Pole Calculi Research Articles

The Impact of Pelvicalyceal System Anatomy on Stone Formation in Patients with Single Lower Pole Calyceal Stone on Computed Tomography Urography.

To compare various lower pole pelvicalyceal anatomical factors of stone bearing kidney with contralateral normal kidneys and determine whether these factors predispose to stone formation in one kidney. A descriptive study was done with Computed Tomography of 54 patients with solitary lower pole calculus in one kidney and normal contralateral kidney were included. Various lower pole pelvicalyceal anatomical factors like infundibulopelvic angle, infundibular width, infundibular length and calyceopelvic height of both stone bearing and contralateral kidneys were measured and compared for any differences Results: The mean infundibular width was 5.4±1.9mm on stone bearing kidneys and 5.2±2.05mm on contralateral normal kidneys. The mean infundibular length was 18.9±4.4mm on stone bearing kidneys and 18.8±3.9mm on contralateral normal kidneys. The mean infundibulopelvic angle was 47.9±10.8° on stone bearing kidneys and 47.6±11.2° on contralateral kidneys. The mean calyceopelvic height was 15.7±4.6mm on stone bearing kidneys and 15.5±3.9mm (range 7.5to 23.1mm) on contralateral kidneys. There were no statistically significant differences between stone bearing and contralateral normal kidneys in respect to these pelvicalyceal anatomical factors. In this study, we found no significant difference in lower pole pelvicalyceal anatomical factors between stone bearing kidneys and contralateral normal kidneys and therefore these factors do not seem to have significant role in stone formation in one kidney compared with the other.

Осложнения ретроградной интраренальной хирургии у пациентов с камнями чашечек почки

A lot of patients with nephrolithiasis have calculi at low pole calyces. One of the best and safety operative options of such category is retrograde intrarenal surgery (RIRS). RIRS is wide spread in current clinical practice. But not rarely it corresponded with different grade complications. Current literature review is dedicated to predictors of complications due to RIRS in patients with low pole calculi.

Correlation between Anatomical Variations of Lower Pelvicalyceal System and Isolated Lower Pole Calculus Formation Compared with Non-stone Bearing Contralateral Kidney: Case Control Study

Introduction: Renal calculus is one of the common problems frequently encountered in clinical practice. Various factors play an important role in its formation.This study was done to find out the anatomical variations of the lower pole of the kidney bearing the calculus and compared it with the calculus-free contralateral kidney.
 Method: Patients with isolated lower pole calculus undergoing computed tomography urography and computed tomography of the abdomen and pelvis were included in the study. Infundibuloureteropelvic angle, infundibulocalyceal length, and infundibular width of the lower calyx of the stone-bearing kidney were measured and compared with the contralateral stone-free kidney.
 Result: A total of 37 patients were included for statistical analysis. The age of the patients ranged from 22 to 84 years with a mean age of 41.9±17.9 years. Infundibulocalyceal length (ICL) of the calculus-bearing kidney was significantly longer than the calculus-free kidney. Infundibuloureteropelvic angle (IUPA) of the calculus-bearing kidney was significantly more acute than a calculus-free kidney. There was no significant difference in infundibular width between the calculus bearing and calculus free kidney
 Conclusion: IUPA and ICL are significantly associated with lower pole calculus.

Super-mini percutaneous nephrolithotomy (SMP) vs retrograde intrarenal surgery (RIRS) in the management of renal calculi\u2009\u2264\u20092\xa0cm: a propensity matched study

