Dr. Mark J. Hornyak is a neurosurgeon in Cooperstown, New York and is affiliated with multiple hospitals in the area, including Bassett Medical Center and Cobleskill Regional Hospital. He received his medical degree from University of Maryland School of Medicine and has been in practice for more than 20 years. Dr. Mark J. Hornyak has expertise in treating dementia, spinal stenosis and spondylosis, among other conditions - see all areas of expertise. Dr. Mark J. Hornyak accepts Medicare, Aetna, Cigna, Blue Cross, United Healthcare - see other insurance plans accepted.