Concurrent variations of left testicular vessels

Abstract

Knowledge of variations of the testicular vessels is essential for urologists, radiologists, and surgeons in general, as iatrogenic injuries of these vessels may affect the spermatogenesis severely. Though variations of testicular vessels are common, combined variations of these vessels are rare. We observed concurrent variations of left testicular vessels in an adult cadaver aged 70 years. There were two gonadal arteries on the left side, both of which arose from the abdominal aorta. The superior one among them hooked around the left renal vein and the left suprarenal veins. There were three testicular veins at the deep inguinal ring, but they formed a plexus of veins at the posterior abdominal wall, which reduced into two veins. These two testicular veins terminated into the left renal vein independently. The deep inguinal ring was congested with the presence of five vessels. This variation could increase the possibility of varicocele.

Introduction

The left testicular artery is a branch of abdominal aorta. Usually, it arises at the level of origin of the renal artery and passes down retroperitoneally to the deep inguinal ring. It passes through the deep inguinal ring and reaches the scrotum through the spermatic cord. Some of the reported variations of left testicular artery include its duplication [1], high or low origin and passage through a fenestration in the left renal vein [2]. A detailed account of possible variations based on previous studies has been given by Paraskevas et al. (2014) [3].

The left testicular vein is formed by the union of the veins of the pampiniform plexus at variable levels. It usually terminates into the left renal vein. However, its duplication and variant terminations have been reported [4]. It has been noted from the past studies that the variations of testicular vessels are more common on the left side [5].

This report discusses the clinical implications of the combined variations of the left testicular vessels. The aim of this report is to alert the surgeons and radiologists about the possibility of multiple left testicular vessels.

Case Report

During routine dissection classes, combined variations of the left testicular vessels was observed in an adult male cadaver aged 70 years. There were two left testicular arteries. The superior one among the two arose from the abdominal aorta at the level of origin of left renal artery (2 inches above the origin of inferior mesenteric artery) and ran down by hooking around the left suprarenal and renal veins. The inferior left testicular artery took its origin from the anterior surface of the aorta about one inch below the level of the origin of renal artery (one inch above the origin of the inferior mesenteric artery). Both these arteries ran down to the deep inguinal ring and then entered the spermatic cord. They reached the scrotum through the spermatic cord and supplied the testis, epididymis, and vas deferens. The pampiniform plexus reduced into three left testicular veins (medial, intermediate and lateral) at the deep inguinal ring. They further divided into a plexus at the posterior abdominal wall. Finally, two left testicular veins (medial and lateral) emerged from this plexus, and they joined the left renal vein independently. The medial among the two veins was larger. The lateral vein opened into the left renal vein very close to the hilum of the kidney. The left deep inguinal ring was congested due to the presence of multiple testicular vessels. The variations observed were unilateral. There were no other associated anomalies in the abdomen of this cadaver. The variations are shown in Figs. 1–4.

Fig. 1.

Dissection of the left side of the posterior abdominal wall showing the panoramic view of the left testicular vessels. DIR, deep inguinal ring; ITV, intermediate testicular vein; LTV, lateral testicular vein; MTV, medial testicular vein; ITA, inferior testicular artery; LK, left kidney; AA, abdominal aorta; LRV, left renal vein; LSG, left suprarenal gland; STA, superior testicular artery; M, medial; L, lateral; S, superior; I, inferior.

Fig. 2.

Closer view of the upper part of the left testicular vessels. IMA, inferior mesenteric artery; ITA, inferior testicular artery; AA, abdominal aorta; MTV, medial testicular vein; LRV, left renal vein; LSV, left suprarenal vein; LSG, left suprarenal gland; STA, superior testicular artery; LTV, lateral testicular vein; LK, left kidney; M, medial; L, lateral; S, superior; I, inferior.

Fig. 3.

Closer view of the lower part of the left testicular vessels. DIR, deep inguinal ring; LTV, lateral testicular vein; ITV, intermediate testicular vein; MTV, medial testicular vein; STA, superior testicular artery; ITA, inferior testicular artery; M, medial; L, lateral; S, superior; I, inferior.

