Endoscopic full-thickness biopsy of the gastrointestinal wall: a new device tested in a long-term animal survival study

Introduction: Full thickness biopsy (FTB) of the gut is necessary for the diagnosis of enteric neuromuscular diseases (ENMD). To date FTB is only done by surgery. Endoscopic biopsy methods would enable easier diagnosis of ENMD and facilitate research of other diseases. Aims: To test the ability of a novel prototype FTB-device, to obtain ≈1cm in diameter full-thickness gut tissue to provide appropriate histology for the diagnosis of ENMD; 2) To determine whether the FTB-device would damage adjacent tissue in the peritoneal cavity and whether endoscopic closure of the defect with t-tags is sufficient. Methods: In 12 animals 2 FTB each were taken from the anterior (n=6) and posterior (n=6) gastric walls with the new endoscopic device and retrieved for histology. The defects were closed with endoscopic t-tags. Post intervention a laparoscopy was performed to inspect the resection site for any damage caused. Animals were kept alive for 2 weeks, thereafter autopsy was carried out to evaluate late complications. Results: All FTBs were successfully performed. Retrieval of the specimens was possible in 34/36 samples. Median time to perform FTB was 8.7min (range 5.8–13.3), for defect closure 19.8min (range:8.6–29). T-tag closure was successful in all cases. No major complications were seen. Post-procedure laparoscopy proved a minor defect at the surface of the liver, but no other lesions. The FTB samples were median 7.8mm in diameter with little evidence of serious edge damage. Histology proved the presence of neurons in the submucosal and myenteric plexus. The circular and longitudinal muscle layers were of very good quality for analysis. At autopsy, the scars of the FTB appeared to have healed well. No abscesses or other abnormalities were seen. Conclusion: Using an innovative endoscopic FTB-device we have shown that FTB was possible, successful and provided plenty of material when performed in the anterior/posterior wall of the stomach. Histology proved the tissue to be excellent and appropriate for ENMD diagnosis. It also showed that there was potential for possible damage, when performed at the posterior side. Further studies including other areas of the gut such as the small bowel and colon will be necessary to prove the clinical importance of this new method.