Bipolar transurethral vaporization : a superior procedure in benign prostatic hyperplasia : a prospective randomized comparison with bipolar TURP

ARTICLE INFO ______________________________________________________________ ______________________ Objective: To compare the outcomes of bipolar transurethral vaporization of the prostate (TUVP) with bipolar transurethral resection of the prostate (TURP). Materials and Methods: In a prospective randomized trial, 88 patients with moderate to severe lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH) underwent bipolar TUVP (N = 39) or bipolar TURP (N = 49) from October 2010 to November 2011. The inclusion criteria were age > 50 years, prostate volume of 30-80mL, serum PSA < 4ng/mL, IPSS ≥ 20, Qmax ≤ 10mL/s and failed medical therapy. The perioperative and postoperative outcomes were evaluated and the IPSS and Qmax were assessed preoperatively and 3 months after procedure in all cases. Results: Both groups were similar in patient age, prostate volume, preoperative IPSS and Qmax. The TUVP group had significantly lower mean values of operative time, hospital stay, catheterization period, irrigation fluid volume and serum hemoglobin, creatinine, sodium and potassium changes compared with TURP group. No significant differences were seen between two groups regarding complications (TUVP = 10.3%; TURP = 12.2%) and modified Clavien classification of complications. No TUR syndrome, obturator reflex or epididymitis occurred in both groups. Re-hospitalization and transfusion due to clot retention (N = 2) and urethral stricture (N = 1) were reported only in the TURP group. Three patients experienced urinary retention after catheter removal in the TUVP group. Two patients were re-catheterized temporarily and one patient required repeat bipolar TUVP. Three months after surgery, two groups had significant improvement in IPSS and Qmax. But the TUVP group had significantly lower IPSS and higher Qmax than TURP group. Conclusions: Bipolar TUVP is a safe, effective and low cost procedure among minimally invasive surgeries of BPH. Compared with bipolar TURP, the bipolar TUVP had similar complications, better perioperative and postoperative outcomes, superior hemostasis and higher efficacy.

Bipolar technology using saline conductive medium accompanies with proper translucency, similar osmolality to the serum, minimal risk of dilutional hyponatremia and TUR syndrome, larger removal of prostate tissue, smaller coagulation depth, longer time for safe resection and coagulation, less tissue damage due to lower energy, and lower temperature and thermal damage (7,8,12,15,19,27,28). Nowadays, bipolar TURP is used in many centers due to several benefits and superior or similar results in comparison with monopolar TURP (8,14,23,(29)(30)(31).Bipolar transurethral vaporization of the prostate (TUVP) in saline using hovering technique is an easy learning and low cost procedure in comparison to laser technique (12,14,20).Bipolar TUVP provides suitable depth of coagulation, high hemostasis and proper outcomes in comparison with monopolar TUVP and monopolar TURP (7,14,20,24,26,(32)(33)(34).
In this study, we compared the perioperative and postoperative outcomes of bipolar TUVP and bipolar TURP in a prospective randomized trial in patients with moderate to severe LUTS secondary to BPH.

MATERIALS AND METHODS
From October 2010 to November 2011, 88 patients underwent bipolar TUVP (B-TUVP, N = 39) or bipolar TURP (B-TURP, N = 49) in a single--center prospective randomized trial who were referred for surgical management of moderate to se-vere LUTS secondary to BPH.All procedures were performed successfully by single surgeon under spinal anesthesia.Local ethical committee approved this research.Before operation, all patients were assessed by medical history, general physical and regional neurological examinations, digital rectal examination (DRE), laboratory tests (CBC, hemoglobin and hematocrit, coagulation tests, serum prostate specific antigen [PSA], ESR, BUN, serum creatinine and electrolytes [sodium, potassium], urine analysis, urine culture and sensitivity test), abdominal ultrasonography (including measurement of the prostate volume), international prostate symptom score (IPSS) questionnaire and uroflowmetry (measurement of maximum flow rate [Q max ]).
The inclusion criteria were age > 50 years, prostate volume of 30-80mL, serum PSA < 4ng/ mL, IPSS ≥ 20, Q max ≤ 10mL/s and failed BPH-related medical therapy.The exclusion criteria were abnormal DRE or ultrasonography with suspicion of prostate cancer, history of prostate cancer, serum PSA ≥ 4ng/mL, previous urethral or prostate surgery, urethral stricture, neurogenic bladder, bladder calculi, BPH-related hydronephrosis, anticoagulant therapy, coagulation disorders, renal insufficiency and severe co-morbidities or co--existing diseases.
The procedures were accomplished under direct sight by continuous flow irrigation with normal saline (0.9% NaCl), the Olympus bipolar generator (cutting: 280 W; coagulation: 125 W), the classical and traditional surgical steps of transurethral resection in saline (TURis) for TURP and hovering technique for TUVP.A standard resection loop and a "button-type" vaporization electrode were used for TURis and vaporization without resection respectively.In all patients, a 20-24Fr three-way Foley catheter was placed at the end of the procedure.
The parameters including operative time, irrigation fluid volume, catheterization period, postoperative hospital stay, complications and postoperative changes in hemoglobin, serum creatinine, sodium and potassium levels were assessed in all patients.Also three months after procedure, the IPSS and Q max were measured for evaluation of efficacy in all cases.
Software SPSS version 16.0, independent t test, Mann-Whitney test, Chi-square test, Fisher Exact test and Wilcoxon test were applied for statistical analysis and P-value < 0.05 was considered significant.

