Which Variables Are Associated With Patient-reported Outcomes After Discectomy? Review of SPORT Disc Herniation Studies.

BACKGROUND: The Spine Patient Outcomes Research Trial (SPORT) evaluated the effects of surgery versus nonoperative treatment for lumbar intervertebral disc herniation (IDH), among other pathologies. Multiple subgroup analyses have been completed since the initial publications, which have further defined which patient factors lead to better or worse patient-reported outcomes; however, the degree to which these factors influence patient-reported outcomes has not been explored. QUESTIONS/PURPOSES: We reviewed the subgroup analyses of the SPORT IDH studies to answer the following questions: (1) What factors predicted improvement in patient-reported outcomes after operative or nonoperative treatment of lumbar IDH? (2) What factors predicted worse patient-reported outcomes compared to baseline after operative or nonoperative treatment of lumbar IDH? And (3) what factors influenced patient-reported outcomes of surgery in patients with lumbar IDH?
METHODS: We conducted a MEDLINE(®) search to identify the subgroup analyses of the SPORT IDH data that were responsive to our study questions. Eleven articles were identified that met our search criteria.
RESULTS: The patient factors associated with larger improvements in Oswestry Disability Index at 4 years with either surgical or nonoperative treatment included a higher baseline Oswestry Disability Index, BMI of less than 30, not being depressed, being insured, having no litigation pending, not having workers compensation, and having symptoms for less than 6 weeks, though there were others. Factors leading to improvement with surgical treatment were mostly related to anatomic characteristics of the disc herniation such as posterolateral and sequestered herniations. There were no patient or clinical factors identified that were associated with worse patient-reported outcomes compared to baseline after either operative or nonoperative treatment. At 2-year followup, the treatment effects were greater for those patients with upper-level herniations, patients not receiving workers compensation, and nondiabetic patients. In a 4-year multivariate analysis, being married, without joint problems, and having worse symptoms at baseline resulted in greater treatment effect with surgery.
CONCLUSIONS: While most patients with IDH will likely see improvement with either surgical or nonoperative treatment, there are patient-related factors that can help predict which subgroups will demonstrate a greater improvement with surgery, such as not having joint problems, being married, having worsening symptoms at baseline, and not having diabetes. These results can help providers and patients when discussing treatment options. LEVEL OF EVIDENCE: Level I, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.