• Nina Kumowski, Tobias Hegelmaier, Jonas Kolbenschlag, Tina Mainka, Beate Michel-Lauter, and Christoph Maier.
• Department of Pain Medicine, BG University Hospital Bergmannsheil GmbH, Ruhr University, Bochum, Germany.
• Pain Pract. 2019 Feb 1; 19 (2): 168-175.

BackgroundThe early phase of complex regional pain syndrome (CRPS) is characterized by an inflammatory state and therefore often treated with anti-inflammatory acting glucocorticoids. Recently, we demonstrated that remote ischemic conditioning (RIC), a cyclic application of nondamaging ischemia on a remote extremity, reduces blood flow and increases oxygen extraction in the CRPS-affected extremity.AimThe aim of the presented study was to analyze the effect of short-term pain treatment including glucocorticoid pulse treatment on the RIC-induced perfusion parameters.MethodIndependently from the study, pain treatment was started with an oral glucocorticoid pulse (180 to 360 mg prednisolone) in 12 patients with CRPS (disease duration < 1 year). RIC was conducted before and after pulse treatment. Three cycles of 5 minutes ischemia and 10 minutes reperfusion were applied to the contralateral limb. Blood flow, tissue oxygenation, and oxygen extraction fraction were assessed ipsilateral before and during RIC. Current pain was assessed on the numeric rating scale (0 to 10), and finger-palm distance was measured.ResultsPain level (5.8 ± 1.5 vs. 3.1 ± 1.1) and finger-palm distance (5 ± 1.9 cm vs. 3.7 ± 1.9 cm) were decreased significantly by the treatment. RIC decreased blood flow by 32.8% ± 42.8% (P < 0.05) and increased oxygen extraction fraction by 8.5% ± 10.3% (P < 0.05) solely before the treatment. After treatment, all parameters remained unchanged after RIC (P < 0.05 vs. before), comparable to healthy subjects.ConclusionConfirming previous results, RIC presumably unmasks luxury perfusion in untreated CRPS patients. In accordance with the clinical improvement, the short-term pain treatment with glucocorticoids as major component normalizes impaired perfusion. These results might underline the rationale for anti-inflammatory treatment in early-phase CRPS.© 2018 World Institute of Pain.

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