Transurethral plasma vaporization of the prostate: 3-month functional outcome and complications

Authors


  • A study from the French Urological Association Committee for Benign Prostatic Hyperplasia and Lower Urinary Tract Symptoms (CTMH-AFU).

Grégoire Robert, Bordeaux Pellegrin University Hospital, Department of Urology, Place Amélie Raba Léon, 33000 Bordeaux, France.e-mail: gregoire.robert@chu-bordeaux.fr

Abstract

Study Type – Therapy (multi-centre cohort)

Level of Evidence 2b

OBJECTIVE

To evaluate the early functional outcomes of transurethral plasma vaporization of the prostate (TUVis) in a multicentre study.

PATIENTS AND METHODS

A prospective multicentre observational study was conducted in eight urology departments. The inclusion criterion was benign prostatic hyperplasia (BPH) requiring surgical treatment. Patients on anti-coagulant therapy were not excluded. The TUVis procedure was performed according to a classic transurethral resection of the prostate (TURP) scheme following the manufacturer’s recommendations. We evaluated subjective functional outcome using self-questionnaires (International Prostate Symptom Score [IPSS] and five-item International Index of Erectile Function [IIEF-5]) and objective criteria (prostate volume, prostate-specific antigen [PSA], uroflowmetry, post residual volume) at baseline and at 1- and 3-month follow-ups. All types of complications were systematically recorded.

RESULTS

Despite 52% of patients receiving anticoagulant therapy before surgery, we reported only 3% with haemorrhagic complications, no blood transfusion, a mean catheterization time of 44 h and a mean postoperative stay of 2.9 nights. No significant change in irrigation time, catheter time or hospital stay was observed in patients with or without anticoagulant therapy. The IPSS and bother scores significantly decreased after the 3-month follow-up (57% and 59%, respectively), but the average remaining prostate volume was 29 cc and the tissue ablation rate was only 0.5 cc/min. Three major complications occurred, consisting of two urinary fistulas and one partial bladder coagulation.

CONCLUSIONS

The TUVis procedure has a proven fast postoperative recovery time, good short-term functional outcome and good haemostatic efficiency. However, the tissue ablation rate was lower than expected and we encountered three major complications, the mechanisms of which remain unclear. Considering the high energy level required to create the plasma effect, the generator, cable and resectoscope must be carefully checked before each procedure.

Abbreviations
TUVis

transurethral plasma vaporization of the prostate

Hb

haemoglobin

Ht

haematocrite

Na

natraemia

LMWH

low-molecular weight heparin

TUVP

trans-urethral bipolar vaporization of the prostate

INTRODUCTION

TURP is the gold standard for the endoscopic treatment of BPH [1]. Nonetheless, it remains associated with significant morbidity, especially in terms of haemorrhage complications leading to delayed hospital discharge and possible blood transfusion [1–3]. Currently, approximately 30% of patients are admitted for surgery with cardio-vascular diseases and ongoing anticoagulant therapy responsible for an increased risk of haemorrhagic complications [1,2]. Therefore, besides being as efficient as TURP in urinary symptom improvement, new techniques have to be less invasive and provide better haemostasis.

Transurethral plasma vaporization of the prostate (transurethral vaporization in saline: TUVis; Olympus Europe, Hamburg, Germany) is a new technique which is proposed to challenge TURP. It is derived from Girus PlasmaKinetic vaporization, using the same principle but different loop shapes and generator settings.

The aim of the present study was to evaluate the early clinical outcome of the TUVis technology in a multicentre study.

PATIENTS AND METHOD

We conducted a prospective multicentre observational study in eight urology departments in France. The inclusion criteria were symptomatic and/or complicated BPH requiring surgical management. The exclusion criteria were clinical or biological suspicions of prostate cancer and a history of TURP.

The baseline evaluation included assessment of medical history, prostate volume, Qmax, PVR and blood analysis including PSA, haemoglobin (Hb), haematocrite (Ht) and natraemia (Na). All patients except those with a urinary catheter or an inability to understand questionnaires were asked to complete the IPSS including bother questions and the five-item International Index of Erectile Function (IIEF-5). The surgical procedure was evaluated by surgical time as well as by intra- and postoperative complications. During the postoperative stay, urinary retention, bladder washout, blood transfusion, bladder irrigation time, urinary catheter time, postoperative hospital stay and Hb, Ht and Na on the first post-operative day were collected. Functional outcome was assessed after 1 (IPSS and bother score) and 3 months (prostate volume, Qmax, PVR, PSA, IPSS, bother score and IIEF-5).

