A comparative study of thulium laser resection of the prostate and bipolar transurethral plasmakinetic prostatectomy for treating benign prostatic hyperplasia
Correspondence: Jun-hua Zheng, Department of Urology, Shanghai Tenth People's Hospital of Tangji University, No. 301 Yanchang Road, Shanghai 200072. P. R. China.
What's known on the subject? and What does the study add?
- Thulium laser is a new generation of surgical laser. It is a minimally invasive technology with several advantages, including rapid vaporization and minimal tissue damage and bleeding. However, details regarding the safety and efficacy of thulium laser in treating BPH remains unknown.
- We performed a comparative study in 100 patients with BPH of the safety and efficacy of thulium laser resection of the prostate (TMLRP, n = 50) and bipolar transurethral plasmakinetic prostatectomy (TUPKP, n = 50). We found that the efficacy and indications were the same in TMLRP and TUPKP. In TUPKP, the morbidity of urethrostenosis was low, and was nearly bloodless in surgery and had higher safety. Nevertheless, TUPKP is more suitable for patients with larger prostate volume.
- To compare the safety and short-term efficacy of thulium laser resection of the prostate (TMLRP) and bipolar transurethral plasmakinetic prostatectomy (TUPKP) for the treatment of patients with benign prostatic hyperplasia (BPH).
- A total of l00 patients diagnosed with BPH were randomly divided into two groups, treated with either TMLRP (50, group 1) or TUPKP (50, group 2).
- There was no significant difference in preoperative variables such as age, prostate volume, prostate-specific antigen (PSA) level, International Prostate Symptom Score (IPSS), maximum urinary flow rate (Qmax) and postvoid residual urine volume (PVR) between the two groups.
- The perioperative parameters and therapeutic effects were recorded and compared between the two groups.
- There were significant differences in the following parameters between the two groups (TMLRP vs TUPKP [mean ± SD]): operation duration, 61.2 ± 24.2 vs 30.14 ± 15.9 min; catheterization time, 1.8 ± 0.4 vs 3.2 ± 0.6 d; postoperative hospital stay, 3.3 ± 0.8 vs 4.1 ± 1.3 d.
- The volume of blood loss and postoperative bladder irrigation were significantly lower in TMLRP group than in the TUPKP group.
- At 1 month after the operation, there were four cases of urethral stricture in the TUPKP group.
- At 3 months after the operation, IPSS, quality of life (QoL), Qmax and PVR were significantly improved, with no significant difference between the two groups.
- TMLRP is superior to TUPKP in terms of safety, blood loss, recovery time and complication rate, and is as efficacious as TUPKP for treating BPH.
- Operation duration was significantly longer in the TMLRP group than in the TUPKP group.
postvoid residual urine volume
quality of life
thulium laser resection of the prostate
transurethral plasmakinetic prostatectomy
Thulium laser is a new generation of surgical laser. It is a minimally invasive technology with several advantages, including rapid vaporization and minimal tissue damage and bleeding. For further investigation of the efficacy of thulium laser in treating BPH, we performed a comparative study of the safety and efficacy of the surgery. From November 2009 to August 2010, we treated 100 patients with BPH with thulium laser resection of the prostate (TMLRP) or bipolar transurethral plasmakinetic prostatectomy (TUPKP) (n = 50 for each surgical treatment).
Patients and Methods
A total of 100 symptomatic BPH patients were included in the present study. All patients were evaluated with DRE, TRUS, IPSS, quality of life (QoL) score, urodynamic assessment and PSA level, and given clear diagnoses. There were four cases of renal insufficiency, 37 cases of hypertension, 24 cases of coronary heart disease, 13 cases of diabetes and seven cases of moderate to severe ventilation dysfunction.
Patients were randomized into two groups: 50 in the TMLRP group and 50 in the TUPKP group. The patient characteristics (mean ± SD) were as follows (TMLRP vs TUPKP): age, 75.3 ± 8.1 vs 74.6 ± 7.9 years; prostate volume, 57.8 ± 11.9 vs 58.23 ± 14.7 mL; PSA level, 4.2 ± 3.1 vs 3.8 ± 3.3 ng/mL; IPSS, 20.3 ± 7.8 vs 19.3 ± 8.2; QoL score, 4.66 ± 1.2 vs 4.5 ± 1.3; maximum urinary flow rate (Qmax), 7.9 ± 4.3 vs 8.2 ± 3.9 mL/s; postvoid residual urine volume (PVR), 97.1 ± 34.5 vs 88.0 ± 37.6 mL. There were no statistically significant differences between the two groups (P > 0.05).
The thulium laser therapeutic apparatus was as follows: maximum power 50 W, wavelength 2.01 μm, delivered via 550 μm end-firing PercuFib fibres (LISA Laser Products OHG, Katlenburg-Lindau, Germany).
The TUPKP apparatus consisted of a 26F reflux plasma prostate resectoscope (Olympus, Tokyo, Japan).
For the TMLRP operations, patients were placed in the lithotomy position, and given continuous epidural anaesthesia or lumbar anaesthesia. Saline irrigation was used, with an irrigation pressure of 40–60 cmH2O. A continuous-wave mode of the thulium laser was set, with the power at 50 W. The resectoscope was inserted through the urethra. Taking the verumontanum as an anatomical marker, hyperplasia at the urethral sphincter, apex of the prostate, verumontanum, urethral cavity, bladder neck, bilateral orifice of the ureter and intravesical condition were examined first.
For the resection, longitudinal incisions were made at 5 and 7 o'clock on the bladder neck deep to the capsule, to meet at the verumontanum level. The middle lobe was then resected reversely from the capsule to the bladder neck. Similarly, a longitudinal incision was made at 12 o'clock, and the right lobe was then pried off along the capsule from 5 to 3 o'clock in a reverse direction, and from 12 to 3 o'clock.
Tissues with fibrous and vascular adhesions were detached by laser, and eventually the right lobe tissues were resected. The left lobe was treated in the same way. To create a smooth wound and trim the apex of the prostate, a thulium laser optical fibre was fixed to the resectoscope, and the laser handle was rotated rapidly, thus enabling a rapid movement of the tip of the laser on the cutting surface. Finally, the prostate tissue was irrigated or clamped, and a three-cavity catheter was inserted.
Anaesthesia, surgical position and irrigation were the same for the TUPKP group as for the TMLRP group. The resection power was 240 W and the electric coagulation was set at 100 W. The resectoscope was inserted using the naked eye, and the bladder, orifice of the bladder neck, urethral sphincter and the ‘four zones’ (i.e. middle lobe, bilateral lobe and 12 o'clock of the prostate) were observed; particular attention was paid to the length of the prostate beyond the verumontanum and the degree of hyperplasia. Next, incisions were made at 5 and 7 o'clock, deep to the capsule, to meet the verumontanum and to form an inferior marker. An incision was then made at 12 o'clock deep to the capsule to form a marker. The bilateral lobe of the prostate was resected, and the procedure was finished by trimming the apex. ‘Slippage’ often occurred during the operation, and resection could be continued after rebooting or avoiding the dehydrated tissue. Furosemide (20–40 mg i.v.) was injected when the operation duration exceeded 60 min. ECG, serum sodium and blood oxygen saturation assessment were performed during the operation, and were adjusted according to the patient's condition. A three-cavity balloon catheter was inserted after surgery, which irrigated the bladder continuously. The catheter was removed 3 days after the operation.
As part of the assessment, operation duration and the volume of blood transfusion were measured during the operation. Blood routine and electrolytes were re-examined immediately after surgery. The irrigation time, catheterization time, postoperative hospital stay, and complications such as TURS, incontinence or urinary retention were also recorded. At the 3-month follow-up, complications such as urethrostenosis, urinary retention, drop in erectile function and retrograde ejaculation were noted.
For the statistical analyses, the SPSS 10.0 toolkit was used. Data are presented as means ± SD. Results were analysed with a matched t-test; and rate comparisons were analysed using the chi-squared test.
All 100 patients underwent successful operations and were discharged after smooth voiding was restored. They returned to the institution for a 3-month follow-up.
The mean (±SD) operation duration of TMLRP was 61.2 ± 24.2 min, compared with 30.14 ± 15.9 min for TUPKP, which was a statistically significant difference (P < 0.05) (see Table 1). In the TMLRP group, three patients had bladder irrigation whereas all patients in the TUPKP group had continuous bladder irrigation until the haematuria had sufficiently decreased (irrigation time = 2.67 ± 0.7 days).
Table 1. Patient characteristics
|Operating duration, min||30.14 ± 5.9||61.2 ± 24.2||P < 0.05|
|Patients with continuous bladder irrigation, cases||50||3||P < 0.05|
|Catheterization time, days||3.2 ± 0.6||1.8 ± 0.4||P < 0.05|
|Postoperative|| || || |
|Hospital stay, days||4.1 ± 1.3||3.3 ± 0.8||P < 0.05|
|Urethrostenosis (n)||4||0||P < 0.05|
|IPSS||7.2 ± 2.3||7.1 ± 1.5||P > 0.05|
|QoL score||1.6 ± 0.9||1.7 ± 0.8||P > 0.05|
|Qmax, mL/s||24.4 ± 7.6||24.1 ± 7.2||P > 0.05|
|PVR, mL||7.0 ± 6.5||7.2 ± 6.8||P > 0.05|
There were statistically significant differences between the groups (TMLRP vs TUPKP [mean ± SD]) for catheterization time (1.8 ± 0.4 vs 3.2 ± 0.6 days) and postoperative stay (3.3 ± 0.8 vs 4.1 ± 1.3 days) (P < 0.05). There were no statistically significant differences between the groups with regard to serum sodium, potassium and haemoglobin change (P > 0.05).
There were no intraoperative blood transfusions among the TUPKP group; however, there was a significant difference in haemoglobin in four patients before and after surgery. None of the patients had hyponatraemia. At the 1-month follow-up, four patients in the TUPKP group were diagnosed with urethrostenosis, whereas there were no patients with urethrostenosis in the TMLRP group (P < 0.05). At the 3-month follow-up, IPSS scores were 7.1 ± 1.5 and 7.2 ± 2.3 in the TMLRP and TUPKP groups, respectively; QoL scores were 1.7 ± 0.8 and 1.6 ± 0.9, Qmax values were 24.1 ± 7.2 and 24.4 ± 7.6 mL/s, and PVR values were 7.2 ± 6.8 and 7.0 ± 6.5 mL. These variables were statistically significant for each group, before and after surgery (P < 0.01); there was no significant difference between the two groups after surgery (P > 0.05). No acute urinary retention or emerging erectile dysfunction was recorded in either group.
Benign prostatic hyperplasia is a common disease in urology. In China, with an ageing population, the morbidity of BPH has been rising year by year. TURP has been considered the gold standard  for surgical treatment of BPH since the 1980s. The biggest drawbacks of this procedure are unsatisfactory haemostatic effect; high risk of TURS, due to application of non-ionic irrigation fluid such as glucose solution and distilled water; increasing risk of complications with age; and high risk of surgery among patients at high risk of developing cardiac, pulmonary and encephalic diseases. Hence, researchers have been looking for a safer, more efficacious, minimally invasive method with which to treat BPH.
Transurethral plasmakinetic prostatectomy is proven to significantly reduce TURS, and is safer and more efficacious in resection than TMLRP. TUPKP resects with two electrodes. When a current passes through these electrodes, a loop is formed that ionizes the conductor media (i.e. saline) around the electrodes to form a plasma beam. Thus, the organic molecular bond inside the target tissue is broken by the energy generated by the plasma beam, which leads to the disruption and vaporization of the target tissue. Unlike in TURP, the surface temperature of the target tissue dissected by TUPKP is only 40–70°C, and the depth of charred and coagulated tissue is <1 mm, with low thermal penetration effect (it is thus also called ‘cold cutting’) . The irrigation fluid is saline, which will not lead to dilutional hyponatraemia under normal conditions. However, if excessive irrigation fluid is absorbed, cardiac and circulatory load could be increased . The TUPKP plasma beam can generate a well-distributed coagulation layer of 0.3–1.0 mm, which has a good haemostatic effect during resection, and can significantly reduce blood loss. TUPKP has a sharp cutting action, and can incise tissues the moment they are touched; the haemostatic effect is not significantly affected because of the speed of cutting. Yang Jie et al.  compared the surgical effects of TUPKP, TURP and transurethral vaporization of the prostate (TVRP) in treating BPH; they reported that the three methods were similar in effectiveness, but that TUPKP was superior to TURP and TVRP in terms of safety.
