Every operation starts with a cut and ends when the incision is closed. And though the closing act that follows a complicated surgery may seem almost incidental, a surgeon's choice of needles, sutures or adhesives to do the job plays a big part in how well and how quickly the patient heals.
These days, there are more tools than ever at a surgeon's disposal. The choice of which one to use is as much art as science, often boiling down to a surgeon's personal preference, says Lee Nelson, a neurosurgeon with Boulder Neurosurgical Associates in Colorado. "Every surgeon probably uses 10 different types of sutures for different reasons," he adds. Flexibility, elasticity and strength of the materials are part of the calculation.
View our image gallery for a closer look at some of these tools of the trade.
The composition and thickness of a suture and needle depend on what the surgeon is closing. "Tissue near the spine is under a lot of tension, so you need a very strong suture," Nelson says, adding that he also uses a strong, thick suture when performing brain surgery. "But the fascia [or connective tissue] will heal itself and grow together, so you want a suture that's absorbable—generally lasting about three to four months." Closer to the skin, thinner needles and sutures are preferable because they leave fewer marks. (See a video explaining how surgeons chose the right needle for the job.)
Some sutures consist of a single strand of material that moves easily through tissue. Others are braids of multiple strands for increased strength and flexibility. "Monofilament sutures are less pliable than braided sutures but are easier to use in a continuous fashion because they don't cut the tissue as you pull them through," Nelson says. For this reason, he uses a monofilament suture when closing a patient's dura mater (the outermost of three layers of tissue surrounding the brain and spinal cord). "You want the [dura mater] to be watertight," Nelson adds. "The problem with the dura is that you create holes in it while you're suturing it, which could lead to a loss of spinal fluid. No one's been able to solve that problem."
Sutures are typically made from synthetic materials such as polymers. Natural materials, such as animal gut or silk, once dominated the market. But less than 10 percent of the sutures used in the U.S. today are made from gut, says Ed Dormier, vice president for new technology at Ethicon, a unit of Johnson & Johnson, in Somerville, N.J. (See a video of Dormier describing different types of sutures and their use.)
Surgeons also have the option of using staples made of plastic, stainless steel or titanium to tightly close incisions, either of internal organs or skin. Staples, the majority made by Johnson & Johnson's Ethicon Endo-Surgery, Inc., subsidiary in Cincinnati or Mansfield, Mass.–based Covidien, take less time to close a wound but are not as flexible as sutures, whose tension the surgeon controls. "I use staples to close cranial incisions behind the hairline," Nelson says, because they are quick and effective but tend to leave more visible scars. "I close all other visible incisions with suture."
In addition to sutures and staples, surgeons sometimes use adhesives on the skin to close wounds. Glue seals the skin, and patients treated with adhesive may not require a follow-up with their doctor. Over time the glue wears away and new skin cells replace it, says Upvan Narang, director of marketing for Ethicon's New Product Development division.
While adhesives have been used in surgery for the past decade, Ethicon believes the future of the technology is its Prineo Skin Closure System, available in Europe since 2007 and pending U.S. Food and Drug Administration approval.
The Prineo system uses a dispenser, like one for cellophane tape, to lay down mesh that a surgeon then covers with glue. The combination of mesh and adhesive is strong—capable of withstanding 150 millimeters of mercury of pressure.* That's about what a patient would experience by running, jumping or coughing, Narang says. (See a video of Narang demonstrating how Prineo works.)
Although neurosurgeon Nelson has used adhesives, he says he has been "underwhelmed" by their performance. "I haven't found anything that's better at closing a wound than a suture," he says. "I like for the wound to be able to breathe, so I don't like coating it with glue." Nelson has tried Ethicon's DermaBond as well as DuraSeal, made by Confluent Surgical, Inc., based in Waltham, Mass. (Covideon also makes a tissue adhesive called Indermil.)
Surgical adhesives can also be expensive. While Ethicon says the sale price of its products varies depending on the contract with the individual healthcare facility, Nelson estimates that the surgical glues he has used cost between $500 and $800 per five-cubic-centimeter dose. (A package of 10 sutures generally costs about $150, he adds.)
Given the variety of sutures, needles and adhesives available to surgeons, it is becoming increasingly difficult to impress them. Outside of developing some better way of sealing the dura mater following brain surgery, suture makers "have come just about as far as they can come," Nelson says. "If surgeons didn't upgrade their tools for the next 100 years, no one would bat an eyelash, for the most part."
*Correction (05/14/09): This article originally stated that the Prineo system is capable of withstanding 150 pounds per square inch of pressure.