Abstract
The historical dogma that bladder calculi comprise the main indication for prostatic surgery has recently been questioned. In this study, we aimed to predict which patients should undergo simultaneous prostate and bladder calculi surgery or only bladder calculi removal by evaluating preoperative risk factors. One hundred and seventeen men with bladder stones and concomitant benign prostate enlargement (BPE) who had not received medical treatment before were included in the study. In the first step, only the bladder calculi of patients were removed and medical treatment was given for BPE. The patients who benefited from medical treatment during the follow-up were defined as Group 1 and the patients who required prostate surgery for any indication comprised Group 2. Risk factors for prostate surgery requirements were determined by comparing preoperative characteristics between the two groups with a cox regression model. In the follow-up of 117 patients with bladder stones removed and medical treatment initiated, 49 (41.9%) patients had prostate surgery indications. The indication for 33 (67.3%) of 49 patients was medical treatment failure. The presence of intravesical prostatic protrusion (IPP; hazard ratio: 2.071, 95% confidence interval [CI]: 1.05–4.05, P = 0.034), and high postvoiding residual urine volume (hazard ratio: 1.013, 95% CI: 1.007–1.019, P < 0.001) were found to be preoperative risk factors for needing future prostate surgery. In patients who have not received medical treatment for BPE before, bladder calculi developing secondary to BPE do not always constitute an indication for prostate surgery.
Keywords: benign prostate hyperplasia, bladder calculi, intravesical prostatic protrusion, medical therapy, prostate surgery
INTRODUCTION
Bladder calculi constitute only 5% of all urinary tract stones.1 This incidence is much higher in developing countries.2 Bladder calculi are classified as migrant, primary idiopathic, and secondary. Secondary stones usually occur as a result of benign prostate enlargement (BPE) in elderly men.3 Bladder calculi and concomitant BPE is a common clinical condition in urology practice and bladder calculi incidence is 3%−8% in patients with BPE.4,5
Advances in medical treatment have reduced the need for surgery due to BPE in recent years.6 However, surgical management of BPE is still an option for certain indications. Conventionally, the co-existence of bladder stone and BPE is the main indication for prostate surgery.7 Nowadays, prostate surgeries performed for BPE are usually transurethral resection of the prostate (TUR-P), open prostatectomy, or holmium laser enucleation of the prostate (HoLEP). Some patients may be unwilling to undergo prostate surgery due to adverse effects. The prolonged duration of anesthesia may also be risky for elderly men with comorbidities.
In this study, we aimed to demonstrate whether prostate surgery is absolutely indicated by determining preoperative risk factors in patients with bladder calculi and BPE.
PATIENTS AND METHODS
After obtaining ethical approval from the Ethics Review Board of Adana City Training and Research Hospital (Adana, Türkiye; Approval No. 72/1167), the prospectively maintained database records of 558 patients diagnosed with bladder calculi and concomitant BPE between January 2014 and January 2021 at Adana City Training and Research Hospital, and Adana Numune Training and Research Hospital (Adana, Türkiye), were retrospectively identified. Patients who underwent simultaneous prostate and bladder stone surgery (n = 398) were excluded from the study. Patients with neurogenic bladder (n = 6), history of bladder calculi removal or surgery for BPE (n = 4), history of renal or ureteral stone (n = 22), renal impairment (n = 2), urinary tract dilatation (n = 3), underactive detrusor (n = 3), or urethral stricture (n = 3) were excluded from the study. Patients who received previous medical therapy for BPE or did not receive medical therapy after calculi removal and who had recurrent urinary retention or indwelling Foley catheter were also excluded from the study. Figure 1 shows the flowchart for the study.
Figure 1.
Patient selection flow chart. BPE: benign prostate enlargement.
A total of 117 patients were included in the study. These patients chose bladder removal only, although combined surgery was recommended. Before bladder calculi removal, patient data such as age, Charlson Comorbidity Index (CCI) score, American Society of Anesthesiologists (ASA) score, International Prostate Symptom Score (IPSS), prostate-specific antigen (PSA), prostate volume, postvoiding residual (PVR) urine volume, uroflowmetry, and cystoscopy findings were recorded as baseline values. IPSS with the quality of life (QoL) index, ranging from zero (delighted) to six (terrible), was used as the QoL surrogate indicator. The stone size was calculated by ultrasonography using the maximum diameters of the largest calculi. Transabdominal ultrasonography (Prosound α6, Hitachi Aloka®, Twinsburg, OH, USA) was performed in all patients to measure the total prostate volume, intravesical prostatic protrusion (IPP), and PVR volume. The distance of intravesical prostatic protrusion was measured using the B mode between the two caliper marks from the base of the bladder to the maximum point of protrusion. Measurement of IPP was performed as described by Reis et al.8 The degree of IPP was classified as Grade 1 (≤5 mm), Grade 2 (>5 mm and ≤10 mm), and Grade 3 (>10 mm).9 Measurement of PVR was evaluated immediately after voiding (within 5 min) in the supine position. The greatest transverse (width), anteroposterior (depth) and superior–inferior (height) distances were recorded, and PVR was calculated automatically by ultrasonography. All patients were administered alpha-blockers and 5-alpha-reductase inhibitors after bladder calculi removal. Patients were reassessed at 1 month, 6 months, and 12 months and then annually after surgery by IPSS, uroflowmetry, and PVR urine volume. Deterioration in QoL index, presence of residual urine over 100 ml, an improvement lower than 30% for IPSS, and increase lower than 2 ml s−1 in maximum urinary flow rate (Qmax) value were considered a medical treatment failure.7,10 During follow-up, patients who benefited from the medical treatment after bladder calculi surgery were included in Group 1 (control group) and patients who underwent surgery for BPE due to medical treatment failure or any indication comprised Group 2. Preoperative baseline variables between the two groups and their effects on future prostate surgery were investigated. Patients who had undergone prostate surgery at the time of evaluation were excluded from further analysis. TUR-P or HoLEP was performed in all patients as the prostate surgical method. The presence of postoperative residual stones was evaluated according to abdominal ultrasonography as well as viewing with direct vision at the end of the surgical process. Residual stones with the size of 4 mm and below were considered stone free.
