Noninvasive methods of diagnosing bladder outlet obstruction in men. Part 2: Noninvasive urodynamics and combination of measures

Purpose: Many methods have been suggested to diagnose bladder outlet obstruction, as defined by the gold standard of pressure flow studies. Difficulty arises when comparing completely different methods of diagnosing bladder outlet obstruction. A comprehensive review of the literature on the different methods used to diagnose bladder outlet obstruction by noninvasive means was performed with a view to allow such a comparison. Materials and Methods: A MEDLINE search was done of the published literature covering until the end of 2004 on noninvasive methods, including single measure and combinations of measures, to diagnose bladder outlet obstruction. A direct comparison of all of the different methods was made using the sensitivity, specificity, likelihood ratio, and pretest and posttest probability of diagnosing bladder outlet obstruction for each test. For many techniques these values were calculated from the data presented in the article. Results: A multitude of methods has been applied to diagnose bladder outlet obstruction. Broadly the methods were divided into nonurodynamic and noninvasive urodynamic methods. Nonurodynamic methods were considered in part 1 of the review. Part 2 considered noninvasive urodynamic techniques, such as uroflowmetry, the penile cuff, the condom method and Doppler urodynamics. A combination of single measures was also considered and the relative merits of these approaches were discussed. Conclusions: A combination of noninvasive urodynamics and ultrasound derived measures provide promising methods of diagnosing bladder outlet obstruction. However, pressure flow studies still remain the gold standard for assessing bladder outlet obstruction.