Mobile Kidney Stone Pulverisation - ESWL

History

During the eighties, enormous progress was made in the field of lithotripsy. The first lithotriptor was to be found in Rotterdam in the early eighties and consisted of a water bath in which patients reclined. The principle of lithotripsy lies in the generation of a shock wave in water which passes into the body in the form of a vibration and in this way breaks down or pulverises the kidney stone. At that time, the shock waves were generated by spark plugs. Since this pulverisation treatment was painful, patients were given epidural anaesthesia during treatment. Overtime, the tips of the spark plugs gradually burnt away resulting in an increasing gap between the spark plugs. This led to a stronger shock wave and caused more and more pain as the spark plugs wore out.

For a long time patients could only receive this treatment in Rotterdam. In the case of acute symptoms, the only alternative locations were Antwerp and Düsseldorf. “Patients poured into Rotterdam from all parts of the Netherlands. Consequently, this lithotriptor was only available for our patients to a very limited extent. Due to the [small] number of patients, purchase of a lithotriptor was not an option. So when the mobile lithotriptor came on the market in 1988, Gelre Hospitals decided on a managed services contract with the supplier” according to Dr De Vlaam. “Gelre Hospitals was one of the first users of the mobile kidney stone pulveriser. We started with a Donnier HM4 lithotriptor. The shock waves caused by this were rather intensive. Over the years, the technology has fortunately considerably improved.”

New technology

Gelre Hospitals is currently using the mobile Siemens Lithostar Multiline. This is more patient-friendly and no longer causes unnecessarily intensive shock waves.
“The equipment works by electromagnetic generation of shock waves, the so-called ESWL (Electromagnetic Shock Wave Lithotriptor),” Ms Scholtsz explains. ”The advantage of this is that the effectiveness and speed of the ESWL can be adjusted to provide a minimum of 1 million shots of a constant quality. Furthermore, the patient experiences less pain. The shock head is cone-shaped. The stone is positioned in the focus of the shock wave head (1 x 8 cm) to ensure maximum effect.”

“This generation of mobile lithotriptors offers a number of advantages,” Dr De Vlaam continues. “It means that no space is needed inside the hospital walls for a permanent lithotriptor, we don’t need to invest in this equipment, we don’t have to maintain or upgrade the equipment, and a specialised diagnostic technician from the supplier carries out the lithotripsy for us. We get comprehensive service and the logistic aspect is fantastic. The very fact that we could have a lithotriptor at our disposal here was therefore a gigantic step forward. The service is flexible: the lithotriptor is booked according to the required capacity.
There are firms which supply mobile lithotriptors that can be brought into the hospital, but then you need a room to be available. The mobile lithotriptor which we have been hiring now for eighteen years is installed in a trailer. The unit is parked just outside one of the hospital entrances and is easily accessible for our patients. The lift on the side of the trailer allows access by patients in wheelchairs or even complete stretchers.”
“Over the years, the technology has developed. Whereas we initially used to be able to treat only 4 patients in one morning, we can now treat 8. A constant level has now been reached with regard to the number of treatments. Since we clearly don’t need fulltime capacity, the mobile lithotriptor is therefore the perfect solution for us.”

Procedure for lithotripsy

“The patient lies on a special table,” Ms E. Scholtsz explains. “The table top has a large recess for the shock head. With the aid of a C-arm, the table is positioned in such a way that the stone to be treated is precisely in focus. There is a cross on the monitors with which the stone can be localised. Adjustment is done from two angles because it not only has to be focused on the X and Y axes, but also on the Z-axis. Adjustment is sometimes done using ultrasound. Following adjustment, the technician positions the shock head against the patient. The stone automatically remains in focus because the water in the water cushion in the undersection of the table top is increased or decreased. The shock waves are gradually increased to the desired intensity. The number of shots varies between 2,500 and 4,000. This depends on the equipment and the position of the stone. It is important for the positioning of the stone to be very precise, and bearing in mind that the stone is not always optimally visible, only an experienced eye can identify the stone in such situations.”
“A plain abdominal x-ray is important as a starting-point for the treatment. In the case of a ureteral stone, an IVP (ed.: intravenous pyelogram) may be important for evaluation since a small distal ureteral stone can easily be confused with a phlebolith (calcified tissue). The trend towards replacing an abdominal x-ray and IVP by a CT-scan can make it difficult for the clinician because they show stones which cannot be seen on x-rays.”
“If the stone is in the kidney, the strength of the shots needs careful adjustment. Because if the shots fired at a kidney stone are too strong, it could cause a haematoma. The result depends on the composition of the stone. Several treatments can be given without causing any problems for the patient. During lithotripsy, the patient may start to feel renal colic. A rib lying in the centre of the shot can also be painful. Experience has shown that there are ways of making the patient more comfortable if treatment is painful. This can be done for example by treating the stone from the front rather than the back.”
“It is very important to keep the patient under careful observation during treatment. In order to eliminate the pulverised stone particles from the body after treatment, the patient needs to drink plenty of liquid for a couple of weeks after treatment.”
“There are few contraindications. Extreme hypertension, due to temporary high blood pressure being caused, occurs very rarely. Patients taking anticoagulants should stop at least a week before treatment to avoid the risk of bleeding. Coagulation time should be normal. Pregnancy is also a contraindication.”

