NEW CONCEPT OF BPH - PCAR THEORY

BACKGROUND. A new concept of the pathophysiology of benign prostatic h yperplasia (BPH), based upon the presumed circle area ratio (PCAR) the ory, is described. METHODS. The PCAR is the ratio of the area of the m aximum horizontal section of the prostate by transrectal sonography to the area of a presumed circle of which the circumference is equal to the circumference of the maximum horizontal section. This evaluates ho w closely the shape of the section approaches a circle. RESULTS. A cle ar borderline was found at a PCAR of 0.75 in the postvoiding residual urine volume (PVR) in many cases of BPH. Cases with the PCAR below thi s level almost entirely showed a PVR below 30 mi, while cases with the PCAR over this level demonstrated a wide distribution of PVR. CONCLUS IONS. Such a variety of PVR in cases with the PCAR over 0.75 could be explained by the difference of the elasticity of the surgical capsule (peripheral zone) in each case, which was confirmed by a stress-strain test on extirpated specimens from the capsule at surgery. We develope d a new clinical parameter called the prostatic pressure coefficient ( PPC) to check elasticity, by means of a special balloon catheter inser ted into the prostatic urethra. (C) 1998 Wiley-Liss, Inc.