Underwater in-block R0 intermuscular dissection of a T1b rectal adenocarcinoma in a patient with decompensated cirrhosis with the prophylactic use of recombinant factor VII. In this case, we describe a 60-year-old patient with decompensated cirrhosis who was found to have a 2-centimeter rectal cancer with submucosal invasion as seen on biopsy and EUS. The case was presented at selection committee. Patient was denied listing and deemed too high risk for surgical resection. Given known submucosal invasion, the decision was made to proceed with intermuscular dissection in order to maximize the chance of in-block R0 resection. On the left side of the screen, we have traditional ESD depicting a resection plane between the submucosa and muscularis propria. On the right, we can appreciate EID, where the resection plane lies between the circular and longitudinal muscle fibers of the muscularis propria. In this case, we describe the technique, equipment, and rationale for proceeding with intermuscular dissection as opposed to conventional ESD or surgical consideration. Administration of FFP may not be feasible due to volume constraints. Recombinant factor VII does not cause hypervolemia. There have been case reports describing the prophylactic use of factor VII in polypectomy and cirrhosis. However, factor VII's use for EID has never before been described. Given our patient had decompensated cirrhosis with rectal varices, a multidisciplinary decision was made to administer a prophylactic dose of factor VII prior to EID. We used a standardized dose of 40 micrograms per kilogram rounded to 4 milligrams given just prior to EID. Ultimately, the correction of coagulopathy in cirrhosis is at the discretion of the proceduralist or surgeon. Here, we can see the T1b rectal cancer under retroflexion. We start with marking around the lesion. We use a 23-gauge Carlock needle mixed with saline, epi, indigo carmine, and endoclot to lift the lesion. We use the dual knife J to perform mucosotomy. The edges are trimmed thoroughly in order to prepare for intermuscular tunneling. After complete circumferential mucosotomy, the cap is switched to a distal tapered cap to initiate the procedure. The lesion is fully immersed in saline, and the dual knife is used to dissect the submucosa and expose the circular layer of the muscularis propria. We then dissect beyond the circular fibers and enter the intermuscular space above the longitudinal fibers. Once the intermuscular space is accessed, the plane is lifted for continued dissection of the intermuscular space. Vessels can be coagulated with closed dual knife using spray coagulation. For larger vessels, coag graspers are used to coagulate the vessels using soft coag. Underwater dissection allows for improved visualization and localization of vessels, as maintaining hemostasis is critical given decompensated cirrhosis. Once the oral side of the pocket is reached, the patient's position was changed to allow for traction via gravity and the tunnel creation was completed. The lateral sides of the tunnel are then released using the dual knife on one side. The other side of the tunnel is released using the IT nano knife and the lesion is removed in block. Once the procedure is completed, you can see the selective myotomy of the circular muscle fibers and the remaining longitudinal fibers after endoscopic intermuscular dissection. All visible vessels were coagulated with co-ab graspers and the defect was treated. Overstitch was used to close the defect. Final inspection of the defect shows excellent closure immediately proximal to the dentate line. The final specimen is pinned and demonstrates a layer of circular fiber expected from endoscopic intermuscular dissection. A prospective cohort study by MOONS published in Endoscopy in 2022 describes the rationale and efficacy of EID. This study, which included 67 patients with deep submucosal invasive cancer, defined as a depth of invasion greater than 1,000 microns, showed a 96% technical success rate and an 81% rate of R0 resection. Curative resection was described at 45%. There were no deaths and no major complications. Notably, patients who underwent both curative and non-curative margin-negative resection who were followed with surveillance showed a recurrence rate of 0 at 6 months and 1 out of 28 patients at the 12-month interval. The single episode of recurrence occurred in a non-curative resection, and once identified, they were able to undergo curative surgical resection. This supports the use of EID as opposed to full thickness resection, as EID will not influence the outcome of total mesorectal excision should it become necessary. The patient was represented and accepted at selection committee and ultimately underwent uncomplicated liver transplant. EID should be considered in T1b rectal cancers as an alternative to ESD and EFTR when technically feasible as to increase the chance of R0 resection and decrease any future surgical complications that may arise. The prophylactic use of recombinant factor VII should be considered in cirrhotic patients undergoing EID, however, more research is needed to establish clear guidelines on the use of recombinant factor VII in these scenarios.

intermuscular dissection

rectal adenocarcinoma

recombinant factor VII

underwater approach

R0 resection