**3. Surgical approach**

Nephrostomy can be performed either by open operation or by closed percutaneous methods. With the development of endourologic and imaging techniques, percutaneous nephrostomy is widely used. Recently, the percutaneous nephrostomy placement became the standard of care, replacing surgical nephrostomy. (Banner et al., 1991 & Sherman et al., 1985)

Establishing safe and reliable nephrostomy tract is very important. The aim of the nephrostomy tract ranges from simple urinary drainage to intrarenal surgical operation. For percutaneous renal surgeries, some surgeons prefer a two stage surgery which can limit bleeding, provide a clear field and let the nephrostomy tract mature.

A successful outcome without complications is the goal of this procedure, which requires careful preoperative planning and proper techniques. The preoperative anatomy of the patient, the nature of the urologic procedure planned and available equipment are very important.

#### **3.1 Open nephrostomy technique**

Explore the kidney and open the renal pelvis and choose the calix which is suitable for nephrostomy. The catheter is introduced through thinned cortex into the renal pelvis.

#### **3.2 Percutaneous nephrostomy techniques**

### **3.2.1 Preoperative patient preparation**

All patients need appropriate hemostasis evaluation and urine bacteriologic assessment. Careful review and assessment of the degree of hydronephrosis, anatomic variance of the pelvicaliceal system, and relative position of the kidney are key factors for success and will reduce any potential complication of nephrostomy tube placement. This can be evaluated by previous or currents plain Kidney-Urinary–Bladder (KUB) radiography, intravenous pyelography, retrograde pyelography, computed tomogram and ultrasonographic studies. These radiographic investigations demonstrate size, number and location of renal and ureteral calculi as well as establishing baseline renal function and other pathology.

The evaluation of choice to detect urolithiasis and intraabdominal anatomy in patients with emergent or complex medical conditions is a computer tomography (CT scan) of the whole abdomen. Pre-nephrostomy placement with CT scan is recommended in selected patients with splenomegaly, colonic malposition and marked colonic distention. (LeRoy., 1996)

Patients who have urinary tract infection are treated with bacteriologically specific antibiotics and these patients need parenteral antibiotics for 36 to 48 hours before surgery to ensure adequate serum levels of effective antibiotics. The recommended regimen is ciprofloxacin 400 mg IV every 12 hr, ampicillin 1 gm IV every 6 hr with gentamicin 1 mg/kg every 8 hr or third generation cephalosporin.

Laboratory testing of any bleeding problem such as PT, PTT (Prothrombin time, Partial thromboplastin time) and platelet count should be done with appropriate adjustments especially in patients with a history of prolonged bleeding, liver disease, clinically easy brusisability or other conditions predisposing to a coagulopathy. A platelet count should be above 80,000 cells per ml prior to the procedure. Aspirin therapy should be discontinued 1 week prior to the procedure. Caumadin as an anticoagulants must be discontinued. Subcutaneous heparin can be administered for high risk patients with venous thrombosis.
