Thulium Laser Vaporesection Versus Transurethral Electrovaporization of the Prostate in High-Risk Patients with Benign Prostatic Hyperplasia

Abstract

Objective: The purpose of this study was to compare the safety and efficacy of the thulium laser vaporesection and transurethral electrovaporization of the prostate for the treatment of high-risk patients with benign prostatic hyperplasia. Background data: From September 2009 to March 2011, 98 consecutive patients with symptomatic bladder outlet obstruction caused by benign prostatic hyperplasia received either thulium laser vaporesection of the prostate (n=42) or transurethral electrovaporization of the prostate (n=56) at our institution. Materials and methods: Functional follow-up included measurement of International Prostate Symptom Score, quality of life score, maximal urinary flow rate, and post-voiding residual urine volume. All complications were recorded. Results: Thulium laser vaporesection of the prostate was slightly superior to transurethral electrovaporization of the prostate in catheterization time (2.1±0.9 vs. 4.5±1.3 days, p<0.0001) and postoperative hospital stay (4.4±1.8 vs. 6.6±2.0 days, p<0.0001). Within the observation period, both groups had a significant improvement from baseline in subjective or objective success rates; however, no significant difference was found between the two groups. Peri- and postoperative complications were fewer in the thulium laser group. Conclusions: Thulium laser vaporesection of the prostate is as effective as transurethral electrovaporization of the prostate in managing high-risk patients, with sufficient tissue ablation and acceptable hemostasis, and has the advantage of less morbidity and shorter catheter time and postoperative hospital stay.

Introduction

B enign prostatic hyperplasia (BPH) is one of the most common diseases in modern society. The surgical interventions in patients with BPH are in a state of evolution, driven largely by advanced instruments and techniques. Transurethral resection of the prostate (TURP) is still regarded as the gold standard for surgical treatment of BPH.¹ Holmium laser enucleation of prostate (HoLEP) and high-power potassium-titanyl-phosphate (KTP) laser have shown good functional outcomes comparable to TURP.^2
–4 Transurethral electrovaporization of the prostate (TUVP), a modification of existing transurethral technology, is as effective as standard TURP in the treatment of moderate-sized BPH with comparable durability.^5,6

In recent years, thulium: yttrium-aluminium-garnet (Tm:YAG) laser has been proposed as a new technology for vaporization, vaporesection, or enucleation of the prostate.^7

–10 Many clinical trials have been reported comparing Tm:YAG laser prostatectomy with TURP, and TUVP with TURP, but very few have compared laser therapy with TUVP. As BPH frequently occurs in the aging man, such patients also tend to have multiple comorbidities such as coronary heart disease, hypertension, diabetes mellitus, and organ dysfunction. The aim of the present study was to compare the efficacy, safety, and durability of Tm:YAG laser vaporesection of the prostate with that of TUVP in high-risk patients with moderate to severe bladder outlet obstruction caused by BPH.

Materials and Methods

Patients

From September 2009 to March 2011, 98 consecutive patients with symptomatic bladder outlet obstruction caused by BPH were randomly selected into either the Tm:YAG laser vaporesection of the prostate group (n=42) or the TUVP group (n=56) at our institution. All patients provided an informed written consent, and the study was approved by our ethical committee. Inclusion criteria were existence of comorbidities, age <85 years, medical therapy failure, presence of moderate or severe lower urinary tract symptoms (LUTS) (International Prostate Symptom Score [IPSS]>7), maximum urinary flow rate (Q_max)≤15 mL/sec, post-voiding residual urine volume (PVR)≥50 mL, and transrectal ultrasound adenoma volume <80 g. Exclusion criteria were neurogenic bladder, urethral stricture, a diagnosis of prostate cancer, and patient inability to receive anesthesia because of severe disease.

