Stitches or Sutures: Wound Closure Today and in History
From ancient to modern times, healers have joined the separated edges of wounds together by sewing. It’s a good technique to close spaces, reduce infection, speed healing and minimize scarring. Stitches are still the most common method of repairing large and gaping wounds today, but newer techniques are being used as well. These methods include sealing injured areas with medical tape, adhesive and staples. The use of lasers to close wounds may be common in the near future.
As long ago as the Upper Paleolithic period, people sewed. They punched holes in animal hides with needles made from bone, antler, horn or ivory and then drew thread through the holes. It’s unknown when people first realized that just as pieces of animal skin can be sewn together, so can pieces of human skin.
Ancient Greeks, Romans and Egyptians - and perhaps even earlier cultures - knew about the value of suturing (stitching) wounds. The earliest written records describing the use of medical sutures come from Ancient Egypt, where physicians used stitches to close injuries, incisions and mummies, but the medical uses of stitches may have begun long before this time.
Early Needles and Threads
The oldest known eyed sewing needle is about 25,000 years old and was discovered in France. It’s made of bone. Even older implements that may have been sewing needles have been found. The earliest threads were probably plant fibers like cotton, flax and hemp, or animal fibers such as hair, muscle strips, tendons, nerves, arteries, strips of gut and silk.
The eyed needle is a dual-purpose device and was a very useful invention in human history. Using one end of a needle to pierce holes in two pieces of material and the other end, or eye, to pull a thread through the holes to join the materials together is a simple but effective technique. It's helpful for both repairing damage and making new items.
As time progressed, metal needles replaced bone ones. The earliest known iron sewing needles were discovered in Germany and date from the third century B.C. Today both metal needles and needles made of synthetic materials are available.
Although eyed needles are used in medicine today, a newer type in which the thread is fused with the needle is often preferred.
Suturing Solutions in Nature
Nature has provided people with suturing materials in the past and sometimes still does in the present. Large ants are used as suturing agents in some cultures. An ant is provoked so that it bites the edges of a wound, pulling them together. The insect’s body is then removed, leaving the head grasping the broken ends of the skin and acting as a clamp that sutures the injury. Another natural technique is to use plant thorns as needles and plant fibers as threads.
Needles and suture materials from nature may be useful in an emergency, but they are more likely to produce infected wounds than modern suturing techniques performed by medical professionals. Doctors know how to clean wounds properly and stop bleeding if it's still occurring when a wound is about to be stitched. They use sterilized needles and thread and are experienced in minimizing scar formation or scar visibility.
Using an Ant to Seal a Wound
Modern Suturing Needles
Modern suturing needles come in a range of body and tip shapes, enabling a doctor to choose the best implement for the job at hand. A variety of threads and stitch styles can be used to create the sutures.
Suturing may be performed with an eyed needle and separate thread that needs to be drawn through the eye before use. It may also be done with an eyeless needle called a swaged or atraumatic needle, which is supplied by the manufacturer with the thread pre-attached. Swaged needles are "atraumatic" because they generally have a gentler effect on body tissue. The suturing needle is held in a needle holder, which the sewer moves to guide the needle and its thread as he or she sutures a wound.
Interrupted Sutures on a Banana (for Veterinary Students)
In interrupted sutures, the stitches aren't connected. Each stitch is individually placed and tied. In continuous sutures, one piece of thread is used to create all of the stitches. The thread isn't cut and tied until the last stitch has been created.
A wide range of materials are available to make the threads of today’s sutures, giving a doctor many options. Sutures are classified as absorbable or non-absorbable. Absorbable sutures, also known as dissolving stitches, are eventually broken down by the body, while non-absorbable sutures need to be removed once a wound has healed and the broken skin pieces have formed a permanent bond.
Absorbable sutures are often made of synthetic polymers produced from substances such as polyglycolic acid. In some countries absorbable sutures are also made of gut material obtained from cow or sheep intestine. This material is sometimes called "catgut", but it isn't made from cat organs. Two varieties of catgut are plain catgut and chromic catgut. Chromic catgut has had chromium salts added so that it lasts longer in the body. Non-absorbable sutures are made from silk, nylon, polypropylene, polyester or other artificial materials.
Continuous Sutures (for Veterinary Students)
Although interrupted sutures take longer to create than continuous ones, they are more popular. If one interrupted stitch breaks, the others may be able to keep the wound closed. This is less likely in continuous sutures.
