Geert G. Tailly, M.D.,1 Joost A. Baert, M.D.,1K. Robert Hente, M.D.,1 and Thomas O. Tailly, M.D.2
Summary
【Objective】 Since 1987, we have used five different models of DORNIER lithotripsy machines to treat urinary tract stones in various parts. The treatment effect of the various types of lithotripsy machines used is evaluated regularly and periodically to adjust the treatment strategy to achieve better results. Not all patients treated with this type of lithotripsy were included in the evaluation of each type of lithotripsy. This report retrospectively compares the evaluation results of various lithotripters during this period, aiming to explore the impact of different models of lithotripters and different shock wave sources on clinical efficacy.
【Materials and Methods】From September 1987 to September 2006, a total of 3079 patients were treated in our center. There are two types of stone crushers: hydraulic and electric stone crushers and electromagnetic stone crushers. Among them, the hydraulic and electric stone crushers are mainly HM4 (1987-1988) and MPL9000 (1988-1994), and the electromagnetic stone crushers are mainly Compact (1991-1999), DoLi U/50 (1996-1999) and DoLi S (1999-2006). Parameters assessed included location and size of stones, retreatment rate, adjuvant therapy, stone removal rate, and efficiency quotient (EQ).
【Result】 There was no significant difference in stone size and stone removal rate among patients treated with different types of lithotripsy machines (P=0.475). However, there were significant differences in the adjuvant rate and retreatment rate of various types of lithotripsy treatment. In terms of the pre-treatment rate, overall treatment rate and retreatment rate of ESWL, the DoLi S lithotripsy equipped with the EMSE 220F-XXP system was significantly better than that of other lithotripters (p<0.05, p<0.05 and p=0.0024). At the same time, the efficiency quotient of the stone crusher is gradually improved with the continuous improvement of the stone crusher.
【Conclusion】 Although the rate of stone clearing (85%-88.8%) has not changed significantly in the past 20 years, the efficiency quotient has been improving. This is largely attributable to the reduction in adjuvant and retreatment rates. The former is the result of improved treatment strategies and experience, while the latter is undoubtedly due to improvements in the source of the shock wave.
Foreword
Urolithiasis has been a very common disease in humans since ancient times. Surgical treatment of urinary tract stones has been around for centuries. Until the advent of endoluminology, surgery remained the mainstay of treatment for urolithiasis.
On February 7, 1980, Christian Chaussy treated a patient with stones for the first time with the DORNIER Lithotripsy Machine (HM3), following extensive experiments with shock waves in 1974.1,2,3 From 1980 to the autumn of 1983, only the Urology Clinical Center of the Grosshadern Hospital in Munich used a shock wave lithotripsy.
October 1983, Urology Center, Katharinen Hospital, Stuttgart (Director: F. A. Murphy) Eisenberger introduces the world's second lithocrusher (Human Body Type 3 or HM3). In March 1984, the Methodist Hospital in Indianapolis was the first to introduce a lithotripsy machine in the United States (James E. Lingeman and Daniel M. Newman). Subsequently, extracorporeal shock wave lithotripsy machines were quickly promoted in the world, and the treatment of urinary tract stones was fundamentally changed, and ESWL became the preferred treatment for most urinary stones. In 1987, the first stone crusher was installed in our center. By 2007, we had used 5 models of stone crushers.
Although we have not seen an increase in the rate of stone removal over the years, we have observed that the efficiency quotient is gradually increasing as the rate of adjuvant treatment and retreatment rate continues to decrease. The improvement of treatment strategies and the accumulation of experience are also the reasons for the improvement of efficacy, but the important role of the improvement of shock wave source cannot be denied.
While there has been little progress in shockwave lithotripsy since the introduction of the DORNIER HM3 lithotripsy machine, which is still considered the gold standard in ESWL, we believe that extracorporeal shockwave lithotripsy continues to advance, even if only in small steps.
