Colon stenting: a review

Gastrointestinal devices: common and uncommon foreign bodies

Devices for the gastrointestinal tract are widely available and constantly advancing with less invasive techniques. They play a crucial role in diagnostic and therapeutic interventions and are commonly placed by interventional radiologists, gastroenterologists, and surgeons. These devices frequently appear in imaging studies, which verify their proper placement, identify any complications, or may be incidentally detected. Radiologists must be able to identify these devices at imaging and understand their intended purpose to assess their efficacy, detect complications such as incorrect positioning, and avoid misinterpreting them as abnormalities. Furthermore, many patients with these devices may require MRI, making assessing compatibility essential for safe patient care. This review seeks to provide a succinct and practical handbook for radiologists regarding both common and uncommon gastrointestinal devices. In addition to textual descriptions of clinical indications, imaging findings, complications, and MRI compatibility, the review incorporates a summary table as a quick reference point for key information and illustrative images for each device.

Endoscope-Assisted Traversal of a Ureteral Stricture From Percutaneous Nephrostomy Access

Interventional radiology-operated endoscopy has a small but growing number of applications. In this clinical case report, we describe the use of an endoscope to assist the traversal of a high-grade ureteral stricture from percutaneous nephrostomy (i.e., antegrade) access. Direct visualization of the stricture allowed the identification of a central channel that was not present in fluoroscopic images, making endoscopy essential to the technical success of the procedure. Endoscopy is a powerful adjunct to image-guided techniques, particularly in challenging interventions or cases with complex anatomy.

Colonic stent as a bridge to surgery versus emergency resection for right-sided malignant large bowel obstruction: a meta-analysis

BACKGROUND

Preoperative colonic stenting for malignant large bowel obstruction (MLBO), also called bridge to surgery (BTS), is considered a great substitute treatment for emergency resection (ER) in the left-sided colon. However, its efficacy in the right-sided colon remains controversial. This systematic review and meta-analysis aimed to compare the postoperative short-term outcomes between BTS and ER for right-sided MLBO.

METHODS

A comprehensive electronic literature search throughout December 2020 was performed to identify studies comparing short-term outcomes between BTS and ER for right-side MLBO. The main outcome measures were postoperative complications and mortality rates. A meta-analysis was performed using a fixed-effect or a random-effect method to calculate odds ratios (ORs) with 95% confidence intervals (95% CIs).

RESULTS

Seven studies were included in this meta-analysis, comprising 5136 patients, of whom 1662 (32.4%) underwent BTS and 3474 (67.6%) underwent ER. This meta-analysis demonstrated that BTS resulted in reductions in postoperative complications (OR = 0.78; 95% CI: 0.66-0.92) and mortality (OR = 0.51; 95% CI: 0.28-0.92) than ER.

CONCLUSION

The results of this meta-analysis indicate that BTS for right-sided MLBO confers preferable short-term outcomes as well as for left-sided. This suggests that BTS results in a reduction of postoperative complications and mortality for right-sided MLBO than ER.

Imaging Modalities for Evaluation of Intestinal Obstruction

It is essential for the colon and rectal surgeon to understand the evaluation and management of patients with both small and large bowel obstructions. Computed tomography is usually the most appropriate and accurate diagnostic imaging modality for most suspected bowel obstructions. Additional commonly used imaging modalities include plain radiographs and contrast imaging/fluoroscopy, while less commonly utilized imaging modalities include ultrasonography and magnetic resonance imaging. Regardless of the imaging modality used, interpretation of imaging should involve a systematic, methodological approach to ensure diagnostic accuracy.

Obstructing Left-Sided Colonic Cancer: Is Endoscopic Stenting a Bridge to Surgery or a Bridge to Nowhere?