Before the operation, all patients were evaluated with a general and urological examination, including routine blood test and urine analysis, coagulation profile, serum prostate-specific antigen (PSA) level, serum creatinine, serum alanine transaminase, electrocardiogram, echocardiography, lung function test, abdominal ultrasonography, and digital rectal examination. For our patients, voiding symptoms and their influence on quality of life (QoL) were assessed using the IPSS and QoL score, respectively; PVR and Q_max were determined by abdominal ultrasonography and uroflowmeter, respectively. The prostate volume was calculated using the formula: prostate volume=0.52×height×width×length (where height was the anteroposterior diameter, width the maximum transverse diameter, and length the cephalocaudal distance).

High risk patients were defined as patients presenting with various systemic diseases such as coronary heart disease (n=55), hypertension (n=61), pulmonary insufficiency (n=27), diabetes mellitus (n=55), cerebral infarction (n=10), and renal insufficiency (n=9). Furthermore, all patients required special treatment for their systemic diseases. The detailed comorbidities in each group are shown in Table 1. It is worth noticing that many patients had more than one comorbidity.

Table 1.

Baseline Characteristics of Patients Undergoing Tm:YAG Laser Vaporesection of the Prostate or TUVP

Characteristic	Tm:YAG laser group	TUVP group	p Value
No. pts (n)	42	56
Age (y)	69.5±6.6	67.8±6.1	0.209
Prostate volume (mL)	57.7±18.0	55.6±18.4	0.585
PSA (ng/mL)	2.3±1.1	2.3±1.2	0.897
Comorbidities
Coronary heart disease	27	28	0.158
Hypertension	28	33	0.434
Pulmonary insufficiency	14	13	0.267
Diabetes mellitus	26	29	0.318
Cerebral infarction	6	4	0.413
Renal insufficiency	5	4	0.650
ASA Scores			0.088
Class II	23	40
Class III	19	16

Data presented as mean±standard deviation or frequencies. p value of<0.05 was considered statistically significant.

PSA, prostate-specific antigen; Tm:YAG, thulium:yttrium-aluminium-garnet; TUVP, transurethral electrovaporization of the prostate; ASA, American Society of Anesthesiologists.

Preoperative management

Medicine to ameliorate cardiac function was administered to BPH patients with cardiac insufficiency. A temporary or permanent artificial heart driver-extractor was implanted for those with atrioventricular block grade II or more. For patients with primary hypertension, decompression drugs were applied to control blood pressure<140/90 mmHg. Patients with pulmonary insufficiency were given medicine for dilatation of bronchus or expectorant to improve pulmonary function. Application of insulin or oral biguanides for patients with diabetes aimed to decrease empty stomach blood sugar to <8.0 mmol/L. Generally, patients with cerebral infarction received surgery after 6 months of medical treatment. If renal function insufficiency was caused by lower urinary tract obstruction as a result of BPH, a Foley catheter was inserted for 2 weeks to ameliorate renal function. To ensure a safe procedure, preoperative discussion was conducted for every patient before operation and, if necessary, physicians from other departments were also invited.

Tm:YAG laser vaporesection of the prostate

The 2 μm continuous-wave Tm:YAG laser (Revolix, LISA laser products, Katlenburg, Germany) was used at an average power level of 70 W. We performed vaporesection using a 550 μm optical core bare-ended fiber (RigiFib, LISA laser products, Katlenburg, Germany) in combination with a 24 F continuous flow resectoscope (R.Wolf, Knittlingen, Germany). The terminology vaporesection describes simultaneous vaporization and resection of prostate tissue. After laser incisions at the 5 and 7 o'clock lithotomy positions, the median lobe was first vaporesected. With L-shaped movement of the laser fiber, the right lateral lobe was removed stepwise in a retrograde fashion. Then the left lateral lobe was removed using a similar technique in an anterograde fashion. The lateral lobes as well as apex of prostate were vaporesected until the proximity of the surgical prostate capsule was reached. The laser handle was moved quickly to resect the residual tissue and slick the cutting surface of the prostate. By vaporizing and resecting small pieces of prostate, tissue fragments can be easily washed out through the resectoscope sheath without morcellation. All tissue removed from each patient was examined pathologically.

