Renal Stones

The diagnosis of kidney stones inevitably raises the question as to which therapy will work best in your specific case. Today, there are various invasive and non-invasive procedures to choose from according to the type of stone and the specific stone location in the kidneys or ureter.

Consult your doctor and jointly decide on the right treatment for your specific needs. The individual procedures not only differ in terms of their invasiveness and anaesthesia requirements, but also with respect to the rapidity of stone clearance and to the surgical risks they may involve.

The following information is not intended to anticipate your doctor's in-depth advice, but rather to give you some basic understanding of the methods to be discussed in more detail with your physician.

Available therapy options

Except for special cases and taking into account the patient's individual requirements, renal calculosis can generally be treated with one of the following four therapy methods:

• Extracorporeal shock wave lithotripsy (SWL): stones are disintegrated by extracorporeally applied shock waves without causing skin lesions.
• Percutaneous stone removal (PCNL): a tube-shaped access tract is made through the skin into the kidney to allow direct access to the stones by means of forceps and other instruments for extraction by grasping or for fragmentation and flushing.
• Endourological stone treatment: stones are removed by inserting an endoscope into the urinary tract.
• Open surgery: stone removal by open surgery is only required in exceptional cases.

Extracorporeal shock wave lithotripsy (SWL)

- A breakthrough in stone therapy -

Extracorporeal shock wave lithotripsy (SWL) is the least aggressive stone treatment method. This therapy option was first used on human patients in 1980 and has rapidly become the method of choice in the treatment of the most diverse types of calculosis.

- Non-invasive procedure – no skin lesions -

Acoustic shock waves are generated extracorporeally in a water cushion and then introduced into the body without causing any skin lesions. They are focused in the focal zone and targeted at the stone at a high energy level. The application of several thousand shocks causes the stone to break apart into sand-like granular fragments which are flushed out of the kidney or ureter naturally during urination. Hospital stays are short or not necessary at all, provided that the stone fragments are passed without any problems.

- Gentle on the patient -

Extracorporeal shock wave lithotripsy is a very gentle therapy procedure because, in most cases, it can be performed without general anaesthesia and merely requires the administration of an analgesic agent. SWL has hardly any side effects. Occasionally, failure to discontinue medication affecting coagulation early enough may cause in less than 1% of cases haematomas¹, which, however, can be easily controlled.

- Natural passage of stone fragments -

In rare cases, the passage of the stone fragments may be associated with painful colics. These can be treated with medication or by means of a simple ureter stent. The lithotripsy procedure can be repeated in case of an insufficient degree of stone fragmentation. The SWL technique is simple and safe to perform.

- Avoiding invasive procedures -

All in all, extracorporeal shock wave lithotripsy seems to be the best choice for almost all types of calculosis. However, there are some stones that are rather difficult to disintegrate with shock waves. In these cases, two or three treatment sessions may be necessary to eliminate the stone. However, this is usually unproblematic since SWL is easily repeatable. In other cases, the stone to be fragmented may be extremely large so that multiple therapy sessions are required. In such cases, there is a risk of the pulverized stone fragments temporarily blocking the ureter so that measures need to be taken to ensure normal urine passage. Still, this is a minor procedure which can be performed on an outpatient basis.

Today, SWL is performed with state-of-the-art lithotripsy devices that ensure an extremely gentle yet effective treatment.

Percutaneous stone removal (PCNL)

- Direct access to the kidney -

In cases in which rather large stones need to be disintegrated, a small incision should be made in the patient's back to gain direct access to the kidney. Contrary to open surgery, this procedure is only minimally invasive. Still, it is more complex than SWL since it requires anaesthesia and the use of various instruments to crush the stone inside the kidney.

- The tunnel to the stone -

The incision made in the back is necessary to create a thin tract to the kidney under X-ray or ultrasound control. This tract is gradually dilated until instruments with a diameter of several millimetres can be introduced into the kidney. As side effects, bleedings requiring transfusion are reported in 5 – 12% of cases1. Provided that this procedure is performed correctly and professionally, even large stones located in the renal calices can be disintegrated in a single session. Sometimes, however, small stone fragments may still be present in the calices. Occasionally, such residual fragments need to be treated by SWL (see information above) in a second session.

Endourological stone treatment

Reaching the kidney throughnatural body passage -

Endourological stone treatment is less invasive than PCNL but still more complicated than extracorporeal shock wave lithotripsy. In cases in which small stones have moved down from the kidney into the ureter, thin and lately flexible instruments can be inserted into the ureter through the urethra and bladder, that is through natural openings and without requiring any incision in the skin. Using suitable instruments such as small forceps, the stones can be removed by grasping and extraction.

- Stone fragmentation -

If stone removal through the narrow tracts is difficult or impossible, the stone can be crushed inside the ureter by means of fiber optic laser light and then sucked off. As side effects, 8-17% perforations of ureters are reported1. Occasionally, this method even allows stones in easily accessible renal calices to be crushed and the stone fragments to be removed.

- Rapid stone clearance -

Endourological stone treatment is usually performed under general anaesthesia. Another benefit offered by this technique is that, in most cases, complete stone clearance is achieved in a single session. However, it should be mentioned that both percutaneous stone removal (see above) and stone treatment by means of flexible endoscopes entail certain risks and may occasionally cause side effects such as bleeding or ureteral constriction. However, such side effects can be easily controlled.

Choosing the right therapy

- A difficult choice -

Despite their complexity and the higher risks they involve, percutaneous stone removal (PCNL) and endourological stone treatment with flexible endoscopes, in particular, have become increasingly popular among surgeons for a variety of reasons. One of them is the immediate stone clearance achieved in a single session. By contrast, extracorporeal shock wave therapy is said to frequently require re-treatment. This may be true, but, as outlined above, re-treatment is generally less aggressive for the patient than the described invasive therapy options.

