Background. Epidural steroid injections can provide temporary relief of symptoms in the treatment of lumbar spinal stenosis. Surgery is indicated when conservative measures fail. We hypothesise that patients who gain temporary relief of symptoms from the administration of epidural steroid injections are more likely to result in an improvement in symptoms following surgical intervention compared to patients who do not respond to injection therapy. Method. The records of patients who had received both an epidural injection and surgical intervention for lumbar spinal stenosis between July 2008 and July 2010 were identified and retrospectively reviewed. Relief of symptoms following epidural injection was noted at 6 weeks post procedure and the patients symptoms following surgical intervention was noted and classified according to MacNab's criteria at 3 months post-surgery. Results. 60 patients who received both an epidural injection and surgical intervention for lumbar spinal stenosis were identified. 76% of patients who gained relief of symptoms from epidural injection scored good or excellent according to MacNab's criteria following surgery (n=34). Only 30% of patients who did not respond to injection therapy scored good or excellent according to MacNab's criteria following surgical intervention (n=5). Conclusion. Patients who gained temporary relief of symptoms from epidural injection were more likely to benefit from surgical intervention in the treatment for lumbar spinal stenosis. No conflicts of interest. No funding obtained. We confirm that this abstract has not been previously published in whole or substantial part nor has it been presented previously at a national meeting

Background. Recently, some studies have focused attention on the possibility that anaerobic pathogens of low virulence could constitute an etiological factor in disc herniation. There have been isolated such strains, predominantly Propionibacterium acne, between 7 and 53% of patients undergoing surgery for disc pathology. According to these studies, patients with anaerobic infections of the disc are more likely to develop Modic changes in the adjacent vertebrae. The aim of this work was to test this hypothesis by growing in specific media the disc material extracted in a series of lumbar discectomy and relating this factor with the presence of pre-intervention Modic changes. Methods. A total of 22 consecutive patients undergoing primary unisegmental discectomy for lumbar disc herniation (77.2% male, mean age 40.1 ± 9.1 years) were included. All patients were immunocompetent and none had previously received an epidural steroid injection prior surgery. MRI study confirmed the disc herniation. Following strict antiseptic protocols, the extracted disc material was sent for slow-growth anaerobic enriched culture (>10 days). Results. In total, anaerobic cultures were positive in 7 cases (31.8%) all men. In 5 of these cases, the symptoms developed with an acute onset. The isolated germs were always unique: Propionibacterium acne (3), Streptococcus parasanguinis (1), Actinomyces naeslundii (1), Actinomyces meyeri (1) and methicillin sensitive Staphylococcus epidermidis. Only two (28.6%) of these 7 patients had Modic changes on MRI prior surgery (one type I, one type 2). None of the patients with negative cultures had Modic changes. Conclusions. These findings support the theory that anaerobic infections of low virulence and slow growth may contribute to the pathogenesis of herniated discs. However, these cases do not necessarily develop type 1 Modic changes as previously speculated. Level of evidence. Level IV