DOUBLE RENAL ARTERY IN HUMAN CADAVERS : A CASE REPORT

Two renal arteries supply the human kidneys: one to the right kidney and another to the left kidney, both branches of the abdominal aortic. Renal artery duplication is an anatomical variation, which is a normal flexibility of the topography and morphology in body structures. Functionally, it does not impair the body, as the blood supply is vital to tissue survival. In this context, the case study has great importance, once knowing the variations of the renal vessels assist when structuring surgeries and radiological studies in humans. Variations in vascular anatomy are often found in humans. Several authors characterize it: the prevalence of multiple vessels occurs in approximately 20-50% of cases. This is an observational study; we aimed to describe the anatomical variations concerning the duplicity of the renal artery in human cadavers, focusing on possible implications to clinical and surgical procedures. We dissected and analyzed four urinary block systems in adult cadavers, male, with focus on the vascularization. In these, two right kidneys present double renal arteries. Thus, we can infer that this knowledge can be used to improve surgical interventions, such as transplants.


INTRODUCTION
The human kidney is a paired organ located posterior to the visceral peritoneum.At its medial edge, there is a vertical fissure called the renal hilum, composed by ureter, renal artery and vein, constituting the renal pedicles (FERREIRA et al., 2014;DIÉGUEZ et al., 2016).
Bredel performed the first anatomical studies on renal vascular segmentation in 1901, confirming the findings from Hyrtl, in 1882.The first study of renal vascularization was conducted by Fue Berenger (1470-1530), and the acknowledgment of this anatomical data was credited to John Honter, in 1794 (SKANDALAKIS; McCLUSKY, 2006).These findings are of fundamental importance in the anatomical-clinical understanding of the anatomical variations of the urinary system.
According to the anatomical descriptions, each kidney is supplied by a single renal artery, originated in the abdominal aorta, between the 1st and 2nd lumbar levels (OZKAN et al., 2006).Renal artery duplicity can be defined as of normal flexibility in its topography and morphology, with no apparent functional changes (SANUDO; VAZQUEZ;PUERTA, 2003).This variation is, presumably, clinically silent, only being discovered when surgical procedures are needed, by imaging procedures and/or autopsy.
Variations in vascular anatomy are often found in men and are characterized by several authors: the prevalence of multiple vessels occurs in 20-50% of cases (BORDEI; SAPTE; ILIESCU, 2004).However, some cases of renal artery variations are rare, as described by Isoda et al., (2002), where a supplementary artery from an opposing renal artery crosses the aorta with direction to the contralateral kidney.On that note, this case study presents big importance, because this information about the renal vessels variations helps structuring surgical and radiological studies (SEBBEN et al., 2010;DIÉGUEZ et al., 2016).
The literature consulted reports that this knowledge is important in treatments and research of various diseases, such as: renal trauma, renal vascular hypertension, embolization of renal artery, and surgical methods such as: angioplasty or vascular reconstruction for congenital and acquired lesions, aneurysm, abdominal aortic surgery, conservative renal surgery or radical and kidney transplantation (PEREIRA-CORREIA et.al., 2009).Due to the wide range of morphological and numerical variations present in the renal hilum; to the constant development of imaging techniques and transplantation, the interest of anatomists in such studies have been increasing (KUMAR, 2012).

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These numerical variations, concerning the origin of the renal arteries in humans, are also important to kidney transplants and other diseases, as they can be compared to the normal morphology.In surgical and radiological procedures, the anatomical description of the renal vasculature is necessary to avoid errors concerning these variations (KHAMANARONG et al., 2004;MARTINEZ-MIER, et al., 2012).
We aimed to report two cases of renal artery duplicity in human cadavers, focusing on clinical and surgical implications.

CASE REPORT
To the present study, we used 04 urinary block systems, removed from adult human cadavers, from the collection of the Human and Comparative Anatomy Laboratory, of the Federal University of Goiás -Jataí.They were fixed and preserved in glycerin.We dissected the renal blocks, which had already been removed from the cadavers, and identified both the renal hilum (an oval area in the middle of the medial border, where the renal artery arrives) and the renal vein (where lymphatic vessel and ureter arise).The renal arteries are branches of the abdominal aorta, allowing its partial removal.We measured the length, width and thickness of the kidneys and the length of the double arteries, from the abdominal aorta to the renal hilum, using precision calipers.We photographed the structures with the camera Canon Power-Shot SX270 HS.
We observed the presence of double renal artery in two right kidneys (Figures 1A and 1B).The dimensions of the right kidney on the first urine block were 9.4 cm long, 5.9 cm wide, 2.9 cm thick, and the length of the arteries were 4.1 cm.For the second block, the dimensions of the right kidney were 10.6 cm long, 5.0 cm wide, 3.2 cm thick, and the length of the arteries measuring 5.7 cm.

