Surgical versus nonoperative treatment for lumbar disc herniation: four-year results for the Spine Patient Outcomes Research Trial (SPORT)

Abstract

Study design: Concurrent, prospective, randomized, and observational cohort study.

Objective: To assess the 4-year outcomes of surgery versus nonoperative care.

Summary of background data: Although randomized trials have demonstrated small short-term differences in favor of surgery, long-term outcomes comparing surgical to nonoperative treatment remain controversial.

Methods: Surgical candidates with imaging-confirmed lumbar intervertebral disc herniation meeting SPORT eligibility criteria enrolled into prospective, randomized (501 participants), and observational cohorts (743 participants) at 13 spine clinics in 11 US states. Interventions were standard open discectomy versus usual nonoperative care. Main outcome measures were changes from baseline in the SF-36 Bodily Pain (BP) and Physical Function (PF) scales and the modified Oswestry Disability Index (ODI - AAOS/Modems version) assessed at 6 weeks, 3 months, 6 months, and annually thereafter.

Results: Nonadherence to treatment assignment caused the intent-to-treat analyses to underestimate the treatment effects. In the 4-year combined as-treated analysis, those receiving surgery demonstrated significantly greater improvement in all the primary outcome measures (mean change surgery vs. nonoperative; treatment effect; 95% CI): BP (45.6 vs. 30.7; 15.0; 11.8 to 18.1), PF (44.6 vs. 29.7; 14.9;12.0 to 17.8) and ODI (-38.1 vs. -24.9; -13.2; -15.6 to -10.9). The percent working was similar between the surgery and nonoperative groups, 84.4% versus 78.4% respectively.

Conclusion: In a combined as-treated analysis at 4 years, patients who underwent surgery for a lumbar disc herniation achieved greater improvement than nonoperatively treated patients in all primary and secondary outcomes except work status.

Trial registration: ClinicalTrials.gov NCT00000410.

Conflict of interest statement

Conflicts Disclosure

Dr. Lurie reports receiving consulting fees from the Foundation for Informed Medical Decision Making; Dr. A. Tosteson reports receiving grant support from Zimmer, Inc; Dr. Hilibrand reports receiving consulting fees for product development and royalties for cervical spine implants and femoral ring allograft; Dr. Albert reports receiving reimbursement for attending a symposium, fees for speaking, organizing education, and consulting, and funds for research from DePuy Spine; he has also worked as an independent contractor for DePuy Spine, lecturing on spine topics related to surgery with or without instrumental and molecular biology of the disc. He has received royalties and/or holds patents for instrumentation that he has designed. He manages his conflicts through transparency and by avoiding when possible inclusion of products he’s specifically designed and by being generic in his discussions.

Figures

Figure 1. Exclusion, Enrollment, Randomization and Follow-up of Trial Participants

The values for surgery, withdrawal, and death are cumulative over 4 years. For example, a total of 1 patient in the group assigned to surgery died during the 4-year follow-up period. [Data set 04/10/2008]

Figure 2. Primary Outcomes (SF-36 Bodily Pain and Physical Function, and Oswestry Disability Index) in the Randomized and Observational Cohorts during 2 Years of Follow-up

The graphs show both the intent-to-treat and the as-treated analyses for the randomized cohort (column on the left) and the as-treated analysis for the observation cohort (column on the right). The horizontal dashed line in each of the 4 SF-36 graphics represents normal values adjusted for age and sex. The I bars represent 95% confidence intervals. At 0 months, the floating data points represent the observed mean scores for each study group, whereas the data points on plot lines represent the overall means used in the adjusted analyses.

Figure 3

Secondary Outcomes in the Randomized and Observational Cohorts during 2 Years of Follow-up