Benign prostatic hyperplasia, or BPH, is the most common cause of bladder outflow obstruction in adult men, especially those older than 50 years. Choosing the right patients for the treatment, especially the surgical approaches, is an important issue. Many existing tests and indicators are used to evaluate the patients, including ultrasonographic evaluation, urodynamic tests, and serum biomarkers, which are most valuable in planning the treatment strategy. However, some of these tests have some limitations in clinical practice, especially they are invasive relatively and have potentially significant side effects. Thus, among all diagnostic methods, the non-invasive and readily available ultrasound evaluation has been suggested as an effective method. Since the introduction of the intravesical prostatic protrusion index (IPP) evaluated by ultrasonography, the relation between this index and the severity of bladder outflow obstruction has been shown. [1] However, until the early 21st century, the issue of the close relationship between the IPP and BPH had not yet been raised. It was hypothesized then that the IPP index, along with other objective and measurable indicators, may be useful for the evaluation and management of BPH. Besides, there was a close similarity between the results of the IPP measurement by the two means of transrectal and transabdominal ultrasonography and therefore, abdominal ultrasonography was suggested as a suitable tool for the determination of IPP. In this regard, ultrasonography will be able to accurately evaluate the structural abnormalities of the prostate, especially the bladder outflow obstruction, as a widely used and reliable non-invasive method. It seems that the measurement of the IPP index will not only have a high predictive ability to confirm the bladder outflow obstruction but also be able to predict the other clinical and structural abnormalities of the prostate. It seems that the use of IPP indices has high sensitivity and diagnostic accuracy in the clinical evaluation of the prostate even in comparison to the urodynamic indices. [2]
The present study aimed to investigate the clinical significance of the IPP index in BPH patients to clarify its diagnostic value in predicting the clinical and structural abnormalities of the prostate.

In this descriptive and analytical cross-sectional study, we include every man older than 50 years old with lower urinary tract symptoms (LUTS), predominantly voiding or obstructive, suggestive of BPH. Patients with a history of neurogenic bladder, diabetes mellitus, lumbar disc herniation, spinal trauma/surgery, urethral stricture/injury, or prostate cancer, and those with the absolute indications for surgery were excluded from the study. After standard clinical approach and making the diagnosis of BPH, the patients were evaluated to determine the following indices: IPSS (International Prostate Symptom Score) Index, QoL (quality of life) index obtained by a single question used to determine the “bother score” which provides a widely used and statistically valid measure, prostate volume (PV) and postvoid residual urine (PVR) assessed by transabdominal ultrasonography, serum PSA level, and the maximum urinary flow rate (Qmax) obtained by uroflowmetry. Subsequently, the assessment of the IPP index was undertaken by transabdominal ultrasonography. It should be noted that all the ultrasounds were performed by the same physician and the IPP was defined by the distance between the tip of the prostate's protrusion into the bladder and the bladder neck in sagittal view. (Fig-1)
The categorization of the IPP index was done into 3 grades: grade one (below 5 mm), grade two (between 5 and 10 mm), and grade three (greater than 10 mm). The results were expressed as mean and standard deviation (mean ± SD) for the quantitative variables and as percentages for the qualitative ones. SPSS software version 23 was used for statistical analysis and the quantitative variables were analyzed using a t-test or ANOVA test, while the chi-square test was used to compare the qualitative variables.

60 patients with the clinical diagnosis of BPH were enrolled in this study and were treated with tamsulosin 0.4 mg daily. The mean follow-up time was 3.97 ± 1.48 months (range 1.5 to 7 months). Of the 60 patients evaluated, 23 patients (38.3%) received finasteride 5 mg daily, concurrently. During the follow-up period, 10 patients (16.7%) underwent open prostatectomy or transurethral resection of the prostate (TURP).
The mean QoL (bother) scores before the treatment was 1.88 ± 0.88, 2.23 ± 1.09, and 2.95 ± 0.89 for the IPP grades 1,2, and 3, respectively, indicating a statistically significant difference between the three groups (P = 0.001). Meanwhile, the mean QoL scores after the medical intervention, were 1.76 ± 1.01, 2.08 ± 1.04, and 2.73 ± 1.35, respectively, for grades 1, 2, and 3 which again showed a significant difference (P = 0.020). According to Pearson correlation coefficient, there was a significant direct correlation between IPP and Qol (bother) scores either before (correlation coefficient = 0.459, P < 0.001) or after the intervention (cc = 0.353, P = 0.006). In general, with increasing the IPP score, the quality of life of the patients decreased significantly. (Table-1) 
The mean IPSS scores of patients, before the treatment, for grade 1, 2, and 3 subgroups were 10.88 ± 5.83, 12.62 ± 5.04%, and 16.36 ± 5.91, respectively. In other words, as the IPP increased, the patients' IPSS score also increased (P = 0.006). 
After the medical intervention, the mean IPSS scores were 11.08 ± 4.98, 11.54 ± 4.14, and 17.27 ± 8.21, respectively. (P = 0.003). According to Pearson correlation coefficient, there was a significant direct correlation between the IPP and IPSS scores either before (cc = 0.397, P = 0.002) or after the treatment (cc = 0.40, P = 0.001).
Finally, the prevalence of the need for the surgical intervention in the IPP grade 1, 2, and 3 subgroups were 4%, 7.7%, and 36.4%, respectively, which showed a significant difference between the subgroups so that the need for surgery increased with the IPP score increase (P <0.007).

The significant direct correlation between the intravesical prostatic protrusion and international prostate symptom score, quality of life, prostate volume, postvoid residual urine, and serum PSA as well as inversely with the maximum urinary flow rate was confirmed both before and after the medical treatment. Also, the need for surgical intervention increased significantly with increasing IPP levels.

The intravesical prostatic protrusion can be used to evaluate and predict the severity of symptoms and outcomes in patients with clinical BPH.

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Gandhi J, Weissbart SJ, Kim AN, Joshi G, Kaplan SA, Khan SA. Clinical Considerations for Intravesical Prostatic Protrusion in the Evaluation and Management of Bladder Outlet Obstruction Secondary to Benign Prostatic Hyperplasia. Curr Urol 2018; 12:6-12