Objective: To determine if written preoperative warnings about risks and outcomes of surgery improves patients' recall and recognition of these warnings postoperatively compared to traditional verbal warnings and to determine if the timing of these warnings is significant.
Design: Prospective study of patients given written warnings compared to a control group of patients warned in the traditional verbal way.
Setting: Oral and Maxillofacial unit of a District General Hospital.
Subjects: Patients undergoing removal of third molars under general anaesthesia.
Main outcome measures: Patients' recall and recognition of warnings about pain, swelling, trismus and lingual and labial dysaesthesias given before surgery for removal of third molars.
Results: Written information significantly improves patients recall and recognition of important warnings such as the risk of dysaesthesia of the tongue (p < 0.001) and lip (p < 0.01) when compared with just verbal warnings. It seems to make no difference if this information is given to the patient a week before on a preadmission clinic or on admission.
Conclusions: Written preoperative information about routine operations would improve the quality of the informed consent process.