Objective Mesh infection may occur after incisional hernia repair using prosthetic mesh. Preparation of antibiotics-bonded meshes to prevent infection is one of the solutions. To evaluate the anti-infection effect of polypropylene mesh bonded norvancomycin slow-release microsphere by preparing the rat model of incisional hernia repair contaminatedwith Staphylococcus aureus. Methods The norvancomycin slow-release microspheres were prepared by emulsion and solvent evaporation method and they were bonded to polypropylene mesh (50 mg/mesh). The appearance of the microspheres was observed using scanning electronic microscope (SEM). The content of norvancomycin in microspheres and the release rate of the norvancomycin in norvancomycin-bonded polypropylene mesh were detected using high performance l iquid chromatography method. The rat models of incisional hernia were developed in 40 healthy Sprague Dawley rats, aged 10-11 weeks and weighing 200-250 g. The rats were divided randomly into the experimental group (norvancomycin-bonded polypropylene mesh repair, n=20) and the control group (polypropylene mesh repair, n=20). And then the mesh was contaminated with Staphylococcus aureus. The wound heal ing was observed after operation. At 3 weeks after operation, the mesh and the tissue around the mesh were harvested to perform histological observation and to classify the inflammatory reaction degree. Results The norvancomycin microsphere had integrated appearance and smooth surface with uniform particle diameter, 64% of particlediameter at 60 to 100 μm, and the loading-capacity of norvancomycin was 19.79%. The norvancomycin-bonded polypropylene patch had well-distributed surface and the loading-capacity of norvancomycin was (7.90 ± 0.85) mg/cm2. The release time of norvancomycin in vitro could last above 28 days and the accumulative release rate was 72.6%. The rats of 2 groups all survived to experiment completion. Wound infection occurred in 2 rats of the experimental group (10%) and 20 rats of the control group (100%), showing significant difference (χ2=32.727 3, P=0.000 0). The inflammatory reaction in experimental group was not obvious, grade I in 16 rats and grade II in 4 rats, and numerous inflammatory cell infiltration occurred in the control group, grade II in 3 rats and grade III in 17 rats, showing significant difference (Z=32.314, P=0.000). Conclusion The polypropylene mesh bonded norvancomycin slow-release microsphere has definite anti-infection effect in rat model of incisional hernia repair contaminated by Staphylococcus aureus.
With silk fibroin and vancomycin (VCM) as carrier and drug model, respectively, we prepared silk fibroin microspheres (SFM) with different concentration using the water-in-oil emulsion solvent diffusion method. We further developed VCM loaded calcium sulfate hemihydrates (CSH)/SFM artificial bone composites. In this study, surface morphology of the materials was observed using scanning electron microscope (SEM). Structure of the materials was studied with Fourier transform infrared spectroscopy (FTIR). Antibacterial activity of the materials was validated with the inhibition zone test. Drug release property of materials was evaluated using ultraviolet/visible spectrophotometry. Mechanical property of the materials was tested using computer-controlled electronic universal testing machine. The results showed that silk fibroin concentration had no significant effect on molecular conformation and antibacterial property of the SFM. The average diameter of SFM increased and the release rate decreased gradually as the silk fibroin concentration increased. The release rate decreased and the compressive fracture work increased as the silk fibroin concentration increased when adding SFM to CSH. This composite had partly corrected the disadvantages of CSH including the high brittleness and initial burst release. The research would have a good application foreground in the clinical treatment of infectious bone defect.
ObjectiveTo investigate the effectiveness of modified tibial transverse bone transport technique combined with vancomycin calcium phosphate bone cement local filling and covering in the treatment of diabetic foot (DF). MethodsThe clinical data of 22 DF patients treated with modified tibial transverse bone transport technique combined with vancomycin calcium phosphate bone cement local filling and covering between October 2019 and December 2021 were retrospectively analyzed. There were 13 males and 9 females with an average age of 61.3 years (range, 41-74 years). The duration of diabetes mellitus was 8-30 years, with an average of 12.5 years, and the duration of DF was 10-42 days, with an average of 28.2 days. There were 2 cases of grade 3 and 20 cases of grade 4 according to Wagner classification. CT angiography was performed on both lower extremities of the patients, and the blood vessels of the affected extremities were narrowed to varying degrees and the blood supply was poor. The preoperative skin temperature of affected foot was (28.27±0.91)°C, the ankle brachial index (ABI) was 0.42±0.11, and the visual analogue scale (VAS) score was 7.7±0.6. Preoperative size of DF ulcer ranged from 2.5 cm×2.0 cm to 3.5 cm×3.0 cm. The skin temperature of affected foot, ABI, VAS score, and skin wound healing of the affected foot were recorded and compared between before operation and at 3 months after operation. ResultsAll patients were followed up 3-18 months, with an average of 10.5 months. The infection of 1 patient with Wagner grade 4 did not improve significantly after operation, and there was a trend of further deterioration, and the amputation of the left leg was finally performed at 22 days after operation.The remaining 21 patients recovered well after operation, the external fixator was removed at 1 month after operation, the wound healed at 3 months after operation, and there was no recurrence of ulcer in situ or other sites during follow-up. At 3 months after operation, the skin temperature of affected foot was (31.76±0.34)°C, the ABI was 0.94±0.08, and the VAS score was 2.1±0.3, which significantly improved when compared with those before operation (t=25.060, P<0.001; t=32.412, P<0.001; t=–51.746, P<0.001). ConclusionModified tibial transverse bone transport technique combined with vancomycin calcium phosphate bone cement local filling and covering for DF patients can effectively improve the blood supply of the affected limb, promote wound healing, and improve effectiveness.