ObjectiveTo compare the effectiveness and safety of Super-Mini PCNL (SMP) and Retrograde Intrarenal Surgery (RIRS) in the management of renal calculi ≤ 2 cm.Patients and methodsA prospective, inter-institutional, observational study of patients presenting with renal calculi ≤ 2 cm. Patients underwent either SMP (Group 1) or RIRS (Group 2) and were performed by 2 experienced high-volume surgeons.ResultsBetween September 2018 and April 2019, 593 patients underwent PCNL and 239 patients had RIRS in two tertiary centers. Among them, 149 patients were included for the final analysis after propensity-score matching out of which 75 patients underwent SMP in one center and 74 patients underwent RIRS in the other. The stone-free rate (SFR) was statistically significantly higher in Group 1 on POD-1 (98.66% vs. 89.19%; p = 0.015), and was still higher in Group 1 on POD-30 (98.66% vs. 93.24%, p = 0.092) SFR on both POD-1 and POD-30 for lower pole calculi was higher in Group 1 (100 vs. 82.61%, p = 0.047 and 100 vs 92.61% p = 0.171). The mean (SD) operative time was significantly shorter in Group 1 at 36.43 min (14.07) vs 51.15 (17.95) mins (p < 0.0001). The mean hemoglobin drop was significantly less in Group 1 (0.31 vs 0.53 gm%; p = 0.020). There were more Clavien–Dindo complications in Group 2 (p = 0.021). The mean VAS pain score was significantly less in Group 2 at 6 and 12 h postoperatively (2.52 vs 3.67, 1.85 vs 2.40, respectively: p < 0.0001), whereas the mean VAS pain score was significantly less in Group 1 at 24 h postoperatively (0.31 vs 1.01, p < 0.0001). The mean hospital stay was significantly shorter in Group 1 (28.37 vs 45.70 h; p < 0.0001).ConclusionSMP has significantly lower operative times, complication rates, shorter hospital stay, with higher stone-free rates compared to RIRS. SMP is associated with more early post-operative pain though.

Scope for management of big ureteric stones using classical Ayurveda medicines - A Single Case Study

Big Ureteric calculi presenting with acute renal colic have always been a condition to be managed by newer endoscopic techniques like Ureteroscopy (URS) and Shock Wave Lithotripsy (SWL). Though open surgeries have been replaced by these newer sophisticated techniques, yet their affordability and future complications are a matter of concern. Complications of anaesthesia and the procedure drive the patients to subsequent OPDs. In patients with normal kidney functioning, big ureteric calculi could be managed medically. This is the case of a 40- year- old lady diagnosed with a case of two calculi in right kidney - a lower pole tiny calculus (2.2mm) and a mid-ureteric calculus (13mm) in right side causing moderate hydroureteronephrosis with severe lower abdominal and flank pain. After conservative management with Tila-Dhatrikshara and Gokshurakashaya for 06 weeks, her symptoms vanished, lower pole calculus expelled out, ureteric calculus size reduced considerably by 4mm and the degree of hydroureteronephrosis reduced from moderate to mild.

Utilization of the Glue-clot Technique for Removal of Small Lower Pole Calculi in Pediatric Patients: Case Series

Glue-clot technique has been described as a method to remove small stone fragments in adults undergoing endourological management of renal calculi. In this case series, we share our experience of using this technique for retrieval of stone fragments in 4 children who underwent ureterorenoscopy. The fragments were mainly located in the lower calyces rendering stone extraction challenging. We were able to achieve complete clearance in all patients. This series represents the first use of glue-clot technique in pediatric ureterorenoscopy.

Robot-assisted partial nephrectomy and nephrolithotomy for multiple lower pole calculi in an atrophic kidney

Open renal stone surgery has been largely replaced by retrograde intrarenal surgery (RIRS), percutaneous nephrolithotomy (PCNL) and extracorporeal shockwave lithotripsy (ESWL). However, when these methods fail to remove a stone or there are certain contraindications, such as pregnancy and obesity, laparoscopic, robotic or open surgery may still be indicated. In fact, robotic surgery has been increasingly used by urologists for different benign indications including chronic pyelonephritis, neglected ureteropelvic junction obstruction and renal tuberculosis. This article describes a case of robotic-assisted partial nephrectomy and nephrolithotomy for a large amount of small lithiasis in a non-functioning lower pole after failed stone clearance with a single use Boston ureteroscope owing to non-accessibility.

A comparative study of minimally invasive percutaneous nephrolithotomy and retrograde intrarenal surgery for solitary renal stone of 1-2 cm.

