Case of the Month January 2014, page 5

ANSWER: The incidence of catheter dislodgment in the first month after placement is approximately 1%.

Nephrostomy tube insertion:

INDICATIONS:

Specific indications for percutaneous nephrostomy include the following:
• Acute or chronic upper urinary tract obstruction
• When a patient's creatinine level is rising above the reference range and the urine cannot be drained through the ureter
• Renal pelvis disorders (eg, UPJ obstruction, horseshoe kidneys, ureter duplex, ureter fissures, double renal collecting systems)
• Hydronephrosis in renal transplant allografts
• Treatment of staghorn calculi and large or lower-pole kidney stones
• Stones or tumors associated with distal obstruction
• When rapid dilation of the nephrostomy tract is required, eg, when access is needed instantly for operative procedures within the renal collecting system.

TECHNIQUE:

Puncture site selection is crucial for minimizing the risk of hemorrhage. The best route for needle entry into the renal collecting system is via an oblique posterolateral approach along the Brodel 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 Brodel 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 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 the stylet is removed, and urine is returned if an obstruction is present.

Once access into the collecting system has been obtained, successful wire exchanges should continue until a 0.035-in. J-tip wire is placed into the renal pelvis or down the ureter. The tract should then be dilated with polytetrafluoroethylene dilators (some authors have used metal dilators or cutting balloon). The drainage catheter should be flushed, and the trocar 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 trocar should be loosened, and the catheter should be slipped 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.

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.

COMPLICATIONS:

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%)
• 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%)


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