Horseshoe Kidney Patients Research Articles

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

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. 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. 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 300mL, P=.004; 246 vs 163minutes, 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). 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.

Pathologic Findings and Management of Renal Mass in Horseshoe Kidneys

To evaluate the management, surgical outcomes, and pathological findings in patients with tumor in a horseshoe-kidney (HK). HK patients present unique challenges due to aberrant vascular anatomy and risk of renal insufficiency. We hypothesized that many tumors in this setting may be indolent or benign. Patients managed for renal mass in HK at our center (1999-2021) were reviewed. Baseline characteristics, surgical approach, complications, functional outcomes, pathology, and survival were analyzed. Forty-three procedures were performed in 42 patients with HK including 24 nephron-sparing surgeries (NSS) and 19 radical nephrectomies (RN: splitting the isthmus and saving the contralateral moiety). NSS included 22 partial nephrectomy (PN) and 2 thermal ablations. Median tumor size was 4.3 cm. Eighteen cases (42%) were minimally-invasive, 17 open-midline, and 8 other open approaches. Ninety-day Clavien III-V complication rate was 12% with no mortalities. For PN, median warm/cold ischemia times were 26/31 minutes, respectively. On pathology, only 27 tumors (63%) were renal-cell-carcinoma (RCC), and 22 tumors (51%) were either benign (n = 10) or low grade, confined RCC (n = 12). Preoperative/new baseline/long-term eGFR were 82/83/78 mL/min/1.73 m2 after NSS vs 75/48/57 mL/min/1.73 m2 after RN, respectively. Long-term dialysis was required in 3 patients (7%). Median follow-up was 36 months. Five-year recurrence-free survival was 83% for NSS and 66% for RN. Management of renal masses in HK is challenging and requires versatility with multiple surgical approaches. Preservation of renal function was accomplished in most patients, with a functional advantage observed for NSS. RCC was less common than expected while benign and non-aggressive tumors were prevalent, suggesting consideration for preoperative renal-mass-biopsy when feasible.

A retrospective analysis of ureteropelvic junction obstructions in patients with horseshoe kidney.

BackgroundUreteropelvic junction obstruction (UPJO) is often encountered in patients with a horseshoe kidney (HSK) and may require surgical intervention. This study retrospectively investigated obstruction causes in HSK patients with UPJOs to determine the most suitable surgical method.MethodsTwenty HSK patients with UPJO who underwent pyeloplasty between July 2000 and June 2020 and were followed-up for more than six months in our institution were included in the study. The clinical characteristics, obstruction causes, and surgical outcomes were analyzed.ResultsThe median age at the time of the operation was 4.1 years [interquartile range (IQR): 1.8–10.6]. Hydronephrosis (HN) was found prenatally in 5 patients (25.0%). Pyeloplasty was performed by open, laparoscopic, and robotic techniques in 6, 10, and 4 patients, respectively. Sixteen patients (80.0%) had high ureteral insertion. Twelve patients (60.0%) had crossing vessels, and eight had a high ureteral insertion and crossing vessels. The median follow-up duration was 4.0 years (IQR: 1.8–8.9); no patient required additional surgery. The median differential renal function was 38.0% (IQR: 16.9–43.0%) preoperatively and 38.0% (IQR: 13.3–48.2%) postoperatively.ConclusionsUPJOs in HSKs were primarily caused by a high ureteral insertion and crossing vessels. Dismembered pyeloplasty was successfully performed in all surgical modalities such as the open, laparoscopic, and robotic approaches. Attention must be given to patients with HSKs, even in those without HN, to avoid UPJO development.

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

BACKGROUNDHorseshoe 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. AIMTo assess the efficacy of laparoscopic lithotripsy for renal stones in patients with HK.METHODSThis 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).RESULTSNo 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).CONCLUSIONBoth retroperitoneal and transperitoneal laparoscopic lithotripsy seem to be safe and effective for HK patients with a limited number of 20-40 mm renal stones.

Presacral Anatomy in Women With a Horseshoe Kidney.

