What triggers an episode of acute low back pain? A protocol of a replication case-crossover study.

OBJECTIVE: To describe all the procedures of a study that will replicate a previous case-crossover study investigating physical and psychosocial transient exposure risk factors for triggering an episode of acute non-specific low back pain (LBP) at emergency departments in an emerging country. METHODS: This case-crossover study will recruit 350 patients, aged between 18 and 80 years, with a new episode of acute non-specific LBP seeking care at emergency departments from public hospitals in Brazil. We will collect information about exposure to a range of physical (eg, awkward postures, lifting children or animals, vigorous physical activity) and psychosocial triggers (eg, distraction, tiredness, alcohol consumption) that were examined in the previous study. The exposure to each trigger during the 2 hours preceding the onset of LBP (case window) will be compared with exposure in the 2-hour periods ending 24 (24-26 hours) and 48 (48-50 hours) hours before the onset of back pain (control window). Conditional logistic regression models will be built to estimate ORs expressing the magnitude of increased risk of developing LBP associated with each factor. DISCUSSION: This study will enable the confirmation of previous findings regarding transient exposure to factors that increase risk for an episode of acute LBP in a different setting (at emergency departments of an emerging country). To minimise the potential for recall bias, the maximum time between episode onset and interview will be 7 days; we will encourage participants to use their smartphones and diaries to remember the investigated period. Also, our interview script asked participants to nominate the key aspects of each day. Despite these efforts, the retrospective study design means it is not possible to completely exclude potential for recall bias. Furthermore, participants will be blinded to the case and control periods. ETHICS AND DISSEMINATION: Ethics were granted by the Research Ethics Committee (#20310219.8.0000.0064). Study findings will be disseminated through publications and conference presentations.

Comparative efficacy and safety of surgical and invasive treatments for adults with degenerative lumbar spinal stenosis: protocol for a network meta-analysis and systematic review.

INTRODUCTION: Surgical and invasive procedures are widely used in adults with degenerative lumbar spinal stenosis when conservative treatments fail. However, little is known about the comparative efficacy and safety of these interventions. To address this, we will perform a network meta-analysis (NMA) and systematic review to compare the efficacy and safety of surgical and invasive procedures for adults with degenerative lumbar spinal stenosis. METHODS AND ANALYSIS: We will include randomised controlled trials assessing surgical and invasive treatments for adults with degenerative lumbar spinal stenosis. We will search AMED, CINAHL, EMBASE, the Cochrane Library and MEDLINE. Only English studies will be included and no restriction will be set for publication status. For efficacy, our primary outcome will be physical function. Secondary outcomes will include pain intensity, health-related quality of life, global impression of recovery, work absenteeism and mobility. For safety, our primary outcome will be all-cause mortality. Secondary outcomes will include adverse events (number of events or number of people with an event) and treatment withdrawal due to adverse effect. Two reviewers will independently select studies, extract data and assess the risk of bias (Revised Cochrane risk-of-bias tool for randomized trials) of included studies. The quality of the evidence will be evaluated through the Grading of Recommendations Assessment, Development and Evaluation framework. Random-effects NMA will be performed to combine all the evidence under the frequentist framework and the ranking results will be presented through the surface under the cumulative ranking curve and mean rank. All analyses will be performed in Stata and R. ETHICS AND DISSEMINATION: No ethical approval is required. The research will be published in a peer-reviewed journal. PROSPERO REGISTRATION NUMBER: CRD42018094180.