Introduction
The evolutional history of retrograde intrarenal surgery (RIRS) dates back to the 1970s, but the clinical usage of this technique has gained increasing popularity in the last 2 decades [1]. The functional developments of flexible ureteroscopes, lasers and ancillary equipment have led RIRS to become a significant surgical technique for the treatment of upper urinary system stones [2]. Due to these technological advancements, the guidelines for the treatment of urinary system stone disease have been frequently revised.
Despite these technological advancements, extracorporeal shock wave lithotripsy (ESWL) still maintains its importance for the treatment of upper urinary system stones less than 2 cm. in diameter. On the other hand, recent studies reporting the trends of urolithiasis treatment have shown a significant increase in the use of ureteroscopy compared to ESWL [3-5]. RIRS and ESWL are the 2 main treatments for proximal ureter stones. The European Association of Urology (EAU) guidelines recommend ureteroscopy as the first-line treatment for proximal ureter stones >10 mm, and ureteroscopy or ESWL for proximal ureter stones <10 mm [6]. According to the American Urology Association and Endourology Society guidelines, ureteroscopy is recommended as the treatment modality for proximal ureter stones of any size [7,8]. The efficacy and the safety of RIRS has led this procedure to replace the role of ESWL in the treatment of proximal ureter stones. On the other hand, expensive and fragile surgical equipment make this surgery a costly procedure. For this reason, there are several clinics that perform ESWL as the first-line treatment of proximal ureter stones and prefer RIRS as the second-line treatment for patients in which ESWL is not successful.
ESWL has proven to be a safe and effective method for the treatment of urinary system stones; however, it may lead to tissue damage, that is localized around the target zone. Animal studies have documented that ESWL causes torn vessels with platelet aggregation; vacuolization to complete necrosis of the epithelium and vascular smooth tissue; and aggregation of red blood cells and leukocytes in the interstitial space. The micro-environmental changes lead to tissue oedema and an inflammatory reaction around the target stone [9]. This reaction may also occur at the ureter wall around the stone, and may cause the stone to impact at the ureteric mucosa. The traumatic effect of ESWL on the ureteral wall and mucosal oedema may be considered a complication of RIRS that affects the efficiency and safety of this procedure.
We hypothesized that performing ESWL on proximal ureter stones before RIRS may be a disadvantage for the efficiency and safety of the surgery. In order to determine the validity of our hypothesis, we evaluated the effect of pre-RIRS ESWL on the efficiency and safety of RIRS in the treatment of proximal ureter stones.