Article
Presence of bacteria in healthy spinal bone meal collected during instrumentation – Colonisation or evidence for future low-grade infection?
Nachweis von niedrig-virulenten Bakterien in gesundem Knochenmehl: Besiedlung oder pathogen?
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Published: | May 25, 2022 |
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Objective: Cutibacterium acnes is suspected to cause low grade infections and screw loosening after dorsal instrumentation and gains more and more interest for its role in spine pathology. While C. acnes belongs to the standard skin flora, its pathogenic role remains a question of debate.
Methods: We prospectively enrolled patients undergoing spinal instrumentation for trauma or degenerative indications. Patients suffering from previous instrumentations, tumors or infections were excluded. Bone meal was collected from each screw placement and analyzed separately; preoperative antibiotics were analyzed in parallel. We stratified patients in native and preoperated patients who underwent a previous spinal decompression.
Results: We included 180 patients and analyzed bone dust from a total of 995 pilotholes for pedicle screws. The presence of bacteria was detected in 61.2% of the cases, in only 5.7% we detected abundant bacteria, in 20.8% we detected single bacteria and in 52.2% the bacteria were identified only in enrichment medium. C. acnes was the most often encountered bacteria (28.4%) in healthy bone meal specimens, followed by Staphylococcus epidermidis (25.3%) and Staphylococcus hominis (11.7%). We saw no difference between patients with a native or preoperated spine, nor between percutaneous and open instrumention.
Conclusion: Overall, bacterial presence was detected in more than half of the healthy bone specimens. Our preliminary data suggest a ubiquitous colonization, and screw loosening remains a complex and probably multifactorial pathology. Clinical symptoms and imaging should be correlated with positive microbiological results to correctly detect and not overestimate its pathogenicity.