Perioperative management - Cephalic pancreatoduodenectomy with Blumgart anastomosis and biliopancreatic separation (Merheim technique)

•    resection of an ampullary The current standard in surgery for malignant tumors of the pancreatic head is Traverso-Longmire pylorus-preserving pancreatoduodenectomy.

Despite the poor overall prognosis of these tumors, surgery is the only potentially curative option.

In principle, if malignancy is present or suspected for good reason, resection of the pancreatic head is always indicated if there is at least the prospect of total tumor resection both preoperatively and intraoperatively, and if the patient is in adequate general condition to withstand this procedure.

The most common malignant tumor of the pancreas is ductal adenocarcinoma (85%), affecting in 65% of cases the pancreatic head.

Other indications:

• Distal cholangiocarcinoma/ampullary carcinoma
• Duodenal carcinoma
• Large ampullary or periampullary duodenal adenomas
• Benign/cystic tumors of the pancreatic head
  • Mucinous-cystic neoplasm (>3 cm)
  • Solid pseudopapillary neoplasm
  • Intraductal papillary mucinous neoplasm (except accessory duct IPMN <2 cm)
• Chronic pancreatitis with complications, in particular with distal CBD stenosis
• “Dilemma” cases (where diagnostic imaging and clinical examination are unable to differentiate reliably between inflammatory and malignant pancreatic head tumor)
• Hereditary gastrinomas in MEN-1 disease (multiple duodenal gastrinomas)
• Pancreatic head metastases

The main difference versus the classic Kausch-Whipple procedure is the preservation of the stomach and its neurovascular supply. There is no difference between these two procedures with regard to mortality, morbidity and oncological radicality. The excision margin for an R0 resection is not the resection margin of the stomach, but that of the posterior, retroperitoneal pancreas.

The benefit of the pylorus-preserving technique is a shorter operating time and less blood loss. Moreover, patients maintaining their physiological ability of gastric emptying do better in terms of absorption, nutrient utilization and postoperative weight gain.

 In case of infiltration of large veins (superior mesenteric vein, splenic vein or portal vein), resection should be attempted, if necessary with vascular reconstruction, since preoperative diagnostic work-up generally cannot differentiate between inflammatory adhesions and tumor infiltration.  Patients appear to benefit from vascular resection if R0 resection is successful.

Given the current limited study data, the resection of visceral arteries to achieve R0 resection is at the discretion of the surgeon.

The indication for surgical resection is determined shortly after diagnosis, particularly in case of a potentially resectable finding in icteric patients. Preoperative endoscopic bile duct drainage should only be considered in patients with manifest secondary complications of jaundice (impaired plasmatic coagulation, liver synthesis disorders, reduced cellular defenses, purulent cholangitis) to gain time and assure better baseline conditions for surgery. In all other cases, preoperative bile duct drainage, whether TPCD (transpapillary cholangiographic drainage) or PTCD (percutaneous-transhepatic cholangiographic drainage), should be avoided due to the increased postoperative morbidity.

Comorbidity is another important factor when determining the indication. Patients with severe cardiovascular comorbidities run a significantly increased risk of surgical complications. Nowadays, old age in itself is no longer a contraindication for resection of the pancreatic head.

For locally advanced tumors of questionable resectability, neoadjuvant radiochemotherapy can be attempted (if possible in trial settings) to allow resection with curative intent.

Lymphadenectomy targets the regional lymph nodes of the duodenum and pancreatic head.  More extensive lymphadenectomy does not improve survival. Therefore, extended lymph node dissection is controversial because of the higher complication rate. Vascular skeletonization along the aorta and superior mesenteric artery with resection of nerve tissue can result in persistent gastric emptying disorders and severe diarrhea and malnutrition.

The case in the video involves oncological carcinoma.

• Malignancy of the pancreatic head with proximal infiltration of the superior mesenteric  artery or celiac trunk
• Local tumor no longer resectable due to mesenteric root infiltration
• Nonresectable distant metastasis
• Portal vein thrombosis and other disorders with marked venous collateral circulation (liver cirrhosis)
• Patients with severe cardiovascular comorbidities, for whom anesthesia alone poses a risk (e.g., NYHA class II  with high-grade carotid ste

History / Clinical findings:

• No characteristic cardinal symptom, unspecific with loss of appetite, bloating, indigestion, weight loss
• Painless jaundice in pancreatic head tumors
• Epigastric and back complaints if tumor is in the pancreatic body/tail
• New-onset diabetes mellitus
• Cholestasis, cholangitis, obstructive pancreatitis, Courvoisier sign (enlarged prominent nontender gallbladder), palpable tumor, previous surgery

Diagnostic lab panels:

• Blood count; CRP; blood sugar; oGTT (oral glucose tolerance test); serum lipase/amylase
• Tumor marker CA 19-9 (independent predictor of poorer overall survival)
• Tumor marker CEA (particularly in EUS [endoscopic ultrasound ] guided needle biopsy of cysts)
• Genetics: PRSS1; SPINK1; PSTI; CFTR (in young patients to rule out hereditary origin - strict indication because of the high expense!)

