一期多通道标准肾镜取石术治疗复杂性肾结石

目的：评价F24标准通道经皮肾镜取石术（standard tract percutaneous nephrolithotomy，SPCNL）一期多通道治疗复杂性肾结石的安全性与临床疗效。方法：回顾性分析2008年6月～2010年8月采用一期多通道SPCNL治疗复杂性肾结石患者52例。结果：52例患者均一期成功建立经皮肾通道，双通道43例，三通道7例，四通道2例。无肾切除、腹腔脏器损伤等严重并发症发生。平均手术时间103min，一期结石取净38例（73．1％）。4例接受二期SPCNL，取净3例；2例接受输尿管镜气压弹道碎石术，均取净；9例接受ESWL。术后随访1～12个月，原残留结石9例中结石清除7例。结论：一期多通道SPCNL治疗复杂性肾结石安全有效，可选择性作为理想的治疗方案。     

经皮肾镜气压弹道联合超声碎石清石术治疗38例肾结石

目的探讨经皮肾镜气压弹道联合超声碎石术治疗肾结石的临床疗效。方法2006年3月-2006年12月，采用B超引导穿刺建立皮肾通道、肾镜下气压弹道联合超声碎石术治疗38例肾结石。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38例患者均Ⅰ期成功建立皮肾通道，其中35例Ⅰ期碎石清石，3例因结石巨大而分Ⅱ期碎石清石。平均住院8（5-18）d；手术时间为（87±23）min，结石处理时间为（59±17）min；平均失血量为（81±31）mL，全部患者不需要输血；碎石成功率为100％，Ⅰ期结石清除率为78．95％（30／38），Ⅱ期结石清除率为84．21％（32／38），6例术后辅助ESWL碎石，总结石清除率为92．11％（35／38）。术中1例因扩张过深致肾穿孔，未出现与碎年石器相关的并发症。结论经皮肾镜气压弹道联合超声碎石术治疗肾结石操作简单、安全可靠、疗效满意。     

微通道和标准通道PCNL治疗复杂性肾结石的比较

目的探讨与评价微通道和标准通道经皮肾镜碎石取石术（PCNL）两种方法治疗复杂性肾结石的安全性和临床疗效。方法我们采用标准通道（22F）和微通道（18F）PCNL治疗复杂性。肾结石49例,并记录碎石取石时间,结石取净率及手术并发症。结果49例患者均Ⅰ期成功建立经皮肾通道,标准通道组21例中,17例Ⅰ期碎石取石成功,4例行Ⅱ期碎石,平均碎石手术时间为（75±25）min。微通道组28例中,18例Ⅰ期手术成功,10例行Ⅱ期碎石,碎石时间为（92±31）min,两组比较有显著性差异（P〈0．05）;术后检测血红蛋白（Hb）,标准通道组20例（20／21）Hb下降〈30g／L,微通道组26例（26／28）Hb下降〈30g／L,两组比较无显著性差异（P〉0．05）;标准通道组结石清除率85．7％（18／21）,微通道组82．2％（23／28）,两组比较无显著性差异（P〉0．05）。结论标准通道和微通道PCNL治疗复杂性。肾结石疗效确切,均具有损伤小、恢复快、结石清除率高,并发症少等优点,但采用标准通道能缩短取石时间,两者结合效果更好。     

超声引导下经皮肾镜取石术治疗复杂性肾结石的回顾性分析：附113例报告

目的探讨超声引导下经皮肾镜治疗复杂性肾结石的方法、疗效,进一步提高结石清除率,降低并发症。方法回顾性分析采用超声引导经皮肾镜气压弹道超声碎石治疗113例（单侧肾结石为83例,双侧肾结石为30例）复杂性肾结石患者的临床资料,通过分析结石大小与手术时间、失血量,手术时间与失血量等数据,对手术操作方法、结石清除率、并发症等进行评价及总结。结果113例复杂性肾结石中93例为一期取净结石,一次性清除率达82．3％。平均手术时间78±34min（45—150）,失血量85±15．4ml（20～125）。术中未见严重并发症。结石大小与手术时间、失血量,手术时间与失血量之间均存在明显的线性相关关系（r=0．871,0．796,0．801,P〈0．05）。结论超声引导经皮肾镜气压弹道超声碎石技术具有高效、安全等优点,在治疗复杂性肾结石方面有良好的应用价值;同时,根据结石特点设计合理的操作通道,缩短手术时间,能有效避免并发症的发生。     

