|Year : 2014 | Volume
| Issue : 3 | Page : 121-123
Inhabitation of an accessory renal artery in a cratered hilum of a malrotated kidney
Naveen Kumar, Anitha Guru, Jyothsna Patil, Deepthinath Reghunathan, Sudarshan Surendran, Satheesha Nayak Badagabettu, Abhinitha Padavinangadi
Department of Anatomy, Melaka Manipal Medical College (Manipal Campus), Manipal University, Manipal, Karnataka, India
|Date of Web Publication||6-Sep-2014|
Department of Anatomy, Melaka Manipal Medical College (Manipal Campus), Manipal University, Manipal 576 104, Karnataka
Source of Support: None, Conflict of Interest: None
Structural variations of the kidney and its abnormal vascular architecture make the kidney unsuitable for transplantation. We report here a case of malrotated left kidney with cratered hilum and presence of an accessory renal artery. A lumbar vein was seen to loop under the accessory renal artery on the way of its termination into the left renal vein. The kidney appeared to have failed to rotate from its fetal position. Thus, the hilum was placed ventrally. The hilum was crater-like in shape, wide, and allowed passage of the hilar structures. The shape of the kidney itself had undergone slight modification as it appeared more ovoid than its typical bean shape. The poles, but not the surface or borders were distinguishable. The variations described in the current observation are of a unique pattern of congenital malformation having surgical, urological, and radiological implications.
Keywords: Accessory renal artery, hilum, kidney, lumbar vein, malformation
|How to cite this article:|
Kumar N, Guru A, Patil J, Reghunathan D, Surendran S, Badagabettu SN, Padavinangadi A. Inhabitation of an accessory renal artery in a cratered hilum of a malrotated kidney. Sahel Med J 2014;17:121-3
|How to cite this URL:|
Kumar N, Guru A, Patil J, Reghunathan D, Surendran S, Badagabettu SN, Padavinangadi A. Inhabitation of an accessory renal artery in a cratered hilum of a malrotated kidney. Sahel Med J [serial online] 2014 [cited 2023 Mar 21];17:121-3. Available from: https://www.smjonline.org/text.asp?2014/17/3/121/140298
| Introduction|| |
The kidneys are retroperitoneal organs, situated in the posterior abdominal wall, on both sides of the vertebral column. Each kidney presents a hilum on its medial border for the passage of structures to and from it.  In the early stages of development, the hilum faces ventrally and later rotates along its vertical axis such that the hilum is present on the medial border. Throughout development, there is change in position and location of kidney. Thus, the kidney receives blood supply from the vessels closest to it throughout its ascent from the pelvis to the abdomen. Failure of involution of such arteries results in the presence of accessory renal arteries. 
Variations in the course and drainage of the first lumbar vein are fairly well known. It often joins the second lumbar vein or either drains into ascending lumbar vein or into lumbar azygos vein.  Variations in the renal vasculature are also common. We report here a case of variation involving a malrotated left kidney with an unusually shaped hilum facing ventrally and presence of an accessory renal artery below, which is the looping of the lumbar vein.
| Case report|| |
During routine dissection of a male cadaver aged about 60 years of South Indian origin, we observed multiple variations pertaining to the left kidney. The left kidney appeared to be malrotated such that the hilum of the kidney was facing anteriorly and the anterior surface was facing laterally. The left renal artery with a normal course was observed to be slightly tortuous and was accompanied by an accessory renal artery [Figure 1]. The accessory renal artery took origin from the abdominal aorta about 2 cm below the origin of main renal artery and entered the hilum of the kidney near its lower margin. An unusual pattern of looping of a lumbar vein was also noted at the proximal end of the accessory renal artery [Figure 1]. The lumbar vein, presumably the first one owing to its location, was seen passing under the accessory renal artery and then back upward and draining into the left renal vein, unlike its usual course.
The shape of the kidney too appeared altered. The kidney appeared more ovoid in contrast to its normal bean shape. The poles were distinct but, the surfaces and borders were undistinguishable. The hilum presented an unusual cratered feature that was observed to be remarkably large [Figure 2].
|Figure 1: Showing the origin of main renal artery (MRA) and accessory renal artery (ARA) from abdominal aorta (AA) looped by left lumbar vein (LV). RRA: Right renal artery; LRV: Left renal vein; IVC: Inferior vena cava; IMA: Inferior mesenteric artery; LK: Left kidney; LTV: Left testicular vessels|
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|Figure 2: Closer view of main renal artery (MRA) and accessory renal artery (ARA) at cratered hilum (H) of left kidney (LK). RRA: Right renal artery; AA: Abdominal aorta; IVC: Inferior vena cava; IMA: Inferior mesenteric artery; LU: Left ureter; LRV: Left renal vein; LTV: Left testicular vessels; RP: Renal pelvis|
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| Discussion|| |
An accessory renal artery is the precocious origin of a segmental artery.  As early as in 1883, Macalister provided a primitive classification of multiple renal arteries as belonging to three categories: (1) those that emerge from aorta, (2) those that emerge from other sources, and (3) those that emerge from both.  Virendra et al.,  in their extensive cadaveric study in the North Indian population, have tabulated the number, percentage, and types of supernumerary renal arteries.  In a study done by Elizabeth et al. on potential kidney donors, accessory renal arteries were found in 29% of left kidneys.  Accessory renal arteries are typically equal in size to the single renal artery,  which was as observed in the present case. The major importance of the present case report is the looping of first lumbar vein and the presence of displaced hilum. To the best of our knowledge, there has been no explanation of looping of the first lumbar vein underneath the accessory renal artery. Nonetheless, a similar pattern of drainage has been reported by Syed et al.,  where the first and third left lumbar veins were observed to be draining into the left renal vein. 
The uniqueness of the present case report is the shape and orientation of the hilum of the kidney. The observed change in orientation of the kidney may be attributed to embryological factors. Jacob describes in his study a case of malformed and malrotated kidneys.  Kidney, after its ascent to its adult anatomical position, fails to rotate along its vertical axis such that the renal hilum is positioned along the medial border and faces medially.  Thus, in this reported case, the kidney has failed to rotate along its vertical axis and continues to remain in the fetal position. The ventrally placed hilum is shaped like a crater, wide enough to allow easy passage to the hilar structures.
El Fettouh et al. reported that during clinical procedures like removal of donor kidney, renal vessels need close attention because variant vascular pattern may result in its damage and subsequent ischemic complications.  In selective angiography, the radiologists must be aware of unusual origins of renal vessels to insert catheter into the correct vessel, which is very important for the accuracy of diagnosis. 
Urological surgery demands a sound knowledge of renal hilar structures.
The variations described in the present case are a unique pattern of congenital malformation. The variant vascular architecture, as reported herein, may be the potential cause for iatrogenic damage during surgical and radiological approaches. Further, structural variations of the kidney and its abnormal vascular architecture make the kidney unsuitable for transplantation.
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[Figure 1], [Figure 2]