Pain-related fear, perceived harmfulness of activities, and functional limitations in complex regional pain syndrome type I

Numerous studies have shown that pain-related fear is one of the strongest predictors of pain disability in patients with chronic musculoskeletal pain, and there is evidence that the reduction of pain-related fear through an exposure treatment can be associated with restoration of functional abilities in patients with complex regional pain syndrome type I (CRPS-I). These findings suggest that pain-related fear may be associated with functional limitations in neuropathic pain as well. The aim of the current study was to test whether the debilitating role of pain-related fear generalizes to patients with CRPS-I. The results of 2 studies are presented. Study I includes a sample of patients with early CRPS-I referred to an outpatient pain clinic. In Study II, patients with chronic CRPS who are members of a patients' association were invited to participate. The results show that in early CRPS-I, pain severity but not fear of movement/(re)injury as measured with the Tampa Scale for Kinesiophobia was related to functional limitations. In patients with chronic CRPS-I, however, perceived harmfulness of activities as measured with the pictorial assessment method significantly predicted functional limitations beyond and above the contribution of pain severity. Not fear of movement/(re)injury in general, but the perceived harmfulness of activities appears a key factor that might be addressed more systematically in the clinical assessment of patients with CRPS-I. These results support the idea that pain-related fear might be a promising concept in the understanding of pain disability in patients with neuropathic pain.

Perspective: This is the first study showing that perceived harmfulness of activities contribute to the functional limitations in CRPS-I. The current findings may help clinicians customizing cognitive-behavioral treatments for patients with chronic neuropathic pain.