What is the difference between Negative Pressure Wound Therapy (NPWT, vacuum-assisted closure) and conventional bolster dressings on split-thickness skin grafts (SSGs)?

Negative Pressure Wound Therapy vs. Conventional Bolster Dressings on Split-Thickness Skin Grafts

Definitions

Negative Pressure Wound Therapy (NPWT)

NPWT is a technique that applies controlled subatmospheric pressure (typically 75-125 mm Hg) through a sealed dressing system over a split-thickness skin graft to promote adherence, improve microcirculation, and enhance graft take. 1, 2

• The system consists of a foam or gauze interface placed over the graft, covered with an occlusive adhesive dressing, and connected to a vacuum source that maintains continuous or intermittent negative pressure 1, 3
• The negative pressure creates tight adhesion between the graft and recipient bed while removing excess fluid and hematoma that could compromise graft survival 4, 5
• Standard pressure settings range from 75-125 mm Hg, with lower pressures (75 mm Hg) associated with reduced pain while maintaining efficacy 3
• The dressing typically remains in place for 4-5 days postoperatively before the first assessment 1, 2

Conventional Bolster Dressings

Conventional bolster dressings (also called tie-over dressings) consist of non-adherent gauze (such as Vaseline gauze) layered with cotton pads, secured with sutures tied over the graft to provide compression and immobilization. 2, 5

• These dressings rely on mechanical pressure from the bolster material to maintain graft-bed contact 5
• They require manual compression without active fluid evacuation, making them dependent on proper technique and patient immobility 2
• Dressing changes are typically performed every 2-3 days, requiring multiple manipulations of the graft site 4
• The average time to complete healing with conventional dressings is 9-11 days with 3-4 dressing changes needed 4, 2

Key Performance Differences

Graft Take Rates

• NPWT achieves superior graft take rates of 96-98% compared to 84-88% with conventional bolster dressings 1, 4, 2
• NPWT significantly reduces the need for repeat skin grafting (3% vs 19% failure rate) 5

Healing Time

• NPWT reduces mean healing time to 6-8 days versus 9-11 days with conventional dressings 4, 2
• Fewer dressing changes are required with NPWT (typically one assessment at day 4-5) compared to multiple changes with bolster dressings 4, 2

Clinical Advantages of NPWT

• Particularly beneficial when wound bed conditions are less-than-ideal or in patients with comorbidities 3, 2
• Provides consistent, controlled pressure regardless of patient movement 5
• Can be assembled using low-cost materials (gauze and wall suction) with comparable results to commercial systems 1