For the 8-29% colorectal cancers that initially manifest with obstruction, emergency surgery (ES) was traditionally considered the only available therapy, despite high morbidity and mortality rates and the need for colostomy creation. More recently, malignant obstruction of the left colon can be temporized by endoscopic placement of a self-expanding metallic stent (SEMS), used as bridge to surgery (BTS), facilitating a laparoscopic approach and increasing the likelihood that a primary anastomosis instead of stoma would be used. Despite these attractive outcomes, the superiority of the BTS approach is not clearly established. Few authors have stressed the potential cancer risk associated with perforations that may occur during endoscopic stent placement, facilitating neoplastic spread and negatively impacting prognosis. For this reason, the current literature focuses on long-term oncologic outcomes such as disease-free survival, overall survival and recurrence rate that do seem not to differ between the ES and BTS approaches. This lack of consensus has spawned differing and sometimes discordant guidelines worldwide. In conclusion, 20 years after the first description of a colonic stent as BTS, the debate is still open, but the growing number of articles about the use of SEMS as a BTS signifies a great interest in the topic. We hope that these data will finally converge on a single set of recommendations supporting a management strategy with well-demonstrated superiority.

Beyond the Bile Duct: Advanced IR Endoscopic Interventions Involving the Gastrointestinal, Genitourinary, and Musculoskeletal Systems

Endoscopy is a technique used by interventional radiology (IR) in only a few centers throughout the United States. When used by IR, endoscopy is most well-known for its role in the treatment of hepatobiliary disease. However, its use with relation to pathology involving the gastrointestinal, genitourinary, and musculoskeletal systems is gaining momentum among IR. The purpose of this article is to demonstrate the potential benefits of IR endoscopy in nonbiliary intervention. A literature review, not requiring IRB approval, was performed via PubMed and Ovid Medline databases using the search terms "interventional radiology-operated endoscopy," "interventional endoscopy," "interventional radiology," "genitourinary," and "gastrointestinal." Literature describing IR endoscopy involving the gastrointestinal, genitourinary, and musculoskeletal systems were identified and described. Nine peer-reviewed articles were identified. While few studies were identified, a general theme suggesting a synergistic relationship between IR and endoscopy was noted. More studies are needed to better understand the role of endoscopy as a technique in the IR suite.

Endoscopy as an Adjunct to Image-Guided Interventions: A New Frontier in Interventional Radiology

Endoscopy is an underutilized technique in the practice of interventional radiology. The objectives of this article are to discuss potential uses of interventional radiology-operated endoscopy and to outline basic endoscopy setup and equipment uses. Endoscopy represents a new frontier to the fluoroscopically-guided procedures in biliary, gastrointestinal, and genitourinary disease that interventional radiologists commonly perform. It shows promise to improve interventional radiology procedure success rates and reduce procedure-associated risk for patients. Endoscopy has been traditionally performed by gastroenterologists and urologists and is relatively new in the practice of interventional radiology. The hand-eye coordination and manual dexterity required to perform standard image-guided procedures places interventional radiologists in a unique position to introduce endoscopy into standard practice. A focused and collaborative effort is needed by interventional radiologists to learn the techniques required to successfully integrate endoscopy into practice.

Management of Colorectal Cancer Patients Undergoing a Colonic Stenting: A Multidisciplinary Team Approach

Colonic stent procedure is one of the best therapeutic medical interventions for managing a colorectal cancer patient with large bowel obstruction. This is a retrospective study that evaluated data from the past 10 years; it examined the epidemiological and clinical data of patients with colorectal cancer undergoing a colonic stent procedure. In addition, this study prospectively evaluated the nurse's roles during a colonic stent procedure, and at the same time, it explored the patient's satisfaction with the procedure at the Hospital Universitario Central de Asturias (Spain). The results revealed that for the last 10 years, a total of 102 patients underwent a colonic stent procedure. Male patients outnumbered female patients by 2:1. The palliative group consisted of patients with multiple cancer metastases, elderly patients, and patients with other comorbidities, whereas the preoperative group comprised those patients with fewer comorbidities and no multiple cancer metastases. Survival time in the palliative group was 3 months without any aggressive treatment, whereas patients with a favorable condition and fit for surgery after a colonic stent procedure had a survival time of 28 months. In the prospective study, nurses implemented care in terms of a multidisciplinary team approach of safety culture that included patient safety, equipment safety, and environment and procedure safety. Therefore, the level of patient satisfaction was high. In conclusion, management of a colorectal cancer patient undergoing colonic stenting performed at the Hospital Universitario Central de Asturias has high technical and clinical success, and it is a quality procedure that includes a multidisciplinary team approach.

Interventional Radiology-Operated Endoscopy as an Adjunct to Image-Guided Interventions

PURPOSE

Interventional radiology-operated endoscopy is an underused technique, which may have a significant impact on the ability to treat patients with a variety of conditions. The purpose of this article is to discuss the setup, equipment, and potential clinical uses of interventional radiology-operated endoscopy.