Background:PCNL is the treatment of choice for renal stones. But wide array of complications due to larger tract size(>20 Fr) has lead to development of improved techniques like miniPCNL(<20 Fr) and RIRS(Retrograde intrarenal surgery).Aim and Objective:To perform a study comparing miniPCNL with RIRS for renal stones 1-2 cm with respect to stone free rate , complications and quality of life.Materials and Methods:A prospective, randomised study was carried out our tertiary care centre, recruiting 40 patients in each group from Dec 2016 to Oct 2018. Patients demographic characteristics, operative findings, surgical outcomes and quality of life( SF-36 questionnaire) were recorded with 3 months of follow-up.Results:RIRS has longer operative time (69.75 min > 51.58 min; p=0.003), lesser radiation exposure (p=0.012), shorter hospital stay (p =0.15), lesser blood loss and lesser post operative pain on POD1 and POD2 (p =0.005, p=0.001 respectively). RIRS group patients sufferred more post op complications (p=0.03 )of which urosepsis was most common. Stone free rate is significantly better(p =0.003) in miniPCNL group on POD1 , while SFR's at 1 month (miniPCNL-90% and RIRS -85%) and 3 month (miniPCNL- 92.5% and RIRS -87.5%) was better in miniPCNL group, but statistically insignificant.On subgroup analysis SFR in lower pole calculus was better in miniPCNL group at 1month and 3 month (p=0.008). Second intervention for stone clearance was required in 3 patients of miniPCNL and 5 patients of RIRS, out of which 4 had lower pole stone.No significant differnce was found in quality of life in both groups at 1 month.Conclusion:MiniPCNL is a better treatment modality for higher single step stone free rate, shorter operative time and fewer postop complication. RIRS has SFR slightly less than miniPCNL but has less radiation exposure and much less post operative pain. There is no significant difference in quality of life in both groups.

Ретроградная гибкая уретероскопия с тулиевой волоконной нефролитотрипсией в лечении пациентов с камнем нижней полярной чашечки

Introduction The SuperPulse Thulium (Tm) fiber laser (wavelength of 1.94 m) has been recently introduced as a directed-energy source for urology. Preclinical studies have shown a significant potential of the SuperPulse Tm fiber laser (SP TFL) for lithotripsy. However, clinical reports of using SP TFL to treat urolithiasis are still few and limited. Of special interest are challenging cases, e.g., lower pole stones, when extreme deflection of the instrument is required. Objective To evaluate the effectiveness of the SuperPulse Tm fiber laser in the management of lower pole small calyceal stones during flexible ureteroscopy (F-URS). Method s. The SuperPulse Tm fiber laser device (Urolase 2, IRE Polus, Fryazino, Russia) has been cleared for clinical use by the Ministry of Health of Russian Federation. Study protocol has been approved by the Ethical Review Committee. Between January 2018 and February 2019, 130 patients with kidney stones have undergone Thulium fiber laser lithotripsy during F-URS. We retrospectively analyzed 15 of this patients with a single radiopaque lower pole calculus that were included in the present study. Stone size, stone density, lithotripsy time (from the first to last footswitch press) and lasering (laser emission) time were measured. The SP TFL was used for stone disintegration with different settings in dusting and fragmentation modes (0.1 - 4J, 7-300Hz, 6-40W) via a fiber with a 200-m core diameter. Low dose CT scanning was performed on POD 90 to assess SFR. Results Stone size ranged from 4 to 17 mm and stone density varied from 350 to 1459 HU. The average lithotripsy time was 12 min (3-30 min). The average lasering time was 1.3 min (0.4-2.5 min) and the mean hospital stay was 1.1+/-0.3 days. In all cases we reached the lower pole stone containing calyx with a laser fiber. The complication rates were evaluated by using the Clavien-Dindo grading system and did not exceed GII (6.6%). SFR on POD 90 was achieved in 86.6% of cases. Conclusions F-URS with SuperPulse Tm fiber laser is safe and effective option in the management of lower pole small calyceal stones. The possibility of using small laser fibers gives better instrument deflection which make possible to reach lower pole calyceal stones even with acute lower pole infundibulopelvic angle (IPA).

