A Study Comparing Plasmakinetic Enucleation with Bipolar Plasmakinetic Resection of the Prostate for Benign Prostatic Hyperplasia

Abstract

Background and Purpose:

Plasmakinetic enucleation of the prostate (PKEP) has been reported to be a new method for the transurethral management of benign prostatic hyperplasia (BPH). Our objective was to compare the safety and efficiency of PKEP with that of bipolar plasmakinetic resection of the prostate (PKRP) in the management of BPH.

Patients and Methods:

A total of 303 patients with lower urinary tract symptoms associated with BPH were included in our study. Of these, 143 patients underwent PKRP and 160 underwent PKEP. All patients were preoperatively assessed and evaluated at 3 months after surgery. International Prostate Symptom Score (IPSS), quality of life (QoL), postvoid residual urine (PVRU) volume, and maximum flow rate (Qmax) were obtained at the follow-up. The perioperative data and postoperative outcomes were compared. Immediate and late complications were recorded.

Results:

There were no significant differences between the two surgical groups preoperatively. The mean prostate volumes in the PKRP and PKEP groups were 75.6 cc and 77.3 cc, respectively. Both groups were similar with respect to operative time, resected tissue weight, catheterization time, and the total length of hospital stay. The blood loss observed in the PKEP group was significantly less than that of conventional PKRP (P<0.0001). PKEP was significantly superior to PKRP in terms of the transient incontinence in the postoperative period (P=0.03). Both groups resulted in a significant improvement from baseline in terms of IPSS, QoL, Qmax, and PVRU volume values. No significant difference was found between them, however.

Conclusions:

PKEP is a safe and effective method for the transurethral management of BPH. Compared with PKRP, the main advantage of PKEP is the decreased risk of blood loss and transient incontinence.

Introduction

B enign prostatic hyperplasia (BPH) is a frequent urologic disease, which can result in lower urinary tract symptoms (LUTS) in aging men. It has been reported that at least 15 million persons worldwide have BPH.¹ Approximately 10% of men with BPH receive that diagnosis before the age of 40 years, with up to 80% over 40 years old; 50% of them have some symptoms of bladder-outlet obstruction at the age of 60, which increases to 90% by the age of 85.^1,2

The cause of BPH is still unknown. Factors linked to increase in age may play a role in the growth of the gland, however.¹ Research indicates that the presence of normally functioning testicles may be a risk factor, and castration can reduce enlarged prostates. It is supposed that the tumor tissue uses the male hormones differently compared with the normal prostate.³

Currently, there are many types of therapy available for patients with BPH, ranging from medical management to surgery, including watchful waiting, drug therapy, minimally invasive treatments, and open prostatectomy. Transurethral resection of the prostate (TURP), which accounted for almost 25% of all urologic operations, is currently the best choice for symptomatic BPH.⁴ Complications and morbidity related to the conventional TURP, however, are still significant, such as blood loss, fluid balance disturbances, urethral stricture, and incontinence.⁵ Some rare complications, such as pacemaker malfunction, can also be caused by the use of monopolar diathermy.⁶

In the era of minimally invasive treatment, various new technologies have been developed that aim to minimize the morbidity of TURP. Recently, the Gyrus PlasmaKinetic (PK) System, which is the first bipolar device used in urological practice, gained worldwide attention.⁷ The transurethral plasmakinetic resection of the prostate (PKRP) provides a new minimally invasive surgical option for the management of BPH that enables the resection of tissue by creating an ionized plasma corona using an axipolar electrode and electroconductive solutions.^7,8 The PK system uses saline as an irrigant rather than glycine or sorbitol and thus minimizes the risks of perioperative bleeding and transurethral resection (TUR) syndrome, which are great concerns during TURP.⁹ Increasing numbers of clinical trials comparing PKRP and TURP have been published. Compared with conventional TURP, PKRP has been accepted as a safer and more effective therapy for the obstructive uropathy induced by BPH.^9,10

This technique has been further refined by the development of PK technology that allows enucleation of whole lobes of the prostate, as reported by Neill and coworkers.¹¹ It has been claimed that PK enucleation of the prostate (PKEP) is technically feasible and a safe procedure that can reduce many of the problems associated with PKRP.^11,12 No studies has been reported, however, to evaluate the safety and efficiency of PKEP in a large sample size.

