Suturing Basics

Clinical Importance of Suturing Competency

Suturing is a fundamental procedural skill for the Family Nurse Practitioner (FNP) in outpatient, urgent care, and emergency settings. Mastery of basic suturing techniques enables the practitioner to manage simple lacerations, promote optimal wound healing, minimize infection risk, and improve cosmetic outcomes^[1]. On certification exams, suturing questions commonly test instrument identification, needle handling, suture selection, and sterile technique.

• Clinical relevance: High-volume procedure in primary and acute care.
• Exam focus: Suture types, needle anatomy, closure methods, and wound classification.

Suture Materials, Needles, and Wound Categories

Suture Materials

• Absorbable: Broken down by tissue enzymes or hydrolysis; used for deep layers (e.g., polyglactin 910 [Vicryl], poliglecaprone [Monocryl])^[2].
• Nonabsorbable: Removed after wound healing; used for skin closure (e.g., nylon, polypropylene, silk).
• Monofilament vs. Multifilament: Monofilament has lower infection risk; multifilament offers better handling but higher capillary action^[1].

Needle Anatomy

• Swaged (eyeless) needle: Suture attached to needle; most common.
• Needle point types: Cutting (for skin), reverse cutting (stronger), taper (for soft internal tissues).
• Needle body curvature: 3/8 circle (skin), 1/2 circle (deeper spaces).

Suture Size

• Measured by number of zeros (e.g., 5-0 = 00000). Larger number = smaller diameter.
• Face/lip: 6-0 nylon; scalp/extremities: 4-0 or 5-0; trunk: 3-0 or 4-0^[3].

Wound Classification

• Clean: No infection, no GI/GU entry.
• Clean-contaminated: Entry into respiratory/GI under controlled conditions.
• Contaminated: Open traumatic wounds, gross spillage.
• Dirty/infected: Pus, perforated viscus.

Suturing Steps and Tissue Handling Guidelines

Basic Suturing Steps

1. Preparation: Assemble sterile gloves, antiseptic, local anesthetic, suture kit, and appropriate suture.
2. Anesthesia: Lidocaine 1% (with or without epinephrine, avoid in fingers/toes). Maximum dose: 4.5 mg/kg (plain) / 7 mg/kg (with epi)^[4].
3. Wound cleaning and debridement: Irrigate with normal saline; remove devitalized tissue.
4. Hemostasis: Control bleeding with pressure or electrocautery before closure.
5. Closure technique:
   • Simple interrupted: Most common; allows individual suture removal.
   • Continuous (running): Faster; single knot; risk of dehiscence if one spot breaks.
   • Mattress (horizontal/vertical): Evert wound edges; used for high-tension areas.
6. Knot tying: Instrument tie (two-hand or one-hand); square knots (two throws in opposite direction).
7. Dressing: Apply sterile bandage; instruct wound care.

Key Principles

• Tissue handling: Minimize forceps crushing; handle skin edges gently.
• Edge eversion: Everting sutures reduce scarring and wound inversion.
• Depth: Include dermis to eliminate dead space.
• Spacing: Sutures placed equidistant from wound edge (2–3 mm) and 5–8 mm apart^[1].

Determining When to Close a Wound

• Indications for primary closure: Clean, non-infected lacerations <6–8 hours old (face up to 12 hours).
• Contraindications to suturing: Animal/human bites (consider delayed closure), crush injuries, infected wounds, foreign bodies not removed^[5].
• Wounds that may be left open: Heavily contaminated, puncture wounds, or immunocompromised patients.

Post-Suture Care and Antibiotic Protocols

Post-Suture Care Instructions

• Keep wound dry for 24–48 hours.
• Change dressing daily; monitor for signs of infection (erythema, warmth, purulent drainage).
• Remove sutures based on location:
  • Face: 3–5 days
  • Scalp: 7–10 days
  • Trunk/upper extremities: 10–14 days
  • Lower extremities: 14–21 days
• Advise on sunscreen use to minimize scar hyperpigmentation.

Antibiotic Prophylaxis

• Not routinely indicated for clean wounds.
• Consider for contaminated wounds, immunocompromised patients, or puncture wounds through footwear^[5].
• Tetanus prophylaxis: Update if last dose >5 years for clean wounds; >10 years for all others^[6].

Common Complications and Safe Suturing Practices

Common Complications

• Wound infection: Most common; prevention by sterile technique and timely closure.
• Dehiscence: Wound separation; risk increased with tension, infection, premature suture removal.
• Hypertrophic scar / keloid: Higher in darker skin tones; consider referral for steroid injection.
• Needlestick injury: Use blunt needles or careful handling; immediate protocol follow-up.

Safety Precautions

• Avoid epinephrine in end-artery areas (digits, nose, penis, ears).
• Use sterile technique throughout; prep skin with chlorhexidine or betadine.
• Never cut sutures too close to knot (risk of unravelling).
• Document wound appearance, location, length, depth, closure type, and suture count.

Memory Aids and Exam Scenarios for Suturing

• Memory aid: "Suture size is inversely related to number of zeros" – more zeros = smaller suture.
• High-yield fact: Simple interrupted sutures are used most often for skin; they are easy to learn and allow selective removal.
• Common exam scenario: A 5-year-old with facial laceration: use 6-0 nylon (or fast-absorbing gut), remove in 3–5 days.
• Remember contraindications: Deep lacerations involving tendons, nerves, or vessels require referral.
• Technique tip: "Evert, not invert" – everting sutures reduce scarring.
• Knot security: Square knots = two throws in opposite direction (right over left, then left over right).
• PTCE/FNP crossover: Know suture material degradation times: Vicryl (60–90 days), Monocryl (90–120 days).
• Licensing exam preference: Know that running subcuticular sutures give best cosmetic results but require more skill^[2].

References & Sources

1. Trott, A. T. (2012). Wounds and Lacerations: Emergency Care and Closure (4th ed.). Elsevier. https://doi.org/10.1016/C2009-0-64507-8
2. American College of Emergency Physicians. (2023). Clinical Policies for Wound Management. https://www.acep.org/patient-care/clinical-policies/
3. Zuber, T. J. (2002). The Mattress Sutures: Vertical, Horizontal, and Corner Stitch. American Family Physician, 66(12), 2231–2236. https://pubmed.ncbi.nlm.nih.gov/12516356/
4. Lidocaine Dosing Guidelines. UpToDate. (2024). https://www.uptodate.com/contents/lidocaine-drug-information
5. Singer, A. J., & Dagum, A. B. (2008). Current Management of Acute Cutaneous Wounds. New England Journal of Medicine, 359(10), 1051–1063. https://doi.org/10.1056/NEJMra0707253
6. Centers for Disease Control and Prevention. (2023). Tetanus Prevention – Wound Management. https://www.cdc.gov/tetanus/clinicians.html