High Prevalence of Biofilm on Retrieved Implants from Aseptic Pseudarthrosis Cases Article (Faculty180)

cited authors

  • Agarwal, Aakash; Mooney, Megan; Agarwal, Ashish; Jayaswal, Daksh; Saakyan, Gayane; Goel, Vijay; Wang, Jeffrey; Anand, Neel; Garfin, Steve; Shendge, Vithal B; Elgafy, Hossein K

description

  • Abstract Introduction: Recent literature has associated pseudarthrosis and pedicle screw loosening with subchronic infection at the pedicle of the vertebra. Positive culture results from previous retrieval analysis has shown a high frequency of bacterial contaminant in such patients. The objective of the current study is to visually capture the architecture of these undiagnosed infections, which have been described in other studies as biofilm on the supposedly “aseptic” screw loosening. Methods: Explants from 10 consecutive patients undergoing revision spine surgery for pseudarthrosis were collected and fixed in glutaraldehyde solution. Each of these implants were then imaged thoroughly using scanning electron microscopy and X-ray spectroscopy to evaluate the architecture of the biofilm. Additionally, in 8 of the patients swabs from tissues around the implants were sent for cultures, to assess bacterial infiltration in tissues beyond the biofilm. The implants were also analyzed using energy dispersive X-ray spectroscopy. Exclusion criteria: Clinically diagnosed infection (current or previous), and/or mechanical failure of implant due to falls/accidents. Results: The study was successful in capturing the visual architecture of the biofilm on retrieved implants. 77% of pseudarthrosis cases presented with loose pedicle screws diagnosed with preoperative computed tomography (CT) scan showing radiolucency along the screw track and confirmed intraoperatively. 72% of the cases showed biofilm on explants. Conclusions: In absence of clinical presentation of infection, impregnated bacteria could form biofilm around an implant which remains undetected via contemporary diagnostic methods, including swabbing. Implant-biofilm is frequently present in “aseptic” pseudarthrosis cases. Key words: Pseudarthrosis; screw loosening; biofilm; occult infection; undiagnosed infection; sub-chronic infection; surgical site infection; aseptic revision; readmission

authors

publication date

  • 2020

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