ABNORMAL PATTERN OF RENAL AND GONADAL VEINS AND ITS DEVELOPMENTAL CORRELATION

Address for Correspondence: Dr. Krishna Gopal, Associate Professor, Department of Anatomy, Sri Guru Ram Rai Medical College And Hospital, Patel Nagar, Dehradun. Uttaranchal, India. E-Mail: drkrish2007@gmail.com Introduction: The variations of the renal veins are not as common as arteries. The renal veins are formed near the hilum by the union of interlobar veins in front of the renal artery. Variant anatomy can pose a problem at both organ recovery and implantation. Materials and Methods: This study included thorough dissection of 25 cadavers obtained from department of Anatomy, Sri Guru Ram Rai Institute of medical and health sciences Dehradun following standard guidelines. All the Variation of the right and left gonadal veins and renal veins were observed and reported. Results: Out of 25 cadavers dissected in present study, the accessory renal veins was encountered in 5 (20%) cadavers in right side. one cadaver (4%) the right gonadal vein drains at the junction of right accessory renal vein and inferior vena cava. The right gonadal vein drains into the right renal vein in two (8%) cadavers and it also drains into the left renal vein in one cadaver (4%). Conclusion: The numerous variations like presence of accessory renal vein, abnormal drainage of gonadal veins were observed in this study. Incidence of variations of testicular veins was noted mostly on the right side. These variations are of clinical significance are very useful for the anatomists, radiologists, anesthesiologists, and general surgeons.

The present study was undertaken on twenty five adult embalmed cadavers of known sex, obtained from department of Anatomy, Sri Guru Ram Rai Institute of medical and health sciences Dehradun.The abdominal cavity was opened and abdominal viscera were systemically removed according to Cunningham manual of practical Anatomy.The testicular veins were traced from the testis to their termination into the Inferior vena cava and left renal vein.All the Variation of the right and left testicular veins and accessory renal veins were observed and the photographs were taken with the help of digital camera.

MATERIALS AND METHODS
In the present study, the accessory renal veins were seen on right side in 5 cadavers [Table -1  found in any cadaver.During dissection it were also observed in one case, that on the right side, the gonadal vein drained directly into the left renal vein instead of inferior vena cava.This type of variation has not been reported earlier.Gupta et al [18] explained that Complex embryogenesis the shifting of venous arrangement to the right possibly discouraging any retention of accessory left sided renal veins.Thus rightsided anatomical variations of the renal vein are more common.These variations can lead to significant surgical complications or even life threatening events if unrecognized.

CONCLUSION
In the present study we were found the incidence of presence of accessory right renal vein drain into the inferior vena cava.It were also revealed that the right gonadal vein drain into the right renal vein or the left renal vein instead of inferior vena cava.Incidence of variations of testicular veins was noted mostly on the right side.Anatomical knowledge of the presented variants is of great importance for the appropriate selection of operative techniques during surgical interventions as well as for postoperative management.
I am grateful to Dr. Alok chaudhary for her unfailing support and professional insight in the preparation of this article.I also thank the staff members of department of anatomy for assisting in the study.

INTRODUCTION
International Journal of Anatomy and Research, Int J Anat Res 2017, Vol 5(3.2):4295-98.ISSN 2321-4287 DOI: https://dx.doi.org/10.16965/ijar.2017.316vein into the inferior vena cava at the level of L2 vertebra.The right renal vein is shorter (2-4 cm) than the left (6-10 cm).It receives blood only from the right kidney, whereas the left renal vein receives the left adrenal and gonadal veins in addition to the vein coming from the kidney.It were reported that the presence of renal arterial abnormalities predominates the venous abnormalities.Variant anatomy can pose a problem at both organ recovery and implantation.Variations in the origin, course & termination of renal veins, mainly resulting from the errors of the embryological development, are frequently observed [1].In an era of renal transplantation and changing trend in favor of conservative renal surgery, the knowledge of the anatomy and variational patterns of renal veins is important for such surgeries.Development: The kidneys arise from the metanephros in the developing embryo [2] and as the embryo grows, the kidneys migrate cranially from the pelvis to the normal position, and at the same time undergo a 90 0 axial rotation from horizontal to medial, while the hilum rotates from its anterior facing position to a medial facing one.The development of the renal veins is a complex process with many possible alternative patterns of formation.This is particularly true on the left side because of the communication of the left renal vein with the adrenal, gonadal, phrenic and hemiazygos veins.As per literature [3] and available data right testicular vein develops from lower part of right sub cardinal vein.Gonadal vein develops from caudal part of subcardinal vein and it drains into the suprasubcardinal anastomosis.In the right side, this supra-subcardinal anastomosis and also a small portion of Subcardinal vein are incorporated into the formation of inferior vena cava, so right gonadal vein usually drains into the inferior vena cava.Embryologically, the bilateral symmetrical cardinal venous system becomes a unilateral right sided inferior vena cava.Initially two renal veins are present on each side at the ventral and dorsal plane.Convergence of both tributaries results in the single vessel formation.Persistence of these two veins leads to the presence of accessory or additional renal veins [4].

Fig. 1 :
Fig. 1: Showing right gonadal vein drains at the junction of accessory renal vein and inferior vena cava.