1386 | 1Urology and Nephrology Research Center, Shohadae Ta- jrish Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 2 Department of Urology, Medical Laser Application Research Center, Shohadae Ta- jrish Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 3 Infertility and Reproduc- tive Health Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Hossein Karami,1 Mohammad Mohsen Mazloomfard,2 Aida Moeini,3 Mojtaba Mohammadhosseini,1 Alireza Rezaei,1 Behzad Lotfi2 Blind versus Fluoroscopy-guided Percuta- neous Nephrolithotomy: A Randomized Clinical Trial Corresponding Author: Mohammad Mohsen Mazloomfard, MD Urology and Nephrology Re- search Center, No.103, Boostan 9th St., Pasdaran Ave., Tehran, Iran. Tel: +98 21 22567222 Fax: +98 21 22567282 E-mail: mazloomfard@yahoo. com Received February 2012 Accepted January 2014 Purpose:‎Due‎to‎the‎negative‎impact‎of‎radiation‎on‎the‎patient‎and‎the‎surgical‎team‎during‎ percutaneous‎nephrolithotomy‎(PCNL),‎we‎aimed‎to‎evaluate‎success‎rate‎and‎complications‎ of‎blind‎access‎for‎PCNL‎using‎lumbar‎notch‎landmark‎and‎compare‎with‎conventional‎fluor- oscopy-guided access. Materials and Methods:‎In‎a‎clinical‎trial,‎100‎patients‎who‎were‎candidate‎for‎PCNL,‎were‎ randomly‎assigned‎into‎blind‎group‎(1)‎and‎fluoroscopy-guided‎group‎(2).‎In‎group‎1‎the‎lum- bar‎notch‎was‎used‎to‎guide‎percutaneous‎access‎and‎in‎group‎2‎fluoroscopy‎performed‎after‎ needle‎insertion,‎Amplatz‎placement‎and‎at‎the‎end‎of‎surgery.‎If‎the‎access‎failed,‎we‎would‎ repeat‎puncturing‎up‎to‎5‎times.‎In‎group‎2,‎access‎was‎achieved‎using‎full‎fluoroscopy‎guid- ance.‎All‎patients‎underwent‎postoperative‎assessment‎including‎kidney-ureter-bladder‎X-ray‎ and ultrasonography. Results:‎Both‎mean‎access‎time‎and‎mean‎operation‎time‎were‎statically‎similar‎in‎group‎1‎ and‎group‎2‎(3.3‎±‎0.5‎vs.‎3.6‎±‎0.7‎min‎and‎35.2‎±‎4.6‎vs.‎38.9‎±‎4.1‎min,‎respectively).‎A‎suc- cessful‎puncture‎was‎achieved‎in‎86%‎and‎94%‎of‎the‎patients‎in‎groups‎1‎and‎2,‎respectively‎ (P‎=‎.18).‎Total‎success‎rate‎of‎procedure‎was‎80%‎and‎88%‎of‎the‎patients‎in‎groups‎1‎and‎2,‎ respectively‎(P‎=‎.27). Conclusion:‎According‎to‎this‎study,‎it‎seems‎that‎blind‎access‎is‎a‎safe‎and‎effective‎PCNL‎ method,‎and‎we‎recommend‎employment‎of‎this‎technique‎by‎skilled‎endourologist‎in‎urology‎ centers‎especially‎for‎patient‎with‎large‎hydronephrotic‎kidney. Keywords:‎kidney‎calculi;‎surgery;‎nephrostomy;‎percutaneous;‎methods;‎endoscopy;‎litho- tripsy;‎adverse‎effects;‎postoperative‎complications;‎treatment‎outcome;‎fluoroscopy;‎prospec- tive‎studies.