To compare the safety and efficacy of transurethral plasmakinetic resection of the prostate (PKRP) versus transvesical prostatectomy (TVP) in the treatment of large-volume benign prostatic hyperplasia (LV-BPH) (100–149 mL).
Ninety-nine BPH patients who had a prostate volume of 100–149 mL were divided into two groups to undergo PKRP or TVP. Preoperative clinical data were analyzed. Patients had follow-up appointments at 1 month, 3 months, 6 months, and 12 months postoperatively. Outcome measures included the International Prostate Symptom Score, quality of life score, maximum urinary flow rate, and postvoid residual urine volume. Adverse effects were also recorded.
A total of 96 patients completed the 12-month follow-up. The operative time was longer, but intraoperative blood loss was lower in the PKRP group. Despite a higher percentage of patients requiring a blood transfusion, there was an obvious advantage in gland removal rate in the TVP group. The duration of postoperative catheterization, bladder irrigation, and hospital stay was significantly shorter in the PKRP group. Outcome measures were significantly improved in both groups 1 month postoperatively. The improvement in lower urinary tract symptoms was maintained throughout the 12 months after surgery. There were no significant differences in International Prostate Symptom Score, quality of life, maximum urinary flow rate, and postvoid residual urine volume between the two groups.
PKRP has the advantage over TVP of being minimally invasive in the treatment of LV-BPH while achieving the same postoperative outcomes.
benign prostatic hyperplasia;large-volume prostate;transurethral plasmakinetic resection of the prostate;transvesical prostatectomy
Prostate volume is an important factor that affects the treatment of benign prostatic hyperplasia (BPH).1 Surgical treatment of large-volume BPH (LV-BPH) poses a challenge to urologists. Although transurethral resection of the prostate (TURP) is considered the “gold standard” for surgical treatment of BPH,2 the relatively long operative time, low efficiency of resection, and high incidence of postoperative complications (e.g., intraoperative and postoperative bleeding, postoperative hyponatremia, and urethral stricture) have limited its application in the treatment of LV-BPH.3 Open surgery is the main treatment option for LV-BPH because of its shorter operative time, complete gland removal, and significant postoperative improvement in lower urinary tract symptoms.4; 5 ; 6 However, given the advances in minimally invasive techniques, the use of traumatic open surgery for the treatment of LV-BPH is being increasingly disputed.7; 8 ; 9 Transurethral plasmakinetic resection of the prostate (PKRP) is a relatively new minimally invasive procedure that has been used for the treatment of LV-BPH.10 Having the advantages of accurate incision, good hemostasis, and “capsule recognition” function, PKRP can effectively prevent capsular perforation.11 Moreover, PKRP can avoid the occurrence of transurethral resection syndrome (TURS) because normal saline is used as the irrigation solution.12 Thus, PKRP is expected to replace TURP as the new “gold standard” treatment for BPH. However, there have been no previous studies evaluating the safety and efficacy of PKRP in the treatment of LV-BPH.
In the present study, we conducted a prospective randomized clinical trial to compare the safety and efficacy of PKRP versus transvesical prostatectomy (TVP) in the treatment of LV-BPH. Although many consider a large prostate volume as >80 mL or >100 mL, there remains a great deal of controversy about the definition of LV-BPH. The prostate volume in some BPH patients can be >500 mL.13; 14; 15; 16 ; 17 In this study, we attempted to define large and huge prostate volumes as 100–149 mL and >150 mL, respectively. For the purpose of this study, all BPH patients with prostate volume ranging from 100 mL to 149 mL were considered to have LV-BPH.
