片側反回神経麻ひに対するシリコン注入治療 基礎と臨床

Abstract

Silicone injections for unilateral recurrent laryngeal nerve (RLN) paralysis became popular in Japan over a decade because of easy and simple technique, although Teflon injections are more favoured in other countries. In contrast to more solid type which has been shown to stay longer and safer in a tissue, silicone of more fluid type is regarded as useless simply because it is believed to be finally absorbed in a tissue.An attempt was made, therefore, to critically investigate not only biological reactions of a surrounding tissue against injected silicone of fluid type, but either long-term stay in a tissue or eventual disappearance. This project was conducted first in the animal experiments and secondly in 37 appropriately selected human cases with unilateral RLN paralysis. They were followed up from half a year to 9 years postoperatively.Results of animal experiments delineated long-term stay of silicone covered by fibrous capsule in 38 thigh muscles out of totally 46 muscles of 23 rat to figure a success rate of as high as 83 per cent. Only 8.7 per cent was found as being absorbed.Autopsies of these animals disclosed presence of a fibrous capsule containing silicone of fluid type therein without any other associated pathological changes.In 37 human cases, silicone injections showed long-term effectiveness upon voice improvement, apparent prolongation of maximum phonation time, complete glottal closure on phonation, straightness of the previously bowed vocal fold and also increased thickness of the paralyzed cord. Overall success rate was as high as 81 per cent.