‎ ENDOUROLOGY AND STONE DISEASE Endourology and Stone Disease 1387Vol. 11 | No. 02 | March- April 2014 |U R O LO G Y J O U R N A L INTRODUCTION Percutaneous‎ nephrolithotomy‎ (PCNL)‎ has‎ im-proved‎the‎treatment‎of‎kidney‎calculi‎since‎its‎in-troduction‎in‎late‎1970s.(1)‎Because‎of‎its‎safety‎and‎ low‎incidence‎of‎complications,‎now‎PCNL‎is‎the‎treatment‎ of‎choice‎in‎patients‎with‎kidney‎calculi‎>‎2‎cm‎in‎diameter‎ and‎in‎whom‎extracorporeal‎shock‎wave‎lithotripsy‎(SWL)‎ has‎failed.(2) Although‎PCNL‎under‎fluoroscopy‎guidance‎is‎the‎routine‎ approach‎for‎accessing‎the‎pyelocaliceal‎system,‎other‎meth- ods‎such‎as‎computed‎tomography-guided‎(CT-guided)‎ac- cess‎and‎especially‎X-ray‎free‎approaches‎like‎ultrasonog- raphy-guided‎method‎have‎been‎employed‎recently‎in‎some‎ studies.(3-‎7)Because‎the‎adverse‎effects‎of‎radiation‎are‎not‎ dose‎dependent‎and‎shield‎protection‎is‎not‎complete,‎X-ray‎ should‎be‎used‎carefully‎in‎medical‎procedures‎and‎eliminate‎ in unnecessary protocols. All occupational personnel should ‘achieve‎as‎low‎as‎reasonably‎achievable’‎(ALARA)‎dose‎of‎ radiation.(8) According‎to‎our‎knowledge,‎there‎are‎only‎few‎studies‎re- porting‎blind‎access‎to‎pyelocaliceal‎system‎with‎acceptable‎ safety‎and‎efficacy‎and‎low‎radiation‎hazards‎to‎the‎patient‎ and‎the‎surgical‎team‎during‎PCNL.(9-12)‎This‎clinical‎trial‎is‎ a‎first‎study‎that‎compares‎the‎results‎and‎complications‎of‎ PCNL‎with‎blind‎access‎under‎full‎fluoroscopy‎evaluation‎ with‎conventional‎fluoroscopy-guided‎approach. MATERIALS AND METHODS Study Population Between‎January‎2005‎and‎October‎2010,‎a‎total‎number‎of‎ 100‎patients‎who‎were‎candidate‎for‎PCNL‎enrolled‎in‎the‎ study‎after‎a‎routine‎preoperative‎evaluation.‎The‎inclusion‎ criteria‎were‎either‎pelvic/pyelocaliceal‎stones‎larger‎than‎2‎ cm‎in‎diameter‎or‎impacted‎proximal‎ureteral‎stones‎larger‎ than‎1‎cm.‎The‎patients‎with‎kidney‎anomalies,‎uncontrolled‎ coagulopathies, single caliceal stones without hydronephro- sis‎and‎previous‎histories‎of‎PCNL‎or‎open‎renal‎stone‎sur- geries‎were‎excluded.‎The‎study‎protocol‎was‎explained‎to‎ each‎patient‎and‎informed‎consent‎was‎obtained.‎The‎study‎ was‎approved‎by‎the‎ethics‎committee‎of‎the‎Urology‎and‎ Nephrology‎Research‎Center.‎Preoperative‎evaluation‎con- sisted‎of‎tests‎such‎as‎urine‎analysis,‎urine‎culture‎and‎renal‎ function‎tests.‎Before‎PCNL,‎urine‎cultures‎were‎obtained,‎ and‎ if‎positive,‎antibiotics‎were‎administered.‎ Intravenous‎ urography‎was‎the‎primary‎imaging‎modality‎to‎determine‎ the‎size‎and‎location‎of‎calculi,‎the‎anatomy‎of‎the‎upper‎uri- nary‎tract,‎the‎degree‎of‎hydronephrosis,‎and‎the‎targeted‎ca- lyx.‎Prophylactic‎intravenous‎antibiotics‎were‎administered‎ before‎surgery.