History of extracorporeal shock wave lithotripsy (ESWL).
As early as 1966 an engineer at Dornier Systems, an aircraft manufacturer in Friedrichshafen (West Germany), accidentally discovered the effect of shockwaves on human tissue. Since 1963 Dornier Systems had been conducting experiments on shock waves originating from high velocity impacts on aircraft.
In 1974 extensive clinical research, supported by a grant of the German federal government, was started in co-operation between Dornier Systems, the Urologic Clinic (Prof. E. Schmiedt) and the Institute for Surgical Research (Prof. W. Brendel) of the Ludwig Maximillians University in Munich, West Germany (1,2,3).
Following these extensive experiments the first human treatment was performed by Christian Chaussy with a Dornier kidney lithotriptor (Human Model 1 or HM1) on February 7, 1980 (4,5).From this date on until fall 1983 extracorporeal shock wave lithotripsy was performed exclusively at the Urologic Clinic of the Grosshadern Hospital in Munich.
In October 1983 the second lithotriptor worldwide (Human Model 3 or HM3) was installed in the Department of Urology (Director : F. Eisenberger) of the Katharinen Hospital in Stuttgart. In March 1984 the first lithotriptor in the United States was installed at the Methodist Hospital in Indianapolis (James E. Lingeman and Daniel M. Newman).
Since then extracorporeal shock wave lithotripsy has been rapidly propagated throughout the world revolutionizing urinary stone treatment and making ESWL the primary mode of treatment for most urinary calculi.
Evolution of machine design.
Traditionally lithotriptors have been categorized as first-, second- or third generation devices( 6,7,8).
As the first lithotriptor marketed worldwide the Dornier HM3 can be considered the archetype of a first-generation lithotriptor.It features a large water bath for optimal shock wave coupling, fluoroscopic imaging, an ellipsoid reflector with a small aperture and an 80 nF-generator, necessitating general or spinal anesthesia. Multifunctional or multidisciplinary use is impossible.
Second generation lithotriptors feature an electrohydraulic, electromagnetic or piezoelectric shock wave source. Coupling is provided by a water cushion or partial water bath. The machines are further equipped with either ultrasonic or fluoroscopic imaging and can be operated anesthesia free. Limited multifunctional and / or multidisciplinary use are possible. The Dornier HM4, Dornier MFL 5000 and Dornier MPL9000 can be considered second-generation lithotriptors.
Third generation lithotriptors are equipped with a combined targeting system consisting of fluoroscopy and ultrasound to be used alternately or, in the ideal situation, simultaneously. They can be operated anesthesia free and the integration of both fluoroscopy and ultrasound in an endourologic treatment table allow multifunctional and multidisciplinary use.The Dornier MFL 5000U, the Dornier Compact-series and the Dornier Lithotripter (U/15/50 and S) and the Dornier Gemini can be considered third-generation devices.
Electrohydraulic and electromagnetic shock wave generation in Dornier lithotriptors.
The first Dornier lithotriptor, the Dornier HM3, was equipped with an electrohydraulic shock wave source (spark gap). Subsequently the Dornier HM4, the Dornier MFL 5000 and the Dornier MPL9000 featured electrohydraulic or spark gap shock wave sources.
Under water, a spark plug with two opposing electrode tips is positioned in the first focus (F1) of an ellipsoid reflector. A capacitor connected to the spark plug is charged to maximal voltage and then abruptly discharged causing the explosive formation of an underwater plasma channel and resulting in the rapid evaporization of the water surrounding the electrode tips. This releases a spherical shock wave that is reflected by the walls of the ellipsoid reflector towards the second focus (F2) of the ellipsoid reflector (9).
The thermal overload of this process causes an erosion of the electrode tips leading to irregularities in the resulting spark and the shock wave originating from it. A rapid erosion of the electrode tips thus limitates the life time of the spark plug to a couple of thousand shocks per spark plug.
The Dornier Compact-series and the Dornier Lithrotripter (U/15/50 and S) and the Dornier Gemini feature electromagnetic shock wave sources.
In electromagnetic shock wave generation a capacitor connected to a flat copper coil is charged to maximal voltage and abruptly discharged. This creates a magnetic field which repels a flexible copper membrane covering the copper coil resulting in the creation of a shock wave in the water in which the whole system is immersed. The shock wave is then focused into the therapeutic focus by means of an acoustic lens (10).
Electromagnetic shock waves are extremely constant in quality and reproducible. An electromagnetic shock wave source can produce up to two million shock waves of consistent quality.
Imaging systems in lithotriptors.
