The therapeutic benefit of allopurinol in the treatment of foreign body granulomas caused by polymethylmethacrylate microspheres

In vitro elution characteristics of antibiotic-loaded polymethylmethacrylate cement and a calcium sulfate bone substitute using staphylococci isolated from orthopedic implant-associated infections

Polymethylmethacrylate (PMMA) remains the gold standard antibiotic carrier in the management of osteomyelitis. However, biodegradable ceramic carriers may exhibit more efficient antibiotic elution properties. Through zone of inhibition (ZOI) testing and biofilm killing assays, we assessed the in vitro elution efficacy of vancomycin released from calcium sulfate (PG-CSH) and PMMA beads as carriers on clinical strains of Staphylococcus aureus and Staphylococcus epidermidis, which were isolated from sonication fluid of orthopedic implant-associated infections. Overall, vancomycin-loaded PMMA and PG-CSH beads showed potency (ZOI above 4 cm² ) for up to 14 days against ATCC and clinical strains. Vancomycin-loaded PG-CSH beads displayed higher rates, exhibited a more stable antibiotic elution, had greater impacts on bacterial colony-forming unit counts and produced higher ZOIs; additionally, statistically significant differences (Student's t test) were observed in different time sets during the experiment. In the biofilm killing assay, PG-CSH loaded with vancomycin resulted in more bacterial deaths. In conclusion, in the present study, both PG-CSH and PMMA beads acted as good carriers, but greater antimicrobial elution and biofilm bacterial killing were observed with PG-CSH than PMMA. Future in vitro research should focus on testing other difficult-to-treat clinical strains, including multidrug resistant coagulase-negative staphylococci and Gram-negative bacilli.

Foreign body granulomas after the use of dermal fillers: pathophysiology, clinical appearance, histologic features, and treatment

A foreign body granuloma is a non-allergic chronic inflammatory reaction that is mainly composed of multinucleated giant cells. Foreign body granulomas may occur after the administration of any dermal filler. Factors such as the volume of the injection, impurities present in the fillers, and the physical properties of fillers affect granuloma formation. The formation of granulomas involves five phases: protein adsorption, macrophage adhesion, macrophage fusion, and crosstalk. The clinical and pathologic features of granulomas vary depending on the type of filler that causes them. Foreign body granulomas can be treated effectively with intralesional corticosteroid injections. Surgical excisions of granulomas tend to be incomplete because granulomas have ill-defined borders and moreover, surgical excisions may leave scars and deformities.