Pain
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Randomized Controlled Trial
Experimental pelvic pain facilitates pain provocation tests and causes regional hyperalgesia.
The extra-articular sacroiliac joint (SIJ) structure is a potential source for low back and pelvic pain. This study hypothesised that experimental pain induced in a superficial pelvic ligament causes (1) hyperalgesia to pressure, (2) distinct pain referral, and (3) an increased frequency of positive pain provocation tests of the SIJ complex. Thirty healthy subjects (15 females) participated in this study designed as a randomised crossover trial. ⋯ PPTs at the injection site and lateral to S2 were significantly reduced after hypertonic saline compared with baseline and isotonic saline (P<0.002). Significantly more subjects had positive pain provocation tests after hypertonic (67% of subjects) compared with isotonic saline (20%; P<0.001). These data demonstrate that the extra-articular SIJ structure accommodates nociceptors that are capable of inducing pain referral and regional hyperalgesia sensitive to manual pain provocation tests similar to what previously have been found in pelvic girdle pain patients.
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Comparative Study
Impaired spatial body representation in complex regional pain syndrome type 1 (CRPS I).
Recently, a shift of the visual subjective body midline (vSM), a correlate of the egocentric reference frame, towards the affected side was reported in patients with complex regional pain syndrome (CRPS). However, the specificity of this finding is as yet unclear. This study compares 24 CRPS patients to 21 patients with upper limb pain of other origin (pain control) and to 24 healthy subjects using a comprehensive test battery, including assessment of the vSM in light and dark, line bisection, hand laterality recognition, neglect-like severity symptoms, and motor impairment (disability of the arm, shoulder, and hand). ⋯ 1-way analysis of variance, t-tests, significance level: 0.05. In the dark, CRPS patients displayed a significantly larger leftward spatial bias when estimating their vSM, compared to pain controls and healthy subjects, and also reported lower motor function than pain controls. For right-affected CRPS patients only, the deviation of the vSM correlated significantly with the severity of distorted body perception. Results confirm previous findings of impaired visuospatial perception in CRPS patients, which might be the result of the involvement of supraspinal mechanisms in this pain syndrome. These mechanisms might accentuate the leftward bias that results from a right-hemispheric dominance in visuospatial processing and is known as pseudoneglect. Pseudoneglect reveals itself in the tendency to perceive the midpoint of horizontal lines or the subjective body midline left of the centre. It was observable in all 3 groups, but most pronounced in CRPS patients, which might be due to the cortical reorganisation processes associated with this syndrome.