Does ureteral stenting matter for stone size? A retrospectıve analyses of 1361 extracorporeal shock wave lithotripsy patients.

358 Central European Journal of Urology UROLITHIASIS ORIGINAL PAPER Does ureteral stenting matter for stone size? A retrospectıve analyses of 1361 extracorporeal shock wave lithotripsy patients Burak Ozkan1, Cagatay Dogan2, Gulce Ecem Can2, Nejat Tansu2, Ahmet Erozencı2, Bulent Onal2 Acıbadem Unıversıty, Faculty of Medıcıne, Department of Urology, Istanbul, Turkey Unıversıty of Istanbul, Cerrahpasa School of Medıcıne, Department of Urology, Istanbul, Turkey 1 2 Citation: Ozkan B, Dogan C, Can EG, Tansu N, Erozencı A, Onal B. Does ureteral stentıng matter for stone sıze? A retrospectıve analyses of 1361 extracorporeal shock wave lithotripsy patıents. Cent European J Urol. 2015; 68: 358-364. Article history Submitted: April 1, 2015 Accepted: June 24, 2015 Published on-line: Oct. 15, 2015 Corresponding author Burak Ozkan Acıbadem Unıversıty Department of Urology Halıt Zıya Usaklıgıl Cad. No. 1 Bakırkoy 34140 Istanbul, Turkey phone: +90 532 498 04 95 burakozkandoc@ hotmail.com Introduction The aim of our study was to determine the efficacy of ureteral stents for extracorporeal shock wave lithotripsy (SWL) treatment of pelvis renalis stones and to compare the results and complications in stented and non-stented patients. Material and methods Between 1995 and 2011, 1361 patients with pelvis renalis stones were treated with SWL. Patients were subdivided into three groups according to stone burden: ≤1 cm² (group 1; n = 514), 1.1 to 2 cm² (group 2; n = 530) and >2 cm² (group 3; n = 317). Each group was divided into subgroups of patients who did and did not undergo ureteral stent implantation before SWL treatment. The efficacy of treatment was evaluated by determining the effectiveness quotient (EQ). Statistical analysis was performed by chi-square, Fisher’s exact and Mann-Whitney U tests. Results Of the 514, 530 and 317 patients in groups 1, 2 and 3 respectively, 30 (6%), 44 (8%) and 104 (33%) patients underwent auxiliary stent implantation. Steinstrasse rates did not differ significantly between stented and non-stented patients in each group. The EQ was calculated as 62%, 33% and 70% respectively in non-stented, stented and totally for group 1. This ratio calculated as 58%, 25% and 63% for group 2 and 62%, 26% and 47% for group 3. Stone-free rates were significantly higher for non-stented than for stented patients in groups 2 and 3. Conclusions Stone free rates are significantly higher in non-stented than in stented patients with pelvis renalis stones >1 cm², whereas steinstrasse rates are not affected. Key Words: pelvis renalis stone ‹› stent ‹› SWL ‹› stone size INTRODUCTION Since its first application in 1980, extracorporeal shock wave lithotripsy (SWL) has become the preferred treatment method in many ureteric and kidney stone diseases [1]. Advances in stone treatment in the endoscopic age, such as the ability to perform retrograde intrarenal surgery more frequently and almost independently of the size of the stone and percutaneous nephrolithotripsy (PNL) gaining less invasive features defined as mini and micro, can be listed as developments that have hindered the preference Cent European J Urol 2015; 68: 358-364 of SWL [2]. The wide use of SWL is due to its higher efficacy in selected cases while its low morbidity rates is one of the most important advantages of this method, making it the first treatment choice in many cases today, despite the other treatment alternatives that are available. However, there are conditions that limit the use of the method and affect its success [2]. Among the factors that affect the success and results of SWL are; the type of lithotripter; stone-related factors such as the size, structure, number, and localization; the anatomy and the functioning of the kidney; and patient–specific structural features [3, 4, 5]. doi: 10.5173/ceju.2015.611 359 Central European Journal of Urology Al–Ansari et al. investigated the prognostic factors affecting the success of SWL in 427 patients and they demonstrated that in cases with renal stones larger than 30 mm, the stone’s size, localization, number, radiologic renal features and congenital renal anomalies were significant factors, while ureteral stent use, age, gender, and the nature of the stone (de novo or recurrent) had no effect [6]. Abdel-Khalek et al. reached the same conclusions in their study of 2954 cases with renal stones that were smaller than 30 mm [7]. In addition, factors such as the presence of additional interventions pre- and post-SWL, complications, and costs can also affect the efficacy of the treatment [2, 3, 4, 7]. The routine use of ureteral stent prior to SWL is not recommended in renal stone cases despite the lack of any defined criteria in the guidelines [2, 8]. While the use of ureteral stents can reduce post-SWL complications such as obstruction and renal colic, it does not prevent steinstrasse formation and infectious complications, and does not increase stone-free rates [8, 9, 10]. Patient discomfort, pain in bladder, and issues related to urination that are associated with ureteral stent use can often be experienced [11]. According to Kirkali et al., pre-SWL ureteral stent use should be preferred only in solitary kidney patients [12]. The goal of our retrospective study of over 1361 patients was to compare the stone-free rates, steinstrasse formation, treatment efficacy and complications between patients with renal pelvic stones with and without pre-SWL stent and to contribute to medical literature based on real life experiences. MATERIAL AND METHODS This is a retrospective study conducted by scanning the medical data of 1378 patients treated with SWL for renal pelvic stones at our clinic between 1995 and 2011. Seventeen patients who had percutaneous nephrostomy tube placement prior to SWL were excluded from the study. The median age of the 1361 patients included in the study was 40 (1-85) years. All patients had routine renal function tests, urinalysis and urine culture, coagulation tests, kidney-ureter-bladder X-ray (KUB), intravenous pyelography (IVP), and ultrasonography (USG) before SWL. An abdominal contrast-free computerized tomography (CT) was performed when required. Patients with urinary system infections were treated with antibiotics according to their culture results prior to SWL. Uncontrolled infections, coagulation dysfunctions, ureteropelvic junction obstruction, and pregnancy were considered contraindications for SWL. The SWL procedure was carried out via Siemens Lithostar Lithotripter (Siemens Medizinische Technik, Erlangen, Germany). The size of the stone was calculated in squared centimeters, by multiplying the widest width and length observed in KUB. When multiple stones were observed, the sum of their sizes was calculated. In order to avoid statistical bias in this study, the patients were separated into 3 groups based on the size of the stone: ≤1 cm (group 1), 1.1–2 cm² (group 2), and >2 cm² (group 3). Table 1 displays the patient chara (...truncated)