Posterior Tributary Research Articles

Anatomical Variations in Arrangement of Renal Hilar Structures and its Applied Importance: A Cadaveric Cross-sectional Study among North East Population of India

Introduction: The hilum of the kidney leads into a central renal sinus filled with the renal pelvis and renal vessels. The classical arrangement of the structures present is the renal vein, renal artery, and renal pelvis, from anterior to posterior. Previous studies have shown many variations in the arrangement of the structures in the renal hilum; however, there is a lack of literature on this topic in the North-east region of India, where many communities and tribes reside. Aim: To evaluate both the classical and anatomical variations in the arrangement of the renal hilar structures in human cadavers. Materials and Methods: The present study was a cadaveric cross-sectional study conducted in the Department of Anatomy at Assam Medical College, Assam, India, involving 160 specimens from 80 cadavers, both adult and foetal (≥36 weeks), from July 2013 to June 2014. Among these, 15 were adult cadavers and 65 were perinatal cadavers (11 male and 4 female adults; 28 male and 37 female perinates). The relations of the structures, i.e., renal artery, renal vein, and renal pelvis present in the renal hilum, were studied in an anterior-posterior manner after meticulous dissection. Results: In the present study, the majority of specimens exhibited hilar structures arranged in a VAP pattern (67 kidneys, 41.88%), with a higher occurrence on the left-side (37 kidneys, 23.1%) compared to the right-side (30 kidneys, 18.7%). This was followed by a VAPA pattern (28 kidneys, 17.5%). Variations in the arrangement of hilar structures other than the classical arrangement were observed in more than 59% (93 kidneys) of the specimens. It was noted that the anterior and posterior divisions of the renal artery and the anterior and posterior tributaries of the renal vein occupied the pre-hilar and hilar regions rather than the main trunks. Conclusion: It was observed that the arrangement of the structures present in the renal hilum exhibits a wide spectrum of variations. Knowledge of these variations may be beneficial not only for anatomists but also for urologists and radiologists, as it may help prevent or at least minimise the incidence of intraoperative injuries and post-operative complications. Urological procedures such as nephrectomy and renal transplant operations require careful dissection and separate ligation of the renal vessels present in the renal hilum to prevent arteriovenous fistula and massive haemorrhage. Prior knowledge of unusual arrangements of the hilar structures may assist surgeons in avoiding inadequate ligation of vessels and minimising complications.

Aberrant internal jugular vein penetrates posterior skull base

The internal jugular vein (IJV) is responsible for the venous drainage of the brain as well as deep portions of the face and neck. The IJV originates at the base of the skull in the posterior compartment of the jugular foramen and courses in the vertical direction, within the lateral portion of the carotid sheath.1 Anatomical variations of IJV is reported to be as rare as 4 per 10,000 births. Most of the reported variations include bifurcation, duplication, fenestration, trifurcation, and posterior tributary.

Anatomical variations of Internal Jugular Vein: A Review

Introduction Internal Jugular Vein (IJV) has a stable anatomy. However, a number of variations have been reported in literature. We aimed to accumulate data pertaining to these anatomical variations as noted by surgeons and anatomists. We also present very rare cases of posterior tributary of IJV to supplement our review.

Surgical review of the anatomical variations of the internal jugular vein: an update for head and neck surgeons.

The internal jugular vein is one of the major vessels of the neck. The anatomy of this vessel is considered to be relatively stable. It is an important landmark for head and neck surgeons as well as the anaesthetists for both diagnostic and therapeutic purposes. We present two case reports of the posterior tributary of the internal jugular vein and review the surgical literature regarding anatomical variations of the vein. A total of 1197 patients from 27 published papers were included in this review. Of these patients, 99.6% had neck surgery and the rest were cadaveric dissections. Anatomical variations of the internal jugular vein were found in 2% of the patient cohort (n = 40). The majority of these patients had either bifurcation or fenestration of the vein. The posterior tributary of the internal jugular vein is unusual and is scarcely reported in the literature (three cases). Knowledge of variations in the anatomy of the internal jugular vein assists surgeons in avoiding complications during neck surgery and preventing morbidity. Two rare cases of posterior branching of the internal jugular vein and experience of other surgeons are demonstrated in this extensive review.

