A recent study found that patients who presented with presurgical depressive symptoms reported more severe symptoms preoperatively and postoperatively. However, despite residual symptoms, these patients may benefit more from surgery than those without depressive symptoms. The results were presented by Christopher K Kepler (Thomas Jefferson University Hospital, Philadelphia, USA) at the 46th annual meeting of the Cervical Spine Research Society (CSRS; 6–8 December 2018, Scottsdale, USA).
The investigators, Kepler and colleagues at Thomas Jefferson University Hospital, describe the relationship between the mental component score (MCS) of the Short Form 12 Survey and disability after an anterior cervical discectomy and fusion (ACDF) as “uncertain”. The purpose of the study, therefore, was to investigate whether presurgical depressive symptoms measured by the MCS influenced the clinical benefit of ACDF.
Mean improvement in neck disability index was 16.8 points (95% confidence interval [CI]: -19.93, -13.72, p<0.001). Compared to the patients with an MCS >45.6, patients with an MCS <45.6 had higher neck disability index both preoperatively, 48.86 (95% CI: 25.04, 33.07) vs. 22.01 (95% CI: 18.44, 25.58; p=0.01), but both groups demonstrated a “significant improvement” from baseline (p<0.0001). While the patients with an MCS <45.6 had more disability postoperatively, these patients demonstrated even greater benefit from surgery, as the improvement of the neck disability index was actually greater than patients with a higher MCS, -19.8 vs. -13.7. Kepler and colleagues included 264 patients in the study with a mean follow up of 19.8 (range 12–46.6) months. The cohort included 135 patients with an SF-12 MCS of <45.6 and 129 with an SF-12 MCS >45.6. The mean age was 53.1 (range 18–84) years old, and the mean BMI was 29.6 (range 18.7–54.9).
Furthermore, mean improvement of PCS after ACDF was 7.78 (95% CI: 6.27, 7.3; p<0.001) and no significant difference in baseline PCS was found between patients with an MCS (32.87 [95% CI: 31.69, 34.06]) and those with an MCS >45.6 (33.54 [95% CI: 31.92, 35.16]). Both groups demonstrated “statistically significant” improvement from baseline, with the final PCS scores of 39.06 (95% CI: 37.13, 40.99) in patients with an MCS <45.6 PCS (p=0.043). “Importantly,” the investigators found that while the final PCS score was lower in patients with an MCS <45.6, they reported more improvement compared to patients with an MCS >45.6.
The analysis comparing patients with and without depressive symptoms on the MCS who underwent an ACDF for a degenerative cause, evaluated outcomes including neck disability index, SF-12 PCS, visual analogue scale (VAS) arm pain, and VAS neck pain. The authors note that patients with trauma, tumour infection, previous cervical spine surgery, or those with less than one year of clinical follow up were excluded. The investigators used an MCS <45.6 as a diagnostic criterion of depressive symptoms.
Kepler and colleagues note that a number of studies have evaluated the impact of depression on outcomes after ACDF with mixed results. While one of these studies found no difference in patients with depressive symptoms, multiple others found worse outcomes, including, most recently, a 2017 study by Phan published in the Journal of Spine Surgery.
Commenting on the significance of the results, Kepler proposes: “Patients with depressive symptoms may have lower preoperative and postoperative function and worse disability, but have similar improvement after ACDF and should be given full consideration as surgical candidates.” However, he also notes that “The study is limited by its retrospective nature and questions about the suitability of MCS as a proxy for depressive symptoms”.
“There continues to be uncertainty about the impact of depression on outcome after spinal surgery,” Kepler adds. “Prospective research with patients who have been clinically diagnosed with depression and depression-spectrum disorders would allow a more accurate evaluation of the role of depressive symptoms on clinical outcome.”