Plasma vaporization of the prostate was performed using a bipolar high-frequency generator (Olympus UES-40 HF or Erbe VIO-300D) and a 26-Fr continuous flow bipolar resectoscope (Olympus OES-Pro TURis). The procedure was performed according to a classic TURP scheme, starting at the bladder neck and continuing onto the lateral and anterior lobes of the prostate. Isotonic 0.9% sodium chloride solution at 37 °C was used as the irrigant and a continuous in-and-out flow was maintained during surgery.

Statistical analysis was performed with Prism 5.0 (2009, GraphPad Software Inc., La Jolla, CA, USA). Mann–Whitney t-tests were calculated to compare the data. The study protocol was approved by the local ethical committee and all patients gave written informed consent.

RESULTS

STUDY POPULATION

A total of 106 consecutive patients fulfilled the inclusion criteria and were enrolled in the study over a 3-month period. Each centre included a range of 5 to 20 patients. A maximum of three surgeons per centre participated in the study resulting in an average of seven procedures per surgeon (range 2 to 14). No specific TUVis training was provided but all of the surgeons were experienced in BPH endoscopic surgery.

The baseline characteristics of the study population are presented in Table 1. Of the 55 patients receiving anticoagulant therapy before surgery, 22 received anti-vitamin K, 32 received aspirin and 15 received bicalutamid. Six patients received a combination of aspirin and bicalutamid and eight patients received a combination of either aspirin or bicalutamid and anti-vitamin K. Anti-vitamin K was interrupted before surgery in 22 patients and replaced by low-molecular weight heparin (LMWH) in 21. Aspirin was interrupted in 17 patients but maintained in 15. Bicalutamid was interrupted in 14 patients but maintained in 1.

Table 1.  Patient characteristics at baseline
 Number of valuesPercentage or mean (±SD)Range
  1. PVR, postvoid residual volume; Qmax, maximum urine flow rate; IPSS, International Prostate Symptom Score; QOL, bother questions of the IPSS score; IIEF-5, five-Item International Index of Erectile Function.

Age (years)10672.3 (±9.5)44.5–90.6
Anticoagulant therapy10621% anti-vitamin K 39% aspirin ± bicalutamid
Medical history10643% cardiovascular disease 11% diabetes 4% cognitive deficiency 2% dialysis 
Urinary catheter before surgery10629% acute retention 12% chronic retention
Prostate volume (cc)10646.0 (±17.5)  12–100
IPSS7820.0 (±8.4)   3–35
QOL784.7 (±1.4)   1–6
IIEF-5698.7 (±8.7)   0–24
PSA (ng/mL)773.4 (±3.4)0.2–21
Qmax (mL/s)3910.1 (±6.1)   3–40
PVR (mL)5398.9 (±136.4)   0–550

Of the 42 patients with a urinary catheter, 29 had presented with an acute urinary retention within 2 weeks before surgery and 13 had been catheterized for chronic urinary retention more than 6 weeks before surgery.

Patients with a prolonged urinary catheter (n= 13), cognitive deficiency (n= 4) or an inability to understand French (n= 2) were not asked to complete the questionnaires. The IPSS score at baseline was completed by 78 patients (90% of evaluable patients) and the IIEF-5 score by 69 patients (79%).

SURGICAL PROCEDURE AND POSTOPERATIVE STAY

The TUVis procedure was successfully performed in all cases but one: a severe haemorrhage occurred at the very beginning of the procedure and conversion to monopolar TURP was decided.

The comparison of blood analyses between baseline and day 1 (Fig. 1) showed a significant decrease in haemoglobinemia (from 13.5 to 12.7 g/dL; P= 0.009) and non-significant decreases in Ht and Na (from 40.4 to 38.5% and from 138.7 to 137.8 mmol/L; P= NS, respectively).

Figure 1.

Natraemia, haemoglobinemia and percentage haematocrite at baseline (B) and at day 1 (D1). Bars: mean; plots: 95% confidence interval; ** P-value <0.001, NS: non-significant P-value, Mann–Whitney t-test compared with baseline.

Surgical time, vesical irrigation time, catheterization time and length of hospital stay are presented in Table 2. Patients with a urinary catheter before surgery (n= 42) had a longer catheterization time (55 ± 39 hours; P= 0.031) but no significantly longer hospital stay (3.4 ± 2.2 nights; P= 0.127). Patients receiving anticoagulant therapy before surgery (n= 55) had no significantly longer surgical time (55 ± 19 min; P= 0.356), no significantly longer irrigation time (22 ± 15 h; P= 0.332), no significantly longer catheterization time (45 ± 39 h; P= 0.712) and no significantly longer hospital stay (2.9 ± 2 nights; P= 0.949).

