The endourological management of complications associated with horseshoe kidney. J Urol. 2002;168:5-8. [PMID: 12050480 DOI: 10.1016/s0022-5347(05)64819-7]

Laparoscopic strategies in complex upper urinary tract obstruction

OBJECTIVES

We enumerate the various laparoscopic strategies to resolve upper urinary tract (UUT) obstruction in the context of variations in anatomy and report their outcomes.

PATIENTS AND METHODS

Retrospective review of primary laparoscopic UUT reconstructions performed between May 2012 and May 2021. Anomalies included: malrotated kidney (MRK), horseshoe kidney (HSK), duplex kidney (DK), pure intrarenal pelvis (IRP) and mid-ureteric stenosis (MUS). Success was defined by postoperative resolution of symptoms, improvement of anterior-posterior renal pelvic diameter (APD) on US and drainage on Mag3. Complications were categorised by Clavien-Dindo grading. Outcomes compared using the student's t-test with P < 0.05 considered statistically significant.

RESULTS

Of the 214 laparoscopic primary UUT reconstructions, 37 (17.2 %) were: 13-MRK, 12-HSK, 4-DK, 4-IRP and 4-MUS. Median age at surgery was 5-years (range 0.3-15). Dismembered pyeloplasty: 8; pyeloplasty with renal sinus dissection: 8; neo-PUJ anastomosis: 8; primary ureterocalycostomy: 7; pyeloureterostomy: 2; and uretero-ureterostomy: 4. Median follow-up was 43-months (range 8-108) with a success rate of 94.5 % (35/37). Complete resolution of symptoms in 20/21 patients; improvement of hydronephrosis on US in 35/37 patients (median pre-operative APD 27 mm vs. median postoperative APD 8 mm) [P < 0.001]; improvement of drainage on diuretic renogram in 32/34 kidneys and stable/improved DRF in 34/35 kidneys (median preoperative DRF - 45 % vs. median postoperative DRF - 47 %) [P > 0.05]. Postoperative complications managed medically (II Clavien) included urinary tract infections - 2 patients (5 %), stent-related symptoms in 2 (5 %) and umbilical port site collection in 1 patient (3 %). Recurrent pelvi-ureteric junction obstruction PUJO occurred in one patient (3 %) requiring redo surgery (IIIb Clavien), renal stones in 1 (3 %) which resolved with ESWL (IIIb Clavien); in 1 (3 %) patient with a HSK there was complete loss of ipsilateral kidney function but this was managed conservatively up to date (I Clavien).

CONCLUSION

Laparoscopic transperitoneal approach allows the prompt recognition of in-situ anatomical variants. UUT obstruction in such settings calls for a variety of strategies with excellent outcomes.

Comparative evaluation of urolithiasis management options in patients with horseshoe kidney: A systematic review and meta-analysis

Background

Horseshoe kidney is a rare congenital anomaly commonly complicated by urolithiasis. Extracorporeal shockwave lithotripsy (ESWL), ureteroscopy (URS), and percutaneous nephrolithotomy (PCNL) are treatment options for horseshoe kidney stones. The aim of this systematic review is to compare the benefits and risks of these management options.

Methods

MEDLINE, EMBASE, and Cochrane Library databases were searched from inception to February 2022. A total of 516 nonduplicate studies were screened against the inclusion and exclusion criteria. Studies comparing at least 2 interventions with ≥10 patients per intervention were included.

Results

Nine retrospective observational studies published from 2007 to 2021 with a total of 565 patients were included. Reported mean ± SD or mean (range) stone sizes ranged between 17.90 ± 2.43 mm and 27.9 ± 8.6 mm for PCNL, 8.4 (2-25) mm and 22.3 ± 9.1 mm for URS, and 11.9 ± 2.0 mm and 16.8 ± 4.4 mm for ESWL. There was no difference in single-session and overall stone-free rate (SFR) between PCNL and URS, with a risk ratio of 1.04 (95% confidence interval, 0.95-1.13; I2 = 20.63%). Ureteroscopy had better stone clearance than ESWL, with an overall SFR risk ratio of 1.38 (95% confidence interval, 1.04-1.82; I2 = 0%). There was no statistically significant difference in overall SFR between PCNL and ESWL. Most patients who underwent URS and ESWL experienced Clavien-Dindo (CD) grade I-II complications. Percutaneous nephrolithotomy was associated with the highest complication rates, including 5 CD grade III and 3 CD grade IV complications and a mean postoperative hemoglobin drop of 0.47 to 1.83 g/dL. There were no CD grade V complications across all studies.

Conclusions

There was no difference in SFR between PCNL and URS. Ureteroscopy was associated with a smaller stone burden and fewer and less severe complications. Ureteroscopy was found to be more effective than ESWL with a higher SFR and comparable safety profile. Further large-scale randomized controlled trials are needed to confirm these findings.

Implications of Tumor Surgery in Horseshoe Kidneys: A Comparative Study of Outcomes and Surgical Practices

OBJECTIVE

To contrast surgical outcomes of Horseshoe Kidney (HSK) patients with localized renal masses suspected of cancer with nonfused nonectopic kidney patients, emphasizing safe surgical practices for HSKs.

METHODS

The study examined solid tumors from the Mayo Clinic Nephrectomy registry between 1971 and 2021. Each HSK case was matched to three non-HSK patients based on various factors. The outcomes measured included complications within 30days of surgery, change in estimated glomerular filtration rate, and overall, cancer-specific, and metastasis-free survival rates.

RESULTS

Thirty of the 34 HSKs had malignant tumors compared with 90 of the 102 patients in the nonfused nonectopic referent cohort. Accessory isthmus arteries were present in 93% of HSK cases, with 43% exhibiting multiple arteries and 7% with 6 or more arteries. Estimated blood loss and surgery duration were significantly higher in HSKs (900 vs 300 mL, P = .004; 246 vs 163 minutes, P < .001, respectively). The HSK group demonstrated an overall complication rate of 26% (vs 17% in referents, P = .2) and a median change in estimated glomerular filtration rate at 3months of - 8.5 (vs -8.1 in referents, P = .8). At 5-year follow-up, survival rates for HSK patients were 72%, 91%, and 69% for overall, cancer-specific, and metastasis-free survival, respectively. The corresponding rates were 79%, 86%, and 77%, respectively, for matched referent patients (P > .05).

CONCLUSION

HSK tumor management is technically challenging with higher blood loss; however, the data demonstrate comparable outcomes for patients with HSK tumors, including complications and survival, to those without HSKs in experienced centers.

Optimal patient position for percutaneous nephrolithotomy in horseshoe kidneys: Traditional prone or supine?

OBJECTIVE

Although it was stated that supine percutaneous nephrolithotomy (PCNL) was associated with relatively shorter surgical times and comparable success and complication rates, there is no consensus in the current literature concerning the safety and efficacy of supine PCNL in patients with horseshoe kidneys. We aimed to compare supine and prone PCNL regarding safety and efficacy in patients with horseshoe kidneys.