‎All‎procedures‎were‎performed‎by‎a‎single‎ surgeon‎who‎was‎experienced‎in‎PCNL. Study Design This‎was‎a‎single‎center‎[with‎balanced‎randomization‎(1:1)],‎ parallel-group‎study‎conducted‎in‎the‎urology‎department‎of‎ Shohadae‎Tajrish‎Hospital‎in‎Tehran,‎Iran.‎Patients‎were‎ran- domly‎assigned‎to‎one‎of‎two‎groups‎according‎to‎the‎method‎ of‎treatment:‎blind‎(group‎1,‎n =‎50)‎and‎fluoroscopy-guided‎ (group 2, n =‎50)‎PCNL‎groups.‎Simple‎randomization‎was‎ carried‎ out‎ using‎ computerized‎ random‎ numbers.‎ Sample‎ size‎was‎determined‎after‎consideration‎of‎type‎1‎statistical‎ error‎<‎5%;‎and‎type‎2‎statistical‎error‎<‎20%. Surgical Technique After‎induction‎of‎general‎anesthesia,‎an‎open‎ended‎5‎French‎ (F)‎ureteral‎catheter‎was‎inserted‎in‎the‎lithotomic‎position,‎ and then patient was repositioned into prone position with all pressure points padded. For‎patients‎in‎group‎1,‎the‎lumbar‎notch‎was‎used‎to‎guide‎ percutaneous access(13)‎which‎is‎bounded‎by‎the‎latissimus‎ dorsi‎muscle‎and‎the‎12th rib in the superior, by the sacrospi- nalis‎and‎ the‎quadratus‎ lumborum‎muscles‎ in‎ the‎medial,‎ and‎by‎the‎transverses‎abdominis‎and‎the‎external‎oblique‎ muscles‎laterally.(9) An 18-gauge access needle was inserted into‎the‎lumbar‎notch‎with‎an‎angle‎of‎30°‎to‎45°‎pointed‎ cephalad,‎and‎advanced‎to‎a‎depth‎of‎nearly‎4‎to‎6‎cm‎un- der the 12th‎ rib.‎Correct‎entrance‎ to‎ the‎collecting‎system‎ was assured when urine is withdrawn spontaneously or by syringe‎aspiration.‎For‎patients‎with‎a‎large‎pelvis‎and‎stag- horn‎stones,‎access‎was‎accomplished‎by‎touching‎the‎stones‎ by‎the‎needle.‎Fluoroscopy‎was‎used‎in‎this‎step‎to‎assess‎ the‎position‎and‎location‎of‎needle‎in‎ the‎calyx,‎and‎then‎ a‎guide‎wire‎was‎placed.‎The‎depth‎of‎insertion‎measured‎ precisely‎by‎ruler‎for‎next‎steps‎dilatation.‎The‎tract‎dilated‎ by‎telescopic‎dilators‎and‎then‎Amplatz‎sheath‎(28‎to‎30‎F)‎ inserted.‎During‎these‎steps,‎sterile‎water‎or‎normal‎saline‎ was injected into the ureteral catheter to increase the grade of‎hydronephrosis‎in‎order‎to‎out‎flowing‎of‎fluid‎from‎the‎ end‎of‎dilators‎or‎Amplatz‎sheath‎to‎prevent‎over-advance- Blind Access Percutaneous Nephrolithotomy | Karami et al 1388 | ment‎of‎them.‎Other‎fluoroscopy‎performed‎to‎estimate‎the‎ placement‎of‎Amplatz‎sheath.‎By‎using‎rigid‎nephroscope‎ and‎ Swiss‎ pneumatic‎ lithotripsy‎ (Swiss‎ Lithoclast;‎ EMS,‎ Angiomed,‎GmbH‎&‎Co.,‎Karlsruhe,‎Germany),‎stones‎were‎ fragmented‎and‎extracted‎by‎grasping‎forceps.‎At‎the‎end,‎ nephroscopy‎followed‎by‎a‎control‎fluoroscopy‎were‎carried‎ out‎for‎any‎residual‎stone‎detection‎and‎then‎Amplatz‎sheets‎ were‎removed‎and‎skin‎were‎sutured‎(tubeless‎procedure).