Changes in pain, pain identity, and self-rated health among adults with chronic pain before and after treatment with spinal cord stimulation

Purpose: To assess changes in pain levels, self-rated health (SRH)and identity of a pain patient in adults with chronic pain from referral to implantation of a spinal cord stimulation (SCS) device to about 6 weeks following implantation. Methods: Patients with chronic pain (N=148) were recruited following their referral to SCS (mean age 54 ± 15, 43% women, 62% not working, 50% need mobility assistance or aids). Participants filled in questionnaires at referral (T1) and again 8 months after referral(T2). The questionnaire included average pain over the past twoweeks rated on a 1-100 visual analogue scale, a 5-point self-rating of general health, and a 9-item acceptance of disability scale adapted topain, which indicates pain intrusion and identification with being apain patient. Results: Thirty patients (20%) did not undergo the SCS procedure (noSCS, nSCS), 43 (29%) underwent only temporary implantation of a SCSdevice and discontinued this treatment ("disappointed", dSCS), and 75(51%) continued to implantation of a permanent SCS device (pSCS; forthis group, T2 was about 6 weeks post-implantation). At baseline, these groups did not differ in any of the demographic or study measures, withthe exception of lower pain levels in the nSCS at baseline, compared tothe other two groups (mean 71 ± 21, 82 ± 13, and 79 ±17, for then SCS, dSCS, and pSCS groups, respectively; F(2,143)=3.34, p=.04). One-hundred nineteen patients (80%) filled in T2 questionnaires (21, 33,and 65, in the nSCS, dSCS, and pSCS). Repeated measures ANOVA revealed significant differences in the extent of change in pain over time(F(2,96)=7.00, p=.01): Pain levels remained the same in the nSCS but significantly decreased in the other two groups, much more so inthe pSCS. SRH improved only for the pSCS (controlling for T1 pain;F(2,108)=4.32, p=.02). Change in pain identity was of borderlinesignificance (controlling for T1 pain; F(2,93)=2.41, p=0.09): Stronger identity was reported by the dSCS with no change in the other groups. Conclusions: Continuous use of SCS relieves pain and leads to improved SRH yet pain still dominates these patients' lives and thoughts. It is important to note that only about half underwent permanent SCS. Those who failed temporary SCS, reported greater pain identity and intrusion, despite some improvement in pain levelsover time.