**Acknowledgement**

We wish to thank our colleagues: Prof. Marek Gacko, Dr Andrzej Guzowski from Department of Vascular Surgery and Transplantology, Medical University of Bialystok and Prof. Zenon Mariak, Dr hab. Jan Kochanowicz from Department of Neurosurgery, Medical University of Bialystok; for cooperation and clinical consultations.
