Management of the Uncinate Process in No-Touch Laparoscopic Pancreaticoduodenectomy

Summary

Complete resection of the uncinate process and mesopancreas is one of the most important and difficult processes in laparoscopic pancreatoduodenectomy (LPD). This article presents a method for managing the uncinate process in no-touch LPD using the median-anterior and left-posterior approaches to the superior mesenteric artery (SMA).

Abstract

Laparoscopic pancreatoduodenectomy (LPD) is a demanding abdominal operation that necessitates meticulous surgical skills and teamwork. The management of the pancreatic uncinate process is one of the most important and difficult processes in LPD because of its deep anatomical location and difficult exposure. Complete resection of the uncinate process and mesopancreas has become the cornerstone of LPD. In particular, it is even more difficult to avoid positive surgical margins and incomplete lymph node dissection when the tumor is located in the uncinate process. No-touch LPD, which is an ideal oncological operation process fitting the "tumor-free" principle, has been reported by our group previously. This article introduces the management of the uncinate process in no-touch LPD. Based on the multi-angle arterial approach, in this protocol, the median-anterior and left-posterior approaches to the SMA are used to correctly deal with the important vascular structure, the inferior pancreaticoduodenal artery (IPDA), in order to ensure the safe and complete excision of the uncinate process and mesopancreas. For the achievement of the no-touch isolation technique in LPD, the pancreatic head and the blood supply to the duodenal region must be severed at the very early stage of the operation; after that, the tumor can be isolated intact, resection can be performed in situ, and finally, the tissue can be removed en bloc. This paper aims to show the distinctive ways to manage the uncinate process in no-touch LPD and investigate the viability and safety of this approach. Moreover, the technique may increase the R0 resection rate.

Introduction

The pancreatic uncinate process is the protrusion from the bottom left of the pancreatic head that is situated behind the SMA and superior mesenteric vein (SMV)¹. The management of the uncinate process is a challenging area in pancreatic surgery due to its deep anatomy and challenging exposure; therefore, especially for pancreatic cancer located in the uncinate process, surgery is prone to result in a positive surgical margin, incomplete lymph node dissection, and poor prognosis². Therefore, improved surgical techniques and strategies are urgently required.

Most resection procedures of the pancreatic head and uncinate process are performed along the right side of the SMV and SMA³. Although this approach largely works for ampullary tumors, it has drawbacks for pancreatic head cancer, particularly for large tumors in the uncinate process². During the procedure, it is frequently required to spin and pull the SMV and SMA in order to expose them. The IPDA cannot be dissected clearly with such approaches, which usually results in bleeding or insufficient cleaning of the area. In this work, the authors describe an approach that can support the early control of the IPDA, which results in better bleeding control, less blood loss, and better dissection of the uncinate process.

Meanwhile, conventional laparotomy or laparoscopy pancreatoduodenectomy requires a Kocher maneuver for the wide mobilization of the duodenum and pancreatic head⁴. However, with this maneuver, the tumor cells have the potential capacity to metastasize via the portal vein (PV), as the surgeon might squeeze the tumor while holding it during surgery^4,5,6. The no-touch isolation technique is one of the popular concepts in pancreatoduodenectomy. Although it has not been proven by large clinical trials whether this surgical intervention could enhance the cancer-related prognosis of pancreatic cancer patients, the study of Hirota et al.⁷ reported the significance of no-touch technology in preventing cancer cell metastasis by using molecular markers (CEA mRNA) to detect cancer cells in the portal vein blood. In their study, the no-touch technique group had a lower spread rate of portal vein cancer cells and a higher 3 year survival rate than the conventional technique group. No-touch LPD has been reported by the team of the current authors previously as an ideal oncological operation process fitting the "tumor-free" principle^8,9.

This article presents the management of the uncinate process in no-touch LPD. The median-anterior and left-posterior approaches to the SMA were performed to deal precisely with the IPDA. To achieve the no-touch isolation technique in LPD, the blood supply to the duodenum and pancreatic heads must be cut off at the very early stage of the operation, after which the tumor can be isolated intact, resected in situ, and finally, removed en bloc.

