In spite of the constant strides being made in modern surgery, poor wound-healing and the development of infections continue to bring about complications for patients.

With an estimated 27 million surgical procedures taking place each year in the US, and a 2-5% rate of surgical site infections (SSIs), approximately 300,000-500,000 such infections are thought to occur each year. They are believed to increase the risk of death by a factor of two to 11, with 77% of these deaths attributed directly to the SSI.

SSIs can also increase hospital stays 20-fold and cost increases five-fold, resulting in a net loss of reimbursement for hospitals.

At present, hospitalisation for SSIs creates direct costs that can be estimated to be in excess of $1.5 billion a year. That’s not even taking into account the emotional impact on patients and their families.

Given that almost all post-operative wound infections develop along suture lines, or in their immediate proximity, the role carried out by suture material in the development of wound infections remains under close scrutiny among surgeons.

The main area of debate concerns the idea that bacteria not only contaminate the tissue in the surgical wound but also the suture itself, which can, in turn, become a breeding ground for wound infections.

The state of play

To prevent contamination, suture materials are currently coated in triclosan, which has antiseptic properties. Since the 1960s, triclosan has been used in underarm deodorants and deodorant soaps in the US, and was first introduced into the healthcare industry in the form of a surgical scrub.

Over the past two decades, its use has grown rapidly in personal care products including soap, cosmetics and toothpaste, as well as household products such as odour-fighting socks, germ-resistant sponges, kitchenware and bedding.

"The susceptibility of the most common device-related pathogens, combined with innately low levels of toxicity, makes triclosan a preferable choice for use in antimicrobial sutures."

The susceptibility of the most common device-related pathogens, combined with innately low levels of toxicity, makes triclosan a preferable choice for use in the clinical setting for antimicrobial sutures. This has been demonstrated by several industry investigations examining the relationship of suture construction and chemical composition – as this directly relates to bacterial attachment and surgical infection.

A recent review of triclosan indicated little or no risk of resistance, carcinogenic potential, genotoxicity or skin sensitisation. Pharmacokinetic studies have also demonstrated that triclosan is rapidly absorbed, well distributed, metabolised in the liver and excreted by the kidneys, and bears no association with antibiotic resistance or susceptibility of bacteria isolated in the community.

Yet, as triclosan can be absorbed into the body, there are still some concerns over possible adverse health effects. Another downside to triclosan is that, although it slows down the growth of bacteria, it does not actually kill those already present.

Other studies have also shown that triclosan enhances the production of chloroform when in contact with chlorine, which is classified by the Environmental Protection Agency (EPA) as a probable human carcinogen.

At present, Ethicon is the only manufacturer of commercially available antimicrobial sutures. Its products, which are manufactured by adding triclosan to the original suture, were approved for clinical use by the FDA in 2002.

Yet, doubts still remain over efficacy, and there have been calls for the FDA to re-evaluate their use.

Pep talk

In August 2012, in response to "an urgent need for better antibacterial coatings on surgical sutures", scientists from the American Chemical Society reported the discovery of a new coating claimed to be almost a thousand times more effective than the most widely used commercial coating.

Working with PAMBM, a new amphiphilic polymer substance derived from naturally occurring antimicrobial peptides and able to kill a wide range of bacteria, scientists claimed that, because of the way it works, PAMBM has a very low chance of causing bacterial resistance and therefore of leading to the emergence of superbugs.

The report also described laboratory tests in which PAMBM greatly reduced the amount of bacteria when compared with triclosan. In a head-to-head test with triclosan-coated sutures, those coated with PAMBM were much more effective against bacteria.

"As bacterial resistance to current agents continues to increase, and with resistance to triclosan now documented, the discovery of new antimicrobial agents that remain active in biomedical device coatings is essential," said researchers at the time.

On trial

However, things have gone quiet on the PAMBM front, which only goes to show the tricky position the field of antibacterial sutures finds itself in. In spite of their albeit limited commercial availability, question marks still linger over their effectiveness.

At this juncture, it is perhaps necessary to quickly contrast the clinical effectiveness of antibacterial sutures with their adverse effects.In a nutshell, it is as follows: surgical-wound infection increases costs, yet the cost-effectiveness of antibacterial-coated sutures is uncertain.

This would suggest that higher-quality research is needed, but the number of large clinical trials investigating new prevention techniques is still small. Likewise, there is a paucity of literature on antibacterial sutures, which may be due to the difficulties of standardising patient cohorts or as a result of large trials being so time and cost-intensive.

IT-based clinical pathways may pave the way ahead by providing a tool able to generate scientific data from large study cohorts with minimal cost. Looking forward, a greater number of innovative technologies and devices will be needed to prevent wound infections – especially for patients with an increased risk of SSIs.