MODEL RELEASED. Endoscopic prostate surgery. Image 6 of 7. Greenlight HPS laser machine in use during prostate surgery. The laser is inserted into a male patient's urethra, the tube that carries urine from the bladder out of the body, to treat benign prostatic hyperplasia (BPH). BPH is a non- cancerous enlargement of the prostate gland. The prostate surrounds the urethra, just beneath the bladder. BPH has caused a narrowing of the urethra and a difficulty passing urine. The laser is vaporising the prostate cells and so widening the urethra. This is minimally invasive, or keyhole, surgery and requires minimal aftercare. It does not cause bleeding as the heat from the laser cauterises any blood vessels that are hit. For a sequence showing the surgery see M440/211-/217.