2. Summarize the absence and hypoplasia of ureter. In embryonic stage, one side of ureteral bud is undeveloped or hypoplastic, which is characterized by small or atresia of ureteral cavity and formation of fibrous cord. Some lumen is intermittently narrowed, and the blind end of ureter expands into cyst.
If the contralateral isolated renal function is normal, the absence of ureter is not easy to find, and it is only occasionally noticed when there is cyst in ureter hypoplasia. Some of them accidentally found that the upper urinary tract of the affected side was not developed during intravenous urography, while the contralateral solitary kidney had compensatory hyperplasia. Cystoscopy showed that the triangular area of bladder was asymmetric, and the ureteric crest on one side was flat without orifice. In the case of ureteral hypoplasia, the orifice can be found in the normal position, and the ureteral catheter is blocked, and the retrograde pyelography can be used to make a definite diagnosis.
The absence or hypoplasia of ureter generally does not require treatment, and only local cyst formation or secondary infection can make surgical exploration or resection.
The etiology of giant ureter is unclear, which may be due to the decrease or absence of parasympathetic ganglion cells in the end wall of ureter, resulting in local functional obstruction, inability to conduct peristaltic waves, urine stagnation, upper urinary tract dilatation and hydronephrosis, and the ureter itself is not elongated, tortuous, obstructed, and the ureteral orifice is relaxed. About half of the patients' bladder is accompanied by neuromuscular dysplasia, forming an expanded tension-free bladder, and then bladder catheter reflux occurs. Secondary megaureter is mostly caused by distal obstruction, such as ectopic ureter opening and stricture at the opening.
A few patients may have no symptoms. Common symptoms include pyuria, frequent urination, hematuria, pain in waist or bladder area, etc. These symptoms may appear independently or simultaneously. With the aggravation of renal damage, renal failure will occur. Intravenous urography can find ureteral dilatation, and cystoscopy and ureteral catheter insertion confirm that there is no obstructive lesion.
If the ureter is slightly enlarged and the renal function is still good, conservative treatment can be taken, mainly anti-infective drugs, and urography can be observed regularly. When the lesion is confined to the junction of ureter and bladder, the ureter segment that can not conduct peristaltic waves is removed and the proximal stump is transplanted into bladder. If the ureter is obviously dilated, plastic repair of ureter should be performed at the same time. Tension-free bladder with vesicoureteral reflux, transurethral partial cystectomy or cystostomy can sometimes achieve certain curative effect. If there is renal atrophy, perform nephroureterectomy.
3. After1inferior vena cava, the right ureter is located on the plane of the third and fourth lumbar vertebrae. It goes forward from the inferior vena cava, passes between the aorta and the inferior vena cava, and then returns to the outside to enter the bladder, which is caused by the abnormal development of the inferior vena cava. In the embryonic stage, the posterior kidney rises from the pelvis to the waist and passes through the venous ring composed of venous trunks and branches. For example, the right posterior main vein in front of the venous ring does not contract, and venous blood continues to flow back along this vein to form the inferior vena cava, and the ureter is located behind the inferior vena cava.
The inferior vena cava compresses the ureter, making the urine flow stop, easily causing hydronephrosis and infection of the renal pelvis and ureter, and causing persistent or intermittent pain in the middle abdomen or ribs. Patients with secondary stones often have hematuria. Intravenous urography showed hydronephrosis in the right kidney, and the ipsilateral ureter was bent in the shape of "S" or sickle, and the medial side was bent to the front of the spine. For the ureter suspected to be located behind the inferior vena cava, the catheter was inserted through the right ureter through cystoscope; If necessary, the catheter is inserted into the inferior vena cava through the great saphenous vein. Abdominal X-ray can show the anatomical relationship between the right ureter and the inferior vena cava to make a clear diagnosis.
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