Incorporation of bipolar technology in transurethral resection (TUR) of the prostate (TURP) potentially offers advantages over monopolar TURP (M-TURP).
To evaluate the evidence by a meta-analysis, based on randomized controlled trials (RCTs) comparing bipolar TURP (B-TURP) with M-TURP for benign prostatic obstruction. Primary end points included efficacy (maximum flow rate [Qmax], International Prostate Symptom Score) and safety (adverse events). Secondary end points included operation time and duration of irrigation, catheterization, and hospitalization.
Based on a detailed, unrestricted strategy, the literature was searched up to February 19, 2009, using Medline, Embase, Science Citation Index, and the Cochrane Library to detect all relevant RCTs. Methodological quality assessment of the trials was based on the Dutch Cochrane Collaboration checklist. Meta-analysis was performed using Review Manager 5.0.
Sixteen RCTs (1406 patients) were included. Overall trial quality was low (eg, allocation concealment and blinding of outcome assessors were poorly reported). No clinically relevant differences in short-term (12-mo) efficacy were detected (Qmax: weighted mean difference [WMD]: 0.72 ml/s; 95% confidence interval [CI], 0.08–1.35; p = 0.03). Data on follow-up of >12 mo are scarce for B-TURP, precluding long-term efficacy evaluation. Treating 50 patients (95% CI, 33–111) and 20 patients (95% CI, 10–100) with B-TURP results in one fewer case of TUR syndrome (risk difference [RD]: 2.0%; 95% CI, 0.9–3.0%; p = 0.01) and one fewer case of clot retention (RD: 5.0%; 95% CI, 1.0–10%; p = 0.03), respectively. Operation times, transfusion rates, retention rates after catheter removal, and urethral complications did not differ significantly. Irrigation and catheterization duration was significantly longer with M-TURP (WMD: 8.75 h; 95% CI, 6.8–10.7 and WMD: 21.77 h; 95% CI, 19.22–24.32; p < 0.00001, respectively). Inferences for hospitalization duration could not be made. PlasmaKinetic TURP showed an improved safety profile. Data on TUR in saline (TURis) are not yet mature to permit safe conclusions.
No clinically relevant differences in short-term efficacy exist between the two techniques, but B-TURP is preferable due to a more favorable safety profile (lower TUR syndrome and clot retention rates) and shorter irrigation and catheterization duration. Well-designed multicentric/international RCTs with long-term follow-up and cost analysis are still needed.
Keywords: Benign prostatic hyperplasia, Bipolar, Electrosurgery, Meta-analysis, PlasmaKinetic, Prostate, Randomized controlled trial, Review, Saline, Transurethral resection of prostate.
Benign prostatic hyperplasia (BPH) is the only tumor that inevitably affects almost every aging male, and there is consensus on its progressive nature . BPH-related obstruction (ie, benign prostatic obstruction [BPO])  is associated with lower urinary tract symptoms (LUTS). The incidence of LUTS/BPO is high and increases linearly with age . The impact on quality of life (QoL) and health care cost justifies additional research into the use of therapeutic resources .
For 8 decades, transurethral resection of the prostate (TURP) has been considered the cornerstone of surgical management for BPO, due to the procedure's outstanding, well-documented, long-term treatment efficacy . Similar data on durability for any other instrumental BPO treatment are lacking , and the evidence supports the notion that “TURP is here to stay” .
Although significant technical improvements during the past 15 yr have reduced intra- and postoperative adverse events, there are still concerns regarding complications, such as transurethral resection (TUR) syndrome, bleeding, and urethral strictures (USs) . A prospective multicenter study on 10 654 patients with BPO treated with TURP showed that mortality has decreased (0.1%) but that morbidity, although reduced, continues to be high (11.1%) . The most significant recent technical modification of TURP is the incorporation of bipolar technology. Bipolar TURP (B-TURP) addresses a fundamental flaw of monopolar TURP (M-TURP) by allowing performance in normal saline, and the technique seems to be promising .
The purpose of this systematic review is to critically evaluate the evidence based on randomized controlled trials (RCTs) that compare B-TURP with M-TURP in patients with BPO and, where possible, to conduct a quantitative meta-analysis in an attempt to provide, for the first time, conclusions based on level 1a evidence. We aim to substantiate the advantages and disadvantages of each technique in terms of efficacy and safety (primary outcomes). Efficacy was quantified by postoperative maximum flow rate (Qmax) and/or International Prostate Symptom Score (IPSS). Reoperation for residual tissue was also considered. Safety was estimated by the postoperative occurrence of at least one of the following parameters: (1) drop in serum sodium level, (2) TUR syndrome, (3) drop in hemoglobin (Hb) level, (4) need for transfusion, (5) clot retention, (6) acute urinary retention (AUR) after catheter removal, (7) meatal stenosis (MS), (8) bladder neck contracture (BNC), and (9) US. Secondary outcomes included operation time, duration of bladder irrigation, catheterization, and hospitalization time.
2. Evidence acquisition
Objectives, literature-search strategy, methods for determining trial selection based on strict inclusion criteria, data elements, data extraction, and trial quality assessment were defined beforehand. Each step in this protocol was completed independently by two of the authors (CM and DU). Any disagreement was resolved by discussion, and final decision was based on a consensus.
