title: Posterior 'superior mesenteric artery first' approach for resection of locally advanced pancreatic cancer.
abstract: BACKGROUND
  En bloc resection of the superior mesenteric vein (SMV), portal vein (PV), and/or splenic vein (SV) with concomitant venous reconstruction is required in 11-65 % of cases of locally advanced pancreatic cancer.1 Early retropancreatic dissection of the superior mesenteric artery (SMA) from behind the pancreatic head utilizing an 'artery first' approach has been reported to be an efficient and safe approach to pancreaticoduodenectomy when SMA involvement is suspected.2 Additionally, this technique has been shown to reduce blood loss and result in shorter PV clamp times.3 While there are multiple variations to 'artery first' resection,4 this video will illustrate the critical steps of using the 'posterior approach' in patients with locally advanced pancreatic cancer. This approach has the benefit of early identification of a replaced right hepatic artery, but may be difficult in obese patients or those with extensive peripancreatic inflammation. These difficulties may be overcome by utilizing an 'inferior supracolic (anterior) approach', but this necessitates early division of the pancreatic neck and stomach.5 METHODS: Select video clips were compiled from several pancreatoduodenectomies to demonstrate this technique. A variety of bipolar devices were utilized for dissection depending on surgeon preference. All patients were diagnosed with locally advanced pancreatic cancer by Americas Hepato-Pancreato-Biliary Association/Society of Surgical Oncology (AHPBA/SSO) consensus criteria, confirmed by biopsy, and completed neoadjuvant chemotherapy. Patients were restaged by pancreas protocol computed tomography scan at the end of chemotherapy and offered local resection if the tumor did not progress and they were medically fit. No Institutional Review Board approval was required.
  
  
  RESULTS
  The operation begins by dividing the attachment of the transverse mesocolon to the right perinephric area and extending this down to the white line of Toldt, followed by a wide Kocher maneuver. The lateral attachments to the pancreatic head are then divided, thereby exposing the left renal vein. The lesser sac is entered directly over the uncinate, allowing for a full visceral rotation of the pancreatic head, and further facilitating exposure of the left renal vein. In the setting of malignancy, the SMA may now be palpated posterior to the pancreatic head and/or neck to confirm it is free of tumor. If tumor is invading the SMA, the pancreaticoduodenectomy is aborted prior to performing any gastrointestinal or pancreatic transections. If the SMA is free, the dissection is then carried on to the inferior aspect of the pancreatic neck. Here the SMV (jejunal and ileal branches), middle colic vein, and the gastroepiploic vein are identified and the latter is ligated and transected. Following this, dissection of the portal structures (hepatic arteries, gastroduodenal artery, common bile duct, and PV) is performed. The jejunum is then divided, the ligament of Treitz is taken down, and the jejunum is then mobilized to the patient's right side. This allows for clear visualization of the pancreatic head/uncinate/SMV relationship. At this point, proximal and distal control of the PV, SMV, and SV should be obtained using vessel loops or umbilical tape. The dissection then proceeds laterally along the SMA border (posterior to the pancreatic head). This is often facilitated by use of a bipolar sealing device due to a rich lymphovascular network. Once the lateral border of the SMA is clearly exposed, dissection along its longitudinal axis is performed utilizing the jejunum for traction. Following this dissection, larger vessels such as the inferior pancreaticoduodenal artery can be more readily identified and ligated to fully mobilize the pancreatic head. After the head is completely separated from the SMA, the neck is divided. This leaves the specimen attached solely by the PV and SMV, which greatly facilitates venous resection and reconstruction when necessary.
  
  
  CONCLUSIONS
  The 'artery first' approach has been shown to be safe and feasible in pancreatic resections. This technique should be considered whenever tumor is thought to involve the SMV and/or PVs as a means to facilitate safe venous resection and reconstruction while preserving sound oncologic principles.
authors.affiliation: HPB Service, Section of General, Thoracic and Vascular Surgery, Virginia Mason Medical Center, Seattle, WA, USA, bart.rose@vmmc.org.
authors.forename: J Bart
authors.initials: JB
authors.lastname: Rose
authors.forename: Flavio
authors.initials: F
authors.lastname: Rocha
authors.forename: Adnan
authors.initials: A
authors.lastname: Alseidi
authors.forename: Scott
authors.initials: S
authors.lastname: Helton
mesh_terms: D004210:Dissection / Q000379:methods*; D006801:Humans; D017538:Mesenteric Artery, Superior / Q000601:surgery*; D010190:Pancreatic Neoplasms / Q000601:surgery*; D016577:Pancreaticoduodenectomy / Q000379:methods*