Surgical suture is a medical device used to hold body tissues together after injury or surgery. The application generally involves using a needle with an attachable length of thread.
Biocompatibility is of prime importance, if the textile materials are to be accepted by the body and following four key factors will determine how the body reacts to the implants:
- The most important factor is porosity which determines the rate at which human tissue will grow and encapsulate the
- Small circular fibers are better encapsulated with human tissue than larger fibers with irregular cross
- Toxic substances must not be released by the fiber polymers and the fibers should be free from surface contamination like lubricants and sizing
- The property will influence the success of the implantation in terms of its
Types of sutures
The different types of sutures can be classified in many ways. First, suture material can be classified as either absorbable or non-absorbable. Absorbable sutures do not require a doctor to remove them. This is because enzymes found in the tissues of a human body naturally digest them.
Non-absorbable sutures will need to be removed by a doctor at a later date or in some cases left in permanently.
Second, the suture material can be classified according to the actual structure of the material. Monofilament sutures consist of a single thread. This allows the suture to more easily pass through tissues.
Braided sutures consist of several small threads braided together. This can lead to better security, but at the cost of the increased potential for infection.
Third, sutures can be classified as either being made from natural or synthetic material. However, since all suture material is sterilized, this distinction is not particularly useful.
Types of absorbable sutures
Gut: This natural monofilament suture is used for repairing internal soft tissue wounds or lacerations. The gut should not be used for cardiovascular or neurological The body has the strongest reaction to this suture and will often scar over. It is not commonly used outside of gynecological surgery.
- Polydioxanone (PDS): This synthetic monofilament suture can be used for many types of soft tissue wound repair (such as abdominal closures) as well as for pediatric cardiac procedures.
- Poliglecaprone (MONOCRYL): This synthetic monofilament suture is used for general use in soft tissue This material should not be used for cardiovascular or neurological procedures. This suture is most commonly used to close the skin in an invisible manner.
- Polyglactin (Vicryl): This synthetic braided suture is good for repairing hand or facial lacerations. It should not be used for cardiovascular or neurological procedures.
Types of non-absorbable sutures
Some examples of non-absorbable sutures can be found below. These types of sutures can all be used generally for soft tissue repair, including for both cardiovascular and neurological procedures.
- Nylon- a natural monofilament
- Polypropylene (Prolene)- a synthetic monofilament
- Silk- a braided natural
- Polyester (Ethibond)- a braided synthetic
Suture selection and techniques
There are many different suture techniques. Some of them are:
Continuous sutures: This technique involves a series of stitches that use a single strand of suture material. This type of suture can be placed rapidly and is also strong, since tension is distributed evenly throughout the continuous suture strand.
Interrupted sutures: This suture technique uses several strands of suture material to close the wound. After a stitch is made, the material is cut and tied off. This technique leads to a securely closed wound. If one of the stitches breaks, the remainder of the stitches will still hold the wound together.
Deep sutures: This type of suture is placed under the layers of tissue below (deep) the skin. They may either be continuous or interrupted. This stitch is often used to close fascial layers.
Buried sutures: This type of suture is applied so that the suture knot is found inside (that is, under or within the area that is to be closed off). This type of suture is typically not removed and is useful when large sutures are used deep into the body.
Purse-string sutures: This is a type of continuous suture that is placed around an area and tightened much like the drawstring on a bag. For example, this type of suture would be used in your intestines in order to secure an intestinal stapling device.
Subcutaneous sutures: These sutures are placed in the dermis, the layer of tissue that lies below the upper layer of human skin. Short stitches are placed in a line that is parallel to a wound. The stitches are then anchored at either end of the wound.
Natural sutures are made of catgut or reconstituted collagen, or from cotton, silk, or linen. Synthetic absorbable sutures may be made of polyglycolic acid, a glycolide-lactide copolymer; or polydioxanone, a copolymer of glycolide and trimethylene carbonate. These different polymers are marketed under specific trade names.
Synthetic nonabsorbable sutures may be made of polypropylene, polyester, polyethylene terephthalate, polybutylene terephthalate, polyamide, different proprietary nylons, or Goretex. Some sutures are also made of stainless steel.
The manufacturing processes
|The manufacturing processes of surgical suture|
|Preparation of raw polymer-||Raw polymers are combined (polymerized), forced through a die and discharged as tinny pellets.|
|Forming individual filaments by extruder machine –||The machine melts the polymer, and the liquid flows through the tiny spinneret (looking something like a shower head) forming many individual filaments.|
|Drawing of filaments-||After extrusion, the filaments are stretched between two rollers. The filaments stretch to as much as five times their original length.|
|Manufacturing of sutures-||Some sutures are produced as monofilaments. Others are braided or twisted. To braid the suture, the extruded monofilament is wound onto bobbins.|
|Secondary processing-||After braiding, the suture undergoes several stages of secondary processing. Non-braided sutures will also go through these steps after extrusion and initial stretching. This step might take only a few minutes. The suture passes over a hot plate, and any lumps, snags, or imperfections are ironed out.|
|Annealing-||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.|
|Coating-||After annealing, the suture may be coated. The coating material varies depending on what the suture is made of. Absorbable coatings include Poloxamer 188 and calcium stearate with a glycolide-lactide copolymer. Nonabsorbable sutures may be coated with wax, silicone, fluorocarbon, or polytetramethylene adipate.|
|Quality control-||This step the suture conforms to the proper diameter, length, and strength, look for physical defects, and check the dissolvability of an absorbable suture in animal and test-tube tests. If the batch passes all the tests, it is shipped.|
|Surgical needle preparation-||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.|
|Sterilization-||Next, the suture and attached needle are inserted into a foil packet and sterilized. Sterilization differs according to the suture material.|
When sutures are removed will depend on where they are on a human body. According to American Family Physician, some general guidelines are as follows:
- scalp: 7 to 10 days
- face: 3 to 5 days
- chest or trunk: 10 to 14 days
- arms: 7 to 10 days
- legs: 10 to 14 days
- hands or feet: 10 to 14 days
- palms of hands or soles of feet: 14 to 21 days
To remove sutures, the doctor will first sterilize the area. They’ll pick up one end of a suture and cut it, trying to stay as close to the skin as possible. Then, they’ll gently pull out the suture strand.