2.1. Literature-search strategy
The literature was systematically searched with the assistance of a clinical librarian to detect all RCTs comparing B-TURP with M-TURP in patients with BPO. The search was conducted up to February 19, 2009, using the following electronic databases: Medline, Embase, Science Citation Index, and the Cochrane Library up to issue 1 of 2009. No temporal, regional, publication status, or language restrictions were set. The search strategy is summarized in Appendix A. The official Web sites of the manufacturers of all currently commercially available B-TURP systems were also checked. The reference lists of all selected papers were further reviewed for potentially relevant trials.
Eligible trials were full papers reporting on at least one of the two primary outcomes of interest: efficacy and safety. If necessary, official translations into English or Dutch were obtained through the independent Dutch Interpretation and Translation Center (www.tvcn.nl). Citations in abstract form, trials that studied different interventions (eg, transurethral vaporization of the prostate [TUVP] or transurethral vaporization-resection of the prostate [TUVRP], laser technology), and non-RCTs were excluded.
2.2. Quality assessment, data extraction and analysis
The methodological quality assessment of selected trials was based on the Dutch Cochrane Collaboration checklist, which is in accordance with Table 8.5.a of the Cochrane Handbook for Systematic Reviews of Interventions.
Data of the included trials were extracted and summarized. Unreported complications were considered to be not recorded unless specifically stated as not occurring. Meta-analysis was performed using Review Manager 5.0 (Cochrane Collaboration, Oxford, UK).
Statistical heterogeneity was assessed using the I2 statistic. In the absence of heterogeneity (I2: <30%), a fixed effects model was used. A random effects model was used for mild heterogeneity (I2: 30–60%). For I2 >60% we refrained from doing a meta-analysis. If data could be pooled, depending on heterogeneity , summary estimates of treatment effect with 95% confidence intervals (CIs) were calculated for every comparison and the p-value for the overall treatment effect was added. For continuous variables, the weighted mean difference (WMD) was calculated. For dichotomous outcomes, the absolute risk reduction or risk difference (RD) was used, which is an absolute effect measure of the difference between experimental and control event rates, allowing calculation of the numbers needed to harm (NNH). The presence of publication bias, if any, was evaluated using funnel plots. In the case of clinical or statistical heterogeneity, sensitivity analyses were attempted to facilitate the meta-analysis by omitting trials with an apparent reason for heterogeneity. Subgroup analysis of the different bipolar systems was planned beforehand.
3. Evidence synthesis
3.1. Previously published systematic reviews and meta-analyses
Although many interesting reviews have recently been published , , , , , and , only two reports by the same group of investigators fulfilled the methodological standards of a systematic review  and . The first one compared the efficacy and safety of newer ablative methods (including B-TURP) against M-TURP for treating patients with BPO . The second extended the attempt toward a cost-effectiveness comparison (B-TURP was not evaluated in this respect), including nonablative, minimally invasive techniques . Based on a systematic literature search through September 2006, both reports considered the same RCTs, only six in total (386 patients) , , , , , and .
IPSS was the primary outcome; others included Qmax, duration of operation, length of hospital stay, reoperation, and adverse events  and . The authors concluded that data were too few to provide precise estimates and that statistically significant differences could not be detected. Duration of the operation was the only exception, favoring B-TURP, which bore a significant heterogeneity and was of doubtful clinical or economic importance .
3.2. Trial inclusion
A total of 573 citations were retrieved from databases and a manufacturer's Web site (Fig. 1). Finally, 17 reports on 16 RCTs matched the inclusion criteria , , , , , , , , , , , , , , , , and .
Flow-chart of selecting randomized controlled trials for analysis. B-TURP = bipolar transurethral resection of the prostate; B-TUVP = bipolar transurethral vaporization of the prostate; M-TURP = monopolar transurethral resection of the prostate; RCT = randomized controlled trial.
Eligibility was not obvious from the titles and abstracts alone in four cases , , , and , and the final decision was based on a review of the full manuscript after requesting official translation in two cases, one from Korean  and one from Chinese . In this way, three studies were excluded (no evidence of randomization  and  or retrospective study design ). Furthermore, one trial was excluded because the intervention arm received a combination of B-TUVP and B-TURP (hybrid technique) instead of B-TURP alone .
Two of the 17 trials described the same set of patients and reported identical information at 12-mo follow-up  and . Only extra data on longer-term (48 mo) follow-up were extracted from the most recent publication . Among the remaining trials, there was no evidence of duplicate populations. In two trials from the same group of investigators, it was obvious that results were reported on different patients because the trial periods did not overlap  and .
Compared to the previously published systematic reviews  and , we report on a much greater trial and patient population. The previous authors provided no evidence other than the period of the literature search to justify the exclusion of any trial that was included in the present review, and they analyzed only 31% of the trials we included (5 of 16) , , , , and  as well as the sole RCT that we excluded .
3.3. Description of included trials
Trial sizes ranged from 40 to 240 patients, totaling 1406 patients randomized into B-TURP and M-TURP arms. There was no evidence of significant clinical heterogeneity regarding patient inclusion criteria, preoperative patient characteristics, and performance of treatments. Only one trial included patients with markedly larger prostates compared to the others . The main trial and baseline patient characteristics are summarized in Table 1.