Treatment used to be – and sometimes still is – done by the urologist, but there are a number of radiodiagnostic technicians who are specialised in this treatment. Final responsibility lies with the urologist.

Pain

“The patient is given painkillers in the form of tablets or suppositories before treatment as sedation,” according to Dr De Vlaam.
The method of sedation differs from hospital to hospital. [Diclophenac 50 or 100 mg sub can also be given before the treatment.] Severe pain rarely occurs, but if necessary pethidine can be administered. Treatment lasts approximately 25-30 minutes.”
“As the stone breaks up, colicky cramp with nausea may be felt. In very rare cases, there may be fibrillation of the heart, resulting in the most extreme case in heart failure. Following treatment, there may be blood in the urine. Complications seldom occur.”
“In general, no more than 5% of patients experience pain during treatment. Only 1% experience such severe pain that treatment has to be stopped. In the case of severe cardiac stress, some symptoms are possible. It is interesting to note that pain can suddenly occur as the stone pulverises. Following this there is often blood in the urine because the ureteral wall or pyelum wall is slightly damaged. In the past, a patient used to stay in the hospital until he had urinated. If there was blood in the urine, he stayed a little longer. Patients were always given preventive antibiotics before the treatment. Nowadays we only do this if there is an increased risk of infection.”

Success rate for lithotripsy

“In the case of a non-invasive intervention, the success rate is 75%. It is sometimes difficult to assess whether treatment of patients by lithotripsy is successful,” Dr De Vlaam explains. “A great deal depends on the composition of the kidney stone. With pulverisation, it is essential for the particles to be thoroughly expelled. If the stone mainly consists of crystals, it will easily pulverise. But if there is calcium precipitate on the stone and calcium oxalate is formed, the pulverisation is more difficult due to the hard structure.”
“What is particularly interesting is when a lithotripsy appears to have had no effects but during the second treatment the stone completely disintegrates. It seems likely that something did probably occur during the first treatment. So we shouldn’t give up too quickly if a treatment doesn’t appear to work immediately.”
If no results can be seen after 3-4 pulverisation treatments, it is possible to opt for percutaneous nephrolithotomy whereby a needle is inserted into the kidney stones in the renal pelvis. If this is unsuccessful, surgery can be considered. However, this happens very rarely, for example in the case of a coral kidney. This is a kidney which is completely filled with coral-like stone. It is indeed very strange, but the patient does not necessarily even notice that he has a coral kidney. In the case of surgery, a transverse incision is made in the kidney or the kidney is cut open like a bread roll and in this way the coral-like calcium structure can be removed.”

After care

Before receiving treatment, patients are given a patient leaflet about lithotripsy. This states, for example, that if they suddenly develop a fever following the treatment, they should immediately contact the urologist. This is likely to be sepsis and may cause renal sepsis. Lithotripsy is carried out as a day treatment and is not stressful for patients. If the patient has no pain or other symptoms, no further check-ups or treatment are necessary.

Lithotripsy not suitable for bladder/gall stones

“In the eighties and nineties, endeavours were made to use the lithotripsy method to pulverise gall stones; but gall stones and bladder stones do not lend themselves to this type of treatment,” according to Dr De Vlaam. “Bile consists of a thickened substance but not water. This means that the gravel cannot be carried away. Obstructive stones are not pulverised either because of the risk of urosepsis.”
“Bladder stones are not pulverised because they are harder than kidney stones. They should preferably be removed endoscopically rather than invasively. If required, the stone can also be dealt with by means of lithotripsy via a ureter or the bladder.”

Conclusion

In recent years, pulverisation of kidney stones has become much less stressful for patients. Patients can usually go straight home after treatment.
The use of a mobile lithotriptor has many advantages for the hospital which hires the lithotriptor with the radiodiagnostic technician on board: no need to equip a permanent location, no investment in equipment, updates/upgrades are provided by the supplier of the units, likewise maintenance of the equipment, allowing the urologist more freedom.
New-style hospitals which aim for limited inpatient capacity, if temporarily short of capacity (renovation, replacement) or with waiting list problems, increasingly make use of mobile units, not only lithotriptors but also PET, CT, PET/CT and MRI scanners which form part of a modern strategy.

Author: Anne van der Zwaan, Marketing & Communication - Alliance Medical