METHODS

Data of the patients with horseshoe kidneys who underwent PCNL for renal stones larger than 2 cm between January 2010 and May 2021 were retrospectively reviewed. The study patients were categorized as Group 1 (i.e., supine PCNL-SPCNL) and Group 2 (i.e., prone PCNL-PPCNL). Both groups were compared regarding demographic, clinical, and surgical data.

RESULTS

Sixty-five patients were included. Among these patients, 31 (47.7%) were in Group 1, while 34 (52.3%) were in Group 2. Both groups were statistically similar in terms of demographic data, stone characteristics, perioperative parameters, and complication rates (p > 0.05). There was no statistical difference in terms of additional treatment rates, stone-free rates in the postoperative second-day and third-month evaluations (p > 0.05). Mean surgical time was significantly longer in Group 2 (113 ± 17.1 min) than in Group 1 (90.6 ± 11.3 min) (p = 0.000).

CONCLUSION

Although it is traditionally performed in the prone position, the supine approach is as safe and effective as the prone approach. In addition, the supine approach is associated with significantly shorter surgical times.

Percutaneous nephrolithotomy in horseshoe kidney: comparing ultrasound-guided access in flank position with conventional fluoroscopic-guided in prone position

We conducted this study to compare radiation-free US-guided percutaneous nephrolithotomy (PNL) in the flank position with conventional PNL in the prone position for the treatment of renal stones in patients with horseshoe kidneys. In a retrospective study, 14 HSK patients that were treated with conventional fluoroscopy-guided PNL in the prone position (group A) were compared with twenty-four HSK patients that were treated US-guided PNL in the flank position (group B). Data on baseline characteristics, percentage of successful entries, stone-free rate, duration of admission and complication rate were obtained from data registry. The average duration of the operation was 57.6 min in group B, which was statistically less than group A with 65.9 min (P = 0.001). Access time varied from 10 to 32.4 min (mean = 17.1 min) in group A and 5-29.5 min (mean = 10.9 min) in group B (P < 0.001). Access length had a significant relation to the surgery method so PNL with US-guided had less access length (P = 0.002). There was no significant relationship between the surgery guide and the residual stone rate (P = 0.6). Hemoglobin decrease (P = 0.5), hospitalization duration (P = 0.5) and need for blood transfusion (P value = 0.6) were not statistically different between the two groups. PNL with US guidance in flank position is a safe and effective technique in HSK patients and is associated with fewer complications than the traditional approach as well as reduced operating time, radiation exposure, and its complications.

Horseshoe Kidney With a Documented Giant Calculi: A Case Report

The horseshoe kidney is the most frequent genitourinary fusion abnormality. The horseshoe kidney is a combination of the anatomical abnormalities of ectopia and malrotation. Along with other anomalies, it is linked to malrotations, fluctuating blood flow, high ureter insertion, a tendency to establish a ureteropelvic junction, and blockage in up to one-third of patients, and these are all symptoms of this condition. Kidney calculus and pelvic ureteric junction (PUJ) obstruction are one of horseshoe kidneys' most prevalent side effects and are seen in approximately one-third of the patients. In our case report, we discuss the treatment of a 61-year-old male patient who had been complaining of abdominal pain for the past few years, was found to have a horseshoe kidney, a history of recurrent renal calculi with a non-functioning right side portion, and recurrent urinary tract infections (UTI) treated with open surgery. The patient symptomatically alleviated his symptoms at the three-month follow-up after open surgery; there were no complaints of discomfort or abdominal fullness, and the patient resumed daily routines.

Lower pole anatomy of horseshoe kidney and complete ureteral duplication: Anatomic and radiologic study applied to endourology

Purpose:

To analyze the 3-dimensional intrarenal anatomy of horseshoe kidneys (HK) and kidney with complete ureteral duplication (CUD), in polyester resin endocasts of the collecting system and in patients submitted to 3D computerized tomography scan (CT-scan).

Materials and Methods:

We analyzed seven 3-dimensional polyester resin endocasts of the kidney collecting system obtained from 6 fresh adult cadavers (4 with unilateral CUD and 2 with horseshoe kidney) and CT-scan reconstruction images of kidneys from 24 patients: 6 patients with HK, 8 with CUD and 10 patients without renal anomalies that were used as controls. We analyzed the spatial distribution of the calices, the infundibula diameters, the angle between the lower infundibulum and the renal pelvis (LIP) and the angle between the lower infundibulum and the inferior minor calyces (LIICA). Measurements of the width and length of the inferior infundibulum and the infundibula of the minor calyces, as well as the angles (LIP and LIICA) were made with the aid of the LibreOffice 6.3 software. The data were analyzed with the IBM^® SPSS^® Statistics.

Results:

There was no statistical difference in the inferior pole measurements between the groups with anomalies and the control group, both in polyester resin endocasts and CT-scan reconstruction images for LIP. When we compared the LIP in the CT-scan between HK versus CUD (p= 0.003), and HK versus the control group (p= 0.035), we observed statistical difference.

Conclusions:

The knowledge of spatial anatomy of lower pole is of utmost importance during endourologic procedures in patients with kidney anomalies. In the present study we observed that horseshoe kidneys had more restrictive anatomic factors in lower pole than the complete ureteral duplication.

Comparison of the Efficacy and Safety of Extracorporeal Shock Wave Lithotripsy and Flexible Ureteroscopy for Treatment of Urolithiasis in Horseshoe Kidney Patients: A Systematic Review and Meta-Analysis

Background: Urolithiasis is the most common complication of horseshoe kidney (HK), which can be treated by extracorporeal shock wave lithotripsy (ESWL), flexible ureteroscopy (FURS), and percutaneous nephrolithotomy (PCNL). When comparing treatments of ESWL and FURS, it is unclear which is more efficient and safe. The objective of this study was to compare the efficacy and safety of FURS and SWL for the treatment of urolithiasis in HK patients. Methods: A systematic search of the Web of Science, PubMed, and EMBASE was performed in February 2021. Newcastle-Ottawa Scale (NOS) was used to assess the risk of bias in each study. Results: Five studies published between 2008 and 2018 were synthesized in the present meta-analysis. The study revealed that FURS compared with SWL had greater initial and overall stone-free rates (SFRs). Risk ratios (RRs) were 2.46 (P < 0.00001) in initial SFRs, 1.36 (P = 0.02) in overall SFRs. No differences were found in the retreatment ratio, RRs were 0.49 (P = 0.43). In addition, no major complications were encountered, and all the complications were mild to moderate. Conclusion: The study demonstrated that FURS and SWL are effective and safe treatments for patients with HK with stones (<20 mm). Moreover, FURS has greater clearance rates and lower complication rates than SWL.

