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Prostate Cancer and Prostatic Diseases (2007) 10, 316–322
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REVIEW
Photoselective vaporization of the prostate (GreenLight PV): lessons
learnt after 3500 procedures
F Gómez Sancha1, A Bachmann2, BB Choi3, S Tabatabaei4 and GH Muir5
1
Institute of Advanced Urological Surgery, Madrid, Spain; 2Department of Urology, University Hospital, Basel, Switzerland;
Department of Urology, Weill Medical College of Cornell University, New York, NY, USA; 4Department of Urology, Massachusetts
General Hospital, Boston, MA, USA and 5Department of Urology, King’s College Hospital, London, UK
3
The technical recommendations of an international group of experts on photoselective vaporization
of the prostate (PVP; GreenLight PV) for benign prostatic hyperplasia are described. Their
experience stems from the treatment of over 3500 patients at five centres in Europe and the United
States. The objectives of this physician-based initiative are to optimize the results achieved with
PVP by standardizing the procedure, as well as to recommend training requirements.
Prostate Cancer and Prostatic Diseases (2007) 10, 316–322; doi:10.1038/sj.pcan.4500989; published online 10 July 2007
Keywords: photoselective vaporization; BPH; laser therapy; KTP; PVP; GreenLight PV
Introduction
Benign prostatic hyperplasia (BPH) is a very common
condition in the ageing male. A number of minimally
invasive procedures have been developed with the
objective of matching or increasing the efficacy of
transurethral resection of the prostate (TURP) and
lessening the associated morbidity. These include transurethral needle ablation (TUNA), which uses low-level
radiofrequency energy to ablate prostate tissue, thermal
ablation of prostate tissue using microwave energy and
laser therapy. Holmium laser ablation of the prostate was
first described in 1995 using the holmium:yttrium–
aluminium–garnet (Ho:YAG) laser, which operates at a
wavelength of 2100 nm.1 It is considered that tissue
vaporization with the Ho:YAG laser is limited due to its
high absorption by water. As a result, the laser fibre must
be kept in direct contact with the tissue to achieve a
relatively slow vaporization, which allows the treatment
of very small (20–30 g) prostate glands. The technique
was modified so that the pulsatile formation of vapour
bubbles at the tip of the end firing optical fibres could
be used to cut tissue, mimicking the surgical effects of
TURP. Subsequently, with the introduction of a mechanical tissue morcellator/aspirator, Ho:YAG laser enucleation of the prostate (HoLEP) evolved. Recent results
suggest that clinical outcome with HoLEP was comparable to TURP,2 but it has not been widely adopted as
it is technically challenging and has a steep learning
Correspondence: GH Muir, Department of Urology, King’s College
London, King’s College Hospital, Denmark Hill, London SE5 9RS,
UK.
E-mail: [email protected]
Received 25 April 2007; accepted 7 May 2007; published online 10 July
2007
curve. It has been recommended that a minimum of 50
procedures on smaller (o50 ml) prostate should be
performed before larger prostate enucleations are attempted.3
Photoselective vaporization of the prostate (PVP)
using the 80-W potassium–titanyl-phosphate (KTP) laser
was first reported in 2003 in a pilot study involving men
with prostates sized 24–76 ml with good outcome and
minimal morbidity.4 The unique 532 nm wavelength that
the laser operates at is highly absorbed by oxyhaemoglobin and minimally absorbed by water. This high
absorption in haemoglobin limits the optical penetration
depth of the KTP laser to 0.8 mm.5 Vaporization occurs
from within the tissue where vapour bubbles form and
burst the collagen matrix. The heat remaining in the
tissue induces a coagulation zone of only 1–2 mm
thickness. Although sufficient to achieve haemostasis,
this may limit the large coagulation zone thought to be
linked to postoperative oedema formation and irritative
symptoms seen in Nd:YAG lasers.6 The primary difference between PVP and HoLEP is that PVP involves
prostate tissue ablation through vaporization as opposed
to enucleation. There has been a rapid and widespread
acceptance of PVP worldwide, primarily due to its
efficacy, safety and patient acceptance. Training recommendations are yet to be established, however, and
training is considered an area for improvement.
In this context, this paper describes the recommendations of an international group of experts on the PVP for
BPH using GreenLight PV from its initial introduction
into the clinical practice in 2002. Their experience stems
from the treatment of over 3500 patients at five centres in
Europe and the United States.7–10 The objectives of this
physician-based initiative are to optimize the results
achieved with PVP by standardizing the technique and
to recommend training requirements.