‎ Maximum‎of‎5‎times‎puncturing‎was‎applied‎in‎case‎of‎no‎ urine‎drainage,‎and‎if‎it‎failed,‎the‎proper‎access‎was‎per- formed‎under‎fluoroscopic‎guidance.‎In‎group‎2,‎all‎standard‎ PCNL‎steps‎mentioned‎above‎including‎access‎to‎the‎collect- ing‎system‎performed‎under‎fluoroscopy‎guidance.‎ Outcome Assessment Due‎to‎the‎difference‎between‎two‎methods,‎it‎was‎not‎possi- ble‎to‎blind‎the‎surgical‎team‎from‎knowledge‎of‎which‎pro- cedure‎a‎participant‎received;‎however,‎after‎PCNL‎operation‎ the‎patients’‎evaluator‎was‎blind‎to‎the‎method‎of‎surgery.‎ Stone‎free‎status‎as‎the‎primary‎outcome‎measure‎was‎used‎ to‎evaluate‎the‎efficacy‎and‎residual‎stone‎burden‎was‎deter- mined‎by‎plain‎abdominal‎radiographs‎and‎renal‎ultrasound‎ studies‎routinely‎obtained‎48‎hours‎after‎treatment.‎The‎pro- cedure‎considered‎as‎a‎failure‎either‎in‎any‎stone‎residual‎ fragments‎detected‎by‎these‎studies‎or‎unsuccessful‎access. Demographic‎and‎stones‎characteristics,‎degree‎of‎hydrone- phrosis,‎time‎to‎access‎(from‎the‎start‎of‎puncturing‎to‎com- plete‎dilation),‎number‎of‎puncturing‎attempts,‎location‎of‎ access‎to‎the‎system,‎time‎of‎operation‎(from‎the‎induction‎ of‎anesthesia‎to‎last‎skin‎suture),‎hospitalization‎time,‎change‎ in‎hemoglobin‎level‎(preoperative‎and‎1‎day‎after‎surgery) and‎complications‎such‎as‎bleeding,‎uro-sepsis‎and‎collect- ing‎system‎perforation‎were‎compared‎between‎the‎2‎groups. Statistical Analysis Data‎analysis‎was‎performed‎using‎Student’s‎t‎test‎and‎chi- square‎ test.‎ The‎ statistical‎ package‎ for‎ the‎ social‎ science‎ (SPSS‎Inc,‎Chicago,‎Illinois,‎USA)‎version‎16‎was‎used‎for‎ analysis and P‎values‎lower‎than‎.05‎were‎accepted‎as‎sig- nificant. RESULTS After‎a‎routine‎preoperative‎evaluation,‎50‎patients‎in‎each‎ group‎were‎enrolled‎in‎this‎study.‎Demographic‎and‎clinical‎ characteristics‎of‎patients‎in‎each‎group‎are‎shown‎in‎Table‎ 1.‎A‎successful‎access‎achieved‎in‎43‎(86%)‎and‎47‎(94%)‎ Endourology and Stone Disease Table 1. Demographic and clinical characteristics of study patients. Variables Blind Fluoroscopy-Guided P Mean age (years) 30.3 ± 6.5 30.4 ± 7.8 .95 Male, no. (%) 31 (62) 32 (64) .84 Body mass index (kg/m2) 26.1 ± 4.3 26.7 ± 4.1 .48 Stone diameter (mm) 26.4 ± 5.1 25.8 ± 4.1 .52 Number of stones 1.3 ± 0.7 1.3 ± 0.6 .99 Stone location, no. (%) Superior ureter Pyelocalix Pelvic 9 (18) 14 (28) 27 (54) 8 (16) 18 (36) 24 (48) .69 Hydronephrosis, no. (%) Mild Moderate Severe 9 (18) 16 (32) 25 (50) 17 (34) 14 (28) 19 (38) .18 Left side stone, no. (%) 25 (50) 23 (46) 1389Vol. 11 | No. 02 | March- April 2014 |U R O LO G Y J O U R N A L patients‎ (94%)‎ in‎groups‎1‎and‎2,‎ respectively‎(P‎=‎ .18).