Effect of Double J Stent on Outcomes of Extracorporeal Shock Wave Lithotripsy
Condition: Urolithiasis
MeSH terms: Urolithiasis
Study type: Interventional

Summary: 
      Background: Many studies showed that stone-free rates (SFRs) after extracorporeal shock wave
      lithotripsy (SWL) might be related to both the patient (body mass index; BMI, skin-to-stone
      distance; SSD), and stone related factors (location, stone size, and stone density). However,
      the possible effect of pre-stenting on success as well as complication rates after SWL has
      not been evaluated in detail to date. Taking this fact into account, the effect of
      pre-stenting on the outcomes of SWL treatment in renal stones must be evaluated in the
      absence of possible effects induced by the patient and stone-related factors. Aim: To
      evaluate the effect of double J (JJ) stents on SWL treatment of moderate sized (15-25-mm)
      renal pelvic stones. Study design: Randomized prospective study Methods: Between January 2016
      and December 2017, a total of 152 adult patients who were planned to undergo SWL for a single
      radiopaque renal pelvic stone were included in the study. Patients with solitary kidney,
      congenital abnormality, skeletal tract abnormalities, previous urinary system surgery,
      hydronephrosis (grade 2 or more), untreated urinary tract infection, bleeding disorder, and
      suspected pregnancy were excluded. The remaining 114 patients were randomly divided into two
      groups; nonstented and stented. Twenty-two patients whose stone could not be fragmented
      despite 3 consecutive sessions were also excluded from the study. A total of 92 patients (54
      non-stented and 38 stented) were included in the final analysis.
    

Detailed description: 
      Study design Between January 2016 and December 2017, a total of 152 adult (age > 18 years)
      patients who were planned to undergo extracorporeal shock wave lithotripsy (SWL) for a single
      radiopaque renal pelvic stone with a largest diameter of 15 to 25 mm were included in the
      study. Patients with solitary kidneys, congenital abnormalities, skeletal system
      abnormalities, previous urinary system surgery, hydronephrosis (grade 2 or more), untreated
      urinary tract infection, bleeding disorder, and suspected pregnancy were excluded from the
      study. The remaining 114 patients were randomly divided into two groups as non-stented (n=67)
      and stented (n=47). Randomization was performed by flipping a coin. During SWL procedures, 22
      patients whose stone could not be fragmented despite 3 consecutive sessions were also
      excluded from the study. A total of 92 patients (54 non-stented and 38 stented) were included
      in the final analysis.

      Preprocedural evaluation All patients were evaluated preoperatively using non-contrast
      computed tomography (CT). Prior to treatment, a complete urine test, if needed urine culture
      and antibiogram test, simple serum biochemistry and coagulation tests were performed in all
      patients. The impact of patient-related factors (age, sex, body mass index;BMI),
      stone-related factors (laterality, stone size and Hounsfield units; HU), renal parenchymal
      thickness (RPT), and skin-to-stone distance (SSD) on fragmentation were analyzed. Body mass
      index (BMI) was calculated by dividing the weight (kg) by the square of the height (m2). CT
      with 5-mm contiguous sections at 120 kw and 90 milliampere (mA) was performed in all patients
      using a multidetector row helical CT scanner (Somatom Plus; Siemens, Germany). The
      longitudinal stone dimension was calculated by multiplying collimation thickness and the
      number of images in which the stone seen. The transverse dimension was chosen as the diameter
      of stone from the image showing its largest width. The maximum dimension of the stone was
      accepted as the highest value measured, either the longitudinal or transverse diameter. The
      average CT attenuation value as the representative HU was measured by drawing a region of
      interest smaller than the stone in the image showing the stone in the largest dimension. The
      SSD was calculated by measuring the distance from the skin to the stone at posterolateral
      45°. All patients signed an informed consent form for SWL and pre-stenting. Stent size was
      4.8 French and 26 cm.

      SWL technique SWL was performed with an electromagnetic lithotripter Compact Sigma (Dornier
      Med Tech System Gesellschaft mit beschränkter Haftung; GmbH, Weßling, Germany) by the same
      operator, with the patient in the supine position, and with a standardized treatment angle
      under both fluoroscopic and ultrasonic guidance. SWL procedures were performed with analgesic
      application (75 mg diclofenac sodium). If needed, a compression bag was used to decrease
      stone movement caused by respiration. Each session was completed either after application of
      a total of 3000 shock waves or when the stone was completely disintegrated. The degree of
      shock wave power delivered during SWL was recorded as 1 to 6 and the shock wave frequency was
      90/minute. Individual power settings were adjusted according to the patient's tolerance.
      Patients were evaluated 1 week after each session through abdominal kidneys, ureters, and
      urinary bladder (KUB) X-ray and repeat treatment was performed in cases of inadequate
      disintegration. Management was stopped when there was no disintegration despite 3 SWL
      sessions. No patients received medical expulsive treatment (MET) before or after SWL
      sessions. JJ stents were removed after 4 weeks. In view of the radiographic assessment with
      CT performed 4 months following the last SWL session, treatment results were categorized as
      either successful or unsuccessful according to whether there were any residual stone
      fragments. During SWL sessions and after treatment, the number of emergency department visits
      and analgesic consumption were recorded.

      Statistical analysis Data were analyzed using the Statistical Package for the Social Sciences
      software version 19 (SPSS Inc., Chicago, Illinois, USA). Descriptive statistics were
      determined for the mean, standard deviation, lowest and highest, and ratio values. The
      distribution of the variables was measured using the Kolmogorov-Smirnov test. Univariate
      (Chi-square or t-test) tests were performed to determine whether there was a statistically
      significant difference for characteristics between the stented and non-stented groups. If
      parameters did not show normal dispersion, the Mann-Whitney U test, which is the
      nonparametric equivalent of the t-test, was performed. The threshold for statistical
      significance was accepted as p < 0.05 for all analyses.
    

Intervention name(s): SWL
Intervention type(s): Device
Intervention description(s): extracorporeal shockwave lithotripsy apply
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment