Medical stitches, formally called sutures, come in dozens of varieties that differ by material, structure, and technique. They fall into two broad camps: absorbable stitches that dissolve on their own, and non-absorbable stitches that stay in place until a doctor removes them. Beyond those two categories, stitches vary by what they’re made of, how the thread is constructed, and the pattern used to sew them in. Understanding these differences helps make sense of what your surgeon chose and why.
Absorbable vs. Non-Absorbable Stitches
This is the most fundamental distinction. Absorbable stitches lose most of their holding strength over a period of weeks to months, then gradually dissolve inside the body. They’re the go-to choice for internal layers of tissue, deep closures, and areas where removing stitches later would be impractical. Organs that heal quickly, like the stomach, colon, and bladder, are typically closed with absorbable material. The urinary and biliary tracts specifically call for synthetic absorbable stitches because other types can promote stone formation.
Non-absorbable stitches keep their strength for at least 60 days, and many hold indefinitely. They’re used where long-term support matters: closing the tough connective tissue called fascia, repairing tendons and ligaments, anchoring tissue to bone, and reconnecting blood vessels. Skin stitches are often non-absorbable too, since they can be easily removed once the wound has healed enough on its own. When absorbable stitches are used on the skin surface, they tend to cause more inflammation and scarring, so surgeons pick fast-dissolving varieties to minimize that effect.
Natural vs. Synthetic Materials
Stitches are also grouped by what they’re made from. Natural suture materials include surgical gut (historically called catgut, though it comes from sheep or cow intestine) and silk. Synthetic options include nylon, polypropylene, and specialized polymers. The material matters because natural stitches break down through a process that triggers more inflammation at the wound site. Synthetic stitches dissolve through a chemical reaction with water, which produces a milder tissue response and more predictable absorption rates.
Polypropylene, a common synthetic non-absorbable material, is particularly useful for skin closure because it doesn’t stick to surrounding tissue. This makes it easy to pull out later, which is why it’s a popular choice for the neat, hidden stitch pattern used just beneath the skin surface (called subcuticular closure). Silk, while technically non-absorbable, does gradually lose strength over time and causes more tissue reaction than synthetic alternatives.
Monofilament vs. Braided Stitches
Beyond what a stitch is made of, its physical structure matters. A monofilament stitch is a single smooth strand, like a fishing line. It slides through tissue easily with minimal friction, which is gentler on delicate areas. The trade-off is that knots are harder to secure because the surface is so smooth, requiring extra loops to keep them from slipping. Monofilament stitches also weaken significantly if they get kinked or crushed by surgical instruments during placement.
Braided (multifilament) stitches are made from several fibers twisted or woven together into one strand. They’re generally stronger and hold knots much more reliably. The downside is more friction as they pass through tissue, and the tiny spaces between fibers can theoretically harbor bacteria. Many braided stitches come with a manufacturer-applied coating to reduce drag, though this also slightly reduces knot security.
Common Stitching Patterns
The thread is only half the equation. How it’s sewn matters just as much. The two most widely used patterns are simple interrupted and simple running stitches. In a survey of academic dermatologic surgeons, the majority reported relying on these straightforward techniques for closing skin layers.
Simple interrupted stitches are individual loops, each tied and cut separately. If one stitch fails, the rest still hold. This pattern gives the surgeon precise control over tension at each point along the wound. Simple running stitches use a single continuous thread that zigzags along the wound, which is faster to place but means the entire closure relies on one strand.
Mattress stitches are more specialized. The vertical mattress pattern grabs deep and superficial tissue in one pass, pulling wound edges slightly upward (called eversion) to promote better healing. However, it can leave visible “railroad track” marks on the skin if it creates too much tension, so surgeons avoid it in cosmetically sensitive areas like the face. The horizontal running mattress stitch achieves good eversion and blood control while distributing tension more evenly, often producing smoother, flatter scars than a simple running technique.
How Long Absorbable Stitches Last
Different absorbable materials dissolve on very different timelines. One of the fastest common options retains only 50% of its strength at 5 days and drops to zero by 10 to 14 days, fully dissolving by about 42 days. This rapid profile makes it useful for skin closures where you want the material gone quickly.
A standard braided absorbable stitch keeps about 75% of its strength at 2 weeks and 50% at 3 weeks, with complete absorption by 56 to 70 days. Longer-lasting versions of the same material hold 80% strength at 2 weeks and still retain 60% at 6 weeks, taking 6 to 8 months to fully dissolve. Surgeons match the absorption timeline to how long the tissue needs support while healing.
When Stitches Come Out
For non-absorbable skin stitches, removal timing depends on where the wound is. Areas with strong blood supply heal faster and need stitches for less time, while areas under more tension or with slower circulation need them longer:
- Face: 4 to 5 days
- Scalp: 7 to 10 days
- Arms and backs of hands: 7 days
- Chest, abdomen, or back: 7 to 10 days
- Legs and tops of feet: 10 days
- Palms, soles, fingers, or toes: 12 to 14 days
Leaving stitches in too long increases the risk of visible scarring and track marks. Removing them too early risks the wound reopening.
Suture Sizing
Stitches come in a wide range of thicknesses, labeled using a system that can seem counterintuitive. Sizes run from thick (size 7, the largest) down through 1, then shift to a “dash-zero” format: 2-0 is thinner than 1, 3-0 is thinner than 2-0, and so on down to 7-0 or even finer. The higher the number before the zero, the thinner the thread. A size 7 stitch might be used to close heavy fascia, while a 6-0 or 7-0 thread is fine enough for delicate eye or facial surgery.
Alternatives to Traditional Stitches
Not every wound needs needle and thread. Surgical staples are faster to place and more consistent in spacing, making them a practical choice for long incisions like those on the scalp or torso. They’re removed with a special tool, typically on the same timeline as stitches for that body area.
Skin glue (a medical-grade adhesive based on cyanoacrylate) is another option, primarily for smaller, superficial wounds. In comparative studies, patients closed with skin glue reported less post-operative discomfort than those who received staples or traditional stitches. The glue group also had lower infection rates, better cosmetic results at one month, and shorter hospital stays. Glue is bacteriostatic, meaning it actively discourages bacterial growth, and it peels off on its own as the wound heals, eliminating the need for a removal visit. Its main limitation is that it can’t close large or deep wounds, and it works best on cuts that run along the skin’s natural tension lines.
Adhesive wound closure strips (thin sticky tapes placed across the wound) serve as yet another option for minor cuts, sometimes used alongside stitches to add support after the primary stitches are removed.