A colonoscopic overtube system that creates a ‘therapeutic zone’ and permits retraction facilitates endoscopic submucosal dissection, was associated with fewer deep bowel wall injuries and instrument exchanges, and required less lifting solution vs classic endoscopic submucosal dissection in an ex vivo bovine model

Abstract

Introduction

Endoscopic submucosal dissection (ESD) is the ‘gold standard’ for large flat polyps; nevertheless, the rate of adoption in the USA is low. In ESD, the polyp is ‘surgically’ detached with a needle knife after a submucosal lift; gravity and the dissection cap are used for retraction. ESD would be easier if active retraction were possible. In an ex vivo bovine colon model, this study assessed an overtube system (Boston Scientific ORISE Tissue Retraction System, TRS) that permits retraction and creates ‘an operative field’ for removal of rectal/sigmoid lesions.

Method

Classic ESD (C-ESD) was compared to TRS-facilitated ESD (TRS-ESD). Cleaned/preserved bovine large bowel was used, and two 2-cm ‘lesions’/colon were branded onto the mucosal surface 25 and 35 cm from the anus. Submucosal saline lifts were made using a thin catheter and a standard needle knife. We tracked case length, number of instrument exchanges (to refresh lift), the volume of lift solution, the fullness of resection, and deep muscle injuries.

Results

Fifty ESDs were carried out in 25 colons (25 C-ESD, 25 TRS-ESD). Complete resections were noted in all cases. The TRS method required fewer instrument exchanges (median 5) vs C-ESD (median 9, p < 0.0001) and less lift solution (median 39 ml) than the C-ESD cases (median 55 ml, p = 0.0003). TRS-ESD was associated with fewer deep muscle injuries (median 2) than C-ESD (median 3, p = 0.0191). Finally, the TRS group’s median case length (34.5 min) was shorter than that of C-ESD (41 min, p = 0.0543).

Conclusion

The TRS system provides retraction and facilitates ESD regarding the number of lift injections, the volume of lift solution needed, and avoidance of muscle injuries. Of note, there is an apparent TRS learning curve, and the device mandates a distal-to-proximal approach and initial 360 degree mucosal incision. Further study is warranted.