Based on investigations of 50 patients with crural ulcer of venous origin divided into groups with ulcers which healed within three months and those which did not heal the authors found that the basic principle of healing is early diagnosis of an insufficient VSM trunk and its subsequent elimination. Duplex sonography revealed the causes of the extent of VSM and VSF, the length of the reflux in both venous trunks, the relationship of their size with age and the grade of reflux shortening after elimination of the insufficient VSM trunk. The size of the VSM as well as VFS increases with advancing age. The authors focused attention on investigations of the length of the reflux in VMand VSF before removal of the insufficient trunk and after removal of VSM during ambulatory phlebectomy. After removal of the trunk the reflux at the saphenofemoral junction disappeared and at the same time reduction of the reflux in VFS occurs. Complete disappearance of reflux in VFS however does not occur. The ratio of insufficient VSM combined with VFS insufficiencies is considered by the authors the most important cause of so-called resistant crural ulcers. To this the time factor must be added, i.e. the longer the insufficiency of the VSM trunk is without treatment, the more extensive and more serious are the disorders of the microcirculation and the slower the healing of crural ulcers.

        Key words: ulcus cruris venosum - treatment - diagnostics - duplex sonography - ambulatory flebectomy.