In epidemiology, a risk factor is a variable associated with an increased risk of disease or infection. Sometimes, determinant is also used, being a variable associated with either increased or decreased risk.
A history and physical examination, focusing on risk factors for cardiac, pulmonary and infectious complications, and a determination of a patient's functional capacity, are essential to any preoperative evaluation.
see Risk assessment
Duration of surgery together with comorbidity and acquired neurological deficits is an independent risk factor for extracranial complications after brain tumor surgery. Duration of surgery is also associated with surgical site infections. Knowledge about the potential harm of slow surgery should be of interest to neurosurgeons when deciding on various surgical approaches, surgical tools or providing training. Also if acquiring ethical approval or informed consent in technical research projects, the risks associated with prolonging brain surgery should be considered. Special consideration should be warranted in patients with significant comorbidity, planned long surgery and higher risk of acquiring neurological deficits after surgery 1).