He graduated from the School of Medicine at the University of Zagreb in 1997 and started his specialization in neurosurgery in 2001. In 2007, he successfully passed the specialization exam in neurosurgery, and in 2006, he defended his doctoral dissertation on the comparison of the immunoreactivity of epidermal growth factor receptors (EGFR) and proliferation factors (MIB-1) in malignant gliomas of the brain.
He has gained international experience in neurosurgery through various training and fellowship programs, including an epilepsy surgery fellowship at the Clinic of Neurosurgery, University of Bonn, Germany, under the supervision of Prof. Dr. Sc. Johannes Schramm, funded by the Deutscher Akademischer Austausch Dienst-DAAD. In 2010, he passed the European Board Examination in Neurosurgery, becoming the only neurosurgeon in Croatia with this certification.
Apart from his clinical work, Dr. Sajko is actively involved in medical education and research. He has published numerous scientific and professional papers, including original research articles published in reputable journals such as Current Contents, Scopus, and SCI-Expanded.
Dr. Sajko is also a member of several professional associations, including the Croatian Society of Neurosurgery, the Croatian Vertebrology Society, and the Croatian Society for Spinal Surgery. He is one of the founders and the secretary of the Southeast Europe Neurosurgical Society (SeENS).