PD34-06 FLEXIBLE URETEROSCOPY FOR LOWER POLE RENAL STONES: NOVEL SUPERPULSE THULIUM (TM) FIBER LASER LITHOTRIPSY. FIRST CLINICAL RESULTS

You have accessJournal of UrologyStone Disease: Surgical Therapy V (PD34)1 Apr 2020PD34-06 FLEXIBLE URETEROSCOPY FOR LOWER POLE RENAL STONES: NOVEL SUPERPULSE THULIUM (TM) FIBER LASER LITHOTRIPSY. FIRST CLINICAL RESULTS Dmitry Korolev*, Roman Klimov, Dmitry Tsarichenko, Mikhail Enikeev, Alim Dymov, Stanislav Ali, Gagik Akopyan, Vladimir Lekarev, Mark Taratkin, Leonid Rapoport, Dmitry Enikeev, and Peter Glybochko Dmitry Korolev*Dmitry Korolev* More articles by this author , Roman KlimovRoman Klimov More articles by this author , Dmitry TsarichenkoDmitry Tsarichenko More articles by this author , Mikhail EnikeevMikhail Enikeev More articles by this author , Alim DymovAlim Dymov More articles by this author , Stanislav AliStanislav Ali More articles by this author , Gagik AkopyanGagik Akopyan More articles by this author , Vladimir LekarevVladimir Lekarev More articles by this author , Mark TaratkinMark Taratkin More articles by this author , Leonid RapoportLeonid Rapoport More articles by this author , Dmitry EnikeevDmitry Enikeev More articles by this author , and Peter GlybochkoPeter Glybochko More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000905.06AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The SuperPulse Thulium (Tm) fiber laser (wavelength of 1.94 µm) has been recently introduced as a directed-energy source for urology. Preclinical studies have shown a significant potential of the SuperPulse Tm fiber laser (SP TFL) for lithotripsy. However, clinical reports of using SP TFL to treat urolithiasis are still few and limited. Of special interest are challenging cases, e.g., lower pole stones, when extreme deflection of the instrument is required. To evaluate the effectiveness of the SuperPulse Tm fiber laser in the management of lower pole small calyceal stones during flexible ureteroscopy (F-URS). METHODS: The SuperPulse Tm fiber laser device (Urolase 2, IRE Polus, Fryazino, Russia) has been cleared for clinical use by the Ministry of Health of Russian Federation. Study protocol has been approved by the Ethical Review Committee. Between January2018 and February 2019, 130 patients with kidney stones have undergone Thulium fiber laser lithotripsy during F-URS. We retrospectively analyzed 15 of this patients with a single radiopaque lower pole calculus that were included in the present study. Stone size, stone density, lithotripsy time (from the first to last footswitch press) and “lasering” (laser emission) time were measured. The SP TFL was used for stone disintegration with different settings in dusting and fragmentation modes (0.1 – 4J, 7-300Hz, 6-40W) via a fiber with a 200-μm core diameter. Low dose CT scanning was performed on POD 90 to assess SFR. RESULTS: Stone size ranged from 4 to 17 mm and stone density varied from 350 to 1459 HU. The average lithotripsy timewas 12 min (3-30 min). The average “lasering” time was 1.3 min (0.4-2.5 min) and the mean hospital stay was 1.1 ± 0.3 days. In all cases we reached the lower pole stone containing calyx with a laser fiber. The complication rates were evaluated by using the Clavien-Dindo grading system and did not exceed GII. The overall postoperative complication rate was 26.6% (GI 20%; GII 6.6%). SFR on POD 90 was achieved in 86.6% of cases. CONCLUSIONS: F-URS with SuperPulse Tm fiber laser is safe and effective option in the management of lower pole small calyceal stones. The possibility of using small laser fibers gives better instrument deflection which make possible to reach lower pole calyceal stones even with acute lower pole infundibulopelvic angle (IPA). Source of Funding: non © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e713-e713 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Dmitry Korolev* More articles by this author Roman Klimov More articles by this author Dmitry Tsarichenko More articles by this author Mikhail Enikeev More articles by this author Alim Dymov More articles by this author Stanislav Ali More articles by this author Gagik Akopyan More articles by this author Vladimir Lekarev More articles by this author Mark Taratkin More articles by this author Leonid Rapoport More articles by this author Dmitry Enikeev More articles by this author Peter Glybochko More articles by this author Expand All Advertisement PDF downloadLoading ...