Horseshoe kidney (HSK) is the most common renal fusion defect that can alter vascular and upper urinary tract anatomy. Anatomic variations in the presacral space can make surgical dissection very challenging. The aim of this study was to characterize presacral anatomy in women with HSK. Large academic centers' database was queried to identify imaging studies in adult women with HSK. Available multiplanar computed tomography and magnetic resonance imaging images were reviewed, and relevant vascular and upper urinary tract anatomy was measured and compared with published normal values. Study population was compared with the normal controls using Student t test, χ test, or Fisher exact test as appropriate. One hundred seventy-eight women were identified initially, and 20 confirmed to have HSK on imaging. The mean ± SD age was 54.5 ± 16.9 years, and body mass index was 27.3 ± 7.5 kg/m. Women with HSK had a narrower angle of aortic bifurcation (39.1 ± 18.7 degrees vs 55.6 ± 4.5 degrees, P = 0.014); the right ureter was closer to midline (22.9 ± 8.8 mm vs 32.3 ± 1.2 mm, P < 0.001) when compared with normal controls anatomy. In 40% of women with HSK, the bifurcation of the vena cava was below the level of L5 in contrast to the 8% in the normal population (P < 0.001). In 60% of women with HSK, the inferior pole of the kidney was at or below L5. Ureteral, renal, and vascular anatomic alterations in women with HSK may make presacral surgical anatomy challenging by obscuring the anterior longitudinal ligament anchoring point. Preoperative imaging is warranted to determine the feasibility of female pelvic reconstructive surgery in HSK patients.

Management of Aortoiliac Aneurysms with Atypical Renal Artery Anatomy

Renal artery anomalies occur at a rate of 1-2% and present a challenge to vascular surgeons performing aortic surgery. We describe adjuncts used to manage such anatomic variants. A single surgeon registry of all abdominal aortic aneurysms repaired in an academic center was retrospectively reviewed. Patients with prior renal transplants, congenital pelvic kidneys, or horseshoe kidneys were included. Open repair was reserved for patients with no endovascular or hybrid repair options. Over an 8-year period, 18 patients were identified (renal transplant n=9, horseshoe kidney n=3, congenital pelvic kidney n=6). All transplant patients were treated with endovascular repair. Four required cross-femoral bypasses, 1 for retrograde allograft perfusion after aorto-uni-iliac (AUI) procedure to the contralateral external iliac artery and 3 for contralateral limb perfusion after endograft extension into iliac artery ipsilateral to allograft. Three transplant patients required carotid access due to severe iliofemoral occlusive disease or allograft origin off the internal iliac artery. Two horseshoe kidney patients underwent open repair with direct reimplantation of accessory renal arteries, whereas 1 underwent endovascular repair with exclusion of an isthmus branch. Of the congenital single/pelvic kidney cohort, 2 underwent open repair with renal reimplantation, 2 underwent endovascular aneurysm repair, 1 was treated with AUI and cross-femoral bypass, and one was treated with a staged iliorenal bypass and subsequent fenestrated endovascular repair. Intravascular ultrasound was used to minimize contrast use in patients with chronic renal insufficiency (Cr>1.5mg/dL, n=6). Over a mean follow-up of 31months (range, 1-110), there were no aortic deaths or reintervention, no decline in renal function (measured by serum creatinine and glomerular filtration rate), and 100% patency of the preserved renal arteries. Atypical renal anatomy should not preclude repair of aortic aneurysms. Repair of such aneurysms is safe and achieves good long-term outcomes with the use of the described techniques.

Evaluation of the accuracy of renal depth estimation formulas in horseshoe kidney.

