Background: Psychological factors are recognised as influencing the outcome of spinal cord
stimulation (SCS) although there is currently no consensus as to which factors impact upon SCS
efficacy.
Objective: To identify psychological characteristics that may impact the efficacy of SCS.
Study Design: Prospective evaluation.
Setting: Single secondary care center in Dudley, United Kingdom.
Methods: Patients: Seventy-five patients were initially recruited and 56 patients (31 women
and 25 men) were followed-up for 12-months. Intervention: SCS for the management of chronic
non-cancer pain. Main Outcome Measures: Outcome measures assessed at baseline, 6 months,
and 12 months following SCS implantation included the visual analogue scale (VAS), Oswestry
disability index (ODI), hospital anxiety and depression (HAD) scale, and the pain coping strategies
questionnaire (PCSQ).
Results: Statistically significant improvements were observed for the VAS (P < 0.001), ODI (P =
0.011), anxiety (P = 0.042), and depression (P = 0.010) in the HAD scale and for the subscales
reinterpreting pain sensation (P = 0.018), control over pain (P = 0.001), and ability to decrease pain
(P < 0.001) of the PCSQ. We observed that depression and autonomous coping (control over pain,
ability to reduce pain, and catastrophizing) may impact sensory aspects such as pain intensity and
disability scores affecting the outcome of SCS treatment. Age at time of implant and duration of
pain prior to implant were also found to impact SCS efficacy.
Limitations: It has been reported that loss of analgesia may be experienced within 12 to 24
months following SCS implantation and therefore, it would be of interest to follow patients over
a longer period.
Conclusions: This study demonstrates that psychological aspects such as depression and
autonomous coping may impact SCS treatment. Addressing these issues prior to SCS implantation
may improve SCS long-term outcome.
Key words: Spinal cord stimulation, chronic pain, psychological characteristics, depression,
autonomous coping