Urine formed in the kidneys enters the bladder through the ureters. Normally, a person has two kidneys and two ureters. Impaired urine outflow, due to certain pathologies, injuries or surgical interventions is manifested by severe pain in the lumbar region. Various techniques are used to eliminate the problem, including ureteral stenting.
Ureteral stenting is a minimally invasive surgical procedure, the essence of which is to install a special stent in the ureter, which restores normal urine flow.
This is a thin tube, 8 to 60 cm long. The tube has spiral mounts to prevent displacement of the stent and to fix it in the cavity of the kidney or bladder. The stent must meet several requirements: be smooth, flexible and resistant to urine. Typically, stents are made of silicone or polyurethane. To reduce urinary reactions, some stents are treated with a hydrogel to increase service life.
The size, shape and material of the ureteral stent are selected individually and depend on the anatomy of the patient, as well as the reasons for stent placement. Typically, stents have a diameter of 1.5-6 mm. To prevent displacement of the stent, one or both ends have a spiral shape.
The causes of impaired urine outflow from the kidney can be divided into two main groups: urological and non-urological.
As a rule, stenting of the ureter is performed when this procedure is indispensable. Also, this operation is considered quite simple. For these reasons, stenting has virtually no contraindications. However, in case of severe ureteral injury, pronounced inflammatory process, late stages of pelvic cancer, burdened with severe somatic pathology, as well as the patient's pregnancy, the decision on the possibility of the procedure is made by a urologist individually.
A comprehensive full-fledged preoperative examination is performed:
Hunger is shown on the day of the operation. To remove gases and clean the intestinal wall, make a cleansing enema. To prevent post-procedural infection, an antibiotic is prescribed. Before manipulation, the bladder should be emptied for free access to the cystoscope.
There are 2 ways to install a ureteral stent - retrograde transurethral and antegrade transfistular.
Retrograde (through the urethra) is the standard insertion of a stent through the urethra and bladder using an endoscope tube with a video camera and a string conductor. The operation is performed under general anaesthesia or spinal anaesthesia (the patient is conscious but does not feel anything). As a rule, the stent is made in the form of a thin metal mesh, because it simplifies its movement and proper installation. It is transported to the place of installation in a folded form, and after reaching the place of narrowing it is straightened. The straightened walls of the stent support the ureter, preventing it from narrowing. The operation is monitored by X-ray, both during and after the procedure. For a better examination, the bladder is filled with a sterile solution. After installation, the fluid is pumped out and the endoscope is removed.
Antegrade method - a stent is inserted through a puncture of the skin into the renal pelvis (the place of transition of the kidney into the ureter) and then installed in the direction of the bladder into the ureter. Manipulations are performed under X-ray control. Sometimes the procedure is performed in 2 stages - first, a catheter is placed in the renal pelvis to drain urine, and a week later - a stent.
In clinical practice, the retrograde method is used much more often.
After the operation, the patient is transferred to the hospital ward, where he will spend 1-2 days under the supervision of medical staff. In the first days, the patient may experience pain when urinating, frequent urge to go to the toilet, blood in the urine, pain in the lower abdomen and lower back. To eliminate the unpleasant consequences, the doctor will prescribe a course of painkillers and anti-inflammatory drugs, as well as antibiotics. With adequate treatment, the negative consequences go away in 3-4 days.
If there are no adverse reactions and complications, the stent is removed at least 2 weeks and at most 6 months after installation - when the urinary structures take a physiological position and the stent is no longer needed. If lifelong use is required, it is changed to a new one every 3-4 months to prevent urological infection, clogging with urine salts, damage to the mucous membrane and the formation of bedsores.
Removal of a ureteral stent takes place on an outpatient basis, under anaesthesia, and takes much less time than the procedure of its installation. There are now several ways to remove a stent: