Renal pelvis stone in reverse kidney: A case report and literature review.

In neonates, kidney and urinary tract anomalies, like rotation anomalies, may be observed at rates of 3-11%. During rise to the lumbar region, the kidney completes rotation from left to right around the long axis from top to bottom and the renal hilum turns toward the medial direction. However, generally due to vascular causes, this rotation around the long axis of the kidney (renal axis, pole to pole) may be incomplete or may not occur. In this case report, we present a 45-year old male patient with stone in a kidney with renal hilum facing fully lateral.

Introduction

Urinary tract anomalies may be observed in 3–11% of neonates. The main renal anomalies may be listed as renal hypogenesis, horseshoe kidney, ectopic kidney, cross fusion ectopy, duplicated ureter, malformations in pelvicalyceal structure and renal rotation anomalies. Renal malrotations are rare entities with variation in the kidney and hilum positions, more common in males and identified at rates of 1/2000 in autopsy studies. Rotation anomalies are generally unilateral and these people generally remain asymptomatic throughout their lives without urinary system obstruction.

In the embryologic period the kidney is sourced in metanephros in the sacral region and reaches the lumbar region at the end of the 7th week intrauterine. During this elevation, rotation is completed and the renal hilum remains medial. Rotation anomalies are described according to the status of the renal hilum when rotation completes. There may be rotation anomalies without elevation with the renal hilum generally facing ventral in anomalies like ectopic kidney.

Case report

A 45-year old male patient attended our clinic with right flank pain and back pain. Imaging methods like radiography, urinary system USG and noncontrast computerized tomography (NCCT), serum creatinine, CRP, WBC, urine analysis and urine culture tests were performed.

Serum creatinine (0.85 mg/dL), WBC (9.84 10∧3/mm3) and CRP (4 mg/L), urine analysis (normal) and urine culture/antibiogram (no proliferation of pathogenic bacterial agents) were performed. Imaging showed bilateral kidneys in the normal lumbar region. Axial-coronal and sagittal cross-section NCCT found the right kidney renal hilum was facing lateral, with renal parenchyma convex ridge facing medial toward the vertebral column. Axial, sagittal and coronal NCCT sections found the kidney was reversed around the long axis with 270-degree rotation (Fig. 1, Fig. 2). Based on these findings, we determined the patient's right kidney was a reverse kidney.

Fig. 1

Axial non-contrast CT section.

White arrow points to the lateral renal pelvis filled with stones.

Fig. 2

Coronal non-contrast CT Section

White arrow points to the renal pelvis filled with stones laterally facing.

The renal pelvis and lower calyx contained stone load with 45 × 32 mm diameter. There were multiple stones in the lower calyx. Thus, we planned surgery for the patient due to high stone load. Initially we considered PCNL, with entry through the lower or upper pole calyces. As we could not obtain appropriate access for PCNL, we performed open pyelolithotomy with a subcostal retroperitoneal incision by turning the patient to lateral decubitus position. After surgery, the patient was fully stone-free and was discharged on the 4th day postoperative.

Discussion

With estimated congenital renal and urinary malformations (renal ectopy, cross fusion ectopy, horse shoe, complete ureter, pelvicalyceal system differences, rotation anomalies) present in 3–11% of neonates, the true incidence is unknown. Generally they are discovered incidentally because most of the entities remain asymptomatic. However, urinary stasis, urinary infection and kidney stone-hydro/pyonephrosis cases may occur more frequently due to opening-spreading of these malformations in the renal pelvic output (ureteropelvic junction)than in kidneys with normal anatomy.

Rotation anomalies of the kidneys are generally accompanied by accessory renal veins, with these aberrant veins the cause of many rotation malformations. Bilateral cadaver dissections and preoperative contrast computerized tomography report malrotated kidneys are frequently accompanied by aberrant veins., Patients with malformed kidneys requiring surgical intervention should have the renal axis carefully observed on preoperative imaging, and the neighboring organ localization and aberrant vein structures fully revealed. For each patient with these malformations, including rotation anomalies, the same surgical method may not be appropriate, with the decision about surgical method made individually.,

In this case as we did not have contrast computerized tomography to reveal the renal vascular structure we did not know the numbers of renal veins and arteries. However, we observed the renal vascular structures remained medial on NCCT.

Different renal rotation anomalies have been reported. These include A. nonrotation and incomplete rotation, ventral of the renal pelvis, convex ridge of the kidney dorsal (most frequently observed); B. hyperrotation-excessive rotation with the hilum posterior, convex renal ridge ventral; and C. rarer reverse rotation with excessive rotation (as in our case) localized according to the degree of renal pelvis rotation. In our case there was 270-degree rotation facing fully lateral, with the convex ridge of the kidney fully medial parallel to the vertebra extending from top to bottom from upper pole to lower pole.

We encountered a few articles about rotation anomalies in the literature, but nearly all were patients with incomplete or nonrotatedecotopic kidneys. The most similar to our patient was a reverse kidney without stones with incidental diagnosis by Di Guilliano et al. But though we screened the literature in detail, we did not find any article about a fully reverse kidney anomaly patient with intense stone load like our patient. We think this is the first case report in the literature about reverse stone kidney and treatment.

PCNL is most commonly used for kidney stone surgery currently but we could not gain access, so for this reverse rotation anomaly we were forced to perform open pyelolithotomy or laparoscopy pyelolithomy (retroperitoneal). Though lower morbidity, we chose the open surgery methoddue to not having experience of retroperitoneal laparoscopic surgery. In our clinic stone treatment methods like PCNL, RIRS and ESWL are commonly used with transperitoneal laparoscopic pelviureterolithotomy performed less frequently. We have not performed open pyelolithotomy for many years in our clinic, but this case reminds us that open surgery still has a place for some cases. In conclusion, kidney rotation anomalies are rarely observed renal entities with frequent association with aberrant veins and good preoperative imaging is a condition for selection of appropriate surgical method and access.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors.

Informed consent and patient details

Informed consent and patient details were obtained from the patient by the author.

Declaration of competing interest

None.