Award Title: Predictors of Outcome in Sciatica patients following an Epidural steroid injection: the POiSE study.
Funder: Health Education England

Abstract: Research Question In adults with disc-related sciatica, what patient, clinical and imaging characteristics are associated with pain and function outcomes following epidural steroid injection (ESI)? Background Sciatica is a shooting leg pain, with or without symptoms of numbness or muscle weakness. In most cases (90%) sciatica is due to a lumbar disc herniation compressing the lumbar spinal nerve root(s), with associated inflammation. Up to 30% of sciatica patients do not improve and are referred to specialist spinal services for tests and further treatments, such as injections and/or surgery. The NICE guideline recommends ESIs for treating severe disc-related sciatica pain. In England the annual cost of ESIs for sciatica is approximately 30 million. Currently, there is no clear evidence on which patients are more likely to do well with ESI. The overall aim of this proposal is to offer patients with disc-related sciatica better individualised information about their likelihood of improvement in leg pain following ESI. The overall objective is to develop and validate a prognostic model to support patient and clinical decision-making regarding this intervention. Specific Objectives and Methods Work-package 1 Objective:Identify key candidate factors potentially associated with outcome following ESI. Methods: Systematic review and meta-analysis of factors predictive of outcome following ESI. Multidisciplinary expert clinical consensus workshop followed by electronic survey with two Delphi rounds to agree the factors potentially associated with outcome following ESI. Work-package 2 Objectives: (i) describe prognosis in patients with severe sciatica, (ii) determine prognostic factors that predict patients' outcomes following ESI, (iii) develop and internally validate a prognostic model for outcome following ESI, (iv) consider differences in outcomes and prognostic factors in those who do, and do not, have ESI treatment. Methods/Analysis: Multi-centre, observational, prospective cohort study nested in routine clinical care recruiting patients with disc-related sciatica, considered suitable for an ESI as part of their normal care. Prognosis for the cohort will be described. For the prognostic model, 439 patients who receive an ESI will be recruited. The primary outcome is leg pain intensity (0-10) at 6 weeks following ESI collected via weekly text messages from the day of consent until 12 weeks following ESI, and at 6 months. Secondary outcome measures will be collected via questionnaires at baseline, 3 and 6 months. Prognostic factors will be tested in those who do not have an ESI (a 'control' group). Statistical analyses will include multivariable linear and logistic regression with mixed effects model, prognostic modelling, classification and regression tree analysis and longitudinal latent class analysis. Work-package 3 Objectives: Externally validate the prognostic model and explore its usefulness with patients and clinicians. Methods: External validation of the prognostic model in separate trial and routine clinical practice data. Workshop with clinicians and patients to inform post-fellowship work to develop a clinically useful tool to support decision-making when considering ESI. Anticipated impact and dissemination This research will directly inform decision-making by patients and clinicians, who will have better information on their likelihood of benefit following ESI. Results will inform UK guidelines and dissemination strategies for sciatica management.

Lay Abstract: Sciatica can be very painful and in most cases is due to a disc herniation ('bulging' or 'slipped' disc) pressing on a spinal nerve. Sciatica symptoms include severe leg pain, usually below the knee, often accompanied by pins and needles, numbness or muscle weakness in the leg. Pain improves for most people with time, but for some, the pain persists and they are referred to specialist NHS spinal services for an opinion on further management. One management option, if the magnetic resonance imaging (MRI) scan confirms a disc herniation, is a spinal epidural steroid injection (ESI) of anti-inflammatory medicine. The aim of an ESI is to relieve leg pain, improve function and reduce the need for spinal surgery. We know from previous studies that ESIs, on average, provide some relief of leg symptoms in the short-term. For some patients they work well, but not for others. Currently we do not know which patients benefit and which do not. This is the gap in knowledge that this study will address. The aims of the study are to identify and test factors, including patient characteristics, clinical examination and imaging findings that help us to predict who does well and who doesn't after an ESI and explore how this information can be used in clinical practice. Design and methods There are three work-packages in the study. In work-package one (WP1), I will compile a list of factors that could be associated with outcome following ESI. First I will summarise evidence from previous research about the potential factors (e.g. age, pain severity, MRI findings). Then I will ask expert clinicians, who manage patients with severe sciatica (e.g. orthopaedic surgeons, specialist physiotherapists), to agree on a list of factors. At the end of WP1, there will be agreement on which factors to include in the clinical study in work-package two. Work-package two (WP2) is a large clinical study which will recruit 439 patients suffering from sciatica resulting from a herniated disc in the lower back, considered by the clinician as suitable for an ESI to manage their leg pain. I will include patients who have an ESI as well as patients who are suitable and referred for an ESI but do not go on to have this treatment (for example their symptoms recover while waiting for the ESI). Patients who agree to participate will receive a weekly text message for 12 weeks and again at 6 months, asking to rate their leg pain severity in the last week. Participants will also complete postal questionnaires at baseline, 3 and 6 months. Using this information, I can determine what combination of factors predict who does well and who doesn't after an ESI and compare them in the group who did not have an ESI. In work-package three (WP3) I will test if the combination of factors identified in WP2, predict which patients do well with an ESI but in a new group of sciatica patients, using data from clinical trials and routinely collected data of patients who had an ESI.I will explore with patients and clinicians how to use the findings from WP2 in the clinical setting to help clinicians and sciatica patients make better decisions about ESI treatment.Patient and Public involvement Patients with sciatica have shaped this application and will be involved throughout this study advising on issues including recruitment, wording of text messages, questionnaire design and how the findings can be used in clinical practice. Conclusion This research will mean clinicians can offer sciatica patients better information about their likelihood of improvement following ESI, and support patient and clinical decision-making about this treatment.

Research Activity Codes: 6.1 PHARMACEUTICALS
Health Categories: NEUROLOGICAL;MUSCULOSKELETAL