Endoscopic Placement of Colonic Self-Expanding Metal Stent for Malignant Obstruction

CASE REPORT

Klaus Mönkemüller, MD, PhD, FASGE, FESGE, FJGES, Professor of Medicine, Department of Gastroenterology, Virginia Tech Carilion School of Medicine

Final Diagnosis

Malignant colonic obstruction due to metastatic colon cancer, treated with endoscopic placement of a self-expanding metal stent.

Patient Demographics

A 70-year-old female.

Clinical History

The patient presented with acute colonic obstruction in the setting of metastatic colon cancer. The indication for endoscopy was to place a decompressing self-expanding metal stent.

Endoscopic Findings

Endoscopy revealed a tight stenosis in the distal sigmoid colon. Imaging studies, including computed tomography, confirmed the presence of a large metastasis and colonic obstruction with distended large and small bowel loops (A, B, C, yellow arrow).

Endoscopic Technique

1. A therapeutic gastroscope with a 3.7 mm working channel was utilized for the procedure.
2. The stenosis was visualized endoscopically (D).
3. Using a biliary balloon catheter a J-0,035 inch biliary guidewire was carefully advanced through the stenosis under combined endoscopic and fluoroscopic guidance (E).
4. Contrast was administered through the catheter to confirm its position within the dilated colon (E, F, yellow oval).
5. The guidewire was deeply advanced into the colon, ensuring sufficient length distal to the endoscope for safe stent delivery (F).
6. To estimate the length of the stricture, the biliary balloon was inflated and gently pulled back until resistance was met (F).
7. The self-expanding metal stent was advanced into the colon over the guidewire.
8. Under endoscopic visualization, the proximal part of the stent was released and allowed to expand proximally (G). It is always essential to gently pull back the endoscope, as well as the delivery catheter as the distally expanding metal stent can „shoot up“ proximally during deployment. Therefore, this „scope and catheter pull-back“ repositioning maneuver is an essential part of colon stent deployment.
9. The stent delivery catheter was continuously monitored endoscopically, using a yellow marking to ensure proper proximal positioning of the stent (see endoscopy photo insert in panel G).
10. The stent fully expanded immediately after deployment, as confirmed by endoscopic and fluoroscopic views, effectively decompressing the obstruction (H).

Discussion

Malignant colonic obstruction is a common complication of advanced colorectal cancer, frequently requiring urgent decompression. Initial management strategies often involve surgical intervention, but in cases of advanced disease or high surgical risk, endoscopic placement of self-expanding metal stents (SEMS) offers a less invasive alternative for palliation and bridge to surgery. The choice of endoscope with an adequate working channel is critical for successful stent delivery. Small working channels (e.g., in pediatric colonoscopes or scopes less than 3.2 mm) are often insufficient for accommodating the stent delivery system. Fluoroscopic guidance is indispensable for accurate wire placement, real-time monitoring of stent deployment, and confirmation of position. Precise length estimation of the stricture, as demonstrated by contrast injection and the balloon pullback technique, aids in selecting an appropriately sized stent and minimizing the risk of migration or inadequate coverage. Post-deployment, SEMS may take several hours to days to fully expand and might not necessitate immediate balloon dilation, though this can be considered in cases of persistent luminal narrowing. The described technique highlights key maneuvers to optimize stent placement and ensure adequate decompression in patients with malignant colonic obstruction.

Key Learning Points

1. Utilize an endoscope with a sufficiently large working channel (e.g., therapeutic gastroscope) for self-expanding metal stent delivery in colonic obstruction.
2. Employ combined endoscopic and fluoroscopic guidance for accurate guidewire placement and stent deployment.
3. A balloon-tipped catheter can aid in confirming guidewire position and estimating stricture length.
4. Ensure deep guidewire advancement and maintain endoscopic visualization of the stent delivery catheter for optimal stent positioning.
5. Stents typically expand over several hours to days, and immediate balloon dilation is often not required.

References

1. Small AJ, Coelho-Prabhu N, Lieberman DA, et al. American Society for Gastrointestinal Endoscopy guideline on the role of endoscopy in the management of colorectal cancer. Gastrointest Endosc. 2017;85(4):689-701.
2. Van Hooft JE, van Halsema EE, Vanbiervliet G, et al. Self-expandable metal stents for the palliation of malignant colonic obstruction: updated recommendations from the European Society of Gastrointestinal Endoscopy. Endoscopy. 2014;46(12):1070-1081.
3. Spinelli A, Galasso E, Contino G, et al. Endoscopic stenting for malignant colorectal obstruction: A systematic review and meta-analysis of outcomes in 2200 patients. Dig Liver Dis. 2018;50(1):11-18.