The RevoLix ™ 2 μm Continuous Wave Laser Vaporesection for the Treatment of Benign Prostatic Hyperplasia: Five-Year Follow-Up

Abstract

Objective: The purpose of this study was to evaluate the long-term efficacy and safety of laser vaporesection using the RevoLix^™ 70 W 2 μm continuous wave (CW) laser in the treatment of benign prostatic hyperplasia (BPH). Background data: From January 2008 to December 2008, 162 patients with BPH underwent vaporesection using 2 μm CW laser. Materials and methods: The International Prostate Symptom Score (IPSS), quality of life (QoL), urinary flow rate (Q_max), post-voiding residual urine volume (PVR), and postoperative complications were observed at baseline and were followed at 3-, 6-, and 12-month intervals (range: 3–60 months). Results: A total of 146 patients completed the 5-year follow-up. At 60 months postoperatively, the mean Q_max increased from 7.5 to 21.2 mL/sec, the mean PVR decreased from 94.3 to 9.4 mL, the mean IPSS score decreased from 20.4 to 6.6, and the mean QoL score decreased from 4.7 to 1.9. Complications included urinary tract infection (3.4%), urethral stricture rate (2.7%), and recurrent bladder outlet obstruction rate (2.1%). Overall, the reoperation rate was 3.4%, and no transurethral resection (TUR) syndrome or blood transfusion was reported. Conclusions: The 2 μm CW laser is a safe and effective option for the treatment of BPH. At the 5-year follow-up, the long-term clinical efficacy and safety are excellent, with low incidence of complications.

Introduction

Benign prostatic hyperplasia (BPH) is a common problem in aging men. Transurethral resection of prostate (TURP) is generally considered the gold standard for surgical treatment of BPH, but the morbidity and complications from TURP are still rather high.^1,2

Various laser devices have been introduced as an alternative treatment option to minimize the operative and postoperative complications of conventional TURP.^3,4 The RevoLix^™ 2 μm continuous wave (CW) laser is considered to be safe with good hemostasis and no damage to surrounding structures.⁵ We evaluated the long-term effectiveness and safety of this device in the treatment of BPH at our institution.

Materials and Methods

Patients

From January 2008 to December 2008,162 BPH patients underwent 2 μm CW laser prostatectomy. Preoperative evaluation included history, physical examination, the International Prostate Symptom Score (IPSS), quality of life (QoL) score, peak urinary flow rate (Q_max), post-void residual urine volume (PVR), prostate size, and appearance on transrectal ultrasonography (TRUS). Laboratory studies included complete blood count with coagulation variables, serum biochemistry, prostate-specific antigen (PSA), and urine culture. Assessed outcomes included operating time, changes in hemoglobin and serum sodium, transfusion rate, and indwelling catheter time. Improvements in Q_max, PVR, IPSS, and QoL outcomes were measured postoperatively at 3 and 6 months, 1 year, and annually thereafter up to 5 years.

Laser system

The 2 μm continuouswave thulium laser (RevoLix) was used for prostate vaporesection at a power level of 70 W. A 550 μm core bare-ended fiber (RigiFib^™, LISA Laser Products) was used combined with a 26 F continuous flow laser resectoscope. Laser treatment of BPH was performed in 0.9% normal saline at room temperature.

Operating technique

The patients received either spinal anesthesia or general anesthesia.

The procedure was performed under direct vision, using the bare-ended laser fiber in contact mode. The degree of vaporization was controlled by the speed of the laser fiber movement through the tissue. At the beginning of the operation, the distal resection border close to the verumontanum was marked, and laser incisions were performed at the 5 and 7 o'clock positions, and continued toward the previously marked resection border. Following this, the median lobe if present was vaporesected first. The lateral lobes and the apical portion of the prostate were then resected systematically until the prostatic capsule was reached. Vaporesection was used to vaporize or resect small pieces of prostate; these tissue chips were small enough to allow easy evacuation through the resectoscope sheath. A Foley catheter was placed at the end of the operation. Ciprofloxacin (200 mg, twice a day) was administered preoperatively, and continued for 3 days postoperatively.

