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ESWL (extracorporeal shock wave lithotripsy)

Extracorporeal Shock Wave Lithotripsy (ESWL) is a non-invasive medical procedure used to break down kidney stones, negating the need for incisions or invasive surgical procedures. In this procedure, focused shock waves are transmitted from outside the body to target and fragment kidney stones, facilitating their natural passage through the urinary system.

The technology offers a significant advantage in reducing recovery time, potential complications, and discomfort for patients, making it the preferred method for treating certain kidney stones.

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Principle Behind ESWL

ESWL operates on a specific principle to fragment kidney stones, utilising focused shock waves, which are high-energy waves generated outside the body. These waves travel unimpeded through soft body tissues until they meet denser materials like kidney stones.

When the shock waves encounter the kidney stones, the energy carried by the waves is transferred to the stone, causing stresses that can crack and fragment it. This method ensures that the stone is broken down into smaller, sand-like particles. These smaller fragments can then be naturally passed out of the body through the urinary system without causing significant discomfort.

The accuracy of targeting is paramount. During the procedure, the kidney stones are often located in real-time using X-ray or ultrasound, ensuring that the shock waves are precisely focused on the stones and limiting potential damage to surrounding tissues.

Indications for ESWL

Size of Kidney Stones

ESWL is best suited for stones that are less than 20mm in diameter. Stones within this size range are more effectively and efficiently fragmented by the shock waves and are then more likely to pass naturally.

Location of Kidney Stones

Stones located in the upper or middle parts of the kidney (renal pelvis and upper calyces) respond particularly well to ESWL. Stones in the lower part can also be treated, but they might not pass as easily after the procedure.

Composition of Stones

ESWL is more effective for certain types of stones, particularly those composed of calcium oxalate, certain types of uric acid stones, and some less common stone types.

Preference over Other Treatments

ESWL might be chosen over other treatments in the following scenarios:

  • The patient prefers a non-invasive procedure
  • Previous success with ESWL for treating kidney stones
  • Contraindications for surgical interventions
  • The patient’s health status might not allow for more invasive procedures

The ESWL Procedure

Pre-procedure Preparations

  • Medical Assessment: The patient undergoes an assessment which includes a review of medical history, a physical examination, and imaging studies such as X-rays or ultrasound to determine the size and location of the kidney stone.
  • Fasting: Patients are usually advised to abstain from eating or drinking for several hours prior to the procedure.
  • Medication Review: Some medications, particularly blood thinners, may need to be temporarily discontinued to reduce the risk of bleeding.
  • Consent: An informed consent form, detailing the procedure’s benefits and risks, will need to be signed.

During the Procedure

  • Positioning: The patient is positioned on an operating table, either supine or prone, depending on the stone’s location.
  • Anaesthesia: Sedation or light anaesthesia is administered to ensure the patient remains still and to minimise discomfort.
  • Imaging: Real-time X-ray (fluoroscopy) or ultrasound is used to locate the kidney stone.
  • Delivery of Shock Waves: Once the stone is located, high-energy shock waves are targeted towards the stone. These waves pass through the skin and body tissues to reach the stone, fragmenting it into smaller pieces without causing significant damage to surrounding tissues.
  • Duration: The procedure typically takes between 45 minutes to an hour.

Post-procedure Care

  • Observation: Patients are observed for a short duration after the procedure to ensure there are no immediate complications.
  • Pain Management: Mild discomfort or pain may be experienced post-procedure. Analgesics are prescribed as needed.
  • Fluid Intake: Patients are encouraged to drink plenty of water to help flush out the fragmented stone particles.
  • Follow-up Imaging: An X-ray or ultrasound may be scheduled a few weeks after the procedure to ensure that all stone fragments have passed or to monitor any remaining fragments.
  • Instructions: Patients are informed about potential signs of complications, such as persistent pain, fever, or blood in the urine, and advised to seek medical attention if these occur.

Benefits of ESWL

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    Minimally Invasive Nature

    Unlike some other stone removal procedures, ESWL does not require incisions or invasive surgical techniques. The shock waves are directed from outside the body, targeting the stone without the need for any surgical intervention.

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    Recovery Time

    ESWL boasts a quicker recovery time compared to more invasive procedures. Most patients can resume their normal activities within a few days, and hospital stays, if required, are typically short.

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    Success Rates

    ESWL has proven effective for many patients, with high success rates in fragmenting stones of suitable size and density. When combined with increased fluid intake post-procedure, many patients can successfully pass the fragmented stones without the need for additional interventions.

Potential Complications and Risks

Side Effects

  • Blood in the urine: It’s common for patients to notice a light pink hue to their urine post-procedure due to the passage of stone fragments.
  • Bruising and pain: The skin over the treatment area might exhibit some bruising. Patients may also experience pain as stone fragments pass through the urinary tract.

Infection

Although infrequent, there is a risk of infection after the procedure. Symptoms to watch out for include fever, chills, and persistent pain.

Blockage

Fragments of the stone can occasionally block the ureter, causing pain and potentially leading to kidney damage.

Injury to the kidney or surrounding organs

The shock waves used in ESWL can cause minor damage to the kidney, which usually heals on its own. In rare cases, it may lead to more severe complications.

