A new study, published in the journal Spine Surgery and Related Research, is the first to visually capture the structure of biofilm on retrieved implants from patients who underwent spine surgery for pseudarthrosis.
Previous studies in this area are significant, numerous researchers around the world have shown evidence regarding higher prevalence of positive microbial cultures in revision spine surgeries. Many of these researchers, especially those more recently, also reported higher correlation of these positive microbial cultures with pseudarthrosis, or screw loosening. Past authors have reported occult infection and chronic impact infection.
However, none were able to visually capture the biofilm architecture in such “aseptic” patient population undergoing revision spine surgery. Thereby, in absence of visual evidence, the concern of sample contamination and having false positive in culture method is common.
This study is the first to demonstrate presence of biofilm on implants from failed spine surgery via visual means, supporting previous studies conducted by researchers showing positive culture.
This study brings to light that biofilm is a real problem with serious consequences such as delayed or late onset infection or pseudarthrosis. These chronically infected implants cannot be treated without removal of the implant, as the biofilm protects the bacteria against antibiotics.
Of the ten pedicle screw implants included in the study from ten consecutive revision surgeries, 72% of them showed signs of biofilm when removed. Images were taken of the biofilm using electron microscopy, creating high resolution images.
In samples where biofilms were identified, an energy dispersive x-ray spectroscopy was performed to identify the regional distribution of mineralization.
The original aim of this study had been not only to visually capture bio film on these implants, but also to characterise supposedly aseptic pedicle screw loosening in patients undergoing revision surgery.
While the study did show a positive correlation between screw loosening and biofilm being present, unlike past studies, these results could not achieve statistically significance due to lower sample size, which the authors cited in their limitations.