Purpose To investigate the prevalence of infected herniated nucleus material in lumbar disc herniations and to determine if patients with an anaerobic infected disc are more likely to develop Modic change (MC) (bone oedema) in the adjacent vertebrae after the disc herniation. MCs (bone oedema) in vertebrae are observed in 6 % of the general population and in 35-40 % of people with low back pain. These changes are strongly associated with low back pain. There are probably a mechanical cause and an infective cause that causes MC. Several studies on nuclear tissue from herniated discs have demonstrated the presence of low virulent anaerobic microorganisms, predominantly Propionibacterium acnes, in 7-53 % of patients. At the time of a herniation these low virulent anaerobic bacteria may enter the disc and give rise to an insidious infection. Local inflammation in the adjacent bone may be a secondary effect due to cytokine and propionic acid production. Methods Patients undergoing primary surgery at a single spinal level for lumbar disc herniation with an MRI-confirmed lumbar disc herniation, where the annular fibres were penetrated by visible nuclear tissue, had the nucleus material removed. Stringent antiseptic sterile protocols were followed. Results Sixty-one patients were included, mean age 46.4 years (SD 9.7), 27 % female. All patients were immunocompetent. No patient had received a previous epidural steroid injection or undergone previous back surgery. In total, microbiological cultures were positive in 28 (46 %) patients. Anaerobic cultures were positive in 26 (43 %) patients, and of these 4 (7 %) had dual microbial infections, containing both one aerobic and one anaerobic culture. No tissue specimens had more than two types of bacteria identified. Two (3 %) cultures only had aerobic bacteria isolated. In the discs with a nucleus with anaerobic bacteria, 80 % developed new MC in the vertebrae adjacent to the previous disc herniation. In contrast, none of those with aerobic bacteria and only 44 % of patients with negative cultures developed new MC. The association between an anaerobic culture and new MCs is highly statistically significant (P = 0.0038), with an odds ratio of 5.60 (95 % CI 1.51-21.95). Conclusion These findings support the theory that the occurrence of MCs Type 1 in the vertebrae adjacent to a previously herniated disc may be due to oedema surrounding an infected disc. The discs infected with anaerobic bacteria were more likely (P \ 0.0038) to develop MCs in the adjacent vertebrae than those in which no bacteria were found or those in which aerobic bacteria were found.

Study Design:Retrospective cohort study.Objectives:It is estimated that 10 000 patients seek medical care due to cervical radiculopathy every year in Denmark. Although the natural course is usually favorable, around 20% undergo surgery for cervical degenerative disease every year in Denmark. We aim to evaluate the patient-reported results and satisfaction of anterior cervical decompression and fusion over a 5-year period from a single Danish center for spine surgery.Methods:This study is a retrospective study based on prospectively collected data from 318 consecutive patients treated with anterior cervical decompression and fusion over 1 to 3 levels. Data in the DaneSpine registry was collected pre- and postoperatively, and at 1 year after surgery. The outcome measures were Neck Disability Index (NDI), European Quality of Life 5D (EQ-5D), visual analogue score (VAS), and Short Form-36 Physical Component Summary (SF-36 PCS).Results:Of 318 cases enrolled, 272 (85.5%) had follow-up data available at a minimum 1-year postoperatively. The mean preoperative NDI was 40.0 and improved to 22.7. Mean EQ-5D was 0.50 and improved to 0.70, and mean VAS arm was 60.4 improved to 26.4. All improvements were statistically significant. A total of 74.3% were back to work 1 year after surgery. Achieving minimal clinically important difference (MCID) in VAS neck and SF-36 PCS was strongly correlated to patient satisfaction.Conclusion:Patients who undergo anterior cervical discectomy and fusion can expect improvement in their pain and disability, with 74.3% of patients reporting a positive change in health status after surgery.