Bacterial growth in patients with low back pain and Modic changes: protocol of a multicentre, case-control biopsy study.

INTRODUCTION: Bacterial infection and Modic changes (MCs) as causes of low back pain (LBP) are debated. Results diverged between two randomised controlled trials examining the effect of amoxicillin with and without clavulanic acid versus placebo on patients with chronic LBP (cLBP) and MCs. Previous biopsy studies have been criticised with regard to methods, few patients and controls, and insufficient measures to minimise perioperative contamination. In this study, we minimise contamination risk, include a control group and optimise statistical power. The main aim is to compare bacterial growth between patients with and without MCs. METHODS AND ANALYSIS: This multicentre, case-control study examines disc and vertebral body biopsies of patients with cLBP. Cases have MCs at the level of tissue sampling, controls do not. Previously operated patients are included as a subgroup. Tissue is sampled before antibiotic prophylaxis with separate instruments. We will apply microbiological methods and histology on biopsies, and predefine criteria for significant bacterial growth, possible contamination and no growth. Microbiologists, surgeons and pathologist are blinded to allocation of case or control. Primary analysis assesses significant growth in MC1 versus controls and MC2 versus controls separately. Bacterial disc growth in previously operated patients, patients with large MCs and growth from the vertebral body in the fusion group are all considered exploratory analyses. ETHICS AND DISSEMINATION: The Regional Committees for Medical and Health Research Ethics in Norway (REC South East, reference number 2015/697) has approved the study. Study participation requires written informed consent. The study is registered at ClinicalTrials.gov (NCT03406624). Results will be disseminated in peer-reviewed journals, scientific conferences and patient fora. TRIAL REGISTRATION NUMBER: NCT03406624.

Long-term comparison of anterior (ALIF) versus transforaminal (TLIF) lumbar interbody fusion: a propensity score-matched register-based study.

PURPOSE: Anterior (ALIF) and transforaminal (TLIF) lumbar interbody fusion have shown similar clinical outcomes at short- and medium-term follow-ups. Possible advantages of ALIF in the long run could be better disc height and lumbar lordosis and reduced risk of adjacent segment disease. We aimed to study if ALIF could be associated with superior clinical outcomes than TLIF at long-term follow-up. METHODS: We analysed 535 patients treated with ALIF or TLIF of the L5-S1 spinal segment between 2007 and 2017 who completed long-term follow-up in a national spine registry database (NORspine). We defined treatment success after surgery as at least 30% improvement in Oswestry Disability Index (ODI) at long-term follow-up. Patients treated with ALIF and TLIF and who responded at long term were balanced by propensity score matching. The proportions of successfully treated patients within each group were compared by numbers and percentages with corresponding relative risk. RESULTS: The mean (95%CI) age of the total study population was 50 (49-51) years, and 264 (49%) were females. The mean (95%CI) preoperative ODI score was 40 (39-42), and 174 (33%) had previous spine surgery. Propensity score matching left 120 patients in each treatment group. At a median (95%CI) of 92 (88-97) months after surgery, we found no difference in proportions successfully treated patients with ALIF versus TLIF (68 (58%) versus 77 (65%), RR (95%CI) = 0.88 (0.72 to1.08); p = 0.237). CONCLUSIONS: This propensity score-matched national spine register study of patients treated with ALIF versus TLIF of the lumbosacral junction found no differences in proportions of successfully treated patients at long-term follow-up. LEVEL OF EVIDENCE I: Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Incidental dural tears associated with worse clinical outcomes in patients operated for lumbar spinal stenosis.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: Incidental dural (ID) tear is a common complication of spine surgery with a prevalence of 4-10%. The association between ID and clinical outcome is uncertain. Former studies found only minor differences in Oswestry Disability Index (ODI). We aimed to examine the association of ID with treatment failure after surgery for lumbar spinal stenosis (LSS). METHODS: Between 2007 and 2017, 11,873 LSS patients reported to the national Norwegian spine registry (NORspine), and 8,919 (75.1%) completed the 12-month follow-up. We used multivariate logistic regression to study the association between ID and failure after surgery, defined as no effect or any degrees of worsening; we also compared mean ODI between those who suffered a perioperative ID and those who did not. RESULTS: The mean (95% CI) age was 66.6 (66.4-66.9) years, and 52% were females. The mean (95% CI) preoperative ODI score (95% CI) was 39.8 (39.4-40.1); all patients were operated on with decompression, and 1125 (12.6%) had an additional fusion procedure. The prevalence of ID was 4.9% (439/8919), and the prevalence of failure was 20.6% (1829/8919). Unadjusted odds ratio (OR) (95% CI) for failure for ID was 1.51 (1.22-1.88); p < 0.001, adjusted OR (95% CI) was 1.44 (1.11-1.86); p = 0.002. Mean postoperative ODI 12 months after surgery was 27.9 for ID vs. 23.6 for no ID. CONCLUSION: We demonstrated a significant association between ID and increased odds for patient-reported failure 12 months after surgery. However, the magnitude of the detrimental effect of ID on the clinical outcome was small.