Utility of a generic risk prediction score in predicting outcomes after orofacial surgery for cancer

Understanding how variations in individual patients and perioperative events alter risk is fundamental to a useful audit of outcome. Many surgical scoring systems have been developed to allow for case-mix adjustment when reporting outcome data. To our knowledge this is the first report of the use of the physiological and operative severity score for the enumeration of mortality and morbidity (POSSUM and P-POSSUM) by a maxillofacial unit. We audited 360 operations in 245 patients between 2005 and 2008. The POSSUM morbidity equation showed reasonable discrimination (C Statistic 0.74), as did the P-POSSUM mortality equation (C Statistic 0.75), but neither showed a significant degree of goodness-of-fit (morbidity p=0.0001; mortality p=0.019). Analysis of subgroups of all elective and major operations showed no improvement in the accuracy of scores used to identify risk of complications. The need for a standard of care index for the audit of mortality and morbidity in major head and neck surgery has not yet been met.