Protocol for the development of a core outcome set for cauda equina syndrome: systematic literature review, qualitative interviews, Delphi survey and consensus meeting

Introduction Cauda equina syndrome (CES) is a serious neurological condition most commonly due to compression of the lumbosacral nerve roots, which can result in significant disability. The evidence for acute intervention in CES is mainly from retrospective studies. There is heterogeneity in the outcomes chosen for analysis in these studies, which makes it difficult to synthesise the data across studies. This study will develop a core outcome set for use in future studies of CES, engaging with key stakeholders and using transparent methodology. This will help ensure that relevant outcomes are used in future and will facilitate attempts to summarise data across studies in systematic reviews. Methods and analysis A systematic literature review will document all the outcomes for CES after surgery mentioned in the literature. The qualitative interviews with patients with CES will be semistructured, audio recorded, transcribed and thematically analysed with the use of NVivo V.10 to identify outcomes and determine the themes described. The outcomes from the literature review and patient interviews will be combined and prioritised to determine what the most important outcomes are in CES research studies to patients and healthcare professionals. The prioritisation will be done through a two-round iterative Delphi survey and a consensus meeting. This process will decide the core outcome set for patients with CES. Ethics and dissemination REC and HRA approval was obtained on the 6/12/16 for the qualitative interviews from South Central-Hampshire A REC. REC reference 16/SC/0587. REC and HRA approval was obtained on 26/3/18 for the Delphi process and consensus meeting from North West-Greater Manchester Central REC. REC reference was 18/NW/0022. The final core outcome set will be published and freely available.