Factors Affecting Safety and Efficacy of PCNL in Lower Calyceal Stones

AbstractBackground: The management of lower calyceal stones is still one of today's topics in endourology. Percutaneous nephrolithotomy (PCNL) is found to be a highly effective procedure in treatment of lower pole calculi. However, many factors are affecting the stone free rate and complication rate.Aim of the Study: The aim of this study was to evaluate the factors that affect the safety and efficacy of PCNL in lower calyceal stones more than 2cm.Patients and Methods: Forty eight patients with lower pole calculi more than 2 cm underwent percutaneous nephro-lithotomy. Preoperative, operative and postoperative data were reported. Multivariate analyses as well as univariate analyses were used to investigate the effects of different variables on residual stones and blood transfusion rate. These factors include age, sex, laterality, body mass index, history of ipsilateral open renal surgery, operative time, lower pole parenchymal thickness, presence of hydronephrosis, stone burden and stone density.Results: Unvariate analysis determined that stone burden (p<0.001), stone count (p<0.02), lower pole parenchymal thickness (p<0.03), presence of hydronephrosis (p<0.001) and operative time (p<0.04) were statistically significant with the stone free rate. Multivariate analysis revealed that, presence of hydronephrosis (odds ratio [OR]: 0.365, 95% confidence interval [CI]: 0.104-0.652, p=0.034), lower pole parenchymal thickness (OR: 0.347, 95% CI: 0.241-0.874, p=0.04), the operative time (OR: 0.587, 95% CI: 0.149-0.857, p=0.032), stone count (OR: 0.647, 95% CI: 0.205-0.874, p=0.028) and stone burden (OR: 0.428, 95% CI: 0.169-0.985, p=0.021) were significant independent factors influence stone residual. Univariate analysis determined that stone burden (p<0.001), body mass index (p<0.015), history of ipsilateral open renal surgery (p<0.017), lower pole parenchymal thickness (p<0.001) and operative time (p<0.015) correlated with blood transfusion rate. Multivariate analysis revealed that stone burden (OR: 0.628, 95% CI: 0.149-0.852, p=0.014), operative time (OR: 0.452, 95% CI: 0.125-0.856, p=0.002), lower pole parenchymal thickness (OR: 0.365, 95% CI: 0.014-0.836, p=0.002), body mass index (OR: 0.589, 95% CI: 0.159-0.744, p=0.038) and history of ipsilateral surgery (OR: 0.635, 95% CI: 0.258- 0.825, p=0.017) were significant independent factors influence blood transfusion rate. Conclusion: PCNL is a safe and effective procedure for lower calyceal stones more than 2cm. The stone free rate in the study was affected mainly by the stone burden and the operative time, the stone count, the degree of hydronephrosis and the lower pole parenchymal thickness were also involved. The blood transfusion rate was also affected by the stone burden, the operative time, the BMI, history of ipsilateral open renal surgery and the lower pole parenchymal thickness.

The treatment of renal lower pole calculi with flexible ureteroscope and percutaneous nephrolithotomy in obese patients

Objective To evaluate the efficacy and safety of flexible ureteroscopy (FURS) for the treatment of renal lower pole calculi in obese patients. Methods From October 2012 to May 2017, a total number of 184 obese patients(body mass index, BMI≥30) with lower pole kidney stones were randomly divided into two groups, FURS group(n=65) and percutaneous nephrolithotomy(PNL) group (n=119). The mean stone size was (15.8±5.7)mm in FURS group and (18.6±4.9)mm in PNL group. Results All of the D-J stents were removed 4 weeks after operation in both groups, and ultrasonic or X-Ray 87.69% vs. 89.92% (P>0.05). Residual stones were found in 8 vs. 12 patients in each group, and all disappeared after active lithagogue treatment with external physical vibration lithecbole (EPVL). Complications in FURS group were lower than PNL group , including fever(1 vs. 2), pain(8 vs. 23), perirenal hematoma(none vs. 1) , the visual analogue scale/score(3.3±1.1) vs.(5.6±0.9) and hospital stay(3.7±0.6) d vs. (5.4±0.8 ) d was also lower(P<0.05). Conclusions FURS is a safe and efficient option for renal lower pole calculi in obese patients. Key words: Kidney Calculi; Nephrostomy, Percutaneous; Ureteroscopes; Obesity

Miniperc vs Shockwave Lithotripsy for Average-Sized, Radiopaque Lower Pole Calculi: A Prospective Randomized Study.