A total of 99 patients with LV-BPH (100–149 mL), who were treated from January 2005 to October 2010 at the Third Xiangya Hospital of Central South University, were included in this prospective trial. Preoperative clinical data for all the patients were analyzed, including age, medical history, International Prostate Symptom Score (IPSS), quality of life (QoL), digital rectal examination (DRE), prostate-specific antigen (PSA), maximum urinary flow rate (Qmax), prostate volume, postvoid residual urine volume (PVR), hemoglobin (Hb) concentration, and serum sodium (Na+) concentration. Transrectal ultrasound (TRUS) was used to measure the maximum length (L), width (W), and anteroposterior height (H) of the prostate to calculate the prostate volume using the prostate ellipse formula: prostate volume (mL) = 0.52 × L × W × H.18 Patients underwent an ultrasound-guided transrectal prostate biopsy if the PSA level was >4 ng/mL, the DRE was abnormal, or suspicious lesions were suggested by TRUS. Patients were given a thorough explanation about the advantages and possible risks of both modes of treatment. Written informed consent was obtained preoperatively from each patient. The included patients were divided into two groups by a urologist who was not involved in the surgery to undergo PKRP (n = 50) or TVP (n = 49). The study was approved by the local ethics committee.
The inclusion criteria were as follows: patients >60 years of age; able to tolerate surgery and anesthesia; not taking anticoagulant drugs or discontinuing anticoagulant drugs for ≥2 weeks; refusing to receive medical treatment or having failed in conservative medical treatment; QoL severely affected by lower urinary tract symptoms; one or more complications, such as recurrent urinary retention, gross hematuria, recurrent urinary tract infections, bladder stones, and secondary liquid accumulation in the upper urinary tract as a result of BPH; able to understand and sign informed consent; and able to complete follow-up as required. Exclusion criteria were neurogenic bladder; previous bladder, prostate or urinary tract surgery; urethral stricture; and known bladder or prostate cancer.
An experienced surgeon performed all surgeries. PKRP was performed using a bipolar plasmakinetic cutting wire loop (Gyrus Medical, Cardiff, UK) at a power setting of 160 W for cutting and 80 W for coagulation. A 0.9% sodium chloride solution was used to irrigate the area continuously. The 27F sheath was inserted to observe the changes in the urethral and bladder mucosa. According to the modified Nesbit procedure, an incision was made at the 6 o'clock position of the bladder neck to the proximal verumontanum to create a longitudinal marking groove that was extended to the verumontanum and carried down to the surgical capsule, with complete removal of the prostatic stroma. Then, another marking groove was made via an incision from the 11 o'clock to 1 o'clock position using the same method. Finally, the left and right lateral lobes of the prostate were removed from the 2 o'clock to 5 o'clock and 11 o'clock to 7 o'clock positions of the bladder neck. If the bladder neck was relatively high or there was a significant annulus around the bladder neck, part of the annulus was removed before the end of the procedure to eliminate the “doorsill phenomenon”. If bladder stones were present, transurethral cystoscopic holmium laser lithotripsy with a power of 80 W was performed before the PKRP procedure. A three-way 20F Foley silicone catheter was introduced at the end of the procedure. The TVP procedure was performed as previously described.19 An 8-cm longitudinal incision was made above the pubis to open the bladder. A circumferential incision was then made around the urethral orifice at the bladder neck to incise the bladder mucosa over the prostate and the prostate capsule. After blunt dissection of the prostate, the bladder was closed with a running 2-0 absorbable suture. A 28F mushroom-bladder catheter and a two-way 20F Foley silicone catheter were inserted after the procedure. The catheter balloon was filled with 30 mL water, and continuous traction of the bladder neck was performed for 6–12 hours. Continuous bladder irrigation was initiated in all patients until the irrigation solution became clear. The bladder catheter was removed when the color of the urine turned clear without continuous saline irrigation, while the urethral catheter was removed 2 or 3 days after bladder catheter removal when the fistula closed.