Thulium lasers have come into clinical practice since 2004. Their physical properties are different from those of the holmium laser and the potassium titanyl phosphate (KTP) laser. The thulium laser optical fibre offers two working patterns, continuous wave and pulse wave. The major advantage of the continuous wave is the high efficiency of cutting and the marked haemostatic effect. Its current application is mainly resection of the prostate. The major advantage of the pulse wave is its high precision of cutting, and it is mainly applied to diseases such as contracture of bladder neck and urethrostenosis. The wavelength of the thulium laser ranges from 1.75 to 2.2 nm, with a mean of 1.91 μm, which is close to the 1.92 μm water absorption peak in tissue, allowing a higher absorption of the laser in surgery. On the one hand, this results in more efficient and rapid tissue cutting, and on the other, less heat damage is generated during the operation, thus reducing cicatrization and stricture formation after surgery. According to the urology research centre of Johns Hopkins, a 500–2000 μm thermal coagulation band was observed with a haematoxylin & eosin (H&E) stain on a postoperative prostate resection specimen, thus proving that the thulium laser provides adequate haemostatic effect for blood vessel-rich tissues (e.g. the prostate); the thulium laser resects and vaporizes large amounts of prostate tissue when cutting . Fried  reported that, at 50 W power, a continuous wave of thulium laser optical fibre evaporates tissue at 0.45 g/min. Meaning resected tissues and vaporized tissues are nearly the same size and operation duration is significantly reduced.
Thulium laser resection of the prostate resects directly to the surgical capsule from the inside to the outside and in different lobes. Sections affecting the infusion of fluid, which often happens to the middle lobe, are treated with priority; other sections are treated afterwards. The combination of highly efficacious cutting and rapid vaporization has proved the advantage of the thulium laser, with its good haemostatic effect and high safety. Compared with TUPKP, the excellent cutting and haemostatic features of the thulium laser allow good visibility throughout surgery. Zhuo et al.  reported that even a relatively large amount of arterial bleeding could be well managed in TMLRP, and the good visibility enabled the surgeon to cut more precisely along the surgical capsule. The hyperplasia was resected thoroughly, with nearly no residual gland, and bleeding was significantly reduced during and after surgery, with the advantage of high safety and quick recovery. Compared with TUPKP, the advantages of TMLRP are as follows: it is a nearly bloodless procedure, both during and surgery, and there is no significant difference in haemoglobin before and after surgery; urine is clear after surgery, and continuous bladder irrigation is unnecessary; decatheterization takes place 1–2 days after surgery, and there is a shorter hospital stay; and TURS is avoided. However, the operation duration of TMLRP is slightly longer than that of TUPKP; TUPKP is superior to TMLRP with regard to safety and efficacy, with nearly no TURS; TMLRP is safer than TUPKP; and all patients with BPH suitable for TUPKP are also suitable for TMLRP. For patients with larger prostate volume, however, the operation duration of TMLRP is significantly longer than that of TUPKP; hence, TUPKP is a better choice. Moreover, at postoperative follow-up there was a higher morbidity of urethrostenosis in TUPKP; this could be because the surgical resectoscope had a thicker sheath. There was no significant difference between the two groups with regard to complications of acute urinary retention, pressure incontinence, emerging erectile dysfunction and retrograde ejaculation.
In the present study, the efficacy and indications of TMLRP and TUPKP were very similar. TUPKP had a low incidence of urethrostenosis, was nearly bloodless during surgery and was safer than TUPKP; nevertheless, TUPKP is more suitable for patients with larger prostate volume.
Conflict of Interest