Pylorus-Resecting Pancreaticoduodenectomy

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Executive Summary

Pylorus-resecting pancreaticoduodenectomy (PrPD) is a surgical evolution designed to address the high incidence of delayed gastric emptying (DGE) associated with pylorus-preserving pancreaticoduodenectomy (PpPD). While PpPD was originally introduced to minimize postgastrectomy syndromes, the denervation and devascularization of the pyloric ring frequently resulted in significant postoperative complications and prolonged hospital stays.

PrPD involves the targeted resection of the pylorus ring while preserving nearly the entire stomach, including the antrum. Clinical evidence, including randomized controlled trials (RCTs) and meta-analyses, suggests that PrPD significantly reduces DGE rates—in some cases from 17.2% to 4.5%—without compromising long-term nutritional status or significantly increasing the risk of dumping syndrome. This document details the technical procedures, clinical rationale, and comparative outcomes of PrPD as a primary treatment for periampullary neoplasms and pancreatic head cancer.

1. Historical Context and Evolution

The surgical treatment of pancreatic and periampullary cancer has undergone several major iterations:

  • Conventional PD (1912–1941): Developed by Kausch and refined by Allen Oldfather Whipple, initially as a two-stage operation.

  • Pylorus-Preserving PD (PpPD) (1944–1970s): Introduced by Watson and popularized by Traverso and Longmire to reduce postgastrectomy syndromes like dumping and bile reflux.

  • Subtotal Stomach-Preserving PD (SSPPD) (2007): Introduced by Hayashibe to address DGE, though the specific resection margins remained poorly defined.

  • Pylorus-Resecting PD (PrPD) (2011): Formally designed to resect only the pylorus ring to prevent pylorospasm while maintaining the stomach’s pooling capacity.

2. Technical Procedure of PrPD

The PrPD procedure is characterized by specific vascular approaches and precise resection margins to optimize oncological outcomes and minimize complications.

2.1 Mesenteric Approach (Artery-First)

This approach is utilized when superior mesenteric artery (SMA) involvement is suspected, allowing for early determination of resectability.

  • Vascular Identification: The mesentery of the jejunum is resected between the Treitz ligament and the third portion of the duodenum to identify the superior mesenteric vein (SMV) and SMA.

  • Ligation: The inferior pancreaticoduodenal artery (IPDA) is ligated early to minimize bleeding and provide better exposure of the posterior connective tissues.

  • Nerve Plexus Management: If the tumor does not invade the SMA nerve plexus, it is preserved. If abutment is present, the plexus is resected to ensure negative surgical margins.

2.2 Resection of the Pylorus Ring

The primary distinction of PrPD is the specific division of the stomach.

  • Margins: The stomach is divided immediately adjacent to the pylorus ring, preserving the nearly total stomach including the antrum.

  • Nerve and Vessel Dissection: The right gastric artery is dissected at the root, and the first pyloric branch is dissected along the lesser curvature. The pyloric branch of the vagal nerve and associated lymph nodes are also removed.

2.3 Lymph Node Dissection and Pancreas Transection

  • Hepatoduodenal Ligament: Adipose tissue is cleared around the common and proper hepatic arteries. Precise identification of the right hepatic artery is critical as it generally runs behind the bile duct.

  • Bile Duct Management: The duct is cut at the common hepatic duct level, and the margin is pathologically diagnosed for cancer cells.

  • Transection: The pancreas is sharply transected with cautery on the left side of the portal vein. Hemostasis of the remnant stump is achieved using 5-0 prolene to prevent pancreatic fistula.

2.4 Reconstruction Phase

  • Pancreaticojejunostomy: A duct-to-mucosa anastomosis is performed using a single layer of interrupted absorbable stitches.

  • Choledochojejunostomy: Constructed as a single-layer anastomosis using interrupted stitches without a stent.

  • Gastrojejunostomy: Performed via an antecolic route using a two-layer anastomosis (inner layer: 4-0 PDS-II; outer layer: 3-0 silk).

3. Clinical Impact on Delayed Gastric Emptying (DGE)

DGE remains a primary complication of PpPD, attributed to factors such as antroduodenal ischemia, gastric atony from vagotomy, and specifically, pylorospasm caused by denervation of the pyloric ring. PrPD aims to eliminate these factors by removing the ring itself.

Comparative Study Outcomes

The following table summarizes key findings from comparative studies between PpPD and PrPD/SSPPD:

Clinical Evidence Analysis

  • DGE Reduction: Most studies and two meta-analyses confirm that PrPD significantly reduces the incidence of DGE compared to PpPD.

  • Surgical Modification: Research by Nakamura et al. suggests that a side-to-side gastrojejunostomy on the greater curvature further reduces DGE (2.5%) compared to end-to-side anastomosis (21.3%).

  • Discrepancies: The RCT by Matsumoto et al. found no significant difference, which may be attributed to the exclusion of pancreatic cancer patients who typically require more invasive regional lymph node dissection.

4. Long-Term Outcomes and Quality of Life

As survival rates for pancreatic cancer improve, long-term nutritional status and quality of life (QOL) have become critical metrics.

  • Dumping Syndrome: Despite concerns that resecting the pylorus ring would increase dumping syndrome, studies show a very low incidence (1.6% in a 2-year follow-up), typically manageable through diet.

  • Nutritional Status: PrPD is considered equally effective to PpPD regarding long-term nutritional markers, including serum albumin levels, cholesterol, and BMI.

  • Superiority in Specific Cases: Fujii et al. found that SSPPD patients with pancreatic cancer had significantly higher serum albumin and total lymphocyte counts one year postoperatively compared to PpPD patients. This is attributed to a larger gastric outlet diameter, which facilitates better oral intake.

5. Conclusion

PrPD is a recommended procedure for treating periampullary neoplasms and pancreatic head cancer. By resecting only the pylorus ring, the procedure maintains the stomach's reservoir function while effectively mitigating the risk of delayed gastric emptying. While current meta-analyses support the efficacy of PrPD in reducing postoperative complications, ongoing research continues to evaluate its impact on long-term nutritional status and overall quality of life.