Diagnostic imaging

Diagnosis of a pancreatic head tumor is based on morphological changes seen on imaging. The laboratory, endoscopy and biopsy findings are of less diagnostic value. The most common imaging modality is CT, and increasingly also MRI with MRCP (magnetic resonance cholangiopancreatography). Preoperative differential diagnosis can be challenging and often is only established intraoperatively or even has to wait for the definitive histology of the specimen.

• Transcutaneous ultrasonography: Basic diagnostic workup with good noninvasive visualization of the pancreatic parenchyma, any enlargement of the pancreatic will also be detected. Additional assessment of the portal vein system on color Doppler ultrasound. Ultrasound contrast media can contribute to the differential diagnosis of inflammatory versus tumorous and cystic tumor versus pseudocysts. Moreover, detection of cholestasis; cholecystolithiasis; liver metastases; ascites.
• CT or MRI: Confirmation of the suspected tumor; assessment of local resectability (vascular infiltration); distant metastasis (liver); vascular supply to the liver/epigastrium (e.g., abnormalities such as atypical right hepatic artery); pancreatic calcifications; pancreatolithiasis; ascites.

Visualization of the biliary or pancreatic duct system is needed only in unclear cases. ERCP and MRCP are suitable modalities to that effect. The "double duct sign" (simultaneous stenosis/obstruction of the pancreatic duct and bile duct) is considered pathognomonic for cancer.

• MRCP (magnetic resonance cholangiopancreatography): Noninvasive imaging of the bile and pancreatic duct system. More sensitive than ERCP in detection of solid mural changes ("mural nodules")
• ERCP: Because of the potential complications (pancreatitis, bleeding, perforation), if possible only for therapeutic interventions, otherwise MRCP or EUS.
• Interventional relief of the bile duct system only in the case of unresectability or delayed surgery, otherwise immediate surgery
• EUS (endoscopic ultrasound) Mass in the head of the pancreas, assessment of local tumor extent and local lymph nodes (LN) (LNs >1 cm are suggestive of malignancy),puncture (fine needle aspiration of cyst fluid) and biopsy, if necessary.
• Ruling out lung metastases through chest CT

Gastroduodenoscopy:

• Histological confirmation of (peri)ampullary carcinoma is possible
• Ruling out/extent of duodenal polyps in pylorus-preserving procedures
• Transpapillary secretion of viscous mucus highly suggestive of IPMN

Histological confirmation of the tumor is not needed preoperatively if the suspicion of tumor is well founded, but is needed before initiating neoadjuvant radiochemotherapy or palliative chemotherapy in the metastatic stage.

• Blood typing
• Readying 4 typed packed RBCs
• Jaundiced patients: parenteral vitamin K (Konakion®) for 2-3 days preoperatively regardless of coagulation status
• Preoperative endoscopic bile duct drainage only in patients with manifest secondary complications of icterus (impaired plasmatic coagulation, liver synthesis disorders, reduced cellular defenses)
• Gastric outlet stenosis: preoperative nasogastric tube

Major surgery, therefore provide patient with relevant information well in advance (>24 h; it is best to inform at initial visit).
Always provide diagrams to explain the postoperative anatomy!
Sequelae of the operation:

General

• Secondary healing
• Thromboembolism
• Pneumonia
• Lymphatic fistula
• Injury to adjacent structures (bowel, vessels, nerves, other organs)
• Extending the scope of surgery at surgeon’s discretion
• Redo procedures
• Possible long-ICU stay to manage complications
• Bleeding/secondary bleeding: allogeneic blood transfusion needed in approx. 50% of cases

Specific

• Pancreatic fistula
• Delayed gastric emptying
• Bile leakage/bilioma
• Suture line failure/stenosis
• Necrosis of the pancreatic remnant
• Endocrine and exocrine pancreatic insufficiency, possibly requiring dietary changes
• Insulin-dependent diabetes mellitus (lifelong)
• Peptic jejunal ulcers
• Intermittent cholangitis in case of bilioenteric anastomosis