Role of simulation in kidney stone disease:A systematic review of literature trends in the 26 years

BACKGROUND Minimally invasive techniques for treatment of urinary stones requires expertise,experience and endoscopic skills.Simulators provide a low-stress and low-risk environment while providing a realistic set-up and training opportunities.AIM To report the publication trend of‘simulation in urolithiasis’over the last 26 years.METHODS Research of all published papers on“Simulation in Urolithiasis”was performed through PubMed database over the last 26 years,from January 1997 to December 2022.Papers were labelled and divided in three subgroups:(1)Training papers;(2)Clinical simulation application or surgical procedures;and(3)Diagnostic radiology simulation.Each subgroup was then divided into two 13-year time periods to compare and identify the contrast of different decades:period-1(1997-2009)and period-2(2010-2022).RESULTS A total of 168 articles published on the application of simulation in urolithiasis over the last 26 years(training:n=94,surgical procedures:n=66,and radiology:n=8).The overall number of papers published in simulation in urolithiasis was 35 in Period-1 and 129 in Period-2,an increase of+269%(P=0.0002).Each subgroup shows a growing trend of publications from Period-1 to Period-2:training papers+279%(P=0.001),surgical simulations+264%(P=0.0180)and radiological simulations+200%(P=0.2105).CONCLUSION In the last decades there has been a step up of papers regarding training protocols with the aid of various simulation devices,with simulators now a part of training programs.With the development of 3D-printed and high-fidelity models,simulation for surgical procedure planning and patients counseling is also a growing field and this trend will continue to rise in the next few years.

Appropriate kidney stone size for ureteroscopic lithotripsy:When to switch to a percutaneous approach

Flexible ureteroscopy(f URS) has become a more effective and safer treatment for whole upper urinary tract stones. Percutaneous nephrolithotomy(PNL) is currently the first-line recommended treatment for large kidney stones ≥ 20 mm and it has an excellent stone-free rate for large kidney stones. However, its invasiveness is not negligible considering its major complication rates. Staged f URS is a practical treatmentfor such large kidney stones because f URS has a minimal blood transfusion risk, short hospitalization and few restrictions on daily routines. However, as the stone size becomes larger, the stone-free rate decreases, and the number of operations required increases. Therefore, in our opinion, staged f URS is a practical option for kidney stones 20 to 40 mm. Miniaturized PNL combined with f URS should be considered to be a preferred option for stones larger than 40 mm. Moreover, URS is an effective treatment for multiple upper urinary tract stones. Especially for patients with a stone burden < 20 mm, URS is a favorable option that promises a high stone-free rate after a single session either unilaterally or bilaterally. However, for patients with a stone burden ≥ 20 mm, a staged operation should be considered to achieve stone-free status.

Histopathological analysis of infiltrating T cell subsets in acute T cell-mediated rejection in the kidney transplant

AIM To compare the differential immune T cell subset com-position in patients with acute T cell-mediated rejection in the kidney transplant with subset composition in the absence of rejection, and to explore the association of their respective immune profiles with kidney transplant outcomes.METHODS A pilot cross-sectional histopathological analysis of the immune infiltrate was performed using immunohistochemistry in a cohort of 14 patients with acute T cellmediated rejection in the kidney transplant and 7 kidney transplant patients with no rejection subjected to biopsy to investigate acute kidney transplant dysfunction. All patients were recruited consecutively from 2012 to 2014 at the Singapore General Hospital. Association of the immune infiltrates with kidney transplant outcomes at up to 54 mo of follow up was also explored prospectively.RESULTS In a comparison to the absence of rejection, acute T cell-mediated rejection in the kidney transplant was characterised by numerical dominance of cytotoxic T lymphocytes over Foxp3^+ regulatory T cells, but did not reach statistical significance owing to the small sample size in our pilot study. There was no obvious difference in absolute numbers of infiltrating cytotoxic T lymphocytes, Foxp3^+ regulatory T cells and Th17 cells between the two patient groups when quantified separately. Our exploratory analysis on associations of T cell subset quantifications with kidney transplant outcomes revealed that the degree of Th17 cell infiltration was significantly associated with shorter time to doubling of creatinine and shorter time to transplant loss.CONCLUSION Although this was a small pilot study, results support our suspicion that in kidney transplant patients the immune balance in acute T cell-mediated rejection is tilted towards the pro-rejection forces and prompt larger and more sophisticated studies.

