Single Balloon Enteroscopy: Detailed Procedural Guide
Single balloon enteroscopy (SBE) is a safe and effective device-assisted enteroscopy technique that allows deep small bowel examination with comparable performance to double-balloon enteroscopy, achieving mean insertion depths of 132 cm beyond the ligament of Treitz via the antegrade approach and 73-118 cm above the ileocecal valve via the retrograde approach. 1, 2, 3
Pre-Procedure Preparation
Patient Preparation Requirements
Fasting for at least 12 hours is required for oral (antegrade) approach, with avoidance of liquid consumption for 4 hours prior to the procedure 1
Standard colonoscopy bowel preparation is mandatory for retrograde (anal) examination, similar to conventional colonoscopy preparation 1
Deep sedation or general anesthesia is required due to the clinically challenging nature of device-assisted enteroscopy 1
The procedure can be performed with gastroenterology-administered sedation using midazolam, pethidine, and propofol without significant respiratory or hemodynamic complications in 87.5% of cases 4
Equipment Setup
Single-balloon enteroscopy system consists of an enteroscope with an overtube equipped with a single inflatable balloon 1, 5
CO2 insufflation instead of room air is highly recommended, as it improves intubation depth and reduces post-procedural discomfort, particularly preventing paralytic ileus 1, 4
Fluoroscopy may be used selectively (approximately 12% of cases) to assist with advancement and confirm depth of insertion 2
Procedural Technique
Approach Selection
Antegrade (oral) approach is used in approximately 83% of cases and is the primary route for proximal and mid-small bowel examination 2
Retrograde (anal) approach is used in approximately 17% of cases for distal small bowel and terminal ileum evaluation 2
The approach should be selected based on the suspected location of pathology identified on prior imaging or capsule endoscopy 6, 5
Antegrade (Oral) Technique
Mean procedure time is 38-49 minutes for the antegrade approach 5, 2
The enteroscope is advanced through the esophagus, stomach, and duodenum to reach the ligament of Treitz 2
The balloon on the overtube is inflated to anchor the system, allowing push-and-pull maneuvers to pleat the small bowel over the enteroscope 1
Typical insertion depths achieved:
- Proximal jejunum: 34% of cases
- Mid-jejunum: 45% of cases
- Distal jejunum: 21% of cases 5
Average maximum insertion depth is 132 cm beyond the ligament of Treitz (range 20-400 cm), with some studies reporting mean depths of 253-258 cm from the incisors 2, 3
The push-pull technique involves inflating the balloon to grip the bowel wall, advancing the enteroscope, deflating the balloon, and repeating the cycle to progressively telescope the small bowel 1
Retrograde (Anal) Technique
Mean procedure time is 48-110 minutes for the retrograde approach, which is longer than the antegrade route 5, 4
The enteroscope is advanced through the colon to the ileocecal valve and into the terminal ileum 2
Average insertion depth is 73-118 cm above the ileocecal valve (range 10-160 cm) 2, 3
The same balloon-assisted push-pull technique is employed to advance through the ileum 1
Special Considerations for Altered Anatomy
SBE can be successfully performed in patients with surgically altered anatomy (7.5% of cases), including those with Roux-en-Y anatomy 4
Newer short-type single balloon enteroscopes have success rates of 92.6-97% in reaching the blind end of the duodenum in patients with altered anatomy, with treatment success of 81.8-100% 1
Diagnostic and Therapeutic Capabilities
Diagnostic Yield
Overall diagnostic yield ranges from 47-58% across multiple studies 5, 2
Most common findings include:
Therapeutic Interventions
Therapeutic yield is 39-42%, demonstrating significant clinical utility beyond diagnosis 6, 2
Therapeutic procedures include:
Primary Indications
Obscure gastrointestinal bleeding is the most common indication (72-97% of cases) 6, 5, 4
Other indications include:
Safety Profile and Complications
Complication Rates
The risk of hemorrhage from diagnostic enteroscopy is 0.2-0.3%, which is very low 1
Perforation rate is 0.1-0.4% for diagnostic procedures, rising to 1.5% when polypectomy is performed 1
Overall major complication rate is estimated at 0.7% in IBD patients, comparable to other populations 1
Multiple large studies report no significant complications in their case series 5, 2
Specific Complications to Monitor
Paralytic ileus is the most common complication, occurring in approximately 2.5% of cases 4
Both reported cases of paralytic ileus were associated with NOT using CO2 insufflation, emphasizing the critical importance of CO2 use 4
Post-procedural discomfort can occur but is significantly reduced with CO2 insufflation 1
Common Pitfalls and How to Avoid Them
Failure to use CO2 insufflation - This is the single most important modifiable risk factor for complications, particularly paralytic ileus; always use CO2 instead of room air 1, 4
Inadequate bowel preparation for retrograde approach - Ensure full colonoscopy-level preparation to optimize visualization and prevent premature termination 1
Excessive pressure on fresh staple lines - In post-bariatric surgery patients, minimize pressure along staple lines when advancing the enteroscope 1
Performing therapeutic interventions on anticoagulation - While diagnostic SBE is low risk (0.2-0.3% bleeding), therapeutic procedures such as polypectomy confer high hemorrhage risk on antithrombotics and require appropriate management 1
Inadequate sedation - Deep sedation or general anesthesia is necessary; inadequate sedation leads to patient discomfort and procedural failure 1
Performance Comparison
SBE demonstrates non-inferiority to double-balloon enteroscopy (DBE) with comparable oral insertion depths (258 cm vs 253 cm), diagnostic yield, and patient discomfort scores 3
Complete small bowel visualization is achieved in 11-18% of procedures with either technique 3
SBE offers simplified preparation and handling compared to DBE while maintaining equivalent clinical performance 3