Photoselective vaporization of the prostate
F Gómez Sancha et al
The procedure
Equipment
The equipment involved in the PVP procedure is listed in
Table 1. The technique described in this paper involves
the GreenLight PV 80-W KTP laser system (laserscope).
Although a modification of this system generating 120 W
of power is becoming available, clinical experience with
this equipment will be presented in future publications.
Patient evaluation
A standard preoperative workup according to the
European Association of Urology and the American
Association of Urology guidelines for any surgical
procedure is conducted on the patient before the PVP
procedure. Mandatory assessment includes evaluation of
prostate size, as this has implications for the operating
time. Transrectal ultrasound and computed tomography
scan are the most reliable means to assess size and are
preferable to digital rectal examination. Routine preoperative evaluation according to local guidelines is
performed.
Preoperative patient preparation
Although there are studies showing that this procedure
can be safely performed under anticoagulation, provided
it is safe for the patient’s overall medical condition,
antiplatelet (aspirin) and anticoagulation (warfarin)
medications should be discontinued preoperatively, if
possible. However, in experienced centres, such high-risk
patients can be considered for operation; heparin or an
equivalent high-molecular-weight anticoagulant should
replace warfarin.11,12 Appropriate prophylactic antibiotics should be given perioperatively. Temperature monitoring of the patient is recommended and warm air
blankets are applied, if necessary. Full-length elastic
stockings or a sequential compression device should be
used in addition to any local policies for deep vein
thrombosis prophylaxis.
317
Anaesthesia
Two forms of anaesthesia may be applied: general or
spinal. The use of a paralytic agent for muscle relaxation
is not necessary during the procedure. Local anaesthesia
is generally not recommended. However, periprostatic
block with sedation can be used in certain special
circumstances, for example significant cardiac risk
patients with relatively small gland.
Operative technique
The surgeon may stand or sit (preferably on a chair with
back and arm rests). The patient is positioned in a
modified lithotomy position with the legs in stirrups.
Special attention should be given to avoid dramatic
flexion and abduction of the hips and knees, which could
affect blood supply to the lower extremities or cause
neuropraxia. A video system is mandatory: the camera
equipment is set up with a special 532 nm lens filter
inserted between the camera and the telescope. This filter
protects the camera and must be kept dry before and
during the procedure to avoid image distortion. Both the
camera and the filter should be protected from water
Table 1 The equipment involved in the photoselective vaporization of the prostate technique
GreenLight laser system 80 W output
Laser fibre: 600 mm core diameter and is equipped with a 1800 mm quartz cap; side-firing; The beam has a forward deflection of 701 and a
divergence angle of 151. It has a red marker to indicate the side of firing and blue marker to indicate opposite side to firing. A knob allows the
surgeon to manipulate the fibre and also has a mark to indicate the side of firing
Continuous flow laser cystoscope which accepts the GreenLight fibre
301 telescope (it is also possible to use a 121 scope) with a 7 French inner laser bridge and an external sheath with a beak visual obturator
Self-sealing nipple to avoid water leakage around laser fibre
Video system with camera cover to prevent water penetration
Filtering laser mechanism for camera protection
Continuous flow pump, gravity or suction (optional)
Room temperature saline irrigation system
Urethral dilators or otis urethrotome plus lubricant (standby)
Catheter (standby)
latex or silicone
16–20 French (large bore catheters not usually necessary for this procedure)
2 or 3 way (irrigation is usually not necessary)
Laser goggles
Suprapubic trocar (optional); resectoscope and diathermy machine (standby)
Chair with arm rest (optional)
All items are essential unless indicated.
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318
during the procedure using a laparoscopy sheath. The
white balance is then checked. Laser goggles specifically
filtering the 532 nm wavelength should be worn by all
members of the team and any colour distortion that
results noted, for example, the blue triangle on the laser
tip indicating direction may appear in a different colour.
The local laser safety protocol should be adhered to. It is
important to remind the entire operating team about
colour distortion, as some medications and instruments
are colour coded and mistakes could occur if attention is
not paid to colour changes due to the camera filter.