Introduction: To detect safety and feasibility of miniperc and extracorporeal shockwave lithotripsy (SWL) for treatment of average-sized (1-2 cm), radiopaque lower pole calculi in a prospective randomized manner. Patients and Methods: In the period from January 2014 to June 2015, 150 patients were attached to this study with single lower pole radiopaque stone ranging from 10 to 20 mm. Patients were divided randomly into two groups using computer-generated randomization in an equal manner. First group patients were subjected to miniperc procedure, while second group patients underwent SWL. Patient's characters, stones' characters, fluoroscopic time, operative time, blood transfusion, hospital stay, retreatment, auxiliary procedure (AP), and complications using modified Clavien grading are tabulated and analyzed. Results: This study included two equal groups with 75 patients in each group. With regard to age (37.75 ± 11.25 vs 40.55 ± 10.55), body mass index (26.92 ± 2.26 vs 27.29 ± 2.87), and stone size (1.55 ± 0.28 vs 1.57 ± 0.26), there was no significant statistical difference in both groups. Stone-free rate (SFR) (76% vs 96%), operative time (44.81 ± 7.06 vs 93.37 ± 12.29 minutes), fluoroscopy time (53 ± 2.45 vs 180 ± 7.31 seconds), hospital stay (5.72 ± 1.01 vs 45.19 ± 8.48 hour), and blood transfusion were significantly more in the miniperc group. Retreatment rate (45.3% vs 2.7%) and AP (24% vs 4%) were significantly greater in the SWL group. Conclusion: SWL is less invasive than percutaneous stone removal, but it is also less effective for lower pole radiopaque calculi. Miniperc has better SFR and lower auxiliary and retreatment rates; however, it resulted in more drawbacks.

Contemporary Practice Patterns of Flexible Ureteroscopy for Treating Renal Stones: Results of a Worldwide Survey.

Flexible ureteroscopy (fURS) is increasingly used in the treatment of renal stones. However, wide variations exist in technique, use, and indications. To better inform our knowledge about the contemporary state of fURS for treating renal stones, we conducted a survey of endourologists worldwide. An anonymous online questionnaire assessing fURS treatment of renal stones, consisting of 36 items, was sent to members of the Endourology Society in October 2014. Responses were collected through the SurveyMonkey system over a 3-month period. Questionnaires were answered by 414 surgeons from 44 countries (response rate 20.7%). U.S. surgeons accounted for 34.4% of all respondents. fURS was routinely performed in 80.0% of institutions, with 40.0% of surgeons performing >100 cases/year. Respondents considered fURS to be first-line therapy for patients with renal stones <2 cm and lower pole calculi. A substantial minority (11.3%) preferred fURS as a primary treatment modality for renal stones >2 cm. Basket displacement for lower pole stones was routinely performed by 55.8%. Ureteral access sheaths (UAS) were preferred for every case by 58.3%. Respondents frequently utilized high-power lasers and dusting techniques. Criteria for determining stone-free rate were defined as zero fragments or residual fragment (RF) <1, <2, <3, and <4 mm by 30.9%, 8.9%, 31.5%, 15.8%, and 11.2% of respondents, respectively. The overwhelming majority of endourologists surveyed consider fURS as a first-line treatment modality for renal stones, especially those <2 cm. Use of UAS, high-power holmium lasers, and dusting technique has become popular among practitioners. When defining stone free after fURS, the majority of endourologists used a zero fragment or RF <2 mm definition.