Trial and preoperative patient characteristics
|Reference||Country of origin||Trial size‡||Resectoscope, F‡||Bipolar technology||Follow-up, mo||Age, yr‡||Prostate volume, ml‡||Hemoglobin, g/dl‡||Sodium, mmol/l‡||Qmax, ml/s‡||IPSS‡||QoL score‡||PVR, ml‡|
|Yang et al, 2004 ||Taiwan||59/58||na/na||PK||3||na/na||48.9/45.8||13.7/13.5||138.8/140.8||10.9/10.4||21.6/20.9||4.0/3.7||150/99|
|Singh et al, 2005 ||India||30/30||25.5/25.6||Vista CTR||3||67.9/68.9||na||13.2/12.8||139.2/139.3||5.1/5.8||21.6/20.5||4.4/4.6||136/124|
|De Sio et al, 2006 ||Italy||35/35||26/26||PK||12||61.0/59.0||47.5/51.6||na||na||6.3/7.1||24.3/24.2||3.9/4.2||75/80|
|Autorino et al, 2009 ||48|
|Nuhoglu et al, 2006 ||Turkey||30/27||25/27||PK||12||65.2/64.6||49.0/47.0||14.6/14.1||141.1/141.4||7.3/6.9||17.3/17.6||na||88/96|
|Seckiner et al, 2006 ||Turkey||24/24||26/27||PK||12||63.9/61.2||41.4/49.4||14.3/14.1||147.1/148.0||8.3/8.5||23.2/24.1||4.7/4.4||138/88|
|Patankar et al, 2006 ||India||51/53||24/na||PK||0.7||62.0/64.0||52.3/51.3||na||na||6.4/5.9||23.7/23.3||na||na|
|Kim et al, 2006 ||Korea||25/25||24/27||PK||6||70.6/68.1||51.7/53.2||na||na||na||na||na||na|
|Abascal Junquera et al, 2006 ||Spain||21/24||26/26||TURis||na||67.3/69.5||42.5/39.5||na||na||7.2/7.7||na||na||na|
|Ackayoz et al, 2006 ||Turkey||21/21||26/27||PK||na||66.0/67.0||47.0/40.0||na||141.0/140.0||na||na||na||na|
|Lin et al, 2006 ||Taiwan||18/22||26/26||Vista CTR||12||69./69.0||na||na||na||6.0/7.0||29.5/29.5||na||na|
|Erturhan et al, 2007 ||Turkey||120/120||26/27||PK||12||67.4/68.5||42.0/43.0||na||na||9.2/10.9*||24.0/23.0||3.0/2.0||135/114*|
|Ho et al, 2007 ||Singapore||52/48||26/26||TURis||12||66.5/66.6||54.8/56.5||14.8/14.0*||141.0/139.5||6.5/6.8||24.6/22.6||na||na|
|Rose et al, 2007 ||Germany||34/38||na/na||TURis||na||na/na||na||na||na||na||na||na||na|
|Michielsen et al, 2007 ||Belgium||120/118||26/24||TURis||na||73.1/73.8||na||14.1/13.4||142.0/142.2||na||na||na||na|
|Iori et al, 2008 ||Italy||27/26||26/24||PK||12||63.0/65.0||48.0/49.0||na||141/140||8.7/7.0*||20.0/21.0||3.6/3.0||96/99|
|Bhansali et al, 2009 ||India||35/35||26/26||PK||12||na/na||82.6/82.4||na||na||4.2/4.4||na||na||na|
F = French; IPSS = International Prostate Symptom Score; na = not available; PK = PlasmaKinetic technology; PVR = postvoid residual urine volume; Qmax = maximum flow rate; QoL = quality of life; TURis = transurethral resection in saline; Vista CTR = Vista Coblation/controlled tissue resection.
‡ The data for the monopolar/bipolar techniques are given, respectively.
* Significant difference between monopolar and bipolar transurethral resection arms.
3.4. Methodological quality
Overall trial quality was low. True (computer-aided) randomization was used in only two trials  and . Half did not report the randomization method , , , , , and . Consequently, allocation concealment could not be guaranteed in at least 50% of the trials. Withdrawals, if any, were rarely mentioned. Blinding of patients and outcome assessors for the treatment received were stated clearly in only two trials  and  and five trials , , , , and , respectively, while the nature of the intervention made blinding of the performing physicians impossible. In two trials, it was clearly stated that at least some patients were treated differently apart from the intervention  and . Specifically, three patients in the M-TURP arm received furosemide because serum sodium levels approached the lower normal limits versus none in the B-TURP arm , while patients in the M-TURP arm but not in the B-TURP arm were routinely treated with furosemide if resection time was >60 min . Acquisition of informed consent , , , , , , , and  and local ethics committee approval , , , and  were hardly reported. A sample size calculation was performed in only two trials  and , so most trials were likely to be underpowered. Financial support by a manufacturer was mentioned in only one trial , while the rest provided no information. Consequently, a potential reporting bias introduced by such support could not be ruled out. The methodological quality of the trials is summarized in Table 2.