DISCUSSION
An anatomical variation is defined by any difference in the morphology of human or animal body, without impairing the function, unlike malformations, which causes significant physiological damage, sometimes incompatible to life (SANUDO; VAZQUEZ; PUERTA, 2003).Moreover, anatomical variations may be related to predispositions of certain illnesses, found in clinical examination (BORDEI; SAPTE; ILIESCU, 2004).
The adult human kidney is around 11 to 13 cm long, 3 cm thick and 5 cm wide.It occupies, longitudinally, the space between the 12th thoracic and the 3rd lumbar vertebrae.The right kidney is positioned nearly 1.5 cm lower than the left, due to the presence of the liver.The left kidney is slightly longer, thinner and closer to the median plane, compared to the right kidney.(NETO; BRITO;2001;ROA;BARRAGÁN, 2011).The dimensions we observed corroborates these morphological patterns: the right kidney from the first block was 9.4 cm long, 5.9 cm wide and 2.9 cm thick; the right kidney from the second block was 10.6 cm long, 5.0 cm wide and 3.2 cm thick.The length of the double renal arteries was measured from the abdominal aorta to the renal hilum.The right renal artery, from the first block, was 4.1 cm long; the one from the second block was 5.7 cm long.When the renal artery morphometry was analyzed, Diéguez et al. (2016) found that the right renal artery presented a greater length, with a mean of 3.4 ± 0.9 cm, while the left renal artery had a mean of 2.8 ± 0.9 cm.This morphometric data does not refer to anatomical variation, such as duplicity, only to the morphometry.To them, the morphometric parameters are of vital importance in the effective planning process of a kidney transplant surgery.
Complex renal vascularization remains a problem that can affect the prognosis of transplantation, increasing vascular complications.The various challenges in kidney transplant surgery result of anatomical variations, such as multiple renal arteries, which occur in 12-30% of the kidneys that were transplanted and observed by Martinez-Mier et al. 2012.The presence of renal double artery was investigated before in a study about renovascular hypertension, to see if its prevalence causes complications in patients (EBRI et al., 1990).
Some methods such as renal angiography can be obtained through multidetector computed tomography (MDCT), which is now considered a non-invasive, fast and very important tool in the study of vascular anatomy and its variations, such as renal artery duplicity.This method is basic to presurgical evaluations, mainly in interventions such as partial nephrectomy, laparoscopy and renal transplantation (STOISA et al., 2009).
Another common variant is the pre-hilar arterial bifurcation, which has fundamental importance in renal donor patients because, for a surgical procedure, a minimum length of 2cm in the main renal artery is necessary before the bifurcation, to guarantee an adequate anastomosis.As previously described, anatomical variations of renal arteries are important in the preoperative assessment of patients undergoing nephrectomy for kidney donation, the technique of choice is laparoscopy and the risk of hemorrhage from vascular injury can be substantially reduced if there is prior knowledge about the preoperative radiological evaluation of renal angiography of the donor using non-invasive and effective multidetector computed tomography in the diagnosis (BORDEI; APTE; ILIESCU, 2004;STOISA et al., 2009).In addition, the angiotomography technique has been used to detect the quantity and route of renal arteries, replacing conventional arteriography in evaluation, vascular anatomy study and diagnosis of renal vascular pathologies (PALMIERI et al., 2011).
The presence of multiple renal arteries requires greater caution in surgical and radiological procedures, because its presence can result in modifications of the surgical procedures.If homeostatic controls of the renal arteries are necessary, they increase the complexity of the surgery, besides the high correlation with renal pathologies, compared to kidneys supplied by a single artery (FOX; YALIN, 1979;SAMPAIO;PASSOS, 1992;LÓPEZ et al., 2014).Still on the kidney transplantation topic, the rate of stenosis in multiple renal arteries is also higher.(BENEDETTI et al., 1995).
Given the importance and relevance of this anatomic arterial variation, its knowledge must be carried out in the execution of surgical, experimental and radiological procedures, because the existence of multiple arteries is an aggravating factor for the conduction of correct procedures.ramos da aorta abdominal.A duplicidade de artéria renal é uma variação anatômica definida como uma flexibilidade normal na topografia e morfologia das estruturas do corpo, que em termos funcionais não há prejuízo do órgão, uma vez que a irrigação arterial do mesmo é um fator vital para a sobrevivência dos tecidos.Neste contexto, o estudo de caso tem grande importância, sendo que o conhecimento das variações dos vasos renais auxilia na estruturação da anatomia cirúrgica e em estudos radiológicos e clínicos para humanos.Às variações na anatomia vascular são frequentemente encontradas, no homem, é caracterizada por vários autores, com uma prevalência de vasos múltiplos que ocorre em cerca Double renal artery… SABEC -PEREIRA, D. K.et al.