Real-world Global Outcomes of Retrograde Intrarenal Surgery in Anomalous Kidneys: A High Volume International Multicenter Study

OBJECTIVE

To analyze the trends and outcomes of retrograde intrarenal surgery for treatment of urolithiasis in anomalous kidneys in a large international multicenter series.

MATERIALS AND METHODS

We designed a multicentric retrospective study. Nineteen high-volume centers worldwide were included. Pre-, peri- and postoperative data were collected, and a subgroup analysis was performed according to renal anomaly.

RESULTS

We analyzed 414 procedures: 119 (28.7%) were horseshoe kidneys, 102 (24.6%) pelvic ectopic kidneys, 69 (16.7%) malrotated kidneys and 50 (12.1%) diverticular calculus. The average size (SD) of the stone was 13.9 (±6) millimeters and 193 (46.6%) patients had a pre-operative stent. In 249 cases (60.1%) a disposable scope was used. A UAS (ureteral access sheath) was used in 373 (90%) patients. A Holmium laser was used in 391 (94.4%) patients. The average (SD) operating time was 65.3 (±24.2) minutes. Hematuria, caliceal perforation and difficulty in stone localisation were mostly seen in diverticular stones and difficulty in UAS placement and lithotripsy in the cases of renal malrotation. The overall complication rate was 12%. Global stone-free rate was 79.2%. Residual fragments (RF) were significantly lesser in the pre-stented group (P <.05). Diverticular calculi was the group with more RF and needed ancillary procedures (P <.05).

CONCLUSION

Retrograde intrarenal surgery in patients with anomalous kidneys is safe and effective with a high single-stage stone-free rate and low complication rate. There is a trend toward using smaller and disposable scopes and smaller UAS. Diverticular stones can still be challenging with higher rates of intraoperative hematuria, caliceal perforation and RF.

Alternating Biplanar Fluoroscopy in Percutaneous Nephrostomy to Approach Stones in Patients With Horseshoe Kidney: An Institutional Experience

This case series aims to evaluate the use of alternating perpendicular biplanar fluoroscopy in percutaneous nephrostomies/percutaneous nephrolithotripsies (PCNs/PCNLs) to approach renal stones in patients with horseshoe kidneys. Between January 2012 and December 2019, PCNs/PCNLs were done for six patients with horseshoe kidneys having renal stones. Skin and renal calyceal entry points were determined by alternating perpendicular biplanar fluoroscopy using a portable C-arm machine in the conventional fluoroscopy unit. The site of renal access, postoperative complications, and residual stones was assessed.

The mean age of the patients was 36.8 years. The mean stone size was 6.1 cm (2.1-16.05cm). In five out of six (5/6; 83%) patients, there was one access site. Four patients had their access site through the upper calyx, and one patient had it through the lower calyx. The stone-free rate was four out of six (4/6; 66.6%). One patient had a mild drop in hemoglobin postoperatively. There were no major complications reported.

The implementation of alternating biplanar fluoroscopy was found safe and helpful in providing a better appreciation of renal anatomy and stone location in patients with horseshoe kidneys. This technique helps in approaching horseshoe kidney stones in PCN/PCNL without moving the patient or fluoroscopy machine, with a potential decrease in operation time and radiation exposure.

Supine tubeless PCNL in horseshoe kidney (a series of cases)

OBJECTIVE

Objective of this case series is accurate access to the respective calyx with stone in horseshoe kidney while performing percutaneous nephrolithotmy in supine position. Reducing operative time and anaesthetic morbidity while performing percutaneous nephrolithotomy in horseshoe kidney with nephrolithiasis in supine position.

MATERIALS AND METHODS

Four patient with one having bilateral renal calculi with horshoe kidney were selected randomly. There were no preference for age, gender; size, location and laterality of stone or BMI. All the patients fit into the AUA guideline criteria for management by percutaneous nephrolithotomy. Preoperative, perioperative and follow up data were collected.

RESULTS

Four patients with one having bilateral renal calculi underwent supine tubeless PCNL in 1 year in GMSV position. There was no intraoperative, post operative or on follow up complications in any patient. In all the patients stones were cleared completely in single setting.

CONCLUSION

Supine percutaneous nephrolithotomy in horseshoe kidney is an alternative to the standard prone percutaneous nephrolithotomy in the horseshoe kidney. It provides an additional benefit of performing the procedure in a single position, which is known to reduce total operating time, less anaesthesia related complications and less neuromusculoskeletal injury.

The robot-assisted ureteral reconstruction in adult: A narrative review on the surgical techniques and contemporary outcomes

Despite the rapid increase in the use of robotic surgery in urology, the majority of ureteric reconstruction procedures are still performed using laparoscopic or open approaches. This is primarily due to uncertainty regarding the advantages of robotic approaches over conventional ones, and the unique difficulty in identifying the specific area of interest due to the lack of tactile feedback from the current robotic systems. However, with the potential benefits of minimal invasiveness, several pioneering reports have been published on robotic surgery in urology. By reviewing the literature on this topic, we aimed to summarize the techniques, considerations, and consistent findings regarding robotic ureteral reconstruction in adults. Robotic applications for ureteral surgery have been primarily reported for pediatric urology, especially in the context of relieving a congenital obstruction in the ureteral pelvic junction. However, contemporary studies have also consistently demonstrated that robotic surgery could be a reliable option for malignant, iatrogenic, and traumatic conditions, which generally occur in adult patients. Nevertheless, the lack of comparative studies on heterogeneous hosts and disease conditions make it difficult to determine the benefit of the robotic approach over the conventional approach in the general population; thus, qualified prospective trials are needed for wider acceptance. However, contemporary reports have demonstrated that the robotic approach could be an alternative option for ureteral construction, even in the absence of haptic feedback, which can be compensated by various surgical techniques and enhanced three-dimensional visualization.

Retroperitoneal vs transperitoneal laparoscopic lithotripsy of 20-40 mm renal stones within horseshoe kidneys

BACKGROUND

Horseshoe kidney (HK) with renal stones is challenging for urologists. Although both retroperitoneal and transperitoneal laparoscopic approaches have been reported in some case reports, the therapeutic outcome of retroperitoneal compared with transperitoneal laparoscopic lithotripsy is unknown.

AIM

To assess the efficacy of laparoscopic lithotripsy for renal stones in patients with HK.

METHODS

This was a retrospective study of 12 patients with HK and a limited number (n ≤ 3) of 20-40 mm renal stones treated with either retroperitoneal or transperitoneal laparoscopic lithotripsy (June 2012 to May 2019). The perioperative data of both groups were compared including operation time, estimated blood loss, postoperative fasting time, perioperative complications and stone-free rate (SFR).

