A. Soroka1, A. Lubetzky Vilnai2, O. Murphy3, J. Leitner4, S. Shabat4, E. Ashkenazi5, Y. Floman5, M. Moffat2, Y. Masharawi1
1Tel Aviv University, Spinal Research Laboratory, Department of Physical Therapy, The Stanley Steyer School of Health Professions, Sackler Faculty of Medicine, Tel Aviv, Israel, 2New York University, Department of Physical Therapy, Steinhardt School of Culture Education and Human Development,, New York, United States, 3McMaster University, Department of Mathematics and Statistics, New York, United States, 4Meir Medical Center, Spine Unit, Kfar Saba, Israel, 5Assuta Hospital, Israel Spine Center, Tel Aviv, Israel

Background: Worldwide, increasing numbers of older adults undergo lumbar spine surgery. This number is expected to increase in the upcoming years.   Variability in surgical outcomes and complications rate indicate that candidates for surgery should be assessed with high-quality diagnostic and predictive tests so that their surgical decision is informed by a realistic prediction of treatment outcome.

Purpose: The primary goal of this study was to determine if personal and functional factors can predict self-reported successful outcomes in patients suffering from chronic low back pain (CLBP) and leg symptoms following either a decompression or fusion lumbar surgery or a non-surgical ‘wait and see’ approach.  

Methods: This prospective, controlled, non-randomized study compared patients who underwent lumbar fusion or decompression surgery to those who were recommended to surgery but chose to continue with conservative management (‘wait and see’). Patients were recruited from Meir Medical Center and from Assuta Medical Center in Israel. Patients underwent a comprehensive clinical assessment including functional tests [single-leg-stance test, four-step-square-test, 8-foot-up-and-go test, 400 m walk test, 30 second sit-to-stand test, grip strength, heel raise test, passive straight leg raise (PSLR), and chair sit and reach test (CSRT) and questionnaires reporting pain, disability and other personal factors. Response to treatment was assessed long-term in 12 months and success predictors were identified using Oswestry Disability Index (ODI).
In order to determine which variables predicted success, we ran a multiple linear regression model. Variable selection was performed with multiple imputations for missing values. Backward selection was done with a p value 0.1 as an indication for removal of a variable.

Results: The prediction model for ODI change from baseline to 12 months showed the following: 
  • Surgery predicted on average 18.8 points greater improvement.
  • For every additional hour of sitting per day at baseline, a patient improved 1.66 points less  on the ODI on average.
  • Every additional meter traveled in 2 minutes. at baseline, predicted 0.11 points less improvement on average.
  • If a patient could reach beyond their toes on their worst side they tended to improve less. Every cm reached beyond toes predicted 0.47 points less change on ODI.
  • Every additional heel raise at baseline on the weaker side, predicted on average 1.27 points more improvement.
This model overall explained 30% of the variation in ODI change.

Conclusion(s): While surgery predicted greater improvement after 12 months, this study suggests that several tests commonly done by physical therapists should be administered when a patient is being evaluated for lumbar surgery. For example, we found that the simple CSRT was more relevant to a patient’s success than the commonly administered PSLR. Many patients who preferred to avoid the PSLR were able to perform the CSRT. It appears that patients who had better range of motion and walking ability at baseline had less room for improvement on a self-reported disability scale. On the other hand, having better strength at baseline predicted greater improvement.

Implications: While this model needs to be further investigated it does suggest that functional performance should be considered during decision-making regarding surgery.

Funding, acknowledgements: The work was not funded.

Keywords: lumbar spine surgery, prediction success, functional outcomes

Topic: Musculoskeletal: spine

Did this work require ethics approval? Yes
Institution: Assuta medical center, Meir Medical Center
Committee: IRB-Helsinki Committee
Ethics number: #MMC-0006-15 and #0020-16-ASMC

All authors, affiliations and abstracts have been published as submitted.

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