Education and training evolution in urolithiasis:A perspective from European School of Urology

Objective:With the worldwide increase in urolithiasis prevalence,the present study aimed to delineate and summarise recent evolutions in training for the management of urolithiasis.Methods:A PubMed search using the key words“simulation”,“training”,“ureteroscopy”,“RIRS”,“URS”,“percutaneous nephrolithotomy”,“PCNL”,“virtual reality”,“augmented reality”,“artificial intelligence”,“healthcare”,“curriculum”,and“assessment”was used to examine how education and training in urolithiasis have adapted over recent years.Focus was placed on the role of high-and low-fidelity simulation models,virtual reality and artificial intelligence,and standardised assessment and curriculum.Results:This review supports the necessity to incorporate technology,simulation,and other skill enhancement training modalities into surgical training.However,these cannot solely replace mentored training with an experienced professional supervisor.Whilst technological and simulation advancements are likely to prove increasingly important in urolithiasis training,it is just as important for stratification of robust curricula with validated assessment.We also propose a pathway for future training.Conclusion:Endourology subspeciality training programmes have successfully incorporated simulation model-based training for skill acquisition,refinement,and improving operative outcomes.Success is achieved by maintaining a delicate balance between machine and in person mentor-based training.A trainee-centred model that follows the proposed curriculum could aid this balance for the future generation of trainees.

Bilateral hematoma after tubeless percutaneous nephrolithotomy for unilateral horseshoe kidney stones:A case report

BACKGROUND Bilateral perirenal hematoma is rarely reported in endoscopic management of horseshoe kidney stones,and there are few studies reporting the formation of bilateral hematoma following tubeless percutaneous nephrolithotomy(PCNL)for unilateral horseshoe kidney calculi.CASE SUMMARY A 32-year-old man was admitted to our hospital because of repeated intermittent hematuria for 10 years.Plain abdominal computed tomography(CT)scan revealed calculi in the horseshoe kidney;the largest being 2 cm in diameter.Tubeless PCNL was performed to remove the stones.Three days after the operation,the patient was discharged in a stable situation.Three days after discharge,the patient presented to our emergency department because of right low back pain and vomiting.Emergent CT scan revealed subcapsular and perirenal hematocele and exudates in both kidneys.Ultrasound-guided puncture and drainage of perirenal effusion were performed.After the temperature stabilized,the patient received low-pressure injection of urokinase 100000 U for 3 d.His routine blood indexes and the renal function returned to normal in 3 wk.CT re-examination 3 mo after lithotripsy showed that the subcapsular and perirenal hematoma and exudates in both kidneys were significantly absorbed as compared with those before.The patient was followed up for 1 year,during which no flank pain or hematuria recurred.CONCLUSION This is the first case report on the formation of bilateral hematoma following tubeless PCNL for unilateral horseshoe kidney calculi.

A pilot clinical study of developing an External Assist Targeting Device for rapid and precise renal calyx access during percutaneous nephrolithotomy

Objective:To design a device to increase the accuracy of the targeting process and reduce the radiation exposure to both the patients and the medical staff.Methods:We analyzed the inherent problem and designed the External Assist Targeting Device(EATD)to assist in the alignment of needle targeting on the desired renal calyx under fluoroscopic guidance.The EATD was designed to allow rapid and precise access to calyces at all angles,with a simple two-step puncture protocol developed for puncturing a target renal calyx.We then tested the device in a pilot human trial with four patients.Results:In experiments with phantom models,the time for successful targeting was reduced by 31%using the device.The mean fluoroscopic time was reduced by 40%.In initial human trial,the puncture time was shortened by 66%and the radiation dose was decreased by 65%compared to free-hand technique.No complication was observed during the trial.Conclusion:The EATD was found to be cost effective,portable,simple to set up,and safe to operate for assisting in the percutaneous nephrolithotomy procedures.Our preliminary tests showed high degree of accuracy in gaining precise access to a targeted renal calyx with much shorter time and lesser radiation dose.The EATD also has the potential to be used to access other organs with precision under fluoroscopic guidance.