RESULTS

No significant difference was observed for age, gender, preoperative symptoms, body mass index, preoperative infection, hydronephrosis degree, largest stone diameter, stone number and isthmus thickness. The mean postoperative fasting time of the patients in the retroperitoneal group and the transperitoneal group was 1.29 ± 0.49 and 2.40 ± 0.89 d, respectively (P = 0.019). There was no significant difference in operation time (194.29 ± 102.48 min vs 151.40 ± 39.54 min, P = 0.399), estimated blood loss (48.57 ± 31.85 mL vs 72.00 ± 41.47 mL, P = 0.292) and length of hospital stay (12.14 ± 2.61 d vs 12.40 ± 3.21 d, P = 0.881) between the retroperitoneal and transperitoneal groups. All patients in both groups had a complete SFR and postoperative renal function was within the normal range. The change in estimated glomerular filtration rate (eGFR) from the preoperative stage to postoperative day 1 in the retroperitoneal group and the transperitoneal group was -3.86 ± 0.69 and -2.20 ± 2.17 mL/(min·1.73 m²), respectively (P = 0.176). From the preoperative stage to the 3-mo follow-up, the absolute change in eGFR values for patients in the retroperitoneal group and the transperitoneal group was -3.29 ± 1.11 and -2.40 ± 2.07 mL/(min·1.73 m²), respectively (P = 0.581).

CONCLUSION

Both retroperitoneal and transperitoneal laparoscopic lithotripsy seem to be safe and effective for HK patients with a limited number of 20-40 mm renal stones.

Investigation of Factors Related to Percutaneous Nephrolithotomy Failure in Horseshoe Kidneys and Comparison of Three Stone Scoring Systems in Prediction of Outcomes

INTRODUCTION

We aimed to identify factors affecting percutaneous nephrolithotomy (PNL) outcomes among patients with horseshoe kidney (HSK) and assess the predictive accuracy of the Clinical Research Office of the Endourological Society (CROES), Guy's Stone Score (GSS), and S.T.O.N.E. scoring systems.

METHODS

Data from 98 patients with HSK who underwent PNL between November 2010 and January 2020 were evaluated. Patients were divided into the stone-free (SF) and non-SF groups and compared according to demographic data, stone and surgical characteristics, and stone scoring systems. Multivariate logistic regression analysis was performed to identify factors associated with SF status.

RESULTS

Among the included patients, 87 were male and 11 were female (mean age: 47.37 ± 14.42 years). The SF rate was 84.7% (83 patients). Group analysis identified GSS (p < 0.001), CROES score (p < 0.001), S.T.O.N.E. score (p = 0.014), stone burden (p = 0.045), and multiplicity (p < 0.001) as factors associated with SF status. Among our cohort, 10 patients developed complications. All scoring systems were significantly correlated with SF status (CROES: r = -0.442, p < 0.001; GSS: r = 0.442, p < 0.001; S.T.O.N.E.: r = 0.250, p = 0.013), while CROES score was identified as an independent factor associated with SF status (95% CI: 0.937-0.987; p = 0.003).

CONCLUSIONS

PNL is an effective method for treating nephrolithiasis among patients with HSK. Moreover, stone-related factors, such as larger size, multiplicity, and complexity, were associated with procedural failure. Finally, the CROES nomogram was a better predictor of SF status compared with other scoring systems.

Laparoscopy combining with ureteroscopy for horseshoe kidney accompanying with duplicate kidney and a ureteral calculus: a case report

BACKGROUND

Horseshoe kidney (HSK) is a common renal fusion anomaly, occurring in about 1 in 400-600 individuals. In addition, the incidence of duplicated collecting system is about 0.8%.

CASE PRESENTATION

This report documents an extremely rare case, which was treated by multiple procedures in the same operative session to accomplish laparoscopic amputation of the HSK isthmus, resection of duplicate kidney and ureteroscopic lithotripsy.

CONCLUSION

Results showed that minimally invasive surgery with use of multiple endoscopes may be a feasible choice for this patient population with complicated comorbid renal conditions.

Management of staghorn stones in special situations

Staghorn stones have always been a challenge for urologists, especially in some special situations, such as horseshoe kidney, ectopic kidney, paediatric kidney, and solitary kidney. The treatment of these staghorn stones must be aggressive because they can lead to renal function loss and serious complications. The gold-standard management for staghorn stones is surgical treatment with the aim of clearing the stones and preserving renal function. Treatment methods for staghorn stones have developed rapidly, such as extracorporeal shock wave lithotripsy, retrograde intrarenal surgery, percutaneous nephrolithotomy and laparoscopy and open surgery. Whether the standard procedures for staghorn stones can also apply to these stones in special situations is still not agreed upon. The decision should be made individually according to the circumstances of the patient. In this review, we evaluates the previous studies and comments on the management of staghorn stones under special situations in the hope of guiding the optimal choice for urologists.

Laparoscopy-Assisted Transperitoneal Percutaneous Nephrolithotomy for the Treatment of Renal Stones in a Horseshoe Kidney

The objective of this case report is to highlight treatment by LAT-PCNL in a patient with horseshoe kidney. A 51-year-man with hematuria presented to the emergency department with moderate abdominal pain starting 7 hrs ago. He did not report a history of previous urological disease. Renal stone and horseshoe kidney malformation were diagnosed based on the plain abdominal film, intravenous urogram (IVU), non-contrast computed tomography (CT-IVU), and ultrasound findings. Due to the larger stone bulk and renal malformation, it was not possible to perform extracorporeal shock wave lithotripsy (ESWL) monotherapy or ESWL sandwich therapy. Moreover, since percutaneous nephrolithotomy (PCNL) had some challenges and limitations due to high skin-to-stone distance, special anatomy, dispersion stones, and possible consequent internal organs injuries, we performed LAT-PCNL on our patient. We did not observe any perioperative complication. Postoperative control abdominal x-ray revealed only a medium ureteral stone that was extracted while removing the Double-J stent a month later. The patient was discharged on the third postoperative day with normal laboratory values. At 3-month follow-up, the patient was stone-free with normal renal function and renal ultrasonography. Laparoscopy-assisted transperitoneal PCNL seems to be a safe and minimally invasive technique that can be used as an alternative approach in the management of renal stones in special cases of horseshoe kidneys.

Retroperitoneoscopic nephrectomy for a horseshoe kidney with hydronephrosis and inflammation: A case report

RATIONALE

A horseshoe kidney is the most common congenital fusion abnormality in the kidney, occurring in approximately 1 in 400 live births. Several complications including renal malignancies, ureteropelvic junction obstruction, urolithiasis, vesicoureteral reflux, and hydronephrosis can occur in this patient population.

PATIENT CONCERNS

A 28-year-old woman was admitted to hospital because of chronic left low back pain. Microscopic hematuria was not seen. Computed tomography showed the horseshoe kidney and left hydronephrosis.

DIAGNOSES

On the basis of these findings and clinical manifestations, the final diagnosis was the horseshoe kidney with left renal hydronephrosis and inflammation.

INTERVENTIONS

A retroperitoneoscopic nephrectomy on the left kidney was performed.

