Surgical Tips of Right Posterior Superior Mesenteric Artery Approach for Pancreatoduodenectomy

Summary

This protocol details the right posterior superior mesenteric artery approach during pancreatoduodenectomy. By dissecting the peripancreatic plexus from a caudal direction before dissecting the superior mesenteric vein groove, this technique enhances anatomical clarity, resulting in minimizing intraoperative bleeding. Standardizing this approach ensures surgical reproducibility and facilitates safe vascular resections.

Abstract

Pancreatoduodenectomy (PD) is a complex operation, particularly when tumors involve major vessels, including the portal vein and superior mesenteric vein (SMV) or major arteries. To achieve radical surgery, venous resection is often required, and with advancements in neoadjuvant therapy, aggressive surgical approaches, including arterial divestment and resection, are becoming more common. Ideally, a standardized technique should be applied for resectable tumors. In our institution, the right posterior superior mesenteric artery (SMA) approach is routinely performed. This study presents the details of the right posterior SMA approach.

The protocol outlines the patient selection criteria, surgical positioning, and step-by-step technical procedures. The right posterior SMA approach begins with exposing the SMV, followed by dissection of the peripancreatic plexus (PLph II) posteriorly from a caudal direction. After anterior dissection of the SMV groove and PLphI, the specimen is removed. This technique enables a clear anatomical boundary, facilitating better visualization and safer resection. Standardizing this approach might enhance oncological outcomes, improve surgical reproducibility, and reduce intraoperative bleeding.

Introduction

Pancreatic ductal adenocarcinoma (PDAC) frequently invades major vessels, particularly the superior mesenteric-portal vein (SMPV), due to the anatomical proximity of the pancreatic head to these structures¹. Therefore, safely dissecting the tumor from surrounding tissues, including major vessels, is a critical step in achieving curative resection. To facilitate safe dissection and evaluate resectability, various approaches have been proposed to access the superior mesenteric artery (SMA) before pancreatic head resection. These are collectively referred to as "artery-first approaches"².

Among these, the right posterior SMA approach has been introduced as one of the artery-first approaches. This technique is adopted as a method to dissect the nerve plexus around the SMA before dividing the SMV groove. By incorporating this concept, the procedure can be standardized not only for tumors without vascular invasion but also for those involving the SMPV. Although the SMA is not confirmed at the initial step, this technique incorporates the conceptual advantages of the artery-first strategy by preparing the posterior dissection plane toward the SMA from the early phase of surgery.

We hypothesize that by standardizing the posterior approach to the SMA, we can always be prepared for SMPV resection, even in cases where venous involvement is not anticipated on preoperative imaging. Furthermore, this approach allows for complete clearance of the soft tissue between the celiac axis and the SMA in all cases-a procedure known as triangle dissection³. In this study, we present a representative case to illustrate the procedural steps of the right posterior SMA approach.

Protocol

The protocol follows the guidelines of the Human Research Ethics Committee of Umeå University Hospital (Institutional Review Board: 2021-02787). In this session, the retropancreatic plexus of the pancreatic head I and II (PLphI, II), and the nerve plexus around the SMA (PLsma) are defined by the General Rules for the Study of Pancreatic Cancer by the Japan Pancreas Society⁴.

1. Patient selection

1. Include patients eligible for curative resection of tumors in the pancreatic head or the periampullary region undergoing pancreatoduodenectomy (PD).

