Cutaneous immunopathology of long-standing complex regional pain syndrome.

BACKGROUND: Both increased mast cells numbers and raised immune mediator concentrations indicate immune activation in the affected skin of patients with early complex regional pain syndrome (CRPS), but little is known about regional immune cell involvement in late-stage CRPS. The aim of the current study was to determine skin immune cell populations in long-standing CRPS. METHODS: Using 6-mm skin punch biopsies from CRPS-affected and non-affected tissues, and a combination of chemical and immunofluorescence staining, we examined the density and function of key cell populations including mast cells, epidermal Langerhans cells (LCs) and tissue resident T-cells. RESULTS: We found no significant differences in either overall immune cell infiltrates, or mast cell density between CRPS-affected and non-affected sub-epidermal tissue sections, contrasting recent findings in early CRPS by other groups. However, CD1a(+) LC densities in the epidermal layer were significantly decreased in affected compared to non-affected CRPS limbs (p < 0.01). T-cell clones isolated from CRPS-affected sub-epidermal tissues displayed a trend towards increased IL-13 production in ELISPOT assays when compared to T-cells isolated from non-affected areas, suggesting a Th2 bias. CONCLUSIONS: Immune cell abnormalities are maintained in late-stage CRPS disease as manifest by changes in epidermal LC density and tissue resident T-cell phenotype.

Phantom limb pain, cortical reorganization and the therapeutic effect of mental imagery.

Using functional MRI (fMRI) we investigated 13 upper limb amputees with phantom limb pain (PLP) during hand and lip movement, before and after intensive 6-week training in mental imagery. Prior to training, activation elicited during lip purse showed evidence of cortical reorganization of motor (M1) and somatosensory (S1) cortices, expanding from lip area to hand area, which correlated with pain scores. In addition, during imagined movement of the phantom hand, and executed movement of the intact hand, group maps demonstrated activation not only in bilateral M1 and S1 hand area, but also lip area, showing a two-way process of reorganization. In healthy participants, activation during lip purse and imagined and executed movement of the non-dominant hand was confined to the respective cortical representation areas only. Following training, patients reported a significant reduction in intensity and unpleasantness of constant pain and exacerbations, with a corresponding elimination of cortical reorganization. Post hoc analyses showed that intensity of constant pain, but not exacerbations, correlated with reduction in cortical reorganization. The results of this study add to our current understanding of the pathophysiology of PLP, underlining the reversibility of neuroplastic changes in this patient population while offering a novel, simple method of pain relief.

The systematic assessment of short-term functional recovery after major joint arthroplasty.

Despite extensive information about long-term recovery from major joint arthroplasty, little attention has been given to the measurement of functional recovery in the immediate postoperative period. Therefore assumptions about the importance of physical therapy during this period remain untested. We devised a way of recording functional recovery before discharge, based primarily on the achievement of objective milestones. This was incorporated into routine physiotherapy practice and applied to sequential patients undergoing elective hip (n = 163) or knee (n = 66) replacement. Six months later, we followed up 160 patients, of whom 145 completed questionnaires to assess subjective physical and emotional state and functional recovery. The method was sensitive to known influences on pace of recovery, including type of arthroplasty (hip vs knee) and surgeons' differing requirements for mobilization. In addition, we were able to confirm and quantify sources of variation in functional recovery which previously were suspected but unconfirmed: in particular, the timing of early mobilization. Outcome at 6 months was unrelated to objective functional recovery in hospital, although fatigue and wellbeing at this time were predicted by physiotherapists' subjective assessment of patients' motivation before discharge. The findings can be used to inform patients and as a source of comparison data for the assessment of functional recovery in other centres. More importantly, the procedure reported may be applied to quantify functional recovery in routine practice and thereby expose variability in recovery to scientific scrutiny.