Clinical Research Directory

Patients underwent visual internal urethrotomy using a cold knife at the 12 o'clock position, with additional incisions at the 4 and 8 o'clock positions if needed, until healthy tissue was reached. After the incision, a vial containing 10 mg of mitomycin C was reconstituted with 20 mL of normal saline to obtain a stock solution of 0.5 mg/mL. From this solution, 8 mL was withdrawn and further diluted with 2 mL of normal saline, resulting in a final volume of 10 mL at a concentration of 0.4 mg/mL, giving a total administered dose of 4 mg. Using an endoscopic injection needle, 2 to 3 mL of the prepared mitomycin C solution was injected submucosally per site at the 12, 4, and 8 o'clock positions, with 2 to 3 additional sites injected in some cases, all under direct endoscopic vision at the incised stricture segment. A 20-F silicone urethral catheter was then left in place for 10 days.

Patients underwent visual internal urethrotomy in the same manner as Group A. Platelet-rich plasma was prepared using the double-spin method. A total of 50 mL of whole blood was withdrawn with anticoagulant and centrifuged at 100 g for 15 minutes, then the platelet-containing plasma was collected and centrifuged again at 1600 g for 20 minutes at 22°C. The lower third containing the platelet pellets was collected, yielding about 5 mL of sterile platelet-rich plasma, which was mixed with 5 mL of normal saline to produce a 10 mL solution. Using an endoscopic injection needle, 2 to 3 mL of the prepared platelet-rich plasma solution was injected submucosally per site at the 12, 4, and 8 o'clock positions, with additional sites injected in some cases, all under direct endoscopic vision. A 20-F silicone urethral catheter was then left in place for 10 days.