We report clinical results that compare PKEP and PKRP in 303 patients with outflow tract obstruction from BPH. To our knowledge, this study is the first report that compares PKEP with PKRP.

Patients and Methods

Patients

We retrospectively studied 303 patients whose complaints of severe LUTS necessitated surgical intervention in our department between January 2007 and January 2008. Of these, 143 patients underwent PKRP and 160 underwent PKEP. The inclusion criteria were the urinary peak flow rate (Qmax) less than 15 mL/s, International Prostate Symptom Score (IPSS) ≥14, medical therapy failure, and transrectal ultrasonography (TRUS) adenoma volume less than 100 g. A ultrasonography-guided prostatic biopsy was performed to exclude prostate cancer when necessary. Patients with a history of receiving anticlotting drugs; a known neurogenic bladder; any urethral, bladder neck, or prostatic surgery; and the presence of an indwelling catheter were not included in this study.

The median ages of the patients in the PKRP and PKEP groups were 74 years (range 62–86 years) and 76 years (range 61–91 years), respectively. The mean prostate volumes were 75.6 cc (range 50–89 cc) in the PKRP group and 77.3 cc (range 56–95 cc) in the PKEP group. After a routine physical examination and digital rectal examination, symptom scores and quality of life (QoL) index were graded using the IPSS index for each patient. TRUS was performed to determine the prostate volumes. Postvoiding residual urine (PVRU) measurement and Qmax were also recorded preoperatively.

Surgical procedures

The study protocol was approved by the locally responsible ethics committees. Every patient was informed of all the complications that may occur during this study, and only patients who provided written informed consent were included in this research. All of them were operated on by the same surgeon and received preoperative antibiotics. Physiologic saline was used as the irrigation fluid. All patients received epidural or regional anesthesia and were placed in the lithotomy position.

In both PKRP and PKEP applications, the Gyrus Plasmakinetic SuperPulse System (consisting of a PK generator, a PK resectoscope, and a PlasmaSect electrode) was used. The generator features a 200-W capability, and the radiofrequency range is between 320 and 450 kHz with a security interval of 350 to 450 V. Once connected, it automatically operates using preprogrammed settings (160 W for cutting and 80 W during coagulating). The power level can be changed by the physician if necessary.

At the beginning of the procedure, the continuous 24F resectoscope was inserted into the bladder to assess the range between bladder neck and verumontanum, and the ureteral orifices and prostatic adenoma were also visualized. Then, we started PKRP with the resection of the median lobe, if it was encountered. In such cases, a longitudinal groove was first made at the 6 o'clock position, from the bladder neck to proximal of the verumontanum. To make sure the prostatic stroma can be removed completely, the incision must be made deep into the surgical capsule. If the median lobe was not present, however, this initial procedure could be omitted, and a lateral right groove should be performed at the 11 o'clock lithotomy position, as described by Nesbit.¹³

In PKEP, the proximal border of the verumontanum and the distal margins of the prostate lobes were marked first with a cutting loop. After incision of the mucosa, a circular incision was made by deepening the incision along the marks until the surgical capsule was reached. Then, a cleavage plane between the surgical capsule and detached lobe was made by inserting the tip of the resectoscope from the circular incision line at the 5 and 7 o'clock positions. Similar to the surgeon's index finger in open prostatectomy, the resectoscope sheath was moved under the adenoma and bluntly shifted toward the lateral and forward sides, thereby mechanically dissecting the prostatic adenoma away from surgical capsule in a retrograde approach from the prostate apex toward the bladder. Bleeding during these procedures can be handled easily with coagulation. After this, the entire prostate was bluntly exposed and devascularized but still attached to the bladder neck with a narrow pedicle. Finally, the devascularized prostate was resected into pieces very rapidly and bloodlessly with the PK cutting loop, resulting in a real ‘‘in situ’’ morcellation.

