Background

Submucosal tunneling endoscopic resection (STER) is an advanced technique for removing subepithelial tumors in the gastrointestinal tract.

Endoscopic submucosal dissection effectively treats superficial lesions but poses higher perforation risks with muscularis propria tumors.

STER inspired by peroral endoscopic myotomy (POEM) is a minimally invasive method for SET removal to preserve mucosal integrity through submucosal tunnel creation.

Effectiveness and safety of STER should be evaluated for esophageal and cardial tumors.

Accurate subtype diagnosis of SMTs remains challenging without resection, despite endoscopic ultrasound-guided fine needle aspiration and biopsy being reliable histological methods.

A tunnel is created between the mucosa and MP layer for tumor resection. Endoscopic techniques are deemed effective and safe for MP SMT resection.

This retrospective study assessed the effectiveness and safety of STER for gastrointestinal SMTs from the MP layer.

Indications

Gastrointestinal stromal tumors

Leiomyomas

Schwannomas

Esophageal and Gastric Leiomyomas

Neuroendocrine Tumors

Heterotopic Pancreas

Contraindications

Malignant or High-Risk Tumors

Tumors with Deep Extraluminal Extension

Extensive Tumor Infiltration

Severe Coagulopathy or Bleeding Disorders

Severe Cardiorespiratory Conditions

Large Tumors

Tumors in Difficult Locations

Severe Fibrosis or Previous Interventions

Outcomes

Imaging advancements have increased SMT detection rates, with an incidence reported at 3%.

Intact mucosa makes EUS-FNA and biopsy more challenging for SMTs originating in the MP layer.

STER is the preferred technique for resecting SMTs from the MP layer due to its high en bloc resection rate and mucosal preservation.

Large size, deep invasion, and proximity to the aortic arch increase residual tumor risk.

No significant differences found in resection or complication rates.

Esophageal complications mainly included gas-related issues and fever while cardia had mucosal injuries most frequently.

Equipment required

High-Definition Endoscope

Carbon Dioxide Insufflator

Injection & Submucosal Lifting

Endoscopic Dissection Tools

Tumor Retrieval Tools

Mucosal Closure Devices

Patient Preparation:

Patient selection and evaluation includes imaging studies, risk assessment, and bowel preparation.

General anesthesia is preferred for airway protection in tumors.

Informed Consent:

Explain the procedure’s risks and potential complications clearly to the patient.

Patient Positioning:

Patients should be positioned in supine position for gastric lesions.

Figure. Submucosal tunneling endoscopic resection of GI tract

Technique

Step 1: Mucosal Entry Creation

A solution is injected to lift the mucosa to create a working space.

Then a small longitudinal incision is done in the esophageal or gastric mucosa using an endoscopic knife. Entry site facilitates access for submucosal tunneling.

Step 2: Submucosal Tunnel Creation

The endoscope is inserted into the mucosal entry, and a tunnel is extended toward the tumor.

The submucosal fibers are carefully dissected using endoscopic knives.

The tunnel is expanded to fully expose the tumor that avoids muscularis propria injury.

Step 3: Tumor Dissection and En Bloc Resection

The tumor is isolated from the surrounding muscularis propria. Perform En bloc removal to ensure complete excision.

Small bleeding vessels are coagulated using hemostatic forceps or spray coagulation.

Endoscopic clips may be used for larger vessels. Tumor removed through mucosal entry using snare or retrieval device.

Step 4: Closure of the Mucosal Entry

The mucosal entry site is sealed with endoscopic clips to prevent leakage.

If the opening is large, endoscopic suturing devices or fibrin glue may be used.

Complications:

Perforation

Bleeding

Submucosal Tunnel Collapse

Pneumomediastinum & Subcutaneous Emphysema

Esophageal or Gastric Leak

Esophageal or Gastric Stricture

Delayed Bleeding

Recurrence

References

Submucosal tunneling endoscopic resection: An effective and safe therapy for upper gastrointestinal submucosal tumors originating from the muscularis propria layer – PMC

References

Submucosal tunneling endoscopic resection: An effective and safe therapy for upper gastrointestinal submucosal tumors originating from the muscularis propria layer – PMC