A multivariate prognostic model for pain and activity limitation in people undergoing lumbar discectomy

Abstract

Purpose: The purpose of this study was to identify a multivariate predictive model for 6-month outcomes on overall pain, leg pain and activity limitation in patients undergoing lumbar discectomy. Identification of predictors of outcome for lumbar discectomy has the potential to assist identifying treatment targets, clinical decision making and disease understanding.

Materials and methods: Prospective cohort design. Ninety-seven patients deemed by study surgeons to be suitable for lumbar discectomy completed a comprehensive clinical and radiological baseline assessment. At 6-months post surgery outcome measures of overall and leg pain (visual analogue scale) as well as activity limitation (Oswestry Disability Index) were completed. Univariate and multivariate analyses were conducted to determine the best multivariate predictive model of outcome.

Results: In the multivariate model, presence of a compensation claim, longer duration of injury and presence of below knee pain and/or parasthesia were negative prognostic indicators for at least two of the outcomes. Peripheralization in response to mechanical loading strategies was a positive prognostic indicator for overall pain and leg pain. A range of other prognostic indicators for one outcome were also identified. The prognostic model explained up to 32% of the variance in outcome.

Conclusions: An 11-factor prognostic model was identified from a range of clinically and radiologically assessed variables in accordance with a biopsychosocial model. The multivariate model has potential implications for researchers and practitioners in the field. Further high quality research is required to externally validate the prognostic model, evaluate effect of the identified prognostic factors on treatment effectiveness and explore potential mechanisms of effect.

Keywords:

• Lumbar radiculopathy
• prognosis
• discectomy
• prospective
• cohort

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Surgeons from the Epworth, Melbourne Health and Freemasons Hospitals in Victoria, Australia provided administrative support to the study at no cost. Dr. Omar Kaddour received a Melbourne Research Scholarship from The University of Melbourne for his Doctor of Philosophy candidature for which this study was a significant component.