Overview
Definition:
Colonic stent placement is an endoscopic or radiologic procedure involving the insertion of a self-expanding metallic stent into a narrowed segment of the colon, typically caused by malignant strictures, to re-establish luminal patency
This palliation aims to relieve symptoms of bowel obstruction and improve quality of life.
Epidemiology:
Malignant colonic obstruction occurs in approximately 15-30% of patients with colorectal cancer, with a higher incidence in elderly patients or those with unresectable disease
Colorectal cancer is the third most common cancer globally, contributing significantly to obstruction rates.
Clinical Significance:
Colonic stenting offers a less invasive alternative to emergency surgery for malignant colonic obstruction, reducing morbidity and mortality associated with emergency laparotomy and ostomy creation
It provides rapid symptom relief and allows for elective definitive treatment
This procedure is crucial for surgical residents to understand in managing a common and complex oncological emergency.
Indications
Absolute Indications:
Malignant colonic obstruction causing significant symptoms (pain, vomiting, distension) in patients unfit for immediate surgery
Palliation of symptoms in unresectable or metastatic colorectal cancer
Bridge to elective surgery in select patients.
Relative Indications:
Benign strictures causing obstruction (e.g., post-radiation, inflammatory bowel disease) where surgery is high-risk
Diversionary stoma reversal facilitation
Intestinal decompression pre-operatively in high-risk patients.
Contraindications:
Perforation
Complete bowel obstruction with extensive necrosis
Active peritonitis
Uncontrollable coagulopathy
Patients with very short life expectancy where the risks outweigh benefits.
Preoperative Preparation
Patient Assessment:
Thorough history and physical examination focusing on symptoms of obstruction, comorbidities, performance status (ECOG/Karnofsky), and fluid/electrolyte balance
Review of prior imaging and investigations.
Imaging:
CT scan of the abdomen and pelvis with oral and IV contrast is essential to confirm the diagnosis, assess the level and extent of obstruction, identify the primary malignancy, and detect complications like perforation or distant metastases
Colonoscopy may be performed to visualize the lesion and obtain biopsies.
Laboratory Tests:
Complete blood count (CBC) for anemia and infection markers
Liver function tests (LFTs) and renal function tests (RFTs) to assess organ function
Coagulation profile to assess bleeding risk
Electrolytes and serum albumin for nutritional status and fluid balance.
Bowel Preparation:
Clear liquid diet for 24-48 hours pre-procedure
In some cases, oral laxatives or polyethylene glycol solutions may be administered under medical supervision, though aggressive bowel preparation is often avoided in acute obstruction to prevent exacerbation of symptoms or perforation.
Procedure Steps
Endoscopic Approach:
Under sedation or general anesthesia, a colonoscope is advanced to the stricture
Guidewire insertion across the narrowed segment is crucial
Balloon dilation may be performed prior to stent deployment
The stent is then deployed under direct endoscopic visualization and fluoroscopic guidance
Post-deployment imaging confirms stent position.
Radiologic Approach:
Under local anesthesia and fluoroscopic guidance, a percutaneous tract is established across the stricture
A guidewire is advanced through the obstruction
Balloon angioplasty may be performed
The stent is then deployed over the guidewire
Access is typically obtained via a transperitoneal or transcolonic route.
Stent Types:
Self-expanding metallic stents (SEMS) are commonly used
Options include uncovered, partially covered, and fully covered stents
Choice depends on the tumor location, risk of migration, and need for future resection.
Postoperative Care
Immediate Monitoring:
Close monitoring for signs of bleeding, perforation, or stent migration
Vital signs, abdominal examination, and pain assessment are critical
Adequate intravenous fluid resuscitation and pain management are provided.
Pain Management:
Opioid analgesics are typically required for immediate post-procedure pain
Transition to oral analgesics as tolerated
Patient-controlled analgesia (PCA) may be used.
Nutritional Support:
Initiation of clear liquids followed by a low-residue diet as tolerated
Parenteral or enteral nutrition may be required in cases of persistent ileus or significant malabsorption
Education on dietary modifications to prevent further obstruction.
Ambulation And Discharge:
Early ambulation is encouraged
Discharge typically occurs within 24-72 hours if no complications arise
Follow-up colonoscopy or imaging is scheduled as per institutional protocol, usually within 4-6 weeks, to assess stent patency and evaluate the tumor.
Complications
Early Complications:
Perforation (0.5-5%)
Bleeding (1-3%)
Stent migration or displacement (2-7%)
Abdominal pain
Nausea and vomiting
Peritonitis
Sepsis.
Late Complications:
Stent restenosis due to tumor ingrowth or overgrowth (5-15%)
Stent fracture
Impaction of stool
Fistula formation
Malignant recurrence.
Prevention Strategies:
Meticulous technique during stent deployment
Use of appropriate stent length and diameter
Careful patient selection
Aggressive pain and nausea management
Post-procedure surveillance to detect early signs of complications
Consideration of covered stents for specific indications.
Prognosis
Factors Affecting Prognosis:
Stage of the underlying malignancy
Patient's performance status and comorbidities
Presence of distant metastases
Success of stent placement in relieving obstruction
Occurrence of complications.
Outcomes:
Successful stent placement offers good palliation for symptoms of obstruction in up to 80-90% of patients, improving quality of life and enabling elective surgery in suitable candidates
Median survival varies widely based on cancer stage and treatment, typically ranging from months to over a year.
Follow Up:
Regular follow-up is essential, including clinical assessment, tumor marker monitoring (CEA), and imaging
For palliation, follow-up focuses on symptom control and quality of life
For patients undergoing bridge-to-surgery, follow-up is directed towards definitive cancer treatment and long-term oncological surveillance.
Key Points
Exam Focus:
Indications for palliative stenting in malignant colonic obstruction
Contraindications to stenting
Complications of colonic stent placement
Role of SEMS in managing acute colonic obstruction
Differentiating SEMS from surgical options.
Clinical Pearls:
Always ensure adequate guidewire passage across the stricture before stent deployment
Fluoroscopy is vital for accurate stent positioning
Close post-procedure monitoring for early detection of perforation is paramount
Consider stent type based on tumor characteristics and risk of migration.
Common Mistakes:
Inadequate pre-procedure assessment leading to inappropriate patient selection
Failure to ensure adequate guidewire passage
Misjudging the length of the stricture for stent selection
Delaying management of complications
Over-reliance on stenting in patients with very short life expectancy or active peritonitis.