Quality assessment of the included randomized controlled trials
|Yang et al, 2004 ||Yes||?||Yes||No||Yes||No||?||No||?||?||?||Yes||?||?||?||No|
|Singh et al, 2005 ||Yes||Yes||Yes||No||Yes||No||?||No||Yes||?||Yes||Yes||?||?||?||No|
|De Sio et al, 2006 ||Yes||Yes||Yes||Yes||Yes||No||?||No||Yes||Yes||No||Yes||Yes||Yes||No||Yes|
|Autorino et al, 2009 |
|Nuhoglu et al, 2006 ||Yes||?||Yes||Yes||Yes||No||?||No||?||Yes||Yes||Yes||Yes||Yes||?||No|
|Seckiner et al, 2006 ||Yes||?||Yes||No||Yes||No||?||No||?||Yes||Yes||Yes||?||?||?||No|
|Patankar et al, 2006 ||Yes||Yes||Yes||Yes||Yes||No||Yes||No||Yes||Yes||Yes||Yes||Yes||?||?||No|
|Kim et al, 2006 ||Yes||?||Yes||No||Yes||No||?||No||?||?||Yes||Yes||?||?||?||No|
|Abascal Junquera et al, 2006 ||Yes||?||Yes||No||Yes||No||?||No||Yes||Yes||Yes||Yes||?||?||?||No|
|Ackayoz et al, 2006 ||Yes||?||Yes||No||Yes||No||?||No||?||Yes||Yes||Yes||?||?||?||No|
|Lin et al, 2006 ||Yes||Yes||Yes||Yes||Yes||No||?||No||?||Yes||No||Yes||Yes||?||?||No|
|Erturhan et al, 2007 ||Yes||?||Yes||Yes||Yes||No||?||No||?||Yes||Yes||Yes||?||?||?||No|
|Ho et al, 2007 ||Yes||Yes||Yes||Yes||Yes||No||?||No||?||Yes||Yes||Yes||Yes||Yes||?||No|
|Rose et al, 2007 ||Yes||?||?||No||Yes||No||?||No||?||Yes||Yes||Yes||Yes||?||?||No|
|Michielsen et al, 2007 ||Yes||Yes||Yes||No||Yes||No||?||No||?||?||Yes||Yes||Yes||Yes||?||No|
|Iori et al, 2008 ||Yes||Yes||Yes||No||Yes||No||?||No||?||?||Yes||Yes||?||?||?||No|
|Bhansali et al, 2009 ||Yes||Yes||Yes||No||Yes||No||Yes||No||Yes||Yes||Yes||Yes||Yes||?||?||Yes|
1 = randomization; 2 = allocation concealment; 3 = baseline comparability of groups; 4 = withdrawals described; 5 = intention to treat; 6 = differencial loss to follow-up; 7 = patients blinded; 8 = treating physician blinded; 9 = outcome assesors blinded; 10 = proportion of patients that completed follow-up >80%; 11 = similar treatment appart from intervention; 12 = reliability of outcome measures; 13 = informed consent; 14 = approved by medical ethics committee; 15 = financial support; 16 = sample size calculation; ? = unknown.
3.5. Primary end points
Data on efficacy measured by the impact of each technique on Qmax and IPSS , , , , , , , , , , , and  as well as QoL score , , , , , , and , compared to baseline, was provided at follow-up periods ranging from 1 to 48 mo in 12 trials. All trials but one  concluded that both techniques were equally effective. Pooling five trials reporting on Qmax at 12 mo (Fig. 2) showed a small but significant (p = 0.03) difference favoring B-TURP (WMD: 0.72 ml/s; 95% CI, 0.08–1.35). This difference, however, is hardly clinically relevant and is largely influenced by Erturhan et al's trial . They were the only authors to report a statistically significant difference (1 ml/s) favoring B-TURP, which may be attributed to a statistically significant difference (but of questionable clinical significance) detected between arms at baseline (Table 1). In contrast, based on four and three trials that could be pooled regarding IPSS , , , and  and QoL score , , and , respectively, no differences were detected at 12 mo (IPSS: WMD: 0.05; 95% CI, −0.40 to 0.51; p = 0.82; QoL score: WMD: 0.04; 95% CI, −0.17 to 0.24; p = 0.72). Longer-term data were provided in a small trial with the longest follow-up (48 mo) to date . Both techniques was reported to be equally effective, and the significant improvements compared to baseline were maintained at 48 mo. Due to lack of standard deviations, data could not be interpreted. Reoperation for residual adenoma was reported in one patient per arm, while no such event was reported in other trials  and . In conclusion, presently available evidence showed no clinically relevant differences in short-term efficacy between B-TURP and M-TURP. Data on long-term follow-up of B-TURP appear to be scarce in contrast to M-TURP .
Forest plot of maximum flow rate (Qmax; ml/s) at 12 mo postoperatively. CI = confidence interval; IV = inverse variance; SD = standard deviation.
Although a significant decrease in TUR syndrome incidence has been reported during the past decades, it still represents a serious perioperative complication . Function in a conductive medium instead of the conventional nonconductive irrigation fluid is a prerequisite of bipolar technology. This advantage is the most important because all issues relating to hypotonic/hypo-osmolar fluid irrigation (dilutional hyponatremia, TUR syndrome) are expected to be eliminated . Therefore, bipolar technology is expected to provide more time to perform larger resection, coagulation, and training without compromising safety  and .
