Ultra Mini Percutaneous Nephrolithotomy VS Stented Extracorporeal Shock Wave Lithotripsy for Stone Management
Condition: Renal Stone
MeSH terms: Kidney Calculi; Nephrolithiasis
Study type: Interventional

Summary: 
      Nephrolithiasis is the third most common disease of the urinary tract. As minimally invasive
      technologies develop, shock wave lithotripsy (SWL), retrograde intrarenal surgery (RIRS), and
      percutaneous nephrolithotomy (PCNL) are different surgeries to treat renal stones.

      Aim of the Study is to compare results, safety and outcome of Ultra mini PCNL versus stented
      extracorporeal shock wave lithotripsy (SWL) for the management of renal calculi from 10 - 20
      mm. Patients were randomized to either Ultra-Mini-Percutaneous nephrolithotomy group or
      stented SWL group via the closed envelope method. Patient data was collected preoperatively,
      immediately postoperatively and 2 and 4 weeks postoperatively to assess operative time,
      hospital stay, complications regarding fever, hematuria and need for blood transfusion,
      residual stones and need for retreatment.
    

Detailed description: 
      Nephrolithiasis is the third most common disease of the urinary tract, following urinary
      tract infections and Prostatic diseases. It also has a 1-year recurrence rate of 7% and
      10-year recurrence rate of 50%.

      Management of renal stones had seen a great shift over the last ten years. The need to find a
      balance between morbidity and stone clearance is always the milestone of treatment choice.
      Low risk procedure with high retreatment percentage vs another relatively higher risk
      procedure with lower retreatment chances.

      As minimally invasive technologies develop, shock wave lithotripsy (SWL), retrograde
      intrarenal surgery (RIRS), and percutaneous nephrolithotomy (PCNL) are different surgeries to
      treat renal stones. Open, laparoscopic, and robotic surgeries have their place only in highly
      selected patients.

      In the European Association of Urology (EAU) Guidelines on Urolithiasis, PCNL is a treatment
      of choice (TOC) for renal stones > 20 mm, SWL or RIRS is the first-line therapy for renal
      stones < 10 mm, and SWL or endourologic treatment (all PCNL and ureteroscopic interventions)
      can be performed for stones 10-20 mm.

      SWL is a minimally invasive intervention with good patient tolerance; it is regarded as the
      first line treatment for nephrolithiasis < 20 mm in size. Poor clearance of lower calyceal
      stone fragments due to gravity or unfavorable infundibulopelvic angle limits the efficacy of
      SWL for treating lower calyceal stones.

      flexible ureteroscopy increased quality and performance of upper urinary tract exploration,
      allowing the treatment the majority of stones at all sites. Experiences with RIRS have
      revealed higher stone-free rate (SFR) with less risk of renal damage and bleeding.
      Nevertheless, RIRS is also associated with some disadvantages as the possible need for staged
      procedures, risk of ureteral injuries and the costs of acquisition and maintenance of the
      complex endourological instruments and those issues can be possible factors that might have
      limited the capillary diffusion of this endoscopic procedure.

      Percutaneous nephrolithotripsy (24-30F) remains the standard procedure for treating large
      renal calculi. While achieving high SFR, it also has many drawbacks such as bleeding,
      postoperative pain, and a long recovery period due to its large access tract, so the mini
      percutaneous nephrolithotripsy (14-22F) with a smaller tract size came into existence. To
      reduce renal parenchymal injury associated with standard PCNL, minimally invasive PCNL with a
      smaller tract size has been developed. Depending on the size of the access tract, minimally
      invasive PCNL can be classified into Mini-PCNL (14- 22Fr), Ultra-mini-PCNL (11-13Fr).

      PCNL carried a significantly higher stone free rate than RIRS, especially for lower calyceal
      stones (OR=2.65, P=.003), however Mini-PCNL was at the expense of a longer hospital stay and
      an increased hemoglobin drop.

      Although PCNL could exhibit a stone free rate of 93.8%, a global survey revealed that it
      carried a complication rate of up to 14.5%.

      Ulra-mini-PCNL offer a particular advantage for difficult to access calculi, impacted lower
      pole calculi with an acute infundibular angle or stones in a calyceal diverticulum, with the
      greater advantage of reduced bleeding.

