What is secondary suturing for a patient with a contaminated wound and underlying conditions such as diabetes or vascular disease?

What is Secondary Suturing?

Secondary suturing (also called delayed primary closure) is a wound closure technique where the wound is left open for 2-5 days to allow granulation tissue development and bacterial load reduction, then mechanically closed with sutures or approximation devices before complete epithelialization occurs. 1, 2

Mechanism and Physiologic Rationale

Secondary suturing works through several key mechanisms that distinguish it from immediate primary closure:

• Enhanced wound oxygenation and blood supply develop through angiogenesis in the forming granulation tissue, which potentiates local wound resistance 1, 2
• Bacterial inoculum reduction occurs through open wound management with proper dressing changes, decreasing infection risk 1, 2
• Superior mechanical strength results from higher partial pressure of oxygen, increased blood flow, and enhanced collagen synthesis and remodeling activity in wounds managed with delayed closure 2
• Vascularized granulation tissue provides better wound bed preparation, improving wound strength and collagen content compared to immediate closure 1

Optimal Timing

The American College of Surgeons recommends performing delayed primary closure by suturing the wound 2-5 days postoperatively after allowing granulation tissue to develop 1, 3. One effective protocol involves:

• Four days of open wound management with Xeroform gauze between skin and subcutaneous tissue 3
• Removal of dressing on day 5 followed by skin approximation with Steri-Strips 3
• Daily wound inspection, irrigation, and dressing changes with saline or betadine soaks until closure 2

Specific Indications for Contaminated Wounds

High-Risk Patient Populations

For contaminated or dirty wounds, delayed primary closure should be applied when patients have:

• Diabetes mellitus - a clear indication for delayed closure in contaminated wounds 1, 3
• Vascular disease - specifically recommended by the World Society of Emergency Surgery for high-risk patients 1
• Age >60 years in the setting of clean-contaminated wounds 3
• Malnutrition or obesity as additional risk factors 3
• Purulent contamination - particularly in high-risk patients 1

Wound Characteristics Requiring Delayed Closure

• All contaminated and infected wounds are best managed with delayed primary closure when possible, or healing by secondary intention if closure is not feasible 3
• Heavily contaminated wounds that cannot be adequately debrided may require delayed closure to reduce infection risk 1
• Complicated appendectomies with contaminated/dirty wounds 1, 2
• Post-cardiac surgery sternal wound dehiscence - one of the clearest indications 2
• Complicated abdominal wall reconstructions in contaminated settings 2

Critical Distinction: When NOT to Use Delayed Closure

Recent high-quality evidence challenges routine use of delayed primary closure. A multicenter randomized controlled trial found that superficial surgical site infection rates were actually lower with primary closure (7.3%) compared to delayed primary closure (10%) in complicated appendicitis, though this difference was not statistically significant 4, 1. Additionally:

• Primary closure costs $2,083 less per case than delayed primary closure 1
• Hospital stay and recovery times are longer with delayed closure 4, 1
• No significant difference in infection rates was found in some high-quality RCTs, with meta-analysis benefits disappearing when using random-effects modeling due to high heterogeneity 1, 2

Practical Algorithm for Decision-Making

For contaminated wounds in patients with diabetes or vascular disease:

1. Assess wound contamination level - clean-contaminated vs. contaminated vs. dirty 1
2. Evaluate tissue viability and extent of debridement needed 1
3. Identify high-risk factors: diabetes, vascular disease, age >60, purulent contamination 1, 3

If ≥2 high-risk factors present with contaminated/dirty wound:

• Consider delayed primary closure 1, 3
• Plan for wound revision between days 2-5 1
• Use daily saline/betadine soaks with dressing changes 2

If clean-contaminated wound with adequate debridement:

• Proceed with primary closure using absorbable intradermal suture - this reduces complications (surgical site infection, abscess, seroma) and costs compared to delayed closure 4, 1

Special Considerations for Bite Wounds

Infected bite wounds should NOT be closed primarily. 4 For bite wounds:

• Early suturing (<8 hours after injury) is controversial with no definitive studies 4
• Approximation of wound margins with Steri-Strips followed by delayed primary or secondary intention closure is prudent 4
• Facial wounds are an exception and can be closed primarily by a plastic surgeon if meticulous wound care, copious irrigation, and prophylactic antibiotics are provided 4

Common Pitfalls to Avoid

• Do not delay necessary debridement while waiting for the delayed closure window - remove necrotic infected material immediately 4
• Do not use delayed closure routinely without considering patient-specific factors and wound characteristics, as it increases costs and hospital stay without clear benefit in many cases 1
• Ensure adequate vascular supply before any closure attempt - revascularization should occur early (within 1-2 days) for severely infected ischemic feet rather than relying on prolonged antibiotic therapy 4
• Do not close wounds under excessive tension - significant tissue loss or devitalization contraindicates primary closure regardless of timing 1