Postoperative outcome measures included the operative time of prostate resection (the operative time of holmium laser lithotripsy was not included); loss of Hb [g/dL Hb (preoperative) – g/dL Hb (at the end of the procedure)]; loss of Na+ [mmol/L Na+(preoperative) – mmol/L Na+ (at the end of the procedure)]; removed gland weight; gland removal rate (% weight removed/preoperative volume × 100); and the duration of continuous postoperative bladder irrigation, catheterization, and hospital stay. Intraoperative and postoperative complications were recorded, including blood transfusion, hemostasis, urethral stricture, hyponatremia, incontinence, urinary tract infections (colony count ≥105 colony-forming units/mL for clean midstream urine samples), and recatheterization. All patients were followed up at 1 month, 3 months, 6 months and 12 months postoperatively. Postoperative follow-up outcome measures included IPSS, QoL, Qmax, and PVR. During the follow-up period, one patient in the PKRP group could not be contacted after discharge. Two patients in the TVP group were lost to follow-up due to the change of address at 3 months and 12 months after surgery, respectively. Thus, a total of 96 patients (PKRP, n = 49; TVP, n = 47) completed the 12-month follow-up.
Statistical analysis was performed using SPSS 13.0 software package (SPSS, Inc., Chicago, IL, USA). Preoperative, perioperative, and postoperative data were expressed as mean ± standard deviation and compared using the Students t test. The incidence of postoperative complications was compared using the χ2 test, and p values <0.05 were considered statistically significant.
Ninety-nine patients with LV-BPH were initially enrolled in the study. Table 1 shows the preoperative clinical data for patients in the two groups, and there were no significant differences.
|PKRP (n = 50)||TVP (n = 49)||p|
|Age (y)||70.4 ± 6.4||71.3 ± 5.9||0.475|
|Medical history (mo)||69.8 ± 56.5||83.7 ± 48.6||0.195|
|Prostate volume (mL)||116.6 ± 12.6||118.2 ± 13.3||0.529|
|Qmax (mL/s)||4.9 ± 3.2||6.0 ± 3.1||0.087|
|IPSS||25.7 ± 7.9||26.6 ± 6.9||0.562|
|QoL score||4.9 ± 0.8||5.2 ± 0.9||0.115|
|PVR (mL)||70.3 ± 22.2||64.2 ± 18.9||0.150|
|Na+ (mmol/L)||139.8 ± 2.4||139.6 ± 2.8||0.608|
|PSA (ng/mL)||10.4 ± 9.8||12.1 ± 14.1||0.486|
|Hemoglobin (g/dL)||11.5 ± 1.3||11.2 ± 1.7||0.341|
IPSS = International Prostate Symptom Score; PKRP = plasmakinetic resection of the prostate; PVR = postvoid residual urine volume; PSA = prostate-specific antigen; Qmax = maximum urinary flow rate; QoL = quality of life; TVP = transvesical prostatectomy.
The perioperative results (Table 2) suggested that, although the operative time was 20.4 min longer for the PKRP group than the TVP group, the duration of bladder irrigation, catheterization and hospital stay was shorter in the PKRP group. There was more Hb loss in the TVP group, but the gland removal rate was 18.2% higher for the TVP group than the PKRP group. There was no difference in postoperative serum Na+ loss between the two groups.
|PKRP (n = 49)||TVP (n = 47)||p|
|Operation time (min)||75.8 ± 17.3||55.4 ± 11.3||<0.05|
|Tissue retrieved (g)||76.0 ± 12.6||98.7 ± 14.9||<0.001|
|Gland removal rate (%)||65.0 ± 6.9||83.2 ± 3.9||<0.001|
|Hb loss (g/dL)||1.2 ± 0.7||1.9 ± 0.9||<0.001|
|Na+ loss (mmol/L)||0.4 ± 0.5||0.3 ± 0.5||0.159|
|Irrigation time (d)||1.4 ± 0.6||2.4 ± 0.8||<0.001|
|Catheter removal (d)||5.6 ± 0.9||10.4 ± 1.2||<0.001|
|Hospital stay (d)||6.5 ± 0.8||11.5 ± 1.2||<0.001|
PKRP = plasmakinetic resection of the prostate; TVP = transvesical prostatectomy.
