Metallic Ureteral Stents Found Superior

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BARCELONA—A thermo-expandable segmental metallic stent has scored higher than a conventional polyurethane plastic stent on a validated quality of life questionnaire completed by patients with ureteral strictures, a British group reported at the 25th Anniversary European Association of Urology Congress.

The researchers, from Barts and the London NHS Trust, found that the newer metal stent was significantly better than the plastic stent on most components of the ureteral stent symptom questionnaire (USSQ).  The USSQ is a widely validated, self-administered questionnaire that evaluates stent-related morbidity with respect to urinary symptoms, body pain, general health, work performance, sexual matters, and additional problems.

“The newer stent produces a better quality of life because it is associated with fewer complications,” said co-investigator Konstantinos Moraitis, MD, a senior endourology fellow.

Stents have revolutionized the minimally invasive management of malignant and benign ureteral strictures, especially in high-risk patients, he explained. Plastic stents, however, are limited by a range of side effects, including encrustration (necessitating frequent replacement), stone formation, pain, reflux, decreased ureteral peristalsis, and migration.

Metal segmental stents have been developed to address some of the limitations of plastic stents. The metallic stent used in the present study is a permanent thermo-expandable nickel-titanium alloy, segmental ureteric stent.

In the study, 41 of 70 patients completed the USSQ questionnaire four weeks after stent insertion. Overall, 23 patients had a conventional plastic stent implanted and 18 had a metallic stent. Ten patients underwent insertion of both types of stents and thus completed two questionnaires.

Results showed that urine frequency (defined as urination within two hours) was significantly less common with the metallic stent. “Notably, nearly 70% of patients who received conventional stents reported this symptom versus 47% of patients implanted with a metallic stent,” he said.

Significantly more patients with the plastic stent than the metallic stent said that they were extremely bothered by urinary symptoms (31.8% vs. 5.6%).

In addition, about two thirds of patients with the plastic stent said they were pessimistic about the prospect of living with their current urinary symptoms compared with only one third of patients with the metallic stent.

Metallic stents also performed significantly better on the domains of stent- related pain and the ability to perform light and heavy activity. Patients said they preferred metallic stents for future stent insertion.

Dr. Moraitis pointed out that the metallic stent may cause fewer symptoms because it remains tightly positioned within the ureter, meaning that stent ends are not needed. For this reason, it does not protrude into the bladder or the renal pelvis, which means patients have significantly fewer lower urinary tract symptoms such as urinary frequency, nocturia, and hematuria, and also less low inguinal groin pain, he said.

More importantly, however, the metallic stent does not require frequent routine exchange. “Conventional stents have to be replaced at least every six months, and the metallic stent we used in this study has lasted as long as five years,” he noted.

Stent tolerability and its impact on quality of life is an important patient priority, Dr. Moraitis said.  In fact, research has shown that patients whose stent-related problems are significant may not be able to work or perform routine activities and they may be at increased risk of depression.

Importantly, he pointed out that the metallic stent should be reserved for patients with malignant or benign ureteric strictures and not used in patients with stone disease.

Finally, he acknowledged that the results are limited by the small sample size. Plans are underway for a larger, multicenter trial to compare stent-related symptoms with the two stents.

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