OUTCOMES

Histopathological examination of the specimen confirmed massive dilatation of the pelvicaliceal system and chronic pyelonephritic inflammation. The patient was discharged on the 7th postoperative day with no complications and no back pain. She remained well at 3 months with normal activity and good cosmetic result.

LESSONS

Retroperitoneoscopic nephrectomy can be a safe and minimally invasive surgery for horseshoe kidney treatment.

Establish new formulas for the calculation of renal and isthmus depth in horseshoe kidney

This study was performed to develop a new formula to estimate the renal and isthmus depth in horseshoe kidney, and to compare the new formula with previously published formulas.Renal depth, isthmus depth, vertebral thickness, and total thickness (T, cm) of the body at the level of the kidneys were measured by CT in 124 adults. Their sex, age, height (H, cm), and weight (W, kg) were recorded. Multiple stepwise linear regression analysis was conducted. The 124 cases were divided into 2 random groups, of which the first group was used to derive a regressive formula and the second group was used to verify the formula and compare the formula with previously published formulas.Multiple stepwise linear regression analysis showed that the important variables in estimating the depth of each kidney were the body weight (W, kg) and the total thickness (T, cm) of the body at the level of the kidneys. The important variables in estimating the depth of isthmus soft tissue and vertebral thickness were W, T, and age, W. The new formula was the following: right renal depth (cm) = 0.273 × T + 0.043 × W + 1.086 (r = 0.82, P < .05; standardized regressive coefficient: T = 0.500, W = 0.367), left renal depth (cm) = 0.245 × T + 0.041 × W + 0.676 (r = 0.83, P < .05; standardized regressive coefficient: T = 0.520, W = 0.353); isthmus depth (cm) = soft tissue depth + vertebral thickness, soft tissue depth (cm) = 0.144 × T + 0.044 × W + 0.536 (r = 0.58, P < .05; standardized regressive coefficient: T = 0.272, W = 0.335), vertebral thickness (cm) = 0.012 × age + 0.018 × W + 3.683 (r = 0.53, P < .05; standardized regressive coefficient: age = 0.326, W = 0.438). It is much better than the literatures.The new renal depth estimation formula in horseshoe kidney that we derived by using multiple stepwise linear regression has greatly outperformed other 6 previously published formulas. Isthmus depth estimation formula can also get accurate results. Our new formula provides a more reliable and accurate renal and isthmus depth estimation and contributes to improving the methods used to estimate renal function from radionuclide renography in horseshoe kidney.

Robot-assisted laparoscopic pyeloplasty (RALP) in children with horseshoe kidneys: results of a multicentric study

PURPOSE

This multicentric study aimed to report our experience with robot-assisted laparoscopic pyeloplasty (RALP) in children with horseshoe kidney (HSK).

METHODS

The records of 14 patients (11 boys and 3 girls with an average age of 9 years), who underwent RALP for repair of pelvi-ureteric junction obstruction (PUJO) in HSK in five international pediatric urology units over a 5-year period, were retrospectively reviewed. A dismembered pyeloplasty with no division of isthmus was performed in all the cases.

RESULTS

The average operative time including docking was 143.5 min (range 100-205). No conversions to laparoscopy or open surgery or intra-operative complications occurred. Patients were discharged on postoperative day 2 following catheter and drain removal. The JJ stent was removed at mean 33 days postoperatively. Overall success rate was 92.8%. As for postoperative complications, we recorded a urinary tract infection (UTI) and stent-related irritative symptoms, managed with medical therapy, in two patients (II Clavien) and an anastomotic stricture in one patient needing surgical revision with no further recurrence (IIIb Clavien). At follow-up, all the patients (one after redo-surgery) reported complete resolution of symptoms, improvement of hydronephrosis on ultrasound and no residual obstruction on diuretic renogram.

CONCLUSIONS

Our experience suggested that RALP in HSK is safe, feasible and with good medium-term outcomes in expert hands. An accurate pre-operative planning associated with a standardized technique is key points to achieve good surgical and functional outcomes in these challenging cases. The da Vinci robot technology offers the advantages of MIS procedures and overcomes the technical challenges of laparoscopic approach.

Changing trends in the endourological management of urolithiasis in anomalous kidneys

OBJECTIVES

To present our single-centre experience of urolithiasis management in anomalous kidneys, highlighting the need for an algorithm-based approach in deciding the appropriate treatment method for each type.

PATIENTS AND METHODS

We retrospectively reviewed the data of all the patients who presented to our renal unit with urolithiasis in an anomalous kidney between January 1990 and July 2014. The peri-operative characteristics of all the patients, along with management approach, were studied.

RESULTS

Percutaneous nephrolithotomy (PCNL) was the most common surgical technique used, followed by flexible ureterorenoscopy (URS). Pain was the most common presentation in these patients. The overall stone clearance rate associated with PCNL and flexible URS was 85.8% in cases of anomalous kidneys in this series. The stone clearance rates in ectopic kidneys, horseshoe kidneys, malrotated kidneys and autosomal dominant polycystic kidneys associated with PCNL and flexible URS were similar: 86%, 88%, 76% and 83%, respectively, and 81.2%, 80%, 92% and 100%, respectively . Based on our results, we developed a stone management algorithm.

CONCLUSION

The management of renal calculi in patients with renal anomalies may vary based on the stone size, location, density, pelvicalyceal system anatomy and drainage. An algorithm-based approach could help surgeons decide the appropriate treatment in this population.

Use of MR Urography in Pediatric Patients

PURPOSE OF REVIEW

In this article, we describe the basics of how magnetic resonance urography (MRU) is performed in the pediatric population as well as the common indications and relative performance compared to standard imaging modalities.

RECENT FINDINGS

Although MRU is still largely performed in major academic or specialty imaging centers, more and more applications in the pediatric setting have been described in the literature. MRU is a comprehensive imaging modality for evaluating multiple pediatric urologic conditions combining excellent anatomic detail with functional information previously only available via renal scintigraphy. While generally still reserved for problem solving, MRU should be considered for some conditions as an early imaging technique.

Retrograde intrarenal surgery: An expanding role in treatment of urolithiasis

During the past 3 decades, the surgical management of kidney stones has undergone many technological advances and one is the development of the flexible ureteroscopy. The development of this instrument as well as ancillary equipment such as baskets, graspers, and others, and improvements in lithotripsy with Holmium: YAG laser have led to expand its indications with diagnostic and therapeutic management of medical issues of the upper urinary tract such as urolithiasis and urothelial tumors. The objective of this review is to describe its indications and results in the different scenarios for the treatment of urinary stones.

Transperitoneal laparoscopic pyeloplasty in children: does upper urinary tract anomalies affect surgical outcomes?

OBJECTIVE

To assess the feasibility and outcomes of laparoscopic pyeloplasty in children with complex ureteropelvic junction obstruction (UPJO) and compare to children with iso-lated UPJO without associated urinary tract abnormalities.