‎ All‎seven‎patients‎in‎blind‎group‎with‎unsuccessful‎access‎ underwent‎fluoroscopy‎guided‎PCNL‎at‎the‎same‎operation‎ time.‎Also,‎the‎three‎patients‎with‎failed‎access‎in‎group‎2‎ successfully‎managed‎with‎fluoroscopic‎guided‎PCNL‎in‎an- other‎session‎of‎operation.‎The‎average‎number‎of‎percuta- neous‎punctures‎±‎SD‎needed‎to‎find‎the‎collecting‎system‎ was‎1.8‎±‎0.9/case‎in‎group‎1‎and‎1.5‎±‎0.7/case‎in‎group‎2‎ (P‎=‎.11).‎Both‎mean‎access‎time‎and‎mean‎operation‎time‎ were‎statically‎similar‎in‎group‎1‎and‎group‎2.‎Success‎rate‎ of‎procedure‎was‎80%‎in‎group1‎and‎88%‎in‎group‎2‎(P = .275).‎When‎moderate‎to‎severe‎hydronephrosis‎was‎present,‎ optimal‎exposure‎to‎ureteropelvic‎junction‎was‎possible‎even‎ from‎the‎lower‎pole‎by‎gently‎turning‎the‎nephroscope‎and‎ Amplatz‎sheath.‎ Intraoperative‎bleeding‎occurred‎in‎2‎patients‎(4%)‎in‎group‎ 1‎and‎one‎patient‎(2%)‎in‎group‎2,‎which‎were‎controlled‎by‎ tract‎dilation‎with‎balloon‎dilator.‎None‎of‎the‎patients‎ex- perienced‎post‎operative‎bleeding.‎Urinary‎collection‎devel- oped‎in‎one‎patient‎in‎group‎1,‎so‎the‎ureteral‎stent‎remained‎ for‎4‎days‎and‎the‎patient‎discharged‎without‎complication.‎ One‎(2%)‎patient‎in‎each‎group‎experienced‎sepsis‎which‎ were‎treated‎with‎broad‎spectrum‎antibiotics.‎Details‎of‎the‎ treatments‎in‎each‎group‎are‎summarized‎in‎Table‎2.‎Of‎pa- tients‎with‎failed‎PCNL,‎12‎patients‎underwent‎classic‎PCNL‎ and‎SWL‎performed‎in‎4‎patients. DISCUSSION Recently,‎PCNL‎considered‎as‎a‎safe‎and‎efficient‎modal- ity‎for‎management‎of‎various‎types‎of‎renal‎stone‎disease. (14)‎The‎first‎step‎in‎PCNL‎is‎access‎to‎the‎collecting‎system‎ which‎is‎usually‎achieved‎using‎fluoroscopy.(5)‎Insertion‎of‎ a‎nephrostomy‎tube‎under‎fluoroscopy‎accompanies‎with‎a‎ success‎rate‎of‎90-98%.(5,15) Blind Access Percutaneous Nephrolithotomy | Karami et al Table 2. Intraoperative and postoperative data of study subjects. Variables Blind Fluoroscopy-Guided P Access, no. (%) Direct Middle calyx Inferior calyx 2 (4) 37 (74) 11 (22) 0 41 (82) 9 (18) .30 Mean hemoglobin level (mg/dL) Before operation After operation Change 12.8 ± 1.3 11.8 ± 1.2 -0.96 ± 0.3 12.6 ± 1.1 11.9 ± 1.0 -0.82 ± 0.3 .40 .65 .20 Intraoperative bleeding, no. (%) 2 (4) 1 (2) NS Postoperative sepsis, no. (%) 1 (2) 1 (2) NS Postoperative bleeding, no. (%) 0.0 0.0 NS Injury to adjacent organs, no. (%) 0.0 0 NS Pyelocalyceal system disruption, no. (%) 1 (2) 0.0 NS Mean access time (minutes) 3.3 ± 0.5 3.6 ± 0.7 .15 Unsuccessful access, no. (%) 7 (14) 3 (6) .18 Mean operation time (minutes) 35.2 ± 4.6 38.9 ± 4.1 .10 Mean hospital staying (days) 2.7 ± 0.3 2.9 ± 0.3 .14 Success rate, no. (%) 40 (80) 44 (88) .275 Key: NS, not significant. 