What is skin graft fixation?

Skin Graft Fixation: Methods and Evidence-Based Approaches

Skin graft fixation refers to the techniques used to secure a skin graft to the recipient wound bed to prevent displacement and optimize graft take, with negative pressure wound therapy (NPWT) showing the strongest evidence for enhancing graft survival compared to traditional methods.

Understanding Skin Graft Fixation

Skin graft fixation is a critical step in the skin grafting process that ensures:

1. Prevention of shearing forces that could displace the graft
2. Elimination of fluid collections (seroma and hematoma) between the graft and wound bed
3. Maximization of contact between the graft and the recipient site
4. Promotion of revascularization and graft take

Primary Fixation Methods

1. Traditional Tie-Over Bolster Technique

• Involves suturing the graft to wound edges and applying pressure with gauze/cotton secured by sutures
• Creates even pressure distribution across the graft surface
• No significant difference in graft take compared to simpler methods 1

2. Non-Bolster Methods

• Simple dressings that provide light pressure without complex tie-over arrangements
• Similar efficacy to tie-over bolsters in multiple studies 1
• May be preferred in anatomically simple areas

3. Adhesive Glues

• Fibrin sealants and other tissue adhesives used to secure grafts
• No demonstrated improvement in graft take over traditional methods 1
• May reduce operative time but add material costs

4. Negative Pressure Wound Therapy (NPWT)

• Most effective method with strongest evidence for enhancing graft take 2, 1
• Applies continuous or intermittent negative pressure to the wound via specialized dressing
• Recommended for bolstering split skin grafts in abdominal wounds (Grade B recommendation) 2
• Mechanisms of action include:
  • Extraction of wound exudate
  • Stimulation of granulation tissue formation
  • Wound contraction
  • Improved tissue perfusion
  • Enhanced graft-to-wound bed contact 2

Clinical Applications and Considerations

In Open Abdominal Wounds

NPWT is particularly valuable in complex wounds such as grade 4 open abdominal wounds ("frozen abdomen") where:

• It promotes granulation tissue formation creating a suitable surface for grafting 2
• It significantly enhances split skin graft take when used as a bolster 2
• It helps manage wound exudate while securing the graft 2

In Diabetic Foot Ulcers

• NPWT has shown benefit in post-surgical wounds including improved split skin graft take 2
• However, studies on diabetic foot ulcers had methodological limitations 2

Pitfalls and Caveats

1. NPWT-specific considerations:

   • Requires specialized equipment and training
   • Potential adverse effects include wound maceration, retention of dressings, and wound infection 2
   • Contraindicated in certain wound types (exposed vessels, untreated osteomyelitis)
   • Requires careful interface management to prevent granulation tissue ingrowth into foam 2

2. General graft fixation considerations:

   • Fixation method should be selected based on:
     • Anatomical location (contoured vs flat surfaces)
     • Wound bed characteristics (vascularity, exudate level)
     • Graft type (split-thickness vs full-thickness)
   • Inadequate fixation can lead to graft failure through:
     • Seroma/hematoma formation
     • Shearing forces displacing the graft
     • Insufficient contact with the wound bed

Evidence Quality Assessment

The evidence supporting NPWT for skin graft fixation is the strongest among all methods:

• Multiple randomized controlled trials show enhanced graft take with NPWT 1
• Grade B recommendation for NPWT to enhance split skin graft take in abdominal wounds 2
• Other methods (tie-over bolsters, adhesives) show no significant difference in outcomes 1

However, there remains a scarcity of high-quality, low-bias studies directly comparing all fixation methods across different wound types 1, with only one of 13 RCTs deemed to have low risk of bias.