During the follow-up period, results showed that in both groups, the IPSS, QoL, Qmax, and PVR were all improved after surgery (Table 3). IPSS had a higher degree of improvementat 1 month postoperatively in the PKRP group than in the TVP group, but showed no significant differences at 3 months, 6 months and 12 months postoperatively between the two groups. The QoL, Qmax and PVR results showed no significant differences between the PKRP and TVP groups (Table 3).
|Baseline||1 mo||3 mo||6 mo||12 mo|
|PKRP||25.7 ± 7.9||9.5 ± 1.7||10.4 ± 1.2||9.0 ± 1.9||8.9 ± 1.6|
|TVP||26.6 ± 6.9||10.5 ± 1.5||10.5 ± 1.4||8.4 ± 2.4||8.8 ± 2.0|
|PKRP||4.9 ± 0.8||2.3 ± 0.5||2.1 ± 0.6||1.9 ± 0.5||2.0 ± 0.5|
|TVP||5.2 ± 0.9||2.5 ± 0.5||2.2 ± 0.6||2.1 ± 0.6||2.2 ± 0.6|
|PKRP||4.9 ± 3.2||14.7 ± 3.4||15.9 ± 3.9||16.5 ± 3.4||16.3 ± 3.2|
|TVP||6.0 ± 3.1||15.4 ± 4.1||16.7 ± 4.0||17.3 ± 3.8||17.4 ± 3.0|
|PKRP||70.3 ± 22.2||24.8 ± 5.6||21.6 ± 5.7||20.1 ± 5.3||19.0 ± 5.5|
|TVP||64.2 ± 18.9||25.9 ± 5.7||19.9 ± 5.7||18.8 ± 5.8||17.8 ± 5.4|
IPSS = International Prostate Symptom Score; PKRP = plasmakinetic resection of the prostate; PVR = postvoid residual urine volume; Qmax = maximum urinary flow rate; QoL = quality of life; TVP = transvesical prostatectomy.
The incidences of postoperative complications of the two groups are shown in Table 4. Intraoperative hyponatremia did not occur in either group. Postoperative urinary tract infections occurred in both groups, with an incidence of 4.1% in the PKRP group and 6.4% in the TVP group. No patients in the PKRP group required a postoperative blood transfusion, whereas three patients (all with Hb loss >5 g/dL) in the TVP group were transfused with 1–3 units of blood and underwent hemostasis treatment. Of the three patients who underwent blood transfusion, two required hemostasis via cystoscopic bladder blood clot removal surgery under continuous epidural anesthesia. However, there was no significant difference in the percentage of patients requiring blood transfusion between the two groups (p > 0.05). After catheter removal, three (6.1%) patients in the PKRP group and two (4.3%) in the TVP group could not urinate and required the catheter to be reinserted (p = 0.520). All of them could urinate 4–6 days later. After catheter removal, three (6.1%) patients in the PKRP group and four (8.5%) in the TVP group had mild urinary incontinence (p = 0.653). Through the utilization of pelvic floor muscle training, the urinary incontinence problem was resolved in all of them by 3 months postoperatively.
|PKRP (n = 49)||TVP (n = 47)||p|
|Blood transfusion||0||3 (6.4%)||0.072|
|Urethral stricture||3 (6.1%)||0||0.085|
|Temporary incontinence||3 (6.1%)||4 (8.5%)||0.653|
|Urinary tract infections||2 (4.1%)||3 (6.4%)||0.480|
|Recatheterization||3 (6.1%)||2 (4.3%)||0.520|
PKRP = plasmakinetic resection of the prostate; TVP = transvesical prostatectomy.
The PKRP group had a higher incidence of urethral stricture than the TVP group had (6.1% vs. 0, p = 0.085). Three patients in the PKRP group had a urethral stricture, including one case of urethral external orifice stricture and two cases of membranous urethral stricture. The patient with a urethral external orifice stricture underwent urethral dilatation. The patients with a membranous urethral stricture were treated by transurethral holmium laser incision with postoperative urethral dilatation on a regular basis (for 4–6 weeks). The postoperative recovery of urination was satisfactory. Qmax was >15 mL/s in all patients. In addition, no postoperative complications of other systems (i.e., pulmonary and cardiovascular systems) occurred.