Table 2.  Surgery and postoperative outcomes
 Mean (±SD)Range 
Operating time (min)53.6 (±17.8)15–12084%≤ 60 min
Irrigation (h)20.4 (±14.5)0–9692%≤ 24 h
Urinary catheter (h)44.1 (±34)6–24083%≤ 48 h
Postoperative stay (nights) 2.9 (±1.8)1–1156%≤ 2 nights

Eighteen patients (17%) presented with postoperative complications that are further described in Table 3. Urinary retention occurred in 12 patients and 11 had to be discharged with a urinary catheter. Ten had been admitted with a urinary catheter before surgery (83%).

Table 3.  Complications and treatment during hospital stay and 3-month follow-up
 Type of complicationnTreatment applied
  1. TURP, transurethral resection of the prostate; NSAIs, nonsteroidal anti-inflammatory drugs.

Before hospital discharge (106 patients)Urinary retention12Prolonged catheterization and second trial without catheter
Failure to void 11Prolonged catheterization and third trial without catheter after 1 month
Haematuria3Bladder washouts and prolonged hospital stay
Persistent pelvic pain3Analgesics, prolonged catheterization and prolonged hospital stay
Urinary infection2Oral antibiotherapy
Peroperative haemorrhage1Conversion to normal TURP
After 1- and 3-months follow-up (100 patients)Bothersome irritative symptoms14Medical treatment with NSAIs and/or anticholinergic therapy
Urinary retention9Urinary catheter ± complementary TURP
Urinary infection6Oral antibiotherapy
Treatment failure84 TURP 1 green-light laser 3 urinary catheter
Haematuria4Hospitalization and bladder washouts
Urinary fistula and incontinence2Prolonged catheterization and urinary diversion
Bladder necrosis1NSAIs and anticholinergics
Heart attack1Cardiologic intensive care and coronary stent
Meatus stricture1One month self-catheterization

FUNCTIONAL OUTCOMES

Completed 1- and 3-month follow-ups were made by 100 patients (94%): 4 patients (3.8%) were lost to follow-up and 2 patients (1.9%) died before the assessment of functional results (non-surgery related deaths).

The mean IPSS score (Fig. 2) decreased from 20 to 12 after 1 month (P < 0.001) and to 8.6 after 3 months (P= 0.005 compared with 1 month). The mean bother score decreased from 4.7 to 3.2 after 1 month (P < 0.001) and to 1.9 after 3 months (P < 0.001 compared with 1 month). The mean prostate volume decreased from 46 to 29 cc (P < 0.001; 95% CI = 25–33), PVR from 99 to 18 mL (P < 0.001; 95% CI = 10–27) and PSA level from 3.4 to 2.4 ng/mL (P= 0.016; 95% CI = 1.7–3.1). In the meantime, Qmax increased from 10.1 to 15.5 mL/s (P < 0.001; 95% CI = 13–18).

Figure 2.

International Prostate Symptom Score (IPSS) and bother scores at baseline (B), after 1-month follow-up (M1) and after 3-months follow-up (M3). Bars: mean; plots: 95% confidence interval; ** P-value <0.001, *** P-value <0.001, Mann–Whitney t-tests).

Twenty-one patients had reported bothersome irritative symptoms during the follow-up period. After 3 months, 69% of the patients were satisfied with the results of surgery and 14% were dissatisfied.

Eight patients had shown evidence of treatment failure: three patients had to retain the urinary catheter and five underwent a complementary surgical procedure (four TURP and one laser vaporization). Four of the treatment failures (two urinary catheters and two TURPs) occurred in patients who had been admitted with a urinary catheter before surgery.

The mean tissue ablation rate was 0.5 cc/min (ΔVolume/surgical time) and ranged from 0.04 to 1.1 cc/min. Comparing patient groups with prostate volumes of ≤30 cc and ≥45 cc 3 months, we found that the ratio of surgical time/baseline prostate volume was shorter in the ≥45 cc group than in the ≤30 cc group: 0.9 and 1.4 min/cc (P= 0.003), respectively (Table 4).