联合不同口径多通道经皮肾镜取石术治疗复杂性肾结石

目的探讨联合微通道及标准通道进行多通道经皮。肾镜取石术（percutaneous nephrolithotomy,PCNL）治疗复杂性肾结石的临床疗效和安全性。方法2008年1月～2013年2月,采用联合微通道及标准通道进行多通道PCNL术治疗复杂性肾结石121例。包括鹿角形肾结石73例,肾多发结石48例。合并脓肾31例。结果121例共建立281个通道。其中一期单通道36例,双通道70例,三通道15例;二期手术56例,其中49例新建通道60个。手术时间34～127min,平均72min。结石总清除率90．9％（110／121）。术后无严重并发症。结论联合不同口径多通道PCNL治疗复杂性肾结石安全有效,清石率高,并发症低,住院周期短,可作为一种理想的治疗术式。     

多通道微创经皮肾镜治疗复杂性肾结石

目的探讨F18～F20多通道微创经皮肾镜取石术治疗复杂性肾结石的安全性与有效性。方法 2004年1月～2011年5月对67例复杂性肾结石行多通道微创经皮肾镜治疗。先取截石位,向患侧肾盂逆行留置F5输尿管导管后改为俯卧位,上腹部垫薄枕。C形臂X线定位后,在腋后线到肩胛下线之间取第10肋间以下最接近肾盏并能沿肾盏指向肾盂方向的穿刺点,18 G肾穿刺针穿入后组肾盏内逐级扩张后留置peel-away鞘建立通道,置入微创肾镜,直视下气压弹道碎石,利用灌注水流及输尿管导管注水将碎石冲出,稍大的结石可钳夹取出。术中X线透视了解结石残留情况,按上述方法进行多通道穿刺目标肾盏进行碎石,尽可能一期取净结石。结果 65例建立2个通道,2例建立3个通道。手术时间50～120 min,平均93 min;术中出血量15～200 ml,平均30 ml。一期取净结石55例,二期取净结石7例,结石清除率92.5%（62/67）。术后住院时间3～10 d,平均7 d。术后发生感染8例（11.9%）,经头孢类抗感染药物及药敏培养选择抗感染药物治疗后,感染控制良好,7例治愈出院,1例尿培养证实为热带假丝酵母菌,拔除内支架后口服氟康唑（400 mg,qd）2周治愈。术后6 h活动性动脉出血1例,在DSA下行超选择肾动脉栓塞术后顺利止血。急性肾功能衰竭1例,通过3次血液透析,渡过少尿期后康复出院。结石残留5例,通过放置支架管后行体外碎石治疗,3例结石排出,2例无效。45例随访1～7年,平均5年,42例无结石残留,3例结石复发,其中1例2年复发,2例3年复发。结论多通道微创经皮肾镜治疗复杂性肾结石结石清除率较高,并发症低,经济方便,可作为较大复杂性肾结石治疗的首选方法。     

多通道微造瘘经皮肾输尿管镜钬激光碎石术治疗复杂肾结石

目的 评估多通道微造瘘经皮肾输尿管镜钬激光碎石或气压弹道术碎石术治疗复杂肾结石的安全性和有效性.方法 回顾分析2001年到2009年间利用多通道微造瘘经皮肾输尿管镜钬激光碎石术或气压弹道碎石治疗复杂肾结石58例患者的临床资料.结果 58例患者共62个肾脏接受微造瘘经皮肾输尿管镜碎石术,共建立130条经皮肾通道,最多3个通道,一般仅为2个.58%的通道建立在第11肋间,其余分别位于第12肋下或第10肋间.12例患者术中术后需输血,5例患者出现感染性休克.48例患者经多期手术结石完全清除,清除率达77.4%.结论 多通道经皮肾镜取石术安全、有效,是复杂肾结石的治疗方式之一.     

