The Effects of Pulsed Electromagnetic Stimulation on Functional Recovery Following Laryngeal Reinnervation in the Rat / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Ideal treatment for vocal cord paralysis is to restore normal movement of the vocal cord and to bring back the natural voice. Pulsed electromagnetic stimulation (PEMS)has been known to bring early nerve regeneration as well as better functional recovery. The purpose of this investigation is to learn the effect of PEMS on regeneration of the recurrent laryngeal nerve. MATERIALS AND METHOD: Using 36 healthy male Sprague-Dawley rats, we made transections on their left recurrent laryngeal nerves and performed primary anastomosis under the operating microscope. Rats were divided into an experimental group and a control group, each having 18 rats by random sampling. For the experimental group, PEMS was carried out three hours a day and five days a week for twelve weeks. For the control group, PEMS was not given while other conditions were kept the same as in the experimental group. The extent of functional recovery was observed for each group by performing videostroboscopic examination once every week. After twelve weeks, a test for the functional recovery was performed electrophysiologically through laryngeal electromyography during respiration. RESULTS: After the twelve-week experiment, 14 out of 18 rats survived in the group which received PEMS while 8 out of 18 rats stayed alive in the control group. Ten rats (71%)in the PEMS performed group and 3 rats (38%)in the control group showed recovery of vocal cord movement, but it did not reveal any significant difference statistically. However, the time it took for functional recovery was 3.93+/-0.27 weeks and 7.87+/-0.85 weeks for the PEMS performed group and the control group, respectively. And the difference was statistically significant. CONCLUSION: This investigation confirmed the efficacy of PEMS on the early functional recovery in rats with surgically transected and reanastomosed recurrent laryngeal nerve. Further studies to understand the mechanism of action of these effects as well as the local stimulation rather than the total body stimulation seem to be necessary.