It’s normal for a penis to curve a little when it’s erect, but Peyronie’s disease pushes that curve to alarming extremes. It doesn’t usually muck with a guy’s ability to get it up, but once the penis is erect, it can deviate 30° or more from its normal line of action. The curvature can be so severe it interferes with intercourse. Plus, it usually hurts.
The curve is caused by a buildup of scar tissue on one side of the tunica albuginea, the connective tissue wall that surrounds the erectile tissue. Everything looks pretty normal when the penis is flaccid. But when the erectile tissues fill with blood, the scar tissue doesn’t expand as much as the normal wall tissue. One side of the penis winds up shorter than the others, so the tip of the penis bends toward its shortest side. It’s simple physics. Depending on where the scar tissue is, the penis may curve upward, downward, or to one side.
Where that scar tissue comes from is still something of a mystery. Many urologists suspect it’s left over from a penile injury. But most patients can’t remember hurting themselves before they started showing symptoms, and you’d think that would be memorable. That makes some researchers think that the scar tissue could be the cumulative effect of lots of repetitive small injuries rather than the result of one big one. Each injury breaks tiny blood vessels inside the tunica albuginea, and the bleeding and swelling triggers a localised cascade of scar tissue formation. The development of the scar tissue plaque is painless because the tunica albuginea doesn’t contain sensory nerves. Other urologists think that Peyronie’s could be caused by an autoimmune condition that attacks cells inside the erectile tissue, causing swelling and making scar tissue.
In either case, genetic factors seem to play a part: the tendency to develop Peyronie’s seems to run in some families. Age also plays a role — the condition is most common in men over the age of 50. While it’s not life-threatening, 50-80% of Peyronie’s patients say they’re having emotional problems, and who can blame them.
Some Peyronie’s patients get better on their own. But for up to 80% of the men who develop the condition, the pain goes away, but the curve does not. Options for restraightening the shaft of the penis are limited; in the past, doctors have tried lots of different ways to break up the scar tissue, including injections of vitamin E, or omega-3 fatty acids, estrogen blockers like tamoxifen, doses of high-energy radiation, or blasts of sound waves. They have also tried putting the penis in traction devices to straighten it out. But a comprehensive review of clinical studies published this year found no evidence that any of these treatments had any real effect on the plaque.
One treatment that seems to help some Peyronie’s patients is injections of an enzyme called collagen clostridium histolytic directly into the scar tissue. The enzyme, marketed as Xiaflex in the US and Xiapex in Europe, breaks the collagen fibres in the plaque into smaller pieces and partly restores the tissue’s ability to expand. It works best in men with relatively small penile curves, and only if the scar tissue hasn’t started to calcify.
For some patients, only surgery is going to straighten things out. If the patient’s penis has less than a 60° curve, a surgeon can either remove divots of tunica albuginea on the side of the penis opposite the plaque or restrict its expansion with sutures. Both methods effectively shorten the longer side of the penis. Once it heals, the penis as a whole is slightly shorter when erect, but the erect shaft is straight.
If the curve is more severe, the surgeon may instead cut across the plaque to open up the scar tissue and fill in the open space with a tissue graft. This surgery also lets the penis lengthen evenly, but has a much larger chance of damaging erectile function.
[Sources: Martinez et al. 2012 [Gelbard et al. 2013 [Cavallini and Paulis 2015 [Levine and Larsen 2015 [Nehra et al. 2015]]
Contact the author at diane@io9.com. Top image iprachenko via Shutterstock. Penis with Peyronie’s curvature from Peyronie via Wikimedia.