Materials and methods
Since 1987, we have continuously retrospectively evaluated 3079 lithotripsy patients using both hydroelectric and electromagnetic lithotripters. Parameters assessed included stone location and size, as well as retreatment rate, adjuvant therapy, stone removal rate, and efficiency quotient. Table 1 presents the technical data of the various types of stone crushers in chronological order.
Both the DORNIER HM4 and the MPL9000X have a hydroelectric (spark gap) shock wave source. Underwater, spark plugs with two opposing electrodes are placed at the first focal point (F1) of the elliptical reflector. The capacitor connected to the spark plug is used for charging, and when charged to the maximum voltage, it suddenly discharges, causing an underwater electric spark to explode, causing the water around the electrode to evaporate suddenly, causing the release of a spherical shock wave and creating a reflection on the inner wall of the elliptical reflector, and finally focusing on the second focal point 4 (F2) of the elliptical reflector.
This process causes the temperature to be too high, which has an erosive effect on the electrodes, causing the electrical sparks and shock waves generated by the electrodes to be disturbed. Because the electrodes are quickly eroded, the spark plug life is limited, resulting in less than a few thousand shockwaves emitted. In addition, electrode erosion during treatment can lead to multifaceted changes in impact characteristics5.
The DORNIER Compact and DORNIER Lithrotripter series (DoLi U/15/50 and DoLi S) are electromagnetic crushers. The capacitor of an electromagnetic shock wave generator is connected to a flat copper coil, and when it is charged to its maximum, it suddenly discharges to generate an electromagnetic field. The electromagnetic field pushes the elastic copper film covering the copper coil, causing it to vibrate, resulting in the generation of shock waves in the water. Finally, the shock wave is focused by an acoustic lens at the treatment site6.
The electromagnetic shock wave is very stable and highly repeatable. In any energy range, an electromagnetic shock wave source can generate 2 million shock waves of consistent quality5.
All lithotripters use an inflatable balloon as a coupling. Over the years, the treatment strategy has not changed, mainly the existing imaging system of different lithotripters.
Imaging systems play an important role in precise positioning, treatment monitoring, and their treatment outcomes.
In contrast to the DORNIER HM3, the DORNIER HM4 has a bottom-mounted dual X-ray tube system. The DORNIER MPL9000–X, on the other hand, has dual ultrasound probes, one with a built-in probe within the treatment head and the other with a mobile X-ray C-arm. X-ray positioning requires a special electrode that extends the depth of treatment from 12 mm to 15 mm, which also changes the geometry of the focal spot.
Our early DORNIER Compact lithotripsy used a lateral isotopic center ultrasound probe and a mobile C-arm. However, the use of mobile x-rays for C-arm positioning is quite complex, resulting in the inability to use x-rays in conjunction with x-rays for localization (the treatment end is consistent with the patient). The latest DORNIER Compact lithotripters use a lateral isocentric or built-in ultrasound probe and integrate an X-ray C-arm. Although ultrasound and x-rays cannot be used simultaneously, they can be used in combination.
All DORNIER lithotripsy machines (DoLi U/15/50 and DoLi S) integrate an X-ray C-arm and a lateral axis ultrasound probe, allowing simultaneous use of both positioning imaging systems.
As long as imaging permits, ureteral stones can be treated in situ and retreated according to the algorithm in Figure 17-11. For patients who need to be hospitalized for acute renal colic due to ureteral stones, we also treat patients with emergency ESWL.12-15
There are two levels of pain caused by the shock wave: superficial pain at the skin level and deep visceral pain at the kidney level. Pain correlates with the energy level of the shock wave, lithotripsy, and relapse rate.
A variety of methods are currently recommended for pain relief, such as general anesthesia, epidural, intravenous anesthesia, local anesthesia (topical anesthetic), or no anesthesia.
Since 1987, we have used three different methods of pain relief (Table 2). Since 1996, our hospital has been using a PCA-device to continuously administer a mixture of affenanide and propofol through the vein, which is a safe and reliable method. Patients tolerate and cooperate well, side effects are minimal, and patients are able to recover and ambulate quickly after surgery16.