Impact of Renal Anatomy on Shock Wave Lithotripsy Outcomes for Lower Pole Kidney Stones: Results of a Prospective Multifactorial Analysis Controlled by Computerized Tomography

We evaluated which variables impact fragmentation and clearance of lower pole calculi after shock wave lithotripsy. We prospectively evaluated patients undergoing shock wave lithotripsy for a solitary 5 to 20 mm lower pole kidney stone between June 2012 and August 2014. Patient body mass index and abdominal waist circumference were recorded. One radiologist blinded to shock wave lithotripsy outcomes measured stone size, area and density, stone-to-skin distance, infundibular length, width and height, and infundibulopelvic angle based on baseline noncontrast computerized tomography. Fragmentation, success (defined as residual fragments less than 4 mm in asymptomatic patients) and the stone-free rate were evaluated by noncontrast computerized tomography 12 weeks postoperatively. Univariate and multivariate analysis was performed. A total of 100 patients were enrolled in the study. Mean stone size was 9.1 mm. Overall fragmentation, success and stone-free rates were 76%, 54% and 37%, respectively. On logistic regression body mass index (OR 1.27, 95% CI 1.11-1.49, p = 0.004) and stone density (OR 1.0026, 95% CI 1.0008-1.0046, p = 0.005) significantly impacted fragmentation. Stone size (OR 1.24, 95% CI 1.07-1.48, p = 0.039) and stone density (OR 1.0021, 95% CI 1.0007-1.0037, p = 0.012) impacted the success rate while stone size (OR 1.24, 95% CI 1.04-1.50, p = 0.029), stone density (OR 1.0015, 95% CI 1.0001-1.0032, p = 0.046) and infundibular length (OR 1.1035, 95% CI 1.015-1.217, p = 0.015) impacted the stone-free rate. The best outcomes were found in patients with a body mass index of 30 kg/m(2) or less, stones 10 mm or less and 900 HU or less, and an infundibular length of 25 mm or less. The coexistence of significant unfavorable variables led to a stone-free rate of less than 20%. Obese patients with higher than 10 mm density stones (greater than 900 HU) in the lower pole of the kidney with an infundibular length of greater than 25 mm should be discouraged from undergoing shock wave lithotripsy.

Efficacy of flexible ureteroscopy and laser lithotripsy for lower pole renal calculi

Objective: Our aim was to determine whether flexible ureterorenoscopy and laser lithotripsy is efficacious and safe in treating lower pole renal calculi. Materials and methods: Patient, procedure and stone data of patients who underwent flexible ureterorenoscopy and laser lithotripsy at our referral centre were collected prospectively between November 2005 and November 2011 and entered into a designated database. In all, 242 procedures were performed in 198 patients. Results: The mean age was 51.2 years. The mean calculi size was 10.51 mm (range 4–27 mm). Thirty seven patients had more than one stone in the lower pole. An access sheath was used in 19 patients (9.6%), 171 (86.4%) had a ureteric stent inserted after the procedure, and 165 patients had a single procedure. Re-operation rate was 16.7%. Stone-free rates after one procedure were 89%, 80% and 41%, respectively, for calculi measuring 4–10 mm ( n=107), 11–20 mm ( n=76) and &gt; 20 mm ( n=15). The overall stone-free rate was 83%, 91% and 95% after one, two and three procedures, respectively. Conclusion: Flexible ureterorenoscopy and laser lithotripsy is a safe and effective minimally invasive treatment option for patients with 4–20 mm lower pole calculi. Staged procedures, however, become necessary as the size of the stone increases greater than 20 mm, and this should be mentioned when counselling patients for their primary procedure.

Managing caliceal stones

The natural course of untreated asymptomatic caliceal calculi has not been clearly defined, especially in terms of disease progression, and the indications for and outcomes of surgical intervention are not precise. Caliceal stones may remain asymptomatic but, in case of migration, ureteral calculi can cause acute ureteric colic with severe complications. The decision for an active treatment of caliceal calculi is based on stone composition, stone size and symptoms. Extracorporal shock-wave lithotripsy (ESWL) has a low complication rate and is recommended by the current guidelines of the European Association of Urology as a first-line therapy for the treatment of caliceal stones <2 cm in diameter. However, immediate stone removal is not achieved with ESWL. The primary stone-free rates (SFR) after ESWL depend on stone site and composition and, especially for lower pole calculi, the SFR differ widely from other caliceal stones. Minimally-invasive procedures including percutaneous nephrolithotomy and ureteroscopy are alternatives for the treatment of caliceal stones, associated with low morbidity and high primary SFR when performed in centers of excellence.

