Introduction
Suture selection directly affects surgical site infection rates, closure time, and cosmetic outcomes. Research shows monofilament sutures reduce infection risk by approximately 29% compared to braided alternatives, making material choice a critical clinical decision that balances speed, safety, and patient satisfaction.
Nylon (polyamide) monofilament sutures remain one of the most widely used non-absorbable materials for skin closure across general, plastic, ophthalmic, and neurological surgery. Their high tensile strength, smooth surface, and minimal tissue reactivity have made them the standard for decades.
The landscape is shifting. Modern bioabsorbable closure systems now offer comparable outcomes with significant efficiency advantages, challenging traditional suturing methods while eliminating removal procedures entirely.
TLDR: Key Takeaways About Nylon Sutures
- Nylon monofilament sutures meet USP standards with tensile strength from 0.4-3.5 lbs depending on size
- Ideal for skin closure across facial, scalp, trunk, and extremity procedures with low tissue reactivity
- Lower infection risk: Monofilament structure reduces bacterial adherence by 29% compared to braided sutures
- Requires removal within 3-14 days depending on location, necessitating follow-up visits
- Costs 67% less than absorbables but requires removal appointments and proper knot technique
What Are Nylon Sutures? Properties and Characteristics
Nylon (polyamide) monofilament sutures are non-absorbable synthetic sutures consisting of a single smooth thread made from long-chain polymers (Nylon 6 or Nylon 6,6).
The FDA and USP classify them as sterile surgical sutures, manufactured in sizes ranging from USP 2 (heavy) to 11-0 (microsurgical), typically dyed black or green for visibility.
High Tensile Strength
Nylon sutures consistently meet United States Pharmacopeia (USP) <881> tensile strength requirements. Common sizes demonstrate reliable knot-pull strength:
- Size 8-0: ~0.4 lbs
- Size 6-0: ~0.7 lbs
- Size 4-0: ~1.5 lbs
- Size 2-0: ~3.0 lbs
- Size 0: ~3.5 lbs
Polypropylene exhibits higher ultimate tensile strength (~12 N vs ~8 N for comparable sizes), but nylon offers superior handling characteristics and lower memory.
However, nylon loses approximately 15-20% strength per year through hydrolysis (water-based breakdown), making it unsuitable where permanent retention of tensile strength is required.
Smooth Monofilament Surface
The single-strand construction reduces tissue drag and trauma during passage. Its smooth surface creates less friction compared to braided alternatives, facilitating easier needle passage.
Monofilament design also prevents bacterial colonization within strand gaps—a significant advantage over multifilament materials.
Minimal Tissue Reactivity
Nylon monofilament demonstrates extremely low inflammatory response. Clinical studies consistently show that monofilament sutures cause significantly fewer tissue reactions than multifilament or braided options. Silk sutures trigger severe foreign body reactions due to their natural protein composition. In contrast, nylon remains relatively inert throughout the healing process.
Knot Security Considerations
The smooth surface and material "memory" create specific handling requirements. In vitro testing indicates nylon requires a minimum of 4-5 throws to achieve secure knots, compared to 3 throws for braided materials. Surgeon's knots demonstrate significantly stronger holding power than square knots for nylon (p < 0.0001). Clamping the strand with instruments can reduce breaking strength by up to 10% if a knot forms at the damaged point.
Clinical Applications of Nylon Sutures in Skin Closure
General Surgery Applications
Nylon serves as the preferred material for closing skin incisions and subcutaneous tissues in abdominal, thoracic, and general surgical procedures. Its high tensile strength ensures secure tissue approximation during healing, particularly in areas requiring long-term support.
Removal timing guidelines by location:
| Anatomic Location | Removal Time |
|---|---|
| Face | 3-5 days |
| Scalp | 7-10 days |
| Arms | 7-10 days |
| Trunk/Torso | 10-14 days |
| Legs | 10-14 days |
| Hands/Feet | 10-14 days |
| Palms/Soles | 14-21 days |
Timely removal prevents "railroad track" scarring while avoiding premature dehiscence in high-tension areas.
