Cost-effectiveness of minimal interventional procedures for chronic mechanical low back pain: design of four randomised controlled trials with an economic evaluation.

BACKGROUND: Minimal interventional procedures are frequently applied in patients with mechanical low back pain which is defined as pain presumably resulting from single sources: facet, disc, sacroiliac joint or a combination of these. Usually, these minimal interventional procedures are an integral part of a multidisciplinary pain programme. A recent systematic review issued by the Dutch Health Insurance Council showed that the effectiveness of these procedures for the total group of patients with chronic low back pain is yet unclear and cost-effectiveness unknown. The aim of the study is to evaluate whether a multidisciplinary pain programme with minimal interventional procedures is cost-effective compared to the multidisciplinary pain programme alone for patients with chronic mechanical low back pain who did not respond to conservative primary care and were referred to a pain clinic. METHODS: All patients with chronic low back pain who are referred to one of the 13 participating pain clinics will be asked to participate in an observational study. Patients with a suspected diagnosis of facet, disc or sacroiliac joint problems will receive a diagnostic block to confirm this diagnosis. If confirmed, they will be asked to participate in a randomized controlled trial (RCT). For each single source a separate RCT will be conducted. Patients with a combination of facet, disc or sacroiliac joint problems will be invited for participation in a RCT as well. An economic evaluation from a societal perspective will be performed alongside these four RCTs. Patients will complete questionnaires at baseline, 3 and 6 weeks, 3, 6, 9 and 12 months after start of the treatment. Costs will be collected using self-completed cost questionnaires. DISCUSSION: No trials are yet available which have evaluated the cost-effectiveness of minimal interventional procedures in patients with chronic mechanical low back pain, which emphasizes the importance of this study. TRIAL REGISTRATION NUMBER: National Trial Register: NTR3531.

Increased endothelin-1 and diminished nitric oxide levels in blister fluids of patients with intermediate cold type complex regional pain syndrome type 1.

BACKGROUND: In complex regional pain syndrome type 1 (CRPS1) pro-inflammatory mediators and vascular changes play an important role in the sustained development and outcome of the disease. The aim of this study was to determine the involvement of vasoactive substances endothelin-1 (ET-1) and nitric oxide (NO) during early chronic CRPS1. METHODS: Included were 29 patients with CRPS 1 who were diagnosed during the acute stage of their disease and observed during follow-up visits. Disease activity and impairment were determined and artificial suction blisters were made on the CRPS1 and the contralateral extremities for measurements of IL-6, TNF-alpha, ET-1 and nitrate/nitrite (NOx). RESULTS: The levels of IL-6, TNF-alpha and ET-1 in blister fluid in the CRPS1 extremity versus the contralateral extremity were significantly increased and correlated with each other, whereas NOx levels were decreased. CONCLUSION: The NOx/ET-1 ratio appears to be disturbed in the intermediate stage of CRPS, resulting in vasoconstriction and consequently in a diminished tissue blood distribution.

Evidence for local inflammation in complex regional pain syndrome type 1.

BACKGROUND: The pathophysiology of complex regional pain syndrome type 1 (CRPS 1) is still a matter of debate. Peripheral afferent, efferent and central mechanisms are supposed. Based on clinical signs and symptoms (e.g. oedema, local temperature changes and chronic pain) local inflammation is suspected. AIM: To determine the involvement of neuropetides, cytokines and eicosanoids as locally formed mediators of inflammation. METHODS: In this study, nine patients with proven CRPS 1 were included. Disease activity and impairment was determined by means of a Visual Analogue Scale, the McGill Pain Questionnaire, the difference in volume and temperature between involved and uninvolved extremities, and the reduction in active range of motion of the involved extremity. Venous blood was sampled from and suction blisters made on the involved and uninvolved extremities for measurement of cytokines interleukin (IL)-6, II-1beta and tumour necrosis factor-alpha (TNF-alpha), the neuropetides NPY and CRGP, and prostaglandin E2 RESULTS: The patients included in this study did have a moderate to serious disease activity and impairment. In plasma, no changes of mediators of inflammation were observed. In blister fluid, however, significantly higher levels of IL-6 and TNF-alpha in the involved extremity were observed in comparison with the uninvolved extremity. CONCLUSIONS: This is the first time that involvement of mediators of inflammation in CRPS 1 has been so clearly and directly demonstrated. This observation opens new approaches for the succesful use and development of immunosuppressives in CRPS 1.