After the resection was completed, the operative time and resected tissue weight were recorded. Intraoperative blood loss was estimated by the following formula: Blood loss (mL)=hemoglobin in fluid/hemoglobin of patient×volume of irrigation fluid (mL). A triple lumen catheter was placed into the bladder, and the saline irrigation was started until the catheter drainage became clear. After the irrigation had been stopped for a minimum of 6 hours, the catheters were removed if the urine color was still satisfactorily light, and the patients were then discharged from the hospital within 24 hours after decatheterization. The time of catheter removal and the length of the hospital stay were noted. All immediate or early complications were recorded, and a short course of oral antibiotics was continued after the patients were discharged. After 3 months, a follow-up was conducted, and the values of IPSS, QoL, PVRU, and Qmax were measured and compared with the preoperative values.

Statistical analysis

The baseline characteristics and perioperative data were statistically analyzed with the Student t test and presented as the mean±standard deviation (SD). The two-tailed chi-square test was used to compare the postoperative adverse events. Statistical analysis was performed with Statistical Package for Social Sciences, version 12.0 for Windows analytical software. Statistical significance was considered at P<0.05 for all analyses.

Results

The groups were homogenous for age, prostate volume, IPSS, QoL, Qmax, and PVRU preoperatively. The histopathologic evaluation was BPH in all PKEP and PKRP cases. Comparing the preoperative parameters, no statistical differences were found between the two groups. The mean operative time was less in the PKEP group (71±15.4 min) than in the PKRP group (76±13.5 min). No statistical differences were found between them (P=0.09), however. Similarly, there was no significant difference in the mean resected tissue weight (47 vs 51 g, P=0.16), catheterization time (4.1 vs 3.9 days, P=0.13) and total hospital stay (9.3 vs 8.7 days, P=0.11). The blood loss observed in the PKEP group and conventional PKRP group were (146±48.6 mL) and (254±76.4 mL), respectively, which was statistically significant (P<0.0001). None of the patients needed blood transfusion in both groups (Table 1).

Table 1.

Perioperative Data (Mean±Sd)

	PKRP	PKEP
	(N=143)	(N=160)	P value
Operative time (min)	76±13.5	71±15.4	0.09
Blood loss (mL)	254±76.4	146±48.6	<0.0001
Resected tissue (g)	47±13.1	51±14.3	0.16
Catheter time (days)	4.1±1.2	3.9±1.1	0.13
Hospitalization time (days)	9.3±3.4	8.7±3.1	0.11

Results assessed statistically using the Student t test.

SD=standard deviation; PKRP=plasmakinetic resection of the prostate; PKEP=plasmakinetic enucleation of the prostate.

All patients were followed up for 3 months postoperatively, and the complications were recorded (Table 2). Secondary bleeding was seen in two (1.4%) patients in the PKRP group and in three (1.6%) patients in the PKEP group after removal of the catheters. These patients were treated with a repeat cystoscopy. A total of 23 patients (16.1%) in the PKRP group and 12 patients (7.5%) in the PKEP group complained of some degree of urinary incontinence. These patients received the diagnosis of transient incontinence using urodynamic evaluation, and all of them improved over 2 months. Urethral stricture occurred in five (3.5%) patients in the PKRP group and four (2.5%) patients in the PKEP group. All these urethral strictures recovered with urethral dilation in the office.

Table 2.

Number (%) of Patients Presenting With Complications

	PKRP	PKEP
Complication	(N=143)	(N=160)	P value
Secondary bleeding	2 (1.4)	3 (1.6)	0.89
Transient incontinence	23 (16.1)	12 (7.5)	0.03
(2 months PO)
Urethral stricture	5 (3.5)	4 (2.5)	0.96
(3 months PO)

Results assessed statistically using the two-tailed chi-square test.

PKRP=plasmakinetic resection of the prostate; PKEP=plasmakinetic enucleation of the prostate; PO=postoperative.

Table 3 lists the treatment efficacy. At the 3 months follow-ups, both groups had significant improvement from baseline in terms of IPSS, QoL, Qmax, and PVRU values. No significant difference was found between them, however.

Table 3.

