Association between sciatica and Propionibacterium acnes

We hypothesised that the inflammation seen around the nerve root in patient s with sciatica may be caused by microbial infection, We used a newly devel oped serological test to diagnose deep-seated infections caused by low viru lent gram-positive microorganisms. 43 of 140 (31%) patients with sciatica t ested positive. Intervertebral disc material from a further 36 patients wit h severe sciatica who had undergone microdiscectomy was cultured for the pr esence of microorganisms. 19 of these patients (53%) had positive cultures after long-term incubation. Propionibacterium acnes was isolated from 16 of the 19 (84%) positive samples, Low virulent microorganisms, in particular P acnes, might be causing a chronic low-grade infection in the lower Interv ertebral discs of patients with severe sciatica, These microorganisms could have gained access to the spinal disc after previous minor trauma.