Fig. 4.

A simplified schematic diagram of the variant gonadal vessels. LK, left kidney; LSG, left suprarenal gland; MTV, medial testicular vein; IVC, inferior vena cava; IMA, inferior mesenteric artery; LRV, left renal vein; AA, abdominal aorta; LTV, lateral testicular vein; STA, superior testicular artery; ITA, inferior testicular artery; ITV, intermediate testicular vein; DIR, deep inguinal ring.

Discussion

Testicular vessels show frequent variations. Nallikuzhy et al. (2018) [5] have done a meta-analysis to classify the variations of the testicular vessels and have found that variations of left testicular vessels are more common than the right. They have reported the left testicular artery arose from the aorta at a variable level in 1.45% cases, from the renal artery in 4.97% cases and was duplicated in 2.14% cases. Naito et al. (2006) [6], have reported a case where the left testicular artery originated from the aorta at a higher level and arched over the left renal vein before descending further. They opine that this type of arching could be the cause of renal vein hypertension [6]. Rarely the testicular artery can arise from abdominal aorta and divide into two branches along with its course. One such case has been reported by Rusu (2006) [7]. Mao and Li (2015) [8] has reported the origin of an accessory renal artery from the left testicular artery. The left testicular artery can take its origin from a middle mesenteric artery. One such rare case has been reported by Naito et al. (2011) [9].

As far as the embryological development of the testicular arteries is concerned, they develop from the mesonephric branches of the abdominal aorta. Initially a total number of 9 pairs of mesonephric arteries exist and they are arranged in three groups. The cranial group, with first and second mesonephric arteries, middle group of third, fourth and fifth arteries and a lower group consisting of the rest of them. Usually, renal arteries arise from the middle group and the gonadal arteries arise from the lower group of these arteries. Doubling of the testicular artery is due to the persistence of one of the upper groups of mesonephric arteries [10].

Variations of the left testicular veins are more common than the right. As far as the number is concerned the left testicular veins may be single, duplicated, triplicated, quadruplet or multiple. In the study by Nallikuzhy et al. (2018) [5], duplication was seen in 16.61%, triplication in 2.15% and quadrifurcation in 0.12% cases. A case of quadrifurcation has also been reported by Lee et al. (2019) [11]. A case of terminal bifurcation of the left testicular vein has been reported by Nayak et al. (2013) [12]. Tubbs et al. (2005) [13], have reported an unusual case of testicular veins where both right and left testicular veins divided before termination and the lateral division joined subcostal vein on both sides.

The testicular veins develop from the lower part of the subcardinal veins, below the level of intersubcardinal anastomosis. The subcardinal veins also give rise to the renal veins and the renal segment of inferior vena cava [14]. The anomalies of the testicular veins are believed to be due to the dysplasia of the subcardinal veins during early stages of embryonic development [15].

Knowledge of variation in the number and mode of termination of left testicular vein is important during abdominal surgeries. Multiple testicular veins could congest the deep inguinal ring area, which could increase the possibility of blood stagnation in the pampiniform plexus. The presence of multiple veins in the retroperitoneal area may result in iatrogenic bleeding during retroperitoneal surgeries.

The current case is a rare combination of duplication of left testicular vein and artery. One of the arteries was hooking around the termination of the left suprarenal vein into the renal vein. This artery could hinder the venous drainage in suprarenal vein and left renal vein. The lateral vein among the two testicular veins being reported here was terminating in the left renal vein almost in the hilum of the kidney. It is vulnerable to injury during kidney transplant surgeries and therapeutic embolization procedures.

In conclusion, though variations of the left testicular vein and not uncommon, combined variations are rare. Having two arteries and three veins at the deep inguinal ring area, a plexus of veins at the posterior abdominal wall and a testicular vein draining into the renal vein at the hilum of the kidney makes this case special. Knowledge of this variation could be important to surgeons, urologists and nephrologists.

Funding Statement

Funding None.