During the treatment of the patient, the DORNIER HM4 lithotripsy uses an electrocardiogram trigger. Other lithotripters did not use ECG triggering: from 1988 to 2002, 120 beats per minute, and from 2002 onwards, 80 beats per minute17.
Tables 3 and 4 provide an overview of the location and size of the stones treated by different lithotripters, respectively.
The effectiveness of the crusher is measured by its efficiency quotient.
Efficiency Quotient (EQ) =
Stone clearing rate
100%+ retreatment rate + auxiliary treatment rate after lithotripsy
The Efficiency Quotient (EQA) is a definition originally proposed by Denstedt, Clayman, and Preminger18 and incorporates the rate of stone clearing, retreatment, and adjunct treatment after ESWL.
The Extended Efficiency Quotient (EQB)19 takes into account all adjuvant rates, both preoperative and postoperative adjuvant therapy for ESWL.
Extended Efficiency Quotient (EQB) =
Stone clearing rate
100% + retreatment rate + pre-lithotripsy adjuvant rate + post-lithotripsy adjuvant rate
The Modified Efficiency Quotient 19 (EQmod) further distinguishes between treatment and adjunctive methods after lithotripsy
改良的效率商19(EQmod)=
Stone removal rate - therapeutic auxiliary rate
100% + retreatment rate + pre-lithotripsy auxiliary rate + post-lithotripsy auxiliary rate
In our study, we used the "Scaled Efficiency Quotient".
Results
In this study, we evaluated 3079 patients treated with 5 different types of dornier lithotripters. Since all patients are from the same group, we do not believe that there is a clear difference in the demographic data (age distribution, gender) of patients treated by each type of lithotripsy. Therefore, it can be assumed that all kinds of lithotripsy machines treat the same population. Nowadays, obesity and morbid obesity are increasing, and it is necessary to record their BMI because this may affect the lithotripsy effect. The incidence of this condition is on the rise, and prospective assessment of its impact on treatment outcomes will be of concern.
The results of the treatment of stones at all sites are shown in Table 5, while the detailed ancillary measures before and after each lithotripsy treatment are listed in Table 6. The therapeutic effects of ureteral stones and all adjunct measures used (Dornier MPL9000X, Dornier U/50, Dornier Lithotripter S) are shown in Tables 7 and 8, respectively. In addition to these differences, we did not group further according to the location of the stones. There was no significant difference in stone size.
The purpose of this retrospective study was to assess whether the overall efficacy of the centre progressed with the lithotripter. While further investigation is undoubtedly meaningful, further grouping by stone size is beyond the scope of this study. The overall stone removal rate (all stones) ranged from 85% to 88.8%. There was no significant difference between the different groups (P=0.475): there was no significant change in the stone clearing rate in the past two decades.
The dornier S with the EMSE220-XXP system had a significantly lower retreatment rate than other lithotripters (Table 9, p=0.0024), and its pre-crushing and overall lithotripsy rates were also lower than those of other lithotripters (Table 9, p<0.05 and P<0.05). The early series of lithotripsy machines (HM4, MPL9000X and Compact 1992) often required the stone to be pushed into the kidney before lithotripsy, and more patients needed to have a stent placed in front of the lithotripsy. The primary adjunct to any serial ESWL is ureteroscopy.
The Extended Efficiency Quotient (EQB) of the crusher has been gradually increased from 55 for the DORNIER HM4 to 70 for the EMSE220F-XXP DORNIER Lithotripter S. However, there was no significant difference in the stone removal rate of ureteral stones between the groups.
In terms of relapse rate, the EMSE220-XXP type was significantly better than the MPL 9000X type (p<0.001) and the Dornier U/50 type (p=0.0255), but there was no significant difference compared with the EMSE220-XP type (p=0.9597) (Table 10). In terms of adjuvant treatment rate (overall: pre+post-ESWL), EMSE220-XXP type was significantly lower than that of MPL9000X type (p=0.0002), Dornier U/50 type (p=0.0209), and EMSE220-XP type (p=0.0094) (Table 10). The Extended Efficiency Quotient (EQB) for the treatment of ureteral stones increased from 66.0 for MPL 9000X to 80.0 for EMSE220-XP.
