Intestinal Staplers - Complete Surgical Reference

Historical Background

Basic Principle

1. A two-piece system (two jaws or a detachable anvil) clamps the tissue between them
2. One jaw carries a reloadable staple cartridge; the opposing jaw (anvil) shapes the staple
3. On firing, an I-beam or sliding driver mechanism pushes rows of staples through the tissue
4. The staple legs pass through the tissue and bend against the anvil, deforming into a "B" shape - this is the key to hemostatic closure while still allowing tissue perfusion

Types of Intestinal Staplers

1. Linear Cutting Stapler (GIA - Gastrointestinal Anastomosis)

• White (2.5 mm open height, closed ~1 mm): vascular tissue, mesentery
• Blue (3.8 mm): standard for small bowel and colon
• Green (4.8 mm): thick tissue (stomach, thickened bowel)

2. Linear Non-Cutting Stapler (TA - Thoracoabdominal / Proximate TL)

3. Circular (EEA - End-to-End Anastomosis) Stapler

4. Curved Cutting Stapler (Contour Stapler, Ethicon)

Diagrams and Images

Techniques of Application

A. Side-to-Side (Functional End-to-End) Anastomosis - GIA Stapler

1. Resect the bowel segment using GIA stapler to divide proximal and distal margins
2. Create an enterotomy on the two stapled ends - either by cutting a corner of the staple line, or making a small stab on the antimesenteric side ~1 cm from the staple line
3. Insert one jaw of the GIA stapler into each lumen; align the two bowel limbs along the antimesenteric border
4. Confirm no mesentery is trapped in the jaws
5. Close the jaws and fire - the driver is pushed to the end of its track and back to deploy staples and divide tissue
6. Open and remove the stapler; inspect the internal staple line for hemostasis
7. Place a crotch stitch at the apex of the common channel to reduce tension at this high-stress point
8. Approximate the open enterotomy with Allis clamps, offsetting the two staple lines (avoids a single thick suture line)
9. Close the common enterotomy with a second GIA load or a TA stapler fired below the clamps
10. Optionally reinforce with interrupted Lembert sutures; close mesentery per preference

B. End-to-End (Double-Staple) Colorectal Anastomosis - EEA Stapler

1. Resect the bowel; fire a TA stapler across the rectum (distal margin)
2. Open the proximal colon end; place the EEA anvil into it and secure with a full-thickness purse-string suture (hand-sewn or using a purse-string device)
3. Insert the EEA handle/body transanally through the rectum and advance to the top of the rectal stump
4. Turn the knob to "open" position - the center pin telescopes out through or beside the TA staple line of the rectal stump
5. Mate the pin to the anvil shaft
6. Turn the knob to "closed" position - this draws the two ends of bowel together; confirm the tissue indicator is in the green (optimal compression) zone
7. Ensure no other bowel loops or tissue are caught in the mechanism
8. Fire the instrument - this simultaneously deploys two circular rows of staples and cuts an inner ring of tissue
9. Withdraw the device; inspect the two "donuts" (circular tissue specimens) which should both be complete - incomplete donuts indicate a defective anastomosis
10. Leak test: rigid or flexible sigmoidoscopy with air/saline insufflation to confirm airtight seal
11. Consider diverting loop ileostomy if: positive leak test, prior radiation, malnutrition, steroid use, very low pelvic anastomosis, or technically difficult case

C. Bowel Resection and Closure (TA Stapler)

1. Place the TA stapler across the bowel at the desired resection point, ensuring the pin at the distal end is engaged
2. Fire the stapler to close the bowel
3. Divide the bowel manually (scalpel) just beyond the staple line
4. The staple line is typically 30-90 mm in length; multiple applications may be needed for larger structures

Indications

Complications

Anastomotic Leak

• Inadequate blood supply to the anastomosis
• Tension on the anastomosis
• Incomplete donuts after EEA firing (defective staple line)
• Misfired or partially fired stapler
• Wrong tissue thickness for cartridge height selected
• Infection, malnutrition, immunosuppression, radiation

Staple Line Bleeding

• Can be intraluminal (causing GI bleeding) or extraluminal (intra-abdominal hematoma)
• Risk increases if wrong staple height used for tissue thickness (too small = incomplete closure; too large = inadequate compression)
• Treatment: oversewing, clips, fibrin glue application to the staple line

Anastomotic Stricture

• Circular stapler anastomoses are prone to stricture, especially with smaller diameter devices
• Related to ischemia, excessive fibrosis, or oversewing
• The resultant inner lumen of an EEA anastomosis is already up to 10 mm smaller than device diameter

Misfire / Device Malfunction

• Failure to deploy all staples (incomplete staple line)
• Knife failure (staples fired but tissue not cut)
• Cartridge fired without tissue (inadvertent firing)
• Incomplete donut retrieval

Tissue Inclusion Errors

• Mesentery caught in the staple line (GIA) - compromises bowel viability
• Adjacent bowel loops caught in EEA closure mechanism
• Vaginal wall or ureter incorporated (rare but serious)

Bowel Obstruction

• Early: due to hematoma, edema at anastomosis
• Late: anastomotic stricture, adhesions around the staple line

Staple Line Reinforcement (SLR)

• Absorbable synthetic buttress (glycolide or trimethylene carbonate copolymer matrices)
• Biologic buttress (porcine small intestinal submucosa)
• Oversewing the staple line with absorbable sutures
• Fibrin glue / tissue sealants

Key Technical Pearls

• Always select the appropriate staple height for the tissue thickness - this is one of the most common sources of error
• For the GIA: offset the staple lines when closing the common enterotomy to avoid a bulk junction point
• For the EEA: both donuts must be complete; an incomplete donut mandates direct inspection and reinforcement sutures
• Always perform an intraoperative leak test (air/saline via flexible or rigid scope) for distal colorectal anastomoses
• Laparoscopic/robotic versions (Endo-GIA, Echelon, articulating models) use identical principles but are fired through trocars; articulation assists with deep pelvic or complex angle applications
• Powered staplers are now available and may improve consistency of the firing mechanism
• Never reuse a single-use cartridge; ensure the safety mechanism is off before firing

Comparison: Stapled vs. Hand-Sewn Anastomosis

• Hinman's Atlas of Urologic Surgery, Chapter: Intestinal Division and Anastomosis (pp. 55-58) - Cone MM, Geiger TM
• Sabiston Textbook of Surgery (21st ed.), Chapter: Surgical Staplers
• Fischer's Mastery of Surgery (8th ed.), Chapters: Surgical Staplers; Stapler Buttress Materials; Gastrointestinal Leak