Results

Of the 162 patients, 146 (90%) completed the 5-year follow-up. Of the 16 patients lost to follow-up, 6 died of diseases unrelated to 2 μm CW laser prostatectomy and 10 patients defaulted on their clinical appointments and could not be contacted. The mean age of patients was 73.3 ± 6.4 years. Mean prostatic volume was 72.3 ± 32.4 mL. The preoperative mean PSA was 3.3 ± 1.2 ng/mL. The preoperative characteristics and demographics of the patients are summarized in Table 1.

Table 1.

Patient Characteristics and Demographics

Ages (years)	73.3 ± 6.4
Prostate size (mL)	72.3 ± 32.4
Transurethral or suprapubic catheter	42 (28.8%)
PSA (ng/mL)	3.3 ± 1.2

PSA, prostate-specific antigen.

All patients tolerated the procedure without incident. Mean operative time was 83.4 ± 18.3 min (range, 30–120 min). There were no complications during the procedure, and no blood transfusions were required. Mean catheterization time was 2.8 ± 0.7 days. Pre- and postoperative outcomes are presented in Table 2.

Table 2.

Preoperative and Postoperative Assessments of Patients

		Follow-up (months)
Parameter	Preoperative	3	6	12	24	36	48	60
Q_max (mL/sec)	7.5 ± 3.6	19.6 ± 4.2^*	20.3 ± 4.3^*	22.3 ± 4.9^*	22.1 ± 4.8^*	21.7 ± 5.1^*	21.6 ± 4.7^*	21.2 ± 4.7^*
PVR (mL)	94.3 ± 22.6	16.5 ± 6.3^*	12.6 ± 4.7^*	8.4 ± 3.3^*	7.9 ± 4.2^*	9.1 ± 4.8^*	9.3 ± 5.2^*	9.4 ± 4.5^*
IPSS	20.4 ± 11.3	7.4 ± 3.2^*	6.4 ± 3.3^*	5.3 ± 2.7^*	5.5 ± 3.1^*	6.1 ± 4.2^*	6.3 ± 3.7^*	6.6 ± 3.4^*
QoL	4.7 ± 1.1	2.1 ± 1.1^*	1.8 ± 0.9^*	1.7 ± 0.6^*	1.7 ± 1.1^*	1.8 ± 0.8^*	1.7 ± 1.2^*	1.9 ± 0.7^*

p < 0.01,compared with the perioperative assessment.

Q_max, peak flow rate; PVR, postvoid residual; IPSS, International Prostate Symptom Score; QoL, quality of life.

There were few postoperative complications, as summarized in Table 3.

Table 3.

Complications After Operation

Type of complication	Case (%)
Transient hematuria	24(16.4)
Urinary tract infection	5(3.4)
Blood transfusion	0(0)
TUR syndrome	0(0)
Urethral stricture	4(2.7)
Permanent urinary incontinence	0(0)
Recurrent bladder outlet obstruction	3(2.1)
Reoperation	5(3.4)

TUR, transurethral resection.

Discussion

BPH is a common disorder in men >50 years of age. Although TURP has been considered the ‘‘gold standard’’ for prostate resection, the complication rate is rather high,^1,2 including hemorrhage requiring blood transfusion and the risk of dilutional hyponatremia (transurethral resection syndrome). The wavelength of the 2 μm CW is 2013 nm, which is close to the absorption peak of water. Although it targets the chromophores of water like the Holmium laser, it differs in the emission as a CW laser and not as a pulsed laser like the Holmium. This type of laser emission allows vaporesection of the prostate. It allows simultaneous vaporization and resection of the prostate with good hemostasis and without damaging the surrounding structures. We have previously reported the safety and efficiency of the 2 μm CW laser vaporesection of the prostate in a recent article.⁶