- High success rates -

Especially in the treatment of ureteral stones, SWL is a strong alternative to endourological stone therapy. It is important to know that complete stone clearance can be achieved in up to 97% of all patients treated with SWL and that in 73% of these cases only a single therapy session is required.²

The doctor of your choice will help you choose the right stone therapy for your specific needs. In individual cases, the rapidity of stone clearance will be given top priority, irrespective of the complexity or aggressiveness of the therapy. However, in all other cases the following principle should be adopted:

Why choose an invasive procedure when there is a non-invasive alternative?

This principle clearly speaks in favour of SWL.

After all, most cases of calculosis around the world are treated with extracorporeal shock wave lithotripsy, whereas endourological therapy and PCNL together are used much less frequently. However, this does not speak against these techniques. In fact, they are performed with great success in cases in which SWL reaches its limits.

STORZ MEDICAL's contribution to enhancing the success rates of extracorporeal shock wave lithotripsy

- Even more effective and convenient -

As outlined above, shock wave therapy stands out from other techniques due to its minimally invasive nature and the few risks associated with it. The only significant reason why SWL, despite its suitability, may not be chosen as the initial treatment procedure in stone therapy is the uncertainty as to whether the patient will be completely stone-free and able to return to his/her normal environment immediately or shortly after the treatment session. The natural passage of the stone fragments may take several weeks. In the majority of cases, however, the stones are fragmented effectively and the fragments are passed without any problems.

Consequently, the objective must be to achieve an optimum degree of fragmentation and to improve and accelerate stone passage by suitable measures, such as drinking plenty of fluids, physical activity, etc.

Just like doctors and patients, we as manufacturers of shock wave systems have to contribute to achieving this objective.

What is so special about the STORZ MEDICAL lithotripter?

- Gentle and effective – no contradiction! -

With its patented shock wave source, STORZ MEDICAL has significantly increased the efficiency of shock wave lithotripsy whilst keeping the therapy gentle on the patient. The STORZ MEDICAL shock wave source, which is still second to none in the world of lithotripsy, has an exceptionally large coupling surface. The shock wave energy is distributed over the large surface at low pressure, thus causing hardly any pain in the sensitive skin area. It is only when the shock wave energy reaches the target region, the so-called focal zone, that it is bundled to an extent just sufficient to crush kidney stones. This ensures effective fragmentation without compromising the gentle nature of the therapy. Moreover, the precise location of the calculus is monitored by means of X-ray fluoroscopy or ultrasound imaging to make sure that the shock wave energy is precisely targeted at the stone to be removed.

What the doctor can do to increase the therapy success

- Maximum targeting precision -

In addition to taking general medical precautions to avoid complications or risks during shock wave lithotripsy, the doctor can contribute to the therapy success by targeting the shock wave energy at the stone with maximum precision and minimal loss. Obviously, only the amount of energy that actually reaches the stone can contribute to its fragmentation. As mentioned above, the shock waves are generated extracorporeally in a water cushion and then introduced into the patient's body.

However, shock waves can only produce the desired effects in the target area if they are not blocked off at the entry point by obstacles such as air bubbles. Shock wave transmission to the stone may also be interfered with by obstacles inside the body. Depending on the stone location, such obstacles include pelvic bones, rips or gas-filled intestinal sections. Based on his/her anatomical knowledge, the doctor has to determine the ideal shock wave access route to the stone.

- Reliable monitoring of target area and shock wave path -

This is exactly where some of the key features of the STORZ MEDICAL shock wave source prove their worth. In fact, the "in-line localization" feature allows the shock wave route inside the body to be precisely controlled during the therapy since localization and target area imaging take place through the source and thus in the direction in which the shock waves propagate. This enables reliable monitoring of the target area and shock wave path.

- Target missed? No problem! -

To answer a frequently asked question: individual shock waves that miss the target area (owing to respiration-induced kidney movements) do not present any hazard to the patient. In fact, one of the special features of shock waves is that their fragmentation effectiveness is highest when applied to hard and brittle materials such as kidney stones, whilst elastic soft tissue, such as muscles, renal tissue and the skin, remains unaffected. Still, needless to say, only the shock waves that actually hit the stone can contribute to the fragmentation success.

- What to do in case of insufficient stone fragmentation? -

Owing to the minimal aggressiveness of extracorporeal shock wave therapy for the patient, re-treatment is possible without any problems if, despite all care and efforts, the degree of fragmentation proves insufficient.

- Experienced doctors -

Since extracorporeal shock wave therapy entails hardly any risks, this technique no longer represents a difficult challenge for doctors. The general notion is that the doctor's skills and abilities only play a minor role when a powerful system is used for stone fragmentation by extracorporeal lithotripsy. Still, effective stone fragmentation requires careful therapy planning and preparation.

Things you can do to ensure rapid passage of stone fragments

- Plenty of fluids and physical activity -

Contrary to the invasive treatment options described above, extracorporeal shock wave therapy crushes the stones into granular fragments, which need to be passed out of the body naturally during urination. We recommend that you drink plenty of fluids so that the stone fragments are flushed out more quickly. Any kind of physical activity, such as climbing stairs, jumping, etc., will help loosen residual stone fragments in the renal calices and near the entrance to the bladder and flush them out.

These are some simple measures you can take to contribute to the success of SWL therapy and to achieve complete stone clearance.

STORZ MEDICAL uses its over 20 years of experience in shock wave therapy to eliminate your stones gently and effectively and to continuously improve its SWL systems by implementing state-of-the-art technology.