Extracorporeal Shock Wave Lithotripsy (ESWL)

Extracorporeal Shock Wave Lithotripsy, commonly abbreviated as ESWL, is a medical procedure that employs shock waves to break down kidney stones into smaller fragments, enabling their easy passage through the urinary tract. This non-invasive technique represents a significant advancement in the treatment of nephrolithiasis, offering patients an alternative to more invasive surgical procedures.

The Evolution of ESWL

The development of ESWL dates back to the early 1980s when it was first introduced as a revolutionary method for kidney stone management. Prior to ESWL, the primary treatment options for kidney stones were limited to open surgery or percutaneous nephrolithotomy, both of which carried significant risks and required extended recovery periods. ESWL quickly gained popularity due to its minimally invasive nature, reduced recovery time, and high success rates.

Mechanism of Action

ESWL works by generating shock waves outside the body, which are then focused onto the kidney stone using imaging guidance such as X-rays or ultrasound. These shock waves pass harmlessly through the skin and tissues, converging at the stone and causing it to fragment into smaller, more manageable pieces. Over time, these fragments are naturally expelled from the body through the urine.

Shock Wave Generation

The shock waves used in ESWL are typically generated by one of three main methods: electrohydraulic, electromagnetic, or piezoelectric. Each method has its own advantages and is chosen based on specific patient and stone characteristics.

Electrohydraulic Generation: This method uses an underwater spark to create shock waves. It is the original technique used in ESWL and remains effective, although it has been largely supplanted by newer technologies.

Electromagnetic Generation: This approach relies on an electromagnetic coil to produce shock waves. It is known for its precision and control, making it a popular choice in modern ESWL devices.

Piezoelectric Generation: Utilizing piezoelectric crystals, this method produces shock waves in a highly focused manner. It is considered the most advanced and least traumatic option for patients.

Procedure and Patient Experience

ESWL is usually performed on an outpatient basis, meaning patients can return home the same day. The procedure typically lasts between 45 minutes to an hour, depending on the size and number of stones being treated.

Preparation

Prior to the procedure, patients may undergo blood tests, urine tests, and imaging studies to determine the exact size, location, and composition of the kidney stones. They may be advised to avoid certain medications and to fast for a few hours before the procedure.

During the Procedure

Patients are positioned on a specialized table equipped with a water cushion or coupling gel to facilitate the transmission of shock waves. Sedation or anesthesia is often administered to ensure comfort and minimize pain. The medical team uses imaging guidance to accurately target the kidney stone and deliver the shock waves.

Post-Procedure

After ESWL, patients are typically monitored for a short period before being discharged. They are instructed to drink plenty of fluids to help flush out the stone fragments and may be given pain medication to alleviate discomfort. Follow-up appointments are scheduled to assess the effectiveness of the treatment and to monitor for any potential complications.

Success Rates and Complications

ESWL boasts a high success rate, with approximately 70-90% of patients achieving stone-free status after a single session. However, success can vary based on factors such as stone size, location, and composition. Some patients may require additional ESWL sessions or alternative treatments if the initial procedure is not fully effective.

Common Complications

While ESWL is generally safe, it is not without potential risks. Some of the common complications include:

• Pain and discomfort: Patients may experience pain or discomfort during and after the procedure, particularly as the stone fragments pass through the urinary tract.
• Hematuria: Blood in the urine is a common occurrence after ESWL, usually resolving within a few days.
• Steinstrasse: This term refers to the accumulation of stone fragments in the ureter, which can cause obstruction and pain. It may require additional intervention.
• Infection: The procedure can increase the risk of urinary tract infections, necessitating prompt medical attention if symptoms arise.

Nursing Care of a Patient Undergoing Extracorporeal Shock Wave Lithotripsy (ESWL)

Pre-Procedure Care

• Assessment: Conduct a thorough assessment, including medical history, current medications, and allergies. Ensure the patient has no contraindications for the procedure.
• Education: Educate the patient about the ESWL procedure, its purpose, and what to expect before, during, and after the treatment. Address any questions or concerns they may have.
• Preparation: Instruct the patient to fast for a specific period before the procedure, if required. Ensure they have arranged for transportation home post-procedure.