Plastic and Reconstructive Surgery
When cosmetic outcomes are paramount, nylon excels as a closure material. A randomized trial comparing 5-0 nylon versus 5-0 rapid-absorbing polyglactin for facial Mohs defects found no significant difference in scar appearance at 6 months using the Patient and Observer Scar Assessment Scale (p = 0.72).
The monofilament structure minimizes tissue reaction, contributing to reduced scarring compared to braided alternatives.
Timing presents a critical balance. Leaving sutures in place too long increases suture mark risk, while premature removal (< 7 days for high-tension areas) risks dehiscence. Surgeons must weigh these competing concerns based on wound location and tension.
Ophthalmic and Neurological Surgery
In specialized surgical fields, nylon's unique properties address specific technical demands.
Ophthalmic applications rely on 10-0 nylon as the standard for corneal transplantation and laceration repair. Key advantages include:
- Elasticity and inertness ideal for delicate eye tissue
- Reduced unintended corneal shape changes versus polyester alternatives
- Placement at 80-90% depth prevents creating infection conduits
Studies confirm 10-0 nylon minimizes astigmatic shifts in the early postoperative period.
Neurological applications center on scalp closure following craniotomy. Institutional protocols typically specify removal at 7-10 days, with some centers recommending 10-14 days for posterior fossa craniotomies. When combined with chlorhexidine cleansing, nylon sutures have demonstrated surgical site infection rates below 1.5%.
Advantages and Limitations of Nylon Sutures
Key Advantages
Lower infection risk: Meta-analysis of cesarean sections found monofilament sutures reduced surgical site infection risk by approximately 29% compared to multifilament sutures (RR = 0.71; 95% CI 0.52–0.98).
The smooth surface lacks tiny spaces where bacteria can harbor and multiply.
Consistent wound closure: High tensile strength holds tissues effectively throughout the healing process. Nylon maintains adequate strength for the critical early healing phase, though it gradually degrades over years through hydrolysis.
Cost-effectiveness: Nylon costs approximately 67% less than synthetic absorbables. One procurement study found material savings of $4.50 per wound compared to absorbable alternatives ($2.20 for nylon vs. $6.70 for Monocryl), potentially saving over $2,400 annually for high-volume procedures.
Important Limitations and Considerations
Removal requirement: Non-absorbable nature necessitates follow-up visits, creating additional healthcare costs, patient anxiety, and potential discomfort.
While material costs are lower, the total cost of care includes clinic time and patient travel for removal appointments.
Handling challenges: The stiffness and memory of monofilament nylon make handling more difficult than braided materials.
Less experienced surgeons may struggle with proper placement and knot tying, particularly in tight surgical fields.
Knot slippage risk: The smooth surface requires meticulous technique with multiple throws (typically 5-6) to ensure security.
Bench tests show fewer throws create unpredictable knot security, and high-tension scenarios often require complex throw combinations.
Best Practices for Using Nylon Sutures in Skin Closure
Successful nylon suture placement requires attention to sterile technique, proper knot mechanics, and patient-specific considerations. Following these evidence-based practices minimizes complications and optimizes cosmetic outcomes.
Maintain strict sterile technique: Proper aseptic handling prevents infections and promotes effective healing. Contamination during placement negates the monofilament advantage against bacterial adherence.