Transurethral electrovaporization of the prostate

A standard continuous flow resectoscope was used for all TUVP procedures, with an electrosurgical generator (Valleylab, CO) providing the power. TUVP was performed using a Vaportrode electrode (Circon, ACMI, Stamford, CT) with setting of 240 W for cutting and 60 W for coagulation. The vaporization technique of the prostate was performed as previously described.¹¹

At the end of each operation, a Foley catheter was inserted into the bladder. Based on prostate size, bladder function, and intraoperative conditions, bladder irrigation was necessitated to help flush out any blood clots in the bladder. The Foley catheter was generally removed when gross hematuria disappeared. Then, after a 24 h observation period, the patient was discharged from the hospital if voiding adequately. Routine blood test, serum creatinine, and electrolytes were also evaluated. To reduce postoperative infection, antibiotic prophylaxis was administered 1 h before the operation, continuing for several days postoperatively (once a day).

Outcome assessment

Detailed information was gathered from the medical records, including patient age, prostate volume, operating time, changes in hemoglobin and serum sodium, catheterization time, and postoperative hospital stay. All complications were recorded, and IPSS, QoL, Q_max, and PVR were also followed and assessed postoperatively in the two groups.

Statistical analysis

Data are presented as mean±standard deviation (SD). Statistical analysis was performed using SPSS-15 for windows (SPSS, SPSS Inc., Chicago, IL). The χ² test was used for categorical variables and the Student t test was used for continuous variables. A value of p<0.05 was considered statistically significant.

Results

Baseline characteristics

Table 1 lists the baseline characteristics of the patients. There was no statistically significant difference in any parameters between the two groups. The mean age of the patients was 69.5±6.6 years (range, 58–80) in the Tm:YAG laser group (42 patients) and 67.8±6.1 years (range, 55–78) in the TUVP group (56 patients).

Perioperative data

The details of perioperative variables are shown in Tables 2 and 3. Both groups had comparable preoperative values for IPSS, QoL, Q_max and PVR. In the Tm:YAG laser group, continuous bladder irrigation was required in 13 patients (31.0%). Tissue samples were available for histological examination through resecting the prostate into small pieces. We noticed a high incidence of coexisting prostatitis in 15 patients and prostatic intraepithelial neoplasia (PIN) 1 in 8. In addition, five BPH patients had both prostatitis and PIN 1. In the TUVP group, 33 patients (58.9%) required bladder irrigation temporarily, and the other 23 (41.1%) did not. Catheter time and hospital stay were significantly shorter in the Tm:YAG laser group than in the TUVP group (p<0.05).

Table 2.

Perioperative Characteristics of the Patients in the Two Groups

Characteristic	Tm:YAG laser group	TUVP group	p Value
No. of pts (n)	42	56
Operating time (min)	66.8±12.9	61.8±12.4	0.055
Serum sodium (mmol/L)
Preoperatively	140.0±2.7	139.3±3.1	0.245
Postoperatively	138.9±2.6	138.2±3.2	0.265
Serum hemoglobin (g/L)
Preoperatively	141.6±13.1	143.0±12.9	0.604
Postoperatively	138.6±11.8	133.1±16.3	0.070
Catheterization time (da)	2.1±0.9	4.5±1.3	0.000
Hospital stay (da)	4.4±1.8	6.6±2.0	0.000

Data presented as mean±standard deviation. p value of<0.05 was considered statistically significant.

Tm:YAG, thulium:yttrium-aluminium-garnet; TUVP, transurethral electrovaporization of the prostate.

Table 3.

