Object: Lumbar discectomy is the most common surgical procedure performed in the US for patients experiencing back and leg pain from herniated lumbar discs. However, not all patients will benefit from lumbar discectomy. Patients with certain psychological predispositions may be especially vulnerable to poor clinical outcomes. The goal of this study was therefore to determine the role that preoperative depression and somatic anxiety have on long-term back and leg pain, disability, and quality of life (QOL) for patients undergoing single-level lumbar discectomy.
Methods: In 67 adults undergoing discectomy for a single-level herniated lumbar disc, the authors determined quantitative measurements of leg and back pain (visual analog scale [VAS]), quality of life (36-Item Short Form Health Survey [SF-36]), and disease-specific disability (Oswestry Disability Index) preoperatively and at 6 weeks, 3, 6, and 12 months after surgery. The degree of preoperative depression and somatization was assessed using the Zung Self-Rating Depression Scale and a modified somatic perception questionnaire (MSPQ). Multivariate regression analyses were performed to assess associations between Zung Scale and MSPQ scores with achievement of a minimum clinical important difference (MCID) in each outcome measure by 12 months postoperatively.
Results: All patients completed 12 months of follow-up. Overall, a significant improvement in VAS leg pain, VAS back pain, Oswestry Disability Index, and SF-36 Physical Component Summary scores was observed by 6 weeks after surgery. Improvements in all outcomes were maintained throughout the 12-month follow-up period. Increasing preoperative depression (measured using the Zung Scale) was associated with a decreased likelihood of achieving an MCID in disability (p = 0.006) and QOL (p = 0.04) but was not associated with VAS leg pain (p = 0.96) or back pain (p = 0.85) by 12 months. Increasing preoperative somatic anxiety (measured using the MSPQ) was associated with decreased likelihood of achieving an MCID in disability (p = 0.002) and QOL (p = 0.03) but was not associated with leg pain (p = 0.64) or back pain (p = 0.77) by 12 months.
Conclusions: The Zung Scale and MSPQ are valuable tools for stratifying risk in patients who may not experience clinically relevant improvement in disability and QOL after discectomy. Efforts to address these confounding and underlying contributors of depression and heightened somatic anxiety may improve overall outcomes after lumbar discectomy.