Mr John Yianni is a highly experienced consultant neurosurgeon based in Sheffield who specialises in functional neurosurgery and Gamma Knife surgery, including stereotactic radiosurgery and stereotactic radiotherapy using Gamma Knife. In addition to all aspects of neurosurgery, he is also an expert in the diagnosis and treatment of neurological-related disorders, such as dystonia, tremor and Parkinson’s disease, and has extensive experience with statistical package for the social sciences (SPSS) for complex analysis. Alongside his NHS work at Sheffield Teaching Hospital, Mr Yianni currently sees patients at the widely-acclaimed Thornbury Radiosurgery Centre. Mr Yianni qualified from University College London in 1996, having become a member of the Royal College of Surgeons in 1992. He undertook his basic surgical training in Oxford and then went on to work as a clinical research fellow in neurosurgery with interest in stereotactic functional neurosurgery from 2001 to 2004 and was awarded a doctorate for his thesis. He acquired invaluable experience in this field as well as in framed and frameless stereotaxy. He was later appointed a specialist neurosurgical trainee in neurosurgery from 2004 to 2009 and it was during this time that Mr Yianni became a fellow of the Royal College of Surgeons. He then worked as a fellow in stereotactic radiosurgery and functional neurosurgery and subsequently appointed as a consultant in 2011. With a specialist interest in stereotactic Gamma knife radiosurgery and stereotactic functional neurosurgery, Mr Yianni joined Thornbury Radiosurgery Centre, renowned for its high level of expertise in Gamma knife surgery. Besides his neurosurgery practice, Mr Yianni holds an interest in research and regularly publishes his academic work in scientific peer-reviewed journals. He is also the Neurosurgery Theme Lead at Sheffield Clinical Research and Innovation Office.