hand-assisted technique was 37%. The conversion rate for laparoscopic to open was 11%. Reasons for conversion included multiple intra-abdominal adhesions and hemorrhage.

Several studies have examined the feasibility of robotic distal pancreatectomy. Robotic procedures have the benefits of three-dimensional (3D) visualization and improved ergonomics to allow for fine dissection. The safety profile is similar to that for laparoscopic procedures; however, robotic distal pancreatectomy has been associated with increased cost and operating times.

Because of the varying outcomes in negative margins and lymph node yield, there has been a lack of consensus regarding the oncologic appropriateness of robotic distal pancreatectomy in malignancy.[17, 18]  The 2020 I-MIPS guidelines stated that both laparoscopic distal pancreatectomy and robotic distal pancreatectomy are safe and feasible and suggested that the choice of technique should be based on surgeons’ experience and local resources.[12]

Murakawa et al evaluated short- and long-term outcomes in 49 consecutive patients who underwent radical antegrade modular pancreatosplenectomy (RAMPS; see Technique) for pancreatic cancer.[19]  They reported a median operating time of 278 minutes (range, 140-625), a median intraoperative blood loss of 850 mL (range, 60-2790), an overall morbidity of 51.4%, and a mortality of 0%. After follow-up (median, 41.1 mo), the overall survival rate was 84.1% at 1 year and 38.6% at 3 years. Median overall survival was 22.6 months.

Abe et al studied 93 patients who underwent treatment of pancreas body and tail adenocarcinoma, comparing the results of standard retrograde pancreatosplenectomy (SRPS; n = 40) with those of RAMPS (n = 53).[20] In the RAMPS group, more lymph nodes were retrieved (28.4 ± 11.6 vs 20.7 ± 10.1), R0 resection was more frequent (90.5% vs 67.5%), there was less intraoperative bleeding (485.4 ± 63.3 mL vs 682.3 ± 72.8 mL), and operating time was shorter (267.3 ± 11.5 min vs 339.4 ± 13.2 min). 

Huo et al, in a meta-analysis of seven studies (N = 474) comparing RAMPS with SRPS in patients with left-side pancreatic cancer, found that the RAMPS group had a better overall survival than the SRPS group.[21] Significantly more lymph nodes were harvested in the RAMPS group, and this group also showed reductions in blood loss and recurrence rate. More high-quality clinical trials would be required to confirm these findings.

Preoperative placement of invasive monitors, such as an arterial line and a central venous line, should be considered and used in accordance with the patient’s clinical picture.

A standard general surgery open tray can be used. A gastrointestinal anastomosis (GIA) stapler, surgical clips, an ultrasonic scalpel, and vascular clamps should also be available in the event of vascular injury.

Various techniques for transecting the pancreas are described (see Technique and Laparoscopic Pancreatectomy). The appropriate instruments for a given approach should be available, according to the surgeon's preference and experience.

This procedure is completed with the patient under general endotracheal anesthesia.

After anesthesia is induced, the patient is placed on the table in a supine position with the arms extended or in a modified right lateral decubitus position with the arms tucked. For the open approach, a midline, left subcostal, or bilateral subcostal incision allows adequate exposure. Trocar placement for laparoscopic distal pancreatectomy is discussed elsewhere (see Technique and Laparoscopic Pancreatectomy).

If stable, patients can be sent to a surgical floor in the immediate postoperative period. Unstable patients should be admitted to the intensive care unit (ICU) for further resuscitation and monitoring. A diet can be started as early as postoperative day 1 and advanced as tolerated to a diabetic diet.

Drain output should be recorded daily and monitored for increases in output and changes in color as the diet is advanced. A drain amylase level should be checked prior to discharge with a cutoff value of greater than 5000 U/L of amylase for removal or continuation. If a fistula is suspected and adequately drained, the drain should remain until the fistula resolves.

Pancreatic fistulas can form along the track of the previous drain, and should be managed conservatively. Fistula was defined by the International Study Group of Pancreatic Fistula as “output via an operatively placed drain of any measurable volume of drain fluid on or after postoperative day 3 with amylase content greater than three times the upper normal serum value.”[15]

The drain is removed once the output has decreased. Fistulas typically heal spontaneously, but output can be controlled with a low-fat diet and somatostatin analogues (eg, octreotide). Treatment of persistent fistulas may require a pancreatic duct stent, total parenteral nutrition (TPN), and bowel rest.

In the immediate postoperative period, patients should be monitored with sliding-scale insulin and tight glucose control. Patients are at risk for developing diabetes, and blood glucose should be monitored with subsequent follow-up. Malabsorption from deficiency of the exocrine pancreas can occur and should be treated with pancreatic enzyme replacement therapy (PERT) and diet modification. Patients with malignant tumors should have interval follow-up in 3-6 months with serial tumor markers and imaging to evaluate for disease recurrence.

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]