Most trials reporting on the postoperative drop in serum sodium level showed a significantly higher drop after M-TURP , , , , , , and , but data were extremely heterogeneous to be pooled (I2: 99%). Because the absolute serum sodium levels at baseline did not differ significantly between arms (Table 1), postoperative levels (at 2 h) were evaluated instead. Four trials could be pooled , , , and , showing a small but significantly lower sodium level after M-TURP (WMD: 1.36 mmol/l; 95% CI, 0.81–1.90; p < 0.00001).
All trials but one  reported on TUR syndrome occurrence, describing a total of 13 cases versus none after M-TURP and B-TURP, respectively. No significant difference was reported in individual trials. Pooled analysis (Fig. 3) detected an overall significant difference (RD: 2%; 95% CI, 0–3%; p = 0.01). This means an NNH of 50 (95% CI, 33–111), meaning that treating 50 patients with B-TURP will result in one fewer case of TUR syndrome than when treating with M-TURP. Considering a reported incidence of up to 2.1% , our results provide strong evidence to support the notion that “with B-TURP, dilutional hyponatremia of TUR-syndrome is a historical event in the 21st century” . Bipolar technology, however, does not prevent fluid absorption, which can still happen; therefore, it should always be kept in mind . In a retrospective study , even unexpected hyponatremia and pulmonary edema was reported in one case and was attributed to secondary fluid shifts between intra- and extravascular compartments unrelated to the saline irrigation.
Forest plot of transurethral resection syndrome occurrence. CI = confidence interval; M-H = Mantel Haenszel.
One of the major complications of M-TURP is intra- or perioperative bleeding, which is clinically significant mainly if it causes clot retention or necessitates blood transfusion or reoperation. Although transfusion rates in M-TURP series have been significantly reduced over time, clot retention incidence ranges between 2% and 5% and bleeding still remains a concern . The hemostatic capacity of bipolar current has been reported to be superior in a number of ex vivo studies, possibly attributed to deeper coagulation depths , , , , , and , as well as to the “cut-and-seal” effect of plasma created by bipolar energy  and .
Data on the postoperative change in Hb level were available from nine trials , , , , , , , , and , all reporting a nonsignificant drop between arms. Due to lack of standard deviations and large heterogeneity , , , and , they could not be pooled. Although all individual trials but one  reported a nonsignificant difference in clot retention between arms, pooled analysis (Fig. 4) showed a significantly higher frequency in the M-TURP arm (RD: 5%; 95% CI, 1–10%; p = 0.03). This means an NNH of 20 (95% CI, 10–100), meaning that treating 20 patients with B-TURP will result in one fewer case of clot retention than when treating with M-TURP. This seems to be clinically significant, considering the incidence of clot retention . Twelve trials reported on the need for blood transfusions. All individual trials reported a nonsignificant difference in blood transfusion rates between arms. Pooled analysis (Fig. 5) verified this result. Fewer cases required transfusion in the B-TURP arm, but the difference was not significant (RD: 2%; 95% CI, 0–4%; p = 0.10).
Forest plot of clot retention occurrence. CI = confidence interval; M-H = Mantel Haenszel.
Forest plot of cases requiring blood transfusion. CI = confidence interval; M-H = Mantel Haenszel.
Pooling of the eight trials , , , , , , , and  reporting on AUR showed no differences between arms (RD: 1%; 95% CI, −2% to 3%; p = 0.59), confirming all individual trial results.
The major late complications of M-TURP include strictures (US and MS: 2.2–9.8%) and BNCs (0.3–9.2%), and the incidence has not changed significantly over time, despite improvements in surgical techniques, lubricants, instruments, and electrical technology . Theoretically, bipolar technology minimizes the risk of USs, but the different electrode arrangements of the various systems should be considered separately .
Higher incidences of urethral complications (immediate urethral injury during entrance, MS , USs  and ) with bipolar systems have been suggested occasionally. Larger resectoscope diameter (27F) (PlasmaKinetic [PK]; Gyrus ACMI, Southborough, MA, USA) , , , and , higher ablative energy used , and longer procedures  have been proposed as risk factors. USs specifically associated with the TUR in saline (TURis) system (Olympus, Tokyo, Japan) have been attributed to electric current return (leakage) via the resectoscope sheath , but this concern has not been verified .
Alarming results were provided by Tefekli et al , raising serious concerns about bipolar technology in the urological community . The authors reported significantly more and severe USs in the PK arm (PK vs M-TURP: 3 of 49 vs 1 of 47; Fisher exact test, p = 0.002) after quite a long follow-up (18.3 ± 6.7 mo) of 96 patients. Although we excluded this trial from our meta-analysis, we previously reported this difference to be insignificant (p = 0.617) . This also holds true for any individual RCT (Table 3). Pooled analysis (Fig. 6) verified that differences in cumulative incidence rates at 12 mo were insignificant. Accrual of increased numbers of patients and/or longer follow-up, however, may change these results.