TURP has comparable efficacy to open surgery in the treatment of small- and medium-volume BPH, but is associated with faster postoperative recovery and shorter hospital stay, which makes TURP the primary choice for surgical treatment of BPH. However, the application of TURP to the treatment of LV-BPH is limited due to the disadvantages mentioned in the Introduction section. Although open prostatectomy is considered to be the ideal treatment for LV-BPH,4; 7; 8; 9 ; 20 many BPH patients are reluctant to undergo open surgery due to trauma, bleeding, and the prospect of a long hospital stay. Gratzke et al9 performed open surgery on 902 BPH patients with an average prostate volume of 96.3 ± 37.4 mL and found that the total incidence of postoperative complications reached 17.3%. Of all patients tested, two (0.2%) died, 68 (7.5%) received a blood transfusion, 46 (5.1%) contracted a urinary tract infection, and 33 (3.7%) had severe bleeding.
PKRP is a new form of TURP that is applicable in the majority of BPH patients with bladder outflow obstruction.21; 22; 23 ; 24 The formation of a highly focused ionized plasma area around the electrodes leads to quick cutting action and the formation of a uniform solidified layer, 3–5 mm in depth, that functions in hemostasis.25 ; 26 There is no need for the use of a negative plate during surgery, and no current flows through the body. Therefore, PKRP is particularly suitable for patients with a pacemaker. The biggest advantage of PKRP is the use of 0.9% normal saline as the irrigation medium, which has little effect on the internal environment of the body.27 Therefore, PKRP can effectively prevent the occurrence of TURS.28 Moreover, the cutting action of PKRP is related to the resistance of the tissue. As the resistances of hyperplastic gland and capsule are somewhat different, the capsule is resected with relatively low efficiency. Therefore, it is difficult to cut through the capsule, which further reduces the risk of developing TURS.12 In our clinical trial, although the operative time of PKPR was longer than that of TVP (75.8 ± 17.3 minutes vs. 55.4 ± 11.3 minutes, p < 0.05), there was less intraoperative loss of Hb (1.2 ± 0.7 g/dL vs. 1.5 ± 0.9 g/dL, p < 0.05) in the PKPR group, and none of the patients in the PKPR group required a blood transfusion, suggesting that PKPR is a minimally invasive procedure compared to TVP.
The surface temperature of plasma is <70°C when it acts on prostate tissue. With this small thermal effect, PKPR has the advantage of not easily damaging the verumontanum and external sphincter (especially the erectile nerves). Therefore, the incidence of postoperative bladder irritation is decreased. Moreover, the incidence of secondary hemorrhage and urinary tract infections resulting from tissue necrosis also decreases, which is conducive to postoperative recovery. Consistent with these facts, our results show that the duration of postoperative bladder irrigation, catheterization, and hospital stay was significantly shorter in the PKRP group than in the TVP group (1.4 ± 0.6 days vs. 2.4 ± 0.8 days, 5.6 ± 0.9 days vs. 10.4 ± 1.2 days, 6.5 ± 0.8 days vs. 11.5 ± 1.2 days; p < 0.001 for all). This observation is in agreement with the result of a recently published study. 29 Taken together, these findings suggest that PKRP has an advantage over TVP in terms of faster postoperative recovery in the management of LV-BPH.
Although the removal efficiency of PKRP was lower than that of TVP (65.0 ± 6.9% vs. 83.2 ± 3.9%, p < 0.001), there was no difference in the improvement in urination between the two groups. Patients in both groups had significant improvement in urinary function scores, except for IPSS at 1 month follow-up (9.5 ± 1.7 (PKRP) vs. 10.5 ± 1.5 (TVP), p = 0.002). The improvement in lower urinary tract symptoms in both groups was maintained during the postoperative follow-up from 3 months to 12 months, showing no significant difference between the two groups (p > 0.05). One previous clinical trial comparing the transurethral plasmakinetic enucleation of the prostate and PKRP showed that IPSS, QoL, Qmax, and PVR were all significantly improved 3 months postoperatively and that there were no differences between the two groups. 30 Therefore, as long as the median and both lateral lobes of the hyperplastic gland are effectively removed during PKRP, which eliminates bladder outlet obstruction and lower urinary tract symptoms, PKRP can achieve the same efficacy as TVP, even if it does not reach the gland removal rate of TVP.
