The purpose of a suture
- to hold a wound together in good apposition until such time as the
natural healing process is sufficiently well established to make the
support from the suture material unnecessary and redundant.
Ideal suture material
- The ideal suture material should:
- Have good handling characteristics
- Not induce a significant tissue reaction
- Allow secure knots
- Have adequate tensile strength
- Not cut through tissue
- Be sterile
- Be non-electrolytic
- Be non-allergenic
- Cheap and sterile
Choice of a suture
- Choice of suture depends on:
- Properties of suture material
- Absorption rate
- Handling characteristics and knotting properties
- Size of suture
- Type of needle
Natural suture materials
- Non-Absorbable
- Silk
- Linen
- Stainless Steel Wire
Synthetic suture materials
- Absorbable
- Polyglycolic Acid (Dexon)
- Polyglactin (Vicryl)
- Polydioxone (PDS)
- Polyglyconate (Maxon)
- Non-Absorbable
- Polyamide (Nylon)
- Polyester (Dacron)
- Polypropylene (Prolene)
Absorbable suture are broken down by either:
- Proteolysis (e.g. Catgut)
- Hydrolysis (e.g. Vicryl, Dexon)
Suture characteristics
- Suture materials vary in their physical characteristics
- Monofilament sutures (e.g. polypropylene) are smooth
- The slide well in tissues but if handles inappropriately they can
fracture
- Multifilament sutures (e.g. polyglactin) are braided
- They have a greater surface area
- They are easier to handle and knot well
- Some suture materials have a 'memory' (e.g. polypropylene)
- Return to former shape when tension is removed
Catgut
- Was made from the submucosa of sheep gastrointestinal tract
- Broken down within about one week
- Chromic acid delays hydrolysis
- Catgut has been replaced by synthetic absorbable polymers
Silk
- Strong and handles well but induces strong tissue reaction
- Capillarity encourages infection causing suture sinuses and
abscesses
Vicryl
- Tensile strength
- 65% @ 14 days
- 40% @ 21 days
- 10% @ 35 days
- Absorption complete by 70 days
Polydioxone
- Tensile strength
- 70% @ 14 days
- 50% @ 28 days
- 14% @ 56 days
- Absorption complete by 180 days
Suture sizes
- Sutures are sized by the USP (United States Pharmacopoeia) scale
- The available sizes and diameters are:
- 6-0 = 0.07 mm
- 5-0 = 0.10 mm
- 4-0 = 0.15 mm
- 3-0 = 0.20 mm
- 2-0 = 0.30 mm
- 0 = 0.35 mm
- 1 = 0.40 mm
- 2 = 0.5 mm
Needle points
- Five types of needle points are in common use
- Conventional cutting needle
- Reverse cutting needle
- Round-body taper-point needle
- Taper cutting needle
- Blunt point needle
- Needles vary
- Diameter of the curve
- Circumference of the curve
- Sutures can be attached to an needle by either an eye or a swage
Common errors of suture use
- Too many throws. Increases foreign body size. Causes stitch
abscesses
- Intra-cuticular rather than subcuticular sutures causing
hypertrophic scars
- Holding monofilament sutures with instruments reduces tensile
strength by over 50%
- Holding butt of needle causes needle and suture breakage
Other techniques of wound closure
- Steristrips
- Steristrips are self adhesive tapes
- Useful if there is potential tension on a wound
- Useful for superficial lacerations
- Can cause skin blisters
- Tissue adhesive
- Based on cyanoacrylate monomer
- Wounds need to be clean and tension free
Bibliography
Coulthard P, Worthington H, Esposito M et al. Tissue
adhesive for closure of surgical incisions. Cochrane Database
Syst Rev 2004; CD004287.
Hochberg J, Meyer K M, Marion M D. Suture choice and
other methods of skin closure. Surg Clin North Am 2009;
89: 627-641.
Hsiao W C, Young K C, Wang S T, Lin P W.
Incisional hernia after laparotomy: randomised comparison between
early-absorbable and late-absorbable suture materials. World J
Surg 2000; 24: 747-751. |