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H K Mardis

Publications and source records attributed to H K Mardis.

11 recordsLinked to original sources

Comparative evaluation of materials used for internal ureteral stents.

The materials used in the fabrication of self-retained internal ureteral stents should provide strength, flexibility, low surface friction, radiopacity, biodurability, biocompatibility, and reasonable unit cost. Polymeric biomaterials currently used for stent construction include polyurethane, silicone, Silitek, C-Flex, and Percuflex. Comparative evaluation of these materials in the context of the requirements for stent structure and function suggests advantages and disadvantages for all of them. We believe that the most important attributes for an internal ureteral stent are ease of insertion, effective restoration and maintenance of flow, resistance to migration, significant biodurability, and biocompatibility. Based on our physical testing of stents fabricated from these materials, as well as clinical and laboratory experience, we believe that C-Flex and Percuflex are the most suitable materials for stent construction.

Biocompatible Materials

Ureteral stents. Materials.

There is no "ideal" ureteral stent material at this time, yet these devices are very useful endourologic tools. One can utilize the physical data presented herein, as well as personal preference and experience, to select a stent best suited for the problem presented by the patient. The hydrogels, a new class of ureteral stent material, promise to enhance the applicability and utility of the self-retained internal ureteral stent.

Biocompatible Materials

Double pigtail ureteral stent.

Problems encountered in patients with ureteral obstruction treated with single pigtail polyethylene ureteral catheters (stents) were largely due to positioning difficulties, proximal migration, and irritation of the bladder mucosa by the distal flange. A new, double pigtail modification of this self-retained internal stent limits migration, minimizes irritant side effects, and facilitates endoscopic, percutaneous, and open surgical positioning over a springwire guide. These stents provide useful alternative to surgical correction or external tube diversion in many patients with complicated ureteral obstruction.

Humans

The pigtail ureteral stent in the cancer patient.

Nephrostomy has been the standard procedure for urinary diversion when ureters are obstructed by cancer. However, recent reports have revealed significant problems related directly to the nephrostomy. The indwelling, internal ureteral stent eliminates many of these problems. We herein describe the course and survival of 20 patients in whom the pigtail ureteral stent was used to relieve ureteral obstruction caused by cancer. In these cases an over-all prolonged longevity, better quality of life and fewer complications have been noted when compared to cases of nephrostomy diversions.

Adult

Self-retained internal ureteral stents: a new approach.

Definitive surgical treatment of ureteral obstruction may not be appropriate in patients with advanced malignancy, complex benign ureteral disease or even simple obstructive disease accompanied by unacceptable operative risk. Endoscopic placement of self-retained internal ureteral catheters (stents) offers satisfactory relief for many of these patients. A new 6F pigtail ureteral stent and placement technique are described. These stents are placed easily, effective and well tolerated for short-term drainage in selected patients with ureteral obstruction.

Aged