CHESS CLASSIFICATION OF BLADDER-OUTFLOW OBSTRUCTION - A CONSEQUENCE IN THE DISCUSSION OF CURRENT CONCEPTS

The present discussion on the natural history, growth rate, pathophysi ology, morbidity, and possible treatment of benign prostatic hyperplas ia (BPH) reinforces the need to objectify mechanical BPH-induced obstr uction with pressure-flow study. Different methods for the quantificat ion of BPH-induced obstruction exist and the grade of simplification d epends on their working mechanism. To review the limitations of the cu rrent concepts, 118 BPH patients were selected for computerized pressu re-flow data analysis according to quadratic passive urethral resistan ce relation (PURR) function. The CHESS classification differs from all other concepts due to its two-dimensional character and was developed as a result of the following way of thinking: (1) the whole individua l pressure-flow plot is the most accurate basis for further analysis; (2) PURR as the true low-pressure flank of the individual plot is the most favorable definition for mechanical obstruction; (3) PURR quantif ication requires at least two parameters, footpoint and curvature/slop e, with regard to the documented missing significant correlation of bo th; and (4) a two-parameter-based classification is two-dimensional (C HESS classification).