1390 | Many‎studies‎have‎investigated‎methods‎for‎lowering‎the‎dose‎ of‎X-ray‎used‎in‎PCNL,‎such‎as‎PCNL‎under‎ultrasonogra- phy guidance(15,16)‎and‎blind‎PCNL.(9-12).‎This‎is‎because‎of‎ adverse‎effects‎of‎radiation‎to‎human‎tissues.‎Previous‎stud- ies‎have‎been‎shown‎operating‎room‎personnel‎are‎within‎safe‎ radiation‎dose‎limits‎during‎PCNL.(8,17,18) In order to the del- eterious‎effects‎of‎radiation‎on‎tissue‎is‎not‎dose‎dependent,‎ surgical‎team‎should‎ALARA‎dose‎of‎radiation.(8) Chien‎and‎Bellman(9)‎performed‎blind‎access‎nephrostomy‎ in‎26‎patients‎with‎hydronephrosis‎without‎any‎significant‎ complication.‎In‎this‎study‎nephrostomies‎were‎performed‎ on‎hydronephrotic‎kidneys,‎but‎the‎degree‎of‎hydronephrosis‎ which‎could‎affect‎the‎success‎rate,‎had‎not‎been‎determined.‎ They‎reported‎98%‎success‎rate‎with‎the‎mean‎puncturing‎ attempts‎of‎2.5‎per‎patient.‎Direct‎access‎to‎the‎renal‎pelvis‎ was‎achieved‎in‎75%‎of‎the‎cases.‎ McDougall and colleagues(19) suggested blind access in cases with‎obstruction‎or‎stricture‎of‎the‎ureter,‎abnormal‎anatomy‎ of‎the‎ureteral‎orifice,‎or‎when‎the‎required‎equipment‎for‎the‎ standard‎approach‎is‎not‎available.‎In‎their‎experience,‎blind‎ access‎achieved‎by‎insertion‎of‎a‎22‎F‎Chiba‎needle‎with‎a‎ 90°‎angle,‎1‎cm‎to‎1.5‎cm‎lateral‎to‎lumbar‎1‎vertebra,‎for‎ antegrade‎procedures‎or‎contrast‎medium‎injection.‎ In‎our‎surgical‎team’s‎experience‎on‎treatment‎of‎impacted‎ upper‎ureteral‎calculi‎>‎1‎cm‎with‎blind‎access‎PCNL,‎both‎ success‎rate‎of‎achieving‎access‎and‎procedure‎were‎100%‎ without‎any‎major‎complication.(11)‎It‎means‎that‎in‎experi- enced‎hand,‎blind‎access‎PCNL‎could‎be‎performed‎with‎no‎ need‎to‎special‎instruments,‎and‎achieved‎a‎high‎success‎rate‎ in‎a‎short‎period‎with‎minimal‎morbidity‎especially‎in‎the‎ presence‎of‎moderate‎to‎severe‎hydronephrosis.‎In‎another‎ study(12)‎we‎used‎blind‎access‎for‎PCNL‎in‎128‎patients‎with‎ staghorn‎or‎pyelocaliceal‎stone‎with‎moderate‎to‎severe‎hy- dronephrosis‎which‎resulted‎in‎nearly‎success‎rate‎of‎90%.‎ Access‎was‎accomplished‎by‎touching‎the‎stones‎with‎the‎ needle,‎in‎cases‎with‎a‎large‎pelvis‎and‎staghorn‎stone. In‎a‎clinical‎trial‎study,‎Basiri‎and‎colleagues(10)‎compared‎ blind‎access‎with‎classic‎fluoroscopic‎PCNL.‎The‎success‎ rate‎of‎both‎achieving‎access‎and‎procedure‎in‎blind‎access‎ group‎were‎62%‎and‎100%,‎respectively;‎with‎no‎complica- tions‎of‎the‎initial‎access‎to‎the‎system.‎The‎number‎of‎punc- turing‎attempts‎was‎not‎different‎between‎the‎2‎groups. Mousavi-Bahar‎and‎colleagues(20)‎ reported‎success‎rate‎of‎ 87%‎in‎62‎cases‎of‎kidney‎calculus‎who‎underwent‎blind‎ac- cess‎PCNL. In‎this‎study,‎success‎rate‎was‎80%‎and‎88%‎and‎successful‎ access‎was‎86%‎and‎94%‎in‎blind‎and‎fluoroscopic‎PCNL,‎ respectively.