METHODS

A number of new and innovative interventions may be performed in the biliary, genitourinary, and gastrointestinal systems through percutaneous access that interventional radiologists already create. When used in combination, endoscopy adds an entirely new dimension to the fluoroscopic-guided procedures of which interventional radiologists are accustomed.

RESULTS

Interventional radiologists are in a unique position to implement endoscopy into routine practice given the manual dexterity and hand-eye coordination already required to perform other image-guided interventions.

CONCLUSION

Although other specialists traditionally have performed endoscopic interventions and local politics often dictate referral patterns, a collaborative relationship among these specialists and interventional radiology will allow for improved patient care. A concerted effort is needed by interventional radiologists to learn the techniques and equipment required to successfully incorporate endoscopy into practice.

Complementary roles of interventional radiology and therapeutic endoscopy in gastroenterology

Acute upper and lower gastrointestinal bleeding, enteral feeding, cecostomy tubes and luminal strictures are some of the common reasons for gastroenterology service. While surgery was initially considered the main treatment modality, the advent of both therapeutic endoscopy and interventional radiology have resulted in the paradigm shift in the management of these conditions. In this paper, we discuss the patient’s work up, indications, and complementary roles of endoscopic and angiographic management in the settings of gastrointestinal bleeding, enteral feeding, cecostomy tube placement and luminal strictures. These conditions often require multidisciplinary approaches involving a team of interventional radiologists, gastroenterologists and surgeons. Further, the authors also aim to describe how the fields of interventional radiology and gastrointestinal endoscopy are overlapping and complementary in the management of these complex conditions.

Management of colon stents based on Bernoulli's principle

BACKGROUND AND AIMS

The colonic self-expanding metal stent (SEMS) has been widely used for "bridge to surgery" and palliative therapy. However, if the spread of SEMS is insufficient, not only can a decompression effect not be obtained but also perforation and obstructive colitis can occur. The mechanism of occurrence of obstructive colitis and perforation was investigated by flow dynamics.

METHODS

Bernoulli's principle was applied, assuming that the cause of inflammation and perforation represented the pressure difference in the proximal lumen and stent. The variables considered were proximal lumen diameter, stent lumen diameter, flow rate into the proximal lumen, and fluid density. To model the right colon, the proximal lumen diameter was set at 50 mm. To model the left-side colon, the proximal lumen diameter was set at 30 mm.

RESULTS

For both the right colon model and the left-side colon model, the difference in pressure between the proximal lumen and the stent was less than 20 mmHg, when the diameter of the stent lumen was 14 mm or more. Both the right colon model and the left-side colon model were 30 mmHg or more at 200 mL s^-1 when the stent lumen was 10 mm or less. Even with an inflow rate of 90-110 mL s^-1, the pressure was 140 mmHg when the stent lumen diameter was 5 mm.

CONCLUSION

In theory, in order to maintain the effectiveness of SEMS, it is necessary to keep the diameter of the stent lumen at 14 mm or more.

A novel, ring-connected stent versus conventional GI stents: comparative study of physical properties and migration rates in a canine colon obstruction model

BACKGROUND

Migration of stents is one of the most common adverse events in covered stent placement in GI tract obstruction.

OBJECTIVE

To compare physical property and migration rates in a canine colon obstruction model among a novel stent and conventional stents.

DESIGN

Comparative physical test and animal study.

SETTING

Medical device testing laboratory and animal laboratory.

SUBJECTS

Mongrel dogs (N=26).

INTERVENTIONS

Surgical colon obstruction followed by placement of a novel (n=13) or conventional (n=13) stent.

MAIN OUTCOME MEASUREMENTS

Physical properties, migration, and adverse events.

RESULTS

The novel stent showed better flexibility, as in a physical test of longitudinal compressibility and axial force, than did conventional stents, and it withstood the fatigue test for 10 days. In terms of radial force and tensile strength, the novel stent showed the same or better results than conventional stents. In a canine colon obstruction model, the migration rate of a novel stent was significantly lower than that of a conventional stent (2/13, 15.4% vs 8/13, 61.5%; P=.008).

LIMITATIONS

Animal study of limited size.

