|Year : 2014 | Volume
| Issue : 5 | Page : 645-647
Variation of hilar anatomy in an incompletely rotated kidney associated with accessory renal vessels
Smita Singh Banerjee, Vaishali Paranjape, Vasanti Arole, P Vatsalaswamy
Department of Anatomy, Padmashree Dr. D. Y. Patil Medical College, Hospital and Researh Centre, Dr. D. Y. Patil Vidyapeeth, Pune, Maharashtra, India
|Date of Web Publication||10-Sep-2014|
B3, 4 Sarita Society, Near Karve Statue, Kothrud, Pune - 411 038, Maharashtra
Source of Support: None, Conflict of Interest: None
An incompletely rotated left kidney, with variations in the hilar anatomy associated with accessory renal vessels was seen during routine undergraduate dissection in an adult male cadaver. The left kidney showed three accessory renal vessels. Two renal arteries and one vein entered the lower pole of left kidney. The hilum of the kidney was anteriorly faced and was close to the upper pole, with the ureter running on the anterior surface of the kidney. This was associated with variation in the arrangement of the structures at the hilum. Structures found at the hilum from superficial to deep were: The ureter, one renal vein, and two renal arteries. The ureter was anteroinferior and lateral to the renal vein. The renal arteries were posterosuperior and posteroinferior to the renal vein. The rotational anomaly associated with the presence of accessory renal vessels assumes importance while performing percutaneous procedures in relation to the kidney, screening of donors, and also during interpretation of various radiological diagnostic procedures related to the kidney.
Keywords: Accessory renal vessels, incompletely rotated kidney, polar artery, renal hilar anatomy
|How to cite this article:|
Banerjee SS, Paranjape V, Arole V, Vatsalaswamy P. Variation of hilar anatomy in an incompletely rotated kidney associated with accessory renal vessels. Med J DY Patil Univ 2014;7:645-7
|How to cite this URL:|
Banerjee SS, Paranjape V, Arole V, Vatsalaswamy P. Variation of hilar anatomy in an incompletely rotated kidney associated with accessory renal vessels. Med J DY Patil Univ [serial online] 2014 [cited 2021 Apr 20];7:645-7. Available from: https://www.mjdrdypu.org/text.asp?2014/7/5/645/140479
| Introduction|| |
The right kidney lies at a slightly lower level than the left one, so the transpyloric plane passes through the upper part of the hilum of the right kidney and lower part of the hilum of the left kidney. The hilus of both kidneys face medially. At the hilum, the renal vein is seen anterior and the pelvis of the ureter is seen posterior to the renal artery. The left and right renal arteries arise from the lateral aspect of the abdominal aorta just below the origin of the superior mesenteric artery, at the level of the L1 vertebra. The right renal artery is longer and higher than the left. The renal artery and its branches lie between the renal vein and the pelvis of the ureter.  Each renal artery divides into an anterior and a posterior division. The branches from the anterior division supply the apical, upper, middle, and lower segments. The posterior division supplies the posterior segment of the kidney. These five segments are always present and there is no collateral circulation between these segments.  Knowledge of the presence of an extra renal vessel and variation in the hilar structures is essential while performing various surgical, invasive, and renal transplant procedures, and also during interpretation of various radiological techniques related to the kidney.
| Case Report|| |
Multiple variations were noted in the left kidney of an adult male cadaver. The hilum of the kidney was anteriorly faced and was closer to the upper pole. The variations in the structures seen at the hilum were as follows: The pelvis of the ureter was placed lateral and inferior to the renal vein. Out of the two branches of the renal artery entering the hilum, one branch entered above and the other branch entered below the renal vein, at the hilum of the left kidney. The ureter further descended on to the anterior surface of the kidney [Figure 1]. Two accessory renal arteries, accompanied by one vein entered the lower pole of the same kidney. Both the accessory renal arteries were branches from the abdominal aorta. The accessory renal vein was inferior to the accessory renal arteries and passed posterior to the common iliac arteries. It drained into the left common iliac vein [Figure 2].
|Figure 1: (a) Anteriorly placed hilum; (b) Ureter anteroinferior to renal vessels; (c and d) Accessory renal arteries of lower pole; (e) Accessory renal vein; (f) Inferior mesentric artery; (g) Abdominal Aorta; (h) Left Renal Vein|
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|Figure 2: (a) Accessory Renal vein; (b and c) Accessory Renal arteries; (d) Inferior Mesenteric artery; (e) Abdominal Aorta; (f) Inferior Vena Cava; (g) Left Renal Vein; (h) Left Renal Artery|
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| Discussion|| |
An artery arising from the aorta in addition to the main renal artery is called an accessory renal artery. An artery arising from sources other than the aorta is called as an aberrant renal artery.  The incidence of vascular anomalies related to the renal artery is around 30%.  However, the coexistence of multiple vessels and variation in the hilar anatomy, in a partially rotated kidney is a phenomenon for discussion.
