The straight angle between the ovarian vein (or testicular vein in males in the case of varicocoele) and the renal vein has been proposed as a cause of decreased blood return.A related diagnosis is "Nutcraker Syndrome" where the left renal vein is described as being compressed between the aorta and the superior mesenteric artery. This is reported to cause collateral flow paths to open up to drain the left kidney i.e. reversed flow (reflux caudally) in the left renal vein. Pelvic Congestion Syndrome, vaginal and vulval varices, lower limb varices are clinical sequelae. Virtually all such patient are female and have been pregnant, often multiply. The ovarian vein often displays incompetent valves. This has been observed more often in women with a higher number of previous pregnancies. Pressure from the baby might hinder the return of blood through the ovarian vein. It has to be noted however that dilation of the urinary tract is a normal observation in pregnancy, due to mechanical compression and the hormonal action of progesterone. Ovarian vein dilatation might also follow venous thrombosis (clotting inside the vein). Another proposed mechanism of obstruction is when the ovarian vein and ureter both run through a sheath of fibrous tissue, following a local inflammation. This could be seen as a localised form of retroperitoneal fibrosis.Following obstruction, the ureter displays an abnormal peristalsis (contractions) towards the kidney instead of towards the bladder. This is thought to cause the colicky pain (similar to renal colic), and it is relieved after surgical decompression.
Recently, the first robot-assisted surgery was described.Another approach to treatment involves catheter-based embolisation, often preceded by phlebography to visualise the vein on X-ray fluoroscopy.Ovarian vein coil embolisation is an effective and safe treatment for pelvic congestion syndrome and lower limb varices of pelvic origin. Many patients with lower limb varices of pelvic origin respond to local treatment i.e. ultrasound guided sclerotherapy. In those cases, ovarian vein coil embolisation should be considered second line treatment to be used if veins recur in a short time period  i.e. 1–3 years. This approach allows further pregnancies to proceed if desired. Bilateral coil embolisation is not advised if a future pregnancy is possible. This treatment has largely superseded operative options.Coil embolisation requires exclusion of other pelvic pathology, expertise in endovascular surgery, correct placement of appropriate sized coils in the pelvis and also in the upper left ovarian vein, careful pre- and post-procedure specialist vascular ultrasound imaging, a full discussion of the procedure with the patient i.e. informed consent. Complications, such as coil migration, are rare but reported. Their sequelae are usually minor.If a Nutcracker compression (see below) is discovered, operative relocation of the renal vein should be considered before embolization of the ovarian vein. Stenting is not advised. Reducing outflow obstruction should always be the main objective. History
The entity was first described by Clark in 1964. Following initial scepticism and lively discussion in the medical literature, it is now recognised by many authors. == References ==