Many people have heard or enjoyed Tchaikovsky’s famous Nutcracker. But the two seemingly completely unrelated aspects of the clip and hematuria come together in a urologic condition with an interesting name: Nutcracker Syndrome (NCS). Nutcracker Syndrome (NCS) is actually a relatively rare vascular problem in which, due to a developmental problem, the left renal vein is pinched by two large arteries (the aorta and the superior mesenteric artery), resulting in intermittent hematuria and a series of clinical symptoms that have been graphically described as Nutcracker Syndrome. The specifics of NCS Speaking of NCS, it is also important to mention the Nutcracker Phenomenon (NCP) – i.e., renal vein obstruction, i.e., compression of an artery adjacent to the left renal vein that causes the clinical symptoms, whereas NCS refers specifically to compression of the renal vein by the aorta and the superior mesenteric artery, which is a part of the NCP. Isn’t it a bit complicated? In the vast majority of cases the left renal vein is affected because the abdominal aorta and its major collateral branches are located on the left side. The abdominal aorta is the largest artery in the abdomen, and the superior mesenteric artery emanates from the abdominal aorta to provide blood supply to the pancreas and most of the intestinal tract. The renal vein, on the other hand, is the inferior vena cava that returns blood from the kidneys to the right side of the aorta. Normally, the left renal vein also passes between the two arteries, but it is not compressed due to the large angle between the two arteries and the lining of fatty tissue. When the angle between the two arteries is too small, the left renal vein becomes compressed like a nutcracker. When the left renal vein is compressed, blood flow out of the kidneys is blocked, and some of the blood seeks an outlet in the peripheral branches of the renal vein, causing it to dilate and stagnate, and the return area of the branches to be blocked, resulting in a range of clinical symptoms. Who is at risk for NCS and why NCS is relatively rare in both adults and children, and the incidence and cause of the disease is currently unknown. It appears to be more common in women in adulthood and sometimes occurs after rapid weight loss. Most patients with NCS present with abdominal pain and hematuria, but there are those who are completely asymptomatic, especially in children.There is no hereditary predisposition to NCS, and it is hypothesized that it may be the result of multiple births or certain factors in pregnancy. Manifestations and Diagnosis of NCS NCS Symptoms NCS has many symptomatic manifestations and can be asymptomatic, especially in children. Common symptoms include: low back and abdominal pain, hematuria, pelvic bruising or lower abdominal cramps and varicose veins in the abdominal wall and vulva in women, painful intercourse in women, and varicose veins in men; other symptoms include varicose veins in the lower extremities, severe menstrual cramps, pain with urination, hemorrhoids or varicose veins in the labia, and weakness. Diagnosis of NCS Diagnosing NCS is not easy and sometimes challenging because the clinical presentation is similar and not specific to urinary tract or gynecological symptoms, and your doctor will often need to rule out other conditions before considering NCS. your doctor will need you to describe your symptoms in detail, and will also carefully review your medical history and perform an appropriate physical examination, taking into account any physical abnormalities. During this process, the doctor will also perform comprehensive laboratory and imaging tests, blood and biochemistry, urine routine, urine culture, urine cytology, CT or MRI, and even cystoscopy or kidney biopsy. Doppler ultrasound, CT and MRI are very helpful in confirming the diagnosis. Treatment of NCS The treatment of NCS depends on age, symptoms and severity of the condition. In some cases, such as those under the age of 18 (which may change as the body develops) or those who are adults but do not have severe symptoms. For patients with NCS who have mild symptoms and do not want surgery, there is an option to wait and watch while the doctor tests regular urine tests. Since some patients’ symptoms can resolve over time, regular urine observation by the doctor can be used to see if the situation improves or if further action should be taken. For other patients who need treatment, treatment options include endovascular stents, surgery, and extravascular bracing. Endovascular stenting An endovascular stent is a small piece of woven metal mesh that is placed inside a compressed renal vein through a vascular intervention to act as a support to restore smooth blood flow. To place the stent, the doctor makes a puncture at the base of the thigh and places a flexible guidewire into a vein (called the femoral vein). A thin catheter is then followed along the guidewire, through which a contrast medium is injected and used with the guidewire to reach the compressed renal vein. A stent is released through the catheter and spread to provide internal support. This is called a minimally invasive vascular intervention and has the advantage of minimal trauma and a short hospital stay with quick recovery, but there is a risk of the stent migrating, growing blood clots, and the need for anticoagulant medication. Vascular Surgery In the following serious cases, such as persistent recurrent hematuria leading to anemia, clot draining renal colic, severe abdominal pain, and observation for 12-24 months without relief, doctors may recommend vascular surgeries to reduce the pressure on the left renal vein, including left renal vein transposition and reanastomosis, renal vein bypass (bypass), and autologous kidney transplantation. Left renal vein transposition (left: before transposition right: after transposition) left: bypass right: autologous kidney transplantation to the lower abdomen Extravascular support There are not many reports of extravascular support, where the pressure on the two arteries is relieved by utilizing a support made of special material outside the left renal vein, and recently, there are even reports of the application of a titanium alloy support made by 3D-printing technology to be placed through laparoscopic technique. Theoretically, there is no interference with the interior of the vessels and no need for anticoagulants, but the technique of vessel freeing is technically demanding. The effect of the support on the blood vessels in the long term remains to be seen. Left: 3D printed titanium stent, right: CT reconstruction image after placement How long does it take to recover from NCS treatment? Pain or other symptoms tend to decrease quickly in the more symptomatic cases of NCS, but not so quickly in the less symptomatic cases. Vascular stenting: can be up to 2-3 months later as the body needs new tissue to cover it and this takes time. Anticoagulant medication is taken for as long as the surgeon advises. Surgery: It takes about 3 months for the blood vessel to repair properly.