2. Patient positioning

1. Position the patient, under general anesthesia, supine on the operating table. Extend the arms, and close the legs.

3. Surgical technique

1. After an upper abdominal midline incision, explore the abdominal cavity to rule out peritoneal carcinomatosis and liver metastases. Then, perform an extended Kocher maneuver, which exposes the left renal vein to allow visualization of the interaortocaval space.
2. Dissect the mesocolon off the third portion of the duodenum and the uncinate process of the pancreas, with identification of the lateral wall of the SMV. Remove the aortocaval lymph nodes and send them for frozen section analysis or definitive pathological examination, depending on local protocol.
3. At this stage, assess the origin of the superior mesenteric artery (SMA). If vascular involvement is identified or if a superior mesenteric vein (SMV) resection is expected, perform a Cattell-Braasch maneuver⁵.　Additionally, in patients with a high body mass index or a limited surgical field, the Cattell-Braasch maneuver can enhance exposure and facilitate a safe resection.
4. Dissect the gastrocolic ligament and greater omentum to expose the pancreatic head. At this point, ligate and divide the gastroepiploic vessels (artery and vein). The dissection between the mesocolon and the duodenum allows for the identification of the SMV. Then, trace the SMV to the origin of Henle's trunk, which may be fully resected or preserved depending on the case. Follow up the SMV to the inferior border of the pancreatic neck.
5. Now, direct the attention to the hepatic pedicle. After identifying Calot's triangle, perform an anterograde cholecystectomy. If not required, leave the cystic duct intact to facilitate the preparation of the common bile duct.
6. Dissect the common bile duct circumferentially, and perform a lymphadenectomy of the hepatic pedicle. Particular care must be taken when removing lymph nodes from the right side of the hepatic pedicle, as an aberrant right hepatic artery or a replaced right hepatic artery originating from the SMA may be at risk of injury during lymph node dissection.
7. Clear the hepatic pedicle completely, and isolate its structures with loops: the portal vein, the proper hepatic artery, and the common bile duct.
8. Then, proceed with the dissection from the proper hepatic artery toward the celiac trunk. Identify the gastroduodenal artery (GDA) and perform a lymphadenectomy of the common hepatic artery.
9. At this stage, pay special attention to the coronary vein, and preserve it if possible. Depending on the tumor's location, perform a transection of the duodenum or stomach. If no significant infiltration or technical challenges arise, shift attention to the GDA, ligate, and resect it.
10. Following the resection of the GDA, expose the pancreatic neck fully, along with the passage of the portal vein beneath the pancreas. Then, create a retropancreatic tunnel carefully using gentle dissection from both the superior and inferior edges of the pancreas at the previously prepared site. Once the tunnel is established, pass a loop around the pancreatic neck to facilitate traction.
11. Divide the pancreas at the level of the neck, above the vein. Place two hemostatic stitches with non-absorbable threads at the edge of the pancreas, and then divide the tissue. Send a frozen section of the pancreas to confirm clear margins.
12. Then, direct attention to the jejunum, transect it after the ligament of Treitz. Divide the ligament, and free the first jejunal loop completely from the mesentery, making it ready to pass behind the mesenteric root. Retract the specimen side of the small intestine to the right side.
13. Begin the right posterior SMA approach with proper exposure of the surgical field and specimen.
    1. Let the first surgeon hold the specimen (duodenum and pancreas) with their less dominant hand, and have the first assistant straighten the mesenteric root to stretch the SMA (Figure 1).
    2. With this positioning, start the dissection by releasing the first jejunal vein from the specimen, using a sealing device to separate and ligate the small venous branches draining into the first jejunal vein. If the first jejunal vein is involved by the tumor, resect it.
    3. Once the first jejunal vein is released, proceed with dissection from the left side of the SMA in a clockwise direction, dividing the PLphII and progressively exposing the SMA (Figure 2).
       ​NOTE: The PLsma is preserved in most cases; however, if the tumor is close to the SMA, the involved portion of the PLsma is resected to achieve complete divestment.
    4. After resecting PLphII, leave PLphI down to the root of the SMA. Subsequently, dissect the SMV groove and PLphI from the anterior side, and remove the specimen. In this phase, achieve triangle dissection under clear and safe visualization³.
    5. In cases of tumor invasion into the SMV or PV, after PLphI resection, remove the specimen following combined portal vein resection. This maneuver allows the surgeon to operate within a safe plane, ensuring complete removal of the mesopancreas while leaving only the vein attached to the specimen.
14. Here, the reconstruction after pancreatoduodenectomy follows the classic Child reconstruction technique. Perform the pancreatico-jejunostomy (PJ) using a duct-to-mucosa technique. Approximately 20 cm from this, create a hepaticojejunostomy (HJ), followed by an antecolic either a duodenojejunostomy or gastrojejunostomy.
15. Place two soft silicone drains through abdominal incisions. Position the right drain in the aortocaval space with its tip below the HJ, while the left drain goes behind the stomach with its tip above the PJ. Perform the fascia closure with a running suture using slowly absorbable monofilament.

Results

A 69-year-old male underwent computed tomography (CT) during an episode of pancreatitis, revealing main pancreatic duct (MPD) dilatation measuring 7 mm in the head and 6 mm in the body, along with a small branch-duct IPMN in the head. Based on these findings, a diagnosis of mixed-type intraductal papillary mucinous neoplasm (IPMN) was made. Tumor markers were within normal limits. Endoscopic retrograde cholangiopancreatography (ERCP) with SpyGlass (direct visualization) cholangioscopy identified a fish eye papilla, confi...

Discussion

The right posterior SMA approach has several advantages in pancreaticoduodenectomy (PD), particularly in cases requiring vascular resection. By dissecting the PLph I and II from a caudal direction and establishing a clear anatomical boundary early in the procedure, this technique enables better visualization and safer resection^6,7. Additionally, identifying and managing the first jejunal vein early in the dissection facilitates a smooth transition to SMV isolatio...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
DaBakey foreceps 30 cm	Aesculap	FB405R
Bipolar scissors	Ethicon	BP340	Main dissection tool
Bipolar scissors' cable	Ethicon	BP940	Cable for the bipolar scissors
OrbEye	Olympus	OME-V200	4K camera, for broadcasting (to conference room) and recording
Peang Heiss gracile 18 cm	Stille	1834
Powerseal	Olympus	PS-0523CJDA	Bipolar heat instrument
Sony monitor 55 inches	Olympus	LMD-XH550ST	Belongs to OrbEye system
Sony recorder	Olympus	HVO-4000ST	Belongs to OrbEye system
Thompson retractor system	Thompson	1900181	Self refractor system