Surgical Urology

Invasive imaging and drainage

Specialized radiopaque methods are used for a detailed assessment of the anatomy of the renal pelvis and ureters:

• Antegrade pyelography (Antegrade Pyelogram). Contrast is administered from above, directly into the collecting system. If the study is supplemented with urodynamic pressure measurements, the result is the Whitaker test (Whitaker test).
• Retrograde pyelography (Retrograde Pyelogram). Performed by a urologist in the operating room. Contrast medium is injected from bottom to top via a catheter or flexible ureteroscope placed in the ureteral orifice.
• Nephrostomy (Nephrostomy). The procedure of placing a drainage tube (pigtail or J-J catheters) into the dilated renal pelvis. Puncture of the lower calyx is performed under dual guidance (ultrasound and fluoroscopy). Potential complications include urine leakage, contrast extravasation, and tube displacement.

Congenital renal anomalies

Embryologically, the kidney forms in the 4th week of gestation through the interaction of the ureteric bud and the metanephros. During development, the organ ascends and rotates by 90 degrees. Disruptions of this mechanism lead to various anomalies:

1. Agenesis (Renal Agenesis). Complete absence of a kidney, which may result from the involution of multicystic dysplastic kidney. It is often accompanied by vesicoureteral reflux and ipsilateral anomalies of the reproductive system (uterus, seminal vesicles).
2. Ectopia (Renal Ectopia). Abnormal location of the organ due to incomplete or excessive ascent. The most common variant is pelvic dystopia (below the aortic bifurcation). Intrathoracic and upper ectopias are less common. Notably, the adrenal glands usually remain in their normal anatomical position.
3. Fusion anomalies. Occur when the kidneys touch during ascent. A typical example is the horseshoe kidney (horseshoe kidney), in which the lower poles fuse in the midline. The isthmus is located anterior to the aorta at the level of the inferior mesenteric artery. Due to malrotation of the collecting systems, such patients are predisposed to pelviureteric junction obstruction, infections, and stone formation.

Oncourology: CT diagnosis and treatment monitoring

Accurate diagnostic imaging is critical for surgical planning. For instance, in hematuria, it is important to differentiate transitional cell carcinoma (Transitional cell tumour) from renal cell carcinoma. Urothelial carcinoma is characterized by a central endophytic mass that shows minimal contrast enhancement. Confirmation of this diagnosis requires the removal of both the kidney and the ureter.

Following local treatment (e.g., cryotherapy), careful monitoring is required:

• Normal: the intervention zone undergoes involution, and residual soft tissue in the center does not enhance with contrast and is surrounded by stranding paranephric fat.
• Recurrence: the appearance of new tissue on the medial or lateral surface of the kidney that actively enhances with contrast.

Role of biopsy and histology

Morphological verification is the gold standard for diagnosis. In urology, biopsies of the kidney (most commonly percutaneous under ultrasound guidance), prostate, and bladder are used. If puncture is contraindicated, open surgical intervention may be required. Rare complications of the puncture include subcapsular hematoma and arteriovenous fistula.

Histological examination serves several purposes simultaneously:

• Assessment of disease activity: for example, in glomerulonephritis, light microscopy, electron microscopy, and immunofluorescence with specific stains (PAS reaction, Masson's trichrome, silver impregnation) are used.
• Intraoperative navigation: urgent cryostat biopsy allows the surgeon to determine the nature of the tumor within 15–20 minutes and adjust the scope of surgery.
• Molecular genetic analysis: detecting specific mutations (e.g., 1p/19q translocation) in the biopsy specimen helps select targeted therapy.

Class and exam questions

What else to study on this topic

• Complications of nephrostomy placement: extravasation and catheter misplacement
• Use of 99mTc-DMSA scintigraphy to assess renal function
• Ultrasound signs of a horseshoe kidney: using an acoustic window
• Histological fibrosis scoring systems (Knodell, Ishak, METAVIR)
• Specific staining of microsections in the diagnosis of glomerulonephritis

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.