The spine literature makes it clear that medical and psychosocial comorbidities result in worse patient reported outcomes following spine surgery. However, most papers have looked at absolute scores on patient reported outcome measures (PROMs) rather than change scores or recovery ratios. Even fewer have analyzed the treatment effect of surgery—the difference in change scores between patients treated with surgery and non-operative care. Most of this literature has evaluated lumbar surgery patients, and far fewer papers have looked at the relationship between psychosocial factors and outcomes in cervical spine surgery. In order to help fill this void, Dr. Divi and colleagues from Thomas Jefferson University stratified 264 ACDF patients into a depressed and non-depressed group based on SF-36 mental component scale (MCS) scores at baseline. They used two thresholds for depression (MCS < 45.6 and MCS < 35) based on prior literature, and the results were effectively the same for the two depression thresholds. Not surprisingly, they found that the depressed group had worse baseline Neck Disability Index (NDI), VAS Neck, and VAS Arm pain scores and worse post-operative scores at an average follow-up of 19 months. However, the depressed group improved significantly more on NDI and VAS neck and arm pain scores than the non-depressed group. The recovery ratios were similar for the two groups. Multivariate analyses controlling for some baseline differences demonstrated that depression was not an independent predictor of change score for any PROM.
This paper supports prior literature demonstrating that depressed patients have worse baseline and post-operative PROMs compared to non-depressed patients. There is less literature looking at change scores following cervical spine surgery than lumbar surgery, though most literature on lumbar surgery has shown less improvement in the depressed cohort. In the SPORT lumbar disk herniation study, patients with self-reported depression and MCS < 35 had worse baseline and post-operative ODI scores as well as less improvement on the ODI than non-depressed patients and those with MCS > 35.1 However, there was no difference in the treatment effect of surgery as depressed patients also improved less with non-operative treatment compared to non-depressed patients. The current paper did not include a non-operative group, so the treatment effect of surgery could not be determined. Additionally, MCS scores reflect mental health in general and are not specific for depression, so it is possible that the results would have been different if a depression-specific questionnaire had been used to define the groups. The authors also combined radiculopathy and myelopathy patients, who have different post-operative outcomes. However, the depressed and non-depressed cohorts had a similar proportion of myelopathy patients, so this is unlikely to have affected outcomes. The authors did not control for baseline PROM scores, which were worse in the depressed group, so it is possible that the greater degree of improvement seen in the depressed group is due to less of a ceiling effect in the non-depressed group. The recovery ratio helps to take into account the baseline PROM score differences, and there were no differences in those analyses. This paper adds to the growing literature suggesting that while patients with medical and psychosocial comorbidities have worse absolute outcomes, they still benefit significantly from surgery. Many of these characteristics are not easily modifiable, so surgery should still be offered to patients with mental health diagnoses. Both patients and surgeons should be aware that their absolute outcomes may not be as good as patients without such comorbidities.
Please read Dr. Divi's article on this topic in the February 1 issue. Does this change how you consider depression in the surgical decision-making process? Let us know by leaving a comment on The Spine Blog.
Adam Pearson, MD, MS
Associate Web Editor
1. Pearson A, Lurie J, Tosteson T, et al. Who should have surgery for an intervertebral disc herniation? Comparative effectiveness evidence from the spine patient outcomes research trial. Spine 2012;37:140-9.