Treatment strategies in ESWL are to a great extent influenced by the imaging system available in a lithotriptor. Early lithotriptors were equipped either with ultrasound or fluoroscopy.In order to meet all the challenges in modern integrated stone management present day lithotriptors have to be equipped with both imaging modalities.
The ideal modern lithotriptor offers simultaneous use of both ultrasound and fluoroscopy. With the Dornier Lithotripter U/15/50 and the Dornier Lithotripter S and the Dornier Gemini we use ultrasonic targeting in 61.2% of cases, fluoroscopic targeting in 33 % and both modalities in 5.8 % (11).
Table I- 1 displays the advantages and disadvantages of ultrasonic and fluoroscopic targeting in ESWL while Table I – 2 displays advantages and disadvantages of an inline or an outline scanner in ultrasonic targeting.
|• in situ treatment of ureteral stones in all parts of the ureter• shorter learning curve||• easy targeting of radiolucent stones• easier targeting of smaller renal stones• real-time image : easier and faster adaptation of focusing• no exposure to radiation|
|• no direct targeting of radiolucent stones• small stones sometimes difficult to locate• no real-time image• exposure to radiation||• in situ treatment of ureteral stones is possible only for very proximal and very distal ureteral calculi• longer learning curve|
|Table I-1 Advantages and disadvantages of ultrasonic and fluoroscopic targeting in ESWL.|
|IN-LINE SCANNER||OUT-LINE SCANNER|
|• easier dissociation between multiple stones• easier targeting of very proximal and very distal ureteral stones• in the shock wave path||• for kidney stones the most appropriate window can be chosen : avoid ribshadows• better appraisal of fragmentation• use as diagnostic scanner• can be exchanged for 5 MHz scanner : children• far better image quality|
|• ribshadows may hide stones from view• poorer image quality• negative effect on shock wave power• possible damage of scanner by SW||• very proximal ureteral stones sometimes more difficult to find• more difficult patient positioning for prevesical stones|
|Table I – 2 Advantages and disadvantages of the use of an in-line or out-line scanner in ultrasonic targeting in ESWL.|
Results with Lithotriptors
The performance of a lithotriptor generally is measured by its
EFFECTIVENESS QUOTIENT (EQ) :
% Stone free patients
100% + % Re-treatment + % Aux. Proc.
The EQ as originally defined by Denstedt, Clayman and Preminger (EQ A ) (18) takes into account only the auxiliary procedures after ESWL. However, as auxiliary (endoscopic) procedures performed prior to ESWL also have the purpose to enhance treatment results, we think these pre-ESWL procedures should be included in calculating the Effectiveness Quotient (EQ B ). This EQ B is described as the “EXTENDED” Effectiveness Quotient.
Apart form this modification in the calculation of the EQ, one must also be aware of the fact, that a number of “hidden” parameters also play an important role in the EQ : imaging, treatment strategies, analgesia regimen, operator experience,...
A comparison of the EQ's of electrohydraulic, electromagnetic and piezoelectric machines of all manufacturers is given in Table II-1, Table II-2 and Table II-3 respectively.All EQ's are EQ B ‘s unless otherwise stated : the EQ's marked with an asterisk are EQ A 's.
Is there an improvement in the performance of lithotriptors ?When we consider the EQ's of most systems currently available, we see that the newer electromagnetic machines (Compact, Dornier Lithotripter S) score equally good and even better than the Dornier HM3. The EQ's of piezoelectric machines are generally low and not at all in the range of electrohydraulic or electromagnetic machines.The results with the new EMSE 220F-XXP (Dornier Lithotripter S) are among the best to date and seem to finally contradict the myth of “the spark gap supremary”.
The improvement in EQ's over the years (11) proves that ESWL treatments have become more effective. This is attributable to several factors : machine related (smaller focus, improved imaging with better targeting), patient related (decrease in average stone size) and operator related (better treatment strategies, greater experience).
Added advantages, such as the possibility of treatment without general or spinal anaesthesia, the lower running costs, the decreased exposure to X-rays and the improved multifunctional and multidisciplinary use, make the newer electromagnetic lithotriptors more versatile instruments, not only in overall stone management, but also in extracorporeal shock wave treatment (ESWT) of non-urologic ailments.