Assessment of Functional Results at the 3-Month Postoperative Follow-Up (Mean±Sd)

	Preoperative	Postoperative 3 months
IPSS
PKRP	22±5.3	6.4±1.7
PKEP	21±5.5	6.1±1.3
P value	0.11	0.42
QoL score
PKRP	5.3±0.6	1.5±0.8
PKEP	5.6±0.5	1.3±0.5
P value	0.18	0.49
Qmax (mL/s)
PKRP	8.2±2.5	24±4.6
PKEP	7.5±2.3	25±4.3
P value	0.22	0.63
PVRU volume (mL)
PKRP	126±35	22±9.2
PKEP	132±38	23±8.9
P value	0.16	0.34

Results assessed statistically using the Student t test.

SD=standard deviation; IPSS=International Prostate Symptom Score; PKRP=plasmakinetic resection of the prostate; PKEP=plasmakinetic enucleation of the prostate; QoL=quality of life; Qmax=peak flow rate; PVRU=postvoid residual urine.

Discussion

TURP, the widely used surgical modality for the treatment of patients with BPH, is characterized by less bleeding, greater safety, and immediate success.⁴ Despite multiple developments in minimally invasive therapies for BPH, TURP, which uses monopolar electrosurgical technology, is still considered the best choice for the surgical treatment of symptomatic BPH since it was developed by Nesbit in 1943.¹³ For many years, no significant changes have been made in TURP until the advent of the bipolar resectoscope. Increasingly, studies have shown the advantages of bipolar prostatic resection over monopolar resection, and the principles of this technique have also been well described in some literature reports.^14,15

In the last decade, PKRP has been successfully introduced and widely adopted by urologists.⁷ Numerous clinical studies have shown its safety and efficiency in treating prostates of all sizes with nearly no loss of blood.^7
–9 In this procedure, tissue cutting is ensured by creating a plasma vapor at the loop-tissue interface through a process that is performed at temperatures <70°C and known as molecular dissociation.^7,8 The high energy charged particles produced by this process can cause tissue destruction but at lower temperature. The use of 0.9% sodium chloride solution for irrigation reduces the risk of TUR syndrome, hemolysis, hyponatremia, and glycine intoxication.^8,15 Moreover, the PK resection loop necessitates complete contact with tissue before the beginning of cutting, and the generator features can automatically change for different organizations. Once connected to the prostate capsule, the energy can automatically be reduced. This allows for the avoidance of capsular perforation.^16,17 Consistent with previous studies, our results showed that no capsular perforation was observed in either group and both groups had highly significant improvement in each parameter at the 3-month follow-ups, including IPSS, QOL, Qmax, and PVRU values.

As noted earlier, PKRP appears to be a reliable technique for the management of BPH. PKRP, however, still has the potential risk of causing significant complications and morbidity, especially in patients with larger prostates.^8,12 It is still a difficult and challenging step to resect the tissue near the verumontanum during this procedure. As with the other classic procedures, PKRP involves retrograde movement (from prostate apex toward bladder) of the loop, which controls the verumontanum, allowing it to protect the external urinary sphincter.^13,18 This aspect of the surgery is the main reason for failure. An overly extensive resection may cause damage to the sphincter and an incomplete resection can also result in failure of the procedure. ¹²

The presence of holmium laser enucleation of the prostate (HoLEP) appears to solve many of these problems by enucleating the prostate in an antegrade fashion (from bladder toward the prostate apex).¹⁹ Excellent homeostasis has been proven in this procedure. The holmium laser combined with the transurethral morcellator allows almost bloodless resection of prostatic adenomas of any size.²⁰ The high cost, however, is often presented as a limitation of this technique. Moreover, this technique is a procedure needing substantial expertise in endoscopic surgery and it is difficult to learn.^20
–22

Recently, the presence of a new “mushroom”-style loop permits PKEP with the method just as HoLEP, which provides a new choice for the resection of prostatic adenomas and may be an alternative to HoLEP with a higher cost effectiveness.¹¹ Furthermore, the operative technique of PKEP is similar to PKRP and easy to learn, except for some minor differences.¹² Some studies have reported the feasibility and safety of this technique for the management of BPH, especially in patients with larger prostates.^11,12

We demonstrate the enucleation-resection of whole lobes of the prostate with the technology. During this procedure, the prostatic adenomas were dissected away from the surgical capsule in a retrograde approach from the prostate apex toward the bladder. Because sufficient hemostasis could be easily achieved by the PK system during the operation, clear visibility was provided throughout the process.^7

–10,23 The entire prostate was bluntly exposed and devascularized but still attached to the bladder neck with a narrow pedicle.

