Clinical Research Directory

Epigenetic and Molecular Biomarkers in Chronic Low Back Pain and Modic Changes

Sponsor: Oslo University Hospital

Summary

In the present study the investigators aim to examine the presence of bacteria in the disc and Modic Changes (MCs) (bone). A prospective study with 1-year follow-up of two patient populations undergoing elective spinal surgery (spinal fusion or disc herniation surgery) will be conducted. Patients previously operated on at index level will also be included, and evaluated as sub-groups. The following tissues are collected: dermis, sub-fascial tissue, nucleus pulposus, annulus fibrosus, and endplates. Endplate and anular biopsies are only performed in patients undergoing fusion surgery. In addition, air samples from the operating theatre during surgery are collected as negative controls. All tissue samples undergoing culturing should be processed within 4 hours of sampling. The time for sampling and culture processing is noted for each sample. Details are available in a published Method article. For each tissue sample, bacterial growth is recorded and identified at species level. Initially, the microbiologist grades the plates as "no growth", "possible contamination", and "significant growth". Possible contamination means that the bacteria may be derived from the environment and can be introduced at any step from the sample is taken to the analyses in the laboratory. The investigators will perform direct 16S rDNA nanopore sequencing on all frozen tissue samples and air samples. Other broad metagenomic methods may be considered, e.g., Illumina sequencing. Since Cutibacterium acnes is considered the main pathogen in this setting, the investigators will also use a specific quantitative PCR on all samples. In addition, the investigators will use whole genome sequencing on C. acnes isolates for phylogenetic analyses to compare isolates found in different samples from the same patient. Based on cultivation alone, samples will be graded as "significant growth", "possible contamination" or "no growth". Before unblinding, in preparation for the sensitivity analyses, "possible contamination" will be classified into a final categorization of "possible significant growth" or "no growth" based on PCR". In cases of a culture-negative nanopore-positive biopsy, the sample is classified as no growth when we find the same bacterial species in the air control sample as in the biopsy. Since the study was designed and the method article was prepared, nanopore sequencing technology has become available and incorporated into the present analysis. Although not part of the original protocol, nanopore sequencing was applied to the samples to complement the diagnostic approach. The results derived from nanopore sequencing will be included as part of prespecified sensitivity analyses to evaluate the robustness of the main finding. These analyses allow assessment of whether the inclusion of sequencing-based detection influences the overall estimates and conclusions, while maintaining the original study design. The microbiologists, the pathologist, statistician and clinicians are blinded until end of study. Blood-samples are collected to characterize gene expression patterns and related markers.

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