Wound Closure

1. THE 2-MINUTE PHYSIOLOGY (Rapid Pathophysiology)

• The Mechanical Breach: A traumatic laceration or wound represents a physical disruption of the skin's complex barrier, which normally protects against bacterial invasion, regulates water content, and provides thermoregulation.
• The Healing Cascade: Normal wound healing involves a complex cascade designed to repair the mechanical defect. However, wound desiccation (drying out) results in further epidermal necrosis, crust formation, and heightened inflammation.
• The Goal of Closure: The emergency provider's goal is to mechanically bridge this defect to prevent excessive or prolonged inflammation, avoid bacterial infection, and minimize scar formation.

2. THE BEDSIDE ACTION PLAN (Rapid ER Management)

• Immediate Hemorrhage Control (xABCDE): Treat the greatest threat to life first by addressing active, large-volume, compressible external hemorrhage ("x" in the primary survey) with the tiered application of direct pressure, wound packing, and extremity tourniquet application.
• Preparation & Positioning: Remove rings or other circumferential jewelry immediately before progressive swelling turns them into ischemic constricting bands. Cut—do not shave—surrounding hair to prevent micro-abrasions, and prepare the skin with a chlorhexidine-alcohol solution.
• Anesthesia & The Bloodless Field: Perform a full neurovascular examination, then anesthetize the wound using local or regional blocks (e.g., Bupivacaine 0.5% without epinephrine). Utilize a tourniquet or sphygmomanometer on extremities to achieve a bloodless field for optimal visualization.
• Debridement & Irrigation: Perform sharp debridement of foreign matter and devitalized tissue. Irrigate under high pressure using normal saline, clean tap water, or a 1% povidone-iodine solution.
• Closure & Pharmacotherapy: Close the defect using tape, tissue adhesives, staples, or sutures (absorbable or non-absorbable). Do not use subcutaneous (deep) sutures unless the wound is under high tension. Apply topical antibiotics, update tetanus prophylaxis, and strictly avoid systemic antibiotics unless the wound is deemed high risk.

3. THE DIAGNOSTIC GRID (Differential Diagnosis & Workup)

• Top "Can't-Miss" Hidden Pathologies:
• Retained Foreign Bodies: A leading cause of malpractice claims; missed wood, glass, or metal can lead to severe delayed infections.
• Tendon & Nerve Lacerations: Missed deep structural injuries often result from failing to achieve a bloodless field or adequately exploring the wound through the full range of motion.
• Open Fractures / Joint Space Violation: High-energy injuries (like gunshot wounds) overlying bones must be treated as open fractures requiring systemic prophylactic antibiotics due to the vacuum effect of cavitation drawing in contaminants.
• Prioritized Diagnostic Workup:
• Tier 1 (Clinical): Direct, visually optimized, bloodless exploration of the wound base to assess fascia, muscles, bone, cartilage, and ducts.
• Tier 2 (Imaging): Plain X-ray films to detect underlying fractures or radiopaque foreign bodies.
• Tier 3 (Bedside POCUS): Point-of-care ultrasound to localize radiolucent foreign bodies, evaluate for underlying vascular injury, or assess tendon integrity.

4. THE VISUAL BOARD (ECG / POCUS / Imaging)

• The Deep Exploration: You must physically visualize the absolute base of the wound. Blindly suturing a wound without visualizing the underlying bone, muscle, or tendon risks catastrophic functional loss.
• High-Risk Cosmetic Zones: Visually map out wounds crossing cosmetically critical landmarks such as the eyelid margins, the vermillion border of the lip, the nose, or the ear, as these often require complex layered repairs or specialty consultation.
• POCUS for Foreign Bodies: On bedside ultrasound, look for a hyperechoic structure with posterior acoustic shadowing or a "halo" artifact, which confirms a retained foreign body that may have been missed on a plain radiograph.

5. THE SCORING MATRIX (Risk Stratification & Guidelines)

• The Closure Timeline Matrix:
• Primary Closure: Indicated for clean, relatively fresh wounds with viable tissue margins.
• Delayed Primary Closure: Dirty, highly contused extremity wounds presenting late (e.g., >18 hours post-injury) are ideal candidates for delayed primary closure. These wounds are anesthetized, scrubbed, irrigated, and sharply debrided in the ED, but left open to be definitively closed a few days later.
• Do Not Close: Strongly consider leaving human bites, deep puncture wounds, and highly infected/purulent wounds open to heal by secondary intention.

6. THE DANGER ZONE (Pitfalls & Critical Actions)

• Pitfall - The Pre-Anesthesia Neurologic Miss: Injecting local anesthesia before documenting sensory and motor function. Critical Action: A thorough neurovascular examination must be documented prior to the administration of any anesthetic agent.
• Pitfall - The Shaving Trap: Shaving the skin around a laceration (especially the eyebrow) to clear the field. Critical Action: Never shave the hair; this introduces micro-lacerations and significantly increases infection risk. Always cut or clip the hair instead.
• Pitfall - Overusing Deep Sutures: Reflexively placing subcutaneous absorbable sutures in all deep wounds. Critical Action: Subcutaneous sutures act as foreign bodies and increase infection risk; they should only be used if the wound is under high tension.
• Pitfall - Systemic Antibiotic Abuse: Prescribing oral antibiotics for routine, uncomplicated lacerations. Critical Action: Systemic antibiotics are generally not indicated unless the wound is high-risk, grossly contaminated, or involves an open fracture.

7. MCQ MASTERCLASS (Written Exam Tips)

• Buzzwords: "Dirty and contused extremity wound," "18 hours old." Answer: Delayed primary closure.
• Common Distractor: A patient presents with a deep forehead laceration. An option suggests: "Shave the surrounding hair and prep with povidone-iodine." Differentiate: This is a trap. You must cut the hair, never shave it, to prevent localized infection.
• Common Distractor: A question asks for the appropriate use of subcutaneous sutures in a deep, 4-cm forearm laceration. An option states: "Use subcutaneous sutures to close the dead space and prevent hematoma." Differentiate: The textbook explicitly states to avoid subcutaneous sutures unless the wound is under high tension, as they increase the risk of infection.

8. THE BOARDROOM SCRIPT (OSCE & Oral Board Tips)

• The Opening Salvo: "My first priority is the primary survey, specifically looking for exsanguinating external hemorrhage that requires immediate direct pressure or a tourniquet. Concurrently, I will ensure all rings and circumferential jewelry are removed from the affected extremity before swelling ensues."
• Articulating the Preparation: "I will perform and document a complete neurovascular examination of the extremity. I will then anesthetize the wound with 0.5% Bupivacaine and utilize a tourniquet to establish a bloodless field, which is critical to properly explore for occult tendon, nerve, or vascular injuries."
• Formulating the Closure: "After clipping the surrounding hair and prepping the skin with chlorhexidine, I will perform sharp debridement of devitalized tissue and high-pressure irrigation. Given that this is a clean wound under low tension, I will close it primarily with non-absorbable interrupted sutures without placing deep subcutaneous stitches."
• The Disposition: "I will update the patient's tetanus prophylaxis and apply a topical antibiotic ointment. I will explicitly not prescribe systemic oral antibiotics. I will discharge the patient with clear instructions on gentle wound cleansing, signs of infection, and a specific timeline for suture removal."