Important Tips of Enteric Stent Successful Placement for Malignant Stenosis

In recent year, the mortality rate of the enteric tumor continuously decreases due to advanced skills of diagnosis and treatment. For the unresectable colon and rectal tumors, enterostomy was once been the main choice. While presently stent implantation is a good and effective choice as well. 

The rate ofsuccessful operation for enteric stent implantation could be higher than 90%. With stent implantation, it could solve the acute obstruction and promise the patency of the cavity within short term in order to prepare for further operation.

With 20 years’ clinical practice, the palliative effect of rectal stent got confirmation of worldwide researchers. It is the rapid and effective minimal invasive treatment for enteric obstruction.

Here we wish to give you some suggestions which are from UEG education and stent manufacturers. We believe they are useful and could facilitate stent release procedures and reduce pain for the patients.

1.    Proper preparation

High-quality interventions begin with proper preparation. For stent placement, the most recent radiological images must be examined before surgery. In particular, factors such as the area in which the stent is to be released, its position and length, and its relationship to surrounding structures, are important. This information is used to ensure that the endoscopic physicians select the best stent for a particular patient (for example, length, diameter, radial force, and cover situation).

2.    The importance of pathological examination

In most cases, a pathological determination of malignancy is required before stent placement. Most benign lesions in the colon are caused by diverticulosis, which sometimes looks similar to colon cancer. Since diverticulosis is a contraindication to colon stent placement which shall increases the risk of perforation, pathological evidence of malignancy is preferred. In patients with acute intestinal obstruction with stent for decompression, intra operative biopsy should be performed. If pathological obstruction results from benign disease, surgical resection and stent placement should be performed as soon as possible.

3.    Gastric decompression before placing the stent

Failure to perform gastric decompression before stenting in intestinal or gastric outlet obstruction increases the risk of aspiration. Simply requiring patients to fast 6 hours before surgery is not appropriate. It is important to change the patient to liquid diet 24 hours before operation. Nasal gastric suction tube should be placed 2-6 hours before operation. In case of long time obstruction, dilatation of the stomach and gastric weakness are common situations. At this time, the stability of endoscopic and stent-pushing system through the great gastric curvature will be affected, which may increase the difficulty of surgery.

4. Fluoroscopy and endoscopy should be used both

Colon stents are usually placed using the TTS stent system. The European society for digestive endoscopy's guidelines recommend a combination of endoscopic monitoring and fluoroscopy to guide the placement of colon stents, as several studies have shown that this combined approach contributes to a higher success rate. Therefore, the best way to place the colon stent is under the endoscopic field of vision, and under the real-time guidance of fluoroscopy, through the early contrast agent injection, in order to confirm that the guide wire is in the correct position before stent release.

In the case of duodenal stent placement, the rates of X-ray fluoroscopy alone and endoscopic field guidance combined with X-ray fluoroscopy are reported to be similar. However, we recommend that the placement of the duodenal stent should also be done with combined monitoring, because combined endoscopic field monitoring helps obtain biopsy samples under the endoscope.

5.    Guide wire choosing

The advantage of soft guide wire is that it is easier to pass through twisted and narrow paths, but it is not stiff enough to support the stent pusher to reach the target position, especially if some colon is twisted or in the enlarged stomach cavity. Therefore, a longer and harder guide wire should be considered first to provide better support. It should also be noted that even a 5-meter guide wire used in a relatively long colonoscopy is not ideal for handling a guide wire. Therefore, when placing a colon stent, it is better to use a long (> 4 m) guide wire and a therapeutic gastroscope or sigmoidoscopy for optimal guidance.

6. Know the stent performance after implantation

A. Stent choice

Stents from different manufacturers differ in the length, diameter, and cover. In addition, the pusher devices are various as well. Some stents are released by a     “back pull "system, while others are released by a proximal release mechanism through a “forward push" system. In addition, the X-ray markings vary as well.

Therefore, these details need to be confirmed before surgery. Some stents may be shortened by more than 30 percent of their length after full release, while others do not.

Therefore, to ensure proper stent release, the surgical team must be familiar with the characteristics of the stent and the pusher prior to surgery.

B. Stent release

During the release of the stent, the stent will gradually move away from the center of the stenosis, especially in the severe narrow position. This shift occurs because the stent has a tendency of radial spreading tension after the stent is deployed towards the distal end. If this is not noted, a severe narrowing of the squeeze combined with a strong expansion of the stent can result in an inaccurate placement of the stent. Therefore, endoscopes must pay attention to this phenomenon and apply corresponding reaction force so as to make the positioning of stent accurate.

Remember to leave the guide wire in place until the stent is released to ensure that the stent is positioned correctly. In case the stent migrates, the remaining guide wire could facilitate the introduction and release of another stent.

C. Stent fully expanding time

Full stent expansion usually takes 48 hours! Patients should therefore be clearly advised to maintain a liquid or soft diet for 2-3 days after surgery. Also the patient understand that stents cannot always achieve 100% complete expansion.

For example, when the tumor is very large or narrowness is severe. In particularly severe strictures, the extent of stent expansion is limited within a few minutes after the stent placement, and it may not be possible to remove the pusher. Forced removal of the stent pusher at this time may result in dislocation of the stent. However, the narrow stricture where the stent is placed cannot be dilated because such an operation is known to be at risk of perforation.

7. Patients need to know more

 Too little information was provided to patients about surgery and complications. Potential complications are usually stated in the patient's informed consent, including perforation, bleeding, stent displacement, re-obstruction, and so on. Patients also need to be informed about sedation-related complications, such as the risk of aspiration.

Severe postoperative pain is an important complication. It may occur after stent implantation, especially after esophageal stent implantation. Physicians should inform patients of this complication and that the postoperative pain is usually self-limiting. It is also important to make it clear to patients that esophageal stent placement does not always resolve dysphagia. It is necessary to adjust the diet. At the beginning, only liquid food can be taken, and then gradually transition to soft food, and finally return to normal eating according to the individual situation of patients. 

In addition, patients should be instructed to drink adequate amount of water before and after each meal to reduce the risk of food impaction. Similarly, patients must adjust their dietary habits after placing a duodenal stent. Patients with stents in the upper gastrointestinal tract should also be careful to sit up straight for at least 30 minutes after each meal. Finally, patients should be informed that after placing a colon stent, a high-fiber diet or a high-fiber diet combined with laxatives/laxatives can help prevent fecal impaction.

In conclusion, patients should be informed of potential discomforts and have the opportunity to contact the attending physician and, if necessary, stent should be repositioned.

8. How to implant enteric stents:

Stent implantation is associated with endoscope and X -ray. Firstly observe the  location of the stricture from endoscope.  Then insert guide wire and make sure it passes the stricture under X ray. Inject contrast agent. Check carefully the stricture length and diameter, choose proper specification of the stent. Tip: Stent should cover the whole length of the stricture and exceed each end by 2 CM.

9. Other tips for successful stent implantation

.Distal release first is easier to make positioning. Adjust the stent position when the stent is partly release.

.Careful mental nursing before operation is critical. The patients with calm mood and well noted about how to cooperate with the physician are proved to have greater successful rate and satisfaction. After the operation, watch carefully if the patients have intensive abdominal ache or swelling pain. Make X ray inspection in time to prevent perforation.

Ref articles: UEG education, EndoNews, Gastrointestinal Stents（Editor: Fan Zhining）