‎All‎seven‎patients‎with‎failed‎access‎in‎blind‎ PCNL‎group‎underwent‎fluoroscopic‎one‎at‎the‎same‎operat- ing‎session‎with‎stone‎clearance‎of‎100%.‎Our‎stone‎free‎rate‎ was‎similar‎to‎Chien‎and‎Bellman’s‎study(9)‎but‎it‎was‎more‎ than‎Basiri‎and‎colleagues’‎report.(10)‎The‎access‎rate‎was‎ comparable‎in‎these‎studies.‎However,‎inability‎to‎design‎a‎ double‎blind‎clinical‎trial‎and‎low‎number‎of‎cases‎were‎the‎ major‎limitations‎of‎our‎study. CONCLUSION It‎seems‎that‎blind‎access‎is‎a‎safe‎and‎effective‎PCNL‎meth- od‎that‎could‎be‎performed‎by‎skilled‎endourologist,‎espe- cially‎for‎patient‎with‎large‎hydronephrotic‎kidney. CONFLICT OF INTEREST None declared. Endourology and Stone Disease REFERENCES 1. Fenstrom I, Johannson B. Percutaneous pyelolithoto- my: a new extraction technique. Scand J Urol Nephrol. 1976;10:257-9. 2. Kader AK, Finelli A, Honey RJ. Nephroureterostomy drained percutaneous nephrolithotomy: modification combining safety with decreased morbidity. J Endourol. 2004;18:29-32. 3. Montanari E, Serrago M, Esposito N, et al. Ultrasound fluor- oscopy guided access to the intrarenal excretory system. Ann Urol (Paris). 1999;33:168-81. 4. Delavierre D, Fournier G, Mangin P. Percutaneous drainage nephrostomy guided by ultrasound. Apropos of 80 adult cases. J Urol (Paris). 1989;95:319-29. 5. Patel U, Hussain FF. Percutaneous nephrostomy of nondi- lated renal collecting systems with fluoroscopic guidance: technique and results. Radiology. 2004;233:226-33. 6. Matlaga BR, Shah OD, Zagoria RJ, Dyer RB, Streem SB, Assi- mos DG. Computerized tomography guided access for per- cutaneous nephrostolithotomy. J Urol. 2003;170:45-7. 7. Karami H, Arbab AM, Rezaei A, Mohammadhoseini M, Rezaei I. Percutaneous nephrolithotomy with ultrasonogra- phy-guided renal access in the lateral decubitus flank posi- tion. J Endourol. 2009;23:33-5. 1391Vol. 11 | No. 02 | March- April 2014 |U R O LO G Y J O U R N A L 8. Kumari G, Kumar P, Wadhwa P, Aron M, Gupta NP, Dogra PN. Radiation exposure to the patient and operating room personnel during percutaneous nephrolithotomy. Int Urol Nephrol. 2006;38:207-10. 9. Chien GW, Bellman GC. Blind Percutaneous Renal Access. J Endourol. 2002;16:93-6. 10. Basiri A, Mehrabi S, Kianian H, Javaherforooshzadeh A, Kam- ranmanesh MR. Blind Puncture in Comparison With Fluoro- scopic Guidance in Percutaneous Nephrolithotomy A Rand- omized Controlled Trial. Urol J. 2007;4:79-83. 