Vaporesection

Xia et al. reported their initial experience with the Tm:YAG laser on 30 patients using the so‐called “tangerine technique” for BPH treatment [10]. They sliced the prostate in tangerine‐like pieces in situ and extracted these mechanically with a syringe. The ability of the Tm:YAG laser to cut prostate tissue chips small enough for the resectoscope sheath was an important difference from the previously introduced lasers, especially the holmium:YAG (Ho:YAG) laser, which cannot cut or resect. This is the most important difference between thulium and holmium lasers, since the application and surgical techniques of thulium lasers in BPH treatment are very similar to those of holmium lasers.

The patients in this first paper by Xia et al. had a mean prostate volume of 58 ml, an average International Prostate Symptom Score (IPSS) of 19, and a maximum urinary flow rate (Q_max) of 8.0 ml/s [10]. The Tm:YAG laser was used at 50 W. During a mean operating time of 56 minutes, an average of 1 g tissue was removed per minute. This tissue retrieval rate was in the range of contemporary holmium laser enucleation of the prostate (HoLEP) series of that time, which reported enucleation rates of up to 0.71 g/min [11]. In the first series by Xia et al., neither perioperative blood transfusions nor postoperative bladder irrigation were necessary [10]. The Foley catheter remained in situ for 1–3 days. Three months after surgery, Q_max (24.7 ml/s) and IPSS (7.1) had improved significantly. No cases of new onset of impotence were found. These data were confirmed at 1‐year follow‐up [12].

In 2007 Bach et al. reported their initial results with 54 patients being treated with 70 W Tm:YAG high‐power vaporesection of the prostate (mean volume 30.3 ml) and the subsequent 1‐year follow‐up [13]. At that time, holmium laser enucleation of the prostate had already been described [14]. However, one disadvantage of the enucleation procedure was the difficulty in removing the tissue from the bladder: either a mechanical tissue morcellator was used for removal of the enucleated lobes off the bladder or the so‐called “mushroom technique” [15]. In the latter, the prostate is left attached by a pedicle at the bladder neck and the tissue is then resected with a monopolar or bipolar loop into transurethral resection of the prostate (TURP)‐like chips. Vaporesection is a protocol where small chips are produced with a Tm:YAG laser and washed out with a syringe, similar to the standard resection technique. In the series of Bach et al., mean preoperative Q_max was 8.1 ml/s after exclusion of 14 patients with acute urinary retention (AUR). In this first study, removal at a resection speed of 0.6 g/min was achieved, which increased with growing experience to 1.5 g/min. Mean catheter time was 1.7 days (range 1–3 days). Blood transfusions were not required in any patient. However, six patients had urinary tract infections (UTIs) with irritative voiding symptoms 1–2 weeks postoperatively, which required antibiotic therapy. At 1‐year follow‐up, no bladder neck stricture or urethral stenosis had occurred. IPSS, Q_max, postvoid residual urine (PVR), and quality of life (QOL) had improved significantly at 1‐year follow‐up and continued to do so at 18 months follow‐up [13, 16].

After these reports from clinical practice, a systematic ex vivo evaluation of the thulium laser was performed by Wendt‐Nordahl et al. [17]. The ablation capacity and hemostatic properties were tested at different power settings in a previous well‐established model of the isolated blood‐perfused porcine kidney. Histologic examination of the ablated tissue was used to compare changes after thulium laser treatment with results after TURP and use of a 80 W potassium titanyl phosphate (KTP) laser. At a power setting of 70 W, the thulium laser achieved a higher tissue ablation rate (average 6.56 g in 10 minutes). This is, of course, far more than is achieved in clinical practice, since no time is lost for surgical orientation. The KTP laser ablated 3.99 g of tissue in the same time, whereas with TURP 8.28 g was removed in 30 seconds. The bleeding rates were 0.16, 0.21, and 20.14 g/min, respectively. The corresponding depths of the coagulation zones were 264, 666.9, and 287 µm, respectively. In conclusion, this study showed that the thulium laser offered a higher tissue ablation capacity and similar hemostatic properties to the KTP laser, and in comparison to TURP the bleeding rate was significantly reduced. The smaller quantity of removed tissue compared to TURP was due to the fact that the thulium laser was used for vaporization only.