Nephrolithiasis in “Back-to-back” Kidneys

A 57-year-old woman presented with a 1-week history of left lower quadrant pain and nausea and vomiting. Computed tomography without contrast demonstrated a left 2.3-cm calculus at the ureteropelvic junction and a 6-mm lower pole calculus. The kidneys were in the pelvis and oriented "back-to-back," with the lateral portions of the kidneys fused in the midline. To our knowledge, this is the first description of this renal fusion anomaly. The patient underwent robotic pyelolithotomy of the ureteropelvic junction calculus and subsequent flexible ureteroscopic laser lithotripsy of the lower pole calculus and ureteral stent placement through the assistant working port.

Impact of Lower Pole Calculi in Patients Undergoing Retrograde Intrarenal Surgery

To assess if the presence of a lower pole stone (LPS) decreases the stone-free (SF) rate following retrograde intrarenal surgery (RIRS). The second purpose was to assess the result of RIRS for LPS and to identify predictors of SF status. We retrospectively analyzed 205 procedures in 162 patients with renal stones treated by RIRS between January 2010 and January 2013 at a single institute. The SF status was defined as no residual fragments. Independent-sample t-tests and Chi-square tests were used for comparisons of means and proportions, respectively, between patients with or without LPS. Logistic regression models were used to assess prognostic factors influencing SF status in cases of LPS. LPS were present in 89 (54.9%) patients. There were no differences between patients with or without LPS regarding the mean operative time (p=0.77), the surgeon's experience (p=0.522), the length of hospital stay (p=0.269), and the SF rate (p=0.224). SF status after RIRS in patients with or without LPS was 74.1% and 78% (p=0.224), respectively. In the case of LPS, the presence of multiple stones and a history of percutaneous nephrolithotomy (PCNL) were predictive factors for occurrence of residual fragments in univariate analysis (p=0.037 and p=0.015). In multivariable analysis, only the presence of multiple stones remained as a predictive factor (p=0.027; HR=3.2), whereas a trend was observed when there was a history of PCNL (p=0.07; HR=3). The presence of a LPS does not alter the SF rate of RIRS even in cases of early experience. RIRS for LPS appears to be an effective technique, but special attention should be given to patients with multiple stones and/or a history of PCNL.

Comparison of Tissue Injury from Focused Ultrasonic Propulsion of Kidney Stones Versus Extracorporeal Shock Wave Lithotripsy

Focused ultrasonic propulsion is a new noninvasive technique designed to move kidney stones and stone fragments out of the urinary collecting system. However, to our knowledge the extent of tissue injury associated with this technique is not known. We quantitated the amount of tissue injury produced by focused ultrasonic propulsion under simulated clinical treatment conditions and under conditions of higher power or continuous duty cycles. We compared those results to extracorporeal shock wave lithotripsy injury. A human calcium oxalate monohydrate stone and/or nickel beads were implanted by ureteroscopy in 3 kidneys of live pigs weighing 45 to 55 kg and repositioned using focused ultrasonic propulsion. Additional pig kidneys were exposed to extracorporeal shock wave lithotripsy level pulse intensity or continuous ultrasound exposure 10 minutes in duration using an ultrasound probe transcutaneously or on the kidney. These kidneys were compared to 6 treated with an unmodified Dornier HM3 lithotripter (Dornier Medical Systems, Kennesaw, Georgia) using 2,400 shocks at 120 shock waves per minute and 24 kV. Histological analysis was performed to assess the volume of hemorrhagic tissue injury created by each technique according to the percent of functional renal volume. Extracorporeal shock wave lithotripsy produced a mean ± SEM lesion of 1.56% ± 0.45% of functional renal volume. Ultrasonic propulsion produced no detectable lesion with simulated clinical treatment. A lesion of 0.46% ± 0.37% or 1.15% ± 0.49% of functional renal volume was produced when excessive treatment parameters were used with the ultrasound probe placed on the kidney. Focused ultrasonic propulsion produced no detectable morphological injury to the renal parenchyma when using clinical treatment parameters but produced injury comparable in size to that of extracorporeal shock wave lithotripsy when using excessive treatment parameters.