11. Karami H, Arbab AH, Hosseini SJ, Razzaghi MR, Simaei NR. Impacted upper-ureteral calculi >1 cm: blind access and totally tubeless percutaneous antegrade removal or retro- grade approach? J Endourol. 2006;20:616-9. 12. Karami H, Jabbari M, Arbab AH. Tubeless percutaneous nephrolithotomy: 5 years of experience in 201 patients. J Endourol. 2007;21:1411-3. 13. Bellman GC, Huang S, Tebyani N, et al. Lumbar notch: A technique in percutaneous renal access. Presented at the 16th World Congress on Endourology and SWL. New York, September 1998. 14. Consensus Conference. Prevention and treatment of kidney stones. JAMA. 1998;260:977-81. 15. Basiri A, Ziaee AM, Kianian HR, Mehrabi S, Karami H, Moghaddam SM. Ultrasonographic versus fluoroscopic ac- cess for percutaneous nephrolithotomy: a randomized clini- cal trial. J Endourol. 2008;22:281-4. 16. Gupta S, Gulati M, Uday Shankar K, Rungta U, Suri S. Percuta- neous nephrostomy with real-time sonographic guidance. Acta Radiol. 1997;38:454-7. 17. Rao PN, Faulkner K, Sweeney JK, Asbury DL, Sambrook P, Blacklock NJ. Radiation dose to patient and staff during per- cutaneous nephrostolithotomy. Br J Urol. 1987;59:508-12. 18. Inglis JA, Tolley DA, Law J. Radiation safety during percuta- neous nephrolithotomy. Br J Urol. 1989;63:591-3. 19. McDougall EM, Liatsikos EN, Dinlenc CZ, Smith AD. Percuta- neous approaches to the upper urinary tract. In: Walsh PC, Retik AB, Vaughan ED Jr, et al, editors. Campbell’s urology. 8th ed. Philadelphia: WB Saunders; 2002. p. 3320-45. 20. Mousavi-Bahar SH, Minaei MA. [Results of PCNL for renal and upper ureteral stones without fluoroscopy]. Sci J Hama- dan Univ Med Sci. 2003;10:35-8. Blind Access Percutaneous Nephrolithotomy | Karami et al PL Steinberg MD Department of Surgery, Dartmouth Hitchcock Medical Center , Lebanon, New Hampshire, USA. Comment on Blind versus Fluoroscopy- guided Percutaneous Neph- rolithotomy: A Randomized Clinical Trial I applaud‎ the‎ randomized‎ design,‎ but‎ the‎ au-thors‎should‎include‎a‎power‎analysis‎of‎why‎fifty‎patients‎per‎arm‎were‎used.‎What‎level‎of‎ difference‎did‎they‎want‎to‎detect‎and‎what‎is‎the‎ primary‎end‎point?‎Fluoroscopy‎access‎was‎more‎ successful,‎and‎the‎reason‎it‎may‎not‎be‎significant‎ is‎a‎small‎sample‎size.‎Stone-free‎rates‎are‎best‎as- sessed‎on‎post-operative‎computed‎tomography,‎not‎ kidney-ureter-bladder‎ X-ray.‎ The‎ stone‎ free‎ rates‎ may‎not‎be‎as‎good‎as‎suggested.‎Interpolar‎access‎ is‎usually‎only‎desirable‎for‎ureteropelvic‎junction‎ procedures‎and‎often‎is‎not‎a‎good‎angle‎for‎other‎ stone burdens. In addition these patients had a low body‎mass‎index‎and‎a‎small‎stone‎burden‎and‎I‎ wonder‎how‎well‎this‎would‎work‎with‎larger‎pa- tients and a larger stone burden.