多期多通道经皮肾镜取石术治疗完全性鹿角形结石

目的研究多期多通道经皮肾镜取石术(PNL)治疗完全性鹿角形结石的安全性及有效性。方法回顾性分析了本院2012年3月至2014年9月接受PNL治疗的完全性鹿角形肾结石患者的临床资料,共35例,双侧鹿角形结石5例,单侧30例,鹿角形结石共40枚。结果 40枚完全性鹿角形结石共穿刺126条通道,平均3.15条/枚。共行PNL术85期,平均2.1期/枚。手术时间76~260分钟,平均(96.2±14.5)分钟。结石清除率87.5%。输血2例,胸膜损伤1例,无其他严重并发症。术后平均住院时间(7.8+1.21)天。结论多期多通道经皮肾镜取石术治疗鹿角形结石安全可行,疗效确切,具有创伤小、恢复快、可反复操作等优点。     

经皮肾镜下气压弹道碎石联合超声碎石术治疗复杂性肾结石疗效观察

目的：评价经皮肾镜下气压弹道碎石联合超声碎石术处理复杂性肾结石的疗效。方法：自2003年9月～2004年4月采用经皮肾镜下气压弹道碎石联合超声碎石术Ⅰ期治疗肾结石38例42侧。结果：平均手术时间85min，结石处理时间62min，结石清除率88．1％；5例多发性结石或铸形结石患者经皮通道小角度的肾盏内有直径小于1cm结石残留，辅助施行体外冲击波碎石治疗。随访1～3个月，无严重手术并发症。结论：经皮肾镜下气压弹道碎石联合超声碎石术处理大的复杂性肾结石具有高效、安全的特点，结石清除率高，值得临床推广应用。     

多通道微创经皮肾镜取石术治疗复杂性肾结石的效果观察

目的探讨多通道微创经皮肾镜取石术治疗复杂性肾结石的效果。方法将2014-01—2015-12间治疗的198例复杂性肾结石患者根据治疗方式不同分为2组。单通道组(96例)行单通道微创经皮肾镜取石术,多通道组(102例)行多通道微创经皮肾镜取石术。比较2组患者手术情况、Ⅰ期和Ⅱ期结石清除率及术后并发症发生率。结果 2组患者手术时间、术中出血量及住院时间比较差异无统计学意义(P0.05)。多通道组患者Ⅰ期和Ⅱ期结石清除率明显高于单通道组,术后并发症发生率低于单通道组,差异均有统计学意义(P0.05)。结论多通道微创经皮肾镜取石术治疗复杂性肾结石,能提高结石清除率及降低术后并发症发生率。     

Minimally invasive percutaneous nephrolithotomy for staghorn calculi: a novel single session approach via multiple 14-18Fr tracts

OBJECTIVE: To report our experience with minimally invasive percutaneous nephrolithotomy (MPCNL) (14-18Fr percutaneous tract) to treat staghorn calculi via multiple percutaneous tracts in a single session procedure, and evaluate the feasibility and efficiency of this technique. PATIENTS AND METHODS: From March 2001 to November 2005, 100 patients with staghorn calculi were treated by MPCNL via multiple percutaneous tracts. The size and location of the stone, operative parameters, number of tracts, stone-free rate, operating time, hospital stay, and complications were analyzed retrospectively. RESULTS: A total of 209 percutaneous tracts were established in 100 renal units during 128 operations including 28 second-look procedures. The mean operating time was 107 minutes (range 43 to 130 min) and the mean hospital stay was 9.4 days (range 6 to 13 d). The initial stone clearance rate of 72% after the first session was improved to 93% after a second-look procedure in 28 patients. The mean blood loss was 112 mL (range 64 to 483 mL), 3 patients required blood transfusion and 1 patient with branched renal arterial injury during puncture received a highly elective embolism. Seven patients had a postoperative fever of 38.5 degrees C or greater, whereas 4 patients had mild hydropneumothorax. CONCLUSIONS: With the development of instrument and increased experience, judiciously made multiple percutaneous tracts in a single session MPCNL for treating staghorn calculi in selected cases is safe, feasible, and efficient with an acceptable morbidity.     