Long-term outcomes using the RevoLix thulium laser system for the treatment of BPH are lacking. In our study, the outcomes showed significant and sustained improvements at each clinic follow-up visit. At 60 months postoperatively, the mean Q_max increased from 7.5 to 21.2 mL/sec, the mean PVR decreased from 94.3 to 9.4 mL, the mean IPSS decreased from 20.4 to 6.6, and the mean QoL decreased from 4.7 to 1.9. The improvements in all clinical parameters are comparable to those produced by TURP.⁷

The TUR syndrome is a serious complication of TURP. Wang reported that the incidences of TUR syndrome ranged from 1% to 12% in monopolar TURP groups.⁸ The 2 μm CW laser minimizes the risk of TUR syndromes in two ways: (1) its penetration depth at the tissue surface level is shallow and quick, and (2) physiologic saline is used as irrigation fluid. In our study, we reported no TUR syndrome, which makes it a safer option especially in longer operative cases. Bleeding is a common complication of TURP. Severe hemorrhages require blood transfusion or can lead to shock-related complications. Fagerstrom et al. reported the incidence of blood transfusion at 4% in the plasmakinetic resection of the prostate (PKRP) group and 11% in the monopolar TURP group.⁹ Hu et al. also reported a blood transfusion rate of 2.7% for PKRP.¹⁰ Comparatively, the blood transfusion rate occurred in 1% and 0.4% for Holmium laser enucleation of the prostate (HoLEP) and potassium titanyl phosphate (KTP) respectively.^11,12 The 2 μm CW laser achieves good hemostasis and it is equally hemostatic as the KTP laser.¹³ Coagulation of blood vessels is easily achieved by defocusing the laser beam. The tissue left behind after each laser pass is covered by a coagulated seam of tissue, which provides hemostasis and provides a clear view of the surgical site. We reported no blood transfusion in our patient cohort.

Urethral stricture is a late complication of prostate surgery. It is the result of mechanical damage, electrical injury, and/or catheterization. The 2 μm CW laser can avoid electrical injury, lessening the time of postoperative catheterization. This can help minimize the risk of urethral stricture formation. In some recent studies, the urethral stricture rate of monopolar TURP was 6.6%,¹⁴ and the rate of PKRP was 5.4%.¹⁰ The rates of HoLEP and KTP were 2.6% and 4.4%, respectively.^12,15 In our study, the incidence of urethral stricture was 2.7% (4/146). Urethral stricture in three patients occured in the urethral orifice, and in one patient it occurred in the anterior urethra. Two patients were treated with urethral dilation and two patients received urethroplasty.

The rate of bladder outlet obstruction recurrence was 2.1% in our patients. They all received reoperation. It is reported that the recurrent bladder outlet obstruction incidence of TURP was 2.1–4.4%.^10,16 The rates of HoLEP and KTP were 1.6% and 3.6%, respectively.^12,15 The reasons included incomplete resection of the prostate gland and the natural course of the disease. The 2 μm CW laser has the ability to precisely incise and excise prostate tissue without uncontrolled tissue damage, to reach “anatomic resection.”

A total of five (3.4%) patients needed reoperation during the 5 years of follow-up. Two patients who had urethral stricture received urethroplasty, and three patients who had recurrent bladder outlet obstruction had repeat 2 μm CW laser vaporesection. In other studies with long-term follow-up, the reoperation rate for TURP was 4.5–13%,^10,17,18 the rate for HoLEP was 4.2%,¹⁹ and the rate for KTP was 6.8%.¹³ The low incidence of late complications demonstrates the long-term safety of the 2 μm CW laser.

The limitation to our study included its retrospective nature, and as such, we can only compare our results with those already published in the literature. This may affect the accuracy of our study, and we encourage more randomized controlled studies in order to validate our findings.

Conclusions

In our long-term study of 5 years, we report excellent clinical outcomes and a low incidence of perioperative and late complications using the 2 μm CW laser for the treatment of BPH.

Footnotes

Author Disclosure Statement

No competing financial interests exist.

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