A scanning electron microscope characterisation of biofilm on failed craniofacial osteosynthesis miniplates

Between 3 and 18% of craniofacial osteosynthesis plates are removed due to chronic infection. Removal of the plate is necessary to manage the chronic infective state i.e. miniplate removal results in resolution of the infection. These observations are suggestive of a biofilm-related infection. The aim of this retrospective study was to characterise the presence of biofilm on the removed miniplates from oral and maxillofacial surgery.

A total of 12 plates and associated screws were recovered from eleven patients suffering from persistent, trauma site infection. The recovered plates plus 1 control plate were imaged using scanning electron microscopy (SEM). One recovered plate was also imaged using confocal microscopy (CM) for comparative purposes.

Of the 12 plates, 3 (25%) demonstrated highly localised polymicrobial biofilms, five (42%) demonstrated coccal biofilms, one possessed a filamentous biofilm and one showed attached yeast. Overall, 75% of the plates and 82% of the patients exhibited evidence of biofilm to varying degrees. All of the infections resolved following removal of the plates and antibiotic treatment.

Microbial biofilms can explain the clinical course of chronic infections associated with miniplates.