Effect of liver transplantation with primary hyperoxaluria type 1:Five case reports and review of literature

BACKGROUND Primary hyperoxaluria type 1(PH1)is a rare autosomal recessive disease stemming from a deficiency in liver-specific alanine-glyoxylate aminotransferase,resulting in increased endogenous oxalate deposition and end-stage renal disease.Organ transplantation is the only effective treatment.However,its approach and timing remain controversial.CASE SUMMARY We retrospectively analyzed 5 patients diagnosed with PH1 from the Liver Transplant Center of the Beijing Friendship Hospital from March 2017 to December 2020.Our cohort included 4 males and 1 female.The median age at onset was 4.0 years(range:1.0-5.0),age at diagnosis was 12.2 years(range:6.7-23.5),age at liver transplantation(LT)was 12.2 years(range:7.0-25.1),and the follow-up time was 26.3 mo(range:12.8-40.1).All patients had delayed diagnosis,and 3patients had progressed to end-stage renal disease by the time they were diagnosed.Two patients received preemptive LT;their estimated glomerular filtration rate was maintained at>120 mL/min/1.73 m2,indicating a better prognosis.Three patients received sequential liver and kidney transplantation.After transplantation,serum and urinary oxalate decreased,and liver function recovered.At the last follow-up,the estimated glomerular filtration rates of the latter 3 patients were 179,52 and 21 mL/min/1.73 m2.CONCLUSION Different transplantation strategies should be adopted for patients based on their renal function stage.Preemptive-LT offers a good therapeutic approach for PH1.

Role of virtual reality in improving the spatial perception of the kidney during flexible ureteroscopy:A feasibility study using virtual reality simulators and 3D models

Background:The aims were to describe a software-based reconstruction of the patient-specific kidney cavity intraluminal appearance via a head-mounted device and to estimate its feasibility for training novices.Materials and methods:In total,15 novices were recruited.Each novice was shown a three-dimensional reconstruction of a patient's computed tomography scan,whose kidney was printed.They then joined the surgeon in the operating room and assisted them in detecting the stone during flexible ureteroscopy on the printed model.Then,each participant did a 7-day virtual reality(VR)study followed by virtual navigation of the printed kidney model and came to the operating room to help the surgeon with ureteroscope navigation.The length of the procedure and the number of attempts to find the targeted calyx were compared.Results:With VR training,the length of the procedure(p=0.0001)and the number of small calyces that were incorrectly identified as containing stones were significantly reduced(p=0.0001).All the novices become highly motivated to improve their endourological skills further.Participants noticed minimal values for nausea and for disorientation.However,oculomotor-related side effects were defined as significant.Five specialists noticed a good similarity between the VR kidney cavity representation and the real picture,strengthening the potential for the novice's education via VR training.Conclusions:Virtual reality simulation allowed for improved spatial orientation within the kidney cavity by the novices and could be a valuable option for future endourological training and curricula.

Indications and contraindications for shock wave lithotripsy and how to improve outcomes

For over 35 years shock wave lithotripsy has proven to be an effective,safe and truly minimally invasive option for the treatment of nephrolithiasis.Various technical factors as well as patient selection can impact the success of the procedure.We used published work focusing on outcomes of shock wave lithotripsy,risk of complications,and strategies for improving stone fragmentation to create this review.Multiple patient and technical factors have been found to impact success of treatment.Skin to stone distance,stone density and composition,size and location of the stone within the urinary system all influence stone free rates.A slower rate with a gradual increasing voltage,precise targeting,proper coupling will improve stone fragmentation and decrease risk of complications.The selection of appropriate patients through a shared decision making process and attention to the technical factors that improve stone free rates is key to providing an effective treatment and patient satisfaction.

Role of insulin resistance in uric acid nephrolithiasis

Metabolic syndrome has been implicated in the pathogenesis of uric acid stones.Although not completely understood,its role is supported by many studies demonstrating increased prevalence of uric acid stones in patients with metabolic syndrome and in particular insulin resistance,a major component of metabolic syndrome.This review presents epidemiologic studies demonstrating the association between metabolic syndrome and nephrolithiasis in general as well as the relationship between insulin resistance and uric acid stone formation,in particular.We also review studies that explore the pathophysiologic relationship between insulin resistance and uric acid nephrolithiasis.