Estimation formulas are usually used to calculate renal depth when glomerular filtration rate (GFR) is measured by the Gates method. Horseshoe kidney (HSK) anatomical structure is different from the normal form of the kidney. The existing formulas are based on the normal form. It is unknown whether the existing formulas are valid in HSK patients. This study was performed to estimate the accuracy of the existing 6 renal depth estimation formulas in HSK.Renal depth and total thickness (T, cm) of the body at the level of the kidneys were measured by CT in 94 HSK patients. Their sex, age, height (H, cm), and weight (W, kg) were recorded. The existing 6 estimation formulas were used to obtain estimated renal depth. Correlation coefficients, Bland-Altman analysis, and paired t test were performed between estimated and the CT measured renal depth.Estimated renal depths were all lower than the CT measured renal depths and there was significant difference between estimated and CT measured renal depth. The CT measured renal depth and estimated renal depth derived from Ma GY formula correlated best (right: r = 0.80, P < .01; left: r = 0.77, P < .01). The renal depth derived from Tonnesen formula was significantly lower than the CT measured renal depth. The agreement between the estimated renal depth derived from Tonnesen formula and the CT measured renal depth was the worst, with the mean difference of (right: −3.11 ± 1.13 cm; left: −2.79 ± 1.07 cm). The agreement between the estimated renal depth derived from Li Q formula and Ma GY formula and the CT measured renal depth was the best, with the mean difference of right: −1.68 ± 1.09 cm; left: −1.32 ± 1.06 cm and right: −1.59 ± 1.01 cm; left: −1.59 ± 0.99 cm, respectively. But the greatest error of the difference between Li Q formula and Ma GY formula estimated depth and the CT measured depth was up to −4.83 cm, and the estimated deviation is unacceptable.All the existing formulas do not fully apply to HSK. To provide reliable and accurate estimates of renal depth, we should develop a new formula to estimate the renal depth in HSK patients.

IP045. Management of Abdominal Aortic Aneurysms With Atypical Renal Artery Anatomy

Renal artery anomalies occur at a rate of 1% to 2%, and with a growing number of renal transplants performed annually, we are more frequently faced with particular challenges to abdominal aortic aneurysm repair. We describe here adjuncts used to manage such anatomic variants. This is a retrospective review of a prospectively collected database of all abdominal aortic aneurysms repaired in a single academic vascular surgery practice. Patients with renal transplants, congenital single/pelvic kidneys arising from the distal abdominal aorta or iliac arteries, and horseshoe kidneys were included in the review. Over an 8-year period, 18 patients were identified (prior renal transplant, n = 9; horseshoe kidney, n = 3; congenital single/pelvic kidney, n = 6). All prior transplant patients were treated with endovascular repair, with four requiring aortouniiliac extension to the external iliac artery contralateral to the renal transplant for aneurysm exclusion (with retrograde flow via cross femoral bypass providing renal perfusion). Additionally, three transplant patients required carotid artery access for device deployment due to severe iliofemoral occlusive disease or origin of renal transplant off of the internal iliac artery. Two horseshoe kidney patients underwent open aneurysm repair with direct reimplantation of accessory renal arteries, while one underwent standard endovascular repair with exclusion of an isthmus branch. While there was no renal dysfunction noted, the patient did have a prolonged course of abdominal pain postoperatively due to infarct of the devascularized renal segment. Of the congenital single/pelvic kidney cohort, two underwent open repair with renal reimplantation, two underwent standard endovascular repair, one was treated with aortouniiliac and cross-femoral bypass, and one was treated in a staged fashion with initial ileorenal bypass and subsequent fenestrated endovascular repair. Intravascular ultrasound imaging was used to minimize contrast use in patients with chronic renal insufficiency (creatinine >1.2 mg/dL, n = 6). Over a mean follow-up of 41.7 months (range, 1-110 months), there were no aortic related deaths or reinterventions, no decline in renal function (measured by serum creatinine and glomerular filtration rate), and 100% patency of the preserved renal arteries. Atypical renal anatomy provides unique challenges to abdominal aortic aneurysm repair. The use of technical adjuncts can make repair of such aneurysms safe with good long-term outcomes that do not impair renal function.

Robot-Assisted Laparoscopic Pyeloplasty in a Pediatric Patient with Horseshoe Kidney: Surgical Technique and Review of the Literature

The aim of this study was to describe the technical aspects of a robotic pyeloplasty in pediatric patients with uretero-pelvic junction obstruction (UPJO) in horseshoe kidney (HSK) through the report of our recent case, and to outline the state of the art of minimally invasive pyeloplasty (MIP) with a systematic review of the literature. We describe all the steps of our surgery performed on an 11-year-old patient with left UPJO in HSK in detail. All the anatomic landmarks are clearly showed, with particular attention to trocar placement in a pediatric patient. A systematic review of the literature on the outcomes of MIP in HSK patients has been performed, including 16 articles. Our surgery was successful following a standardized approach. However, we recorded a rare complication, the herniation of a small portion of omentum through the 8 - mm defect used for the caudal robotic port. The evidence synthesis shows excellent postoperative outcomes for both laparoscopic and robot-assisted laparoscopic pyeloplasties in HSK patients. Probably, MIP should be preferred to the traditional open approach in these patients, when feasible. Transperitoneal robotic pyeloplasty is an excellent minimally invasive choice for the treatment of UPJO in HSK pediatric patients. The pediatric setting should prompt attention to every detail to avoid unfortunate complications.

