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Lithotripsy techniques

-Extracorporeal Shockwave Lithotripsy (ESWL)-TUL : TransUrethral Lithotripsy

-Laser lithotripsy-Electrohydrolic Lithotripter (EHL)-Pneumatic Lithotripters-Ultrasonic Lithotripsy

-Cystolithalopaxy forceps

ESWL - Introduction :

extracorporeal = from outside the body

shock waves focused on the stone

need for open surgery reduced to 1 - 2 %

Advantages of ESWL

Non invasive safe day case no pain no blood loss no convalescence periodCan use for all age groups

Disadvantages of ESWL

Relies on normal urine flow for clearance

may require retreatment

Successful ESWL Prerequisites

Absolute :functioning kidneys unobstructed passage Relative :stone size UTI

Efficacy after 3 months

large renal pelvic calculi ➡75% stone-free rate large lower calyx calculi ➡50% stone-free rate

small renal pelvic calculi ➡90% stone- free rate small lower calyx calculi ➡ 70% stone- free rate

Overall, approximately 75% of patients with renal calculi treated with ESWL become stone-free in 3 months

Extracorporeal Shock Waves Lithotripsy

• History of ESWL • How does ESWL work? • Indications • Complications • Optimizing ESWL • New Applications

History

Dornier - German Aircraft manufacturer

1980 - Human Model 1 ( HM1) - 1st patient

(First lithotripter used on human subject)

1984-ESWL approved by the FDA- HM 3 - 1st commercial lithotripter - Used in water tank - electrodes changed every 200 - 300 shock

C-arms for ESWL



Mechanism of Action

Shock waves- a special form of sound waves that have a sharp peak in positive pressure followed by a trailing negative wave

The change in density and acoustic impedance when traveling from water to stone results in fragmentation

Mechanism of Action

Compressive Force (Hold Stone)

Tensile ForceShearing ForceCompression F(Shockwaves)

Stone Disintegration

Method

2500 - 4500 shock waves (related to stone size)

Larger or Harder stones - retreatment gap 10 days

crushed stones pass in 0 days - 3 weeks

Technical Aspects

Energy Source (Shockwave generator)

Device to focus the shock wave

Coupling Medium

Stone Localization System

Methods producing Shock waves

Supersonic emitters : point source : electrical discharge with acoustic sonic boom

Electro Hydraulic Finite amplitude emitters : surface source :displacing a surface by electrical discharge

Electro Magnetic

Piezo Electric

Spark gap technology

Focusing systems

Coupling Medium:Water

water bathwater-filled drums or cushions

. Air bubbles entrapped

Stone Localization

Fluoroscopy U/S

Indications

Treatment of choice for : Ideal patient : non-obese, and have total stone

size<2.2cm (or volume of stone canbe regarded)

Renal/ureteric stonesBetter for uric acid stone

Other therapies should be considered if the overal stone burden is high (>2cm), in the presence of infection, with calcium oxalate monohydrate stones, impacted or lower pole stones, in obese patients

Contraindications

Absolute contraindications :1. Acute UTI or urosepsis2. Uncorrected bleeding disorders or

coagulopathies3. Pregnancy4. Uncorrected obstruction distal to the

stone5. AAA (Abdominal Aortic Aneurysm)6. RAC (Renal artery calcification)

Contraindications

Relative contraindications :1. Body habitus: Morbid obesity and orthopedic or

spinal deformities

2. Renal ectopy or malformations (eg, horseshoe kidneys and pelvic kidneys)

3. Complex intrarenal drainage (eg, infundibular stenosis)

4. Poorly controlled hypertension (due to increased bleeding risk)

Contraindications

Relative contraindications :5. Gastrointestinal disorders

(exacerbation after ESWL treatment in rare cases)

6. Renal insufficiency7. People with Cardiac Pace maker

Postoperative care

maintain activity to facilitate stone passage Fluid intake Follow-up for 2 week (KUB and renal

ultrasonography) Report severe pain resistant to IV or oral

medications Report fever



Complications of ESWL

Minor :Abdominal painhaematuria - 24 hrs to 1 week

Steinstrasse (street of stones) α stone size - obstruction + colics

Major (Dose dependent):perirenal haematoma : 0.66% - severe pain / Hb ⬇ - treatment conservative (+ blood transfusion)

- rarely nephrectomy

Complications of ESWL

Not proven :

HypertentionDiabetes melitus

Steinstrasse:[stīn′stra-se] is the German word for "stone street“ : Multiple small calculi are lined up in the distal left ureter (white oval)after extracorporeal shockwave lithotripsy had been performed in this patient. A ureteral stent hadbeen placed (black arrow) as a precautionary measure.



Optimizing ESWL

Stent (decrease renal colic and pain )

Tamsulosin (Flomax) ESWL shock rate

ESWL should be performed at 60-90 shocks/minute to achieve optimal stone fragmentation



New Applications for ESWL

Chronic Calcification like heel spur Pancreatic stone Gallstones Peyronie’s Disease Erectile Dysfunction

Heel spurs:

Knee pain:

Achilles tendon:

Tennis elbow:

Golf elbow:

Shoulder pain:

Hip pain:

Shin pain:

Tendons:

plantar fasciitis

patellar tendinitis

achillodynia

lateral epicondylitis

medial epicondylitis

tendinopathy

bursitis trochanterica

tibialis anterior synovitis

chronic enthesopathies

Painful trigger points

ESWT

Pain relief-Anti inflammatory- improve Healing-break down calsification deposites

ESWT has been shown to stimulate osteoblastsstimulate fibroblasts

Cause bone healing and bone union

healing of connective tissuesUsed For :Stress Fractures Avascular Necrosis Slow-healing bone (Delayed unions) Non-healing bone (Non-unions

ESWT also diminishes pain by:

Hyperstimulation anesthesia , short lived. "gate-control" mechanism, long lived

Contraindications for ESWT

presence of bone tumors certain metabolic bone conditions certain nerve or circulation disorders pregnant patients At open growth plate where an infection is present where gas or air is present in the body

Efficacy :

90% improvement for plantar fasciitis (Journal of Orthopedic Research, 2005)

91% improvement for calcific tendonitis (Journal of American Medical Association, 2003)

77% improvement for tennis elbow (Journal of Orthopedics, 2005)

RSWT (Radial Shockwave Therapy)

Devices with radial shockwaves. The energy is spread over a large surface area. These devices produce a low to medium energy level.Pneumatically generated shockwaves are introduced into the body over a large (radial) surface area by means of a freely movable hand piece. The therapeutic shockwave, which is generated in the hand piece, is introduced by the transmitter surface into the pain region to exert its curative effect.

PSWT (Planar Shockwave Therapy)

In considering the application of ESWT to wound care, the technology must be adapted into a wide focus treatment area. To generate planar shockwaves, the reflector utilized in the PSWT handpiece is made of a generalized parabolic reflector.The focal point of these plane waves is, by definition, "unfocused" or "defocused", meaning a focal point no longer exists. Therefore, the shockwave characteristics for the parabolic reflector could be defined as plane waves or, in other words, parallel ray. By this, the acoustic field stimulates a large area.

Refrence

1. Smith's General Urology-17th edition2. Shock Wave Physics for Urologists3. Extracorporeal Shock Wave Lithotripsy (Erin M. Burns, PGY-2 Medical University of South Carolina Department of Urology)

4. emedicine.medscape.com5. eswt.net/focused-shock-waves6. europeanurology.com7. urologymatch.com

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