ObjectiveTo assess the efficacy of three months of antibiotic treatment compared with placebo in patients with chronic low back pain, previous disc herniation, and vertebral endplate changes (Modic changes).DesignDouble blind, parallel group, placebo controlled, multicentre trial.SettingHospital outpatient clinics at six hospitals in Norway.Participants180 patients with chronic low back pain, previous disc herniation, and type 1 (n=118) or type 2 (n=62) Modic changes enrolled from June 2015 to September 2017.InterventionsPatients were randomised to three months of oral treatment with either 750 mg amoxicillin or placebo three times daily. The allocation sequence was concealed by using a computer generated number on the prescription.Main outcome measuresThe primary outcome was the Roland-Morris Disability Questionnaire (RMDQ) score (range 0-24) at one year follow-up in the intention to treat population. The minimal clinically important between group difference in mean RMDQ score was predefined as 4.ResultsIn the primary analysis of the total cohort at one year, the difference in the mean RMDQ score between the amoxicillin group and the placebo group was −1.6 (95% confidence interval −3.1 to 0.0, P=0.04). In the secondary analysis, the difference in the mean RMDQ score between the groups was −2.3 (−4.2 to−0.4, P=0.02) for patients with type 1 Modic changes and −0.1 (−2.7 to 2.6, P=0.95) for patients with type 2 Modic changes. Fifty patients (56%) in the amoxicillin group experienced at least one drug related adverse event compared with 31 (34%) in the placebo group.ConclusionsIn this study on patients with chronic low back pain and Modic changes at the level of a previous disc herniation, three months of treatment with amoxicillin did not provide a clinically important benefit compared with placebo. Secondary analyses and sensitivity analyses supported this finding. Therefore, our results do not support the use of antibiotic treatment for chronic low back pain and Modic changes.Trial registrationClinicalTrials.gov NCT02323412.

Background Metal implants may introduce severe artifacts in computed tomography (CT) images. Over the last few years dedicated algorithms have been developed in order to reduce metal artifacts in CT images. Purpose To investigate and compare metal artifact reduction algorithms (MARs) from four different CT vendors when imaging three different orthopedic metal implants. Material and Methods Three clinical metal implants were attached to the leg of an anthropomorphic phantom: cobalt-chrome; stainless steel; and titanium. Four commercial MARs were investigated: SmartMAR (GE); O-MAR (Philips); iMAR (Siemens); and SEMAR (Toshiba). The images were evaluated subjectively by three observers and analyzed objectively by calculating the fraction of pixels with CT number above 500 HU in a region of interest around the metal. The average CT number and image noise were also measured. Results Both subjective evaluation and objective analysis showed that MARs reduced metal artifacts and improved the image quality for CT images containing metal implants of steel and cobalt-chrome. When using MARs on titanium, all MARs introduced new visible artifacts. Conclusion The effect of MARs varied between CT vendors and different metal implants used in orthopedic surgery. Both in subjective evaluation and objective analysis the effect of applying MARs was most obvious on steel and cobalt-chrome implants when using SEMAR from Toshiba followed by SmartMAR from GE. However, MARs may also introduce new image artifacts especially when used on titanium implants. Therefore, it is important to reconstruct all CT images containing metal with and without MARs.

Background: Limited reliability data exist for evaluation of spinal edema changes on magnetic resonance imaging (MRI) with short tau inversion recovery (STIR) sequences. Purpose: To assess the inter-observer reliability for evaluation of STIR signal increase related to Modic changes (MCs) on MRI of the lumbar spine. Material and Methods: We prospectively included 120 patients imaged to confirm their eligibility for the AIM (Antibiotics In Modic changes) trial. Three experienced radiologists independently evaluated MCs on T1-/T2-weighted fast spin-echo images and subsequently MC-related STIR signal increases. Inter-observer reliability was analyzed at four endplates (L4-S1) by calculating kappa values and means of differences with 95% limits of agreement. Results: Overall agreement (mean Fleiss' kappa for all endplates and observers) was very good for presence of STIR signal increase (0.86), and moderate for its categorized height (0.51), anteroposterior extent (0.48), and volume (0.56). For height of region with STIR signal increase measured in % points of vertebral body height, the largest mean of differences was 6.9 and widest range for limits of agreement was AE22.3 for all endplates combined. The corresponding numbers were 11.2 AE 34.5 for anteroposterior extent of the STIR signal increase measured in % points of anteroposterior endplate diameter and 0.9 AE 7.6 for its maximum measured intensity on a % point scale (0% ¼ normal vertebral marrow intensity, 100% ¼ cerebrospinal fluid intensity). Conclusion: Inter-observer reliability was very good for the presence and intensity of MC-related STIR signal increases, and moderate for their size.

High-signal changes of the alar and transverse ligaments are common in WAD1-2 and unlikely to represent age-dependent degeneration. Their male and left-side preponderance cannot be explained by variation in ligament stretching or image artefacts. Further studies are needed to clarify whether such changes are caused by trauma.