Percutaneous Nephrostomy Technique

After appropriate patient preparation (see Periprocedural Care), a small skin nick is made at the puncture site to facilitate passage of the needle into the skin.

Puncture site selection is crucial for minimizing the risk of hemorrhage. ^[13] The best route for needle entry into the renal collecting system is via an oblique posterolateral approach along the Brödel line into the end of a posterior calyx. This line is near the posterior axillary line and is about 2-3 cm below the 12th rib. A percutaneous nephrostomy tract that approaches along the Brödel line is associated with the smallest risk of substantial arterial injury and subsequent hemorrhage.

The needle (22 or 21 gauge) is angled toward a posterior lower-pole or middle-pole calyx under ultrasonographic guidance. If the collecting system is not dilated, intravenous (IV) administration of contrast medium may be required to achieve adequate visualization of the target. Once the needle is inserted into the calyx and into the collecting system (see the image below), the stylet is removed, and urine is returned if an obstruction is present.

If no urine is present, there are a few maneuvers that may be tried. A 10-mL syringe should be attached to the needle hub, and the needle and syringe should be retracted slightly. If urine is aspirated, the tip is probably within the collecting system.

Otherwise, a 0.018-in platinum-tipped wire (see the image below) may be used to probe the region, or a small amount of contrast agent may be injected to check the positioning. Injection of 10 mL of medical-grade carbon dioxide or room air may be done to confirm that the needle is positioned in the posterior calyx. With the patient in the prone position, the posterior calyces will be filled with the gas, whereas the anterior calyces will be filled with the contrast agent.

After the collecting system has been accessed, a urine sample may be obtained and sent for routine culture and sensitivity testing. Contrast material should be gently injected into the collecting system to confirm the location. Overdistention of the system with contrast material or withdrawal of too much urine for culture should be avoided because these can cause bacterial seeding or render access difficult if the wire is inadvertently lost. As a rule, the amount of contrast agent used for injection is equal to the amount of urine removed.

Once access into the collecting system has been obtained, over the wire introducer exchanges are continued until a 0.035-in. wire can be placed into the renal pelvis or down the ureter. The tract should then be dilated with polytetrafluoroethylene dilators (some authors have used metal dilators ^{[14, 15]} or cutting balloons ^[16] ). The drainage catheter should be flushed, and the metal stiffener that comes with the kit should be inserted.

The catheter should be advanced into the proximal renal parenchyma over the 0.035-in. guide wire, the metal stiffener should be loosened, and the catheter advanced off the trocar and into the renal pelvis. The internal wire should be pulled to lock the pigtail catheter, and the catheter should be seated appropriately within the renal pelvis (see the image below).

The position of the catheter should be confirmed with the use of contrast material, and the catheter should be tied to the skin with suture (2-0 silk or 2-0 polypropylene) and attached to an external drainage bag. ^[17]

In a retrospective study of 333 patients who underwent a percutaneous nephrolithotomy using a retrograde technique, stone clearance and complication rates were comparable to percutaneous nephrolithotomy with antegrade access. ^[18]

A study by Cui et al indicated that intracavitary contrast-enhanced ultrasonography (ICCEUS) can be effectively used to guide percutaneous nephrostomy. All 45 of the study’s percutaneous nephrostomies were successfully carried out (on 35 patients total) using this imaging modality, with correct insertion of the needle and catheter confirmed through ICCEUS and the obstruction located in all cases. In addition, using ultrasonographic contrast agent, catheter dislodgement was diagnosed in five patients. ^[19]

Major complications with percutaneous nephrostomy tube placement include the following:

• Bleeding

• Sepsis

• Injury to an adjacent organ

Other major complications, though somewhat rare, have been reported to occur in as many as 5% of patients. Complications of percutaneous nephrostomy and their frequencies are as follows:

• Massive hemorrhage requiring transfusion, surgery, or embolization (1-3%) ^[20]

• Pneumothorax (< 1%)

• Microscopic hematuria (common)

• Pain (common)

• Extravasation of urine (< 2%)

• Inability to remove the nephrostomy tube because of crystallization around the tube site

• Death (0.2%)

• Sepsis (1.3%)

• Catheter dislodgement during the first month (< 1%)

Misra and colleagues undertook a detailed retrospective case review to assess survival and complication rates of 36 patients who underwent percutaneous nephrostomy for ureteric obstruction due to pelvic malignancy. Median survival was 78 days (range 4-1,137), with dislodgement of the nephrostomy tube the most common serious complication which led to the greatest morbidity, sometimes requiring repeat nephrostomy insertion. With a median of hospital stay of 23 (range 3-89) days, 29 % of their remaining lifetime was spent in hospital. Because percutaneous nephrostomy in patients with advanced pelvic malignancy does not always prolong life, and is associated with serious complications, the researchers recommend the decision to undergo the procedure must be include a full informed discussion with the patient and their family. ^[21]