Comparison of Temporary Drainage Techniques

Despite limited options, the method for urgent decompression of the obstructed urinary tract is controversial. Proponents of percutaneous nephrostomy suggest that drainage is improved with the larger sized nephro-stomy tube and that complications related to manipulation of a stent across the area of blockage are eliminated (i.e., ureteral perforation). In addition, percutaneous nephrostomy can be performed under local anesthesia, which is a true benefit for many patients. In some institutions where percutaneous nephrostomy tubes are placed by interventional radiologists, a time delay can be associated with use of this drainage technique. To facilitate expeditious treatment, advocates of retrograde stent placement suggest that this drainage technique can be performed more quickly and is less invasive (Pe-arle et al. 1998).

For patients with normal upper urinary tracts, Pear-le and colleagues compared the efficacy of percutaneous nephrostomy vs retrograde catheterization in cases of obstruction and infection associated with ureteral stones (Pearle et al. 1998). Among 42 consecutive patients with obstructing ureteral stones, patients were randomized into percutaneous or retrograde drainage. Mean operative time (32.7 min vs 49.2 min) and fluoroscopy time (5.1 min vs 7.7 min) were significantly lower among the patients drained via retrograde catheter placement. One patient failed drainage in the percutaneous treatment group and was salvaged with retrograde stent placement. When comparing percutaneous nephrostomy tube placement to retrograde stenting, no significant differences were observed in time to treatment, time to normal temperature (2.3 days vs 2.6 days), time to normal white blood cell count (2 days vs 1.7 days), or length of hospitalization (4.5 days vs 3.2 days). Nonetheless, a twofold cost advantage was realized for percutaneous nephrostomy tube placement in comparison to retrograde stent placement. The authors concluded that neither technique was superior. They recommended that selection of the drainage modality must be made on the basis of the surgeon's preference, logistic factors, and stone characteristics.

On the other hand, Mokhmalji and co-workers reported a prospective randomized comparison of per cutaneous nephrostomy tube placement vs ureteral stent placement for obstructing stones (Mokhmalji et al. 2001). In this evaluation of 40 stone patients, percutaneous nephrostomy tube placement was successful in 100% of cases, while ureteral stent placement was successful in 80 % of cases. In contrast to the report by Pe-arle and colleagues, the authors noted that analgesic use was more common and quality of life reduced in patients undergoing stent placement. In addition, the reduction in quality of life was most pronounced in men and younger patients within the retrograde stent placement group. Based on their data, the authors recommended percutaneous nephrostomy tube placement as the drainage procedure of choice with obstructed stones.

In another attempt to optimize choice of emergent drainage procedures, Yossepowitch and associates evaluated risk factors for retrograde stent placement in a group of 92 consecutive patients with ureteral obstruction (Yossepowitch et al. 2001). Among patients within-trinsic and extrinsic ureteral obstructions, stenting was initially successful in 94% and 73% of patients, respectively. At 3-month follow-up, however, the success rate was constant in all intrinsic obstruction patients but decreased to 56 % in the extrinsic obstruction patients. In a multivariate analysis of failure, extrinsic ureteral obstructions with more significant hydronephrosis and a more distal level of obstruction were more common to fail retrograde stent placement regardless of stent diameter. The authors suggested based on their analysis that percutaneous nephrostomy tube placement may be superior in this subset of patients.

Among 101 patients with extrinsic ureteral obstruction, Chung and colleagues evaluated their 15-year experience with retrograde ureteral stenting (Chung et al. 2004). The etiology of extrinsic obstruction was metastatic cancer in 89% (90/101 patients) and at a mean followup of 5.8 months after stenting, 32.2% of these patients had died. Overall, stent failure occurred in 58 renal units. For 40 renal units, salvage percutaneous nephrostomy tubes were placed at a mean follow-up of 40 days. In 18 of the 40 renal units, a nephrostomy tube was placed as salvage therapy less than 1 week from retrograde stenting. In the remaining renal units not salvaged by nephrostomy tube placement, the mean time to failure was 52.4 days. In a multivariate analysis model, the following factors were suggestive of retrograde stent failure: diagnosis of cancer, baseline renal insufficiency, and metastatic disease requiring chemotherapy or radiation therapy.

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