经皮肾镜超声弹道碎石术治疗复杂性肾结石

目的：探讨经皮肾镜超声弹道碎石术治疗复杂性肾结石的疗效。方法：采用经皮肾镜联合EMS Ⅲ代超声弹道碎石清石系统治疗48例复杂性肾结石患者,完全性鹿角状结石12例,部分鹿角状结石30例,多发性结石6例。结石直径2．0～6．5cm,平均2．8cm。结果：48例患者中,43例Ⅰ期取净结石;5例完全性鹿角状结石者术后2个月仍有结石残留,结石直径均小于1．0cm,辅助施行ESWL后排净。结石粉碎率100％,结石清除率89．6％（43／48）。手术时间50～120min,平均70min,平均出血量50ml。无严重并发症发生。术后随访3～6个月,肾功能均有不同程度改善。结论：经皮肾镜下使用EMSⅢ代碎石清石系统治疗复杂性肾结石,具有高效、可靠、安全、损伤小、出血少及恢复快等优点,可以作为目前治疗复杂性肾结石的首选方法。     

Minimally invasive percutaneous nephrolithotomy with multiple mini tracts in a single session in treating staghorn calculi

There has been continuing controversy regarding multiple tracts in a percutaneous nephrolithotomy (PCNL) session that may bring more complications, especially severe bleeding need for transfusion, even nephrectomy. Little tracts may bring less trauma to renal parenchyma than standard PCNL tracts. We carried minimally invasive PCNL (MPCNL) in treating staghorn calculi with multiple 16Fr percutaneous tracts in a single session, in an attempt to get high stone free with little trauma, and compared the morbidity of standard PCNL procedures in a prospective trial. A total of 54 consecutive patients with staghorn calculi were prospectively randomized for MPCNL (29) and PCNL (25). The size and location of stone, operative parameters, number of tracts, stone-free rate, operating time, hospital stay and complications were analyzed. In MPCNL group, a total of 67 percutaneous tracts were established in 29 renal units, while 28 tracts in 25 renal units in PCNL group. Compared to PCNL, MPCNL was associated with higher clearance rate (89.7 vs. 68%, p = 0.049), less chance need for adjunctive procedure of SWL or second-look PCNL (24.1 vs. 60%, p = 0.007), while a similar complication rate (37.9 vs. 52%, p = 0.300). In conclusion, with the development of instruments and increased experience, judiciously made multiple percutaneous tracts in a single session of MPCNL for treating staghorn calculi were safe, feasible and efficient with an acceptable morbidity.     

Multiple tracts percutaneous nephrolithotomy assisted by LithoClast master in one session for staghorn calculi: report of 117 cases

The objective of the study is to evaluate the safety, efficacy and outcome of multiple tracts percutaneous nephrolithotomy (PCNL) assisted by LithoClast master (the third-generation Electro Medical System) in one session for the treatment of staghorn calculi. From October 2011 to March 2013, 117 patients with staghorn calculi underwent multiple tracts PCNL in our hospital. The combined pneumatic and ultrasonic powered lithotripter (EMS LithoClast master) was used to fragment and remove the calculi. The data were retrospectively analyzed with regard to stone burden, number of tracts, operation time, total operative blood loss, postoperative hospital stay, complications rate, and stone clearance rate. A total of 142 renal units in 117 patients (63 men and 54 women) were treated. Of the 142 renal units, 77 (54.2 %) had complete staghorn calculi, and 65 (45.8 %) had partial staghorn calculi. A total of 416 tracts were established in the 142 renal units. The mean number of tracts used in a single renal unit was 2.8 (range 2–4), most required three tracts. The mean (range) operating time is 72 (55–130) min. The mean (range) duration of postoperative hospital stay is 5.5 (3–9) days. Mean estimated operative blood loss is 150 (60–350) mL. The complications included blood transfusion in 9 (7.7 %) patients, high fever in 12 (10.3 %), sepsis in 5 (4.3 %), hydrothorax in 4 (3.4 %), and pseudoaneurysm in 3 (2.6 %). A complete stone clearance rate of 87.2 % (102/117) was achieved after one session of PCNL. This rate increased to 94.0 % after a secondlook procedure. In conclusion, multiple tracts PCNL assisted by EMS LithoClast master in one session is safe and effective in achieving a great stone clearance rate with acceptable morbidity for the treatment of staghorn calculi.     

