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ESWL Revolution

History of the Shockwave Lithotripters

Ever since the first human application was performed on a Dornier prototype lithotripter (Human Model 1 = HM1) in 1980 and the first definitive kidney lithotripter (HM2) was installed in Munich in 1982, the extracorporeal shock wave lithotripsy has been rapidly propagated throughout the world revolutionizing urinary stone treatment. The Dornier HM3, the archetype of a first generation lithotripter, featured a large water bath for optimal shock wave coupling, fluoroscopic imaging, an ellipsoid reflector with a small aperture and a shockwave generator, necessitating general or spinal anesthesia.

More lithotripter manufacturers started their research and development activities after the introduction of HM3. About 20 or so lithotripters were developed between1985 and 1989 using either X-ray or ultrasound (but not both) for stone localization. The integration of a water-cushion-coupled shock wave generator in an X-ray table allowed multifunctional use of the stone machine and is considered as the key feature of a second generation lithotripter.

After 1990, most of the leading lithotripter companies developed new machines or modified their systems to comply with the following specifications (as the basic requirements for a third generation lithotripter):

  1. A combined localization system of ultrasound and fluoroscopy (only manual localization is required). 
  2. A wide range of energy output of the shock wave source (i.e. peak pressure) aiming at an efficacy.
  3. A larger aperture of the focusing system enabling treatment under minimal anesthesia.
  4. Integration of the shock wave source, the fluoroscopic unit and the ultrasound device.

Due to technology advancement in the past decade, several leading lithotripter developers have devoted additional development efforts in patient safety and treatment efficiency than what’s required for the third generation machine. Lite-Med Inc., as one of them, had come up with what may be called a “fourth generation lithotripter”.

Potential Damage to the Human Body from ESWL

  1. ESWL requires anesthesia
    Higher energy is used by ESWL in order to have shockwaves effectively break stones. The patient moves due to pain during the treatment which results in not correctly hitting the stones. Therefore, anesthesia is normally necessary for the ESWL procedure.
  2. Overdose of X-ray radiation exposure
    Traditional lithotripters only utilize X-ray to locate the stones. The X-ray is first turned on for stone localization before the treatment and then turned off as soon as the shockwave treatment starts. After applying about 300 shockwaves to the patient the X-ray is turned on again to locate the stone and adjust the target position in order to make sure the shockwave focus is correctly positioned at the stone during the treatment. About 3000 or more shockwaves are normally required in the ESWL procedure and, therefore, at least 10 X-ray exposures are given to the patient during the treatment. This may result in overdose of radiation to the patient and create other side-effects later.
  3. Damage to tissue adjacent to the stones
    The shockwave focus of traditional lithotripters is fixed at the target position after the initial localization and between adjacent re-localizations. The stones move following patient’s breath movements and, therefore, relocate away from the shockwave target position after each (re-)localization. In this condition, the target hit-rate reduces to one half or less from the original 100%. In other words, only  one half of the shockwave energy is transferred to the stones and the rest is absorbed by the neighboring tissues, Thus more damage to the kidney and other surrounding organs as shown in the next chart.

     

kidney1                     kidney2
Temporary Injuries
  • Local Bruise Under Skin
  • Pain Around Target Area
  • Hematuria
  • Perirenal Hematoma
  • Surrounding Organ Damages
Permanent Pathologic Changes
  • Fibrosis In the Damaged Area
  • Hypertension
  • Reduced Renal Function

 

New Technological Advancement of the 4th Generation ESWL

Lite-Med has developed a 4th generation ESWL machine with following advanced techniques to overcome drawbacks of traditional lithotripters:

  1. High Performance Shockwave Generation System
    With improved shockwave energy density the Lite-Med lithotripter can achieve high stone breaking efficiency at lower shockwave pressure. A kidney stone patient going through Lite-Med’s ESWL procedure can normally get effective shockwave treatment without any anesthesia or pain killers.

