P.147 Exploring the bacterial hypothesis of low back pain: a prospective cohort study

Background: Occult bacterial infection is a proposed etiology of low back pain (LBP). However, a causative link between LBP and bacteria remains unconfirmed. Herein, we determined the incidence of occult discitis in patients receiving surgery for LDH. Methods: Study Design: prospective cohort study. Inclusion criteria: consecutive adult patients undergoing discectomy for symptomatic LDH. Exclusion criteria: prior epidural steroid use, prior spinal surgery, and antibiotic use within 2 weeks of surgery. Tissue samples: Four nuclear tissue and ligamentum flavum (control) samples were obtained per patient using stringent aseptic protocol. Samples underwent 16S-PCR and culturing. Results: Eighty-one patients were enrolled (mean age 43.3±13.3 years). All (100%) of tissue samples were negative by 16S PCR and no virulent species were detected. Nuclear and ligament cultures were both negative in 51 (62.9%) cases. Cultures were positive for nuclear tissue only, ligament only, or both in 14.8%, 12.3%, and 9.9% of cases, respectively. Fifteen of 20 (75%) disc positive samples grew a single colony of an indolent species. Conclusions: The findings of this prospective cohort study of consecutive patients receiving surgery for LDH do not support the theory of occult discitis. All samples were 16S-PCR negative, and most cultures were negative or grew a single colony suggestive of contamination.