Fig. 1.

This decision tree represents the four possible scenarios stemming from the use of the 3-month models. Each outcome, a, b, c, or d, corresponds to a theoretical clinical scenario. For instance, true positives are those in which appropriate surgical treatment is rendered, false positives are those in which unnecessary surgery is performed, false negatives are those in which surgery was inappropriately withheld, and true negatives are those in which appropriate nonsurgical or less invasive treatment is rendered.