The concept of the endoscopic access to the renal collecting systems for the diagnosis and treatment of upper urinary tract diseases was firstly introduced by V. Marshall who first described in 1964 the navigation in the renal pelvis with a rudimental flexible fiberscope. Retrograde intrarenal surgery (RIRS) by means of flexible ureterorenoscopes (fURSs) is considered one of the first-line treatment options for the active removal of renal stones. Ureteroscopic Lithotripsy (URSL) with the holmium laser is an effective and safe method for treating ureterolithiasis. After RIRS, one of the technical aspect is the placement of a double-J stent. The underlying rationale of ureteric stent is to allow the urinary flow to bypass internal or external obstructions, which impair its drainage. 'Double-J' refers to the most common type of stent design that was initially introduced by Finney in 1978. The term 'double-J' refers to the 'J' shape of each end of the stent, which is designed to anchor the stent and prevent its displacement. The mean size of normal ureter is 1.8mm with a standard deviation of 0.9 mm. The standard size for double J stents is typically 6 Fr. Few studies have been done comparing standard 6Fr and smaller sized DJ stent. One study published in March 2018 has shown 4Fr stent superior to 5Fr and 6Fr stent. A Randomised Control Trial (RCT) published in July 2018 has shown 4.8 Fr stent superior to 6Fr stent. To assess ureteral stent-related symptoms, Joshi et al. described and validated the Ureteral Stent Related Symptom Questionnaire (USSQ) in 2003. This self-administered questionnaire includes questions in six sections: urinary symptoms, body pain, general health, work performance, sexual matters, and additional problems. The total score is the sum of all questions. This questionnaire can define and compare stent-related symptoms.

DJ stent cause significant side effects. Dysuria, urinary frequency and urgency were reported by 40%, 50% and 55% of the patients, respectively. Flank pain, gross hematuria and fever was reported by 32%, 42% and 15% respectively. Anxiety and sleep disturbance were reported by 24% and 20% respectively, and 45% of patients reported impairment in their quality of life. Decreased libido was reported by 45%, and sexual dysfunction by 42% of men and 86% of women. With few studies showing small sized DJ stent causing less symptoms that standard 6Fr stents; our study aims to ascertain whether the previous studies were in line to change the standard size of DJ stent from 6Fr to smaller size, possibly 4Fr. 6Fr DJ stent is commonly used in our center. This study is aimed to compare standard size of DJ stent with small size in TUTH.

All cases of urinary tract stones requiring endourologic intervention will be sampled for study and cases meeting the inclusion criteria will be randomized via simple random sampling and computer generated numbers enclosed in a sealed envelope opened just prior to surgery, into two groups: Group A 6Fr and Group B 4Fr. All cases will receive a single dose of ceftriaxone intraoperatively. RIRS will be done using Ureteral Access Sheath (UAS) 9.5-11.5 Fr. DJ Stent 4Fr or 6Fr will be used and length of DJ Stent will be 26cm. Stent will be removed on the 14th postoperative day. Symptoms will be assessed on day 3, day 7 and on the day of stent removal. Stone Clearance will be assured after 1 month with ultrasonography of abdomen.