改良经皮肾输尿管镜钬激光碎石术治疗复杂肾结石

【目的】探讨改良钬激经皮肾输尿管镜碎石术（PCNL）治疗复杂肾结石的有效性及安全性。【方法】回顾性分析42例钬激光PCNL治疗复杂肾结石患者，上盏肾穿刺、单通道，钬激光碎石。其中鹿角铸形结石16例，多发或巨大肾结石26例，结石长径1．8～4．2cm，术后放置F5～F7的双J管和留置F16的肾造瘘管。【结果142例手术均顺利完成，无中转开放手术。术中出血平均160（35±220）mL。平均手术时间为27～154（51．3±20．6）min。一次取净结石32例，二次取净结石7例，3例残留结石患者术后需行体外冲击波碎石（ESWL），术中、术后无严重并发症。1个月后复查肾输尿管膀胱平片，提示39例肾结石患者结石排净，3例结石残留，总取净率92．8％。术后并发出血21例，19例经输血等保守治疗治愈，2例经介入治疗痊愈。患者肾造瘘管留置5～10d，平均（4士2．2）d；平均住院时间（7．5±4。6）d。随访3个月无患侧腰或及腹部疼痛不适或肉眼血尿。【结论】改良钬激光PCNL治疗复杂肾型结石是治疗复杂肾结石较理想的方法。

尿石清冲剂对上尿路结石ESWL后治疗作用的研究

【目的】探讨尿石清颗粒冲剂对上尿路结石体外冲击波碎石 (ESWL)后的协同排石、预防并发症与复发的作用。【方法】将 32 8例上尿路结石患者ESWL后分为治疗组 1 72例和对照组 1 5 6例 ,治疗组给予口服尿石清颗粒冲剂和一般治疗 ,对照组仅予一般治疗。【结果】治疗组加服尿石清颗粒后治愈率为 86 .0 5 % ,明显高于对照组 (6 9.87% ) ,两组相比差异有非常显著性 (P <0 .0 1 ) ;复发率为 2 .6 8%明显低于对照组(8.91 % ) ,两组相比差异有显著性 (P <0 .0 5 )。而治疗组石街形成率 (0 .5 8% )和肾绞痛发生率 (1 .1 6 % )也低于对照组 (4 .4 9% )和 (5 .1 3% ) ,两组相比差异均有显著性 (P <0 .0 5 )。【结论】采用尿石清颗粒治疗ESWL术后患者 ,能提高治愈率。

超声引导下侧卧位经皮肾穿刺气压弹道联合超声碎石清石术治疗复杂性肾结石

【目的】探讨超声引导下侧卧位经皮肾穿刺气压弹道联合超声碎石清石术治疗复杂肾结石的疗效和安全性。【方法】2009年6月至2012年6月本院收治的236例复杂性肾结石患者，均在B超引导下，采用侧卧住经皮肾穿刺气压弹道联合超声碎石清石术治疗。【结果】平均手术时间（89士25）min，平均出血量（106±18）mL，平均住院时间（10．3±1．9）d，结石一次取净率79．2％，两次手术结石总取净率97．0％，无严重并发症发生。【结论】超声引导下侧卧位经皮肾穿刺气压弹道联合超声碎石清石术是治疗复杂肾结石的安全有效的方法，术中B超检查有利于结石定位穿刺、残留结石的检出和清除。

同期微创经皮肾穿刺取石术治疗双侧上尿路结石的疗效观察

【目的】探讨同期微创经皮肾穿刺取石术治疗双侧上尿路结石的临床疗效。【方法】回顾分析本院2006年3月至2011年12月住院的960例上尿路结石患者中65例双侧上尿路结石的临床资料，所有病例均应用同期微创经皮肾穿刺取石术治疗。【结果]59例一次取石成功，结石清除率为91．5％（54／59）。平均手术时间62．3min，术中血红蛋白平均下降2．1g／L，平均住院时间7d，术后发热8例，肾造瘘管疼痛需镇痛治疗4例。【结论】同期微创经皮肾穿刺取石术治疗双侧上尿路结石安全、有效。

超声引导下经皮肾镜钬激光碎石术治疗孤立肾上尿路结石

【目的】探讨超声引导下经皮肾镜碎石术治疗孤立肾上尿路结石的疗效。【方法】2010年8月至2012年11月，对23例孤立肾上尿路结石患者采用在超声引导下经皮肾镜钬激光碎石术治疗。【结果】23例患者中有20例术后复查无结石残留，平均住院时间7．1（4～16）d，16例肾功能不全患者中，术后14例肾功能恢复正常，2例血肌酐较术前明显下降，无大出血发生。【结论】超声引导下经皮肾镜钬激光碎石术治疗孤立肾上尿路结石安全有效。

