Korean J Urol.  2013 Jun;54(6):369-372.

Defining the Degree of Intravesical Prostatic Protrusion in Association With Bladder Outlet Obstruction

• Shin SH
• Kim JW
• Kim JW
• Oh MM
• Moon DG

Abstract

PURPOSE
The present study was done to define the degree of intravesical prostatic protrusion (IPP) causing bladder outlet obstruction (BOO) in patients with benign prostatic hyperplasia (BPH)/lower urinary tract symptoms.
MATERIALS AND METHODS
We retrospectively evaluated 239 patients with BPH, analyzing age, IPP, prostate volume, International Prostate Symptom Score (IPSS), and the results from a pressure-flow study. Urethral resistance was quantified by using the BOO index (BOOI), according to the formula BOOI=PdetQmax-2xQmax (where Pdet is detrusor pressure at the peak flow rate and Qmax is peak flow rate). BOO was defined by a BOOI above 40. Patients with a BOOI below 20 were excluded. Patients were classified into two groups (obstructed and unobstructed groups) by the BOOI. Correlations were determined by logistic regression analysis, and receiver operating characteristic curves were plotted to estimate the optimal cutoff for IPP.
RESULTS
There were significant differences in total prostate volume, postvoiding residual urine (PVR), IPP, and Qmax (p<0.001, p<0.001, p<0.001, and p=0.026, respectively) between the obstructed and unobstructed groups, but there were no significant differences in age (p=0.653), IPSS total score (p=0.624), or quality of life score (p=0.138). IPP had a significant prognosis (p<0.001) but was weakly correlated with prostate volume (p=0.026). The correlation coefficients between IPP and Qmax, PVR, prostate volume, and BOO were 0.551, -0.159, 0.225, and 0.391, respectively. For IPP, the area under the curve was 0.759 (95% confidence interval, 0.657 to 0.861) and the cutoff to indicate BOO was 5.5 mm with 66.7% sensitivity and 80.5% specificity.
CONCLUSIONS
An IPP exceeding 5.5 mm was significantly associated with BOO.

Keyword

Intravesical prostatic protrusion; Urinary bladder neck obstruction; ROC curve

MeSH Terms

Humans
Indoles
Logistic Models
Prognosis
Prostate
Prostatic Hyperplasia
Quality of Life
Retrospective Studies
ROC Curve
Urinary Bladder
Urinary Bladder Neck Obstruction
Urinary Tract
Indoles

Figure

• 

  FIG. 1 Schematic (ultrasound) image used in the grading system for intravesical prostatic protrusion (IPP). IPP is measured as the vertical distance from tip of the protrusion to the base of the bladder.

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  FIG. 2 Receiver Operating Characteristic curve for IPP and other parameters. IPP, intravesical prostatic protrusion; PSA, prostate-specific antigen; PV, prostate volume; PVR, postvoiding residual urine; Qmax, peak flow rate.

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