Patient records constitute an important source of valuable information for health-care personnel. Unfortunately, however, in most health-care institutions these are not indexed and organized to support decision-making. A patient record is complex and has data on so many parameters that conventional methods are not capable of fully exploiting the information and knowledge in these. This paper reports the initial results of an ongoing experiment to build an ontology based on concepts extracted from the patient records in the domain of neurosurgery of a large hospital. Results suggest that the ontology could prove to be an acceptable way of providing a decision support system for health care personnel.