      This study was conducted at Urology department, Faculty of Medicine, Ain Shams University.
      Inclusion criteria included patients between 18 and 60 years, complaining of radioopaque
      renal stones ranging from 10-20 mm with BMI not exceeding 40 Exclusion criteria were patients
      who had radiolucent stones, smaller than 10 mm or larger than 20 mm, with congenital renal
      anomalies or spinal deformity or BMI exceeding 40. Patients with uncorrected bleeding
      diathesis or pregnant females or untreated urinary tract infection were also excluded.

      In this study patients were recruited from the outpatient urology clinic between March 2021
      till March 2022.

      Using Power Analysis and Sample Size Software version 15 program for sample size calculation
      after reviewing results from a previous study (Zhang et al, 2019) we assume a medium effect
      size difference between the two groups regarding the stone-free rate ( d=0.6), based on these
      findings sample size of 90 patients (45 per group) achieve 80% power to reject the null
      hypothesis of zero effect size when the population effect size is 0.60 and the significance
      level (alpha) is 0.050 using a two-sided z test.

      Patients were randomized to either Group A Ultra-Mini-Percutaneous nephrolithotomy group or
      Group B stented SWL group via the closed envelope method.

      Preoperative evaluation including careful history taking, general and local examination,
      urine analysis, perioperative labs (CBC, bleeding profile, liver and renal functions),
      Computerized tomography Urinary Tract (CTUT) with Hounsfield unit estimation and Plain X-ray
      of the urinary tract (KUB).

      All patients were given perioperative antibiotic prophylaxis. In The Ultra-Mini-percutaneous
      nephrolithotomy group, a 5 Fr open-ended ureteral catheter was introduced in the renal
      pelvis, and a retrograde pyelogram was performed in the Lithotomy position after the
      induction of general anesthesia. Patients were then repositioned to the prone position.
      Ultra-mini-PCNLs were done in a prone position by a single consultant. The desired calyx was
      punctured with a Cook diamond tip puncture needle under fluoroscopy guidance using standard
      bull's eye technique. Single tract dilatation with One Step Dilator (11Fr), with central
      channel for guide wires with its Operating Sheath (Storz Dilator and Operating Sheaths for
      Minimal Invasive PCNL (MIP) XS) under fluoroscopy guidance. Storz Nephroscope for MIP XS / S
      along with Swiss Lithoclast master pneumatic lithotripter with 1/0.8 mm probe was used for
      stone fragmentation. Stone fragments are flushed out on rapid removal of the endoscope, due
      to a 'vortex' effect and with wash through the operating sheath using a 6 Fr. nelaton
      catheter.

      In the stented Extracorporeal ShockWave Lithotripsy (ESWL) group, a 5 Fr open-ended ureteral
      catheter was introduced in the renal pelvis, and a retrograde pyelogram was performed in the
      Lithotomy position after the induction of general anaesthesia JJ is applied either 5-26 or
      5-28 according to the patient. ESWL was administered with an electromagnetic shockwave
      lithotripter (Siemens electromagnetic lithotripters devices). Patients were positioned supine
      with the shock head from the back. Fluoroscopy was used for the localization and monitoring
      of stone fragmentation. All patients received shocks at a frequency of 60/min. An average of
      approximately 2500-3000 shocks was targeted in all patients.

      Follow up of patients was done postoperative immediately including careful and detailed
      history taking and examination including pain, fever, sepsis, and hematuria. Serum Hb level,
      S.creatinine, BUN, Na+, K+
    

Intervention name(s): Ultra-Mini-PCNL; Stented SWL
Intervention type(s): Procedure; Procedure
Intervention description(s): treatment to extract or disintegrate renal stones; treatment to disintegrate renal stones in the presence of a JJ
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: 90 Patients were enrolled from the outpatient urology clinic of Ain Shams University hospital (Demredash Hospital) randomized to either Group A Ultra-Mini-Percutaneous nephrolithotomy group or Group B stented SWL group via the closed envelope method.
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Nephrolithiasis; Ultra-Mini-PCNL; Stented SWL