ENDOSCOPIC INTERMUSCULAR DISSECTION FOR THE LOCAL RESECTION OF RECTAL CANCER

Gastric fistula formation is a known complication of bariatric surgery. Many gastric fistulae can be managed endoscopically, however, it can be difficult to successfully treat chronic fistulae. New techniques such as cardiac septal occluders continue to add to the endoscopic arsenal for fistula closure. A drawback of cardiac septal occluders is their large diameter. Vascular plugs come in smaller diameters and can therefore be deployed into smaller fistulae. We present a video demonstration of vascular plug deployment for gastrointestinal fistulae closure.

Endoscopic Methods:
Our case series focuses on vascular plug deployment for management of gastro-bronchial and gastro-gastric fistulae that were refractory to traditional management (including over-the-scope suturing, through-the-scope helical tack placement, endoscopic internal drainage, and endoscopic diversion therapy). In our cases fistulae were small, measuring 3 mm to 4mm in diameter, respectively.

Vascular plug manufacturers recommend that the plug diameter should measure 50% larger than the target lumen. Thus, for both cases we chose to deploy a 6 mm by 6 mm vascular plug. The vascular plug is made of a nitinol mesh and is attached to a delivery wire via a screw attachment. Advancing or retracting the delivery wire advances or recaptures the vascular plug. Once in position, counterclockwise torque of the delivery wire unscrews the vascular plug and releases it. The vascular plug comes loaded on a 100 cm delivery wire, which prevents deployment through the endoscopic working channel. Therefore, we use a modified 10-7-5 biliary dilation catheter to deliver the vascular plug. The catheter is altered by modifying the distal tapered end to allow for plug deployment and then modifying the proximal end to accommodate the 100 cm delivery wire. These modifications also allow for the plug to be inserted into the catheter.

In our cases, pre-procedurally patients with gastro-bronchial and gastro-gastric fistulae reported significant coughing and reflux respectively. Vascular plug deployment in both cases was technically successful and clinically successful as both patients immediately had improvement in symptoms and a subsequent durable response.

Conclusion:
This case series highlights the use of vascular plug devices as feasible alternate endoscopic therapies for gastric fistulae closure where other established techniques have failed. In two cases of difficult-to-manage gastric fistulae, closure was achieved using vascular plugs and modified versions of available endoscopic tools. Both patients achieved symptomatic resolution and avoided the need for surgical intervention. Further study is needed to better analyze the potential benefits and limitations of these interventions as well as long-term clinical outcomes.

Background: Local excision is a potentially curative and organ-preserving option in rectal cancer with submucosal invasion. However, there are concerns regarding positive deep resection margins in submucosal approaches and disruption of the total mesorectal excision plane in full-thickness strategies. Here we present a step-by-step demonstration of endoscopic intermuscular dissection (EID) within the plane between the longitudinal and circular rectal muscle wall, which offers a high likelihood of achieving a negative vertical margin and accurate evaluation of invasion depth in situations where deep submucosal invasion is suspected or possible.

Case Presentation: A 31-year-old woman underwent a colonoscopy for evaluation of rectal bleeding and diarrhea. Colonoscopy demonstrated a 2 cm mass in the distal rectum with biopsies consistent with adenocarcinoma. Magnetic resonance imaging suggested a T1N0 lesion located 4 cm from the anal verge. After multidisciplinary discussion, en bloc endoscopic resection via EID was recommended for local control, pathological staging, and evaluation for risk of lymph node metastasis.

Endoscopic Methods: A solution of epinephrine, methylene blue, and saline was prepared for submucosal lifting. A transverse mucosal incision was made at the anal margin just above the dentate line to create a stable submucosal tunnel. Solution was then injected into the intermuscular plane, and the inner circular muscle layer was incised to enter the intermuscular space. Dissection of the intermuscular connective tissue was conducted in the oral direction until the endoscope was well beyond the oral margin of the lesion. The endoscope was then retroflexed, and the oral margin of the lesion was incised into the submucosa and intermuscular space until the tunnel was re-encountered. Finally, the lateral borders were undermined to release the specimen. No bleeding, full-thickness defects, or longitudinal muscle injury was observed. Pathology confirmed a pT1b, SM3, moderately-to-poorly differentiated, high-grade adenocarcinoma with negative margins. The patient was discharged same day and prescribed antibiotics for 7 days. Following multidisciplinary discussion at tumour board, the patient elected to undergo adjuvant chemoradiation to reduce her risk of recurrence in the regional lymph nodes.

Conclusions: By providing en bloc specimens while avoiding distortion of the total mesorectal excision plane, EID offers several benefits over conventional approaches for the local resection of T1 rectal cancers. A prospective study of 67 patients demonstrated high technical success and R0 resection rates of 96% and 81%, respectively, with no major adverse events. Future research is needed to delineate optimal procedural indications and the role of combinatorial adjuvant therapy to maximize EID’s curative potential.