Complications from urethra and bladder neck in patients treated with monopolar versus bipolar transurethral resection of the prostate (TURP): Data reported in randomized controlled trials (RCTs)
|Reference||Mean follow-up, mo||Monopolar TURP||Bipolar TURP||p value|
|N||Strictures, n (%)a||Stricture location||Detection, mo||Intervention||N||Device||Strictures, n (%)a||Stricture location||Detection, mo||Intervention|
|Singh et al, 2005 ||3||30||0 (0.0)||U||–||–||30||Vista CTR||1 (3.3)||U||na||na||1.000|
|1 (3.3)||BN||na||na||0 (0.0)||–||–||–||1.000|
|Lin et al, 2006 ||12||18||1 (5.6)||BN||9||Incision||22||Vista CTR||0 (0.0)||–||–||–||0.450|
|Total US (Vista CTR)||48||0 (0.0)||52||1 (1.9)||1.000|
|Yang et al, 2004 ||3||59||2 (3.4)||U||na||Urethrotomy||58||Gyrus||1 (1.7)||U||na||Urethrotomy||1.000|
|De Sio et al, 2006 ||12||35||1 (2.9)||BN||6||Reoperation||35||Gyrus||1 (2.9)||BN||6||Reoperation||1.000|
|Autorino et al, 2009 ||48||31||2 (6.5)||BU||na||Urethrotomy||32||Gyrus||1 (3.1)||BU||na||Urethrotomy||0.613|
|1 (3.2)||BN||6||Incision||1 (3.2)||BN||6||Incision||1.000|
|Nuhoglu et al, 2006 ||12||26||0 (0.0)||–||–||–||24||Gyrus||1 (4.2)||UM||3||Dilatation||0.480|
|Seckiner et al, 2006 ||12||24||1 (4.2)||BU||–||Urethrotomy||24||Gyrus||1 (4.2)||BU||–||Urethrotomy||1.000|
|0 (0.0)||–||–||–||1 (4.2)||MU||–||1.000|
|Kim et al, 2006 ||6||25||2 (8.0)||U||na||na||25||Gyrus||1 (4.0)||U||na||na||1.000|
|Erturhan et al, 2007 ||12||120||0 (0.0)||–||–||–||120||Gyrus||3 (2.5)||UIb||At entrance||–c||0.247|
|2 (1.7)||UM||na||na||3 (2.5)||UM||na||na||1.000|
|2 (1.7)||U||na||Reoperationd||2 (1.7)||U||na||na||1.000|
|1 (0.8)||BN||na||Reoperation||0 (0.0)||BN||–||–||1.000|
|Iori et al, 2008 ||12||26||1 (3.8)||BN||4||Urethrotomy||27||Gyrus||1 (3.7)||BN||4||Urethrotomy||1.000|
|Bhansali et al, 2009 ||9e||33||4 (12.1)||U||na||Urethrotomy||34||Gyrus||5 (14.7)||U||na||Urethrotomy||1.000|
|0 (0.0)||BN||na||–||1 (2.9)||BN||na||Incision||1.000|
|Total US (Gyrus)f||344||11 (0.3)||344||11 (0.3)||1.000|
|Ho et al, 2007 ||12||52||1 (1.9)||BU||2||Dilatation||48||TURis||3 (6.3)||BU||2||Dilatation||0.348|
|Michielsen et al, 2007 ||na||120||0 (0.0)||–||–||–||118||TURis||0 (0.0)||–||–||–||1.000|
|Total US (TURis)||172||1 (0.6)||166||3 (1.8)||0.364|
|Grand Total US||564||12 (2.1)||562||15 (2.7)||0.553|
a Cumulative incidence rate at the end of follow-up.
b Partial rupture of bulbo-membranous urethra.
c Catheterization over guidewire and postponement of operation for 7–10 d.
d One patient required reoperation.
e A minimum follow-up of 12 mo (mean: 13.5) is reported, but it is stated that “long term complications such as US and BN contracture were the same at the end of 9 months in both groups.”.
BN = bladder neck; BU = bulbar urethra; MU = membranous urethra; na = not available; TURis = transurethral resection in saline; U = urethra; UI = urethral injury; UM = urethral meatus; US = urethral strictures; Vista CTR = Vista Coblation/controlled tissue resection.
Forest plots of long-term urethral complications at 12 mo of follow-up. CI = confidence interval; M-H = Mantel Haenszel.
3.6. Secondary end points
All trials recorded the duration of either the resection or the whole procedure. Mean operation times varied from 35 to 81 min in the M-TURP arm and from 39 to 79 min in the B-TURP arm. Due to large heterogeneity, no meta-analysis could be performed. This heterogeneity might be attributed to several operator-dependent or technical characteristics. Heterogeneous operator experience between arms, for example, could be a potential source of bias. In some trials, it was not clearly stated whether both arms were operated by the same surgeon , , , , and , while in three trials, more than one surgeon performed the operations , , and . Michielsen et al  found mean operation time to be statistically prolonged in the B-TURP arm, in accordance with a previous report on TURis . Operators’ heterogeneous experience between arms (6.7% of M-TURP procedures and 32.2% of B-TURP procedures were performed by trainees, and the rest were performed by staff members) was recognized later by the authors to have affected this result, and it was finally concluded that TURis is preferable . The smaller TURis loop diameter (5.4 mm × 2.6 mm vs 6.2 mm × 4.1 mm) might also explain this finding, since this characteristic imposes particular operator precision regarding hemostasis; experience is a requisite for this procedure , , and . In contrast, in other studies, no difference has been detected using the same system  and  or other systems , , , , , , , , , , and . A shorter operation time was even reported with PK .