Among the complications caused by the treatment of kidney stones by various types of lithotripsy, gross hematuria is the most common (80% to 90%). However, gross hematuria is less common (10% to 20%) in the treatment of ureteral stones.
The incidence of perirenal hematoma or subcapsular hematoma ranged from 0.2% to 0.3% throughout the study, with no difference among lithotripters. Stone Street is an infrequent occurrence and rarely attracts attention. We did not record its incidence.
Discussion
We evaluate the therapeutic effect of lithotripters by calculating the Extended Efficiency Quotient (EQB), which is a standard way to evaluate and compare the performance of lithotripters. However, in addition to the quantitative parameters in the formula, some non-quantitative parameters also play an important role in the performance and efficiency quotient of the lithotripter: such as the type of shock wave source, imaging mode and mass, stone load, stone incarceration, pain relief method, operator experience, and the frequency of the shock wave (Figure 2).
In this study, the Extended Efficiency Quotient (EQB) gradually increased from 4 for the Dornier HM50 to 70 for the DoLi S with the EMSE220-XXP system as the crusher improved. We also confirmed that the Extended Efficiency Quotient (EQB) for the treatment of ureteral stones increased from 66.0 for the MPL 9000X Dornier Lithotripsy to 80.0 for the DoLi S Lithotripsy with the EMSE220-XXP system.
Our experience has shown that the efficiency quotient of the new electromagnetic shock wave source crusher is higher than that of the DORNIER HM3 (Table 11). According to the data provided by the manufacturer (Table 12), the effective energy (Eeff) provided by the EMSE 220F-XXP is higher than that of the Dornier U/15/50 with the standard EMSE 220F system and the Dornier Lithotripter S with the more powerful EMSE 220F-XP system at each energy level setting. The effective energy (Eeff) of the EMSE220F-XXP type at the highest energy level was significantly higher than that of the unmodified Dornier HM3 type.
Effective energy (Eeff) is the energy of the shock wave pulse acting on an area of 12 mm Ø in the focal plane where it is in contact with the stone.
The EMSE 220F-XXP has the lowest total energy (4.7 J) required to completely crush standard artificial stones with a diameter of 12 mm among the DORNIER series of stone crushers, which is comparable to the unmodified DORNIER HM3 (4.2 J) (Table 12). At either power setting, the EMSE 220F-XXP model is superior to the unmodified DORNIER HM3 type in terms of disintegration capacity in crushing standard artificial stones with a diameter of 12 mm (Figure 3).
Lithotripters equipped with newer electromagnetic shock wave sources, such as the EMSE 220F-XXP, are at least as technically and better than the originally unmodified DORNIER HM3 in terms of technology and crushing quality. In addition to the difference in the source of the shock wave, the biggest difference between the two is the difference in the image system. The existing imaging and positioning methods of lithotripsy machine have a large impact on the treatment strategy of ESWL.
In general, x-ray imaging is mainly used to locate opaque stones throughout the urinary tract, while ultrasound imaging can be used to locate translucent and opaque stones in the kidneys (renal pelvis and calyces) as well as specific parts of the ureters (ureteronephrogenic junction, very proximal or distal ureters, the latter using the bladder as a sound window).
The HM4 lithotripsy machine is equipped with two fixed under-mounted X-ray tubes, which can theoretically locate opaque stones throughout the urinary tract. The application of a special positioning technology allows the lithotripsy to locate the distal ureteral stones in situ. However, this positioning system is unable to locate ureteral stones that overlap the sacroiliac joint in situ. This explains why most patients need to push the stone back into the kidney before lithotripsy.
The dual-positioning lithotripsy machine (DORNIER MPL9000X and DORNIER Compact) with integrated ultrasound and mobile X-ray C-arm can use ultrasound or X-ray to locate stones, respectively. Ultrasound is used to locate the kidney, the entire very proximal and very distal ureteral stones, and x-rays are used to locate most ureteral stones.
