This multicenter, randomized, controlled superiority trial (the SCULPT trial) aims to compare the efficacy and safety of a novel steerable flexible and navigable suction ureteral access sheath (FANS) versus the conventional FANS in the treatment of lower pole renal stones ≤2 cm. Lower pole stones are particularly challenging due to the narrow infundibular-pelvic anatomy that limits the maneuverability of standard FANS. The steerable FANS incorporates an active deflection mechanism that allows for independent control, potentially improving the success rate of accessing the lower pole calyx, performing laser lithotripsy, and aspirating stone fragments without additional adjuncts.
A total of 400 patients from 20 high-volume urological centers in China (approximately 20 patients per center) will be randomized in a 1:1 ratio to receive either steerable FANS or conventional FANS during flexible ureteroscopy. Primary outcome measures include the success rate of FANS navigation into the lower pole calyx as evidenced by direct stone visualization, effective laser lithotripsy, and successful stone aspiration. Secondary outcomes will assess immediate and 1-month stone-free rates, operative time, complication rates, instrument durability, and improvements in quality of life. This study is expected to provide critical evidence to guide clinical decision-making and potentially improve treatment efficiency for challenging lower pole renal stones.
Adults aged 18-75 years
Diagnosed with a single lower pole renal stone ≤2 cm by CT
American Society of Anesthesiology (ASA) score of 1-3
Ability to provide written informed consent
Patients with urinary tract anatomical abnormalities (e.g., horseshoe kidney, ileal conduit)
Untreated urinary tract infection
Presence of multiple stones or stones located outside the lower pole
Absolute contraindications to flexible ureteroscopy
Parallel
Steerable FANS
DeviceThis device is designed for flexible ureteroscopy procedures in patients with lower pole renal stones ≤2 cm. It features an active deflection mechanism that enables independent adjustment to enhance access into the lower pole calyx. The description focuses solely on the device and does not include procedural details already provided in the arm description.
Conventional FANS
DeviceThis device is intended for use in flexible ureteroscopy for lower pole renal stone management. It relies on passive deflection provided by the flexible ureteroscope for navigation into the lower pole calyx. The description is limited to the device characteristics without duplicating procedural details from the arm description.
Success Rate of Lower Pole Navigation
This outcome is defined as the proportion of cases in which the FANS (either steerable or conventional) successfully navigates into the lower pole renal calyx. Success is evidenced by the ability to directly visualize the stone, perform effective laser lithotripsy, and aspirate stone fragments without requiring additional adjunctive devices.
Immediate Stone-Free Rate
Proportion of patients with no residual stones or fragments \>2 mm on CT scan performed within 24 hours postoperatively.
Final Stone-Free Rate
Proportion of patients with complete stone clearance or fragments ≤2 mm, as confirmed by low-dose CT scan at 1 month postoperatively.
Operative Time
Duration from the insertion of the flexible ureteroscope into the urethra until the completion of double-J stent placement.
Duration of Hospital Stay
Total number of whole days from the day of surgery to the day of discharge.
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The First Affiliated Hospital of Guangzhou Medical University
Lead sponsor
Third Medical Center of Chinese PLA General Hospital
Collaborator
First Affiliated Hospital of Chongqing Medical University
Collaborator
Peking University People's Hospital
Collaborator
The Second Affiliated Hospital of Kunming Medical University
Collaborator
The Fifth Affiliated Hospital, Sun Yat-sen University
Collaborator
Henan Provincial People's Hospital
Collaborator
Nanfang Hospital, Southern Medical University
Collaborator
Wuhan Hospital of Traditional Chinese Medicine
Collaborator
Dongguan People's Hospital
Collaborator
Changzhou No.2 People's Hospital
Collaborator
Dongguan Tungwah Hospital
Collaborator
Panzhihua Central Hospital
Collaborator
Yan'an Affiliated Hospital of Kunming Medical University
Collaborator
NO.1 People's Hospital of Dali City
Collaborator
Huadu District People's Hospital of Guangzhou
Collaborator
Jiangmen Central Hospital
Collaborator
Shaoyang Central Hospital
Collaborator
Guangzhou Medical University Affiliated Qingyuan Hospital
Collaborator
Dongguan Kanghua Hospital
Collaborator
