Development and validation of two clinical prediction models to inform clinical decision making for lumbar spinal fusion surgery for degenerative disorders, and rehabilitation following surgery: protocol for a prospective observational study

Research output: Contribution to journalArticlepeer-review


  • Martin L. Verra
  • Andrew Emms
  • Michael Reddington
  • Ashley Cole
  • Paul Willems
  • Lorin Benneker
  • David Selvey
  • Mike Hutton
  • Martijn Heymans
  • J. Bart Staal

External organisations

  • Department of Physiotherapy, Bern University Hospital
  • Department of Physiotherapy, The Royal Orthopaedic Hospital NHS Foundation Trust
  • Department of Physiotherapy, Sheffield Teaching Hospitals NHS Trust, Royal Hallamshire Hospital
  • Department of Orthopaedics and Trauma, Sheffield Teaching Hospitals NHS Foundation Trust
  • Maastricht University Medical Centre
  • Department of Orthopaedic Surgery Inselspital, University of Berne
  • Amplitude Clinical
  • Princess Elizabeth Orthopaedic Centre (PEOC), Royal Devon & Exeter NHS Foundation Trust
  • Department of Epidemiology and Biostatistics, VU University Medical Center


Introduction: Potential predictors of poor outcome will be measured at baseline: (1) preoperatively to develop a clinical prediction model to predict which patients are likely to have favourable outcome following lumbar spinal fusion surgery (LSFS) and (2) postoperatively to predict which patients are likely to have favourable long-term outcomes (to inform rehabilitation).

Methods and analysis: Prospective observational study with a defined episode inception of the point of surgery. Electronic data will be collected through the British Spine Registry and will include patient-reported outcome measures (eg, Fear-Avoidance Beliefs Questionnaire) and data items (eg, smoking status). Consecutive patients (≥18 years) undergoing LSFS for back and/or leg pain of degenerative cause will be recruited. Exclusion criteria: LSFS for spinal fracture, inflammatory disease, malignancy, infection, deformity and revision surgery. 1000 participants will be recruited (n=600 prediction model development, n=400 internal validation derived model; planning 10 events per candidate prognostic factor). The outcome being predicted is an individual’s absolute risk of poor outcome (disability and pain) at 6 weeks (objective 1) and 12 months postsurgery (objective 2). Disability and pain will be measured using the Oswestry Disability Index (ODI), and severity of pain in the previous week with a Numerical Rating Scale (NRS 0–10), respectively. Good outcome is defined as a change of 1.7 on the NRS for pain, and a change of 14.3 on the ODI. Both linear and logistic (to dichotomise outcome into low and high risk) multivariable regression models will be fitted and mean differences or ORs for each candidate predictive factor reported. Internal validation of the derived model will use a further set of British Spine Registry data. External validation will be geographical using two spinal registries in The Netherlands and Switzerland.

Ethics and dissemination: Ethical approval (University of Birmingham ERN_17-0446A). Dissemination through peer-reviewed journals and conferences.


Original languageEnglish
Article numbere021078
JournalBMJ open
Issue number5
Publication statusPublished - 22 May 2018