Gentamicin Sponge for Anti-infection, a Controversial Old Topic and Preliminary Exploration of the Solution, in Vitro and in Vivo Experiments

Purpose: Our study was to construct drug-loading and drug-release quantitative equation of gentamicin sponge, in addition, obtain the wound infection prevented and treated scheme of gentamicin sponge. Methods: Sterile sponge was cut into 1×1×0.5cm size and immersed into 40mg/ml, 16mg/ml, 8mg/ml, 4mg/ml, 1.6mg/ml, 0.8mg/ml or 0mg/ml gentamicin solution for 12h, 24h, 48h, 96h or 120h to evaluate gentamicin-loading of sponge. Sponge was immersed in gentamicin solution of different concentrations for 48h and then air-dried. Air-dried sponge was immersed into 10ml 0.9% physiological saline to evaluated gentamicin-release. Staphylococcus aureus (MSSA) and Pseudomonas aeruginosa (P. aeruginosa) were used to explore infection prevented scheme of gentamicin sponge. Besides, femur fractured with wound infection rat model was used to discuss the infection treated scheme.Results: The equation of gentamicin-loading of sponge was: z=(0.03718±0.01672)x+(-4.578e-4±0.06253)y+(-2.50935e-4±1.47521e-4)x2+(0.00303±0.00149)y2+(0.00408±3.52827e-4)xy (R2 was 0.97) and drug-release equation was z=(4.37205±1.18048)x+(-7.05921±3.09628)y+(-0.04596±0.01287)x2+(0.3309±0.07912)y2+(0.31559±0.02754)xy (R2 was 0.95). The antibacterial zone sizes of sponges immersed in 40mg/ml, 16mg/ml, 8mg/ml, 4mg/ml, 1.6mg/ml, 0.8mg/ml gentamicin solution were larger than 0mg/ml air-dried sponge, and the difference had statistically significant (p<0.01). Rats of groups of 40mg/ml air-dried sponge, 16mg/ml air-dried sponge, 8mg/ml air-dried sponge had no wound suppuration in both MSSA and P. aeruginosa infection rat model.Conclusions: The quantified equation of gentamicin-loading and release of sponge was with high accuracy. 1.6 mg/ml air-dried sponge and 0.8mg/ml air-dried sponge were enough to prevent wound infection. Besides, if wound were confirmed to be sensitive bacteria infected, we recommended to use 40mg/ml air-dried sponge, 16mg/ml air-dried sponge or 8mg/ml air-dried sponge to treat.

Comparison of Bone Preserving and Radical Surgical Treatment in 32 Cases of Calcaneal Osteomyelitis

Introduction. Radical procedures like calcanectomy and amputation performed for calcaneal osteomyelitis are regarded as effective in eradication of infection even though potentially functionally disabling. Bone sparing procedures offer better functional result at the expense of potentially worse infection control. The aim of the study has been to assess the influence of the surgical radicalism as much as the extent of bone infection on the final outcome in the surgical therapy of chronic calcaneal osteomyelitis (CO). Material and method. 32 patients with chronic CO have comprised the group under study: 8 with superficial type, 12 localised type and 12 with diffuse type according to Cierny-Mader classification. The aim of the treatment was to heal infection, preserve the heel shape and achieve good skin coverage over the calcaneus. The therapy consisted of 9 debridement surgeries with or without flaps, 8 drilling-operations of the calcaneus with application of collagen-gentamicin-sponge in bore holes, 15 partial and 2 total calcanectomies, and 4 below-the knee amputations. Results. The healing of infection and wound has been achieved after 7 of 9 debridements, 6 of 8 drilling-operations, 13 of 15 partial and all total calcanectomies. Conclusion. Bone preserving operations in chronic calcaneal osteomyelitis provided inferior infection control (76,47% vs 88,24%) and worse patient satisfaction (88,24% vs 100%) and almost camparable ambulation (100% vs 93,33%). Drilling of the calcaneus with application of collagen sponge containing gentamicin performed in chronic diffuse calcaneal osteomyelitis seems to offer a viable alternative to partial or radical calcanectomy. Level of evidence: V.