GMD has been committed to creating a world-class manufacturing facility capable of delivering superior quality Sterile Medical Disposables to the markets. The high quality materials we use to manufacture products – from sutures to needles to packaging – ensure superior consistent performance.
Surgical Suture Manufacturing| Raw material, Design and Manufacturing process
A surgical suture is used to close the edge of a wound or incision and to heal damaged tissue. There are several types of sutures, with various types of appropriate for different uses. Sutures can be classified into two major classes: absorbable and none-absorbable. An absorbable suture decomposes in the body. It degrades as a wound or incision heals. A non-absorbable suture resists the body’s attempt to dissolve it. Non-absorbable sutures may be removed by a surgeon after a surface incision has healed.
Sutures are made from both man-made and natural materials. Silk, linen, and catgut, which is actually a cow or sheep’s dried and handled intestine, are natural suture products. Synthetic sutures are made from several textiles specially designed for medical use such as nylon or polyester.
Natural sutures are made of catgut or reconstituted collagen, or from cotton, silk, or linen. Synthetic absorbable sutures may consist of polyglycolic acid, a copolymer of glycolide-lactide, or polydioxanone, a glycolide and trimethylene carbonate copolymer.
Synthetic nonabsorbable sutures may be made of polypropylene, polyester, polyethylene terephthalate, polybutylene terephthalate, polyamide, different proprietary nylons, or Goretex. Some sutures are made out of stainless steel as well.
Sutures are designed to serve several different needs. For instance, sutures for abdominal surgery are different from sutures used in cataract surgery. Since no one type of suture is suitable for any treatment, sutures with various qualities have been developed by surgeons and medical designers. One may be more absorbable, but less flexible, while another may be extremely solid, but maybe very hard to knot. This offers many options for surgeons. Many considerations have to be taken into consideration by designers of a new suture. Not only along the length of the suture but at the knot, the rate at which the suture degrades is significant. It is necessary for certain sutures to be elastic so that they stretch and not break. Others need a close grip. To test and research sutures, manufacturers of sutures use specially built devices. New suture patterns, such as soaking them in different solutions and experimenting on animals.
The manufacturing process
- The first step in the manufacturing of sutures is to generate the raw polymer. Staff test the chemicals that make a chemical reactor out of the polymer. The chemicals are mixed (polymerized) in the reactor, pushed through a die, and discharged as small pellets.
- Next, employees empty the pellets into an extrusion system. There is a nozzle on the extruder, which looks like a showerhead, pierced with several tiny holes. The machine melts the polymer, and through the tiny gaps, the liquid flows, creating several individual filaments.
- The filaments are stretched between two rollers after extrusion. The filaments stretch to their original length as much as five times.
- Some sutures are produced as monofilaments. Others are braided or twisted. To braid the suture, the extruded monofilament is wound onto bobbins, and the bobbins are loaded onto an automatic braiding machine.
- After braiding, the suture undergoes several stages of secondary processing. Non-braided sutures will also go through these steps after extrusion and initial stretching.
- Next, workers pass the suture through an annealing oven. The annealing oven subjects the suture to high heat and tension, which actually orders the crystalline structure of the polymer fiber into a long chain. This step may take several minutes or several hours, depending on the type of suture being made.
- After annealing, the suture may be coated. The coating material varies depending on what the suture is made of. The suture passes through a bath of coating material, which may be in solution or may be in a thick, paste-like state called a slurry.
- All the major manufacturing steps at the processing plant are complete at this point. Now the quality assurance workers test the batch of suture for various qualities. These workers make sure the suture conforms to the proper diameter, length, and strength.
- The surgical needles are made at another plant, and also shipped to the finishing plant. The needles are made of fine steel wire and drilled lengthwise. Workers at the finishing plant cut the suture into standard lengths.
- Next, the suture and attached needle are inserted into a foil packet and sterilized. Sterilization differs according to the suture material. Some sutures are sterilized with gamma radiation. In this case, the sutures are packaged completely. The whole package, typically a sealed foil pack inside a cardboard box, is set on a conveyor belt. The sealed package passes under pencil-shaped lenses emitting gamma radiation. This kills all microbes.