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[Angiological and neurological problems after shunt surgery in haemodialysis patients].

Vascular access induced complications contribute to the morbidity of patients on regular dialysis treatment. Impaired peripheral perfusion, cardiac stress and nerve lesions are the most common of these complications. In the first part of this paper, angiological problems caused by creating arterio-venous shunts are described. Shunt volumes, blood circulation in the shunt arm and shunt-induced alterations of the circulatory blood volume are discussed as well as the conditions under which these parameters gain pathogenic importance. After describing the different shunt-specific circulatory disturbances in detail, the whole spectrum of preventive interventions are discussed. Based on the author's experience during more than four decades in this field, it is strongly recommended to treat even slight but clinically relevant circulatory disorders caused by arterio-venous shunts. The second part of this paper deals with neurological complications in access surgery for dialysis. The pathogenesis of these complications and the measures necessary to avoid them are discussed. Depending on the skin incision, 5 to 20 % of the patients with fistulas between the radial artery and the cephalic vein at the wrist show lesions of the superficial branch of the radial nerve or of the lateral forearm nerve branches. Fistulas with the ulnar artery at the dorsal aspect of the lower forearm frequently cause irritations of the ulnar nerve's superficial palmar branch. Fistulas with the basilic vein in the upper arm often are associated with lesions of the medial cutaneous nerve of the forearm, especially when the vein is "subcuticularized". Aside from these rather benign lesions, sometimes severe sensomotoric functional losses of the median, radial, and ulnar nerves occur, predominantly after implantation of vascular graft shunts in the upper arm. Similar nerve damage can also be observed in association with severe impairment of the peripheral perfusion caused by this type of shunt. Nerve lesions resulting from severe ischemia are rather rare and most often develop in risk patients with preexisting poor peripheral perfusion.