Statistical analyses
Descriptive statistics for data are given as mean ± standard deviation (s.d.), median, minimum–maximum, frequency, and percentage. Pearson’s Chi-square or Fisher’s exact test was used for categorical variables. Normality assumptions were checked with the Shapiro–Wilk test. The differences between the two groups were evaluated using the Student’s t-test for normally distributed data or Mann–Whitney U-test for nonnormally distributed data. Cox proportional hazards regression was used to identify independent preoperative factors that could predict the requirements for prostate surgery during follow-up. Statistical analysis was performed using IBM SPSS Statistics for Windows version 22.0 (IBM Corp., Armonk, NY, USA). P < 0.05 was considered statistically significant.
RESULTS
The age (mean ± s.d.) of 117 men included in the study was 63.9 ± 5.0 (range: 55.0–77.0) years. The IPSS (mean ± s.d.) of all patients before bladder stone removal was 22.5 ± 4.1. Patient preoperative characteristics and follow-up duration after bladder calculi removal are summarized in Table 1. Fifteen (12.8%) bladder stone surgeries were performed by percutaneous cystolithotripsy and 102 (87.2%) by transurethral cystolithotripsy approach. Stone-free status was achieved in all patients.
Table 1.
Comparison of preoperative baseline characteristics according to groups
| Characteristics | Group 1 (n=68) | Group 2 (n=49) | P |
|---|---|---|---|
| Age (year), median (IQR) | 63.5 (61.0–66.0) | 63.0 (59.0–68.7) | 0.606a |
| CCI score, median (IQR) | 4 (3–5) | 4 (4–6) | 0.141a |
| PSA (ng ml−1), median (IQR) | 1.8 (1.5–2.4) | 2.1 (1.7–2.5) | 0.176a |
| Preoperative IPSS, median (IQR) | 22.5 (18.0–25.0) | 24.0 (19.5–25.5) | 0.346a |
| Prostate volume (ml), median (IQR) | 52 (45–60) | 54 (44–64) | 0.780a |
| Qmax (ml s−1), median (IQR) | 12 (9–12) | 11 (8–11) | 0.035a |
| PVR volume (ml), median (IQR) | 92 (80–119) | 150 (122–167) | <0.001a |
| Diameter of largest stone (mm), median (IQR) | 22.5 (17.0–26.0) | 24.0 (21.0–30.0) | 0.004a |
| Number of stones, median (IQR) | 1 (1–2) | 2 (1–5) | 0.132a |
| Presence of IPP, n (%) | 9 (30.0) | 21 (70.0) | <0.001b |
| Grade 1 | 3 (50.0) | 3 (50.0) | |
| Grade 2 | 5 (41.6) | 7 (58.4) | |
| Grade 3 | 1 (8.3) | 11 (91.7) | |
| Time for prostate surgery (month), median (IQR) | 0 (0) | 20 (18–23) | |
| Duration of follow-up (month), median (IQR) | 41 (30–46) | 37 (36–38) | 0.501a |
aMann–Whitney U-test; bPearson’s Chi-square test. Group 1: patients who benefited from the medical treatment after bladder calculi removal; Group 2: patients who underwent surgery for BPE due to medical treatment failure or any indication. IQR: interquartile range; CCI: Charlson Comorbidity Index; PSA: prostate-specific antigen; IPSS: International Prostate Symptom Score; Qmax: maximum flow rate; PVR: postvoiding residual; IPP: intravesical prostatic protrusion
After bladder calculi removal, all patients received α1-blockers and/or 5 alpha-reductase inhibitors. The reduction in IPSS score (mean ± s.d.) after bladder calculi removal was 10.2 ± 3.9 (P < 0.001). Prostate surgery indications occurred in 49 (41.9%) patients at a median follow-up of 20 (range: 14–32) months. The indications for prostate surgery included medical treatment failure in 33 (67.3%) patients, urinary retention in 10 (20.4%), recurrent bladder calculi in 3 (6.1%), recurrent urinary tract infection in 2 (4.1%), and macroscopic hematuria 1 (2.1%) after bladder calculi removal. HoLEP was performed for 23 of the 49 patients (46.9%) and TUR-P was performed for the remaining 26 patients (53.1%).