MATERIAL AND METHODS

Medical records of 82 consecutive children submitted to transperitoneal laparoscopic pyeloplasty in a 12-year period were reviewed. Eleven cases were con-sidered complex, consisting of atypical anatomy including horseshoe kidneys in 6 patients, pelvic kidneys in 3 patients, and a duplex collecting system in 2 patients. Patients were di-vided into 2 groups: normal anatomy (group 1) and complex cases (group 2). Demographics, perioperative data, outcomes and complications were recorded and analyzed.

RESULTS

Mean age was 8.9 years (0.5-17.9) for group 1 and 5.9 years (0.5-17.2) for group 2, p=0.08. The median operative time was 200 minutes (180-230) for group 1 and 203 minutes (120-300) for group 2, p=0.15. Major complications (Clavien ≥3) were 4 (5.6%) in group 1 and 1 (6.3%) in group 2, p=0.52. No deaths or early postoperative complications such as: urinoma or urinary leakage or bleeding, occurred. The success rate for radiologic improvement and flank pain improvement was comparable between the two groups. Re-garding hydronephrosis, significant improvement was present in 62 patients (93.4%) of group 1 and 10 cases (90.9%) of group 2, p=0.99. The median hospital stay was 4 days (IQR 3-4) for group 1 and 4.8 days (IQR 3-6) for group 2, p=0.27.

CONCLUSIONS

Transperitoneal laparoscopic pyeloplasty is feasible and effective for the management of UPJO associated with renal or urinary tract anomalies.

Role of magnetic resonance urography in pediatric renal fusion anomalies

Renal fusion is on a spectrum of congenital abnormalities that occur due to disruption of the migration process of the embryonic kidneys from the pelvis to the retroperitoneal renal fossae. Clinically, renal fusion anomalies are often found incidentally and associated with increased risk for complications, such as urinary tract obstruction, infection and urolithiasis. These anomalies are most commonly imaged using ultrasound for anatomical definition and less frequently using renal scintigraphy to quantify differential renal function and assess urinary tract drainage. Functional magnetic resonance urography (fMRU) is an advanced imaging technique that combines the excellent soft-tissue contrast of conventional magnetic resonance (MR) images with the quantitative assessment based on contrast medium uptake and excretion kinetics to provide information on renal function and drainage. fMRU has been shown to be clinically useful in evaluating a number of urological conditions. A highly sensitive and radiation-free imaging modality, fMRU can provide detailed morphological and functional information that can facilitate conservative and/or surgical management of children with renal fusion anomalies. This paper reviews the embryological basis of the different types of renal fusion anomalies, their imaging appearances at fMRU, complications associated with fusion anomalies, and the important role of fMRU in diagnosing and managing children with these anomalies.

Flexible ureterorenoscopy in position or fusion anomaly: Is it feasible?

OBJECTIVE

To analyze the results of flexible ureterorenoscopy (F-URS) with holmium laser in the treatment of kidney stones with ectopic and fusion anomalies (horseshoe kidney and rotation anomalies).

METHOD

We reviewed data from 13 patients with fusion and ectopic renal anomalies that underwent F-URS from April 2011 to April 2017. We analyzed demographic and clinical data (age, gender, BMI, anatomical abnormality, location and dimension of the renal calculi) and perioperative data (method of treatment, stone-free rate, number of days with DJ catheter and perioperative complications).

RESULTS

The mean stone size was 12.23 +/- 5.43 mm (range 6-22mm), located in the inferior (58.33%) and middle (16.76%) calyceal units, renal pelvis (16.67%) and multiple locations (8.33%). All 13 patients were treated with Ho-Yag laser, using dusting technique (25%), fragmentation and extraction of the calculi (58.33%) and mixed technique (16.67%). We did not have any severe perioperative complication. After 90 days, nine patients (75%) were considered stone free.

CONCLUSION

Our data suggest that F-URS is a safe and feasible choice for the treatment of kidney stones in patients with renal ectopic and fusion anomalies.

Hybrid Repair of an Abdominal Aortic Aneurysm: Debranching with Endovascular Aneurysm Repair in a Patient with Horseshoe Kidney

Abdominal aortic aneurysm (AAA) with associated horseshoe kidney (HSK) poses a technical challenge when performing conventional open surgical repair because of possible complications including renal infarction, neuralgia, and collecting system disruption. Endovascular aortic repair (EVAR) is considered the first-line treatment for this pathology, allowing for aneurysm repair without isthmus bisection. However, whether to sacrifice commonly presenting aberrant renal arteries during EVAR is a point of controversy. We report a case in which hybrid repair was performed for AAA to preserve aberrant renal vasculature in a patient with HSK.

Bilateral duplex urinary collecting systems accompanied with horseshoe kidneys deformity and right renal ureteral calculi and hydronephrosis: Diagnosis in magnetic resonance urography

Horseshoe kidney deformity with duplex urinary collecting systems is a rare congenital urinary tract defect. Clinically, it is very difficult to visually observe and examine the whole anatomic structure and information with the regular 2D diagnostic imaging tools. Here, we report a case in which a middle age patient has bilateral duplex urinary collecting systems and horseshoe kidney deformity accompanied with right renal ureteral calculi and hydronephrosis. It was diagnosed by magnetic resonance urography with urinary system 3D reconstruction. The imaging and display method provides valuable information about abnormal anatomic structures of the kidneys and the related stone diseases for preoperative planning.

Flexible Ureteroscopic Management of Horseshoe Kidney Renal Calculi

PURPOSE

To evaluate the clinical efficacy of flexible ureteroscope (F-URS) combined with holmium laser lithotripter in treating renal calculi in horseshoe kidney.

MATERIALS AND METHODS

From November 2010 to December 2013, the medical history and charts of sixteen patients (mean age 42.9 ± 11.6 years, range 26-66 years), including 13 males and 3 females were analyzed retrospectively. Mean stone burden was 29 ± 8 mm (range 17-42 mm2). Mean stone digitized surface area (DSA) was 321 ± 94 mm2 (range 180-538 mm2). Under spinal anesthesia in a modified lithotomy position with the head down, rigid ureteroscope was placed firstly into the ureter to reach the level of the pelvis, a zebra guide wire was inserted and following the removal of the rigid ureteroscope, an ureteral access sheath was positioned along the guide wire, then passed the URF P-5 flexible ureteroscope into the renal cavities over the guidewire. After locating the stones, holmium laser lithotripsy was performed.

RESULTS

The average operative time was 92 ± 16 minutes (range 74-127 min.). No major complications were encountered. Ten patients obtained stone-free status with one session, four obtained stone-free status after two sessions. Single session stone-free rate was 62.5%, overall stone-free rate was 87.5%. Two patients have small residual stones in the lower pole.

CONCLUSIONS

F-URS combined with holmium laser lithotripter and nitinol basket, is safe and effective in dealing with moderate stone diameter (<30 mm) in HSKs with high clearance rates and low complication rates.