The first prospective randomized prospective trial was performed by Xia et al. [18]. One hundred patients were randomized into two groups: 52 underwent Tm:YAG laser resection using the tangerine technique mentioned above and 48 underwent standard TURP. Preoperative assessment included IPSS, QOL, Q_max, PVR, International Index of Erectile Function‐5 (IIEF‐5), and urodynamic studies. Those parameters were re‐evaluated at 1, 6, and 12 months. Catheterization time was significantly shorter in the laser group (45.7 vs. 84 hours; P < 0.0001). Blood loss was less in the laser group and hemoglobin was lower (0.92 vs. 1.46 g/ml; P < 0.001) than in the TURP group. IPSS, QoL, Qmax, PVR and IIEF‐5 as well as urodynamic studies did not reveal any significant difference between the groups. Both groups benefitted from the respective interventions.

Results from a larger series of patients (n = 200), also with larger prostate sizes (up to 120 g), were published by Mattioli et al. [19]. They used a 70 W laser with bare‐ended and side‐firing laser fibers. Bare‐ended fibers used with the cw thulium laser are applicable for all BPH protocols, such as vaporization, vaporesection, and vapoenucleation; however, side‐firing fibers are used for vaporization only. Mattioli et al. advocated the use of both fibers. They used a laser that enabled switching with a foot pedal between the two modes, and preferred to resect first and vaporize thereafter. In patients with prostates smaller than 35 g, vaporization was performed; in those with prostates larger than 35 g vaporesection and/or vaporization was performed. Mean catheterization time was 16 hours (range 12–72 hours). The efficacy of the procedures was evaluated with Q_max, PVR, and the IPSS questionnaire. The authors concluded that clinical outcome was comparable with TURP and the KTP and Ho:YAG lasers.

Szlauer et al. have published a DVD on the vaporesection procedure with a thulium laser [20]. This DVD shows the main steps of the technique as introduced by Bach et al. [13]. The laser fiber is moved semi‐circumferentially from the verumontanum towards the bladder neck, thereby undermining tissue and cutting chips. Szlauer et al. reported the results from 56 nonconsecutive patients. The mean procedure time was 60 minutes, postoperative irrigation was necessary in 19 of 56 patients (29%), and the mean time of catheterization was 23 hours. The decrease of hemoglobin was at 0.2 mg/ml until the day of discharge. Mean Q_max improved from 8.1 to 19.3 ml/s (P < 0.001) and the PVR decreased from 152 to 57 ml (P < 0.05). This study included the first report of the need for blood transfusions (two patients, 3.6%) after thulium laser procedures. Two patients needed recatheterization postoperatively. After a mean follow‐up of nine months, IPSS improved from 19.8 at baseline to 8.6 (P < 0.001). During the learning curve, persisting obstructive symptoms in four patients necessitated a second procedure. Szlauer et al. chose TURP, while a few other authors have reported satisfactory second procedures for persisting complaints utilizing the Tm:YAG laser in a resection technique [21]. During the learning curve for a new technique, such as any laser procedure, it is appropriate to fall back on the standard procedure. Two patients in this series developed postoperative complications (one urethral stricture and one bladder neck contracture).

Over time, vaporesection has become less important as there is a strong trend towards enucleation techniques – no matter what energy source is used. But vaporesection still has its uses in thulium laser treatment of the prostate as it is an important step during the learning curve from vaporization to complete enucleation.

Vapoenucleation

Following their work on vaporesection with thulium lasers, Bach et al. looked at holmium laser enucleation and implemented thulium lasers for this technique (so‐called vapoenucleation of the prostate) in 2009 [21]. This represented a development because vaporesection and, indeed, any kind of pure vaporization, was limited to smaller glands, as the amount of tissue that can be removed by vaporization techniques is time limited, necessitating prolonged operating times with increasing prostate volumes. It became obvious that for larger glands tissue removal using mechanical morcellators must be an integral part of the procedure. Bach et al. again used a 70 W laser to remove the tissue, as in the previously described three‐lobe technique in HoLEP [22], in 88 patients with a mean prostate size of 61.3 g. In brief, the procedure starts with the marking of the distal resection border close to the verumontanum. Turner–Warwick‐like incisions down to the surgical capsule are made at the 5 and 7 o’clock positions up to the previously marked distal resection border. Then the entire median lobe of the prostate is enucleated. After that, the first lateral lobe and consequently the second lateral lobe are enucleated and positioned into the bladder for morcellation. After enucleation, tissue is morcellated within the bladder [22].