Multiple variations of the renal and testicular vessels: possible embryological basis and clinical importance

During routine dissection of the abdominal cavity of a 55-year-old African male cadaver, multiple anomalies including renal and testicular vessels were encountered. The right kidney was supplied by three right hilar renal arteries arising from the abdominal aorta at different vertebral levels whereas only one left renal artery supplied the left kidney. On the right three renal veins drained the kidney into the inferior vena cava. In contrast, the left kidney was drained by a single renal vein which received a large primary posterior tributary. The primary posterior tributary had three tributaries from the posterior lumbar region. The right testis had two sources of arterial supply; one from the subcostal artery and another from the abdominal aorta. The left testis was supplied normally by a single testicular artery. The right testis was drained by four testicular veins as follows: one drained into the subcostal vein, the other two drained separately for a longer course and joined shortly before draining into the right main renal vein, the fourth one drained into the anterior aspect of the inferior vena cava at the level of the second lumbar vertebra. On the left, the testicle was drained by two testicular veins which travelled separately from the deep inguinal ring and joined shortly before they drain into the left renal vein. This variation may represent an immature form of complicated development of kidneys and testes. Additionally, emphasis must be put on preoperative vascular examination to avoid surgical complications from variant vessels in this region.

Associations of anterior accessory or thigh posterior tributary and great saphenous reflux patterns in early stages of chronic venous valvular insufficiency

Varicose veins are a common disorder. Extensive ultrasound (US) mapping of lower extremity chronic venous valvular insufficiency includes the great saphenous vein (GSV), anterior accessory saphenous vein (AASV) and thigh posterior tributary to GSV such as the posterior accessory saphenous vein (PTSV, PASV). The aim of this study was to determine associations between GSV-AASV-PTSV (including PASV) reflux in a specific sample population of Southern Brazilian women, mostly euro descendents, with telangiectasias, reticular veins, varices and/or intermittent edema. US performed in 1016 extremities of 513 women, 43±18 (18-81) years old were included. Women with previous venous thrombosis, surgery, suspicion of pelvic congestion syndrome, and men were excluded. Small saphenous vein and related thigh veins were excluded from analysis. GSV-AASV-PTSV reflux patterns were analyzed; prevalence was compared using χ2 statistics. Reflux prevalence in AASV and/or thigh PTSV was 5.8% (59/1016): 1.3% at PTSV (n=13) and 4.5% at AASV (n=46), significantly lower than GSV reflux: 72% (n=727) (P<0.001). AASV and/or PTSV reflux was associated with GSV reflux (81%, n=48/59); common pattern was diffuse reflux, starting at AASV/PTSV saphenous junctions (56%, n=33/59; otherwise, short, non-diffuse reflux was noted in part of the AASV/PTSV evaluated. Isolated AASV or PTSV reflux was rare (1%, n=11/1016): 9 at the AASV, and 2 at the PTSV. US mapping of AASV/PTSV in early stages of disease, in women without pelvic congestion syndrome, increased reflux detection by 1%, and improved definition of reflux patterns in about 6% of the extremities.

Medial pectoral pedicle is a reliable landmark for axillary lymph node dissection

The anatomical orientation of structures in the axilla has not been well studied, although it is essential for a neat and safe dissection. The objective of this study was to determine the relations between neurovascular structures in the axilla as they were encountered during axillary lymph node dissection (ALND) for breast cancer. This was a prospective study of 29 consecutive ALNDs accompanying either mastectomy or wide local excision. The dissections were conducted in a stepwise manner and the orientation of the structures was determined as the dissections advanced from superficial to deeper planes. The medial pectoral pedicle was the most superficial neurovascular structure encountered during the dissections and was curled around the lateral border of the pectoralis minor muscle in most cases. The intercostobrachial nerve lay 1-2cm behind and below, and the axillary vein was located 2-3cm behind and above the pedicle. The long thoracic nerve was constantly found 2-3cm behind the intercostobrachial nerve. The thoracodorsal nerve was always accompanied by a posterior tributary of the axillary vein. Relations between neurovascular structures in the axilla are predictable. The medial pectoral pedicle, which is consistently found and superficially located, could be used as a landmark for ALND.

