We report a case study of cranial trepanation in a male subject 30 to 40 years of age from the Nefteprovod II burial ground in the Anzhevsk archeological site. This burial dates back to the Late Bronze Age, in particular the Karasuk culture located in the Minusinsk Basin on the Yenisei River and on the upper reaches of the Ob River. The left parietal bone had an opening with evident signs of bone healing, as well as signs of inflammatory reaction from both bone plates of the calvarium. The strongest signs of inflammation were located around the trepanation opening at the exocranium, suggesting that it occurred after, rather than before, the operation. Although trepanation was the main cause for the development of the changes noted in the preceding texts, there are no reasons to believe that the subject died from complications arising from infection after trepanation. The patient survived and later died for reasons that may never be determined. Medical necessity was the most likely justification for trepanation. Immersion in altered states of consciousness may also have been a necessary part of the trepanation process as a mode of sedation, along with other shamanic practices, such as consumption of psychotropic substances or ecstatic dance. These data, together with reports of other ante mortem burials, raised questions about the application of anaesthesia and possible techniques of cranial trepanation. These issues and possible postoperative complications are discussed in the following text.