Vacuum-assisted closure (V.A.C. Therapy) uses 2 distinct types of foams, with different physical characteristics: the black polyurethane (PU) foam and the white polyvinyl alcohol (PVA) foam. This prospective, randomized study evaluates the response of cutaneous blood flow (CBF) in healthy intact forearm skin to varying V.A.C. Therapy negative pressures and both foam types. Continuous negative pressure was used in the range of 25-500 mmHg. Skin blood flow was measured with noninvasive laser Doppler probes incorporated into the foam. Significant increase in CBF was found with both foams up to negative pressure of 300 mmHg, with over 5-fold increase (mean: 5.57; SD: 3.32) with the PU foam and nearly 3-fold increase (mean: 2.87; SD: 1.29) with the PVA foam. Comparison of blood flow at baseline and at a negative pressure of 300 mmHg showed a statistically significant difference (P< 0.001). No decrease in blood flow below baseline was observed during the experiments.

In a retrospective, case-control cohort study an assessment was made of the clinical outcome of patients with osteomyelitis treated with a new modality of negative pressure wound therapy, so called negative pressure instillation therapy. In this approach, after surgical debridement, a site of osteomyelitis is treated with negative pressure of at least 300 mmHg applied through polyvinyl alcohol dressing. The polyvinyl alcohol foam is irrigated through the tubes three times a day with a polyhexanide antiseptic solution. In 30 patients (14 males; mean age 52 [range, 26-81]) admitted between 1999 and 2003 with osteomyelitis of the pelvis or lower extremity, we assessed time to wound closure, number of surgical procedures and rate of recurrence of infection as well as need for rehospitalizations. For comparison, a control group of 94 patients (males, 58; mean age 47 [range, 9-85]), matched for site and severity of osteomyelitis, was identified in hospital records between 1982 and 2002. These patients underwent standard surgical debridement, implantation of gentamicin polymethylmethacrylate beads and long-term intravenous antibiotics. In the Instillation group the rate of recurrence of infection was 3/30 (10%), whereas 55/93 (58.5%) of the controls had a recurrence (p<0.0001). Moreover, in those treated with instillation the total duration of hospital stay was shorter and number of surgical procedures smaller as compared with the controls (all p<0.0001). We conclude that in posttraumatic osteomyelitis negative pressure instillation therapy reduces the need for repeated surgical interventions in comparison with the present standard approach.

Maggot ES are differentially effective against biofilms of S. aureus and P. aeruginosa.

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