Most of the abnormalities of the renal artery are due to the changing position of the kidney, as a part of its normal development and ascent. Kidneys develop from the intermediate mesoderm in the pelvic region. Later they ascend to the lumbar region, which is their adult position. In the pelvic region they are supplied by branches of the internal iliac artery or common iliac artery. Even as the kidney ascends to the lumbar region, its arterial supply also shifts from the common iliac to the abdominal aorta successively. Felix has divided nine pairs of lateral mesonephric arteries in an 18 mm fetus in the cranial, middle, and caudal groups. The middle group constitutes the third, fourth, and fifth pairs. This middle group later on remains as renal arteries, and the persistence of more than one artery from the middle group leads to the occurrence of an accessory renal artery.  The presence of an accessory/aberrant/abnormal renal artery at the lower pole is in fact a segmental vessel that is a persistent fetal vessel, with an abnormal origin. 
The occurrence of lower polar arteries found in three different studies was 10.8, 3, and 5.3%, respectively. ,,
Two renal arteries were seen on the right side in addition to the normal renal artery. The cranially placed artery entered the anterior aspect of the kidney 4 cm below the upper pole, while the caudally placed artery entered the lower pole as reported by Neelesh Kanaskar et al. 
Abt et al.  reported a case of a 37-year-old man suffering from type 1 neurofibromatosis. His angiography revealed two renal arteries, one normal and one inferior polar, with aneurysmal alteration. The patient suffered a further spontaneous rupture of the polar as well as the right main renal artery, and nephrectomy became unavoidable.
This wide difference in the incidence of lower polar arteries and the complications associated with it definitely warrant awareness of its existence and meticulous dissection of the lower pole while mobilizing the kidney.
Pollack H and McClennan B L  are of the opinion that renal rotation takes place before definitive vascularization. This process occurs between 38 and 49 days of development, during the ascent of the kidney. The developing metanephros rotates from the dorsomedial to a more lateral position, relative to the collecting system, resulting in the hilum of kidney eventually rotating from the anterior to the medial position. In non-rotation, the renal pelvis presents itself ventrally in relation to the kidney mass. In incomplete rotation it presents itself ventromedially. The renal pelvis is seen anteriorly in our case.
However, according to Bauer SB  the ureteral branching induces differentiation of the metanephric tissue, different degrees of unequal branching result in various forms of malrotation. The rotation has been postulated to be a consequence of unequal branching of successive orders of ureteral trees. With excessive ventral branching more parenchyma develops ventrally and the renal pelvis seems to rotate medially. In our case, probably the ureteral tree branched less on the ventral aspect, thereby leading to incomplete rotation, and so the hilum was faced anteriorly.
Ruta N Ramteerthankar et al.  found bilateral unrotation of the kidneys in a female cadaver, without any associated variation. Ingole I.V. Ghosh S. K  reported a case of a right laterally rotated kidney detected by intravenous pyelography in a female patient investigated for urinary symptoms. Wai-Yan Wong et al.  reported admitting a patient for further investigation after a suspected hyperechoic lesion was seen in the middle pole of the right kidney on renosonography. Angiography confirmed that the hyperechoic lesion was of the right renal artery, present ventral to Inferior Vena Cava and entered laterally, facing the right renal hilum.
Varieties of anomalies have been documented in literature so far. Availability of a huge amount of data about the presence of multiple renal arteries, categorized as accessory, aberrant, additional or extra renal arteries, unilaterally or bilaterally, superior and inferior polar arteries, necessarily points toward the need for a uniform and internationally acceptable nomenclature and classification of renal arteries. Coexistence of multiple variations, as seen in our case, is rare, hence, it assumes great importance and needs to be documented, as use of kidneys with multiple renal arteries from live donors will require a longer common aortic cuff from the donor and difficulty may arise in achieving multiple arterial anastomoses in the recipient. This can result in a prolonged time of ischemia, poorly controlled hypertension, and sometimes graft rejection. Knowledge of the renal vascular anatomy is important to the nephrologists while performing percutaneous nephrostomy, renal biopsy, and to the surgeons while dealing with retroperitoneal tumors.
Meticulous screening of donors and urological patients is a must to rule out variations in the vascular anatomy of the kidney, and it becomes mandatory in order to avoid intraoperative and postoperative complications.
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[Figure 1], [Figure 2]