Safety and Efficacy of Vancomycin-Gentamicin PMMA Bead Pouch Therapy in the Management of Pyogenic Soft Tissue Infections of the Extremities: A Case Series of 19 Patients.

Objective

The aim of this case series was to investigate the safety and efficacy of vancomycin-gentamicin embedded PMMA beads (VGPB) in the setting of acute pyogenic soft tissue infections (STIs) of the extremities. Materials and

Methods

A retrospective study of 19 cases diagnosed with pyogenic STIs of the lower or upper extremity in two academic institutions was conducted between January 2017 and December 2023. All patients underwent surgical debridement, systemic antibiotics and intrawound deposition of vancomycin and gentamicin embedded cement beads (2 g of vancomycin plus 1 g of gentamicin diluted in 40 g of PMMA). Upon second look (4th-7th day post-index surgery) the cement beads were removed, serum samples from the surgical site of infection and from peripheral blood were obtained and the concentration of eluted vancomycin and gentamicin was measured. Furthermore, the white blood cell count (WBC), C reactive protein serum levels (CRP) and erythrocyte sedimentation rate (ESR) were measured before the surgical debridement and after the end of the bead therapy. All patients were reevaluated after discharge with a mean follow-up of 4.4 years (range, 1 to 7.6).

Results

Wound vancomycin and gentamicin levels were significantly higher than those measured in the serum (34.01 ± 4.47 μg/mL versus 11.96 ± 2.79 μg/mL, p < 0.001 and 5.75 ± 1.22 μg/mL versus 0.51 ± 0.14 μg/mL, p < 0.001 respectively). Serum vancomycin and gentamicin concentrations were below the level of toxicity and no adverse events related to antibiotic-embedded bead treatment were documented. Serum WBC, ESR and CRP levels before debridement (13,446 ± 935.7 c/μL, 42.3 ± 18.7 mm/h and 113.9 ± 20.26 mg/L respectively) were significantly higher than those after the end of treatment (7889 ± 1203.6 c/μL, p < 0.001; 30.3 ± 9.14 mm/h, p = 0.017; and 22.7 ± 6.68 mg/L, p < 0.001 respectively). Two cases (10.5%) had a local recurrence of their STIs. Both of them relapsed within 4 months after their treatment and both had Gram-negative pathogens.

Conclusions

Vancomycin-gentamicin PMMA bead pouch therapy appears to be a safe and effective adjuvant treatment for pyogenic soft tissue infections, offering high local antibiotic availability without systemic adverse effects.