输尿管镜下钬激光碎石术治疗输尿管结石623例

【目的】探讨输尿管镜下钬激光碎石术治疗输尿管结石的临床效果。【方法】2005年2月至2007年4月应用输尿管镜下钬激光碎石术治疗623例输尿管结石。【结果】552例手术成功,未见严重的并发症。【结论】输尿管镜下钬激光碎石术治疗输尿管结石疗效明确、安全。

多方位体外冲击波碎石术治疗较大单纯肾盂结石疗效分析

[目的]提高体外冲击波碎石术（ESWL）治疗较大肾结石的疗效.[方法]86例结石长径为（2.0～2.5）cm单纯肾盂结石患者随机接受多方位（M组）和单方位（S组）ESWL治疗,各方位治疗43例.观察、比较2个方位组的治疗次数、冲击数、需特殊处理的输尿管石街和ESWL后 3个月结石排净率.[结果]治疗次数,M组[（1.65±0.61）次]少于S组[（2.21±0.64）次]（P〈0.01）;每个患者的冲击数,M组[（3 942±1571）次]少于S组[（5 384±1650）次]（P〈0.01）;需特殊处理的石街,M组（20.9%）低于S组（41.9%）（P〈0.05）;结石排净率,M组（88.4%）高于S组（69.8%）（P〈0.05）.[结论] ESWL治疗较大单纯肾盂结石,采取多方位冲击是减少并发症和提高疗效的一种有效方法.

11例成人先天性巨输尿管合并输尿管结石的诊治

【目的】探讨成人先天性巨输尿管合并输尿管结石的诊治方法。【方法】总结11例成人先天性巨输尿管合并输尿管结石患者的病历资料,其中左侧5例,右侧4例,双侧2例。11例中行肾输尿管切除术、输尿管镜弹道碎石术(URL)各2例;行输尿管膀胱吻合术7例,其中先行肾造瘘术,二期行输尿管膀胱吻合术3例。【结果】URL成功1例,输尿管膀胱吻合术者全部成功。【结论】治疗此病原则是取尽结石,解除梗阻,尽量保留肾功能。理想的手术方式是输尿管膀胱吻合术。

微创双导管超声碎石治疗复杂性肾结石

【目的】总结cyberwand（双导管超声）经皮肾镜碎石（PCNL）治疗复杂性肾结石的治疗经验，探讨超声引导下PCNL治疗肾结石的方法、疗效和安全性。【方法】回顾本院2010～2011年超声引导下采用美国cYBERWAND双导管超声碎石清石系统治疗5l例肾结石患者（铸型结石46例、马蹄肾并结石2例、孤立肾肾结石3例）的临床资料，对手术时间、结石清除率、手术并发症等临床资料进行分析。【结果】平均结石直径（4．3±1．6）cm，建立通道时间10～28rain，平均15rain，手术时间45～110rain，平均60rain，一次性清石率82．3％（42／51），发热4例，1例达40℃以上，其余均低于38℃，2例因大量出血行介入栓塞治疗后治愈，1例出现大量胸腹腔积液于术中发现及时行胸腹腔引流后治愈。【结论】B超引导下经皮肾镜Cyberwand双导管超声碎石清石系统治疗肾铸型结石，具有结石清除率高、手术时间短、出血少、并发症少等优点，是治疗体积较大、多发性、鹿角性及铸型等复杂肾结石的理想方法，但对处理坚硬结石存在局限性。

超选择肾动脉栓塞治疗经皮肾镜取石术后肾动脉出血的疗效

【目的】探讨超选择性肾动脉栓塞治疗经皮肾镜取石术（PCNL）后并发肾动脉出血的临床应用价值。【方法】对38例PCNL后并发肾动脉出血的患者行超选择性肾动脉造影，诊断明确后行栓塞治疗。分析肾动脉造影表现、栓塞疗效及对肾功能的影响等。【结果】肾动脉造影显示34例单纯肾段以下肾小动脉损伤，2例形成动一静脉瘘；2例形成假性动脉瘤。38例患者经超选择插管栓塞后均能有效止血。栓塞范围测定平均为14．64％。所有患者肾功能未受影响，无严重并发症。【结论】超选择性肾动脉造影和栓塞术创伤小，见效快，可明确诊断并有效治疗PCNL术后并发的肾动脉出血，最大限度的保留患者的肾功能。