Enteric Ductal Drainage for Chronic Pancreatitis
Executive Summary
The primary objective of enteric ductal drainage in chronic pancreatitis is the decompression of a markedly dilated and obstructed main pancreatic duct. This intervention aims to alleviate "pancreatic compartment syndrome"—a state where high ductal pressure compromises the pancreatic parenchyma—thereby resolving chronic pain and preventing further loss of endocrine and exocrine function. The modern standard, the Modified Puestow Procedure (Lateral Pancreaticojejunostomy), evolved from earlier techniques by Duval and Puestow to a side-to-side anastomosis that preserves the pancreatic tail. Successful outcomes depend on meticulous preoperative evaluation, precise identification of the ductal "trough" through a fibrotic pancreas, and the creation of a tension-free Roux-en-Y anastomosis.
Clinical Indications and Contraindications
The decision to proceed with surgical drainage is based on the presence of symptomatic disease and specific anatomical requirements.
Preoperative Investigations and Preparation
A multi-faceted approach is required to stabilize the patient and map the pancreatic anatomy before surgery.
Clinical and History: Evaluation of pain patterns, ethanol abuse history, and nutritional status. It is critical to establish the presence of narcotic use to plan for postoperative detoxification and weaning.
Laboratory Testing: Includes serum amylase/lipase, prealbumin, GGT, bilirubin, coagulation parameters, CA 19-9, and HbA1c.
Imaging: Mapping the ductal anatomy via CT, MRCP, or ERCP. Endoscopic ultrasound (EUS) may be used if indicated.
Surgical Optimization:
Maximize nutritional status and stabilize blood glucose (insulin).
Maximize exocrine status (enzyme replacement).
Perform bowel preparation and administer perioperative prophylactic antibiotics.
Surgical Procedure: The Modified Puestow
The procedure is a lateral pancreaticojejunostomy designed to provide extensive drainage from the tail to the head of the pancreas.
Stage 1: Exposure and Mobilization
The procedure begins with a generous Kocher maneuver to facilitate palpation of the pancreatic head. The lesser sac is entered through the gastrocolic omentum and transverse colon. Surgeons must identify and exclude the right gastroepiploic artery and vein located between the pancreatic head and the pylorus. Adhesions between the posterior stomach and anterior pancreas are transected to fully expose the gland.
Stage 2: Ductal Identification
The inferior border of the pancreatic body is mobilized while carefully avoiding the inferior mesenteric vein. The dissection extends toward the head to allow for bimanual examination. The main pancreatic duct is located by palpating the hard, fibrotic gland to find the "trough"—a soft area between the superior and inferior fibrotic borders.
Stage 3: Incision and Stone Removal
Once the duct is localized, an 18-gauge needle is used to aspirate pancreatic juice, confirming access. Electrocautery is then used to incise the anterior surface of the pancreas parallel to the needle. The duct is opened widely from the tail to the genu (bend) of the head.
The Head of the Pancreas: The incision must turn inferiorly at the genu to reach the ampulla, which increases the depth of the incision through the parenchyma.
The Frey Procedure Modification: If the pancreatic head is enlarged (> 4 cm), the tissue is excavated to an outer shell thickness of 1 cm.
Debridement: All encountered stones are removed using a Seurat clamp.
Stage 4: Roux-en-Y Jejunal Preparation
A jejunal limb is created approximately 15 cm distal to the ligament of Treitz. The jejunum is divided using a stapling device, and a window is created in the left transverse mesocolon. The distal end of the jejunum is brought through this window to be aligned with the pancreatic tail for a side-to-side anastomosis.
Stage 5: Pancreaticojejunostomy (The Anastomosis)
The anastomosis is performed using a single layer of 3-0 PDS absorbable sutures.
Posterior Suture Line: Created first, with smaller advances in the jejunum (3 mm) than in the pancreatic duct (6 mm) to account for the jejunum's tendency to dilate once opened.
Anterior Suture Line: Corner stitches are buried and transitioned from "outside-in" to "inside-out." Lembert sutures are placed halfway between the center and corners to ensure alignment.
Finalization: The jejunum is fixed to the mesocolon to obliterate internal hernia defects. A jejunojejunostomy is performed 40 cm distal to the pancreatic anastomosis. A 10 mm Jackson-Pratt drain is typically placed.
Postoperative Management and Complications
Clinical Monitoring
Immediate (24h): Strict monitoring for hemorrhage and serum glucose concentrations (even in previously non-diabetic patients).
Recovery: Progressive weaning from narcotics. Final success is often measured by the patient's ability to remain narcotic-free.
Potential Complications
Surgical Insights and Best Practices
Vascular Safety: Avoid accessing the duct directly over the junction of the superior mesenteric, portal, and splenic veins; deep incisions in this area can lead to serious hemorrhage.
Ultrasound Utility: If the duct is difficult to palpate, intraoperative ultrasonography should be used to locate the duct in the mid-body.
Juice Expression: Once an initial incision is made, the surgeon may safely massage the tail and proximal body to express pancreatic juice, confirming the duct's location.
Anastomotic Integrity: Proper size matching between the ductal incision and the jejunal incision is the most effective way to prevent pancreatic leaks.