Six trials reported on the duration of irrigation , , , , , and . In all trials but one , duration was longer in the M-TURP arm, and in three trials , , and , the result was statistically significant. Pooled analysis , , and  verified this result (WMD: 8.75 h; 95% CI, 6.8–10.7; p < 0.00001). Mean catheterization times ranged from 31.9 to 108 h in the M-TURP arm and from 18.4 to 96 h in the B-TURP arm. In seven trials , , , , , , and  out of 13 trials , , , , , , , , , , , , and  reporting on catheterization time, this factor was significantly longer in the M-TURP arm, but due to extreme heterogeneity (I2: 94%), no meta-analysis could be performed. This heterogeneity might be explained by the fact that different protocols for catheter removal (often insufficiently or not reported  and ) were seen in the included RCTs. Such protocols included prolonged catheterization in cases with larger prostates , catheter removal as soon as urine (completely) cleared , , , , , , , and , completely clear urine after 24 h without irrigation  and , and removal on a fixed postoperative day . Similarly, three trials , , and  out of the nine trials , , , , , , , , and  reporting on length of hospital stay showed a significantly quicker discharge (up to 48 h) in the B-TURP arm, but data could not be pooled due to large heterogeneity (I2: 98%). These outcomes were further evaluated by sensitivity and subgroup analyses.
3.7. Sensitivity, subgroup, and publication bias analyses
3.7.1. Sensitivity analyses
In an attempt to reduce a possible source of clinical heterogeneity among trials reporting on operation time, we performed a sensitivity analysis by selecting only trials in which all operations were performed by a single surgeon , , , , , , , and . Meta-analysis of five trials that reported on this outcome and could be pooled , , , , and  showed no significant difference in operation time (WMD: 2.4 min; 95% CI, −2.2 to 7.0; p = 0.30).
The decision for irrigation duration but mainly catheter removal and hospital discharge is multifactorial, with prior knowledge of the treatment offered potentially resulting in bias . Therefore, studies emphasizing these outcomes should be blinded for the outcome assessors. Only five RCTs clearly fulfilled this criterion (Table 2). Catheterization time appeared statistically shorter for the Vista Coblation/controlled tissue resection (CTR) system (ACMI, Southborough, MA, USA)  and for PK , , and  but not for TURis . Pooled analysis including only these trials in an attempt to exclude possible bias (Fig. 7) showed that the difference was significant in favor of B-TURP (WMD: 21.77 h; 95% CI, 19.22–24.32; p < 0.00001). Based on the same set of trials, inferences for hospital stay duration could not be made, since only one trial provided results suitable for a meta-analysis.
Forest plot of time to catheter removal (hours); sensitivity analysis including only trials reporting blinding of outcome assessors. CI = confidence interval; IV = inverse variance; SD = standard deviation.
3.7.2. Subgroup analyses
The various bipolar systems represent distinct technological advancements based on different electrophysiological principles regarding current flow. Consequently, efficacy and, principally, safety concerns should be cautiously and separately evaluated for each system  and .
We performed subgroup analyses to check for differences among the three systems evaluated in trials. First, we omitted trials using the Vista CTR system  and  because it is now removed from the market  and . This did not change the results. Additionally, we analyzed possible differences between the PK and TURis systems. Data on TURis were too few and heterogeneous to permit any safe conclusions. Generally, we did not observe any major effects on the meta-analyses of baseline and postoperative parameters.
In the trials that used the PK device, the number of patients requiring postoperative blood transfusions was slightly but significantly lower with B-TURP than with M-TURP (RD: 3%; 95% CI, 1–6%; NNH: 33; 95% CI, 17–100; p = 0.02) , , , , , , , and . Similarly, clot retention occurred slightly but significantly (p = 0.004) less frequently in patients after B-TURP with PK than after M-TURP (RD: 9%; 95% CI, 3–14%; NNH: 11; 95% CI, 7–33) , , , and . Meta-analysis of trials using the PK device did not change our results regarding operation and irrigation duration. Two trials using the PK device could be pooled  and , showing a significantly shorter catheterization time (WMD: 21.95 h; 95% CI, 18.27–25.62; p < 0.00001).
3.7.3. Publication bias analyses
We analyzed possible publication bias by generating funnel plots of the trials used for all of the evaluated comparisons of outcomes. No clear bias was apparent. As an example, we present the funnel plot of TUR syndrome occurrence showing no obvious asymmetry (Fig. 8).
Funnel plot regarding the occurrence of transurethral resection (TUR) syndrome. On the x-axis, the observed risk differences (RD) are shown for each trial; on the y-axis, the standard error (SE) for each risk difference is shown as a proxy for study size. The plot does not show large asymmetry, which would indicate missing trial results in a certain area.
