Nocturnal Penile Tumescence and Rigidity testing (NPTR)
I got a call yesterday from a gentleman in his early thirties. Do you do RIGISCAN doctor? ‘He asked’. I said “but what is your problem”? I have features suggestive of Erectile Dysfunction (ED) and I have been asked to get a Rigiscan done. The Rigiscan has become so popular that patients without any knowledge of the pathophysiology and risk factors leading to ED want to get tested. So what is the Rigiscan and do you really need it?
I have stated in my previous blogs that Erectile Dysfunction is the inability to maintain a penile erection sufficient for sexual intercourse. ED can either be Psychogenic or Organic in origin. In organic ED there are neurogenic and vascular causes. In order to differentiate neurogenic and physiologic ED, a rigiscan is used.
The RigiScan, has two loops, one to be placed around the base of the penis and the other towards the tip, that tighten every fifteen or thirty seconds. The recording unit can be strapped around the waist or thigh.
In order for the rigiscan to get done it is important the patient gets admitted over two to three nights at the hospital. A single night may give false positive results and is usually unacceptable. A home based test is also available but most physicians prefer to do it at the hospital.
Different theories have been proposed to explain NPTR. It would however suffice to say that NPTR is needed for normal penile health. A Normal NPTR rules out a neurogenic cause of ED.
After the advent of PDE5 inhibitors physicians have questioned different testing techniques as most treatment remains the same. Also the cumbersomeness of the procedure (2-3 nights in the hospital) and less than perfect results have resulted in the popularity of the Rigiscan waning.