A review of the anatomical variations of the posterior tributaries of the left renal vein

Variations of the posterior tributaries of the left renal vein (LRV) are frequently encountered during various urological and vascular procedures. This can be explained by the complex embryological and anatomical arrangements of these tributaries, as well as variations in their nomenclature. To increase awareness of the anatomical variations of the posterior tributaries of the LRV. Twenty-one kidneys were dissected. All anatomical variations of the posterior tributaries of the LRV were recorded. This study highlights lumbar tributaries are common on the left side. A single left lumbar tributary was found entering the posterior surface of the LRV in 10 out of 11 specimens. However, their drainage patterns showed varied anatomical configurations. This cadaveric study was aimed to draw attention to surgically important variations of the posterior tributaries of the LRV. Increased awareness among surgeons can considerably reduce the potential risk of vascular injuries during renal surgery.

Ureteropelvic Junction Stenosis: Vascular Anatomical Background for Endopyelotomy

To help endourologists perform endopyelotomy safely and efficiently with a reduced risk of vascular complications, we analyzed the vascular relationships to the ureteropelvic junction in 146, 3-dimensional endocasts of the kidney collecting system together with the intrarenal arteries and veins. There was a close relationship between a prominent vessel (artery and/or vein) and the anterior surface of the ureteropelvic junction in 65.1% of the cases, including the inferior segmental artery with a tributary of the renal vein in 45.2% and an artery or vein in 19.9%. In the remaining 34.9% of the cases the anterior surface of the ureteropelvic junction was free of vessels. There was a direct relationship between a prominent vessel (artery and/or vein) and the posterior surface of the ureteropelvic junction in 6.2% of the cases, including an artery and vein in 2.1%, and just an artery in 1.4%. In all cases (3.5%) of an artery crossing at the posterior surface of the ureteropelvic junction, this vessel was the posterior segmental artery (retropelvic artery). In 2.7% of the cases the relationship of the prominent vessel was just with a posterior tributary of the renal vein, and in 20.5% a vessel crossed lower than 1.5cm. above the posterior surface of the ureteropelvic junction. Among these latter cases the vessel was an artery (posterior segmental artery) in 6.8%. In the remaining 73.3% of the cases the posterior surface was free of vessels up to 1.5cm. above the ureteropelvic junction. Due to the anatomical findings, we advise that posterior and posterolateral incisions at the ureteropelvic junction be avoided, and that deep incision alongside the ureteropelvic junction stenotic wall be done only laterally.

Anatomic bases for liver transplantation

This study gathers the anatomic implications for a good liver transplantation. During hepatic removal a left hepatic a.exists in 20% of cases; a right hepatic artery originating from the superior mesenteric a. (SMA) can be the only arterial supply in 9% of cases; the whole lesser omentum has to be removed and the SMA from 6 cm to its origin. The SMA must be freed from the celiac ganglia and its ostium removed with the celiac trunk in an aortic patch cut on the anterior side in order to avoid the renal ostia. During total hepatectomy, dissection of the portal triad is often difficult because of portal hypertension dilating accessory portal veins (parabiliary arcade) and pedicular lymphatics. Nerve plexuses are thick in front of the hepatic artery or behind the portal triad. Transection of triangular ligaments leads to the retrohepatic inferior vena cava (IVC) that must be freed from its posterior tributaries (right suprarenal vein and inferior phrenic veins flowing either into the IVC or into the hepatic veins). One big problem during hepatic replacement is the biliary anastomosis which must be well irrigated. In the recipient, dissection up to the hilum preserves hepatic and pancreatico-duodenal pedicles. The biliary tract of the graft must be cut low, behind the pancreas, and several centimeters of the gastroduodenal artery must be preserved to save hepatic and gastroduodenal pedicles.