Table 4.  Comparison of patient groups according to 3-month follow-up prostate volume (≤30 vs ≥45 cc)
 ≤30 cc≥45 ccP-value
Surgical time: mean ± SD (min)51.0 ± 14.365.6 ± 18.60.03
Baseline prostate volume: mean ± SD (cc)36.4 ± 11.071.4 ± 17.6<0.001
Surgical time/baseline prostate volume 1.4 ± 0.4 0.9 ± 0.30.003

COMPLICATIONS

The delayed complications are listed in Table 3. Haemorrhagic complications leading to hospitalization and bladder washouts occurred in four patients, including two patients receiving anticoagulant therapy before surgery. Urinary infections requiring antibiotic treatments were reported in six patients, including five patients with a urinary catheter before surgery.

Three major complications were observed in three patients 2 weeks after the TUVis procedure: two with necrosis of the urethra leading to urinary fistulas (Fig. 3) and one bladder necrotic aspect leading to severe irritative symptoms. These complications occurred in the same centre, in three consecutive patients, operated on by two surgeons using the same resectoscope and the same generator (Erbe VIO-300D). The two fistulas were associated with an endoscopic bladder necrotic aspect, bladder retraction and urinary incontinence: urinary diversion had to be performed in both cases. In the last patient, bladder partial necrosis healed spontaneously over a 2-month period. At the 3-month follow-up, this patient had completely recovered (spontaneous voiding, IPSS = 1 and bother = 1).

Figure 3.

Complete necrosis of the urethra and urethrocutaneous fistula (6 weeks after TUVIS).

Two other centres using the Olympus UES-40 HF generator also reported four cases of endoscopic necrotic aspect of the urethra. These patients had major irritative complaints but this had healed after 3 months. No urethral stricture was diagnosed in the follow-up (6 months).

DISCUSSION

The TURP procedure, the most frequently performed BPH surgical treatment, is the gold standard that all new techniques have to challenge. To the best of our knowledge there is only one controlled study comparing TURP with Girus trans-urethral bipolar vaporization of the prostate (TUVP) [3]. Since the manufacturer has changed the loop shape and the bipolar generator settings, the results of this study cannot be compared with TUVis. In all, 149 patients were randomized to TURP or TUVP and followed-up during a mean of 8.5 months. There was no difference between the two groups in terms of IPSS, Qmax or PVR, but the hospital stay was slightly longer (3.4 vs 3.0 nights; P= 0.002) and blood transfusions were more frequently required (4 vs 0) in the TURP group.

The first TUVis clinical trial was reported by Reich et al. [4] where 30 patients were evaluated in two different centres and followed-up during 6 months. The authors did not report any intra- or postoperative complications and showed excellent 6-month functional results (IPSS = 8.1). Geavlete et al. [5] recently published the first randomized clinical trial: a total of 155 patients were randomized to TUVis (n= 75) or TURP (n= 80) and followed-up during 6 months. The catheterization period and hospital stay were significantly shorter for TUVis than for TURP patients (respectively 24 vs 71 h and 48 vs 93 h; P < 0.05) and there was no blood transfusion in the TUVis group vs 6.25% in the TURP group. After 6-month follow-up, the IPSS score was 5 in the TUVis group vs 9.1 in the TURP group (P= 0.02) and all the follow-up data were slightly better in the TUVis group (e.g. Qmax, PVR, prostate volume, PSA). To the best of our knowledge there is no other published study evaluating the new TUVis device.

The present study was not controlled but included 106 consecutive patients in eight different centres and can therefore be compared with other observational studies on TURP.

IMMEDIATE COMPLICATIONS

The TURP morbidity has been extensively studied in large prospective observational studies: haemorrhagic complications occur in 10% to 30% and blood transfusions in 3% to 5%[2,6,7]. Despite 52% of patients undertaking anti-coagulant therapy, we only observed three postoperative haemorrhagic complications (2.8%) and no need for blood transfusion. The short irrigation time (≤24 h for 92% of patients), the short catheterization time (≤48 h for 83% of patients) and the short hospital stay (≤2 nights for 56% of patients) confirmed the good haemostatic efficiency of TUVis. These results were confirmed in patients receiving anticoagulant therapy before surgery: we did not find any differences in terms of surgical time, irrigation time, catheterization time or length of hospital stay. The deeper coagulation depth observed after TUVis may explain the excellent immediate haemostasis: in an experimental model, Reich et al. [8] calculated that the coagulation depth was 2.1 mm with TUVis compared with 0.9 mm with TURP. The lower rate of capsular perforation with bipolar energy may also be an explanation, as an experimental porcine kidney model confirmed that monopolar TURP led to capsular perforation in all cases whereas TUVP only led to 60% of cases with capsular perforation [9].