Master proper knot-tying technique:
- Use a surgeon's knot plus at least 3 additional square throws (total 4-5 throws minimum)
- Avoid clamping the suture strand with instruments, which reduces breaking strength by up to 10%
- Ensure adequate tension without excessive tightness that could cause tissue ischemia
Provide comprehensive aftercare instructions:
- Keep wounds clean and dry for 24-48 hours post-procedure
- Cleanse with chlorhexidine or saline as directed
- Monitor for signs of infection (increased redness, warmth, drainage, or pain)
- Schedule timely removal based on anatomic location
- Educate patients that early removal risks dehiscence while delayed removal increases scarring
Select appropriate suture size:
- Face: 5-0 or 6-0 nylon
- Scalp: 3-0 or 4-0 nylon
- Trunk/Extremities: 3-0 or 4-0 nylon
- Ophthalmic: 10-0 nylon for corneal procedures
For procedures where suture removal poses challenges or patient compliance is a concern, bioabsorbable closure systems offer an alternative that eliminates removal appointments while maintaining closure integrity.
Alternatives to Traditional Nylon Sutures
Absorbable Sutures
Polyglycolic acid (PGA), polyglactin, and poliglecaprone eliminate removal requirements by degrading naturally over weeks to months. Multiple RCTs confirm cosmetic outcomes equivalent to nylon for facial and hand surgery.
However, absorbables cost approximately 3X nylon's price and may not provide adequate long-term support for high-tension closures.
Other Non-Absorbable Options
Polypropylene offers higher tensile strength (~12 N vs ~8 N) and maintains strength indefinitely. Nylon degrades 15-20% annually. Recent evidence suggests polypropylene resists biofilm formation more effectively than nylon (p=0.001). However, its higher memory and plasticity make handling more challenging.
Silk carries infection rates of 8% compared to 0% for nylon in one study (p < 0.05). It's also associated with severe foreign body reactions. Silk is no longer recommended for cutaneous closure in modern surgical practice.
Modern Bioabsorbable Subcuticular Closure Systems
While traditional non-absorbables like polypropylene and silk have clear limitations, modern bioabsorbable systems address both speed and cosmetic concerns.
SubQ It! combines stapler speed with absorbable technology. The system deploys bioabsorbable PLGA fasteners subcutaneously in just 7 seconds per fastener—7X faster than manual sutures (which average 42 seconds per stitch). This translates to approximately 4 minutes total closure time versus 9 minutes for traditional suturing.
Key advantages:
- Eliminates removal appointments and associated costs
- Never pierces external skin, minimizing visible scarring
- FDA-cleared for abdominal, thoracic, gynecologic, orthopedic, and plastic/reconstructive surgery
- Maintains 80% strength for 21 days before natural absorption
- 2% infection rate in clinical studies
The system is available in two models for different incision lengths: up to 10cm for laparoscopic procedures and up to 25cm for larger surgical closures.
Frequently Asked Questions
Can nylon suture be used on skin?
Yes, nylon sutures are commonly used for skin closure due to their high tensile strength, minimal tissue reaction, and smooth monofilament structure. They're particularly effective for facial, scalp, trunk, and extremity closures.
When should nylon sutures be removed after skin closure?
Removal timing depends on wound location. Facial sutures should be removed in 3-5 days, scalp and arm sutures in 7-10 days, trunk/leg/hand/foot sutures in 10-14 days, and palms/soles in 14-21 days.
What is the difference between nylon and absorbable sutures for skin closure?
Nylon is non-absorbable and requires removal, while absorbable sutures dissolve naturally over weeks to months. Nylon costs approximately 67% less but requires follow-up visits, while absorbables offer convenience with comparable cosmetic outcomes.
Are nylon sutures more prone to infection than other types?
No, nylon monofilament actually has lower infection risk than multifilament options. The smooth surface resists bacterial adherence, reducing surgical site infections by approximately 29% compared to braided sutures.
What makes nylon sutures difficult to work with?
The stiffness and smooth surface create handling challenges and increase knot slippage risk. Nylon requires 4-5 throws minimum to ensure security, and the material's memory makes it spring back during tying.
How do I choose between nylon sutures and modern closure alternatives?
Choose nylon for cost-effectiveness and high-tension areas when follow-up is already planned. Select absorbables for anxious patients, children, or when removal visits are impractical. Consider bioabsorbable closure systems like SubQ It! when speed (7X faster) and superior cosmetic outcomes justify the investment.
