Minimally Invasive Approaches for Stone Clearance in Crossed Fused Renal Ectopia

Abstract

Crossed fused renal ectopia (CFRE) is a rare fusion anomaly of the kidneys, with a predisposition to calculus disease. Management of renal calculi in CFRE is not standardized because of paucity of literature. We managed a 32-year-old man with left to right CFRE with multiple stones in both the kidneys by percutaneous nephrolithotomy for the right moiety and laparoscopic pyelolithotomy for the crossed moiety. Based on the stone burden and anatomy, we decided to go for a staged approach, to provide maximum clearance rate with least risk. We share our experience in this case, with regard to the use of two different but minimally invasive modalities for effective management of the patient. We also emphasize on the utilization of a staged approach whenever required for patient safety. We also reviewed the literature regarding the management of kidney stones in this rare anomaly.

Introduction

Crossed fused renal ectopia (CFRE) is an unusual congenital malformation of the urinary tract. In this condition, both kidneys are located on one side of the midline and are fused with each other. Management of renal stone in CFRE is difficult because of abnormal location, malrotation, and its varying relations with vertebral column and abdominal viscera. Because of the lack of standardized management protocol for calculus disease in CFRE, these patients are usually managed based on the clinical judgment and experience. We came across a young man with crossed fused left to right ectopia with multiple calculi in both the kidneys. Patient was managed by right mini percutaneous nephrolithotomy (PCNL), followed by transperitoneal laparoscopic pyelolithotomy of the left moiety, 3 weeks later.

Case Report

A 32-year male patient presented to QRG Hospital, Faridabad, India, with complaint of pain in right flank off and on for 6 weeks. Contrast-enhanced CT abdomen was done, which showed left kidney lying inferior to and fused with the right kidney. Multiple calculi were found in the right kidney, largest measuring 14 × 10 mm in renal pelvis (Figs. 1 and 2). The left moiety was having a 20 mm calculus in pelvis and another 8 mm calculus at upper pole. There was normal contrast excretion from both kidneys. Right ureter was seen coursing lateral to the left kidney and draining through right vesicoureteric junction (VUJ) to the bladder. Left ureter was crossing the midline and draining into the bladder through left VUJ. Blood investigations were within normal limits, and the urine culture was sterile.

FIG. 1.

Reconstructed CT image in coronal section showing left to right crossed fused renal ectopia with calculi in upper moiety.

FIG. 2.

Reconstructed CT image in sagittal section showing left to right crossed fused renal ectopia with calculi in both moieties and relation of kidneys to nearby structures.

Patient was explained about his condition, the need for surgery and the possible treatment option in this particular clinical scenario. It was decided to manage right moiety by mini PCNL with Double-J stent placement in the left moiety followed by laparoscopic pyelolithotomy of the left moiety after 3 weeks. After taking well-informed written consent from patient and complete preanesthetic checkup, patient was posted for the surgery.

Under general anesthesia, cystoscopy was done and Double-J stent placed into left ureter and 5F ureteral catheter into the right ureter. Mini PCNL was performed on the right moiety in prone position with the standard technique (Fig. 3), making three separate punctures and tract dilatation upto 16F. Procedure was uneventful and nephrostomy tubes were removed on postoperative day 1. Patient was discharged on postoperative day 2. Postoperative X-ray showing complete clearance in right moiety (Fig. 4).

FIG. 3.

Fluoroscopy image of puncture and guidewire passage for PCNL in upper moiety. PCNL, percutaneous nephrolithotomy.

FIG. 4.

Post-mini PCNL X-ray image showing complete stone clearance in right kidney.

After 3 weeks, patient was readmitted, preanesthetic review was done and posted for transperitoneal laparoscopic pyelolithotomy of left moiety under general anesthesia. Laparoscopy was undertaken by placing a 12 mm camera port at umbilicus and two pararectal ports about 5 cm away from umbilical port, one in right iliac fossa and another in right hypochondrium, in a triangular manner. Right colon was reflected to reach the renal pelvis, which was facing anteriorly. After dissection, pyelotomy was made by using monopolar hook cautery. Both the calculi were removed intact (Fig. 5). Double-J stent was placed before closing the pyelotomy. Pyelotomy incision was closed with continuous 4-0 Vicryl round body suture. A 14F abdominal drain was left through 5 mm lower abdominal port. Procedure was uneventful. Abdominal drain was removed on postoperative day 2. Patient was discharged on postoperative day 3, after removing urethral catheter.

FIG. 5.

Calculi removed from lower moiety by laparoscopic pyelolithotomy.

Discussion

CFRE is the second most common renal fusion anomaly after horseshoe kidney.¹ Abnormal anatomical orientation and location predisposes these kidneys to calculi formation and makes them a difficult entity to treat. Various modalities of treatment were tried in the past with variable success rates. Open stone removal, extracorporeal shockwave lithotripsy (SWL), PCNL, retrograde intrarenal surgery (RIRS), and laparoscopy have all been used based on the clinical scenario. Main challenge in our case was to find a management plan that can be maximally effective yet minimally invasive.

Stone burden and anatomy rules out SWL as a management option in this case. SWL is usually technically difficult in such cases because of underlying bone and overlying bowel gases. Clearance of stone may also be suboptimal after fragmentation because of malrotation.

There are reports of PCNL in CFRE by Rana and Bhojwani²; and Gupta et al.,³ but a mention of the side of PCNL and the type of CFRE is lacking in their reports. In our experience, the orthotopic right moiety in the left to right CFRE behaves just like a normal kidney and can be easily managed by standard PCNL technique.

Flexible ureterorenoscopy is a safe option for the treatment of renal stones in anomalous kidneys with satisfactory success rates.⁴ Huang et al.⁵ used flexible ureterorenoscopy to remove calculi in a patient with a twisted ureter crossing the midline. We also had the option of RIRS in this case. But because of large stone burden in both the moieties, it was not utilized.

Laparoscopic pyelolithotomy is also described as a useful modality for stone removal in CFRE.⁶ Transperitoneal and retroperitoneoscopic approaches have been used for various indications. We used the transperitoneal approach in our patient. Anteriorly facing renal pelvis made the identification and dissection easier. We were able to provide complete stone clearance.

In view of high stone burden and calculi located different calices, RIRS or laparoscopic pyelolithotomy were not the ideal treatment option. So we decided to go for mini PCNL for the upper renal moiety Because of more medial location of the lower moiety, PCNL was technically challenging and risky. So it was decided to go for staged management. The lower moiety stones, and residual upper moiety stones, if any, were planned, to be managed by laparoscopic pyelolithotomy after at least 3 weeks of the first procedure.

Conclusion

Calculus disease in CFRE affecting both the moieties can be well managed by following a staged approach, using mini PCNL for the orthotopic moiety and laparoscopy for ectopic moiety, to provide maximal clearance with least risk.

Abbreviations Used

CFRE

cross fused renal ectopia

CT

computed tomography

PCNL

percutaneous nephrolithotomy

RIRS

retrograde intrarenal surgery

VUJ

vesicoureteric junction

Disclosure Statement

No competing financial interests exist.

Funding Information

This study is self-financed.

Cite this article as: Bhatnagar A, Choudhary MK, Kumar S (2020) Minimally invasive approaches for stone clearance in crossed fused renal ectopia, Journal of Endourology Case Reports 6:4, 374–376, DOI: 10.1089/cren.2020.0119.