Penile Curvature Caused By Peyronie’s Disease: What You Need To Know – A Guide To Patients And Urologists.

Important Considerations In Measuring Penile Curvature.

Quality of erection can affect the measurement of penis curvature.  Other factors are also important in determining a treatment plan in addition to penile curvature.

How Is Penile Curvature Measured?

There are a few ways to measure penile curvature.  One option is to use a picture taken by the patient and estimate penile curvature from the picture.  Patient taken pictures are useful for initial evaluation of penile curvature. It allows a urologist to see the severity of curvature and possibly associated abnormalities such as hourglass appearance (penile waist or narrowing in the middle of the penis).    

Android and iPhone Apps have been created in an effort to help measure penile curvature from the picture.

Measurement of curvature from an image may give an accurate measurement but the measurement may be wrong if the erection is not fully hard.

However, it is important to realize that pictures may not accurately represent a complex three-dimensional nature of the curvature and often the associated abnormalities such as hourglass deformity or narrowing of the penile shaft as well as loss of penile hardness may not be appreciated easily from a picture. 

A more traditional and useful way to evaluate penile curvature is by inducing an artificial erection in the office with medications such as prostaglandin or Trimix.

How Precise Is Measurement Of Penile Curvature?

Because the penis is a little bit floppy, it is not easy to get an exact measurement of penile curvature.  As a matter of fact, the same person measuring penis 2 or 3 times he is likely to get different results that vary by 5-10°, depending on where exactly the goniometer (the device used to measure angles) is positioned.

Underestimation of Penile Curvature is Common.

There are a number of reasons why the measurement of penile curvature may underestimate the true severity of curvature are caused by  Peyronie’s disease.

In patients with Peyronie’s disease, there is typically no noticeable curvature when the penis is not erect.  When  the penis gets erect the curvature starts to become noticeable.  Unless the curvature is measured when the penis is fully erect, the curvature will be underestimated sometimes by a significant amount

A severe 90° curvature may appear as only a minor 20-30° curvature if the penis is only 50% erect.  For this reason, it is very important to get an adequate erection that is at least 85-90% hard to fully evaluate the severity of penile curvature.  In addition, secondary and three-dimensional curvature appearance may not be well appreciated if the erection is not full.

In fact, it is not uncommon that patients with severe erectile dysfunction are unable to get an adequate erection with an injection of Trimix in the office. When these patients undergo treatment for erectile dysfunction with a penile prosthesis, often Peyronie’s disease is first recognized intraoperatively during insertion of the penile implant once the implant is inflated during surgery and a curvature is noted.

Key Points: Measurement of Penile Curvature

  1. A full erection is necessary for accurate measurement
  2. Less than full erection leads to underestimation of the severity of penile curvature
  3. 5-10° inter-measurement variation is expected