The purpose and advantages of this strategy are to ensure the safe and complete excision of the uncinate process and mesopancreas based on a multi-angle arterial approach¹⁰. This article aims to explore the efficacy and safety of this technique for the management of the uncinate process in no-touch LPD, which might improve the R0 resection rate¹¹.

Protocol

This study was approved by the Ethics Committee of the Second Affiliated Hospital of Guangzhou University of Chinese Medicine, and informed written consent was obtained from the patients involved in this study.

1. Preoperative work-up

1. Perform the high-resolution contrast-enhanced CT^12,13 (see Table of Materials) to assess the tumor's extent and search for any abnormal vasculature.
2. Determine the inclusion and exclusion criteria for patients.
   1. Select patients meeting the following criteria: (1) a tumor located in the uncinate process that needs radical resection; (2) resectable cases.
   2. Exclude the following cases: (1) metastatic tumor; (2) patients with poor cardio-pulmonary function that may not tolerate laparoscopic surgery; (3) a tumor that has invaded the major vessels such as SMA, common hepatic artery (CHA), or celiac artery (CA).

2. Anesthetization steps

1. Use 0.3 µg/kg sufentanil, 3 µg/mL propofol, and 0.15 mg/kg cis-atracurium (see Table of Materials) for anesthesia induction.
2. Perform endotracheal intubation¹⁴ after the muscle relaxant takes effect.
3. Puncture and catheterize the radial artery and central vein under the guidance of ultrasound.
4. Use target-controlled infusion (TCI) of 1-2 µg/mL propofol, 1-3 ng/mL remifentanil, 1.53 µg/kg/min cis-atracurium, and sevoflurane (see Table of Materials) with an inhaled concentration of 1%-2% to maintain anesthesia, and keep the depth of anesthesia between 37 and 64 on the Nacrotrend Index¹⁵.
   NOTE: The Nacrotrend anesthesia monitoring system (see Table of Materials) is an anesthesia depth monitoring method developed in recent years. It obtains the original EEG, analyzes the changes in frequency and power in the EEG, integrates the factors of phase and harmonics, and expresses the anesthesia depth in the form of a value from 0-99.
5. Set the ventilator parameters to volume control ventilation mode, with a tidal volume of 8 mL/kg, an inhalation oxygen saturation of 60%, a gas flow of 2 L/min, and an end-expiratory carbon dioxide range of 35-45 mmHg.

3. Installation

1. Refer to our previously published⁸ article (Figure 1) for details on the patient position and trocar (see Table of Materials) location.
2. Surgeon position: Ensure that the operator surgeon and the first assistant stand on the patient's right and left sides, respectively. Ensure that the holder of the laparoscope stands between the patient's legs.

