Bacterial adhesion characteristics on implant materials for intervertebral cages: titanium or PEEK for spinal infections?

Theresa Krätzig,Klaus Christian Mende,Sven Oliver Eicker,Martin Stangenberg,Simon von Kroge,Malte Mohme,Samira Weisselberg,Marc Dreimann,Manfred Westphal

doi:10.1007/s00586-020-06705-z

Theresa Krätzig, Klaus Christian Mende + Show 7 more

Open Access

https://doi.org/10.1007/s00586-020-06705-z

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Abstract

PurposeSurgical intervention with intercorporal stabilisation in spinal infections is increasingly needed. Our aim was to compare titanium and polyetheretherketon (PEEK) cages according to their adhesion characteristics of different bacteria species in vitro.MethodsPlates made from PEEK, polished titanium (Ti), two-surface-titanium (TiMe) (n = 2–3) and original PEEK and porous trabecular structured titanium (TiLi) interbody cages (n = 4) were inoculated in different bacterial solutions, S.aureus (MSSA, MRSA), S.epidermidis and E.coli. Growth characteristics were analysed. Biofilms and bacteria were visualised using confocal- and electron microscopy.ResultsQuantitative adherence of MSSA, MRSA, S.epidermidis and E.coli to Ti, TiMe and PEEK plates were different, with polished titanium being mainly advantageous over PEEK and TiMe with significantly less counts of colony forming units (CFU) for MRSA after 56 h compared to TiMe and at 72 h compared to PEEK (p = 0.04 and p = 0.005). For MSSA, more adherent bacteria were detected on PEEK than on TiMe at 32 h (p = 0.02). For PEEK and TiLi cages, significant differences were found after 8 and 72 h for S.epidermidis (p = 0.02 and p = 0.008) and after 72 h for MSSA (p = 0.002) with higher bacterial counts on PEEK, whereas E.coli showed more CFU on TiLi than PEEK (p = 0.05). Electron microscopy demonstrated enhanced adhesion in transition areas.ConclusionFor S.epidermidis, MSSA and MRSA PEEK cages showed a higher adherence in terms of CFU count, whereas for E.coli PEEK seemed to be advantageous. Electron microscopic visualisation shows that bacteria did not adhere at the titanium mesh structure, but at the border zones of polished material to rougher parts.

Highlights

Infections of the spinal column such as spontaneous osteomyelitis or post-surgical infections are rare but increasing pathologies due to the ageing population and increasing numbers of comorbidities with mortality rates up to 17% [1,2,3]
The only significant difference in those two materials was at 32 h for methicillin-resistant S.aureus (MSSA) with significantly less bacterial adherence on TiMe plates compared to PEEK plates (p = 0.02)
Our study evaluates and compares PEEK and 3D printed trabecular metal cages according to their bacterial adhesion characteristics aiming to gain recommendations for the use in cases of osteomyelitis or spondylodiscitis where there is still no final guideline what kind of material for intercorporal cages is best to prevent re-infections and guarantee bony fusion [17]

Summary

Introduction

Infections of the spinal column such as spontaneous osteomyelitis or post-surgical infections are rare but increasing pathologies due to the ageing population and increasing numbers of comorbidities with mortality rates up to 17% [1,2,3]. Mild infections can be treated conservatively whereas patients with sepsis, osseous destruction and/or neurological deficits due to compression of the spinal cord or the nerve roots need decompressive surgery and/or stabilisation. The most common causative bacterial species for spondylodiscitis or osteomyelitis are S.aureus with an incidence between 30 and 80%, S.epidermidis with rates up to over 10% and MRSA (6.1%). Gram-negative bacteria are responsible for up to 25% of spinal infections, with E.coli being reported as the most common (5.6%) [9,10,11]

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