瞬时X线联合B超在复杂经皮肾镜取石术中的应用体会

目的:探讨瞬时X线联合B超引导经皮肾穿刺定位在较为复杂的经皮肾镜取石术(PCNL)中的应用价值。方法:回顾2012年3月~2013年10月我院收治的69例肾结石患者临床资料,其中肾脏轻度积水25例,肾脏旋转不良12例,肾脏无明显积水8例,完全鹿角形结石6例,重复肾6例,术中逆行造影及人工积水肾建立失败4例,肾结石术后瘢痕肾5例,肥胖患者2例,肾下垂患者1例。术中常规给予输尿管置管行逆行造影并建立人工积水肾,采用C型臂瞬时X线照相联合B超引导建立经皮肾穿刺通道。结果:69例患者均穿刺成功,建立F14~18通道,建立时间10~35min,术中X线暴露次数2~5次。其中肾脏轻度积水25例、肾脏无明显积水8例、完全鹿角形结石6例由间断瞬时X线定位为主,辅助B超定位以避开主要血管及领近器官或辅助建立多通道;肾脏旋转不良12例、重复肾6例、肾结石术后瘢痕肾5例、肥胖患者2例、肾下垂患者1例由B超定位为主,辅助瞬时X线定位以确保穿刺线通过肾盏穹窿部;术中逆行造影及人工积水肾建立失败4例,由B超定位穿刺针进入肾脏集合系统,经穿刺针推注造影剂显示肾盂肾盏,用第二穿刺针在瞬时X线定位下建立目标肾盏的穿刺通道。64例为Ⅰ期手术,5例行Ⅱ期手术,清石率为96.8%,无严重并发症发生。结论:对于较为复杂的PCNL,瞬时X线联合B超的定位技术能够结合两种定位方法的优势,建立安全、有效的穿刺通道,提高清石率,减少手术并发症的产生,同时减少患者及医生在手术中X线的暴露时间。     

Percutaneous nephrolithotomy for complex caliceal calculi and staghorn stones in children less than 5 years of age

BACKGROUND AND PURPOSE: Treatment of children with staghorn and complex caliceal calculi is one of the most challenging problems in urology. We present our experience with percutaneous nephrolithotomy (PCNL) monotherapy for staghorn and complex caliceal calculi in children less than 5 years of age. PATIENTS AND METHODS: Between 1991 and 2004, 27 boys and 9 girls aged 11 months to 4.5 years underwent PCNL for staghorn (33%) or complex caliceal (67%) calculi. The average bulk of the stones was 140.17 +/- 42.16 mm(2) (range 61-253 mm(2)). Staging of the procedure was preferred in children with renal insufficiency, urinary-tract infection, fragmentation time >60 minutes, or a stone burden requiring more than two tracts. Essential steps of the technique were a dynamic contrast study to select the appropriate-size Amplatz sheath and ultrasound guidance for renal access. RESULTS: The average operative time was 72.11 +/- 28.86 minutes. The stone-free rate was 86%, the mean hemoglobin drop was 2.2 +/- 0.95 g/dL, and the mean hospital stay was 3.5 days. Less than half of the patients (42%) were treated in a single stage, the remainder requiring multiple procedures. Only 39% could be treated with a single tract. There was statistically significant increase in the blood loss in patients requiring multiple tracts (P = 0.008); however, staging the procedure did not increase the blood loss (P = 0.06). CONCLUSION: Percutaneous nephrolithotomy is safe and effective in children less than 5 years of age. Staging the procedure, instrument modification, the timed "multi mini-perc" technique, and ultrasound-guided access help in achieving maximum stone clearance with minimal morbidity.     

微创经皮肾取石术治疗孤立肾铸型结石的疗效观察

目的：探讨微创经皮肾取石术（MPCNL）治疗孤立肾铸型结石的安全性及有效性。方法：回顾性分析2007年4月-2008年12月应用MPCNL治疗34例孤立肾铸型结石患者的临床资料：34例患者结石平均表面积（2314±179）mm^2,肾积脓5例。4例先行穿刺造瘘术,5～7天后行二期经皮肾镜取石术,其余患者均行一期取石术。其中单通道取石18例,双通道取石15例,三通道取石1例。结果：3例一期取石时残余小结石,结合ESWL清除小残石,结石总清除率为91．2％（31／34）。1例出现感染性休克,1例术后大出血行介入栓塞治疗,无死亡患者。术后随访4～18个月,19例肾功能不全患者中,11例肾功能恢复正常,6例肾功能有不同程度改善,2例发展为尿毒症期行血液透析,其中1例为术后大出血行介入栓塞的患者。结论：微创多通道MPCNL治疗孤立肾铸型结石安全可行,效果确切,具有创伤小、恢复快、可反复操作等优点,可作为孤立肾铸型结石的首选治疗方法。     

