This prospective, randomized study is comparing the safety and efficacy of using two types of ureteral access sheaths in managing staghorn renal stones by retrograde intrarenal surgery.

Staghorn renal calculi is a complex type of renal calculi characterized by their filling of the renal pelvis and branching into all or part of the renal calyces.

Percutaneous nephrolithotomy (PCNL) is currently the recommended primary treatment option for staghorn renal calculi. However, the procedure has significant drawbacks, including invasiveness, postoperative bleeding, infection, prolonged hospitalization, and slow recovery. Retrograde Intrarenal Surgery (RIRS), an effective minimally invasive procedure, has become the first-line treatment for stones smaller than 2cm. With advancements in endoscopic equipment and techniques, RIRS is also being gradually utilized for the treatment of staghorn renal calculi in patients who are not suitable for PCNL.

Ureteral access sheath (UAS) is an important tool for the endourologist. Advantages of using a UAS in ureteroscopy include: ena¬bling repeated passage of the ureteroscope while mini¬mizing damage, improving the flow of irrigation fluid and visualization within the ureter, reducing operative times, reducing the costs of procedures and improving the effectiveness of surgery.

Intending to overcome the shortages of RIRS, a patented ureter access sheath with features of suction and bendable-tip is designed. The tip of the innovated ureteral access sheath can reach the target calyx along with the flexible ureteroscope.

The adjustable continuous negative pressure suction ensures sufficient irrigation speed and maintains a clear surgical field of view, while effectively removing fragmented stones and dust, and reducing the thermal energy generated by laser lithotripsy.

Inclusion Criteria:

• Adult patients of both sexes.
• Patient has a staghorn renal stone (complete or partial staghorn).
• Normal renal function tests.
• Congenital renal anomalies as horseshoe, pelvic or mal-rotated kidneys.

Exclusion Criteria:

• Abnormal coagulation profile.
• Active or untreated urinary tract infection.
• Age under 18 years or above 70 years.
• Patient has a staghorn stone associated with other pathology which requires additional intervention, as ureteral stricture or ureteropelvic junction obstruction (UPJO).
• Pregnancy.