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

UNLABELLED: 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.

Repetitive intrathecal VEGF(165) treatment has limited therapeutic effects after spinal cord injury in the rat.

Neuropathic pain and motor deficits are detrimental consequences of injury to the spinal cord. In experimental settings, numerous neuroprotective agents are being explored for their therapeutic benefits. Vascular endothelial growth factor (VEGF) is an interesting candidate molecule in this respect since it is not only associated with angiogenesis, but also with neuroprotection and neurite growth. Other investigators have reported improved motor outcomes following intraparenchymal VEGF treatment. Here we demonstrate the therapeutic effects of daily intrathecal treatment of the contused thoracic rat spinal cord with the 165-isoform of VEGF during the first week after injury. We show that VEGF treatment resulted in a statistically significant attenuation of mechanical, but not thermal, hypersensitivity of the hindpaws, while motor deficits remained unaffected. Tissue sparing was also unchanged by VEGF treatment. Microglial responses at the lumbar spinal cord, which have been linked with spinal cord injury-induced hypersensitivity, were found to be unaffected by VEGF treatment. We conclude that repetitive intrathecal VEGF delivery has limited therapeutic effects on spinal cord injury outcome.

Treatment of patients with complex regional pain syndrome type I with mannitol: a prospective, randomized, placebo-controlled, double-blinded study.

UNLABELLED: To assess the effects of intravenous administration of the free radical scavenger mannitol 10% on complaints associated with complex regional pain syndrome Type I (CRPS I), a randomized, placebo-controlled, double-blinded trial was performed. Forty-one CRPS I patients according to the Bruehl et al diagnostic criteria, were included in 2 outpatient pain clinics of 2 university medical centers and randomly assigned to receive either 10% mannitol iv in 1 L 0.9% NaCL in 4 hours for 5 consecutive days or equal volumes of 0.9% NaCL (placebo). Patients in both groups received physical therapy according to protocol and rescue pain medication if required. Complaints on impairment and disability level and quality of life were assessed up to 9 weeks after baseline, with primary measurement points at 2, 6, and 9 weeks. Monitoring of pain using the visual analogue scale took place continuously during the course of the trial. Except for a significant improvement on a subscale of the Jebsen-Taylor hand function test, no significant differences were found between mannitol and placebo treatment. Changes in both groups in the course of the trial were small and clinically irrelevant on all measurement indices. We conclude that intravenous administration of 10% mannitol is not more effective than placebo in reducing complaints for CRPS I patients and provides no addition to already-established interventions for CRPS I. Whether 10% mannitol can provide beneficial effects for subgroups of CRPS I patients with a pathophysiological profile more closely fitting the presumed mode of action for this intervention remains to be established. PERSPECTIVE: This article addresses the efficacy of the intravenous administration of the free radical scavenger mannitol for treatment of CRPS type 1. This intervention is not more effective than placebo in reducing complaints for CRPS I patients and provides no addition to already-established interventions for CRPS I.