  2. Dual X-ray and Ultrasound Auto-Localization System
    With Lite-Med’s lithotripter, we only need to expose the stone patient with X-ray once at 0 degree and again at 30 degrees at the beginning of ESWL treatment. The computer will position the patient and the stone at the shockwave focus automatically. With the X-ray turned off and the ultrasound detector moved in to monitor stone movements continuously, the computer controlled lithotripter keeps on making corrections to the stone position according to ultrasound images of the stone without using X-ray. Thus, the entire ESWL procedure only requires X-ray localization to be done once and, therefore, very little radiation dose is given to the stone patient.
    1
  3. Ultrasound Stone Image Tracking and Locking System
    Utilizing the non-ionization characteristics of the ultrasound we can monitor  the stone fragmentation in progress during the entire ESWL procedure. Based on a method similar to the principle of target missile tracking, we can track stone movements during the treatment process. By guiding the shockwaves to the right stone location at the right time we can easily increase the stone hit-rate to 85%.
Comparison between Lite-Med’s Localization with Tracking and without Tracking
2 3

No Tracking:
Stone movement due to breathing may result in damage to kidney & adjacent organs during shockwave treatment ( Perirenal Hematoma, Severe Hematuria)

With Tracking:
Shockwave focus moves with the movement of the stone which results in high hit-rate and better fragmentation efficiency  (45%→86%)

During the ESWL treatment the stone normally moves in and out of a certain target window following the patient’s breath rhythm. Stone image locking is based on the rule of firing – that is to fire the shockwaves when the stone moves inside the target window and to stop firing the shockwaves when the stone moves outside the target window. With stone image locking, the stone hit-rate is, therefore, near 100%.

Advantages of Lite-Med Lithotripter’s Innovative Technologies

  • No anesthesia or analgesic is needed due to Lite-Med Lithotripter’s high efficiency shockwave creation. This means less cost in drugs and related material and less risk to the patient due to drug’s side effects.
  • Outpatient surgery can be carried out, without hospitalization.
  • Lite-Med’s patented stone tracking and locking systems produce better stone fragmentation and less tissue damage.
  • Ultrasound localization results in very low radiation dose and reduces the treatment risks through real-time monitoring.

Kidney Stone

According to the statistics: Up to 10% of Taiwanese population have had urinary tract stones, that is about one out of every 10 adults is a risk of urolithiasis problems. Therefore, we need to have some knowledge of the causes and prevention of urinary tract stones.

1.What are urinary tract stones?

Urine crystalline material, gathered into hard objects and stored in the urinary system, the kidneys, become the urinary tract stones. They can be classified according to the location of their existence kidney stones, renal pelvis stones, ureteral stones, bladder stones, prostate stones and urethral stones.

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2.Reasons for the formationof urinary tractstones

The cause of urolithiasis is very complex. Roughly speaking, as a variety of free ions in the urine concentration is too high, it results in crystalline precipitate formed stones. Usually it is associated with geographical location (Taiwan is located in the high incidence region of urolithiasis), season (summer has higher incidence), race (black has lower incidence), gender (men have higher incidence than women), age (30-50 years old get mostly), food, water (hard water), occupation and lifestyle (lack of proper exercise, overeating, sittingbehind the desk, heavy brain usage are more likely to get), urinary tract infection, genetic constitution, metabolic disorders, certain medications such as diuretics, aspirin, anti-gout drugs and drinking little water. These are closely related and a detailed assessment is necessary in order to know the cause or causes. Moreover, a variety of different components of the stone has some specific exception factors exist.

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3.Types ofurinary tract stones

Types of urinary calculi in Taiwan, may be roughly divided into three categories:

  1. Calcium oxalate and a small amount of calcium phosphate and calcium oxalate mixtures, the most common kind, accounting for about 70% of urinary tract stones.
  2. Calcium phosphate and magnesium ammonium phosphate getting bacterial infection in the urine and formed stones, accounting for about 15%.
  3. Organic compounds such as uric acid, uric acid salts, and cystine formed stones, accounting for about 15%.

