Analyzing Bacterial Biofilm Formation on Cranioplasty Implants.

BACKGROUND

Cranioplasty (CP) is associated with high surgical site infections, compared to other deep-buried implant surgeries, including total knee and hip replacements.

PURPOSE: This study purpose was to measure and compare in vitro biofilm formation between polyether ether ketone (PEEK) and titanium CP implants.

STUDY DESIGN, AND

SETTING

To address the research purpose, the investigator designed and implemented an in vitro cross-sectional study. Samples matching custom-made CP implants design were produced at National Health Service North Bristol trust. Microbiology testing was carried out at University of Gloucestershire, School of Education Health and Science and Gloucestershire Hospitals National Health Service Foundation Trust.

PREDICTOR VARIABLES: The predictor variable was between the implant materials unfinished titanium (cp-Ti), pressed titanium (polished cp-Ti), titanium (Ti-6Al-4V), and PEEK.

MAIN OUTCOME VARIABLES: The primary outcome variable was the development of Staphylococcus aureus (S aureus) biofilm on prepared CP samples. Colony-forming unit test were undertaken and images were taken 24 hours post incubation, and Image J was used to count the colonies. Crystal violet biofilm assays were undertaken and absorbance levels of each well (570 um wavelength) and is proportional to the concentration of the crystal violet staining of S aureus biofilm formed on the sample surfaces.

COVARIATES: Not applicable.

ANALYSES: One-way analysis of variance statistical analysis and Tukey's post-hoc test were used to compare parameters between various groups. The level of statistical significance was set at P value .05.

RESULTS

The studies used n = 40 (100%) samples, cp-Ti n = 10 (25%), polished cp-Ti n = 10 (25%), Ti-6Al-4V n = 10 (25%), and PEEK n = 10 (25%). Microbiology tests were used to measure the biofilm formation of S aureus on manufactured samples. PEEK had a statistically significant higher biofilm formation when compared to polished cp-Ti (P < .04) and cp-Ti (P < .05). However, there was not statistically significant result between PEEK and Ti-6Al-4V (P < .12).

CONCLUSION AND RELEVANCE: This study found that commercially pure titanium and Ti-6Al-4V has more resistance to biofilm formation by S aureus than PEEK on CP implant surfaces. Titanium CP implants may help lower S aureus adhesion compared to other materials, possibly limiting the risk of infections related to S aureus and improving patients' safety.