The capability for discrimination of vibratory stimuli of the sole of the foot was tested on 12 subjects (6 men, 6 women). Two vibratory stimuli (sinusoidal impulse: frequency, 200 Hz; amplitude, 0.1 mm; duration, 2 sec) were applied at different sites to the sole of the foot. Subjects were asked whether they detected one or two vibratory sensations. The discrimination threshold was defined as the shortest distance at which two vibrations can be differentiated at repeated trials. In addition, the absolute threshold was measured by one plunger (sinusoidal vibration: frequency, 200 Hz; variable amplitude). The values of the absolute threshold (average value, 1.2 microns) were in accordance with the results of other authors. A decrease of discrimination capability was observed along the longitudinal axis of the foot from distal to proximal parts and was about 15 mm at the big toe and 34 mm at the heel. Discrimination at the medial longitudinal arch was inferior to that at the lateral longitudinal arch. This was also true for inverse vibration in which all subjects showed lower thresholds. No relationship was found with respect to thickness of the skin (measured by ultrasound), side of foot, or gender. Determining factors for vibratory threshold might be the density of the Pacinian corpuscles per cm2 as well as their peripheral and central representation. Anatomical or physical factors (e.g., thickness of the skin, impedance of the deeper tissue) can probably be disregarded.
Crural ulcers represent the most serious form of chronic venous incompetence (CVI). According to duplex studies superficial venous incompetence predominate in this stage of the disease, but combined refluxes of superficial and deep veins are also common. Despite a positive correlation between the number of incompetent perforators and the stage of CVI isolated incompetence of perforating veins in venous ulcers are rarely found. Additionally, only a minority of incompetent perforators depict larger reflux volumes. Therefore, doubts about a causal role of perforators incompetence in ulcer genesis are justified. According to phlebodynamometric studies the risk of crural ulcer development increases with the degree of hemodynamic compromise. Ulcer healing can only be achieved after complete normalization of ambulatory venous hypertension. In case of superficial refluxes and concomitant incompetence of perforating veins exclusion of the superficial component is sufficient to achieve this goal. Incompetent perforators normalize their function consecutively. In contrast, venous hypertension persists after exclusion of superficial refluxes in case of incompetent perforators and irreversible damage of the deep venous system. Surgical therapy studies exactly reflect the results of these hemodynamic examinations. Therefore, the role of endoscopic subfascial perforator dissection (ESPD) in the treatment of venous ulcers remains unclear. Future therapy studies should take into account that the definite role of ESPD in ulcer healing can only be examined without additional treatment of refluxes in the saphena system. Additionally, all study patients should be classified according to the CEAP nomenclature and Hach's classification of chronic compartment syndrome. Methodological differences in technique and extent of ESPD have also to be taken into account.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.