The efficacy of metallic stent placement in the treatment of colorectal obstruction

Abstract

Objective: To evaluate the efficacy of newly designed covered and non-covered coated colorectal stents for colonic decompression.

Materials and methods: Twenty-six patients, (15 palliative cases and 11 preoperative) underwent treatment for the relief of colorectal obstruction using metallic stents positioned under fluoroscopic guidance. In 24 of the 26, primary colorectal carcinoma was diagnosed, and in the remaining two, recurrent colorectal carcinoma. Twenty-one patients were randomly selected to receive either a type A or type B stent; for the remaining five, type C was used. Type A, an uncovered nitinol wire stent, was lightly coated to ensure structural integrity. Type B (flare type) and C (shoulder type) stents were polyurethane covered and their diameter was 24 and 26 mm, respectively. The rates of technical success, clinical success, and complications were analyzed using the chi-square test, and to analyse the mean period of patency, the Kaplan-Meier method was used.

Results: Thirty of 31 attempted placements in 26 patients were successful, with a technical success rate of 96.8% (30/31) and a clinical success rate of 80.0% (24/30). After clinically successful stent placement, bowel decompression occurred within 1-4 (mean, 1.58+/-0.9) days. Five of six clinical failures involved stent migration and one stent did not expand after successful placement. In the preoperative group, 11 stents, one of which migrated, were placed in ten patients, in all of whom bowel preparation was successful. In the palliative group, 19 stents were placed in 15 patients. The mean period of patency was 96.25+/-105.12 days: 146.25+/-112.93 for type-A, 78.82+/-112.26 for type-B, and 94.25+/-84.21 for type-C. Complications associated with this procedure were migration (n=6, 20%), pain (n=4, 13.3%), minor bleeding (n=5, 16.7%), incomplete expansion (n=1, 3.3%), and tumor ingrowth (n=1, 3.3%). The migration rate was significantly higher in the type-B group than in other groups (p=0.038).

Conclusion: Newly designed covered and non-covered metallic stents of a larger diameter are effective for the treatment of colorectal obstruction. The migration rate of covered stents with flaring is higher than that of other types. For evaluation of the ideal stent configuration for the relief of colorectal obstruction, a clinical study involving a larger patient group is warranted.

Fig. 1

A. Three types of colorectal stent: type A (upper), type B (middle), and type C (lower). B. The drawstring. Each bend of each segment contains a 2-mm-diameter nylon monofilament loop secured with sutures (thin arrow). These loops form the anchor for another nylon thread which is passed through each of them to form a large loop or drawstring (thick arrow) that fills the inner circumference of the inside of the proximal stent. The resultant loop is then tied at the stent's upper inner margin.

Fig. 2

Type-A stent placement for presurgical bowel preparation (patient #10). A. Irregular narrowing of the proximal rectum (arrow) is apparent. B. Although focal narrowing remains, good passage of contrast medium is observed after type-A stent placement. Four days after placement, this patient underwent anastomosis and tumor resection.

Fig. 3

Type-B stent placement for palliation (patient #8). A. Irregular narrowing of the rectosigmoid colon (arrow) can be seen. B. After type-B stent placement, good patency is observed (arrow). In this patient, symptoms of obstruction recurred 180 days after placement, and a palliative ileostomy was performed.

Fig. 4

Type-C stent placement inside a type-A stent (patient #21). A. Tumor ingrowth, which developed four months after stent placement, was confirmed by endoscopy. B. Guidewire advanced through previously placed type-A stent. C. Deployment of type-C stent (arrow), which is longer than type A (arrowheads). D. The type-C stent showed good patency and was patent for three months, until the patient's death.