Enteral Stents Flashcards
before putting a stent , should do ?
- A thorough physical examination and radiographic imaging should be performed to exclude a surgical abdomen and luminal perforation.
Benign Vs malignant etiology
- Inflammatory, ischemic, or anastomotic colon strictures can often be managed with endoscopic balloon dilation.
- Malignant colonic strictures will not respond to endoscopic balloon dilation, which also carries a non-trivial risk of perforation
Malignant colonic obstruction (MCO) is primarily caused by
left-sided colorectal cancer
What about Rt Side ?
- presents less frequently with colonic obstruction and is often managed with one-stage surgery without the need for bowel preparation or permanent stoma formation.
Do you put Stent on Rt Side?
The outcomes of SEMS deployment in this group are conflicting, and prospective trials are warranted.
three main indications for SEMS placement in patients with MCO:
(1) bridging to elective surgery
(2) palliation in nonoperative candidates
(3) overcoming extrinsic compression from extracolonic tumors.
International guidelines ?
- lack of high-quality evidence to define the best management strategy in terms of morbidity, mortality, and long-term oncologic outcomes.
- Clinical practice guidelines are more consistent in the setting of disease palliation.
Benefit of Bridge to Elective Surgery
- Restoration of bowel function with a one-stage operation and avoiding the need for an ostomy, thus also improving quality of life (QoL)
- Conversion of an emergency surgery to an elective surgery
- Nutritional optimization
- Improvement of surgical outcomes > complication rates, shortening hospital stays, and increasing rates of primary anastomosis
- optimization of underlying comorbid medical illnesses
- Reduction of morbidity and mortality associated with surgery
- Increasing time for optimal staging workup and administration of neoadjuvant therapy
What was the Conflict regarding Stent ?
Conflicting results in terms of adverse events and oncologic safety.
> SEMS may cause microperforations that result in peritoneal seeding and increase the risk of metastatic spread.
Recent guidelines have again begun advocating stenting as a BTS including the updated 2020 ESGE guidelines
- Recommend colonic stenting as a BTS to be discussed, within a shared decision-making process, as a treatment option in patients with potentially curable left-sided obstructing colon cancer as an alternative to emergency resection.
(EAST) conditionally recommends
SEMS in comparison with open surgery, when available, as it has shown to decrease mortality and decrease emergency procedures.
what is the goal of stent in palliative cases and what does the guideline say
- The goal
> prolong survival and improve QoL - The surgical and gastroenterology guidelines are more consistent, recommending stenting as the preferred alternative to decompressive surgery.
SEMS Vs Surgery for palliative Cases
- SEMS resulted in a shorter hospital stay and lower rates of permanent colostomy
How to select patients for Stent in palliative Care ?
- Patient selection should be dictated by a multidisciplinary consultation or tumor board meeting.
any role of Prophylactic Stenting ?
- prophylactic colonic stent placement is not recommended in patients who are not yet symptomatic.
Extracolonic malignancy resulting in extrinsic compression of the lumen is rare, what are the causes
- The most common causes include
gynecologic (ovarian and uterine) malignancies
bladder cancer
advanced gastric cancer
metastatic lesions to the pelvis.
Stent for Extracolonic causes is a Challenge why ?
(1) Tumors are multifocal, compressing a long segment of large bowel, and often associated with peritoneal carcinomatosis
(2) most patients have an extensive surgical history with dense pelvic adhesions or have had prior exposure to radiotherapy.
The technical and clinical successes of stenting are lower when compared with primary colorectal tumors.
- Need Proper patient and family counseling
- setting a realistic expectation
- preparing the patient for potential surgical intervention in case of technical failure or long-term failure.
Benign Strictures, Causes
- Diverticulitis
- inflammatory bowel disease
- ischemia
- radiation
- postoperative anastomotic strictures
- Complex colorectal fistulas including colovesical and colovaginal fistulas.
- Anastomotic strictures are known to be the most common complication following colonic surgery
- The bulk of scientific literature on the management of benign colonic strictures stems from Crohn’s disease
Morphology of benign Vs Malignant Stricture
- benign strictures > increased fibrosis and scarring; thus, therapy is more challenging.
Endoscopic therapies for Benign Strictures
- balloon dilation (EBD)
- intralesional steroid injections
- SEMS placement
- endoscopic incisional therapies
- lumen-apposing metal stent (LAMS).
Initial Endoscopic Tx
- Graded EBD is the recommended initial treatment for benign strictures
- high clinical success exceeding 88%
- high recurrence rate of 30% to 88%, often requiring redilations.
Who will have less favorable outcome
- Patients with complex anastomoses or multiple strictures are less likely to have favorable treatment outcomes
compared with those with a short (< 4 cm) focal stricture in a straight colonic segment.
When to Avoid dilatation in Crohns
- active inflammation
- presence of large ulcers within a stricture
- or smoking.
Any adjunct with dilatation ?
- Intralesional steroid injection
enhance the effectiveness of balloon dilation, reducing the time to redilation, and should be considered, especially in cases of acute inflammatory strictures.
SEMS should not be used as first-line therapy for benign strictures
> not removable and may predispose patients to long-term complications.
fully covered self-expandable metal stents (FCSEMS) in benign colonic strictures
- not FDA approved
- off-label use of FCSEMS considered in refractory or recurrent benign colonic strictures.
