Laird Harrison

May 20, 2013

SAN DIEGO, California — Not every man wants a bit of cow grafted to his penis, but hundreds of patients have found the experience satisfying, a new study shows.

"This xenograft has advantages over allografting," Joon-Yung Kim, MD, a surgeon at Philip and Paul Medical Group in Seoul, Korea, told Medscape Medical News.

He presented his study findings here at the American Urological Association 2013 Annual Scientific Meeting.

The relatively new penis augmentation procedure might help patients with injured or concealed penises, epispadias, and Peyronie's disease, said Dr. Kim.

In addition, he offers the procedure to men with psychological and sexual complexes caused by their small penises.

In a series of 1095 xenografts, Dr. Kim treated 1 man with hypogonadism, 18 with penis injuries, and 1076 who wanted the surgery for cosmetic reasons.

He performed the surgery only after careful discussion with the patient about penis size, level of sexual and social satisfaction, expectations, and the risk for complications.

Dr. Kim used type I collagen (Lyoplant, Braun), which is extracted from bovine pericardium, which has been approved by the US Food and Drug Administration for neurosurgical dural replacement. It is absorptive and multiparous, which enables it to combine quickly with human tissue, said Dr. Kim.

Bovine Pericardium

Dr. Kim cut the graft matrix to fit the patient's penis in about 4 to 6 layers, then made several transverse and vertical slits, more of which were on the inner side of the incised graft.

He found that making a mesh structure with these slits provided better flexibility in the implant, reducing nocturnal erection pain and edema.

With the patient under local anesthesia, he exposed the Buck's fascia and dissected the subdermal tissue of the prepubic area. He then incised and affixed a fundiform or suspensory ligament.

After separating the glans from the tunica albuginea, he inserted and affixed the enhancement tissue. To increase girth, he affixed additional tissue to the Buck's fascia.

Many patients had temporary swelling and rubefaction, but a light compression dressing relieved these symptoms in most cases.

Twenty-six men (2.4%) required active treatment. Of these, 18 infections required graft removal. There were 5 cases of wound dehiscence, 2 of hematoma, and 1 of penile curvature.

Some patients asked for additional augmentation, which gave Dr. Kim an opportunity for a histologic examination in 5 cases. He found that the patient's own tissue had replaced the implanted collagen tissue in most cases. The patients had grown not only connective tissue, but new vessels.

Dr. Kim finished his presentation by putting xenografts in the context of other approaches. Grafting autologous dermal fat has the advantage of early augmentation and less foreign-body sensation. However, it leaves a scar and involves a longer operation. In addition, the fat might be quickly absorbed.

Injecting autologous fat reduces the scarring, but can create an unnatural shape, he explained. Fat cysts and granulomas can result.

"Many doctors prefer allografts," said Dr. Kim. Allogenic dermis grafts have the advantages of no harvest scar and a shorter operation time. However, it is expensive, he pointed out, and using donated tissue for a cosmetic purpose raises ethical questions.

"Xenografts have less disadvantages after surgery," said Dr. Kim. Xenogenic grafts are about one third the cost of allogenic grafts, he noted, and only about 10% to 30% of the tissue is absorbed. The main downside is a foreign-body sensation, but this passes with time, he said.

"I'm not aware of anybody else who does xenografts," said session moderator Kenneth Angermeier, MD, from the Cleveland Clinic in Ohio. "It seemed to work for him," he told Medscape Medical News.

Perhaps the most important question is how patients are selected, Dr. Angermeier said. "Who are the patients who will benefit?"

This study received no outside funding. Dr. Kim and Dr. Angermeier have disclosed no relevant financial relationships.

American Urological Association (AUA) 2013 Annual Scientific Meeting: Abstract 18. Presented May 4, 2013.


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