A controlled, single-blinded study of acupuncture vs. sham acupuncture on epicondylopathia humeri radialis
N.Behrens(2), H. Karg(2), D.Irnich(1), J.Gleditsch(1), M.A. Schreiber(3), P. Kroling(2)
(1)Institute for Anaesthesiology, (2)Clinic for Physical Medicine,(3)Institute for Med. Biometrics (IBE), Klinikum Grobhadem, University of Munich, Germany
In a prospective study 50 patients with epicondylopathia humeri radialis (duration of pain 1 month to 1 year) were randomly divided into 2 groups. In one group 5 classical acupuncture points were used. In the other group needling was carried out at theoretically irrelevant, non-classical sites with the same depth of insertion and stimulation. The patients were blinded. They did not know, if they were treated by real or by sham acupuncture. 3 treatments were performed every third day. Outcome measures included a pressure algometrie, which indicates the pain pressure threshold (kgIcm2) on 2 defined tender points (P1= tendon of m. extensor carpi rad. on the elbow, P2= distal point on the m. ext. carpi radialis) and a vigorimetre. which measures the pain threshold while making a fist. The patients were assessed by an independent (blinded) examiner before and immediate after the first treatment, immediate after the third treatment and 14 days after the third treatment.
The mean difference was calculated between the first and the second evaluation (immediate effect), between the first and the third evaluation (effect after 3 treatments) and between the third and the fourth assessment ( 14 day follow-up). The Wilcoxon Signed Rank Test, adjusted acc. Bonferroni was used for the data of pressure algometre. The data of vigorimetre were analyzed by using the Paired Sign Test.
In the real acupuncture group the pain threshold improved significantly from 3,18 (P1) and 3,10 (P2) to 3,46 (Pl,P2) immediate after the first treatment. After the third treatment there was a significant improvement to 4,08 (P1)/ 4.10 (P2), which still improved after 14 days follow-up to 4.42 (Pl)/ 4.46 (P2).
In the sham acupuncture group there was also a significant improvement regarding the values before and immediate after the treatment (P 1: 2, 68 to 2, 84; P2 : 3, 46 to 3,69) and after the third treatment (Pl: 3,31; P2: 4,03), but it was less strong than in the real acupuncture group and there was no more improvement 14 days after the third treatment (Pl: 3,34; P2: 4,02). The values for the vigorimetre were similar.
The result suggests that sham acupuncture has a short-term pain relieving effect, which could be explained by the diffuse noxious inhibitory controls (DNIC). In this case the better results, especially the middle-term effect, of real acupuncture could be explained by specific effects, but this hypothesis is still to be proven.