The external sheath of the laser cystoscope has a beak
at the tip that is not visualized with a 301 lens (it is seen
with a 121 scope). The scope should be equipped with an
optical obturator, which should be gently introduced
through the urethra so as to limit any local damage and
bleeding caused by this beak, particularly with a large
median lobe prostate. Indeed, scope movements should
always be gentle throughout the procedure for this
reason. Irrigation is started and visualization made of the
anatomy of the urethral sphincter and prostate; the
position of the ureters and the bladder neck are also
noted. The optical obturator is removed and replaced by
the laser carrier and the laser fibre is introduced, which
should be set up with no torque in the lead to reduce any
resistance that might damage the laser fibre. Finger tip
adjustments of the laser fibre position within the prostate
are recommended rather than using rotation of the arm
or wrist, as this assists manipulation and prevents
fatigue. The fibre should be placed at an adequate
distance from the telescope lens to prevent damage to the
latter or to the cystoscope’s beak. Constant visibility of
the laser fibre tip should be maintained; it is best to keep
the blue triangle on the fibre in view at all times. The
power is set at 80 W for laser vaporization. The most
important treatment parameter for efficiency and speed
is the working distance, for example, the separation of
the fibre and the tissue. Although it is important to keep
a close contact between the laser and the tissue, it is
important that a short distance be maintained. The laser
is fired perpendicularly in lateral side-to-side slow
sweeping movements (Figure 1), which are distinct from
the back and forward actions of a TURP loop. If the laser
fires at too great a distance from the tissue, then
coagulation and not vaporization will result. Direct
contact with the prostate tissue should also be limited
to prevent degradation of the fibre, although this is
sometimes inevitable, particularly in patients with large
median lobes. Effective vaporization is indicated by
bubble formation when the laser is fired. Vigorous
bubble formation from effective vaporization can, at
times, create subtle vibration of the laser fibre, which can
be felt by the surgeon’s hand. It is recommended that
long continuous periods of vaporization are aimed for
rather than intermittent (on/off) usage, as this will
optimize energy usage and so improve efficacy. With
increased experience, longer periods of laser firing will
become possible achieving optimal debulking (Figure 2).
During vaporization, tissue may adhere to the tip of the
fibre requiring it to be cleaned. Two options can be
considered for this process: turn the laser off and clean
with a gauze outside the body; or with experienced
operators, remove the tissue in situ by rubbing the
turned-off laser in an upward motion towards the tip of
the fibre against previously lasered tissue.
Prostate Cancer and Prostatic Diseases
Figure 1 Photoselective vaporization of the prostate. The fibre
should be rotated in a sweeping fashion with rotation amplitude
reduced to an arc of 601 (c) to avoid an overt increase in distance
from the fibre to the tissue, which would reduce vaporization
efficiency and increase coagulation (a, b).
Tissue vaporization strategies
The ultimate goal of tissue vaporization is to create a
non-obstructive prostatic urethra that is smooth and
easily catheterizable. To achieve this goal, the operator
should develop a methodical approach to the laser
vaporization that is safe, efficient and reproducible. In
terms of overall tissue ablation, the operator should aim
to generate smooth tissue surfaces and to remove tissue
in a uniform and systematic manner. As with TURP,
there are several approaches that can be taken and no
single method is recommended.
The Malek technique. In the Malek procedure, the
lateral lobes of the prostate are vaporized starting at
the bladder neck.13 The laser beam is moved slowly
along the length and breadth of each lobe, taking care at
the apex to avoid the external sphincter. The lobes are
ablated evenly to the level of the capsular fibres. The
median lobe is then vaporized to the level of the
transverse fibres of the vesical neck. In the case of large
median lobes, this is partially ablated before the lateral
lobes to facilitate the movement of the scope and
irrigation.
The vaporization incision technique. A modified technique that can be applied for large volume prostates has
been developed.14 The technique consists of a midline
incision in the median lobe that is carried down to
trigone. A second incision is made lateral to the median
lobe and the tissue in between is vaporized. A
contralateral procedure is performed. A high lateral lobe
incision is then made and carried down to the floor of the
prostate on both sides. The apex is vaporized last.
