Endoscopic "no hole" full-thickness biopsy of the stomach to detect myenteric ganglia

Abstract

Background: The etiology of several common gastric motility diseases remains largely unknown. Gastric wall biopsy specimens that include the muscularis propria to evaluate the enteric nervous system, interstitial cells of Cajal, and related cells are essential to promote our understanding of the pathophysiologic mechanisms. On the basis of our previous work, a double EMR technique provided sufficient tissue to identify myenteric ganglia. A serious limitation to the technique was the resultant gastric wall perforation after tissue resection. The optimal procedure would seal the gastric wall defect before tissue resection, eliminating the risk of peritonitis.

Objectives: The aims of this study were to (1) determine the technical feasibility and reproducibility of a full-thickness gastric biopsy by use of a novel double EMR technique without creating a perforation ("no hole") and to (2) determine safety of the procedure.

Design and interventions: Preclinical study of 6 pigs. Each animal underwent a "no hole" double EMR survival procedure. To prevent perforation, detachable endoloops and prototype T-tag tissue anchors were placed before resection. At 2 weeks repeat endoscopy was performed followed by necropsy.

Main outcome measurements: Hematoxylin-eosin staining was used to determine which muscle layers were included in the resected specimen, and an antibody to neuronal nitric oxide synthase was used to visualize myenteric ganglia in the sample. Technical feasibility, reproducibility, and safety of the procedure were evaluated.

Results: Full-thickness gastric biopsy specimens were obtained from all animals without overt perforation. There were no procedural complications. Histologic examination showed muscularis propria with all layers of muscle present, and immunochemical studies demonstrated myenteric ganglia in all tissue samples. Four animals had an uneventful clinical course, and repeat endoscopy at week 2 showed ulceration with stellate fibrosis. Necropsy showed mild localized adhesions. Two animals were killed at days 3 and 6, respectively, because of suspected peritonitis. At necropsy, delayed perforations at the resection sites were noted with displaced endoloops and tissue anchors.

Conclusion: This study explored the concept of obtaining deep muscle wall biopsy specimens with use of a unique approach of resection without perforation. The novel "no hole" double EMR technique was technically feasible and reproducible with sufficient tissue obtained to identify myenteric ganglia. However, there was a high delayed perforation rate associated with displaced endoloops and tissue anchors. On the basis of this early experience, improved safety data may be anticipated with future studies using improved tissue closure devices.

FIGURE 1

FIGURE 1A: EMRC performed without a protective submucosal cushion FIGURE 1B: Exposed muscle layer suctioned into EMRC cap while the endoloop was gently released and tightened around the pseudopolyp. FIGURE 1C: Second endoloop and prototype T-tag tissue anchors are positioned around the base and adjacent to the pseudopolyp respectively. FIGURE 1D: Pseudopolyp resected by snare electrocautery. FIGURE 1E: Resection site further closed by tightening (opposing) prototype T-tag tissue anchors.

FIGURE 1

FIGURE 1A: EMRC performed without a protective submucosal cushion FIGURE 1B: Exposed muscle layer suctioned into EMRC cap while the endoloop was gently released and tightened around the pseudopolyp. FIGURE 1C: Second endoloop and prototype T-tag tissue anchors are positioned around the base and adjacent to the pseudopolyp respectively. FIGURE 1D: Pseudopolyp resected by snare electrocautery. FIGURE 1E: Resection site further closed by tightening (opposing) prototype T-tag tissue anchors.

FIGURE 2

Endoloop (A) attached around the outer aspect of the distal end of the straight EMRC cap with adhesive surgical tape securing the catheter (B) of the endoloop to the endoscope outer sheath.

FIGURE 3

Endoscopic image showing muscle wall pseudopolyp with two endoloops at the peusopolyp base.

FIGURE 4

Endoscopic image of resection site closed by prototype T-tag tissue anchors.

FIGURE 5

Hematoxylin and Eosin (H&E) staining of tissue showing the muscularis propria and myenteric plexus region. H&E stained section of the full thickness muscle resection showing the presence of the circular muscle (CM), myenteric plexus region (MP), and longitudinal muscle (LM). Scale bar = 100 µm

FIGURE 6

Tissue showing anti-nNOS immunopositive myenteric ganglia. nNOS immunoreactivity showing the presence of nNOS positive neurons in the sample indicating that the myenteric plexus was present in the muscle resection. Scale bar = 20 µm.

FIGURE 7

Endoscopy at week 2 demonstrating ulceration with stellate fibrosis and retained T-tag tissue anchors.

FIGURE 8

Necropsy showing localized adhesions between gastric wall and adjacent small bowel.