Can noninvasive evaluation of benign prostatic obstruction be optimized?

[Correlation between detrusor thickness, intravesical prostatic protrusion and maximum urinary flow in the monitoring of benign prostatic hyperplasia]

INTRODUCTION

Detrusor thickness (DT) and intravesical prostatic protrusion (IPP) are closely related to bladder outlet obstruction. The aim of our study was to look for correlation between DT, IPP and maximum urinary flow (Qmax).

METHODS

It is a prospective, observational study including men over fifty managed for benign prostatic hyperplasia. Low urinary tract symptoms were assessed with the International Prostatic Symptom Score (IPSS). Pelvic ultrasound was performed for all patients measuring prostatic volume, bladder volume, post- void residual, DT and IPP. Uroflowmetry was performed for all patients, Qmax was noted. Qmax equal or less than 15ml/s was considered pathologic.

RESULTS

Sixty patients were included for our study. Strong negative correlation was noted between DT, IPP and Qmax (r=-0.59, r=-0.61 respectively). Patients with pathologic Qmax had higher DT and IPP than those with normal Qmax, the difference was significant (P<0.01). Threshold values predicting pathologic Qmax were 3mm for DT and 7mm for IPP. ROC analysis reveals for DT an AUC of 0.84 (95% CI 0.76-0.92) and for IPP an AUC of 0.88 (95% CI 0.80-0.97).

CONCLUSION

Detrusor thickness and intravesical prostatic protrusion have strong negative correlation with Qmax. These parameters could be an alternative to Qmax measurement if uroflowmetry is unavailable.

LEVEL OF EVIDENCE

Grade B.

Combination of intravesical prostatic protrusion and resistive index is useful to predict bladder outlet obstruction in patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia

OBJECTIVES

To examine which parameters obtained from transrectal ultrasonography are accurate predictors of urodynamically-confirmed bladder outlet obstruction in patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia.

METHODS

The records of 350 patients with complaints of lower urinary tract symptoms suggestive of benign prostatic hyperplasia were reviewed. Baseline parameters were international prostate symptom score, quality of life score, postvoid residual urine volume, prostate-specific antigen, and data obtained from uroflowmetry and transrectal ultrasonography. Urodynamic studies were carried out to determine bladder outlet obstruction. Receiver operator characteristic curves were generated to compare the accuracy of the different parameters, and the area under the curve of each parameter was calculated.

RESULTS

Bladder outlet obstruction index positively correlated with intravesical prostatic protrusion, total prostate volume, transition zone volume, transition zone index, resistive index and prostate-specific antigen. Further, resistive index was only a significant independent variable with intravesical prostatic protrusion. Intravesical prostatic protrusion had the highest area under the curve of 0.790 among all variables, and its cut-off value was 10 mm. The positive predictive value of intravesical prostatic protrusion was 76.2%. In addition, the positive predictive value of the combined parameters intravesical prostatic protrusion and resistive index increased to 83.8%.

CONCLUSIONS

Intravesical prostatic protrusion and resistive index are useful parameters for predicting bladder outlet obstruction in patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia. In clinical practice, the combination of intravesical prostatic protrusion and resistive index on ultrasound can be diagnostic of bladder outlet obstruction.

Prostatic elasticity: a new non-invasive parameter to assess bladder outlet obstruction caused by benign prostatic hyperplasia (a canine experiment)

OBJECTIVE

To evaluate the change of prostatic elasticity during the development of benign prostatic hyperplasia (BPH) and its correlation with the degree of bladder outlet obstruction (BOO) in the canine model of BOO caused by BPH.

MATERIALS AND METHODS

Ten male beagle dogs were selected in this study. To establish canine model of BOO caused by BPH, each beagle underwent castration surgery followed by encapsulating the prostate with a double layer of nylon mesh and then treating the beagles with a combination of steroids for 12 weeks. Transrectal ultrasound (TRUS) examination and urodynamic evaluation were performed before and at 4, 8, and 12 weeks of hormone administration. Prostatic volume, Young modulus of prostatic tissue, and urodynamic parameters were compared at each time instance, and the correlation between the Young modulus of the prostatic tissue and urodynamic parameters were evaluated.

RESULTS

All beagles developed BOO caused by BPH over the time period of the study. Prostatic volume, Young modulus of prostatic tissue, and urodynamic parameters had statistically significant differences before and after 4, 8, and 12 weeks of hormone administration (P <.05). Young modulus of prostatic tissue showed a very significant correlation with urodynamic parameters, including maximum urine flow (Qmax) (r = -0.802, P <.01), Qave (r = -0.711, P <.01), Pves@open (r = 0.638, P <.01), Pves@Qmax (r = 0.699, P <.01), Pdet@Qmax (r = 0.757, P <.01), and Pdetmax (r = 0.739, P <.01).

CONCLUSION

Young modulus of prostatic tissue increased during the development of the BPH. There was a significant correlation between Young modulus of prostatic tissue and the degree of BOO.

Monitoring Detrusor Oxygenation and Hemodynamics Noninvasively during Dysfunctional Voiding

The current literature indicates that lower urinary tract symptoms (LUTSs) related to benign prostatic hyperplasia (BPH) have a heterogeneous pathophysiology. Pressure flow studies (UDSs) remain the gold standard evaluation methodology for such patients. However, as the function of the detrusor muscle depends on its vasculature and perfusion, the underlying causes of LUTS likely include abnormalities of detrusor oxygenation and hemodynamics, and available treatment options include agents thought to act on the detrusor smooth muscle and/or vasculature. Hence, near infrared spectroscopy (NIRS), an established optical methodology for monitoring changes in tissue oxygenation and hemodynamics, has relevance as a means of expanding knowledge related to the pathophysiology of BPH and potential treatment options. This methodological report describes how to conduct simultaneous NIRS monitoring of detrusor oxygenation and hemodynamics during UDS, outlines the clinical implications and practical applications of NIRS, explains the principles of physiologic interpretation of NIRS voiding data, and proposes an exploratory hypothesis that the pathophysiological causes underlying LUTS include detrusor dysfunction due to an abnormal hemodynamic response or the onset of oxygen debt during voiding.