Cox proportional hazards regression was performed to identify the factors that predicted the failure of bladder calculi removal plus medical therapy. The presence of IPP was the strongest factor to predict requirement for prostate surgery (hazard ratio: 2.071, 95% confidence interval [CI]: 1.05–4.05, P = 0.034). PVR urine volume was also found to be a statistically significant factor (hazard ratio: 1.013, 95% CI: 1.007–1.019, P < 0.001). Evaluation of preoperative risk factors to predict prostate surgery indication with the cox regression model is shown in Table 2.
Table 2.
Cox proportional hazards regression models for prediction of prostate surgery requirements
| Characteristics | P | HR | 95% CI | |
|---|---|---|---|---|
|
| ||||
| Lower | Upper | |||
| IPSS | 0.649 | 1.019 | 0.941 | 1.103 |
| Prostate volume (ml) | 0.323 | 1.013 | 0.987 | 1.039 |
| Stone diameter (mm) | 0.217 | 1.028 | 0.984 | 1.075 |
| Number of stones | 0.199 | 0.919 | 0.808 | 1.045 |
| Qmax (ml s−1) | 0.872 | 1.010 | 0.898 | 1.135 |
| PVR volume (ml) | <0.001 | 1.013 | 1.007 | 1.019 |
| IPP presence | 0.034 | 2.071 | 1.057 | 4.059 |
IPSS: International Prostate Symptom Score; Qmax: maximum flow rate; PVR: postvoiding residual; IPP: intravesical prostatic protrusion; CI: confidence interval; HR: hazard ratio
DISCUSSION
The approach has been accepted for years in cases of bladder calculi developing secondary to BPE is simultaneous surgical intervention for bladder calculi and prostate. In recent years, this indication has become questionable with the increasing success of medical treatment for patients with BPE.11 The main finding of our study is that prostate surgery is not an absolute requirement in every patient with concomitant bladder stones and BPE who have not received any medical treatment in the past.
The pathophysiology of bladder stone formation in the presence of BPE is still unclear. Studies in the literature reported that PVR urine and stasis play a major role in stone formation.12,13 The 3%–8% incidence of bladder stones in patients with BPE and stasis indicates that other factors also play a role in stone formation.4 Childs et al.14 defined these factors as a history of renal stones, gout, and various metabolic disorders. The normal range of PVR urine volume is considered to be 50–100 ml in elderly men.15 Philippou et al.11 found that high preoperative PVR urine volume was the only predictive risk factor for medical treatment failure in their prospective study. In our study, the need for prostate surgery was significantly higher during the follow-up of patients with high preoperative PVR urine volume, but the hazard ratio was only 1.01.
As a result of the success of medical treatments for patients with BPE, the need for surgery has decreased. In addition, the success of medical treatment allows patients to avoid complications caused by surgery. α1-blockers alone provide 30%–40% reduction in IPSS and 25% increase in Qmax.16 Furthermore, previous studies demonstrated that combination therapy is superior to monotherapy for IPSS and Qmax, and superior to α1-blockers alone in reducing the risk for needing surgical intervention.6,17 Hence, we preferred the combination therapy. Our series demonstrated similar results, with a 45% reduction in IPSS and 22% increase in Qmax after medical treatment. Surgical indications emerged in 49 out of 117 patients included during follow-up. In other words, 68 of the 117 patients were spared the possible complications of prostate surgery, whereas 33 (67.3%) of 49 patients had the prostate surgery indication of medical treatment failure.
The prostate anatomical structure is an important factor for predicting the success of medical treatment. It was shown that the benefit of medical therapy is limited in the presence of IPP.18 Recent studies demonstrated that IPP is an independent risk factor associated with the presence of bladder calculi in men with BPE.19,20 In the cox regression model, we constructed in our study, the presence of IPP was the most important factor for prostate surgery requirements during the follow-up. There was a 2.07-fold increased risk of prostate surgery in the presence of IPP.
Our study has some limitations. The main limitation of our study is the retrospective design. This may lead to the possibility of misclassification bias. Second, the follow-up period was not long enough. Last, the lack of confirmation of BPE with urodynamic findings is another limitation. On the other hand, our population number is higher than that in other studies in the literature.
CONCLUSION
This present study demonstrated that prostate surgery may not be an absolute indication in every patient with bladder stones and BPE. Bladder stone removal alone can be performed if IPP is not present and PVR volume is low in the preoperative features of patients who have not previously received medical treatment for BPE. Prospective randomized studies with long follow-up are needed about this subject in the future.
AUTHOR CONTRIBUTIONS
HA contributed to manuscript writing, data analysis, and project development. UÜ and HE contributed to project development and manuscript review. KK contributed to manuscript editing. FO performed literature search and data collection. All authors read and approved the final manuscript.
COMPETING INTERESTS
All authors declare no competing interests.
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