Efficacy Parameters of the Patients During 1 Year Follow-Up

		Postop (month)
Parameter	Preop	1	3	12
Tm:YAG laser pts (n)	42	42	41	36
IPSS	21.5±5.9	7.7±1.9	6.7±1.7	3.6±1.3
QoL	4.8±0.9	1.6±0.6	1.2±0.4	0.9±0.6
Q_max (mL/sec)	7.8±2.3	16.6±4.6	17.8±5.0	23.2±6.6
PVR (mL)	96.0±26.4	41.0±13.2	27.6±8.3	25.6±8.6
TUVP pts (n)	56	56	54	52
IPSS	21.0±6.1	8.0±2.3	6.9±2.3	3.7±1.8
QoL	4.6±0.9	1.8±0.5	1.3±0.5	1.0±0.7
Q_max (mL/sec)	8.1±2.6	15.3±5.1.	17.7±5.8	22.8±7.2
PVR (mL)	89.5±21.0	42.8±10.5	27.7±7.3	26.4±6.9

Data presented as mean±standard deviation. In comparison with baseline, there was statistically significant improvement in all efficacy parameters in each group (p<0.05).

Tm:YAG, thulium:yttrium-aluminium-garnet; TUVP, transurethral electrovaporization of the prostate; IPSS, International Prostate Symptom Score; PVR, post-voiding residual urine volume; QoL, quality of life score; Q_max, maximum urinary flow rate.

Follow-up

Within the observation period, one patient in the Tm:YAG laser group died of causes unrelated to the procedure (cerebral infarction). Seven patients were lost to follow-up, and three patients were unwilling to participate in the follow-up (six in the Tm:YAG laser group; 4 in the TUVP group). In comparison with baseline, there was statistically significant improvement in all efficacy variables at postoperative assessment in each group (Table 3). One year after the operation, the mean IPSS improved by 83.3% in the Tm:YAG laser group and by 82.4% in the TUVP group. Q_max improved approximately threefold in each group. In the meantime, PVR volume decreased by 73.3% in the Tm:YAG laser group and by 70.5% in the TUVP group. However, no clinical or statistically significant difference was found between the two groups in subjective or objective success rates.

Complications

Table 4 lists adverse events, which were reported using the modified Clavien Classification of Surgical Complications.^12,13 No intraoperative complications occurred. Postoperatively, one patient in the Tm:YAG laser group received a blood transfusion (grade II) because of low hemoglobin, whereas three patients in the TUVP group required a blood transfusion. After catheter removal, urinary retention occurred in two patients in the Tm:YAG laser group and in three patients in the TUVP group, necessitating recatheterization (grade I) during the hospital stay. Ten patients experienced urinary tract infection (grade II), which responded well to antibiotic treatment. There were statistically significant differences of irritative symptoms between the two groups (p<0.05). All patients (5 in the Tm:YAG laser and 16 in the TUVP groups) who complained of irritative symptoms (grade I) had these symptoms resolve without medical intervention.

Table 4.

Intra- and Postoperative Complications in the Two Groups

Complications	Tm:YAG laser group	TUVP group	p Value
No. of pts (n)	42	56
Perioperative
Blood transfusion (grade II)	1(2.4)	3(5.4)	0.825
Recatheterization (grade I)	2(4.8)	3(5.4)	1.000
Urinary tract infection (grade II)	4(9.5)	6(10.7)	1.000
Irritative symptom (grade I)	5(11.9)	16(28.6)	0.047
Follow-up
Urethral stricture (grade IIIb)	—	4(7.1)	0.210
Bladder neck contracture (grade IIIb)	1(2.4)	1(1.8)	1.000

Data presented as frequencies and percentage. p value of<0.05 was considered statistically significant.

Tm:YAG, thulium:yttrium-aluminium-garnet; TUVP, transurethral electrovaporization of the prostate.

During the follow-up period, no patients in the Tm:YAG laser group developed urethral stricture (grade IIIb), whereas four with TUVP did. Bladder neck contracture (grade IIIb) was observed in one patient in each group. All bladder neck contractures and urethral strictures required precise incision with the Tm:YAG laser. In our study, patients remained free of complications such as urinary incontinence and transurethral resection syndrome.

