DISC (Degenerate-disc infection study with contaminant control): pilot study of Australian cohort of patients without the contaminant control

Study Design. Prospective cohort study. Objective. To evaluate if degenerative disc-related back or neck pain and/or radicular symptoms are caused by infection with low virulent bacterial organisms. Summary of Background Data. The potential relationship between disc infection and disc degeneration-related symptoms remains controversial, with contradictory evidence available in the literature. Several studies have demonstrated the presence of infected extruded nucleus tissue from first-time disc herniation, implicating the role of disc microbial infection in disc degeneration. The current study is a pilot study evaluating if high infection rates are prevalent in the Australian degenerate disc cohort. Methods. Institutional ethics approval was obtained (HREC 13/218). The pilot project was a single spine center prospective cohort of patients undergoing spine surgery for degenerate disc disease. In each case, disc material was obtained and prolonged aerobic and anaerobic cultures performed as per methods used by Stirling et al. Results. To date, a total of 168 patients have been enrolled, with male: female=1:1. Surgical caseload includes 17.9% anterior cervical fusion, 35.0% anterior lumbar fusion, 40.7% lumbar discectomy, and 5.7% posterior lumbar fusions; 34.1% patients presented with neck pain, 31.6% with arm pain, 59.3% with leg pain, and 64.2% with back pain, and 20.2% of the patients received transforaminal or epidural or facet joint injections prior to surgery. In this pilot study, 19.6% were culture positive, with P. acnes predominant in 50%. Disc-only cultures were positive in 27.8% of lumbar cases and 18.5% of cervical cases, with predominant organisms being P. acnes. Conclusion. Similar to the infection rates from previous studies, this Australian cohort had 19.6% infection rates when disc-only cultures are performed. P. acnes is the predominant organism followed by Streptococcus sp. It is imperative to perform contaminant controls as such high infection with skin bugs is a significant finding.