Influence of specific rehabilitation programs on pressure pain thresholds in patients with fibromyalgia or chronic low back pain

Background: Specific rehabilitation programs are recommended in chronic pain syndromes. The subjective experience and multidimensional nature of pain is problematic for assessment. Pressure pain threshold (PPT) is defined as the minimum force applied which induces pain measured with a dolorimeter.
Objectives: The purposes were: (1) to compare PPTs for 18 specific tender sites in patients with fibromyalgia (FM) and in patients with chronic low back pain (CLBP), (2) to assess the PPT changes in these groups following specific rehabilitation programs.
Methods: Eleven women with CLBP and six women with FM were included in this study. They attended biweekly specific multidisciplinary rehabilitation sessions for 8 weeks. Pain intensity and PPTs for the 18 specific tender sites defined by the American College of Rheumatology were evaluated respectively with a visual analogue scale (VAS) and with an electronic dolorimeter, before and after the programs. Normative data of PPTs were established in a recent study [1].
Results: Before starting the rehabilitation program, patients with FM displayed VAS scores higher (p<0.05) than those with CLBP. Furthermore, FM patients had the lowest (p<0.05) PPTs over all examined areas. Statistical analysis failed to show any differences between PPTs of CLBP and healthy subjects. At the end of the specific program, VAS scores decreased significantly in both patient groups. In contrast, a significant increase of PPTs was only observed in FM patients. However, their PPTs remained below the CLBP and healthy PPT values.
Conclusion: Despite the presence of chronic pain in these two syndromes, the decrease of PPTs appears to be specific in patients with FM. Measure of PPTs could represent a relevant method in order to perform a longitudinal follow-up of patient's pain perception. After the rehabilitation programs, pain intensity decreased in both patient groups.
References: [1] Maquet D, Croisier JL, Demoulin C, Crielaard JM. Pressure pain thresholds of tender point sites in patients with fibromyalgia and in healthy controls. Eur J Pain, 2004, 8:111-117.