An International Multi-center Prospective Cohort Study Comparing the Safety and Efficacy of Super-mini-PCNL, Mini-PCNL and Standard PCNL in the Treatment of ≥2cm Renal Stones

BACKGROUND AND RATIONALE Percutaneous nephrolithotomy (PCNL) is the first-choice for the treatment of renal stone ≥20 mm with high stone free rate (SFR). However, there are some sever complications such as bleeding. Severe bleeding needs arterial embolization, which might impair the renal function. The size of percutaneous access tract has been proven to be closely related to the risk of bleeding complications. Mini-PCNL was firstly introduced by Jackman in 1998 to treat pediatric renal stone with the aim to lower the morbidity. Mini-PCNL was gradually applied to adults. In recent years, urologists were still attempting to reduce size of the sheath and modify the sheath. They aimed to reduce the risk of bleeding. The first generation SMP consists of a 10-14 F access sheath with a suction-evacuation function and a 7-F nephroscope with enhanced irrigation was introduced by Guohua Zeng's group in 2014. In 2016, Guohua Zeng's group continued to introduce a modified SMP technique and system. The most remarkable feature of the new generation super-mini percutaneous nephrolithotomy (New-SMP) was metal irrigation-suction sheath which made the new system have higher efficiency than the old one. With the modified SMP technique and system, SMP was performed to treat large renal stone. (≥2cm). Moreover, SMP with an irrigation-suction sheath obviously improved the efficiency of removing the fragments and lower the intrapelvic pressure.

Although miniaturized techniques decreased the bleeding-related morbidity and have a similar SFR, they seemed to take a longer operating time and have risk of getting infectious complications. However, till now, no high quality of evidence demonstrated that what size of tract is the best for the treatment of ≥2 cm renal stone. Perhaps the investigators should find out a subgroup suitable for standard-PCNL, Mini-PCNL or SMP respectively.

STUDY OBJECTIVES The aim of this registry is to review current clinical practice on PCNL for stone treatment. The investigators will explore the answers to the following questions: What kind of PCNL urologists prefers to used? Is there a best cutoff based on the size of stones to divide the patients into subgroups, or a scoring system to decide which kind of PCNL is the best choice for individuals? Primary Objective To compare the stone free rate (SFR) (%) among standard-PCNL, Mini-PCNL and SMP for the treatment of ≥2 cm renal stone.

Secondary Objectives

1. Bleeding complication: hematocrit drop (g/L) and rate of transfusion (%).
2. Infectious complication: rate of getting fever (≥38℃) (%) and urosepsis (%).
3. Intraoperative indexes: operating time (mins), rate of tubeless/total tubeless (%).
4. Postoperative indexes: hospital stay (mins), visual analogue scale (VAS) score (range from 0-10, the higher value represents the worse outcome) STUDY DESIGN This study is a prospective, observational, international, multicenter registry cohort study SELECTION AND ENROLLMENT OF PARTICIPANTS Clinical Recruitment All sites for this pilot study are recruited by IAU Members. Each participating center should obtain ethical approval, as needed, according to local regulations.