RESULTS
The mean patients' age, values of prostate volume, IPSS and Q max are mentioned in Table -  The overall complication rate was 10.3% in the B-TUVP group and 12.2% in the B-TURP group.No significant differences (P > 0.05) were seen in overall complications and modified Clavien classification of complications between the B-TUVP and the B-TURP groups.Low grade self--limited fever occurred in one patient (2.6%) of the B-TUVP group and in three patients (6.1%) of the B-TURP group and this difference was non--significant (P = 0.626).No TUR syndrome, obturator reflex or epididymitis were seen in both groups.Two patients (4.1%) experienced postoperative hematuria and clot retention during one week after B-TURP procedure and were re-hospitalized.These patients were treated by bladder fluid irrigation and required blood transfusion.Urinary retention occurred after catheter removal in the three patients who underwent B-TUVP.Two patients were re-catheterized for a short period and one patient re-treated with repeat B--TUVP.During a three month follow-up, urethral stricture occurred only in one patient following B-TURP who was treated by endoscopic urethral dilation (Table -3).
Three months after procedure, significant (P < 0.001) improvement in the mean values of IPSS and Q max were seen in the B-TUVP and the B-TURP groups.But the B-TUVP had significantly higher efficacy compared with B-TURP.The B-TUVP group (2.56 ± 2.58) had significantly (P < 0.001) lower mean IPSS than the B-TURP group (5.49 ± 3.40).Also in the B-TUVP group (23.23 ± 1.08mL/s), mean Q max was significantly (P < 0.001) higher than B-TURP group (20.79 ± 1.47mL/s) (Table -2).
Increase in life expectancy and higher prevalence of surgical risk and comorbid diseases such as cardio-pulmonary diseases, coagulation disorders and anti-platelet or anticoagulant therapies in the old patients may lead to the limitation in the use of bipolar TURP (3,18).Also fluid absorption betides in the bipolar TURP and volume overload may be problematic in patients with severe cardio-pulmonic disorders (23,27,31,36).In the last decade, laser energy has been applied with high safety and efficacy for vaporization or enucleation of hypertrophic large volume prostate (6,9,(11)(12)(13)(40)(41)(42).
But laser therapy may be accompanied with the use of multiple techniques and different wattage, technical complexity, prolonged operative time, higher applied energy and re-operation rate in the larger prostate volume cases, high cost equipment and inaccessibility in many centers (6,9,(11)(12)(13)(40)(41)(42).Beside morbidity and complication, attention to other outcomes, prostate volume, anesthesia risk, patient satisfaction, cost-benefit or cost--effectiveness, learning curve, easy accessing and performing is important in the selection of preferable procedure.
The operating time had the means of 61 and 63 minutes for B-TUVP and the median of 55 minutes for bipolar plasmakinetic electrovaporization in the published experiences (12,20,45).In Dunsmuir and co-workers trial, the bipolar electrovaporization and TURP had similar operation time (33 vs. 26 minutes, P = 0.78) (16).Hon et al. reported longer mean resection time for PKVP compared with standard TURP (32.6 vs. 28.5 minutes, P = 0.08) (17).But in other studies, the PKVP (40.3 vs. 55 minutes) (47) and bipolar plasmakinetic vaporization-resection (40.3 vs. 57.8minutes, P < 0.01) (19) had shorter mean operative time than TURP.In the different meta-analysis studies, the operative time was similar between B-TURP and M-TURP (31) but the operative time in the PVP was longer than TURP (6).Ahyai et al. reported the shortest mean operation time (36 minutes) for B-TUVP among minimally invasive surgical therapies (14).Also in Geavlete et al. comparison, the mean operation time in the B-TUVP (39.7 minutes) was significantly (P = 0.0001) shorter than B-TURP (52.1 minutes) and M-TURP (55.6 minutes) (34).In our trial, B-TUVP had shorter mean operative time (25.92 vs. 32.63minutes) compared with B-TURP.This result can be explained by easy performance, good hemostasis and coagulation, better sighting due to decreased hemorrhage, the lack of vacating resected samples and possible proper vaporization of prostatic tissue during moving of the electrode in the B-TUVP (12,34).
