Surgical staple

34 surgical staples closing scalp following craniotomy

X-ray of surgical staples

Surgical staples are specialized staples used in surgery in place of sutures to close skin wounds, connect or remove parts of the bowels or lungs. A more recent development, from the 1990s, uses clips instead of staples for some applications; this does not require the staple to penetrate.

Stapling is much faster than suturing by hand, and also more accurate and consistent. Staples are primarily used in bowel and lung surgery, because staple lines are more consistent and therefore less likely to leak blood, air or bowel contents. Still, several randomized controlled trials have shown no significant difference in bowel leakage after anastomoses performed either manually with suture by experienced surgeons, or after mechanical anastomoses with staples. In skin closure, dermal adhesives (skin glues) are also an increasingly common alternative.

History

Staplers were originally developed to address the perceived problem of patency (security against stenosis or occlusion of the lumen) and tightness (security against leaks of blood or bowel contents) as well as easiness and quickness in performing the anastomosis. Leaks from poor suturing of bowel anastomoses was at that time a significant cause of post-surgical mortality. More recent studies have shown that with current suturing techniques there is no significant difference in outcome between hand sutured and mechanical anastomoses, but mechanical anastomoses are significantly quicker to perform.

The technique was pioneered by a Hungarian surgeon, Humor Hultl, known as the "father of surgical stapling". Hultl's prototype stapler of 1908 weighed eight pounds (3.6 kg), and required two hours to assemble and load. Many hours were spent trying to achieve a consistent staple line and reliably patent anastomoses.

The early instruments, by developers including Hultl, von Petz, Friedrich and Nakayama, were complex and cumbersome to use. The technology was refined in the 1950s in the Soviet Union, allowing for the first commercially produced re-usable stapling devices for creation of bowel and vascular anastomoses. Mark M. Ravitch, brought a sample of stapling device after attending a surgical conference in USSR, and introduced it to entrepreneur Leon C. Hirsch, who founded the United States Surgical Corporation in 1964 to manufacture surgical staplers under its Auto Suture brand. Until the late 1970s USSC had the market essentially to itself, but in 1977 Johnson & Johnson's Ethicon brand entered the market and today both are widely used, along with competitors from the Far East. USSC was bought by Tyco Healthcare in 1998, which became Covidien on June 29, 2007.

Safety and patency of mechanical (stapled) bowel anastomoses has been widely studied. It is generally the case in such studies that sutured anastomoses are either comparable or less prone to leakage. It is possible that this is the result of recent advances in suture technology, along with increasingly risk-conscious surgical practice. Certainly modern synthetic sutures are more predictable and less prone to infection than catgut, silk and linen, which were the main suture materials used up to the 1990s.

One key feature of intestinal staplers is that the edges of the stapler act as a haemostat, compressing the edges of the wound and closing blood vessels during the stapling process.

Types and applications

Laparoscopic cholecystectomy.

Close-up demonstration of a surgical skin stapler.

The first commercial staplers were made of stainless steel with titanium staples loaded into reloadable staple cartridges.

Modern surgical staplers are either disposable and made of plastic, or reusable and made of stainless steel. Both types are generally loaded using disposable cartridges.

The staple line may be straight, curved or circular. Circular staplers are used for end-to-end anastomosis after bowel resection or, somewhat more controversially, in esophagogastric surgery. The instruments may be used in either open or laparoscopic surgery, different instruments are used for each application. Laparoscopic staplers are longer, thinner, and may be articulated to allow for access from a restricted number of trocar ports.

Some staplers incorporate a knife, to complete excision and anastomosis in a single operation. Staplers are used to close both internal and skin wounds. Skin staples are usually applied using a disposable stapler, and removed with a specialized staple remover. Staplers are also used in vertical banded gastroplasty surgery (popularly known as "stomach stapling").

Vascular stapler for reducing warm ischemia in organ transplantation. With this model each stapler end can be mounted on donor and recipient by independent surgical teams without care for reciprocal orientation, being the maximal possible vascular axis torsion ≤30°. Activating guide-wire is connected just immediately before firing (video)

While devices for circular end-to-end anastomosis of digestive tract are widely used, in spite of intensive research circular staplers for vascular anastomosis never had yet significant impact on standard hand (Carrel) suture technique. Apart from the different modality of coupling of vascular (everted) in respect to digestive (inverted) stumps, the main basic reason could be that, particularly for small vessels, the manuality and precision required just for positioning on vascular stumps and actioning any device cannot be significantly inferior to that required to carry out the standard hand suture, then making of little utility the use of any device. An exception to that however could be organ transplantation where these two phases, i.e.device positioning at the vascular stumps and device actioning, can be carried out in different time, by different surgical team, in safe conditions when the time required does not influence donor organ preservation, i.e. at the back table in cold ischemia condition for the donor organ and after native organ removal in the recipient. This is finalized to make as brief as possible the donor organ dangerous warm ischemia phase that can be contained in the couple of minutes or less necessary just to connect the device's ends and actioning the stapler.

Although most surgical staples are made of titanium, stainless steel is more often used in some skin staples and clips. Titanium produces less reaction with the immune system and, being non-ferrous, does not interfere significantly with MRI scanners, although some imaging artifacts may result. Synthetic absorbable (bioabsorbable) staples are also now becoming available, based on polyglycolic acid, as with many synthetic absorbable sutures.

Titanium staples are not suspected of causing nickel reactions because nickel is rarely if ever used in titanium alloys.

Removal of skin staples

Where skin staples are used to seal a skin wound it will be necessary to remove the staples after an appropriate healing period, usually between 5 and 10 days, depending on the location of the wound and other factors. The skin staple remover is a small manual device which consists of a shoe or plate that is sufficiently narrow and thin to insert under the skin staple. The active part is a small blade that when hand-pressure is exerted it pushes down on the staple and pushes it through a slot in the shoe and deforms the staple into an 'M' shape to facilitate it removal, although in an emergency it is possible to remove them with a pair of artery forceps. Skin staple removers are manufactured in many shapes and forms, some disposable and some reusable.

See also

• Instruments used in general surgery