4. Surgery techniques

1. Inspect the peritoneal surfaces and intraperitoneal organs for any potential extrapancreatic metastases. Remove the greater omentum for better exposure, and open the lesser sac by severing the gastrocolic ligament.
2. Dissect the gallbladder triangle with an ultrasonic knife, then resect and sever the gallbladder artery and cystic duct, and finally, remove the gallbladder, and suspend the liver to expose the hepatoduodenal ligament and hilum (Figure 2).
3. Explore the gap between the pancreatic neck and the SMV in order to assess the surgical resectability.
   NOTE: The preferred gap is the space between the posterior neck of the pancreas and the SMV, which is difficult to open and expose if the tumor has invaded the SMV.
4. Suspend the transverse colon and its mesentery on the cephalic side to establish effective exposure.
5. Using the ileocolonic artery as the marker, open the transverse mesocolon. Protect the ileocolon artery and middle colonic artery.
6. Expose the second and third segments of the duodenum, dissect along the right side of the SMV, and separate the second and third segments of the duodenum from the transverse mesocolon.
7. Expose the main trunk of SMV and the proximal-dorsal jejunal vein (PDJV) between the SMV and SMA (Figure 3), and then ligate and dissect the inferior pancreaticoduodenal vein (IPDV).
   NOTE: Be careful not to apply too much pressure, as this might cause the IPDV to hemorrhage.
8. Perform the median-anterior approach to the SMA following steps 4.8.1-4.8.4.
   1. Start the median-anterior approach to the SMA from the inferior colon region.
   2. Pull the SMV just to the right, widen the operation field, and expose the SMA pulsation to determine its trajectory.
   3. Expose the right half of the SMA, and dissect outside the arterial sheath of the SMA on the anterior-right margin in order to separate the SMA from the pancreatic mesopancreas.
      NOTE: The middle colonic artery (MCA), which runs along the side of the vascular arch of the margin of the transverse mesocolon, can be directly linked to the trunk of the SMA in cases where it is difficult to identify the SMA, such as when it is difficult to assess arterial visual pulsation in obese patients. The best place to locate and identify the trunk of the SMA is where the MCA begins in the inferior colonic region. If required, color ultrasound assistance could be used.
   4. Through the median-anterior approach to the SMA approach, expose the main branches of the IPDA or jejunal artery (JA) along the right side of the SMA, and then conduct a further follow-up to confirm them (Figure 4).
      NOTE: The authors' experience is that IPDA and JA can be effectively identified by the subsequent left-posterior approach to the SMA.
9. Perform the left-posterior approach to the SMA following steps 4.9.1-4.9.9.
   1. Place the entire small bowel to the right side to facilitate space exposure between the fourth segment of the duodenum and the inferior vena cava.
   2. Dissect the fusion fascia, and expose the left renal vein (LRV) to establish the posterior space of the SMA.
   3. Use an ultrasonic scalpel to dissect the ligament of Treitz between the beginning part of the jejunum and the mesentery of the transverse colon.
   4. Use a stapler to divide the proximal jejunum.
   5. Place an Fr8 catheter for suspending the dorsal sides of the SMA and SMV.
   6. To facilitate SMA dissection on its periadventitial plane on the anterior-left border and its detachment from the mesopancreas, pull the catheter to the upper right side. Establish an effective exposure space at the left-posterior aspect of the SMA (Figure 5).
   7. Trace up the SMA to the root along the first jejunal artery (FJA).
   8. Dissect the SMA on its periadventitial plane on the anterior-left margin in order to separate it from the pancreatic mesopancreas. Circumferentially dissect the SMA.
   9. Ligate and dissect the IPDA (Figure 6). Sacrifice the FJA if it is involved in the tumor.
10. Using the median-anterior and left-posterior SMA approaches, separate the SMA and SMV from the uncinate process and mesopancreas completely (Figure 7).
11. Return to the superior region of the colon following steps 4.11.1-4.11.16.
    1. Draw the proximal jejunum from the dorsal of the SMA to the right.
    2. Reveal the right gastrointestinal vein, the collateral right colonic vein, and the SMV trunk using an ultrasonic knife (see Table of Materials).
    3. Expose Henle's gastrocolic trunk vein to disconnect its distal and proximal ends on the right side of the SMV trunk.
       NOTE:Find Henle's gastrocolic trunk vein along the right reticular vein on the right side of the SMV.
    4. Divide the stomach 3-5 cm away from the pylorus using a stapler device (see Table of Materials).
    5. Expose the CHA at the superior margin of the pancreatic neck.
    6. Dissect along the CHA toward the first hepatic hilar to reveal the proper hepatic artery (PHA) and the right gastric artery (RGA). Ligate and sever the RGA.
    7. Use laparoscopic bulldog clamps (see Table of Materials) to temporarily occlude the common bile duct (CBD) after separating the CBD.
    8. Dissect the hepatoduodenal ligament. Execute a lymphadenectomy along the CHA, PV, and PHA.
    9. Ligate and dissect the right gastric artery.
    10. Locate the gastroduodenal artery (GDA) at the junction of the PHA with the CHA, and meticulously ligate or suture (5-0, see Table of Materials) the GDA to reduce the possibility of an ensuing erosion or hemorrhage.
    11. Explore the tunnel between the pancreatic neck and the SMV. Ligate and dissect the dorsal pancreatic artery (DPA).
    12. Place two Fr14 catheters to block the pancreatic neck blood supply in order to reduce bleeding (Figure 8).
    13. Dissect the parenchyma of the pancreatic neck using scissors. Suture (5-0, see Table of Materials) the bleeding point of the resection surface.
        NOTE: Examine a fast-frozen pathological specimen of the pancreatic stump to prove the negative margin.
    14. Suspend the splenic vein (SV) to establish exposure after the left first branch of the SMV has been ligated and dissected (Figure 9).
    15. Ligate and dissect the uncinate process artery behind the SV. Identify and retain the alternative right hepatic artery originating from the SMA from the uncinate process artery.
        NOTE: At this point, all the blood supplies to the tumor are completely occluded.
    16. Ligate and dissect the branches of the PV.
12. Using the Kocher maneuver, cut off the lymphatics, and dissect the duodenum from the retroperitoneum. Resect the tumor in situ, and remove it en bloc following the oncologic principles of no-touch^16,17.
13. Use Child's method for the reconstruction of the digestive tract^8,18.
14. Perform a single-layer running suture hepaticojejunostomy from end to side using 4-0 absorbable sutures. Utilize an internal stent to perform a duct-to-mucosal, end-to-side pancreaticojejunostomy.

