A comparison of incidences of bladder neck contracture of 80- versus 180-W GreenLight laser photoselective vaporization of benign prostatic hyperplasia

Bladder neck contracture (BNC) after GreenLight laser photoselective vaporization (PVP) of benign prostatic hyperplasia is a common complication. In the present study, data of patients received 80 or 180 W PVP were collected. Perioperative parameters, including applied energy, irradiation time, catheter removal time, and hospital stay, were recorded. Postoperative parameters, including maximum urinary flow rate, International Prostate Symptom Score, post-void residual volume, and incidences of BNC, were recorded at 3 and 12 months after operations. Bladder neck tissues were taken at 3 months after operations for immunohistochemical staining and western blot analysis to examine the expressions of collagen I, matrix metalloproteinase-3 (MMP-3), and transforming growth factor-β (TGF-β). Sample size of patients was calculated with a power of 80 %. Chi-square test and one-way analysis of variance were performed as statistical methods. Three hundred twenty-six patients who received potassium titanyl phosphate (KTP) laser and 256 who received X-ray photoelectron spectroscopy (XPS) laser entered into the study. Perioperative parameters were comparable, except for shorter irradiation time in 180 W group (P = 0.032). Postoperative parameters were also similar, except for higher incidence of BNC in 80 W group at 3 months after operations (P = 0.022). Immunohistochemical staining and western blot analysis showed higher expressions of collagen I, MMP-3, and TGF-β in 80 W group than in 180 W group. In conclusion, 80 W GreenLight laser showed a comparable efficacy with 180-W laser in PVP but showed a higher incidence of BNC in short term, which might be the result of up-regulated fibrotic factors in bladder neck triggered by lasers.