- their drawbacks include
patient intolerance, iatrogenic stricture formation, and a high rate of early stent migration of up to 40%
covered esophageal stents ?
- off-label manner to treat benign colonic strictures.
- most covered esophageal stents come on a stiff introducer and within short catheters and must be passed over a guidewire thus limiting their use to left-sided colonic strictures.
Endoscopic incisional therapies
- Using a sphincterotome or a needle-knife to perform strictureplasty allows for controlled radial mucosal incisions along the circumference of the stricture.
LAMS
- an alternative to other traditional endoscopic therapies.
- The unique design > facilitate stent retention, which improves patient tolerance and makes them less prone to migration
- Their safety and long-term efficacy data are lacking
Summary of management of colonic obstruction/ stricture.
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Absolute Contraindications to SEMS Placement
Colonic perforation or severe colonic ischemia with impending necrosis
Relative Contraindications to SEMS Placement
- Distal rectal lesions with 5 cm from the dentate line (stents crossing the anal verge can induce severe pain, tenesmus, bleeding, and risk of migration)
- Presence of diffuse peritoneal carcinomatosis (higher failure rate)
- Persistent severe coagulopathy (risk of bleeding)
- Patients on chemotherapy with antiangiogenic drugs (such as bevacizumab)
- Tumors close to the anal verge (< 5 cm)
Special considerations
- Lesions in tortuous or angulated portions of the colon, such as the splenic flexure (technically challenging and may have a higher failure rate)
- The use of prophylactic stents in patients with metastatic disease to prevent potential obstruction is not recommended
- Right-sided or proximal colonic lesions are better managed with surgical resection with primary anastomosis or stoma creation.
Do you use Covered or Uncoveres SEMS ?
Uncovered
high rate of migration associated with covered SEMS.
Stent Dimensions and material
5.7 and 12 cm in length
mid-body diameters of 20 to 30 mm
within a 10Fr catheter
-stainless steel
-Nitinol (comprising nickel and titanium)
-Elgiloy (comprising cobalt, chromium, and nickel).
Nitinol is the most widely used metal alloy
> malleability at low temperatures and strong radial forces at body temperature without losing its flexibility
Stainless steel > stiff and affect quality of imaging (MRI)
Elgiloy are thinner, more elastic, and more flexible, and they are MRI-compatible
Covered Vs Uncovered
Covered stents > fully and partially covered
> reduce the risk of tumor ingrowth
> used to seal fistulas
fully covered stents have less anchoring power
> increased risk of migration compared with uncovered stents.
Partially covered stents with flared uncovered segments at both ends were developed to overcome migration risk.
Covered Vs un Covered
uncovered :
lower risk of complications
tumor overgrowth
stent migration
longer duration of patency
lower need for stent reinsertion
higher risk of tumor ingrowth
Prerequisites for Stent Placement
- history and physical examination; rule out perforation
- Assess location and morphology of stricture with Retrograde barium/ Gastrografin enema or CT with contrast
- Avoid oral mechanical bowel prep; consider enemas
- Diagnostic colonoscopy (some cases)
Prophylactic Abx?
Only in patients with complete obstruction and dilated colon proximally, prophylactic intravenous antibiotic therapy is recommended
> during insufflation > may cause microperforations resulting in bacterial translocation.
Intraprocedural
- Endoscopy suite or operating room
- General anesthesia preferred
- Left lateral position
- Therapeutic gastroscope or colonoscope (depending on location)
- CO2 insufflation > Rapid absorption , reduce risk of perforation
Stent Deployment
- Combined endoscopy and fluoroscopy technique
- TTS stent deployment with guidewire
In Case of Difficulties > simultaneous side-by-side endoscopy with a small-caliber endoscope is recommended
( rectal or sigmoid strictures, acute angulations, or other conditions with poor endoscopic visualization )
Coverage Overlap
SEMS should be of suitable length to bridge the stricture and extend at least 2 cm on each side of the obstruction once the stent is deployed.
If stent coverage is inadequate, an additional stent can be deployed overlapping the existing stent.
In patients who present with complete colonic obstruction
- leaving the guidewire in place after stent deployment to pass a colonic decompression tube through the stent and into the proximal bowel if immediate passage of stool does not occur after stent placement.
For right-sided colonic obstruction
typically require a TTS SEMS placed via an adult colonoscope.
Follow up after Stent Placement
- large bowel decompression, confirmed on endoscopy
- nasogastric tube often removed the following day.
- abdominal radiograph or CT is obtained immediately after stent placement to confirm position and exclude free air
- x-ray is repeated within 24 to 48 hours when full expansion of the stent is expected
- A liquid diet can typically be initiated within 24 to 48 hours
- Several days are needed for complete decompression to a normal-sized colon.
what factor known to increase the rate of perforation
- Angiogenesis inhibitors (e.g., bevacizumab) are independent risk factors of perforation
Stent migration or failure
raise suspicion for stent malposition (inadequate stricture coverage), incomplete expansion, or undetected synchronous tumors.
Short stents, smaller-diameter stents (< 25 mm), and covered stents have higher rates of migration.
managed endoscopically by removing the migrated stent with the goal of either placing a larger stent or a different type of stent
how to manage Tumor ingrowth and fecal impaction
endoscopically by placing another stent through the occluded stent.
Abdominal/ rectal pain and incontinence may occur if stents are placed within
5 cm of the anal verge.
