Skin lacerations from acute trauma represent one of the most common emergency presentations in canine practice.
Overview and Clinical Importance
Skin lacerations from acute trauma represent one of the most common emergency presentations in canine practice. A laceration is defined as a wound with torn or jagged edges resulting from blunt or sharp trauma that disrupts the continuity of skin and potentially deeper tissues. Understanding proper wound assessment, classification, and management principles is essential for successful outcomes and is frequently tested on the NAVLE.
Traumatic wounds in dogs may result from motor vehicle accidents, bite wounds, sharp objects (barbed wire, glass, metal), falls, and other external forces. The severity of injury is frequently underestimated initially, as extensive damage to underlying tissues can occur even with minimal visible skin involvement.
| Wound Type |
Characteristics |
Clinical Considerations |
| Laceration |
Sharp or jagged edges; linear or irregular; minimal tissue necrosis |
Often suitable for primary closure if clean and recent |
| Avulsion |
Tissue pulled free from attachments; tensile forces; variable damage |
Assess viability; may require extensive debridement |
| Degloving/Shearing |
Obliquely directed forces; high friction (motor vehicle); severe injury |
High infection risk; often requires reconstructive surgery |
| Puncture/Bite |
Small surface wounds; extensive underlying damage; dead space |
'Tip of iceberg' - always explore; never close primarily |
Wound Types and Etiology
| Class |
Description |
SSI Risk |
| I: Clean |
No inflammation; sterile technique; GI/GU/respiratory tracts not entered |
1-5% |
| II: Clean-Contaminated |
Controlled entry into GI/GU/respiratory; wounds less than 6 hours old with minimal contamination |
3-11% |
| III: Contaminated |
Major break in sterile technique; fresh traumatic wounds 6-12 hours old; acute non-purulent inflammation |
10-17% |
| IV: Dirty/Infected |
Established infection; devitalized tissue; wounds greater than 12 hours old; purulent material |
Greater than 27% |
Wound Classification System
The CDC Surgical Wound Classification System categorizes wounds into four classes based on contamination level:
NAVLE TipRemember 'TIME, TRASH, TRAUMA' when evaluating wounds. Time = age of wound; Trash = contamination level; Trauma = extent of tissue damage. This framework guides closure method selection.
| Phase |
Timeline |
Key Events |
| 1. Hemostasis |
Immediate (minutes) |
Vasoconstriction then vasodilation; platelet aggregation; fibrin clot formation |
| 2. Inflammatory |
Days 1-5 |
Neutrophil influx (first 24-48h); macrophage dominance (days 3-5); phagocytosis. Signs: Redness, Heat, Swelling, Pain |
| 3. Proliferative |
Days 4-21 |
Granulation tissue formation; angiogenesis; fibroplasia; epithelialization; wound contraction (0.6-0.75 mm/day) |
| 4. Remodeling |
Day 21 to 1-2 years |
Collagen reorganization; increased tensile strength; scar maturation. Final strength: only 80% of original |
Phases of Wound Healing
High-YieldMacrophages are ESSENTIAL for wound healing - they transition the wound from inflammation to repair by secreting growth factors and attracting mesenchymal cells. This is a key NAVLE concept!
| Parameter |
Recommendation |
| Optimal Pressure |
7-8 psi (pounds per square inch) |
| Delivery Method |
35-60 mL syringe with 18-19 gauge needle |
| Volume |
500 mL to 1 liter minimum |
| Primary Solution |
Sterile saline (0.9% NaCl) or Lactated Ringer's Solution |
| Chlorhexidine |
Dilute to 0.05% (1:40); broad spectrum; sustained residual activity |
| Povidone-iodine |
Dilute to 0.1-1% (1:10); effective but minimal residual activity |
Initial Wound Management
Patient Assessment and Stabilization
Patient stabilization is the FIRST priority before wound management. Trauma may have damaged other structures. Complete cardiovascular stabilization is required before sedation for wound care.
- Primary survey: ABC assessment; control hemorrhage with direct pressure
- Secondary survey: Full physical exam; radiographs to assess underlying damage
- Wound coverage: Apply sterile lubricant and moist dressing
- Pain management: Appropriate analgesia before wound manipulation
Wound Lavage Technique
Wound lavage is one of the most critical steps in wound management. The 'golden period' is the first 6 hours after injury.