FUNCTIONAL OUTCOME

The TURP urinary symptom improvement was assessed in a recent prospective randomized study comparing TURP with contact laser prostatectomy and electrovaporization [10]. In the latter study, the IPSS score at baseline was 24.6 in the TURP group compared with 20.0 in the present study. After 3 months, they went down to 7.4 and 8.6, respectively. We also observed significant Qmax (+53%) and PVR (−81%) improvements that were similar to those found using TURP but this has to be confirmed with a long-term follow-up. Finally, the IPSS improvement in the present study (57%) was similar to that of a previously published TUVis study (60%) [4].

PROSTATE VOLUME REDUCTION

The reduction in prostate volume was less pronounced than expected. After the 3-month follow-up, the mean prostate volume had decreased from 46 to 29 cc, 16.7% of patients had a residual prostate volume larger than 45 cc and four patients needed complementary surgical treatment because of insufficient prostatic volume reduction associated with persistant urinary symptoms.

In vitro, Reich et al. [8] found that the TUVis tissue ablation rate was approximately 3.8 cc/min compared with 6.5 cc/min for TURP. In the present study, the tissue ablation rate was lower than expected: 0.5 cc/min (surgical time lasted from the introduction of the resectoscope to its removal). This discrepancy may be related to the learning curve: all surgeons started the study without training and only seven procedures per surgeon were performed on average. A further explanation is the modification of tissue conductivity over time: the addition of several passages of the loop onto the same area coagulates the tissue deeper and creates a thermal barrier which progresses over time and impairs the vaporization effect of the TUVis.

The 3-month prostate volume was larger than expected (29 cc). The first explanation is that the surgeon did not spend the necessary time for ablation of the BPH tissue: the surgical time in patients with a residual prostate volume ≥45 cc was too short (only 0.9 min/cc). The TUVis procedure requires more than 1 min to remove 1 cc of prostatic tissue and this is certainly longer than the TURP procedure. The second explanation is that the deeper coagulation impaired the identification of the white aspect of the prostatic capsule which is used as the classic landmark of a complete TURP. It is worth noting that Gaevelette et al. [5] recently published completely different results on this particular issue. Despite the baseline prostate volume was 56 cc in both groups and the surgical time was significantly shorter in the TUVis group (35 vs 50 min; P= 0.002), they found equal residual prostate volumes in the TUVis and TURP groups after 6-month follow-up (16.8 vs 18.5 cc; P= 0.181). The lack of surgeons’ training in the present study could be an explanation for this discrepancy but this issue remains unclear and has to be further studied.

DELAYED COMPLICATIONS

Two urinary fistulas, one major bladder injury and at least four other minor urethral injuries were registered during the present study.

The worse adverse events occurred within the same centre, in three consecutive patients, treated by two surgeons, using the same Olympus resectoscope and the same Erbé generator. Among the possible explanations a human error or a material deficiency have to be considered. Nonetheless, one of the surgeons involved was already practiced in this method (14 previous TUVis performed) and did not notice any abnormalities during the procedure. An expertise of the material is under way to better understand these adverse events.*

To the best of our knowledge, no other such cases of adverse events have been reported so far despite the fact that more than 10 000 procedures have been performed (manufacturer’s data). Investigations are ongoing to understand the reasons for this accident. Until then, we recommend that the resectoscope, cable and generator are carefully checked before each procedure.

In conclusion, the TUVis procedure was proved to offer good short-term efficacy (57% IPSS decrease) as well as a fast postoperative recovery rate (2.9 nights after surgery). Even for the 52% of patients undergoing anti-coagulant therapy, this procedure showed good haemostatic efficiency without any need for blood transfusion. Nonetheless, the remaining prostate volume after surgery was larger than expected (29 cc) and sufficient time must be spent during surgery to completely remove the BPH tissue: more than 1 min/cc.

Finally, we encountered three major complications (e.g. two necrosis of the urethra and one bladder necrotic aspect), the mechanisms of which remain unclear. Considering the high energy required to create the plasma vaporization effect, the surgeon must be trained and the electrode insulation must be checked before and after each procedure*.

CONFLICT OF INTEREST

None declared.

Footnotes

  • *

    Correction added after online publication 2-11-2010: this paragraph has been altered since the original version of this article was published.

  • *

    Correction added after online publication 2-11-2010: this sentence has been altered from the original version of the article published.

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