What is an internal J (jejunal) pouch?

Internal J Pouch: A Surgical Reservoir for Gastrointestinal Continuity

An internal J pouch is a surgically created reservoir formed from intestinal tissue, most commonly from the ileum, that is shaped like the letter "J" to create a new storage area for stool following removal of diseased portions of the gastrointestinal tract.

Types and Applications of J Pouches

Ileal J Pouch (Most Common)

• Used primarily after total proctocolectomy in patients with ulcerative colitis or familial adenomatous polyposis
• Known as ileal pouch-anal anastomosis (IPAA) or J-pouch
• Creates a new rectal reservoir from ileum to maintain bowel continuity and avoid permanent ileostomy 1, 2
• Constructed by folding a segment of terminal ileum back on itself in a "J" configuration
• Typically 15-20 cm in length (combined limbs)

Colonic J Pouch

• Used after low anterior resection for rectal cancer
• Improves functional outcomes compared to straight coloanal anastomosis
• Reduces stool frequency (2.5 vs 4.7 stools/day) and improves continence 3, 4
• Typically 5-6 cm in length

Jejunal J Pouch

• Used for reconstruction after total gastrectomy (Hunt-Lawrence technique)
• Creates a reservoir to replace the stomach's storage function
• Can improve nutritional outcomes and reduce postgastrectomy symptoms 5, 6
• Constructed intracorporeally during laparoscopic or robotic procedures

Surgical Construction Technique

For ileal J pouch (IPAA):

1. Total proctocolectomy is performed first
2. Terminal ileum is folded back on itself in "J" configuration
3. The limbs are stapled together to create the pouch
4. The pouch is anastomosed to the anal canal (pouch-anal anastomosis)
5. A temporary diverting ileostomy is typically created 2

Functional Benefits

The J pouch configuration offers several advantages:

• Creates a reservoir to store stool/food
• Decreases stool frequency
• Improves continence for gas and liquids
• Reduces urgency
• Allows for more normal bowel function

Research shows the J pouch configuration is superior to straight anastomosis in terms of:

• Lower stool frequency
• Better continence
• Improved quality of life 3, 7

Clinical Considerations

Patient Selection

• Best results in ulcerative colitis patients without perianal or small bowel disease
• Can be considered in carefully selected Crohn's disease patients, though with higher failure rates 1
• Used in rectal cancer patients requiring low anterior resection

Complications

• Pouchitis (inflammation of the pouch) occurs in approximately 20% of patients within 1 year and 50% within 10 years 1
• Pouch failure rate is approximately 15% lifetime 2
• Other complications include strictures, fistulas, and small bowel obstruction

Monitoring

• Endoscopy and imaging (MRI, CT) are used to evaluate pouch-related complications
• CT enterography has 90% sensitivity for diagnosing pouchitis when more than 2 signs of inflammation are present 1

Why J Configuration is Preferred

The J pouch is the most commonly used configuration (compared to S, W, or H pouches) because of:

• Simplicity of construction
• Reliability
• Limited use of intestine
• Good functional outcomes 1, 2

The functional advantage of J pouches appears to be related not just to increased reservoir capacity but also to decreased motility and better retention of liquid content 3, 7.