What are the best skin substitute grafts for bone coverage?

Best Skin Substitute Grafts for Bone Coverage

Based on the most recent evidence, standard skin substitutes are not recommended as routine treatment for bone coverage, but Integra® dermal regeneration template can be effectively used directly on exposed bone without requiring additional skin grafting.

Understanding Skin Substitutes for Bone Coverage

Skin substitutes are categorized into three main types:

1. Cellular skin substitutes: Products containing living cells (fibroblasts, keratinocytes)
2. Acellular skin substitutes: Products where cells have been removed, leaving only the structural matrix
3. Autologous skin substitutes: Products derived from the patient's own tissues

Evidence-Based Recommendations

The 2024 International Working Group on the Diabetic Foot (IWGDF) guidelines provide important insights on skin substitutes, though they focus primarily on diabetic foot ulcers 1:

• Cellular skin substitutes: Not recommended as routine adjunct therapy (Conditional recommendation; Low evidence)
• Acellular skin substitutes: Not recommended as routine adjunct therapy (Conditional recommendation; Low evidence)
• Autologous skin substitutes: Not recommended (Strong recommendation; Low evidence)

Integra® for Bone Coverage

Despite the general recommendations against routine use of skin substitutes, specific evidence supports the use of Integra® dermal regeneration template directly on bone:

Key Benefits of Integra® for Bone Coverage:

• Direct application to avascular tissue: Recent 2024 research demonstrates successful use directly on bone and cartilage without requiring additional skin grafting 2
• Effective for complex soft-tissue defects: Seven years of experience shows Integra® is particularly useful for managing complex soft-tissue loss and threatened extremities with tendon, joint, or bone exposure 3
• Multi-layer application: Can be stacked in multiple layers to fill significant volume loss 3
• Bone protection: Permits salvage of threatened extremities by protecting exposed tendons, bones, and joints 3
• Complete healing: A 2024 study of 17 patients with defects down to bone or cartilage showed complete healing when Integra® was placed directly on these avascular structures 2

Application Technique for Bone Coverage:

1. Place the collagenous dermal layer of Integra® directly onto the exposed bone
2. Secure with absorbable sutures and bolster dressing
3. Keep the wound dry for 14 days
4. Remove the silicone layer and dressing after 14 days
5. Continue regular wound care

Clinical Considerations and Pitfalls

Advantages:

• Immediate availability
• Available in large quantities
• Relatively simple and reliable technique
• Pliable with good cosmetic outcomes 4
• Can be applied directly to bony surfaces like patella 5
• Patients generally experience less pain during the maturation phase 3

Potential Complications:

• Risk of infection under the silicone layer
• Silicone detachment
• Potential recurrence of contraction 4
• Epithelial autografts on multilayer Integra® applications may initially "ghost" (auto-digest to dispersed cells) before reappearing as a confluent epithelial layer 3

Monitoring:

• Infections are readily visible and early recognition allows for treatment of circumscribed areas without jeopardizing the entire wound 3
• Expect longer lengths of stay but not significantly greater than with traditional techniques 3

Alternative Approaches

For cases where standard Integra® application may not be optimal, a one-step meshed composite skin graft (MCSG) procedure has been developed:

1. Remove the silicon layer of Integra®
2. Mesh the dermal analogue (1:1.5)
3. Expand and place on the wound
4. Cover with a meshed split thickness autograft
5. Apply appropriate dressing 6

This approach can accelerate wound closure by 6-19 days compared to the traditional two-step procedure 6.