Prognostic factors for outcome following lumbar spine fusion surgery: a systematic review and narrative synthesis.

PURPOSE: The objective of this study was to identify and evaluate the value of prognostic factors related to disability, pain and quality of life (QoL) for adult patients undergoing lumbar spine fusion surgery (LSFS).

METHODS

Two reviewers independently searched the literature, assessed eligibility, extracted data and assessed risk of bias and certainty of evidence. Key electronic databases were searched [PubMed, CINAHL, EMBASE, MEDLINE, PEDro and ZETOC] using pre-defined terms [e.g. LSFS] to 20/9/2020; with additional searching of journals, reference lists and unpublished literature. Prospective cohort studies with ≥ 12-month follow-up after LSFS were included. Narrative synthesis was based on recommendations by Cochrane Consumers and Communication Review Group. The GRADE tool enabled assessment of certainty of evidence. Prognostic factors and outcome were analysed and summarised when examined in ≥ 2 studies and when results pointed in the same direction in ≥ 75% of studies.

RESULTS

Sixteen studies (n =  8388, 2 low and 14 high risk of bias) were included with 39 prognostic factors identified. There is low certainty evidence that higher pre-operative severity of leg pain predicts greater improvement of leg pain and that pre-operative working predicts less post-operative disability both at 1-2-year follow-up. Other found associations were of very low certainty evidence.

CONCLUSION

No moderate to high certainty evidence exists. Use of leg pain and pre-operative working may be valuable predictors of outcome to inform clinical decision-making and advice regarding LSFS surgery. There is need for adequately powered low-risk-of-bias prospective observational studies to further investigate candidate prognostic factors.