5. Postoperative management

1. If the gastric tube drainage is <200 mL, remove the tube on the next day.
2. Start appropriate physical exercise if the vital signs are stable and the patient is generally in good condition.
3. Assess the amylase level of the drainage liquid on postoperative day 3, and review the abdominal CT on postoperative day 7. Remove the drainage tubes if there is no evidence of biochemical leakage, lymphatic fistula, or hemorrhage.

Results

A male patient aged 59 years old with symptoms including upper abdominal pain and jaundice was hospitalized in our department. He had no previous medical history and a relatively moderate normal body mass index (23.94 kg/m2). A contrast-enhanced CT scan was performed, and a tumor with a diameter of approximately 5.5 cm x 4.6 cm x 6.3 cm was found at the head and uncinate process of the pancreas (Figure 10). No evidence of distant metastasis was found, and percutaneous transhepatic cholangica...

Discussion

With intestinal rotation, the ventral pancreas flips to the dorsal side and unites with the dorsal pancreas throughout the development of the human embryo, and the ventral pancreas also grows into the lower portion of the pancreatic head and the uncinate process¹. The pancreatic uncinate process is described as the protrusion from the bottom left of the pancreatic head that is situated behind the SMA and the SMV¹.

In the meantime, the mesopancre...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
3D Laparoscope	STORZ	TC200,TC302
Cisatracurium Besylate Injection	Hengrui Pharma	H20183042
Dual-source dual-energy  CT	SOMATOM	Definition FLASH
Echelon Flex Powered Plus Articulating Endoscopic Linear Cutter and Endopath Echelon Endoscopic Linear Cutter Reloads with Gripping Surface Technology	Ethicon Endo-Surgery	ECR60G/GST60G
ENDOPATH XCEL Trocars	Johnson & Johnson	CB5LT/CB12LT
HARMONIC ACE Ultrasonic Surgical Devices	Ethicon Endo-Surgery	HAR36
Laparoscopic bulldog clamps	Aesculap	FB367R,FB369R
Ligating Clips	Teleflex Medical	5,44,22,05,44,23,05,44,000
Nacrotrend anaesthesia monitoring system	Monitor Technik,Bad Bramsted
PROLENE Polypropylene Nonabsorbable Suture/5/0	Johnson & Johnson	W8556
Propofol Injectable Emulsion	Aspen Pharma Trading Limited	H20171275
Remifentanil Hydrochloride for injection	Humanwell Healthcare	H20030197
Sevoflurane for Inhalation	Hengrui Pharma	H20070172
Sufentanil Citrate Injecton	Humanwell Healthcare	H20054171
Trocars	AOFO	FQ-D1/5.5mm 10.5mm
Ultrasonic Surgical & Electrosurgical Generator	Ethicon Endo-Surgery	GEN11CN