Small stone fragments inevitably result from breakage of a large stone and are almost impossible to be entirely extracted from the collecting system in current retrograde intrarenal surgery (RIRS) settings. While most of these clinically insignificant residual fragments (CIRFs; <4 mm) may pass spontaneously, increasing evidence suggests that these so-called CIRFs may act as an origin for new stone formation and eventually lead to re-intervention [1]. Therefore, it is of paramount importance to achieve complete stone-free status with the aim of improving patient’s quality of life not only physically but also psychologically and economically [2]. In the present study, we present an effective technique using a fibrin-based gel to clear out small stone fragments from the collecting system during RIRS. The fibrin-based gel used in this study was a self-modified version of a commercially available product that has already been widely used for haemostasis and wound sealing in various clinical settings. The original gel system includes two components: component A (main constitutes: fibrinogen and various fibrin stabilisers) and component B (thrombin and Ca²⁺). When diluted appropriately and supplemented with medical grade methylene blue, the two components form a blue fibrin gel that embeds and adheres stone fragments in the saline and urine environment within seconds after sufficient mixing. The fibrin gel-assisted stone extraction technique does not require any specific instruments other than standard RIRS requirements and serves as an ‘additional procedure’ that does not change the protocol of standard RIRS lithotripsy. This technique might fuel the growing popularity and expanding indication of RIRS in the treatment of upper tract stones, by reducing the risk of leaving behind CIRFs that can sometimes be clinically significant.

Patients bearing a single 10–30 mm upper tract stone without RIRS contradictions were enrolled in this study between February 2021 and July 2021. Patients were not routinely stented before surgery. Ureteric stents were placed in all patients on the affected side and routinely removed 2 weeks after RIRS. All patients were followed up for a minimum of 1 month (range 1–6 months).

在目前的逆行肾内手术 (RIRS) 环境中，小石头碎片不可避免地是由大石头破裂导致的，并且几乎不可能从收集系统中完全取出。虽然大多数这些临床上无关紧要的残余碎片（CIRF；<4 mm）可能会自发通过，但越来越多的证据表明，这些所谓的 CIRF 可能是新结石形成的起源，并最终导致重新干预 [ 1 ]。因此，达到完全无结石状态至关重要，目的不仅是在身体上，而且在心理上和经济上都可以提高患者的生活质量[ 2]。在本研究中，我们提出了一种有效的技术，使用基于纤维蛋白的凝胶在 RIRS 期间从收集系统中清除小石头碎片。本研究中使用的基于纤维蛋白的凝胶是市售产品的自我修改版本，该产品已广泛用于各种临床环境中的止血和伤口封闭。原凝胶体系包括两组分：组分A（主要成分：纤维蛋白原和各种纤维蛋白稳定剂）和组分B（凝血酶和Ca ²⁺）。当适当稀释并补充医用级亚甲蓝时，这两种成分会形成一种蓝色纤维蛋白凝胶，在充分混合后的几秒钟内将结石碎片嵌入并粘附在盐水和尿液环境中。除标准 RIRS 要求外，纤维蛋白凝胶辅助取石技术不需要任何特定仪器，并且作为“附加程序”，不会改变标准 RIRS 碎石术的协议。这种技术可能会通过降低留下有时可能具有临床意义的 CIRF 的风险来推动 RIRS 在上尿路结石治疗中的日益普及和扩大适应症。

在 2021 年 2 月至 2021 年 7 月期间，本研究招募了患有单一 10-30 毫米上尿路结石且无 RIRS 矛盾的患者。患者在手术前未常规植入支架。输尿管支架放置在患侧的所有患者中，并在 RIRS 后 2 周常规移除。所有患者至少随访 1 个月（范围 1-6 个月）。