In 2015, Kim et al. published a variation of enucleation, the “all‐in‐one” technique [23]. The mean operative time was 82.1 ± 33.3 minutes and the mean enucleation and morcellation times 52.7 ± 21.7 minutes and 8.2 ± 7.0 minutes, respectively. The mean resected tissue weight and decrease in hemoglobin were 36.9 ± 24.6 g and 0.4 ± 0.8 g/dl, respectively. These results are consistent with two‐ or three‐lobe techniques [23].

Bach et al. demonstrated the feasibility of laser enucleation of the prostate using the thulium laser, as previously shown for Ho:YAG lasers [21]. The authors discussed the advantages of this laser in comparison with open simple prostatectomy and Ho:YAG laser enucleation [21]. The operative time was 72 minutes, of which laser time (beam on) was 32.4 minutes. The remainder of the operative time, as in any other transurethral procedure, was taken up by instrumentation, catheterization, and morcellation. According to the authors, a suprapubic trocar could be used to perform a low‐pressure procedure. An average of 127 kJ of laser energy was applied. An average of 31.7 g of prostatic tissue was available for histologic examination. The percentage of tissue lost through vaporization was estimated to be 30%, and it should be noted that the amount of retrieved tissue is often underestimated because of this. The average Foley catheter time was the same as in other laser procedures, being 2.1 days. Three patients (4.2%) had persistently high residual urine after removal of the Foley catheter and were discharged with suprapubic catheter in situ. At 1‐year follow‐up, improvements in urodynamic parameters appeared to be durable, with an increase in Q_max from 3.5 to 23.3 ml/s (P < 0.001) and decrease in PVR from 121 to 33 ml. IPSS decreased from 18.4 to 6.8. Early complications were UTI in 6.8%, hematuria in 5.6%, and the need for immediate retreatment in 2.2%. One patient developed an urethral stricture. Postoperative dysuria was reported in 27%, a rate similar to that with any other ablative procedure in the prostate [24]. At 48‐month follow‐up, Q_max, PVR, IPSS, and QOL were still significantly better compared with baseline (P < 0.001). Bladder neck contractures and urethral strictures developed during follow‐up in 1.6% and 0.8% of the patients, respectively. No patient had to be retreated during follow‐up for recurrent prostatic tissue [25].

A slight variation of thulium vapoenucleation of the prostate (ThuVEP) is called thulium laser enucleation of the prostate (ThuLEP). ThuLEP is blunt transurethral anatomical enucleation of the prostate using the beak of the resectoscope with Tm:YAG laser support [26]. A large series with 1080 patients treated with ThuVEP confirmed the previously published data; median prostate size was 51 ml and median operation time was 56 minutes. Median enucleation time in this group was 32.5 minutes. Median resected tissue weight was 30 g, confirming that 60% of tissue should be resected. Incidental carcinomas were detected in 5.5% of the patients. Q_max (8.9 vs. 18.4 ml/s) and PVR improved significantly at discharge (P < 0.001). Clavien 1 and 2 complications occurred in 24.6% and Clavien 3 in 6.6%. There was only one Clavien 4 complication (0.09%). The overall complication rates decreased significantly over time with increasing individual and institutional experience of the ThuVEP procedure [27].

Open prostatectomy has been considered the standard technique for larger glands. It is effective and durable, but the rate of severe complictions is high. In one of the last large series of open prostatectomy, Serretta et al. in 2002 reported a complication rate of 15% [28]. Although the average overall complication rates for open prostatectomy and Tm:YAG laser prostatectomy appear to be comparable, the rates of severe unexpected complications, bleeding‐related complications, and transfusion drop significantly with Tm:YAG laser prostatectomy. This is particularly important because surgical treatment for BPH tends to be performed in an older age group. Transfusion rates of 8.2–26.5% have been reported with open prostatectomy [29]

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