Urethral pressure reflectometry; a novel technique for simultaneous recording of pressure and cross-sectional area: a study of feasibility in the prostatic urethra


Mikael Aagaard, Rigshospitalet, Urologisk Klinik D, Blegdamsvej 9, 2100 Copenhagen, Denmark. e-mail: mikael_aagaard@hotmail.com


Study Type – Diagnostic (case series)

Level of Evidence 4

What's known on the subject? and What does the study add?

In the 1980s and 1990s, a method for direct measurement of pressure and cross-sectional area in women and men was developed. It was successful in terms of obtaining meaningful results in several studies. But the technique, which was based on the field gradient principle, was never implemented in the clinical setting because of technical limitations. In 2005, urethral pressure reflectometry was introduced as a new technique in female urodynamics. The technique has been shown to be more reproducible than conventional urethral pressure profilometry, when measuring incontinence in women. In 2010 it was also introduced as a new measuring technique in the anal canal.

This study, adds a new and interesting technique to the field of male urodynamics. For the first time, sound waves have been used to measure pressure and cross-sectional area simultaneously, directly in the prostatic urethra. The results from this first trial with urethral pressure reflectometry are promising, in terms of obtaining meaningful physiological parameters. Our hope is that, future trials will help us to be able to identify specific areas of obstruction or rigidity in the prostatic urethra, making treatment more direct and side effects from surgery less severe. However, further studies are needed to evaluate the technique with regards to clinical usefulness in men with benign prostatic obstruction.


  • Urethral Pressure Reflectometry (UPR) was introduced in 2005, and it has since been used in the female urethra for simultaneous measurement of pressure (P) and cross-sectional area (CA). It has shown to be more reproducible than conventional pressure measurement and reintroduced direct measurement of pressure and elastance in the urethra as important parameters when assessing incontinent women.
  • To test the feasibility of UPR in the prostatic urethra.


  • We tested the technique in ten male patients, median age 73 and range 51–91.
  • Measurements were performed in the supine position, with less than 50 ml of urine in the bladder.
  • The UPR valuables measured were opening and closing pressure, opening and closing elastance and hysteresis.


  • The PVC tube was easy to insert to the same degree as a normal KAD.
  • Opening pressure and opening elastance were measured on all patients.
  • The sphincter area was easily identified during measurements.
  • UPR provides results compatible with previous techniques.
  • A standardized method for measurements was developed.


  • UPR has been shown feasible in the prostatic urethra.
  • Further studies on healthy volunteers and patients with lower urinary tract symptoms and benign prostatic obstruction (BPO) are needed, to determine if UPR has a future role in urodynamic diagnostics of male patients with BPO.