Endoscopic Management of Urolithiasis in the Horseshoe Kidney

OBJECTIVE

To assess the endourologic outcomes of patients diagnosed with a horseshoe kidney (HK) and symptomatic urolithiasis.

METHODS

A retrospective review was performed of patients diagnosed with an HK who underwent endoscopic management from 2002 to present.

RESULTS

We identified 45 patients with 64 stone-bearing moieties who underwent 56 procedures, of which 31 (69%) were male. Mean age was 49.4 years (23-78) and mean stone size was 1.6 cm (0.2-5.7). Of the 64 moieties, 37 (58%) underwent percutaneous nephrolithotomy (PCNL), 25 (39%) underwent ureteroscopy (URS), and 2 (3%) underwent extracorporal shockwave lithotripsy (SWL). More than one access was utilized in 2 (5.7%) moieties undergoing PCNL. Additional procedures were required in 10 (28.5%) PCNL patients, of which 7 were URS, 2 were secondary PCNL, and 1 sandwich therapy with SWL and PCNL. Stone-free rate by moiety was 81.1% for PCNL, 84% for URS, and 50% for SWL. Postoperative complications occurred in 3 patients in the PCNL group, including readmission for pain and complicated urinary tract infection. With a mean follow-up of 20.5 months (range 0-118 months), stone recurrence was noted in 7 (16%) patients with a total of 11 events. Calcium oxalate was the most common stone type and 20/24 (83%) of patients with metabolic evaluations were found to have at least one abnormality.

CONCLUSION

After careful consideration of the anatomy, individuals with HK and symptomatic urolithiasis can be managed safely by a variety of endoscopic approaches with excellent outcomes; however, secondary procedures and recurrence are common.

The Robotic-Assisted Laparoscopy, Isthmusectomy, and Pyeloplasty in a Patient With Horseshoe Kidney: A Case Report

The aim of this case report was to evaluate the results of isthmusectomy and pyeloplasty of horseshoe kidney with the da Vinci robotic-assisted laparoscopy system.This case presented 1 patient with left back pain, associated with lower abdominal pain, and then she underwent the isthmusectomy and dismembered pyeloplasty using robotic-assisted laparoscopy simultaneously. The operation was performed by a transperitoneal approach using 5 ports.We cut the renal isthmus by means of bipolar scissors and then closed the renal parenchyma with 3-0 absorbed stitches. The total operation time was 123 min including simultaneous dismembered pyeloplasty. Blood loss was <50 mL. There were no complications either during or after the procedure. The oral nutrition and mobilization were included on the second day after surgery. The peritoneal drainage was removed on the eighth day. Long-term follow-up after treatment showed good results.The da Vinci robotic-assisted laparoscopy is an alternative to open surgery and laparoscopy, particularly in the correction of congenital defects of the urinary tract. Furthermore, the da Vinci robotic-assisted laparoscopy technique in isthmusectomy and pyeloplasty is safe for patient as shown by our results.

Glomerular filtration rate measured by (99m) Tc-DTPA renal dynamic imaging is significantly lower than that estimated by the CKD-EPI equation in horseshoe kidney patients

AIM

Gate's glomerular filtration rate (gGFR) measured by (99m) Tc-DTPA renal dynamic imaging and estimated GFR (eGFR) estimated by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation are two indexes used to evaluate renal function. However, little is known about whether gGFR can be used to accurately assess renal function in horseshoe kidney (HSK) patients with renal fusion anomalies.

METHODS

Nineteen HSK patients (HSK group) diagnosed by renal imaging and 38 CKD patients with "normal kidney shape" (non-HSK group) matched to the HSK patients in terms of gender, age and biochemical indicators at Chinese PLA General Hospital were enrolled in this study. Gender, age, serum total protein (TP), albumin (ALB), blood urea nitrogen (BUN), serum creatinine (Scr), gGFR and eGFR were recorded and analyzed using χ(2) test, t-test, and Wilcoxon test which was presented as median(IQR).

RESULTS

(1) There were no significant differences in gender, age, TP, ALB, BUN, Scr, or eGFR between these two groups. (2) In HSK patients, the renogram showed abnormal renal axis with the lower poles orientated medially. The timed uptake curve showed that the isotope excretion in the HSK group was slower than that in the non-HSK group. (3) For all HSK patients, gGFR was significantly lower than eGFR (range -12.52 mL/min per 1.73m(2) to -93.18 mL/min per 1.73m(2) ). There was no significant difference in eGFR between the HSK [96.42 (36.02) mL/min per 1.73 m(2) ] and non-HSK groups [94.46 (33.00) mL/min per 1.73 m(2) ]. The gGFR of the HSK group [41.18 (16.60) mL/min per 1.73m(2) ] was much lower than that of the non-HSK group [86.42(26.40) mL/min per 1.73m(2) , P < 0.001] and the eGFR of the HSK group (P < 0.001). The gGFR and eGFR of the non-HSK group were not significantly different.

CONCLUSION

gGFR measured by (99m) Tc-DTPA renal dynamic imaging is significantly lower than eGFR estimated by the CKD-EPI equation, which indicates that isotope renogram cannot accurately evaluate the GFR of HSK patients.

Laparoscopic pyeloplasty in children with horseshoe kidney

PURPOSE

Laparoscopic pyeloplasty for ureteropelvic junction obstruction associated with horseshoe kidney has been described in adults but seldom in young children. We describe our experience in 10 children treated successfully with laparoscopic dismembered pyeloplasty.

MATERIALS AND METHODS

Eight boys and 2 girls with a mean age of 8 years (range 0.7 to 16.5) underwent laparoscopic dismembered pyeloplasty for ureteropelvic junction obstruction associated with horseshoe kidney between 2002 and 2012. Presenting symptoms were abdominal pain (3 patients), urinary tract infection (2), abdominal mass (1) and hematuria (1). Horseshoe kidney was diagnosed preoperatively in all cases but 1. The anastomosis was done by running or interrupted 5-zero or 6-zero resorbable sutures and drained by a Double-J® stent.

RESULTS

Laparoscopic dismembered pyeloplasty was feasible in all cases. Mean operating time was 220 minutes (range 180 to 260). Anatomical abnormalities included anteriorly crossing vessels at the ureteropelvic junction in 6 cases (polar vessels in 4, ureteropelvic junction posterior to an abnormal branch of vena cava in 1 and renal vein in 1) and high ureteral insertion in 4. Two children underwent an extensive reduction pyeloplasty. Mean hospital stay was 3.2 days (range 1 to 8). Mean followup was 50 months (range 4 to 132). All patients were asymptomatic with significant improvement of dilatation.

CONCLUSIONS

The transperitoneal laparoscopic approach is adapted for pyeloplasty in children with horseshoe kidney. This procedure allows global exploration of the upper tract and efficient identification of anatomical anomalies, especially crossing vessels. Although our series is small, it is the first known description specific to horseshoe kidney in children and demonstrates that this approach has lasting effectiveness in young children.