Although this process without morcellation may take more time, the whole lobes of the prostate still can be fragmented into pieces very rapidly and bloodlessly using the conventional PK cutting loop, because it is not necessary to change the resection electrode and the irrigation fluid during the following procedures. In addition, there is no risk of cutting through the capsule after cutting a devascularized adenoma. Especially in cases of a large prostate gland, these characteristics allowed the PKEP to speed up the resection time and get much more increases in the resected tissue weight, which particularly benefited high-risk patients by reducing the morbidity of the procedure.^11,12

In our present study, both PKRP and PKEP groups were similar with respect to the resected tissue weight, catheterization time, and total hospital stay. The blood loss observed in the PKEP group, however, was significantly less than in the PKRP group. The number of patients in whom transient incontinence developed at 2 months was fewer in the PKEP group, and this difference was statistically significant. One possible explanation for these results is that the tip of the resectoscope sheath was moved under the adenoma and mechanically dissected the prostatic adenoma away from the surgical capsule during PKEP, just as the surgeon's index finger in open prostatectomy. The prostatic apex was mainly dissected by mechanical operation, which can effectively avoid external sphincter damage coursing by the electrical thermal effect.

As can be seen in our study, both groups had significant improvement from baseline in each parameter at the follow-ups, including IPSS, QOL, Qmax, and PVRU values. These results suggested that the PKEP can be performed safely and with similar efficacy to PKRP.

PKEP, however, is developed on the basis of the open retropubic prostatectomy and PKRP. During this procedure, the anatomic plane must be made until the surgical capsule is reached just as the surgeon's index finger does in open prostatectomy to ensure the complete removal of the prostatic adenoma and reduce the potential complications of postoperative urinary incontinence and intraoperative bleeding.

Based on our experience, the surgeon should have performed more than 50 cases of open retropubic prostatectomy before undertaking PKEP. In addition, PKEP should be avoided in some patients, including those with the following: (1) BPH mainly consisting of fibrosis, which adheres to the surgical capsule and is difficult to separate; (2) prostatic hyperplasia in a patient with a history of prostatitis that was treated with prostatic injection or radiofrequency treatment; and (3) invasive prostate cancers without a clear capsule, which cannot be resected by the retrograde movement of the loop.

Furthermore, although the prostate could theoretically be more easily treated with PKEP, the TUR syndrome is still possible with PKEP but not with open prostatectomy. Especially for large prostates, the operative time is inevitably prolonged. Thus, in patients with a prostate larger than 100 g or a higher risk of congestive heart failure related to cardiopulmonary diseases, open prostatectomy may be a better choice with a much smaller risk of comorbidities.

Conclusions

This initial study shows that PKEP is a safe and effective method for the endoscopic management of BPH. Compared with PKRP, the main advantage of PKEP is a decreased risk of blood loss and transient incontinence. Thus, large prostates could theoretically be more easily dissected and treated with PKEP. This technique, however, brings no advantages in terms of operative time, hospital stay, and voiding function. Although this study is not a randomized trial and results in a low level of evidence, the 3-month follow-up results are still encouraging. Future well-designed, randomized trials with extended follow-up and larger sample size may be needed to better define the role of PKEP in treating patients with symptomatic BPH.

Footnotes

Disclosure Statement

No competing financial interests exist.

Abbreviations Used

References

Bushman

. Etiology, epidemiology and natural history of benign prostatic hyperplasia. Urol Clin North Am, 2009; 36:403–415.

Roehrborn

, McConnell

, Bonilla

et al. Serum prostate specific antigen is a strong predictor of future prostate growth in men with benign prostatic hyperplasia. PROSCAR long-term efficacy and safety study. J Urol, 2000; 163:13–20.

Berry

, Coffey

, Strandberg

, Ewing

. Effect of age, castration, and testosterone replacement on the development and restoration of canine benign prostatic hyperplasia. Prostate, 1986; 9:295–302.

