The ureters are tubes made of smooth muscle that propel urine from the kidneys to the urinary bladder. In a human adult, the ureters are usually 20–30 cm (8–12 in) long and around 3–4 mm (0.12–0.16 in) in diameter. The ureter is lined by urothelial cells, a type of transitional epithelium, and has an additional smooth muscle layer that assists with peristalsis in its lowest third.
In medicine, a catheter (/ˈkæθətər/) is a thin tube made from medical grade materials serving a broad range of functions. Catheters are medical devices that can be inserted in the body to treat diseases or perform a surgical procedure. Catheters are manufactured for specific applications, such as cardiovascular, urological, gastrointestinal, neurovascular and ophthalmic procedures. The process of inserting a catheter is catheterization.
Interventional radiology (IR) is a medical specialty that performs various minimally-invasive procedures using medical imaging guidance, such as x-ray fluoroscopy, computed tomography, magnetic resonance imaging, or ultrasound. IR performs both diagnostic and therapeutic procedures through very small incisions or body orifices. Diagnostic IR procedures are those intended to help make a diagnosis or guide further medical treatment, and include image-guided biopsy of a tumor or injection of an imaging contrast agent into a hollow structure, such as a blood vessel or a duct. By contrast, therapeutic IR procedures provide direct treatment—they include catheter-based medicine delivery, medical device placement, and angioplasty of narrowed structures.
Urinary retention is an inability to completely empty the bladder. Onset can be sudden or gradual. When of sudden onset, symptoms include an inability to urinate and lower abdominal pain. When of gradual onset, symptoms may include loss of bladder control, mild lower abdominal pain, and a weak urine stream. Those with long-term problems are at risk of urinary tract infections.
Pyelonephritis is inflammation of the kidney, typically due to a bacterial infection. Symptoms most often include fever and flank tenderness. Other symptoms may include nausea, burning with urination, and frequent urination. Complications may include pus around the kidney, sepsis, or kidney failure.
Hydronephrosis describes hydrostatic dilation of the renal pelvis and calyces as a result of obstruction to urine flow downstream. Alternatively, hydroureter describes the dilation of the ureter, and hydronephroureter describes the dilation of the entire upper urinary tract.
The Seldinger technique, also known as Seldinger wire technique, is a medical procedure to obtain safe access to blood vessels and other hollow organs. It is named after Sven Ivar Seldinger (1921–1998), a Swedish radiologist who introduced the procedure in 1953.
Pyonephrosis is an infection of the kidneys' collecting system. Pus collects in the renal pelvis and causes distension of the kidney. It can cause kidney failure.
Vesicoureteral reflux (VUR), also known as vesicoureteric reflux, is a condition in which urine flows retrograde, or backward, from the bladder into one or both ureters and then to the renal calyx or kidneys. Urine normally travels in one direction from the kidneys to the bladder via the ureters, with a one-way valve at the vesicoureteral (ureteral-bladder) junction preventing backflow. The valve is formed by oblique tunneling of the distal ureter through the wall of the bladder, creating a short length of ureter (1–2 cm) that can be compressed as the bladder fills. Reflux occurs if the ureter enters the bladder without sufficient tunneling, i.e., too "end-on".
In urology, voiding cystourethrography (VCUG) is a frequently performed technique for visualizing a person's urethra and urinary bladder while the person urinates (voids). It is used in the diagnosis of vesicoureteral reflux, among other disorders. The technique consists of catheterizing the person in order to fill the bladder with a radiocontrast agent, typically diatrizoic acid. Under fluoroscopy the radiologist watches the contrast enter the bladder and looks at the anatomy of the patient. If the contrast moves into the ureters and back into the kidneys, the radiologist makes the diagnosis of vesicoureteral reflux, and gives the degree of severity a score. The exam ends when the person voids while the radiologist is watching under fluoroscopy. Consumption of fluid promotes excretion of contrast media after the procedure. It is important to watch the contrast during voiding, because this is when the bladder has the most pressure, and it is most likely this is when reflux will occur. Despite this detailed description of the procedure, at least as of 2016 the technique had not been standardized across practices.
A ureteral stent, or ureteric stent, is a thin tube inserted into the ureter to prevent or treat obstruction of the urine flow from the kidney. The length of the stents used in adult patients varies between 24 and 30 cm. Additionally, stents come in differing diameters or gauges, to fit different size ureters. The stent is usually inserted with the aid of a cystoscope. One or both ends of the stent may be coiled to prevent it from moving out of place; this is called a JJ stent, double J stent or pig-tail stent.
Pyelogram is a form of imaging of the renal pelvis and ureter.
Percutaneous transhepatic cholangiography, percutaneous hepatic cholangiogram (PTHC) is a radiological technique used to visualize the anatomy of the biliary tract. A contrast medium is injected into a bile duct in the liver, after which X-rays are taken. It allows access to the biliary tree in cases where endoscopic retrograde cholangiopancreatography has been unsuccessful. Initially reported in 1937, the procedure became popular in 1952.
A ureterostomy is the creation of a stoma for a ureter or kidney.
Percutaneous nephrolithotomy (PCNL) is a minimally-invasive procedure to remove stones from the kidney by a small puncture wound through the skin. It is most suitable to remove stones of more than 2 cm in size and which are present near the pelvic region. It is usually done under general anesthesia or spinal anesthesia.
Renal biopsy is a medical procedure in which a small piece of kidney is removed from the body for examination, usually under a microscope. Microscopic examination of the tissue can provide information needed to diagnose, monitor or treat problems of the kidney.
Bladder outlet obstruction occurs when urine is unable to flow from the kidneys through the ureters and out of the bladder through the urethra. Decreased flow of urine leads to swelling of the urinary tract, called hydronephrosis. This process of decreased flow of urine through the urinary tract can begin as early as during intrauterine life and it prevents normal development of fetal kidneys and fetal urine. Low levels of fetal urine leads to low amniotic fluid levels and incomplete lung maturation. Older children and adults can also experience bladder outlet obstruction; however, this process is usually reversible and isn't associated with as many poor outcomes as in infants with congenital bladder outlet obstruction.
Percutaneous intentional extraluminal revascularization is a percutaneous technique used in interventional radiology for limb salvage in patients with lower limb ischemia due to long superficial femoral artery occlusions. This method is intended for those patients who make poor candidates for infrainguinal arterial bypass surgery. A guide wire is intentionally introduced in the subintimal space, after which balloon dilatation is performed to create a new lumen for the blood to flow through. The technique is not without complications but may serve as a "temporary bypass" to provide wound healing and limb salvage.
Renal ultrasonography is the examination of one or both kidneys using medical ultrasound.
Ureteric stricture (ureteral stricture) is the pathological narrowing of the ureter which may lead to serious complications such as kidney failure.
