[Shape memory alloy spiral for urethrostenosis caused by benign prostatic hyperplasia].

The nitinol (shape memory alloy, SMA) spiral was used in 39 patients with benign prostatic hyperplasia (BPH). Caine experiment indicated that the spiral could be embedded by prostatic urethra epithelium in 6 months. The new transitional epithelium between spiral wires was originated from the urethra transitional epithelium as proved by immunohistochemical staining. The parts of spiral project over the bladder cavity formed incrustation on the spiral tip. The nitinol is of super-elastic property, corrosive-resistance and excellent biocompatibility, in addition to unique shape memory effect. We treated 39 patients with BPH by self-made coaxial sheath introducing Chinese nitinol spiral into the prostatic urethra, with a successful rate of 89.7%. Follow-up for 3-26 months showed no incrustation and migration of the spiral.