|ELECTROHYDRAULIC Machines : DORNIER|
|DORNIER HM3||Frick et al (19)Tiselius et al (20)Lingeman et al (21)Cass (22)Politis et al (23)Cole et al (24)Tiselius et al (25)Selli et al (26)Danuser et al (27)Erturk et al (28)Cass (29)Kishimoto et al (30)||25476735656247446265335|
|Distal ureteral stones in situMid-ureteral stones in situLower ureteral calculi in situUreteral stonesDistal ureteral stonesUreteral calculi|
|DORNIER HM3 mod||Puppo et al (31)May et al (32)Rassweiler et al (33)||646953||Lower pole renal calculi|
|DORNIER HM4||Tailly (34)Dickinson et al (35)Bierkens et al (36)||553838|
|DORNIER MFL5000||Graf et al (37)Gnanapragasam et al (38)Watson et al (39)Fuselier et al (40)||52524255||Ureteral calculiUreteral calculi|
|DORNIER MPL 9000||Tailly (41)Talati et al (42)Ohshima et al (43)||534857|
|DORNIER MPL 9000X||Tailly (41)||62|
|Table II-1 : Effectiveness Quotients of Dornier electrohydraulic lithotriptors.|
|ELECTROMAGNETIC Machines : ALL|
|DORNIER COMPACT||Tailly (1992) (44)Tailly (1996) (44)||6564||EMSE 140AEMSE 140A|
|DORNIER LITHOTRIPTER (USA)||Fuselier et al (40)||41||EMSE 140A (!)|
|DORNIER LITHOTRIPTER U/50||Tailly (11)||69||EMSE 220|
|DORNIER LITHOTRIPTER S||Tailly (15)TAILLY (present series)TAILLY (present series)||74.071.477.8||EMSE F150-P / Ureteral stones in situEMSE 220 F-XXPRenal & ureteral stones in situEMSE 220-XXPUreteral stones in situ|
|STORZ MODULITH SL20||Rassweiler et al (49)Liston et al (50)||6558|
|SIEMENSLITHOSTAR||El-Damanhouri et al (51)Clayman et al (52)Andersen et al (53)Netto et al (54)Mobley et al (55)Bierkens et al (36)||435631594631|
|Table II-2 : Effectiveness Quotients of electromagnetic lithotriptors (all manufacturers).|
|PIEZOELECTRIC Machines : ALL|
|WOLF PIEZOLITH 2200||Rassweiler et al (33)Bowsher et al (56)Marberger et al (57)||413050|
|WOLF PIEZOLITH 2300||Bierkens et al (36)Cope et al (58)||2848|
|EDAP LT.01||Tan et al (59)Kiely et al (60)||4146*|
|Table II-3 : Effectiveness Quotients of piezoelectric lithotriptors (all manufacturers).|
The ideal lithotriptor
Since its first introduction as a dedicated urinary stone crusher in 1980, the lithotriptor not only revolutionized urinary stone management but also conquered a significant role in concepts of “Integrated Endourology”.
Mostly due to improved imaging modalities indications for extracorporeal shock wave treatment of urinary calculi at all levels of the urinary tract have expanded.Shock wave sources have improved to deliver more power without however increasing the complication rate.
Already in an early stage of lithotriptor development, machines became “dry” using a water cushion instead of a water bath for coupling greatly simplifying handling of the machines.
Patient's comfort was considerably improved when general or spinal anesthesia could be abandoned in favour of sedoanalgesia, making ambulatory treatments possible.
Most manufacturers now also try to construct machines for multifunctional (Endourology) and multidisciplinary use (ESWT). The extracorporeal shock wave treatment (ESWT) of non- urologic ailments, such as pseudarthrosis, tendinosis calcarea of the shoulder, tennis elbow, heelspur, ... indeed seems to gain momentum.
The “ideal” lithotriptor should therefore offer:
- a shock wave source with large aperture : due to lower running costs, easier handling and excellent results an electromagnetic source seems preferable
- simultaneous use of both fluoroscopy and ultrasound
- incorporation of SW-source and imaging in a system suitable for endourologic treatments
- anesthesia free treatments : ambulatory treatments both in ESWL and ESWT
Ideally this lithotriptor is installed in a large EndoUrology suite equipped with a full range of endoscopic equipment and disposables for endourologic procedures.Dedicated endourologic nursing staff should complement the “hardware”, further improving efficiency and quality.
Non-stone applications in extracorporeal schockwaves: ESWT
Most of the non-stone applications of ESWT are notoriously problematic for any but the more invasive forms of treatment.
Attractive advantages of ESWT:
- Ambulatory treatment
- No or minimal side-effects
- Good results in the accepted indications
- Does not jeopardize the subsequent performance of other forms of treatment
ESWT in orthopedics
- Tendinosis Calcarea of the Shoulder (TCS)
- Medial and Lateral Humeral Epicondylitis (Tennis Elbow, …)
- Plantar and Dorsal Heelspur
- Point-of-attachment tendinoses:
- Patellar apex syndrome (Jumper's knee)
- Tendinopathies of the thoracic girdle
- Tendinosis in the greater femoral trochanter region
- Adductor strain in the pelvis
- Miscellaneous indications:
- Osteochondrosis (M. Osgood-Schlatter, M. Köhler, M. Perthes)
- Osteochondrosis dissecans (knee/talus)
- Pain from loosened cement-free protheses
1. Tendinosis calcarea of the shoulder (TCS)
Tendinosis calcarea of the shoulder is a very common, extremely painful condition of the shoulder leading to impairment of function and occasionaly complete shoulder stiffness (= “frozen shoulder”).
