A new surgical procedure has allowed men with abnormally short penises to enjoy a full sex life and urinate standing up, some for the first time. Tiny "micro-penises" have been enlarged to normal size without losing any erogenous sensation, say UK doctors.

Micro-penis" refers to any penis shorter than 7 centimetres when fully erect - approximately half of the average length (12.5 cm). Approximately one in every 200 men have a micro-penis, either because of a birth defect or because they have undergone cancer treatments. "It's not so much penile enlargement as penile construction," says David Ralph at the University College of London, UK, who will describe the technique on Wednesday at a sexual medicine conference in London. Until now, these men have not been able to have sex or urinate in a urinal because their penis was too short. In the past, flaps of skin from the forearm had been used to reconstruct a penis from scratch, either to physically transform women into men or to replace an amputated penis. But this technique actually fuses the new penis with the existing one so, besides the adding of sheer bulk, erogenous sensation can be preserved. Cylindrical flap Ralph operated on nine men aged between 19 and 43 with a range of medical histories, including three hermaphrodites, two with other birth defects and two whose penises did not develop properly after undergoing chemotherapy as infants. He made three 12.5 cm incisions in the arms of these patients, harvesting a square flap of skin. While it was still attached to the arm he rolled it up "like a Swiss roll" with a tube running down the centre. Ralph then cut off the cylindrical flap and sewed it at one end to the base of the micro-penis - so that original penis ran along the inside of the cylinder. To preserve erogenous sensation, he also cut the tip of the penis - called the glans - away from the main shaft, while leaving the blood vessels and nerves intact. While still being connected to the blood vessels and nerves of the micro-penis, the glans was sewn back to the outside end of the new penis. Arteries, veins and nerves from the pelvis were also joined to supply the new penis. Full sexual function The skin on the arm is perfect, says Ralph, because the blood vessels are about the same size as those in the pelvis and are positioned so that the two can easily be joined together. The arm is restored with a skin graft from the buttocks. But for full sexual function, a penile prosthesis - used frequently by men who have problems achieving an erection - must also be implanted. It consists of a silicone cylinder that lines the penis shaft and is attached via a pump to a silicone reservoir in the abdomen. Pushing a button under the scrotum causes fluid to pass from the reservoir into the shaft, stiffening the penis. "Its certainly a nice gain for the field," says Anthony Atala, a urologist at Wake Forest School of Urology in Winston-Salem, North Carolina, US. No one had ever combined the disconnection of the glans with a skin graft, he says. Transsexuals and amputation victims who have skin transferred from their forearm to the pelvis have no glans to start off with, and so have to manage without erogenous sensation in their reconstructed penis. And patients with abnormally short urethras have had their glans disconnected to undergo a urethra extension, but this had not been combined with a skin graft.