Surgical staplers for mechanical suture anastomosis

The Aims of surgical stapling

1. Creating an adequate lumen

2. Preserving adequate tissue vascularization

3. Preventing tension of adapting tissues

4. Avoiding leakage and fistula formation

5. Providing good hemostasis

6. Ensuring mechanical reliability/uniformity of stapling devices  

Currently, staples are B-shaped . This special shape guarantees hemostasis and enables sufficient blood supply to the tissue edges. This shape supports wound healing and prevents necrosis. Absorbable and nonabsorbable staples are available. There are multiple different sizes of staplers according to tissue thickness and whether a hollow viscus or a vascular vessel is being stapled. Currently, nonabsorbable staples are made of titanium, which have the following key benefits:

• Minimal artifacts in computed tomography

• Not magnetic and thus cause only minimal distortions in magnetic resonance imaging.

• High resistance and lighter, than stainless steel

• Corrosion resistant

Biocompatible; can be safely used in patients who suffer from chromate-nickel allergy. Absorbable staples are made of a copolymer (lactomer), break down into glycol and lactic acid, and are absorbed through hydrolysis. The copolymer still shows adequate tear resistance in tissue 14 days after deployment. Their absorption starts after 4 weeks and is completed after 180 days. Linear staplers are predominantly used to close the ends of a hollow organ or vessel. They are claimed to give easier access to narrow anatomic sites such as the pelvis. For such applications, linear staplers with articulated heads and flexible shafts have been developed. These staplers usually apply two lines of staples that are staggered to maximize local blood supply. Vascular linear staplers apply three staggered lines of staples to achieve tight closure of the vessel. The staple height is either fixed or, with some brands of stapler, can be “adjusted” during the application. For most applications, the use of a fixed staple height is preferred. Because linear staplers are mainly used to close open organs, they do not include a cutting device. The length of the stapler lines varies between 30 mm and 90 mm, while the height of individual staples varies from 2.5 mm to 4.8 mm, depending on the tissue to be stapled (e.g., vascular staples = 2.5mm; staples for intestinal tissue = 3.5mm; for stomach or thicker tissues = 4.8mm). You can use different sizes of cartridges and staples. It can be used with just one hand. It can be recharged up to 7 times. Cartridges are white for vascular tissue, blue for standard tissue and green for thick tissue. Linear Cutter Stapler These staplers are basically linear staplers with an integrated cutting device. Four or six staggered lines of staples (two or three “rows”) are applied, and the tissue between the two inner staple lines is transected. The main indications are transecting and stapling closed both ends of a hollow organ (e.g., bowel, bronchus) or vascular structure. In addition, because of the two separate rows of staples, side-to-side anastomoses can be created. The staple height is fixed and must be chosen before using the instrument in accordance to the type of tissue. Different staple sizes and wire diameters are available in preloaded, single-use cartridges. The length of the staple lines varies between 55mm and 100mm for open surgery. Specially designed linear cutters have been developed for minimally invasive surgery . Articulated heads are often used to overcome angulations related to the trocar positioning. They are used to close partially or totally hollow organs. Depending on the purpose, different stapler cartridges ranging from 30–90 mm of length are available, as well as staples ranging in height from 3.5–4.8 mm before being fired and assuming the B shape. The Endo GIA Ultra Universal stapler delivers increased versatility.

• Articulation: Up to 45 degrees

• One-handed Grasping Mechanism

• Compatibility: Endo GIA Ultra Universal staplers can be used with Endo GIATM Reloads with Tri-StapleTM Technology, Endo GIA Straight and Endo GIATM RoticulatorTM reloads  

Tri-Staple technology reloads with its stepped cartridge face, delivers graduated compression, optimizing interaction between the tissue and stapler because it:

• Generates less stress on tissue during compression and clamping

• May allow greater perfusion into the staple line

• Provides superior performance in variable thicknesses

• The improved design of the stronger fixed anvil and I-beam reload results in improved staple line strength, leak resistance and hemostasis when compared to the universal reloads.

Simpler Selection: The broader indicated tissue range allows one size reload to work over a broader range of tissue thickness. Eliminates 15mm Trocar: Both the tan and purple reload use a 12mm port Tri-Staple Tan Reload: Incorporates 2.0, 2.5 and 3.0mm staples and is designed to accommodate a tissue thickness range of 0.88mm–1.8mm. Tri-Staple Purple Reload: Incorporates 3.0, 3.5 and 4.0mm staples and is designed to accommodate a tissue thickness range of 1.5mm–2.25mm. Tri-Staple Black Reload: Incorporates 4.0, 4.5 and 5.0mm staples and is designed to accommodate a tissue thickness range of 2.25mm–3.0mm. Endo GIA Radial Reload allows surgeons uncompromised access and visibility in the deep pelvis. The Radial Reload incorporates a spring loaded tissue retainer affixed to the distal tip of the cartridge. This feature is designed to assist in guiding the device into place without entrapment of excessive tissue. Compatible with Tri-Staple technology delivers 6 rows of variable height staples and graduated compression. Circular stapling devices fire two staggered circular lines of staples. After “firing” the stapler, an integrated circular scalpel resects overlaying tissue as “rings” or “donuts” of tissue and creates a circular anastomosis. Circular stapling devices are applied in general surgery as well as in thoracic and colorectal surgery. They are used for end-to-end anastomosis after bowel resection or in esophagogastric surgery. Using circular staplers, a “tobacco pouch seam” or “purse string suture” is mandatory to approximate the intestinal lumen close to the anvil or device. Diameters between 21–34 mm are available, whereas staple length is usually 5.5 mm in size, but can also vary with the thickness of the tissues. There is a device that can be inserted orally to perform anastomosis with circular staplers. The anvil assembly is mounted on a 90cm long PVC delivery tube and is secured to the tube with a suture. When used with the DST Series™ EEA™ XL 21 or 25 mm stapler, a circular, double staggered row of titanium staples is placed. Immediately after staple formation, the stapler knife blade resects the excess tissue, creating a circular anastomosis. The diameter of the staple line is 21 mm or 25 mm, depending on the device selected. The Signia stapler measures the force to clamp and  fire the stapler. This is how it works: Three zones were developed based on force measurements in variable tissue thicknesses Firing speeds were programmed for each zone to optimize staple formation. Higher force measurements indicate thicker tissues, more challenging tissue conditions, additional material in the jaws, or maximum device articulation. Approved Indications for Use of Staplers in Gastrointestinal Surgery Esophagus - Resection of or incorporation of a Zenker diverticulum, Gastric tube formation, Intrathoracic esophagogastrostomy. Small bowel - Resection of Meckel diverticulum or the appendix. Stomach - Closure of the stomach, Closure of the duodenal stump, intraabdominal and intramediastinal esophagojejunostomy, formation of a jejunum or ileal pouch. Colon/rectum - Deep colorectal, coloanal, and ileoanal anastomosis partly in “double-stapling, technique”. Formation of an ileal pouch, Formation of a colonic pouch. Tips After firing the stapler, wait 20–30 seconds to allow the tissue to be squeezed together whic  helps to prevent bleeding from the stapler lines. The anastomosis should never be under tension. Before resecting tissue using a mechanical stapler, make sure to have an adequate blood supply of the remaining tissue. Check every anastomosis for leak-tightness.