The spiral technique. The objective of the spiral technique is to develop a clear cavity in a stepwise fashion, as if
spiralling down through the prostate (Figure 3a). The
basic principle is to vaporize a single area completely at
any one time. Vaporization starts at the middle lobe and
then the bladder neck followed by the proximal lateral
lobes, which are sometimes dealt with in several stages
(Figures 3b–e). The final stages are the floor of the
prostate and the apex. It can be difficult to determine the
prostate capsule, as the lasered tissue can develop a
Photoselective vaporization of the prostate
F Gómez Sancha et al
Novice:
250,000 joules
Expert:
180,000 joules
319
0
2h 15min
Laser on
0
1h 10min
Laser off
Figure 2 Representative pattern of energy usage by experienced operators of the photoselective vaporization of the prostate technique
compared with inexperienced operators. With experience, surgeons keep the pauses to a minimum during the procedure, increasing
efficiency and reducing overall surgical time. Outcome in a typical 60 g prostate is shown.
Figure 3 The spiral technique showing: (a) the principle of spiralling down through the prostate; (b–e) vaporization starting at the middle
lobe, then the bladder neck followed by the proximal lateral lobes.
fairly homogenous appearance. Certainly, at the end of
the procedure, the verumontanum should be clear of
obstruction and there should be a clear passage from the
apex to the bladder base. Occasionally, a large middle
lobe may be encountered, which can be a problem at the
end of vaporization as a tiny flap of middle lobe may
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obscure the ureters. In such rare instances, a miniresection of the residual middle lobe should be considered.
the appearance of the prostate tissue following the
procedure is more ragged than that resulting from a
TURP.
The anterior start technique. This procedure has been
developed in Madrid and New York centres.15 The first
step in the procedure is to vaporize a tunnel from an 11
o’clock to 1 o’clock position from the bladder neck
through to the verumontanum (Figures 4 and 5a). The
lateral lobes are then vaporized, paying regard to the
median lobe of the prostate (Figure 5b). The vaporization
is carried down to the apex, removing the apical tissue
while respecting the verumontanum (Figure 5c). The
median lobe is flattened (Figure 5d) and a midline
incision of the median lobe (or bladder neck) made,
which will avoid damage to the ureteral orifices
(Figure 5e). The remainder of the median lobe is then
removed by firing the laser from a medial to a lateral
position. Additional incisions will reveal the depth
necessary to reach the capsular fibres (Figure 5f). In the
final result, the solitary verumontanum is noted
(Figure 5g).
Bleeding
There is usually no clinically significant bleeding during
GreenLight laser prostatectomy. If bleeding does occur, it
is important not to panic as it is usually of minimal
clinical significance: some bleeding will occur during
almost any urinary endoscopy. The irrigation efficiency
of the 21–23 F laser cystoscope is much less than larger
The Basel technique. This technique starts with tunnelling at 5 o’clock and 7 o’clock down from the bladder
neck to the verumontanum. The lateral lobes are then
vaporized, starting from the tunnel upwards (for
example from 5 o’clock to 11 o’clock) to the level of the
surgical capsule. Subsequently, both the apex and the
anterior part of the prostate are vaporized. The median
lobe is always treated last as the fibre is more likely to
come into direct contact with the tissue and this increases
the risk of fibre degradation. Consequently, treating the
median lobe last avoids early fibre degradation, which is
of utmost importance with large prostates.
Finalizing the procedure. In deciding if sufficient tissue
has been removed, the bladder should be emptied and
the cavity that has been generated, viewed when it is not
under pressure. There should be a clear view towards the
bladder neck from the verumontanum with presentation
of a TURP-like cavity (Figure 6). Irregularities are
checked for as well as the integrity of the ureters. Any
bleeding is noted and dealt with. It should be noted that
Figure 4 The first stage in the anterior start technique: vaporization of a tunnel from an 11 o’clock to 1 o’clock position from the
bladder neck through to the verumontanum.
Prostate Cancer and Prostatic Diseases
Figure 5 The anterior start technique: (a) vaporization of a tunnel
from an 11 o’clock to 1 o’clock position from the bladder neck
through to the verumontanum; (b) vaporization of the lateral lobes;
(c) vaporization down to the apex; (d) flattening of the median lobe;
(e) midline incision made in the median lobe; (f) additional
incisions made at the bladder neck to identify the capsular fibres;
(g) solitary verumontanum revealed.
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321
Prostate volume (ml)
200
150
100
50
R-Quadrat linear = 0.24
0
0
100000 200000 300000 400000 500000 600000 700000
Energy (J)
Figure 6 The final cystoscope image following laser vaporization
of the prostate.
