Efficacy and evaluation of safety of sclerosants for intramuscular venous malformations: Clinical and experimental studies

Excision of intramuscular venous malformations may damage intact functional muscles, and sclerotherapy is an alternative way of relieving symptoms. Several sclerosants are available, but selection of the optimal one is controversial. We report our clinical experiences of sclerotherapy, and experimental studies in rats that investigated muscular damage after injection of various sclerosants. For the clinical study, 10 patients with intramuscular venous malformations were reviewed who had been treated by sclerotherapy using ethanolamine oleate. The rate by which the volume reduced was assessed quantitatively using findings from magnetic resonance imaging (MRI). Pain was cured or improved in all cases, and volume reduced on imaging analysis. There were no severe complications such as renal failure or thromboembolism. For the experimental study, 62 Wistar rats were used to investigate the toxicity of sclerosants on the intact-muscle by injecting three types of sclerosants (100% ethanol, 5% ethanolamine oleate, and 1% polidocanol). After the injection of each sclerosant into the anterior tibial muscle, the daily measurement of the circumference of the legs, histological and morphological alterations in the muscles, and maximal isometric tetanic tension, were investigated. Swelling was most prominent with ethanolamine oleate, while destruction and atrophy of the muscle were most prominent after injection of ethanol. In the clinical study, the efficacy of 5% ethanolamine oleate was at least equivalent or possibly superior to that of 100% ethanol. In the experimental study, ethanol had a more detrimental effect on muscles than the other agents. We consider that ethanolamine oleate is the most suitable sclerosant for the treatment of intramuscular venous malformations.