Tailored minimally invasive management of complex calculi in horseshoe kidney.

Complex calculi in horseshoe kidney (HK) present a significant management challenge. Here, we report the clinical efficacy of extracorporeal shock wave lithotripsy (ESWL), minimally invasive percutaneous nephrolithotomy (MPCNL) and flexible ureteroscopy (FURS), combined with holmium laser lithotripsy, in the treatment of calculi in HK. From January 2005 to May 2014, 62 HK patients with renal calculi were reviewed in terms of medical history, treatment modality and therapeutic outcome in a single tertiary care hospital. Among the patients, 11 with a solitary stone ≤ 1.5 cm in diameter received ESWL, leading to overall stone-free rate of 72.7%; 18 with stone diameter ≤ 2-3 cm received retrograde flexible ureteroscopy, with a recorded mean digitized surface area (DSA) of 339.6 ± 103.9 mm2, mean operation time of 93.1 ± 11.5 minutes and overall stone-free rate of 88.9%; and 33 with staghorn or complex calculi (d ≥ 2 cm) had MPCNL or MPCNL-FURS, with a recorded mean DSA of 691.0 ± 329.9 vs. 802.9 ± 333.3 mm2, mean operation time of 106.4 ± 16.6 vs. 124.4 ± 15.1 min and overall stone-free rate of 89.5% vs. 92.9%. For complex calculi (d ≥ 2 cm), MPCNL combined with antegrade FURS was superior in terms of reducing number of tracts, controlling mean hemoglobin drop, but required longer operation time, comparing with MPCNL alone. As minimally invasive treatments, a combination of MPCNL and antegrade FURS provides a safe and effective modality in the management of staghorn or complex calculi (d ≥ 2 cm) in HK with significantly reduced blood loss comparing to MPCNL alone, and retrograde FURS alone is favorable for stones with a diameter ≤ 2-3 cm. ESWL is effective for viable small solitary stones (d ≤ 1.5 cm). Treatment modality should be tailored based on individual condition.

Outcome of ureteroscopy for stone disease in patients with horseshoe kidney: Review of world literature.

Introduction and Objectives:The management of urolithiasis in patients with horseshoe kidney (HSK) is difficult. Stone formation occurred in 1:5 patients with HSK due to impaired urinary drainage and infections. Percutaneous nephrolithotomy and shock wave lithotripsy can be technically challenging due to altered anatomy.Materials and Methods:We conducted a systematic review of the literature to look at the role of ureteroscopy for stone management in these patients. We searched MEDLINE, PubMed and the Cochrane Library from January 1990 to April 2013 for results of ureteroscopy and stone treatment in HSK patients. Inclusion criteria were all English language articles reporting on ureteroscopy in patients with HSK. Data were extracted on the outcomes and complications.Results:A total of 3 studies was identified during this period. Forty-one patients with HSK underwent flexible ureteroscopy and stone treatment. The mean age was 42 with a male:female ratio nearly 3:1. The mean stone size was 16 mm (range: 3-35 mm). The mean operating time was 86 min with multiple stones seen in 15 patients. All 41 patients had a ureteral access sheath used and flexible ureteroscopy and holmium laser fragmentation done. Thirty-two (78%) patients were stone-free with a mean hospital stay of 1-day. Minor complications (Clavien I or II) were seen in 13 (32%) of which 6 had stent discomfort, 3 needed intravenous antibiotics for <24 h, 3 had hematuria of which 2 needed blood transfusion and one had pyelonephritis needing re-admission and antibiotics. There were no major complications found in the review.Conclusions:Retrograde stone treatment using ureteroscopy and lasertripsy in HSK patients can be performed with good stone clearance rate, but with a slightly higher complication rate. This procedure should, therefore, be done in high volume stone center with an experienced stone surgeon/team.

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

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. 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. 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. 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.