The mean values of pre-and postoperative serum sodium were 141.3 and 140.6mmol/L and no serum electrolyte abnormality occurred in Reich et al. experience in B-TUVP (12).In Otsuki et al. report the irrigation fluid volume was 22.9 liters and the B-TUVP had similar pre-and postoperative serum sodium level (20).Mamoulakis et al. reported signi-ficantly higher sodium level for B-TURP compared with M-TURP (31).In Dunsmuir and co-workers trial, bipolar electrovaporization and TURP had similar postoperative serum sodium level (16).Also similar sodium changes and perioperative fluid absorption were reported for PKVP and TURP in Hon et al. study (17).The bipolar plasmakinetic vaporization-resection had significantly lower mean perioperative irrigation fluid volume compared with TURP (11.4 vs. 18.3 lit) in Tefekli et al. comparison (19).In our study, the mean values of irrigation fluid volume (10.74 vs. 14.22 lit), serum sodium (1.71 vs. 2.29meq/l) and potassium (0.22 vs. 0.31meq/l) changes in the B-TUVP were lower than B-TURP.Reduced hemorrhage, superior sight and performing the operation without resection and sampling, decrease irrigation fluid volume, subsequent fluid absorption and serum electrolytes changes in the B-TUVP compared with B-TURP (12,34).
The published studies have reported significant improvement in IPSS and Q max with different follow-up durations for vaporization and vaporization-resection (including bipolar technology) in the case series (12,20,44,45) or in comparison with monopolar or bipolar TURP (19,34,43,(46)(47)(48) and our results are similar to those.In the meta-analysis studies, the PVP and B-TURP had similar results with M-TURP regarding IPSS and Q max especially in the short-term follow-up (6,14,22,31) Otsuki and co--workers reported significant improvement in IPSS between three months and one month after B-TUVP (8.8 vs. 11.1),but this matter wasn't proved about Q max (15.2 vs. 15.1mL/s)(20).Karaman et al. reported significantly higher improvement of IPSS for PKVP compared with TURP on postoperative month 3 and both groups had similar Qmax values (47).In Tefekli et al. comparison, the bipolar plasmakinetic vaporization-resection had significantly higher improvement in Q max (120.5% vs. 103.6%)compared with TURP at 12 months after operation (19).But both groups had similar improvement regarding IPSS (63% vs. 64.3%)(19).But in Kaya et al. comparison, the TURP had significantly better result of IPSS (5.2, 5.7 vs. 7.1, 7.6) and Q max (20.8, 21.8 vs. 12.5, 14.4mL/s) than PKVP at 24 and 36 months after operation (43).Furthermore, no significant di-fferences were seen in efficacy (based on IPSS and Q max ) between vaporization (including bipolar technology) and TURP in multiple studies (14,16,17,48).In Geavlete et al. trial, the B-TUVP had significantly better results of IPSS and Q max compared with B--TURP and M-TURP during 18 months of follow-up (34).Also in our trial, the B-TUVP had significantly higher improvement in postoperative IPSS (2.56 vs. 5.49) and Q max (23.23 vs. 20.79mL/s)compared with B-TURP.Proper visibility due to lesser bleeding and formation of suitable cavity with good margins and surface in the operated area can explain this result with B-TUVP (34).We believe that TUVP can be a good alternative for TURP or even laser, because of lesser bleeding during the surgery and low cost of the equipments.

CONCLUSIONS
Bipolar TUVP is a safe, effective and low cost procedure in the endoscopic minimally invasive surgical management of BPH.Compared with bipolar TURP, the bipolar TUVP had similar complications and significantly better perioperative and postoperative outcomes (including shorter operative time and postoperative hospitalization and catheterization periods, lower irrigation fluid volume and serum sodium and potassium changes), superior hemostasis (due to lower hemoglobin drop) and higher efficacy (because of superior improvement in postoperative IPSS and Q max ).However, more studies are needed with large amount of patients to corroborate our results.

Table 1 -Patient-and operation-related parameters in Bipolar TUVP and Bipolar TURP groups.
§ SE = Standard error of mean; * = Mann-Whitney test; § = Independent T test