Psychiatria Fennica (Nov 2019)
HIGH LEVEL OF ANXIETY PREDICTS A POOR RESPONSE TO SPINAL CORD STIMULATION IN FAILED BACK SURGERY SYNDROME: A PROSPECTIVE STUDY
Abstract
Spinal cord stimulation (SCS) is an established and cost-effective treatment for neuropathic pain resulting from failed back surgery syndrome (FBSS). Psychological distress is a risk factor both in the development of FBSS and for reduced efficacy in SCS. The impact of psychological factors on SCS outcome is still poorly understood, and more research is warranted to gain a better understanding of the matter. The objective of this prospective study was to investigate the prevalence of anxiety symptoms pre-surgically and at 6 and 12 months post-surgically, and to examine their association with depressive symptoms, pain intensity and pain-related disability in patients with FBSS treated with SCS. Beck Anxiety Inventory (BAI) was used to assess anxiety symptoms, Beck Depressive Inventory (BDI) to assess depressive symptoms, Numeric Pain Rating Scale (NRS) to assess pain intensity, painDETECT to assess neuropathic pain and Oswestry Disability Index (ODI) to assess pain-related disability at baseline and at 6- and 12-month follow-ups. A total of 118 consecutive consenting patients referred to SCS at Kuopio University Hospital (KUH) between January 1, 2015 and December 31, 2018 were assessed at baseline, of whom the follow-up data at 6 and 12 months was available for 59 patients. Among those who received a BAI score of <16 at baseline, signifying minimal to mild anxiety, statistically significant improvements were observed for the NRS (p<0.001), ODI (p=0.001) and painDETECT (p<0.001) at follow-up, whereas among those who reported a BAI score of ≥16, signifying moderate to severe anxiety, statistically significant improvement was observed in painDETECT (p=0.003), but not in NRS (p=0.267) nor ODI (p=0.110). No statistically significant improvement was observed in depressive or anxiety symptoms at follow-up. Conclusions Among patients reporting moderate to severe anxiety at baseline, the SCS outcome was significantly worse at 1-year follow-up, than among those reporting only minimal to mild anxiety.