4.Symptoms caused byurinary tract stones

  1. Kidneystones:
    • Renal colic: Originated in deep waist and may spread to the surrounding areas, the male downward spread to the testeswomen spread down to the bladder.
    • Hematuria.
    • Obstruction, renal edema may form.
    • Infection: chills, fever, bladder inflammation.
    • Nausea, vomiting, abdominal swelling.
    • Waist dull: dull pain ora feeling ofdiscreet.
    • Renal stones and staghorn calculi may be asymptomatic.
  2. Ureteral stones:
    • Ureteric colic, may spread to genitals and thighs.
    • Hematuria.
    • Hydronephrosis, hydroureter.
    • Cystitis (urgent and frequent urination, urination with burning sensation)
  3. Bladder stones:
    • Pain spread to the urethral.
    • Bladder discreet sense.
    • Intermittent urine flow, urinary tract obstruction.
    • Cystitis (bladder irritation, urinary pain and discomfort).
  4. Prostate stones:  No symptoms, often accompanied by benign prostatic hypertrophy (hyperplasia).
  5. Urinary tract stones:
    • Urethral mucosadamage.
    • Difficulty in urination.

5.How to diagnoseurinary tract stones

If you suspect any of the above symptoms occur to you, you may take the abdominal X-ray and routine urine check to determine whether you have "urinary tract stones." Renal ultrasound can detect relatively small or X-ray opaque stones, such as uric acid stones. It may also find out whether you have hydronephrosis or not.  Detailed X-ray photography of the urination system may further inform you the positions and sizes of stones, and whether they have caused urinary tract obstruction or not.

6.The treatment ofurinary tract stones

Methods of treatment for stone patients according to individual circumstances, stone location, size, hardness, having urinary tract obstruction or not, provide various options to choose from. Generally, about eighty percent of urinary tract stones can be treated by ESWL. Some large kidney stones, such as staghorns, using percutaneous renal lithotripsy is dominated. For ureteral stones, which usually cause severe hydronephrosis, ureteroscopy may be more appropriate. For bladder stones, cystoscopy lithotomy surgery is the most quick and thorough method for complete clearance of the stones.

  1. Non-invasiveExtracorporeal ShockWave Lithotripsy (ESWL)
  2. Slight invasiveUreteroscopy lithotripsy / Bladder lithotripsy / PerCutaneous Nephrolithotomy Lithotripsy (PCNL)
  3. InvasiveKidney stone surgery cut / Lithotomy renal pelvis surgery / Amputated kidney surgery / Intraoperative ureteral lithotomy / Lithotomy surgery

All in all, thanks to the modern technological advances, the vast majority of urinary tract stones, may have ESWL and endoscopic lithotripsy to treat. Aside from special circumstances, surgery to remove stones, at this time has been rarely used.

7. How to prevent the occurrence of urinary tract stones

  • Drink plenty of water, do not hold back pee

Do not hold back pee, drink more and pee more can help quickly excrete bacteria, carcinogenic substances and easy stone-forming substances, reducing opportunities for kidney and bladder damage. If a person’s body does not have water drinking restriction he should drink daily 3,000-4,000 C.C. and evenly distributed throughout the day, such as drinking hourly 200C.C. This is the only way to prevent the occurrence or recurrence of stones. Drinking plenty of water should be evenly distributed daily in time, rather than concentrated in a certain period of time with a lot of water and with little or no water in other periods. Do increase the water intake in hot weather, fever, diarrhea, and after exercise.

  • Drink lessbeer

Some people think that beer can be a diuretic to prevent the occurrence of urinary tract stones. On the contrary, the wort in brewing beer contains calcium, oxalic acid, and other acidic substances like ukrainiannucleotides and purine nucleotide. Their interaction can increase the body's uric acid and become an important factor to promote the formation of kidney stones.

  • Eat less meat and animalorgans

Control meat and animal organs intake; because metabolism of meat produces uric acid. Animal organsis a high-purine foods. Catabolism of animal organs also produces high blood uric acid, which is an ingredient to form uric acid stones. Therefore, the daily diet should be mainly vegetariandiet and eat more fiber-rich foods.

  • Eat less salt

Salty diet will increase the workload of the kidneys. Salt and calcium have a synergistic effectin vivo and can interfere with the prevention and treatment of kidney stone drug’s metabolic processes. Daily salt intake should be less than five grams.

  • Eat spinach with caution

According to statistics, more than 90 percent of the stones contain calcium, and calcium oxalate stones account for about 87.5%. If the food intake of calcium oxalate salt is too high, and the calcium oxalate in the urine is supersaturated, the excess calcium oxalate crystals precipitated from the urine may possibly form stones. Spinach is one of the vegetables people eat often and it also contains the highest oxalate in foods.