High-YieldNEVER use hydrogen peroxide for wound lavage - it is cytotoxic to healthy tissue. Surgical scrub agents should also be avoided. Remember: 'The solution to pollution is dilution.'
| Closure Type |
Indications |
Requirements |
| Primary Closure |
Clean wounds less than 6-8 hours old; minimal contamination; patient stable |
Thorough lavage/debridement; layer closure; viable tissue edges |
| Delayed Primary |
Borderline contamination; moderate trauma; wounds 3-5 days after initial management |
Daily bandage changes; healthy wound bed; before granulation tissue |
| Secondary Closure |
Granulation tissue present; greater than 5 days; previous infection resolved |
Healthy granulation bed; excision of granulation edges |
| Second Intention |
Heavily contaminated; insufficient skin; young animals heal well |
Open wound management; daily bandage changes; longer healing time |
Wound Closure Options
NAVLE TipWhen in doubt, leave the wound open. A wound left open that could have been closed will still heal; a wound closed inappropriately may develop serious complications.
Suture Patterns for Skin Closure
Suture Material Selection
High-YieldIn contaminated wounds, AVOID multifilament sutures (braided silk, Vicryl) - interstices harbor bacteria. Use monofilament sutures in potentially contaminated tissues.
| Pattern |
Advantages |
Best Used When |
| Simple Interrupted |
Higher tensile strength; selective removal; if one fails, others remain |
Moderate to high tension areas; traumatic wounds |
| Cruciate/Mattress |
Distributes tension; good for fragile tissue |
Thin or friable skin; where simple interrupted fails |
| Continuous Intradermal |
No removal needed (absorbable); reduced scarring; better cosmesis |
Clean elective wounds; low-tension areas |
| Walking Sutures |
Reduces dead space; decreases tension; tacks dermis to fascia |
Large skin defects on trunk; tension relief needed |
Bandaging: Three-Layer System
NAVLE TipWet-to-dry bandages are for DEBRIDEMENT phase only. Once healthy granulation tissue is present, switch to NON-ADHERENT dressings to preserve the granulation bed!
| Layer |
Size |
Material |
| Fascia |
2-0 (3-0 small dogs) |
PDS or Biosyn (monofilament absorbable) |
| Subcutaneous |
3-0 (4-0 small) |
PDS, Biosyn, or Monocryl |
| Skin (External) |
3-0 to 4-0 |
Prolene, Nylon, or Staples (non-absorbable); remove in 10-14 days |
Pharmacological Management
Antibiotic Therapy
High-YieldCulture and sensitivity is recommended for: deep infections, recurrent infections, non-responsive to empirical therapy, and suspected MRSP. MRSP is resistant to ALL beta-lactam antibiotics!
| Layer |
Function |
Materials |
| Primary (Contact) |
Direct wound contact; prevents desiccation; allows drainage |
Adherent: wet-to-dry (debridement); Non-adherent: Telfa (granulation) |
| Secondary |
Absorbs exudate; provides padding; decreases dead space |
Cast padding, roll cotton, gauze rolls |
| Tertiary (Outer) |
Holds layers in place; compression; protection |
Elasticon, Vetrap, conforming bandage |
Factors Affecting Wound Healing
Local Factors
- Infection: Most common cause of delayed healing; greater than 10^5 organisms/gram impairs healing
- Foreign material/necrotic tissue: Perpetuates inflammation; substrate for bacteria
- Motion: Disrupts capillary buds; increases collagen deposition
- Dead space: Allows seroma; increases infection risk
- Poor blood supply: Distal extremities heal slowly; exposed bone inhibits healing
Systemic Factors
- Malnutrition: Hypoproteinemia (less than 2 g/dL) delays healing
- Anemia: Decreases tissue oxygen; impairs fibroblast function
- Obesity: Decreased vascularity; poor suture holding
- Medications: Corticosteroids inhibit all phases of healing
| Drug |
Dose (Dogs) |
Indications |
| Amoxicillin-Clavulanate |
12.5-25 mg/kg PO q12h |
First-line for skin/soft tissue and bite wounds; covers Staph, Strep, Pasteurella, anaerobes |
| Cephalexin |
22-30 mg/kg PO q8-12h |
First-generation cephalosporin; good empirical choice; covers Staph/Strep |
| Ampicillin-Sulbactam |
30 mg/kg IV q8h |
Hospitalized patients; severe bite wounds; IV therapy |