Discussion

According to the American Urological Association's Guideline, TURP remains as the gold standard for surgical treatment of patients with moderate to severe LUTS caused by BPH.¹⁴ TUVP is a modification of existing transurethral technology, and several clinical studies have demonstrated significant improvements in both symptoms and flow rates, with similar repeat operation rates and long-term complication rates.⁵ Moreover, the advantages of TUVP are that the urethral catheter is withdrawn earlier, hospitalization is shorter, and bleeding is less. Therefore, TUVP should be preferred in elderly patients in whom there is no suspicion of prostate cancer and for whom bleeding during operation would be a source of risk.¹⁵ In an attempt to achieve tissue vaporization with bipolar high-frequency generators, plasma vaporization of the prostate, a current development of TUVP, has been clinically introduced. Despite a small nonrandomized study cohort with limited follow-up, Reich et al. demonstrated the safety and efficacy of bipolar plasma vaporization for patients with LUTS in their initial experience.¹⁶

Preliminary results have indicated that vaporesection of the prostate using the 2 μm continuous-wave laser is safe and efficient.^{17, 18} In our study, operating time for the Tm:YAG laser group was slightly longer than for the TUVP group. However, the mean operating time for Tm:YAG laser prostatectomy was consistent with previous studies.^{8,10,17

–20} With extensive endoscopic experience and proper training, the surgeon could complete most procedure in <60 min. Considering that prostate volume is positively associated with operating time, Tm:YAG laser prostatectomy is more suitable for small to medium-sized prostate glands.

In view of the excellent hemostatic characteristics of Tm:YAG laser, we currently remove the catheters within 3 days after initial operation. However, in the TUVP group, most patients had indwelling Foley catheters for a duration of 4–5 days. In our experience, early catheter removal is often related to shortened hospitalization. Consequently, the average hospital stay was longer in the TUVP group. We accept the fact that the length of postoperative hospital stay is not consistent with the minimally invasive procedure. In China, most patients do not leave the hospital until they feel that they can return to normal activities, and, therefore, a longer hospital stay was reported in the present series.

In the follow-up, Tm:YAG laser vaporesection of the prostate had good functional results comparable to those of TUVP. We observed a highly significant improvement in each parameter at all intervals in both groups. However, no significant difference was found between the two groups in IPSS, QoL, Q_max, or PVR at any time. Our results confirmed that the Tm:YAG laser prostatectomy was also effective for managing high-risk BPH patients, with similar effects to those of TUVP. The peri- and postoperative complications were less frequent in the Tm:YAG laser group. Because of the characteristic wavelength, the Tm:YAG laser is excellent for controlling bleeding intraoperatively.

Because this was a retrospective and nonrandomized study at a single institution, our study had inevitable limitations. Abdel-Khalek and colleagues compared the safety, efficacy, and durability of neodymium (Nd):YAG laser prostatectomy with TUVP for treating BPH. They found that TUVP was significantly more effective and durable than the Nd:YAG laser for treating BPH.²¹ Of note is that our study only includes high-risk BPH patients with comorbidities. We are currently performing a randomized prospective trial to compare thulium laser prostatectomy with TUVP for the management of BPH patients.

Conclusions

Tm:YAG laser vaporesection of the prostate is as effective as TUVP in managing high-risk patients with BPH, with sufficient tissue ablation and acceptable hemostasis, and has the advantage of less morbidity and shorter catheter time and postoperative hospital stay. Prospective, comparative, larger-scale studies with longer regular follow-up are needed to confirm the durability of these promising outcomes.

Footnotes

Acknowledgments

This work was supported by The National Natural Science Foundation of China (No. 81072098), Science and Technology Commission of Shanghai Municipality (No. 10DZ2270600), Shanghai Leading Academic Discipline Project (No. S30201) and Shanghai Basic Research Project (No. 09DJ1400400).

Author Disclosure Statement

No competing financial interests exist.

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