PSYCHOLOGICAL FACTORS AS PREDICTORS FOR SUCCESSFULL SPINAL CORD STIMULATION OUTCOME

Abstract

Spinal Cord Stimulation (SCS) has been used for decades to reduce chronic pain. It was always the medical doctor who decided whether a patient qualifies for the procedure (British Pain Society, 2009). Recent research has demonstrated that psychological factors such as anxiety, depression, poor coping strategies, and cognitive impairments all have an influence on successful SCS-outcomes (Blackburn et al., 2016; Stephenson, 2016). Several organizations tried to include the roll of psychologists and psychological factors in their guideline, but there is still no consensus. One thing the organizations have in common is that they claim that psychological assessment cannot be used as a predictor of a successful SCS-outcome. Due to lack of clarity the Diakonessenhuis questioned the way it was using their psychological assessment. The aim of the present study is to examine whether the psychological assessment, used by the Diakonessenhuis, yields valid information based on which it is possible to make a good prediction on successful SCS-outcome. To do this, a mediation analysis was conducted in which four psychometric tests – the Pain Coping Inventory, the Illness Cognition Questionnaire, the Hospital Anxiety and Depression Scale, and the Pain Catastrophizing Scale – were the independent factors, SCS-outcome the dependent factor, and recommendation the mediator. Data relating to 69 patients were collected from the electronic patient dossier of the Diakonessenhuis. The results demonstrate that psychological assessment does not provide a predictive value for successful SCSoutcome, and hence recommendation does not serve as a mediator. The psychological assessment should therefore not be used to predict successful SCS-outcome. However, it could still potentially be used to monitor psychological factors that might influence a successful outcome. The study had several limitations, including a small sample size and limited variability in the recommendations which might have influenced the power of the study. Further research is recommended.