I now have comprehensive data from Bailey & Love's Surgery (28th Ed), Pye's Surgical Handicraft (22nd Ed), and StatPearls. Here is a full, well-structured answer:
Types of Sutures
Sutures are classified along three main axes: absorbability, material origin, and physical structure.
1. Classification by Absorbability
Absorbable Sutures
Break down in the body over time - either by proteolysis (natural sutures) or hydrolysis (synthetic sutures). Hydrolysis causes less inflammation than proteolysis.
Used for: deep tissue closure, rapidly healing tissues (GI tract, subcutaneous layers), urinary/biliary tracts, tying off small vessels.
| Suture | Trade Name | Structure | Absorption Time | Key Uses |
|---|
| Catgut (plain) | - | Twisted multifilament | ~7-10 days | Soft tissue approximation only |
| Chromic catgut | - | Twisted multifilament | 2-3 weeks | Extended use vs. plain gut |
| Polyglactin 910 | Vicryl | Braided multifilament | 40-90 days | Intestinal anastomoses, soft tissue |
| Polyglycolic acid | Dexon | Braided multifilament | 60-90 days | Similar to Vicryl |
| Polydioxanone | PDS | Monofilament | 50% strength at 4 wks; absorbed by 6 months | Fascial closure, subcuticular, GI anastomoses |
| Poliglecaprone 25 | Monocryl | Monofilament | ~91-119 days | Subcuticular, intradermal |
| Polyglyconate | Maxon | Monofilament | ~180 days | Similar to PDS |
PDS is notable for retaining tensile strength over several weeks (50% at 4 weeks), making it suitable where prolonged support is needed. - Pye's Surgical Handicraft, 22nd Ed.
Natural absorbable sutures do very badly in the GI tract. - StatPearls / NCBI
Non-Absorbable Sutures
Remain walled off by the body's inflammatory processes or must be removed manually. Synthetic non-absorbables (e.g. polypropylene) retain tensile strength indefinitely; biological ones (e.g. silk) fragment over time.
| Suture | Trade Name | Structure | Tissue Reaction | Key Uses |
|---|
| Silk | - | Braided multifilament | Moderate-high | Ligation, drain securing, GI anastomoses |
| Nylon | Ethilon, Dermalon | Mono or braided | Low | Skin closure, neurosurgery, microsurgery, ophthalmic |
| Polypropylene | Prolene, Surgipro | Monofilament | Low | Vascular surgery, subcuticular closure, plastic surgery |
| Polyester | Ethibond, Ticron | Braided multifilament | Low | Cardiovascular, ophthalmic, general surgery |
| Surgical steel | - | Monofilament | Minimal | Sternotomy closure, tendon repair |
| Linen | - | Braided multifilament | Moderate | GI surgery (rarely used now) |
Non-absorbable materials of synthetic origin such as polypropylene probably retain their tensile strength indefinitely, whereas biological non-absorbables like silk will fragment with time - they should never be used in vascular anastomoses due to risk of late fistula formation. - Bailey & Love's Surgery, 28th Ed.
2. Classification by Material Origin
| Type | Description | Examples |
|---|
| Natural | Derived from animal/plant tissues | Catgut (sheep submucosa), silk (silkworm), linen |
| Synthetic | Man-made polymers | Vicryl, PDS, Monocryl, Prolene, nylon, polyester |
- Natural sutures degrade by proteolysis - more unpredictable and inflammatory
- Synthetic sutures degrade by hydrolysis - more predictable, less inflammatory
3. Classification by Physical Structure
| Structure | Properties | Examples |
|---|
| Monofilament | Smooth, slides easily through tissue, harder to knot, less infection risk | Prolene, PDS, Monocryl, nylon (Ethilon) |
| Multifilament / Braided | Easy to knot, high capillary action - bacteria can lodge in interstices, risk of infection | Vicryl, silk, polyester |
| Barbed (knotless) | Self-anchoring, no knot needed, used in laparoscopic/robotic surgery | Stratafix, Quill, Durabarb |
Multifilament sutures have a surface area several thousand times that of monofilament sutures and thus have capillary action where bacteria may lodge - some are coated with silicone to reduce this risk. - Bailey & Love's Surgery, 28th Ed.
4. Suture Size
Size is expressed in USP (United States Pharmacopeia) notation - the more zeros, the finer the suture:
| Metric | Diameter (mm) | USP |
|---|
| 1 | 0.100-0.149 | 5-0 |
| 1.5 | 0.150-0.199 | 4-0 |
| 2 | 0.200-0.249 | 3-0 |
| 3 | 0.300-0.349 | 2-0 |
| 3.5 | 0.350-0.399 | 0 |
| 4 | 0.400-0.499 | 1 |
The smallest suture possible for the tissue being closed should always be used.
5. Five Key Characteristics of Any Suture (Bailey & Love's Framework)
- Physical structure - monofilament vs. multifilament
- Strength - tensile strength by diameter and material
- Tensile behaviour - elastic vs. plastic deformation; "memory" (coiling tendency)
- Absorbability - absorbable vs. non-absorbable
- Biological behaviour - tissue reaction: proteolysis (natural) vs. hydrolysis (synthetic)
6. Clinical Selection Guide
| Situation | Preferred Suture |
|---|
| Vascular anastomosis | Smooth, non-absorbable, non-elastic (e.g. Prolene) |
| Biliary anastomosis | Absorbable, minimal reaction, no stone formation |
| Bowel anastomosis | Vicryl, PDS, or polypropylene |
| Abdominal wall / fascial closure | PDS (mass closure) |
| Subcuticular skin closure | PDS or Prolene |
| High infection risk | Monofilament absorbable |
| Cosmetically sensitive skin | Smallest monofilament absorbable |
| Tendon / fascia | Non-absorbable or slow-absorbing (PDS) |
| Securing a drain | Silk |
Sources: Bailey & Love's Short Practice of Surgery, 28th Ed. |
Pye's Surgical Handicraft, 22nd Ed. |
StatPearls - Sutures and Needles (NCBI) |
TeachMeSurgery - Suture Materials