Figure 7 Scattergram depicting energy usage with the GreenLight
PV laser based on prostate size in patients treated at the University
of Basel.
resectoscopes, and even tiny bleeders can thus
obscure the vision. These are usually easily dealt with
by simply continuing the procedure; they should not
stop rapid tissue removal as long as visibility is
maintained. Specific strategies for dealing with troublesome bleeding points are usually only needed for very
large or very inflamed prostates, in which case a
stepwise strategy is adopted. Irrigation bag height
may be increased, or if an inflow–outflow pump is used,
the flow rate or pressure rate may be increased to
improve visibility. If the bleeder is difficult to coagulate,
it is useful to reduce the laser output power to 30 W and
to defocus the beam, thereby increasing the working
distance and generating coagulation of the tissue. If it is
difficult to access the source of bleeding, then tissue can
be ablated around the site first, but it is not recommended that any blood vessel be lasered directly as
vapour bubble formation occurs inside and this can open
up the vessel further. To get orientation and visibility, the
cystoscope is drawn back behind the verumontanum
with increased irrigation, but the laser fibre remains in
the prostatic fossa to treat the bleeding source. A small
bleed at the bladder neck often can be controlled with a
Foley catheter with a large balloon on traction. A more
significant arterial bleed should be managed by inserting
a suprapubic trocar with double inflow through the
scope and suprapubic outflow or a 5 mm laparoscopic
trocar, allowing a clear view to be obtained. Very rarely,
electrocautery or a resectoscope may be needed for
arterial bleeders.
Power usage
There are no limits to the amount of energy that is used
during a single procedure, but obviously larger prostates
require more energy. Although no hard-and-fast rule can
be given, general guidelines are that for a prostate sized
40 ml, the energy usage is of the order of 150 000 J; for a
50 ml prostate, the energy usage is 200 000 J and for
100 ml prostate, the energy requirement is over 350 000 J
(Figure 7). Also, beginners in the technique tend to use
power less efficiently and this needs to be taken into
account. More than one laser fibre may be required
during a single procedure when treating bigger glands. It
should be noted that fibres are for single patient use and
should not be reused.
Catheterization
For elective patients operated under general anaesthetic,
the need for a postoperative catheter is at the discretion
of the surgeon. If necessary, the duration is generally
short, from a few hours up to overnight. Longer
catheterization times may be preferred in patients with
urinary retention, with very large prostates, the elderly
and those on anticoagulants or those who fail the initial
voiding trial due to some swelling/inflammation around
the bladder neck or prostatic urethra.9
Training recommendations
For both trainees and trained urologists, we recommend
the following approach to case selection when learning
PVP. The first 10 patients should have prostates less than
50 g; these patients should not be in retention, have
prostatitis, a large median lobe or have undergone a
previous prostate procedure, for example TUNA or
microwave therapy. A formal audit on outcome is
recommended after the completion of the 10 cases. If
there have been any major complications or cases where
the patient is unable to void spontaneously, then a
further 10 cases are recommended and another audit
conducted on these cases. To achieve a sufficient
competence level, it appears that around 30–50 procedures should be conducted for most users. A surgeon
should be able to deliver 200 000 J/h before starting very
large glands. Although ‘wet labs’ and simulators are not
widely available, it seems sensible to look at developing
such facilities for those learning PVP in the future.
Urological trainees
It is recommended that training is conducted by trainers
from an accredited training centre. Local guidelines must
also apply. Training should be conducted under direct
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supervision and the trainee should be already experienced
in endoscopic techniques; previous experience of video
endoscopy is helpful. It is necessary to undertake a laser
safety course in most countries. Interestingly, experience
in the TURP procedure does not seem to provide much
benefit when learning PVP, and adaptation of the TURP
technique is not advised. However, surgeons who are
experienced with TURP tend to learn PVP more easily as
they are familiar with the anatomical landmarks.
Experienced urologists
For experienced urologists, it is strongly recommended
that they attend a formal training course and to have an
experienced mentor present at their first cases. Viewing a
PVP training video alone is not sufficient.
The new 120 W laser now coming into use will require
a similar level of technical knowledge to the 80-W laser
system. The handling of the 120-W laser is comparable
with the 80 W laser, but with the higher energy
application, tissue removal is likely to be increased.
Acknowledgements
This study was supported by an unrestricted educational
grant from Laserscope, CA, USA; Urology Research
Fund, King’s College, London, UK and Instituto de
Cirugı́a Urológica Avanzada, Madrid, Spain.
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