Laparoscopic Anderson-Hynes pyeloplasty without symphysiotomy for hydronephrosis with horseshoe kidney

INTRODUCTION

The objective of this study is to clarify whether symphysiotomy is an essential procedure combined with the laparoscopic pyeloplasty for the surgical treatment of ureteropelvic junction obstruction related to horseshoe kidney.

METHODS

We retrospectively reviewed five horseshoe kidney patients with symptomatic hydronephrosis who underwent laparoscopic transperitoneal Anderson-Hynes pyeloplasty without symphysiotomy between July 2002 and October 2011.

RESULTS

All procedures were completed successfully without open conversion. Mean operative time and estimated blood loss were 209 min and 40 mL, respectively. Anterior crossing vessels were observed in all cases, and four of them were defined as a principle cause of the obstruction. In the remaining case, intrinsic stenosis of the ureteropelvic junction was noted. Crossing vessels were transposed behind the ureter with ureteropelvic anastomosis at the anterior aspect of these structures. Preoperative symptoms were absent postoperatively in all cases. Diuretic renogram showed that renal function of the side with hydronephrosis was unchanged, but diuretic excretion half-time was diminished in all cases.

CONCLUSION

The present data suggest that symphysiotomy can be avoided in many, if not all, cases of hydronephrosis related to horseshoe kidney. Laparoscopic Anderson-Hynes pyeloplasty with transposition of anterior crossing vessels seems effective, especially if aberrant vessels are strongly suspected to be present from the preoperative imaging examination.

Retrograde intrarenal surgery in patients with horseshoe kidneys

Retrograde intrarenal surgery (RIRS) in patients with horseshoe kidneys (HSKs) remains poorly studied. The present study aimed to assess clinical success and stone-free rates in HSK patients with renal stones treated with flexible ureteroscopy. RIRS was attempted in 20 patients with 25 renal stones in HSK from December 2008 to January 2012. The patients were evaluated with imaging studies including plain abdominal radiography, intravenous urogram, abdominal ultrasonography or non-contrast tomography scan. Success rate was defined as stone-free or residual fragment less than 4 mm. Pre-operative, operative and postoperative data were retrospectively analyzed. A total of 20 patients were included in the present study (12 males, 8 females). 9 of 25 renal stones (36 %) were located in the lower calyx of the kidney, whereas 7 (28 %) in the middle calyx, 5 (20 %) in the renal pelvis and 4 (16 %) in the upper calyx. The mean stone size was 17.8 ± 4.5 mm. The stone-free rate was 70 % after a single procedure. 6 patients required shock wave lithotripsy and two of these were completely stone-free. Average hospital stay was 1.4 ± 0.7 days. Minor complications as classified by Clavien I or II occurred in 25 %. No major complications (Clavien III-V) occurred in the study group. RIRS is an effective and safe treatment modality for renal stones in patients with HSK. The procedure has minimal morbidity and high success rate.

[Surgical therapy of lithiasis in horseshoe kidney]

OBJECTIVE

To present our centre's experience in the surgical treatment of lithiasis in patients with horseshoe kidney.

MATERIAL AND METHODS

From October 2007 to March 2011 we treated 10 patients with renal lithiasis in their horseshoe kidneys. Retrospectively, we reviewed the symptoms, medical and surgical history, the characteristics of the stones (size, location, composition) and treatments that were carried out. In all the cases, the study was carried out by CT, with volume reconstruction and with an angiographic study. A percutaneous nephrolithotomy (PCNL) or an endoscopic retrograde intrarrenal surgery (RIRS) was carried out, depending on the size and location of the stone.

RESULTS

Three percutaneous nephrolithotomies were carried out (2 on staghorn lithiasis stones, 1 pseudocoraliform stone) with a combined rigid and flexible single-access nephroscopy. In one case there was haemorrhage that required treatment by selective embolization. In the rest, RIRS was carried out, all with stones < 30 mm in their greatest diameter without any complications. The mean surgical times were 120 (60-180) minutes for the percutaneous route and of 105 (65-160) minutes for the retrograde route. In all the cases the treatment achieved a complete elimination of the stones or remains of less than 5 mm.

CONCLUSIONS

The treatment of renal lithiasis in horseshoe kidneys is complex, given their peculiar anatomy. The usual surgical techniques can be reproduced in these cases with good results. We opt for PCNL in complete staghorn stone and pseudocoraiform stones, whereas RIRS is a valid option in cases with stones < 3 cm.

Percutaneous nephrolithotomy in horseshoe kidneys: factors affecting stone-free rate

PURPOSE

We report a 2-center study of factors affecting the stone-free rate after percutaneous nephrolithotomy in horseshoe kidneys.

MATERIALS AND METHODS

The postoperative stone-free rate after percutaneous nephrolithotomy was evaluated in 47 male and 11 female patients with horseshoe kidneys. All data were collected prospectively. Patient and procedure related factors predicting the stone-free rate were analyzed by univariate and multivariate tests.

RESULTS

The mean ± SD stone burden was 7.62 ± 7.18 cm(2) (range 1 to 45) and the stone was larger than 10 cm(2) in 14 patients (24.1%). Complex stones and staghorn stones were present in 21 (36.2%) and 19 patients (32.7%), respectively. The overall stone-free rate was 65.5%. Complex stones (p = 0.01), stone burden greater than 5 cm(2) (p = 0.013), stone burden greater than 10 cm(2) (p = 0.012), multiple stones (p = 0.006) and staghorn stones (p <0.001) were related to adverse outcomes on univariate analysis. Logistic regression analysis revealed that staghorn calculi was the only factor that significantly predicted the stone-free rate (p = 0.002). A patient with staghorn calculi in the horseshoe kidney was 45 times more likely to have a lower stone-free rate after percutaneous nephrolithotomy than a patient without staghorn calculi in the horseshoe kidney.

CONCLUSIONS

Stone parameters are important when treating calculi in horseshoe kidneys. Staghorn calculi are associated with a lower stone-free rate after percutaneous nephrolithotomy.

Giant renal calculus in a horseshoe kidney presenting as an abdominal lump

We report a case of giant renal calculus of 14 × 10.5 × 9 cm in size and weighing 790 g, in a horseshoe kidney, along with two large calculi on the opposite side. Patient presented with unusual complaint of an abdominal lump only. Physical examination revealed a stony hard mass on the left side of the abdomen, extending from the subcostal region to just above the iliac crest. A giant renal calculus on the left and two large calculi on the right side of a horseshoe kidney were diagnosed on computed tomography (CT) scan. Percutaneous nephrolithotomy, followed after 5 days by open pyelolithotomy was done for the stones on the right and left side, respectively. Analysis revealed a calcium phosphate stone. This case is worth reporting as it was not only the 8th heaviest renal stone reported in the English literature, but also the first giant stone to be reported in a horseshoe kidney.