Analysis of outcome after thermotherapy using different classifications of bladder outlet obstruction

The urodynamic profiles of 97 patients with benign prostatic hyperplasia undergoing low-energy transurethral microwave thermotherapy (TUMT) for lower urinary tract symptoms were analysed using the Abrams/Griffiths nomogram, the urethral resistance algorithm, the linPURR, Schäfer nomogram, and the CHESS classification. A significant clinical response was seen for the whole group, as shown by changes in symptom score, free flow rate, and residual urine. The best symptomatic response was identified in patients in whom obstruction was present, whatever the classification used. Only the two-dimensional CHESS classification was found to predict a group of patients with a better response in both symptoms and objective variables. Obviously, a better response from TUMT can only be predicted by a classification system that identifies the independent variables of footpoint and slope of the PURR. The CHESS classification was the only one of those studied that satisfactorily identified these two parameters and could be used as a system of case selection for this minimally invasive treatment.