Intra-Procedure Care

• Monitoring: Continuously monitor the patient’s vital signs, including heart rate, blood pressure, and oxygen saturation. Observe for any signs of distress or discomfort.
• Positioning: Assist the patient in maintaining the correct position as per the physician’s instructions to ensure optimal targeting of the shock waves.
• Pain Management: Administer prescribed analgesics or sedatives to manage pain and anxiety during the procedure.

Post-Procedure Care

• Observation: Monitor the patient for a short period after the procedure to ensure stability before discharge. Check vital signs and assess for any immediate complications.
• Hydration: Encourage the patient to drink plenty of fluids to help flush out stone fragments. Provide instructions on fluid intake and possible dietary adjustments.
• Pain Management: Provide pain medication as prescribed to manage post-procedure discomfort. Advise the patient on pain management techniques and when to seek further medical advice if pain persists or worsens.
• Education and Follow-Up: Educate the patient on what to expect in the days following the procedure, including the presence of blood in the urine (hematuria) and the passage of stone fragments. Schedule follow-up appointments to assess the effectiveness of the treatment and monitor for complications such as infection or steinstrasse.

Managing Complications

• Pain and Discomfort: Monitor and manage pain levels using prescribed medications. Encourage the patient to rest and follow pain management guidelines.
• Hematuria: Inform the patient that blood in the urine is common and should resolve within a few days. If hematuria persists or is severe, advise them to seek medical attention.
• Steinstrasse: Be vigilant for signs of obstruction caused by stone fragments in the ureter. Symptoms may include severe pain, difficulty urinating, or reduced urine output. Prompt intervention may be required.
• Infection: Educate the patient on recognizing symptoms of urinary tract infections, such as fever, chills, and burning during urination. Encourage them to seek immediate medical care if these symptoms occur.

REFERENCES

1. Dasgupta R, Cameron S, Aucott L, MacLennan G, Thomas RE, Kilonzo MM, et al. Shockwave Lithotripsy Versus Ureteroscopic Treatment as Therapeutic Interventions for Stones of the Ureter (TISU): A Multicentre Randomised Controlled Non-inferiority Trial. Eur Urol. 2021 Jul. 80 (1):46-54.
2. Bovelander E, Weltings S, Rad M, van Kampen P, Pelger RCM, Roshani H. The Influence of Pain on the Outcome of Extracorporeal Shockwave Lithotripsy (https://pubmed.ncbi.nlm.nih.gov/31114465/). Curr Urol. 2019 Mar 8;12(2):81-87.
3. Talso, Michele & Tefik, Tzevat & Mantica, Guglielmo & Socarras, Moises & Kartalas-Goumas, Ioannis & Somani, Bhaskar & Esperto, Francesco. (2019). Extracorporeal shockwave lithotripsy: current knowledge and future perspectives. Minerva Urologica e Nefrologica. 71. 10.23736/S0393-2249.19.03415-5.
4. Scotland KB, Safaee Ardekani G, Chan JYH, Paterson RF, Chew BH. Total Surface Area Influences Stone Free Outcomes in Shock Wave Lithotripsy for Distal Ureteral Calculi. J Endourol. 2019 Aug. 33 (8):661-666
5. Katz MH, Doherty GM. Urology. In: Doherty GM, eds. Current Diagnosis & Treatment: Surgery. 15th ed. McGraw Hill; 2020.
6. National Kidney Foundation (U.S.). Lithotripsy (https://www.kidney.org/atoz/content/lithotripsy).
7. National Institute of Diabetes and Digestive and Kidney Diseases (U.S.). Treatment for Kidney Stones  https://www.niddk.nih.gov/health-information/urologic-diseases/kidney-stones/treatment. Last reviewed 5/2017.
8. Pricop C, Radavoi GD, Puia D, Vechiu C, Jinga V. Obesity: A Delicate Issue Choosing the ESWL Treatment for Patients With Kidney and Ureteral Stones? (https://pubmed.ncbi.nlm.nih.gov/31149074/) Acta Endocrinol (Buchar). 2019 Jan-Mar;-5(1):133-138.

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