High Prevalence of Biofilms on Retrieved Implants from Aseptic Pseudarthrosis Cases

Abstract

Introduction Recent literature has associated pseudarthrosis and pedicle screw loosening with subchronic infection at the pedicle of the vertebra. The positive culture results of a previous retrieval analysis show that such patients have a high frequency of bacterial contamination. The objective of this study is to visually capture the architecture of these undiagnosed infections, which have been described in other studies as biofilms on 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 was imaged thoroughly by using scanning electron microscopy and x-ray spectroscopy to evaluate the architecture of the biofilm. Additionally, eight patient 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. The exclusion criteria included clinically diagnosed infection (current or previous) and/or mechanical failure of the implant due to falls/accidents. Results The study was successful in capturing the visual architecture of the biofilm on retrieved implants. A total of 77% of pseudarthrosis cases presented with loose pedicle screws, which were diagnosed by a preoperative computed tomography scan showing radiolucency along the screw track and were confirmed intraoperatively, and 72% of the cases showed biofilm on explants. Conclusions In the absence of the clinical presentation of infection, impregnated bacteria could form a biofilm around an implant, and this biofilm can remain undetected via contemporary diagnostic methods, including swabbing. Implant biofilm is frequently present in “aseptic” pseudarthrosis cases.

Bacterial Biofilm And Role In The Pathogenesis Of Disease

“…The patients with biofilms were shown to have been denuded of cilia and goblet cells, unlike the controls without biofilms who had normal cilia and goblet cell morphology. [27] Biofilms were also found on samples from two of 10 healthy controls mentioned. The species of bacteria from intraoperative cultures did not correspond to the bacteria species in the biofilm on the respective patient's tissue.…”

Implantatversagen aufgrund von Infekt/Low-grade Infekt – Ursachen und Behandlungskonzepte

“…Diese Arbeiten zeigen, dass in 39-65% der gelockerten Wirbelsäulenimplantate eine Infektion nachweisbar ist und diese als Ursache der Lockerung zu werten ist. Eine elektronenmikroskopische Analyse der entfernten Implantate von 10 Patienten mit Pseudarthrosen der Wirbelsäule konnte in 72% einen bakteriellen Biofilm auf der Implantatoberfläche nachweisen, sodass eine bakterielle Kontamination der Sonikate auszuschließen ist [34].…”