Usefulness of dynamic urethral resistance relation (DURR) measurement for differential diagnosis between static and dynamic urinary obstruction in male spinal cord injury patients

Objetive To study the validity of Dynamic Urethral Resistance Relation (DURR) for differential diagnosis between static and dynamic urinay obstruction in male spinal cord injury patients. Methods A case‐control study was conducted. The case group consisted of 24 male patients with spinal cord injury, aged under 40 years, with detrusor‐periurethral sphincter dyssynergia and bladder outlet obstruction (BOO) according to the urethral resistance factor (URA). The control group consisted of 24 male patients with no neurological lesions, aged over 49 years, diagnosis of benign prostatic hyperplasia (BPH) and BOO according to Schäfer's minimum urethral opening pressure (Pmuo) and the URA. A pressure/flow study was performed in both groups, and the DURR was recorded graphically. Results Both groups showed significantly different DURR characteristics with respect to the number of spikes (higher in the case group), the intensity of the first three spikes and the maximum duration of the spikes (significantly longer in the case group). The patients in the case group had a DURR characterized by at least three spikes, located throughout the whole voiding cycle (pattern A). The patients in the control group had a DURR mainly characterized by a spike located at the start of micturition and a maximum second spike located at the end of micturition (pattern B). Conclusions Pattern A showed a sensitivity with respect to the dynamic obstruction of 79% and a specificity of 100%. The sensitivity of pattern B with respect to the diagnosis of static obstruction was 71% and the specificity was 100%. Neurourol. Urodynam. 31:549–555, 2012. © 2012 Wiley Periodicals, Inc.