The DORNIER MPL9000X model can be localized using a combination of x-ray and ultrasound, but not simultaneously. The combination of x-ray imaging allows the lithotripsy machine to perform in situ ESWL for ureteral stones. The DORNIER MPL 9000 starter is only equipped with a dual probe positioning system. Subsequently, a mobile X-ray C-arm (MPL 9000X) was added. Prior to the improvement, this type of lithotripsy was only able to localize very proximal and distal ureteral stones in situ. As a result, most of the stones located in the ureters were still pushed into the kidneys before lithotripsy was given.
The original Compact type (1992-1996) was only able to use the ultrasonic positioning system in the joint positioning system. Its X-ray positioning system cannot be used in practice, making this series of lithotripters unable to treat ureteral stones in situ. The new Compact lithotripter is now capable of using a combination of X-ray and ultrasound to locate stones.
DORNIER lithotripsy machines (U/15/50 and S) combine ultrasound and X-ray positioning systems to provide maximum imaging and positioning capabilities. The DORNIER S is the only lithotripsy machine that can be positioned simultaneously with a built-in ultrasound and X-ray.
Precise positioning and careful real-time monitoring can lead to better stone crushing results and reduced retreatment rates. At the same time, the multi-purpose imaging and positioning methods also affect the adjuvant treatment rate.
The observations suggest that there is no change in the rate of stone clearing, which may be attributed to the fact that the anatomy of the urinary tract may be the most important factor influencing the rate of stone clearing, in addition to the burden of stones20-21. The more complex the anatomy of the renal calyceal system, the less likely it is that the stone will be completely removed. It is an indisputable fact that the lower the lower the calyces, the more difficult it is to remove the lithotripsy.22-29
It is claimed that the new stone crusher is often less effective than the unmodified DORNIER HM3 stone crusher. Lack of training and experience can be a significant reason for the so-called "less effective stone crusher". The operators of the original DORNIER HM3 stone crusher were well trained before they were allowed to operate. In addition, in the early days, due to the small number of lithotripters, there were many patients treated at the lithotripsy center. As more manufacturers produce cheap stone crushers, more and more stone crushing centers introduce more stone machines, but the number of patients treated in these centers is limited.
Manufacturers and operators often assume that crushers can be "plugged in" with little to no proper operating training. Extracorporeal lithotripsy techniques are despised in many lithotripsy centers, often performed by junior residents, who receive little or no training in this area and are replaced by more training in open and endovascular surgery. So, this in itself can lead to serious complications.
Stone crusher manufacturers and many stone centers must pay attention to the proper operation training of stone crushers. There is no doubt that this will greatly improve the lithotripsy effect and reduce the occurrence of complications. Here, we expect all lithotripter operators to have theoretical knowledge of the fundamental physics of shock waves30.
Conclusions
Although the clear rate has not changed significantly in the past 20 years, the Efficiency Quotient (EQB) has gradually increased with the continuous improvement of the crusher. This was mainly due to the reduction in the rate of adjuvant and relapse. The former is the result of improved treatment strategies and experience, while the latter is undoubtedly due to improvements in the source of the shock wave.
The DORNIER lithotripter S lithotripter with the EMSE 220F-XXP system has an overall efficiency quotient (EQB) of 70 for the treatment of stones in all parts of the urinary tract, which is higher than any other lithotripter of any other type available today. In vivo and in vitro experiments, it is also more effective than the unmodified DORNIER HM3 lithotripter, which has been the "gold standard" for ESWL.
There is no doubt that the DORNIER HM3 stone crushing was set to a high standard from the start, but the crusher with the new electromagnetic shock wave source is at least as good as the former, if not better.
Other advantages, such as the consistent quality of the shock wave source, the possible absence of general or spinal anesthesia for treatment, lower operating costs, dual-use built-in X-ray and ultrasound simultaneous positioning, and improvements in versatile and multidisciplinary technology, have allowed the newer electromagnetic lithotripsy machines to do more in the treatment of all stones.
