Lower-pole renal stones might represent a challenge in endoscopic treatment, especially for intermediate sizes (1–2 cm), that come with no strong indication or contraindication for one technique over the other [1]. The sharp infundibulopelvic angle, together with the infudibulopelvic width and length, often determine treatment choices, along with the available expertise, cost and patient choice. On the other hand, some might argue that it would be excessive to perform a percutaneous nephrolithotomy (PCNL) for intermediate stone sizes, when other technologies such as flexible ureteroscopy (f-URS) allow for a lesser invasive approach. One of the most frequently applied strategies to treat intermediate-size lower-pole stones is to relocate them in the upper pole or in the renal pelvis. Despite it being a feasible and efficient technique, stone relocation might sometimes be uneasy due to the stone size or the infundibulopelvic angle, prolonging the operative times.

In a recent prospective randomised trial, Elmansy et al. [1] compared the outcomes between f-URS and laser lithotripsy (f-URSL) and miniaturised PCNL (mini-PCNL) for these intermediate lower-pole stones without relocation. The most interesting finding of the study is indeed on the important difference in reported stone-free rates (SFRs). They found a 1-day SFR of 50% in the mini-PCNL group vs only 11.1% in the f-URSL group, increasing to 72.2% in the mini-PCNL and to 37.1% in the f-URSL group at 90-days follow-up. When including fragments up to 2 mm, the 3-month SFR rose in fact to 86.1% and 71.4% for mini-PCNL and f-URSL, respectively. Recent data from Brian et al. [2] show that over 50 months, residual fragments >4 mm have a disease progression rate of up to 88% and intervention rate of up to 47%.

Indeed, the difference between mini-PCNL and f-URSL reported by Elmansy et al. [1] is significant, favouring the percutaneous treatment [1]. These findings are in line with the literature, reporting higher SFR for PCNL compared to classic f-URSL [3]. In a recent review on 1–2 cm lower-pole stones, mini-PCNL showed in fact higher efficacy in complete stone clearance, while demonstrating comparable complications rates and operative times. The difficult position and manoeuvrability of the retrograde access could be addressed as the main limitation for treating this kind of calculi, reaching lower SFRs than the ones usually reported for stones located in medium/upper renal calyces. At the same time, mini-PCNL has shown good safety profiles, at least partially overcoming the classic limitations of the percutaneous access, namely the high bleeding risk and the need for a postoperative nephrostomy. In their study, Elmansy et al. [1] reported a low bleeding risk during the puncture (7.4%), and good triangulation outcomes avoiding the need for multiple punctures. They also aimed for totally tubeless procedures, lining up with the current, and successfully achieved it in >90% of the mini-PCNLs without influence on the postoperative complication rate.

Despite the reported superiority of mini-PCNL in achieving an optimal SFR, nowadays the introduction of laser technology with thulium fibre laser and suctioning techniques is gathering interest in the urological community as they might be able to overcome the classic downfalls of f-URS [4, 5]. Suctioning in f-URS can now be applied via a suction ureteric access sheath (UAS) or via a suction scope in the form of direct in scope suction. As a recent meta-analysis on the application of suction to both mini-PCNL and f-URSL revealed that this tool can significantly increase SFR, particularly for the retrograde technique [6]. Finding a comparable overall SFR between the two suctioning-aided techniques, Tzelves et al. [6] stated that the lithotripsy outcomes could be deeply influenced by suction, and this might overturn the outcomes as shown in the recent study by Elmansy et al. [1]. As in this study, f-URSL was performed with standard UAS, it might be inferred that the SFR outcomes could change if suctioning was applied. At the same time, there is a lack of research on the specific cohort of lower-pole stones, and we look forward to further investigation that could enlighten the exact role of suction for these and stones in difficult anatomical locations.

下极肾结石可能代表内窥镜治疗的挑战，尤其是对于中等大小 （1-2 cm） 的肾结石，其中一种技术优于另一种技术没有强烈的适应症或禁忌症 [1]。尖锐的漏斗骨盆角以及腹骨盆的宽度和长度通常决定了治疗选择，以及可用的专业知识、成本和患者的选择。另一方面，有些人可能会争辩说，当其他技术（如输尿管软镜检查 （f-URS） 允许侵入性较小的方法时，对中等大小的结石进行经皮肾镜取石术 （PCNL） 是过度的。治疗中等大小的下极结石最常用的策略之一是将它们重新定位在上极或肾盂中。尽管这是一种可行且有效的技术，但由于结石大小或漏斗盆角度，结石移位有时可能会感到不安，从而延长手术时间。

在最近的一项前瞻性随机试验中，Elmansy 等人 [1] 比较了 f-URS 与激光碎石术 （f-URSL） 和小型化 PCNL （mini-PCNL） 对这些中间低极结石的疗效，无需重新定位。该研究最有趣的发现确实是报告的无结石率 （SFR） 的重要差异。他们发现 mini-PCNL 组的 1 天 SFR 为 50%，而 f-URSL 组仅为 11.1%，在 90 天的随访中，mini-PCNL 增加到 72.2%，f-URSL 组增加到 37.1%。当包括最大 2 mm 的片段时，mini-PCNL 和 f-URSL 的 3 个月 SFR 实际上分别上升到 86.1% 和 71.4%。Brian 等人 [2] 的最新数据显示，在 50 个月内，残留片段 >4 mm 的疾病进展率高达 88%，干预率高达 47%。

事实上，Elmansy 等人 [1] 报道的 mini-PCNL 和 f-URSL 之间的差异很大，有利于经皮治疗 [1]。这些发现与文献一致，与传统的 f-URSL 相比，PCNL 的 SFR 更高 [3]。在最近一项关于 1-2 cm 下杆结石的综述中，mini-PCNL 实际上在完全清除结石方面显示出更高的疗效，同时显示出相当的并发症发生率和手术时间。逆行通路的困难位置和可操作性可以作为治疗这种结石的主要限制来解决，其 SFR 低于通常报道的位于中/上肾盏中的结石的 SFR。与此同时，mini-PCNL 显示出良好的安全性，至少部分克服了经皮通路的典型局限性，即高出血风险和术后肾造瘘术的需要。在他们的研究中，Elmansy 等人 [1] 报告了穿刺期间的出血风险较低 （7.4%），并且良好的三角测量结果避免了多次穿刺的需要。他们还以完全无管手术为目标，与电流保持一致，并在 >90% 的微型 PCNL 中成功实现了这一目标，而不会影响术后并发症发生率。

尽管据报道 mini-PCNL 在实现最佳 SFR 方面具有优势，但如今引入铥光纤激光和抽吸技术的激光技术引起了泌尿外科界的兴趣，因为它们可能能够克服 f-URS 的典型缺点 [4， 5]。f-URS 中的抽吸现在可以通过抽吸输尿管通路护套 （UAS） 或通过直接内镜抽吸形式的抽吸镜进行。正如最近一项关于抽吸在 mini-PCNL 和 f-URSL 中的应用的荟萃分析所揭示的那样，该工具可以显着增加 SFR，特别是对于逆行技术 [6]。Tzelves 等人 [6] 发现两种抽吸辅助技术之间的总体 SFR 相当，指出碎石术的结果可能会受到抽吸的深刻影响，这可能会推翻 Elmansy 等人最近的研究 [1] 所示的结果。与本研究一样，f-URSL 是使用标准 UAS 进行的，因此可以推断如果应用抽吸，SFR 结果可能会发生变化。同时，缺乏对特定低极结石队列的研究，我们期待进一步的调查，以阐明抽吸对这些结石和困难解剖位置的结石的确切作用。