微创经皮肾穿刺取石术治疗肾结石

目的：探讨微创经皮肾穿刺取石术(微创PCNL)治疗肾结石的疗效。方法：采用微创PCNL治疗的235例肾结石患者，肾结石长径为1．5～1．7cm，单发性结石150例，多发性结石85例。其中鹿角状结石60例，双侧肾结石40例，孤立肾并肾结石9例，有开放手术史23例。结果：235例均行一期穿刺取石，其中1次取石183例，2次以上取石52例；单通道取石198例，多通道取石37例，结石清除率85％。手术时间平均2h；术中、术后有明显出血7例(3％)，均经保守治疗治愈，平均住院时间10d。结论：微创PCNL是一种有效的治疗肾结石的方法，创伤小，恢复时间短。     

Percutaneous nephrolithotomy requiring multiple tracts: comparison of morbidity with single-tract procedures

PURPOSE: To compare the morbidity of percutaneous nephrolithotomy (PCNL) requiring multiple percutaneous tracts with that of procedures requiring a single tract for calculus clearance. PATIENTS AND METHODS: Data from 20 patients undergoing PCNL through two or more percutaneous renal tracts over a 1-year period were compared with a contemporary cohort of 20 patients undergoing PCNL requiring a single tract. The mean stone size was 2157 mm(2) v 423 mm(2) (P < 0.0001), the baseline serum creatinine concentration was 1.67 mg/dL v 1.13 mg/dL (P < 0.05), and the baseline hemoglobin concentration was 11.8 g/dL v 13.4 g/dL (P < 0.05) in the multiple- and single-tract groups, respectively. RESULTS: All single-tract and 95% of multiple-tract patients were rendered stone free. The mean drop in hemoglobin was similar in the two groups (2.3 g/dL for single tract v 2.1 g/dL for multiple tracts; P = 0.55). Complications occurred in two patients in each group. Four multiple-tract patients required blood transfusion. The need for transfusion correlated with lower preoperative hemoglobin and higher preoperative serum creatinine. There was a significant rise in serum creatinine (1.67 mg/dL to 1.91 mg/dL; P < 0.05) and drop in creatinine clearance (76.9 mL/min to 67.2 mL/min; P < 0.05) in the multiple-tract group; this was more pronounced in patients with existing renal insufficiency. No significant change in renal function was seen in the single-tract group. CONCLUSIONS: Monotherapy with PCNL utilizing multiple percutaneous tracts is highly effective in the treatment of staghorn and other large-volume renal calculi. Blood loss and complication rates with such an aggressive approach are comparable to those of PCNL incorporating a single percutaneous tract for more straightforward calculi.     

Percutaneous nephroscopic with holmium laser and ultrasound lithotripsy for complicated renal calculi

The aim of this work is to validate the clinical efficacy of the high-power holmium:YAG laser with percutaneous nephrolithotripsy (PCNL) in combination with ultrasound lithotripsy for complicated renal calculi. From November 2006 to December 2007, 60 patients with complicated renal calculi were treated with PCNL, where an F24 standard renal access tract was established by percutaneous renal puncture under the guidance of B-mode ultrasound, and stones were fragmented and cleared by high-power holmium laser in combination with ultrasound under an F20.8 nephroscope. Of the 60 patients with complicated renal calculi, 20 were complete staghorn calculi and 30 were partial staghorn calculi, of which six patients were accompanied with renal insufficiency; two were solitary calculi, and eight were caliceal diverticular calculi. Calculi were removed by one attempt in 49 patients and by two attempts in 11 patients; through one tract in 50 patients and through two and three tracts in ten patients. The stone-free rate was 81.7%. No injury to the pleura and abdominal organs occurred during the intraoperative puncture. No postoperative blood transfusion was needed in any patient, nor did fever and secondary hemorrhage occur. The mean operation duration was 98 min (range, 60–150 min), and the mean lithotripsy time was 45 min (range, 30–85 min). Additional postoperative extracorporeal shock wave lithotripsy (ESWL) was performed on six patients. High-power holmium laser PCNL in combination with ultrasound lithotripsy is safe, effective, and minimally invasive, with a high stone-free rate, especially for complicated renal calculi.