Efectos de la punción seca en la función del sistema nervioso autónomo en sujetos sanosensayo clínico aleatorio controlado a simple ciego

Abstract

Background: One of the possible analgesic mechanisms of the dry needling is the analgesia caused by stress, produced by the activation of the sympathetic nervous system. Although it is known that some techniques as acupuncture produce some changes in the autonomic nervous system, there is still a knowledge gap about the relation between dry needling and the autonomic nervous system. Aim: To determine if the application of dry needling causes the activation of the sympathetic nervous system generating an analgesic effect by stress in healthy subjects. Methodology: A single-blinded randomized controlled trial was performed at the University of Alcalá, involving a sample of 65 healthy volunteer subjects who accomplish the selection criteria, with an average age of 27,78 (DT = 8,41) years, within which the 50,8 per cent are men and the 49,2 per cent are women. The participants have been assigned by random to participate in group 1, to which a deep dry needling has been applied; or in group 2, to which a placebo needling technique has been applied. The intervention technique was applied in the adductor pollicis muscle of the left hand in both groups. In order to evaluate the sympathetic nervous system, the skin conductance, the heart rate, the heart rate variability, the skin temperature and the breathing rate prior have been measured, during and twice after the intervenction; with the biofeedback Nexus 10 MK-II equipment, as well as the salivary cortisol levels before and after the intervenction. The pressure pain threshold has been collected in the adductor pollicis muscle of the left hand and of the right tibialis anterior with a hand algometer, before and after the intervention. Moreover, the pain during the dry needling has been registered through a Verbal Numerical Scale of pain and the elicited local twitch responses. Results: Within both interventions with dry needling an activation of the sympathetic nervous system is produced, behaving in a similar way in terms of measured variables. It has been observed in the deep needling group a significant increase of the heart rate and the pressure pain threshold at central and local levels with respect to the placebo group. Conclusions: It has been registered a hipoanalgesic effect in a short term in healthy subjects, inferring that the dry needling can produce a descendant inhibitory modulating of the pain produced by an inhibitory response of the sympathetic nervous system. More scientific investigation is yet required in order to explain the possible analgesic mechanisms which are produced by the dry needling technique.