Closing Wounds with Butterfly Stitches, Adhesives and Staples
Butterfly stitches are narrow strips of adhesive tape which are used instead of true stitches to seal small wounds. They are placed across a wound to pull the broken edges of the skin together.
Skin adhesive is sometimes called skin glue or liquid stitches. It's generally used to treat minor wounds with straight skin edges. As the liquid adhesive dries it pulls the edges of the wound together. The adhesive is waterproof (but it does need to be gently patted dry after a bath or shower) and eventually falls off.
Surgical staples are also used to hold the edges of broken skin together. In addition, they’re sometimes used to hold broken parts of a lung, intestine or other organ together because staples may allow less air or body fluids to escape than thread sutures do (although thread sutures that are correctly placed are often considered to be just as effective as staples).
Staples are quicker to apply than regular sutures and can be placed accurately and evenly. The staples are made of a titanium alloy, stainless steel or a plastic. There are even absorbable staples made from polyglycolic acid.
Healing Wounds with Lasers
Laser Tissue Welding
Sealing wounds with a laser is an exciting new treatment that offers several advantages over other wound closure methods. Laser treatment repairs damage rapidly and produces a watertight seal. It shortens the time needed for surgery as well as the wound healing time. The technical name for the process is photochemical tissue bonding or laser-assisted nanosuturing.
Laser sutures have been tested on animal tissue and in humans. Researchers at the Massachusetts General Hospital report that when the skin on each side of an open wound is coated with a dye called Rose Bengal, green laser light will seal the wound. The light activates the dye and and causes it to bind the collagen in the separated pieces of skin together. Unlike the case with the first laser suture experiments, the skin isn't heated or burned.
The bond between the skin sections is continuous and lacks the gaps that occur between conventional sutures. This may decrease the chance of an infection developing. In addition, the researchers found that the healed wound had an improved appearance and that the patients who received the laser treatment experienced less inflammation than with the usual treatments.
Rose Bengal is a stain that is sometimes used by ophthalmologists to make parts of the eye stand out. It's being investigated for other medical uses besides eye examinations and laser welding.
Guiding Light into Deep Tissues
A potential problem with creating laser sutures is that the light doesn't penetrate deeply into tissues. This has limited the use of lasers in closing wounds. Recently, however, a group of researchers reported that they had created a bioabsorbable, comb-shaped waveguide that sends light into deep wounds. A bioabsorbable device gradually breaks down in the body, so it doesn't need to be removed once it's done its job.
The scientists found that when their device was used, light was able to travel ten times deeper into pig skin than it could in regular photochemical tissue bonding. Furthermore, the light was able to seal the wound throughout the thickness of the tissue.
Lasers and a Protein Glue For Closing Wounds
Researchers at Arizona State University have created a "glue" that improves the effect of laser treatment on wounds. This improvement may be important in sensitive areas of the body, such as the intestine. Waves of muscle movement travel through the wall of the intestine to push food along its journey. The movement of muscle and food puts pressure on the intestinal wall.
There has been some concern that although lasers seal wounds rapidly, the seal might sometimes be weak, which could be serious in the intestine. Holes in the intestinal wall would allow food, enzymes and bacteria to enter the abdominal cavity. This could cause a potentially life-threatening infection and dangerous inflammation.
The Arizona researchers have created a protein-based glue that also contains gold nanoparticles. These particles are rod-shaped and are 50 nanometers long and 15 nanometers wide. (A nanometer is one billionth of a meter,) The gold rods absorb near-infrared light from a laser beam and heat up, causing the artificial proteins in the glue to coagulate. The glue therefore acts a solder when it's placed over a wound and heated by a laser.
In experiments with pig intestines, the researchers have found that their new glue solidifies into an elastic material. This material significantly increases the resistance to pressure in the intestine compared to the results of other types of laser treatment.
Wound Closure Today and in the Future
The simple technique of sewing skin sections together has helped heal wounds for thousands of years. Today improved suturing materials and techniques offer a better outcome than people in the past experienced, with less scarring. Even better techniques that produce more satisfactory results - such as laser tissue welding - may soon be common. The simple stitch has served us well over time, though, and probably will continue to do so, although perhaps in a modified form.
References and Further Reading
© 2012 Linda Crampton
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