Considering the two main limitations that may hamper our meta-analysis, namely, the low trial quality and the relatively limited follow-up, this systematic review provides the strongest available evidence, for the first time, showing that no clinically relevant differences in short-term efficacy exist between the two techniques. Furthermore, no differences were evident regarding operation time and rates of adverse events such as transfusions, retention after catheter removal, or urethral complications. B-TURP, however, is preferable, due to its more favorable profile, defined by the clinically relevant differences detected regarding complications such as TUR syndrome and clot retention. Additionally, irrigation and catheterization duration were significantly shorter with B-TURP, although it is not clear yet whether these differences can be translated into shorter hospital-stay duration. Between the two bipolar systems, PK has been submitted to a far more extended evaluation in RCTs, showing an improved safety profile. Data on TURis are not yet mature enough to permit safe conclusions. Data from well-designed multicentric/international RCTs with long-term follow-up (>12 mo) are welcomed, and a cost-analysis is still needed.
Author contributions: Jean J.M.C.H. de la Rosette had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Mamoulakis.
Acquisition of data: Mamoulakis, Ubbink.
Analysis and interpretation of data: Mamoulakis, Ubbink, de la Rosette.
Drafting of the manuscript: Mamoulakis.
Critical revision of the manuscript for important intellectual content: Ubbink, de la Rosette.
Statistical analysis: Ubbink, Mamoulakis.
Obtaining funding: None.
Administrative, technical, or material support: None.
Supervision: de la Rosette.
Other (specify): None.
Financial disclosures: I certify that all conflicts of interest, including specific financial interests and relationships and affiliations relevant to the subject matter or materials discussed in the manuscript (eg, employment/ affiliation, grants or funding, consultancies, honoraria, stock ownership or options, expert testimony, royalties, or patents filed, received, or pending), are the following: None.
Funding/Support and role of the sponsor: None.
Acknowledgment statement: The authors acknowledge Hanny Vriends (clinical librarian, Academic Medical Center, Amsterdam, The Netherlands), who provided assistance with the study search. Mrs. Vriends did not receive compensation for her contribution.
Dr. Charalampos Mamoulakis thanks the Alexander S. Onassis Public Benefit Foundation for a grant offered to attend a clinical fellowship program at the Academic Medical Center, Department of Urology, Amsterdam, The Netherlands.
Appendix A. Search strategy protocols used for each electronic database
- (1) Medline: (ablative OR minimally invasive[tw] OR plasmakinetic* OR plasmasect* OR PKRP OR turis OR vista OR gyrus OR wolf[tiab] OR storz[tiab] OR bipolar) AND (TURP[tw] OR Transurethral prostatectom*[tw] OR Transurethral prostate resection*[tw] OR “Transurethral Resection of Prostate”[Mesh] OR transurethral resection of the prostate[tw]) AND (((((((((((((((((((((volunteer*[tw]) OR ((prospectiv*[tw]))) OR ((control*[tw]))) OR ((prospective studies[mh]))) OR ((follow-up studies[mh]))) OR ((evaluation studies[pt]))) OR ((comparative study[pt]))) OR ((research design[mh:noexp]))) OR ((random*[tw]))) OR (((singl* OR doubl* OR trebl* OR tripl*) AND (blind* OR mask*)))) OR ((clinical trial[tw]))) OR ((clinical trials[mh]))) OR ((clinical trial[pt]))) OR ((single-blind method[mh]))) OR ((double blind method[mh]))) OR ((random allocation[mh]))) OR ((randomized clinical trials[mh]))) OR ((controlled clinical trial[pt]))) OR ((randomized controlled trial[pt]))) (the latter part is the Cochrane sensitive trials filter)
- (2) Embase: ablative.mp. OR minimally invasive.mp. OR plasmakinetic$ OR plasmasect$ OR pkrp OR turis OR vista OR gyros.mp. OR wolf.ti. OR wolf.ab. OR storz.ti. OR storz.ab. OR bipolar AND transurethral resection/ OR transurethral resection of the prostate.mp. OR transurethral prostate resection.mp. OR TURP OR transurethral prostatectom$.mp. AND Clinical Trial/ OR exp controlled clinical trial/ OR random$.mp. OR trial*.mp. (no search filter for Emabse at www.cochrane.nl)(mp.=multiple parts=all fields, .ti.=title, .ab.=abstract))
- (3) Science Citation Index: Topic=(ablative OR minimally invasive OR plasmakinetic* OR plasmasect* OR PKRP OR turis OR vista OR gyrus OR wolf OR storz OR bipolar) AND Topic=TURP OR Transurethral prostatectom* OR Transurethral prostate resection OR Transurethral Resection of Prostate OR transurethral resection of the prostate AND topic=Trial or trials
- (4) Cochrane Library: (ablative OR minimally invasive OR plasmakinetic* OR plasmasect* OR PKRP OR turis OR vista OR gyrus OR wolf OR storz OR bipolar):ti,ab,kw AND (TURP OR Transurethral prostatectom* OR Transurethral prostate resection* OR “Transurethral Resection of Prostate”[Mesh] OR transurethral resection of the prostate):ti,ab,kw
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a Department of Urology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
b Department of Quality Assurance and Process Innovation and Surgery, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
Corresponding author. Department of Urology (G4-105), AMC University Hospital, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands. Tel. +31 20 5666030; Fax: +31 20 5669585.
© 2009 European Association of Urology, Published by Elsevier B.V.