CONCLUSION

The novel, ring-connected stent is more flexible and more resistant to migration than the conventional stents.

Self-expanding metallic stents for palliation and as a bridge to minimally invasive surgery in colorectal obstruction

Self-expanding metallic stents are effective for the palliation of malignant obstruction. This study indicates that stents for bowel obstruction may allow for minimally invasive surgical intervention with a shorter hospital stay, lower stoma rate, and earlier chemotherapy administration.

Background and Objectives:

Acute colorectal obstruction is a potentially life-threatening emergency that requires immediate surgical treatment. Emergency procedures had an associated mortality rate of 10% to 30%. This encouraged development of other options, most notably self-expanding metallic stents. The primary endpoint of this study to is to report our group's experience.

Methods:

We performed a retrospective review of 37 patients who underwent self-expanding metallic stent placement for colorectal obstruction between July 2000 and May 2012. Data collected were age, comorbidities, diagnosis, intent of intervention (palliative vs bridge to surgery), complications, and follow-up.

Results:

The study comprised 21 men (56.76%) and 16 women (43.24%), with a mean age of 67 years. The intent of the procedure was definitive treatment in 22 patients (59.46%) and bridge to surgery in 15 (40.54%). The highest technical success rate was at the rectosigmoid junction (100%). The causes of technical failure were inability of the guidewire to traverse the stricture and bowel perforation related to stenting. The mean follow-up period was 9.67 months. Pain and constipation were the most common postprocedure complications.

Discussion:

The use of a self-expanding metallic stent has been shown to be effective for palliation of malignant obstruction. It is associated with a lower incidence of intensive care unit admission, shorter hospital stay, lower stoma rate, and earlier chemotherapy administration. Laparoscopic or robotic surgery can then be performed in an elective setting on a prepared bowel. Therefore the patient benefits from advantages of the combination of 2 minimally invasive procedures in a nonemergent situation. Further large-scale prospective studies are necessary.

Ten-year retrospective study of treatment of malignant colonic obstructions with self-expandable stents

PURPOSE

To describe the use of self-expandable metallic stents to manage malignant colorectal obstructions and to compare the radiation dose between fluoroscopic guidance of stent placement and combined endoscopic and fluoroscopic guidance.

MATERIALS AND METHODS

From January 1998 to December 2007, 467 oncology patients undergoing colorectal stent placement in a single center were included in the study. Informed consent was obtained in all cases. All procedures were performed with fluoroscopic or combined fluoroscopic and endoscopic guidance. Inclusion criteria were total or partial colorectal obstruction of neoplastic origin. Exclusion criteria were life expectancy shorter than 1 month, suspicion of perforation, and/or severe colonic neoplastic bleeding. Procedure time and radiation dose were recorded, and technical and clinical success were evaluated. Follow-up was performed by clinical examination and simple abdominal radiographs at 1 day and at 1, 3, 6, and 12 months.

RESULTS

Of 467 procedures, technical success was achieved in 432 (92.5%). Thirty-five treatments (7.5%) were technical failures, and the patients were advised to undergo surgery. Significant differences in radiation dose and clinical success were found between the fluoroscopy and combined-technique groups (P < .001). Total decompression was achieved in 372 cases, 29 patients showed remarkable improvement, 11 showed slight improvement, and 20 showed clinical failure. Complications were recorded in 89 patients (19%); the most significant were perforation (2.3%) and stent migration (6.9%). Mean interventional time and radiation dose were 67 minutes and 3,378 dGy·cm(2), respectively.

CONCLUSIONS

Treatment of colonic obstruction with stents requires a long time in the interventional room and considerable radiation dose. Nevertheless, the clinical benefits and improvement in quality of life justify the radiation risk.

Complications of colonic stenting: a pictorial review

Surgical resection of colorectal carcinoma is the only curative treatment currently available. In the elective setting peri-operative mortality is low and refinements in surgical technique and peri-operative care have resulted in high primary anastamosis rates and progressively reduced postoperative morbidity. In those presenting with large bowel obstruction the mortality and morbidity remains high. Many of those undergoing surgery will have incurable disease and a short life expectancy. Increasingly self-expanding metal stents are being deployed as either a 'bridge to surgery' or for palliation. This review covers the imaging appearances, detection and management of complications of colonic stenting.