Introduction: There has been a generic dictum in spine and musculoskeletal clinical research that 2 year follow-up is necessary for patient reported outcomes (PRO) to adequately assess the treatment effect of surgery; however, the rationale for this duration is not evidence based. The purpose of this study is to determine the PRO follow-up time necessary to ensure that the effectiveness of a lumbar surgical intervention is adequately captured.
Methods: Using the different dimensions of PROs from the Canadian Spine Outcomes and Research Network (CSORN) prospective database the time-course to recovery plateau after lumbar spine surgery was assessed for lumbar disc herniation, degenerative spondylolisthesis, and spinal stenosis. One-way ANOVAs with post-hoc testing were used to compare the following standardized PROs at baseline, 3, 12, and 24 months post-operatively: Disability Scale (DS), Visual Analogue Scale (VAS) leg and back pain, and Short form (SF-12) mental and physical component summary (MCS/PCS) scores.
Results: There were significant differences determined by one-way ANOVAs for all spine pathologies and specific PROs (p<0.0001). Time to plateaued recovery after surgery for lumbar disc herniation (n=334) and lumbar spondylolisthesis (n=452) followed the same course for the following PROs: VAS back and leg pain, 3 months; DS, 12 months; PCS, 12 months; and MCS,3 months. After surgery for lumbar stenosis (n=435) recovery plateaued at 3 months on all PROs. Beyond these time points no further significant improvements in PRO were seen.
Conclusions: Specific health dimensions of PROs follow distinctly different recovery plateaus, indicating a two-year postoperative follow-up is not required for all PROs to accurately assess the treatment effect of lumbar spinal surgery. Ultimately the clinical research question should dictate follow-up time and the health dimension of the outcome measure utilized, however there is now evidence to guide the specific duration of follow-up for pain, function and mental quality of life dimensions.
Patient Care: This information will be useful in designing and maintaining prospective registries and for counselling patients and monitoring their recovery after lumbar spine surgery
Learning Objectives: -Two-year postoperative follow-up is not required for all PROs to accurately assess the treatment effect of lumbar spinal surgery
-Ultimately the clinical research question should dictate follow-up time and the health dimension of the outcome measure utilized, however there is now evidence to guide the specific duration of follow-up for pain, function and mental quality of life dimensions.