Mini-PNL, RIRS, and ESWL for Treatment of Medium-Sized, High-Density, Non-Lower Pole, Renal Stones

The treatment options for renal stones 10-20 mm include either extracorporeal shock wave lithotripsy (SWL) or endourology (retrograde intrarenal surgery (RIRS) and percutaneous nephrolithotomy (PNL).

SWL is an attractive treatment option for renal stones because it is non-invasive and more acceptable for the patient and can be done under analgesia, sedation, or minimal anaesthesia. However, the limitation of SWL includes a relatively lower stone-free rate (SFR) and the need for repeated sessions and auxiliary procedures. The SFR after SWL is affected by several factors, including body mass index (BMI), stone size, intrarenal stone location, skin-to-stone distance (SSD), and stone density.

The EAU guidelines put endourology and SWL as two equal options in medium-sized non-lower pole renal stones and did not give special attention to the stone density, which is an important predictor for SWL outcome. Several studies reported that the number of SWL sessions increased with increased stone attenuation value (SAV) and SFR decreased significantly in high-density renal stone.

PNL and RIRS have good SFR compared to SWL but might entail a significant risk of morbidity. The improved fURS instrumentation and lithotripsy technology, and development of the miniaturized PNL technique, may lower the procedure-related complications and mPNL and RIRS an alternative and excellent option for medium-sized and even large renal stones The investigators hypothesize that addressing the stone density factor may give a clear recommendation for medium-sized, high-density renal stones. They expected the superiority for either mPNL or RIRS, regarding SFR, without increased morbidity.

The study aims to compare the outcome of mPNL, RIRS, and SWL for treatment of non-lower pole, high-density renal stones of 10 to 20 mm size.

The study will include adult patients with non-lower pole, high-density (>1000 HU) renal stones of 10 to 20 mm size.

Pre-operatively, patients will be evaluated by medical history taking, physical examination. urinalysis, urine culture, complete blood cell count (CBC), liver function tests, coagulation profile, blood urea nitrogen (BUN), serum creatinine, plain abdominal X-ray and computed tomography for urinary tract (CT-UT), Eligible patients will be randomly divided into 3 equal groups. PNL group, in which PNL procedures will be performed using miniature nephroscope, RIRS group, in which RIRS will be performed using flexible ureteroscope and SWL group, in which SWL procedures will be performed using Dornier Lithotripter.

post-operatively, patients will be followed up regularly, for 3 months. The SFR, complication rate, cost, patients' and surgeon's satisfaction will be evaluated and compared between the three groups using the appropriate statistical tests and analytical program.

Inclusion criteria

• Adult patients (both genders)
• Single non-lower pole renal stone.
• Stone size: 10-20 mm.
• Stone density: > 1000 HU.

Exclusion criteria

• Pregnant women.
• Morbid obesity.
• Severe orthopaedic deformities.
• Co-morbidities precluding general anaesthesia or prone positioning.
• Uncorrectable coagulation disorders.
• Active urinary tract infection (UTI).
• Stone in a calyceal diverticulum.
• Abnormal renal anatomy.
• Urinary tract obstruction distal to the stone.
• Concomitant pathology that needs intervention in the same setting.
• Advanced hydronephrosis.