Introduction: Filling cystometry and pressure flow studies (PFS) are the most widespread used invasive urodynamic techniques in the assessment of male LUTS. However, these techniques are time- and cost-intensive. Intravesical prostatic protrusion (IPP) has been proposed as non-invasive method used to diagnose bladder outlet obstruction (BOO) in men with male lower urinary tract symptoms (LUTS). The purpose of the present review is to analyze the diagnostic and therapeutic relevance of IPP.
Evidence acquisition: A comprehensive systematic MEDLINE search was performed for English language reports published before June 2016 using the term "intravesical prostatic protrusion."
Evidence synthesis: We identified 28 eligible original articles. Determination of IPP seems as useful method to predict BOO. The area under the curve of IPP for the prediction of BOO was found to range from 0.708 (95% CI: 0.615-0.791) to 0.858 (95% CI: 0.809-0.908). IPP seems to have a predictive role in a successful trial without catheter following acute urinary retention. The percentage of successful TWOC in patients with IPP>10 mm was reported at 13% and 18%, respectively, compared to a approximately 80% chance of successful trial in patients with IPP<10 mm. The impact of IPP on postoperative outcomes following surgery for benign prostatic enlargement seems controversial. The heterogeneity of the current studies, the potential intra-observer variability and the potential learning curve need to be taken into account.
Conclusions: Analysis of IPP may be regarded as potential non-invasive alternative to standard PFS in the assessment of BOO. Patients with IPP>10 mm should be counseled regarding the high chance of need for surgical treatment following acute urinary retention.