Most often calcium deposits are found in the tendon insertion of the supraspinatus muscle (51-88%) and / or the infraspinatus muscle (19-45 %).
Calcium deposits in the tendons of the m. supraspinatus and / or m. infraspinatus cause impairment of mechanical function and pain, leading to complete shoulder stiffness (“Frozen shoulder”).
b. Mechanism of action of ESWT
The mechanism of action of ESWT in TCS is not clear. Either through DIRECT action (cavitation) or INDIRECT action (improved vascularisation) the SW lead to resorption of the calcium deposits and thus to decrease of pain and improvement of function.
The ESWT of tendinosis calcarea yields a success rate of approximately 70 %.
d. Other types of treatment
D 1 . “CONSERVATIVE “ TREATMENTS
- Systemic antiphologistics
- Local injection of steroids
- Physiotherapy: temporary effect (Harmon 1958)
- TENS (Trancutaneous Electric Nerve Stimulation):improvement of pain in 10/11 pts (Kanda 1984)
- Laser (IR: ? placebo-effect (Gusetti 1989)
- Needling: Harmon 1958: 79 % good results (n = 400)
Da Palma 1961: 61 % good results (n= 136)
Gärtner 1993: 70 % resorption in Type 2
33 % resorption in Type 3
D 2 . SURGERY
|SUBACROMIAL DECOMPRESSION AND REMOVAL OF THE CALCIUM DEPOSITS|
|OPEN||E. Van Holsbeek et al.||Good or excellent: 81.1 %Patient satisfaction: 94.3 %|
|ARTHROSCOPIC||• Van Holsbeek et al.Harvard EllmanJames C. Esch et al.||Good or excellent: 83.1 %Patient satisfaction: 94.3 %Good or excellent: 88 %Good or excellent: 82 %|
2. Pseudarthrosis = non-union of fractures
Good results with ESWT (up to 70 % cure rate) are also seen in delayed union of fractures.
As in the treatment of TCS, the mechanism of action is unclear.Repeated sessions (3-6) are necessary.
ESWT in Peyronie's disease
Peyronie's disease is an affliction of the penis characterised by fibrous plaques in the tunica albuginea, the elastic sheath around the corpora cavernosa.This causes painful erections, angulation of the penis and ultimately erectile dysfunction.
Peyronie's disease is seen in approximately 1% of adult males, most common between the ages of 45 and 60.
Some 30 % of patients with Peyronie's disease will also develop contractures in the hand (Dupuytren's disease) or the foot.
2. Pathogenesis and risk factors
The exact cause of Peyronie's disease is as yet unclear.Some factors may play a role:
- (micro-)trauma: trauma with penile lesion, extreme sexual activity, invasive procedures on the penis, …
- genetic factors
- auto-immune factors
- inflammatory (vascular) factors
Peyronie's desease is characterised by the development of fibrous plaques in the tunica albuginea, the resistant, but elastic sheath around the corpora cavernosa.These plaques, which may also calcify in the process, impair the elasticity of the corpora cavernosa giving rise to:
- pain, spontaneously and / or upon erection
- indentations over the penile shaft
- angulation during erection --> problems during intercourse
- poor quality of erections
- erectile dysfunction
One or more of the above symptoms are indicative of Peyronie's disease.The fibrous plaques may be palpated during clinical examination.Ultrasound will give a good outline of the plaques and eventual calcifications
Multiple treatment modalities have been proposed:
A lot of medications have been prescribed with varying (mostly disappointing) results:
- Vitamin E
- Different chemotherapeutic drugs
c. Radiotherapy: should be considered obsolete
In most cases surgery will be the final resort:
- excision of the fibrous plaque
- plication of the tunica albuginea opposite the plaque: Nesbitt's procedure
- penile prosthesis
Since some time various centers have used extracorporeal shockwaves in the treatment of Peyronie's disease.
The method of action is not completely understood.Results however are encouraging:
- Beneficial effect on PAIN: close to a 100 % of patients become painfree.
- Improvement of angulation in 30 - 40 %.
- Better effect in non-calcified plaques.
- Improvement of quality of erections.
- Multiple sessions needed (3 - 10).
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