Although PKRP has a significant advantage of being minimally invasive compared to TVP, the incidence of urethral stricture associated with the PKRP procedure could not be neglected in our study (6.1% for the PKRP group). The preoperative presence of urethritis, a relatively large plasmakinetic resectoscope sheath (it may be a little too large for Asians), the long duration of the irritation of the mucous membrane of the urethra during surgery, and the surgeons rough handling were all likely to be the reasons for urethral injury. The main sites of injury were the urethral external orifice and the membranous urethra. Both the failure to complete timely repair of urethral injury and irritation from complicated postoperative urethritis could cause urethral stricture. Once the urethral stricture was confirmed, remedies including the incision of the stricture ring and regular urethral dilatation should be used. Effective measures to reduce the incidence of urethral stricture include preoperative objective assessment of the patients urethral condition by urinary tract imaging, the avoidance of rough handling during surgery, shortening operative time, and active postoperative antibiotic usage. Timely urethral dilatation for patients that may have urethral stricture could reduce the risk of having to undergo a subsequent transurethral surgery.
The incidence of other adverse events, such as temporary urinary incontinence (6.1% for PKRP vs. 8.5% for TVP), urinary tract infections (4.1% for PKRP vs. 6.4% for TVP), and recatheterization (6.1% for PKRP vs.4.3% for TVP), showed no significant differences between the PKRP and TVP groups (p > 0.05 for all). The main reasons for temporary urinary incontinence may be related to local inflammatory edema, a failure of the external sphincter mechanism, bladder instability or a decrease in bladder compliance, and excessive elongation of the external sphincter due to long-term compression from the hyperplastic gland. In our study the urinary incontinence was not caused by sphincter damage. Through a period of pelvic floor muscle training, all of the patients were able to recover on their own.
Besides PKRP, there are several other effective and minimally invasive treatments currently available for prostatectomy to minimize the chance of bleeding and TUR syndrome, such as transurethral laser prostatectomy and photoselective vaporization.31 Most of the lasers for prostatectomy have lower bleeding and less water toxicity than TURP has.31 ; 32 In particular, laser enucleation of the prostate is as effective as open prostatectomy in the management of very large prostate glands.32 Compared with PKRP, holmium laser enucleation of the prostate is associated with less risk of hemorrhage, shorter bladder irrigation and catheter times, and reduced hospital stay.33 Of note, although traditional TURP using distilled water in managing LV-BPH carries a higher risk of TURS due to prolonged operation time, and PKRP can compensate for this weak point, distilled water provides better vision than normal saline and enables a quicker procedure that leads to less bleeding and less water shifting into the body. With regard to the fact that TURS does not have a high incidence and can be treated with intraoperative diuretics, PKRP is not inferior to TURS alone. However, combination of PKRP with laser vaporization may combine the advantages of both techniques and provide a safer and more effective method for the treatment of LV-BPH.34
The current study was limited in that patients were not randomly assigned, which may have led to imbalances in risk factors between the two groups and biased estimates of treatment effects. Another limitation of our study was the relatively small sample size with limited statistical power. Finally, the follow-up time was relatively short. Future studies should be carefully designed to address these issues.
In conclusion, our clinical trial shows that PKRP has the advantage of being minimally invasive over TVP in the treatment of LV-BPH (100–149 mL), while achieving the same postoperative outcomes. Therefore, PKRP is a safe and effective treatment method for LV-BPH. However, future studies with more patients and a longer follow-up time are needed to evaluate further the safety and efficacy of PKRP.
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