  • Do not drink milk before bedtime

Milk is rich in calcium and the majority of stones contain calcium. The most dangerous factor in stone formation is the concentration of calcium in the urine increases suddenly in a short period of time. The peak excretion period of calcium through the kidneys is about 2 to 3 hours after drinking milk. If the body is in sleeping state during this time, the urine is more concentrated and more calcium passing through the kidneys, it is easy to form stones.

  • Not to take more sugar

After taking sugar the concentration of calcium, oxalic acid, and the urine acidity will all increase in the urine. Increase in uric acid makes uric acid calcium, calcium oxalate precipitate easily and promote stone formation.

  • Eat dinner early

The peak calcium excretion time is usually about 4 to 5 hours after the meal. If a person eats his dinner too late, he will be sleeping in bed during the peak calcium excretion time. Then his urine which can’t be excreted is retained in the ureter, bladder, urethra, and urinary tract, resulting in increased urinary calcium. It can easily precipitate into small crystals and, over time, expand gradually to form stones.

  • Eat more vegetables and fruits

Vegetables and fruits contain vitamin B1 and vitamin C, and their final metabolites in the body are alkaline. Uric acid is readily soluble in alkaline urine. It is, therefore, beneficial in the treatment and prevention of stones.

  • Reduce protein intake

Studies have shown that a high protein diet can increase the incidence of urinary stones, so moderation in food proteins, especially animal protein, for all patients with stones are beneficial.

8.Variety of stonesdiet points

A. Calcium oxalate stones

Reduce oxalate:

  • Try not to eat foods high in oxalate, such as: tea, coffee ... and etc. (Note 1)
  • Avoid excessive intake of vitamin C.
  • Increased intake of vitamin B6  (Please follow your physician’s instructions).

Lower calcium:

  • Avoid excessive intake of vitamin D.
  • Avoid drinking hard water.
  • When cooking bone soup, do not add vinegarOtherwise, calcium in the bone will dissolve in soup.
  • Limit foods high in calcium: milk, cheese, ice cream, yogurt, cheese cakes.
  • Reducing salt intake, eat light.

B. Calcium phosphate stones

  • Eat less foods high in phosphorus, for example: yeast, mushrooms and etc. (Note 2)
  • Reduce calcium intake. (See above)

C. Magnesium ammonium phosphate stones

 

  • Take acidicdiet.(Note 3)
  • Control occurrence of Infection.

 

D. Uric acid stones

  • Take alkaline diet. (Note 4)
  • Take uric acid reduction drugs according to your doctor.
  • Take low-purine diet. (Note 5)
  • Restrict alcohol intake.

E. Cystinecalculi

  • Limiting protein intake, such as: meat, poultry, fish, eggs, soybeans, peanuts, and wheat.
  • Take alkaline diet. (Note 4)
  • Drink fruit juice (grapefruit juice, orange juice, cranberry juice, and grape juice).

 

Note 1.  Foods high inoxalic acid content:

Tea, black tea, coconut, coffee, cola, beer, cranberry juice, lemon, hyacinth beans, spinach, citrus, grapes, apples, tomatoes, Philippine vegetables, rhubarb, beets, okra, sweet potatoes, figs, plums, plums, strawberries, almonds, chocolate, cocoa, peanuts, lettuce, celery, radishes, asparagus.

Note 2.  Foods high inphosphorus content:

Yeast, wheat germ, shrimp, mushrooms, whole grains, cereals, offal, egg yolks, milk, beans, nuts, cocoa, chocolate, fruit juice powder.

Note 3.  Acidic diet

Protein, meat, poultry, fish, cereals, grapes, watermelon, tomatoes, corn, asparagus, processed fruits, olives, plums, cranberries, pumpkin.

Note 4. Alkaline diet:

Milk, vegetables (especially pods and green vegetables), most fruits, kelp, seaweed, halibut, salmon, trout, beef.

Note 5.  High purine content diet:

Marine fish (anchovy fish, dried fish, sardines), offal (heart, liver, kidney, brain, spleen, intestine), gravy, meat soup, sausage, mushrooms, asparagus, beans, yeast category (Yakult, fermented milk, JanSu/vitamin candy), chicken, scallops, clams, shrimp, mussels, sprouted beans, seaweed. These foods should be avoided.

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