Background of the study: CRPS type-1 is a pain syndrome that usually develops after an initiating noxious event (e.g. fracture) in an extremity. Although treatment options life dimethyl-sulphoxide (DMSO), N-acetylcysteine (NAC) and intensive physical therapy exist, the treatment effect is often unsatisfactory, even leading to amputation of the extremity. Surgical treatment of chronic pain disorders by dividing the sympathetic chain is an established treatment. Its more invasive nature has prevented widespread application. After introduction of minimal invasive techniques in recent years, the UMCG has now devised a truly minimal invasive, yet safe and effective thoracoscopic technique, that requires only a single 1 cm long incision in the anterior axillary line. This technique is developed as treatment for primary focal axillary and palmar hyperhidrosis, and is performed in over 50 patients producing very satisfying results. This fact has led to the hypothesis that this same surgical technique can offer this group of chronic pain patients a safe, effective treatment modality.