Incomplete stone fragmentation

ESWL might not break up larger stones completely. In such cases, additional treatments may be required.

Hypertension or diabetes

There’s some evidence suggesting a potential link between ESWL and the onset or worsening of hypertension and diabetes. However, the connection is not firmly established, and ongoing research aims to clarify these associations.

Post-Procedure Care

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    Hydration

    Drink ample water to help flush out stone fragments from the urinary system. Aim for 8-10 glasses daily unless advised otherwise by the doctor.

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    Pain Management

    Over-the-counter pain relievers, such as paracetamol or ibuprofen, can help manage discomfort. Always follow the recommended dosage and consult with a healthcare provider before starting any medication.

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    Monitoring

    Observe the urine for any blood, which might appear after the procedure. It should gradually decrease over a few days. Pass any collected stone fragments to the healthcare provider for analysis, which can aid in understanding the cause of stone formation and prevention strategies.

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    Activity Restrictions

    Light activities are typically permissible, but it's best to avoid strenuous exercises or heavy lifting for at least a week post-procedure.

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    Dietary Precautions

    Depending on the composition of the stones, dietary modifications might be advised. This can include limiting intake of specific foods or increasing consumption of others. It is recommended to reduce salt intake and maintain a balanced diet.

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    Avoiding Infections

    Notify the healthcare provider if symptoms like fever, chills, or persistent pain occur, as they may indicate an infection.

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    Follow-up Appointments

    A post-procedure ultrasound or X-ray may be scheduled within a few weeks of ESWL to assess the success of the treatment and ensure all stone fragments have passed. Attend all scheduled follow-up appointments to monitor for any complications and discuss any concerns with the urologist.

Comparison with Other Stone Removal Techniques

ESWL vs. Percutaneous Nephrolithotomy (PCNL)

ESWL:

  • Minimally invasive
  • Typically used for smaller stones
  • No incisions; shock waves break down stones externally

PCNL:

  • Invasive procedure requiring a small incision in the back
  • Suitable for larger stones or when ESWL isn’t effective
  • Directly extracts the stone through the incision, often quicker relief

ESWL vs. Ureteroscopy (URS)

ESWL:

  • External procedure; no instruments inserted
  • Suitable for stones in the kidney or upper ureter

URS:

  • A thin tube (ureteroscope) is passed through the urinary tract to the stone
  • Suitable for stones in the lower ureter
  • Stone is either retrieved or broken down using laser energy

ESWL vs. Open Surgery

ESWL:

  • Minimally invasive with fewer risks associated
  • Faster recovery time
  • Suitable for most stones, depending on size and location

Open Surgery:

  • Large incision made to directly access and remove the stone
  • Longer hospital stay and recovery period
  • Reserved for very large stones or complex situations where other methods might not be effective

Get an Accurate Diagnosis & Proper Treatment
for Your Urological Conditions

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Dr Lee Fang Jann image

Dr Lee is a urologist and kidney transplant surgeon with a broad-based expertise of all urological disorders

He has subspecialty focus on men’s health and male infertility, and special interest in minimally invasive prostate enlargement therapy and kidney stone treatment. Dr Lee has received numerous awards for service excellence such as the Service With A Heart Award (2006-2008, 2011) and the Singapore Health Quality Service Award (2016).

  • Bachelor of Medicine and Bachelor of Surgery (Singapore)
  • Membership of The Royal College of Surgeons (Edin)
  • Master of Medicine (Surgery) (Singapore)
  • Fellowship of the Academy of Medicine (Urology)
  • Clinical fellowship at Oxford Transplant Centre in the UK

Prior to entering private practice, Dr Lee served in the public sector for 16 years at SGH, where he initiated dedicated clinics evaluating and treating patients with complex men’s health and fertility issues. He also led the Renal Transplant Program and laparoscopic donor nephrectomy service as Surgical Director.

Apart from clinical work, Dr Lee is active in academia and believes in the importance of grooming the next generation of doctor. He was Senior Clinical Lecturer at NUS’ Yong Loo Lin School of Medicine and currently, Adjunct Assistant Professor at the Duke-NUS Medical School. Dr Lee is also regularly invited to share his experiences locally and regionally through lectures, workshops and surgical demonstrations.

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    Frequently Asked Questions

    Is ESWL painful?
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    While the procedure might cause some discomfort, pain relief is often provided. Some patients report a stinging sensation, but severe pain is uncommon.

    How soon can I return to work after ESWL?
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    Most patients can return to work within a few days. However, recovery time can vary depending on individual circumstances.

    Are there any long-term effects of ESWL?
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    ESWL is considered safe with a long track record of use. Rarely, there might be minor complications, but long-term adverse effects are uncommon.

    How effective is ESWL compared to other treatments?
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    ESWL is effective for many patients, especially for stones less than 20mm in diameter. However, the success rate can vary depending on the stone’s size, density, and location. Other treatments might be more suitable for larger or harder stones.

    Will my kidney stones come back after ESWL?
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    While ESWL addresses existing stones, it doesn’t prevent new ones from forming. It’s essential to understand the cause of the stones and make necessary dietary or lifestyle changes to reduce recurrence.