Madersbacher

, Lackner

, Brössner

et al. Reoperation, myocardial infarction and mortality after transurethral and open prostatectomy: A nation-wide, long-term analysis of 23,123 cases. Eur Urol, 2005; 47:499–504.

Rassweiler

, Teber

, Kuntz

, Hofmann

. Complications of transurethral resection of the prostate (TURP)—incidence, management, and prevention. Eur Urol, 2006; 50:969–980.

Mebust

, Holtgrewe

, Cockett

, Peters

. Transurethral prostatectomy: immediate and postoperative complications. A cooperative study of 13 participating institutions evaluating 3,885 patients. 1989. J Urol, 2002; 167:999–1004.

Alschibaja

, May

, Treiber

et al. Recent improvements in transurethral high-frequency electrosurgery of the prostate. BJU Int, 2006; 97:243–246.

Bhansali

, Patankar

, Dobhada

, Khaladkar

. Management of large (>60 g) prostate gland: PlasmaKinetic Superpulse (bipolar) versus conventional (monopolar) transurethral resection of the prostate. J Endourol, 2009; 23:141–145.

Starkman

, Santucci

. Comparison of bipolar transurethral resection of the prostate with standard transurethral prostatectomy: Shorter stay, earlier catheter removal and fewer complications. BJU Int, 2005; 95:69–71.

10.

Yang

, Lin

, Chang

et al.

Gyrus plasmasect: Is it better than monopolar transurethral resection of prostate?

Urol Int, 2004; 73:258–261.

11.

Neill

, Gilling

, Kennett

et al. Randomized trial comparing holmium laser enucleation of prostate with plasmakinetic enucleation of prostate for treatment of benign prostatic hyperplasia. Urology, 2006; 68:1020–1024.

12.

Zhao

, Zeng

, Zhong

et al. A prospective, randomised trial comparing plasmakinetic enucleation to standard transurethral resection of the prostate for symptomatic benign prostatic hyperplasia: Three-year follow-up results. Eur Urol, 2010; 58:752–758.

13.

Nesbit

. Transurethral prostatic resection: A discussion of some principles and problems. J Urol, 1951; 66:362–372.

14.

Tucker

, Kramolowsky

, Bedell

, Platz

. A comparison of urologic application of bipolar versus monopolar five French electrosurgical probes. J Urol, 1989; 141:662–665.

15.

Autorino

, Damiano

, Di Lorenzo

et al. Four-year outcome of a prospective randomised trial comparing bipolar plasmakinetic and monopolar transurethral resection of the prostate. Eur Urol, 2009; 55:922–929.

16.

, Wang

, Huang

. Properties in penetrating capsula of transurethral plasmakinetic resection: Comparison with transurethral resection of the prostate in an ex vivo study. Urol Int, 2009; 82:97–100.

17.

, Tan

, Chew

et al. Comparison of the thermal and histopathological effects of bipolar and monopolar electrosurgical resection of the prostate in a canine model. BJU Int, 2010; 105:1314–1317.

18.

Mazur

, Thompson

. Efficacy and morbidity of “channel” TURP. Urology, 1991; 38:526–528.

19.

Tan

, Gilling

, Kennett

et al.

A randomized trial comparing holmium laser enucleation of the prostate with transurethral resection of the prostate for the treatment of bladder outlet obstruction secondary to benign prostatic hyperplasia in large glands (40 to 200 grams)

J Urol, 2003; 170:1270–1274.

20.

Kuntz

, Ahyai

, Lehrich

, Fayad

. Transurethral holmium laser enucleation of the prostate versus transurethral electrocautery resection of the prostate: A randomized prospective trial in 200 patients. J Urol, 2004; 172:1012–1016.

21.

Naspro

, Suardi

, Salonia

et al. Holmium laser enucleation of the prostate versus open prostatectomy for prostates >70 g: 24-month follow-up. Eur Urol, 2006; 50:563–568.

22.

El-Hakim

, Elhilali

. Holmium laser enucleation of the prostate can be taught: The first learning experience. BJU Int, 2002; 90:863–869.

23.

de Sio

, Autorino

, Quarto

et al. Gyrus bipolar versus standard monopolar transurethral resection of the prostate: A randomized prospective trial. Urology, 2006; 67:69–72.