Complex regional pain syndrome: advancing rehabilitation through better evaluation and treatment
Introduction: Complex regional pain syndrome (CRPS) is a form of neuropathic
pain that sometimes develops after trauma or surgery. While diagnostic criteria
have been debated, there is agreement participation in rehabilitation should be
the primary management. However, there are gaps in the evidence guiding
assessment and treatment choices for individuals with CRPS. The purpose of
this thesis was to advance the rehabilitation of CRPS by 1) ongoing development
and refinement of evaluations for the specific symptoms of CRPS, and 2) to
investigate effectiveness of a new treatment (somatosensory rehabilitation)
posited to address allodynia associated with CRPS.
Methods: We conducted a series of 4 studies addressing various aspects of
CRPS assessment and the somatosensory rehabilitation method: a) a cognitive
debriefing study for content validation of the Patient-Reported Hamilton Inventory
for CRPS; b) English translation and cultural validation of the Radboud
Evaluation of Sensitivity; c) a retrospective cohort study of the effectiveness of
somatosensory rehabilitation for allodynia in the upper limb; and d) a pilot study
of the somatosensory rehabilitation method to consider the measurement
properties of the embedded evaluation tools of allodynography and the rainbow
pain scale, and to provide estimates for future controlled trials of effectiveness.
Results: The cognitive debriefing study identified potentially problematic items,
and constructs which needed enhancement in future versions of the PR-HICRPS
assessment. The second paper reported the translation and cultural
validation of the RES-E, finding support for test-retest reliability, internal
consistency, and preliminary evidence for construct validity and reproducibility.
The third paper presented preliminary evidence of a strong effect size for the
SRM in an uncontrolled consecutive cohort. Finally, the fourth paper provides an
interm analysis of the psychometric properties of allodynography and the rainbow
pain scale, and estimates large sample sizes will be required for future trials.
Discussion and Conclusion: None of the assessment tools described herein is ready for unrestricted use in clinical practice or research. Although the effect size estimates for somatosensory rehabilitation from the retrospective cohort are encouraging, the incomplete pilot data suggests large, multi-site trials and careful selection of the primary outcome measures will be required for future, rigorous trials of this method.