Minimally Invasive Full-Thickness Resection of a Non-Lifting Adenoma in an Ulcerative Colitis Patient Using OVESCO: A Case Report.

Introduction
Endoscopic full-thickness resection is an innovative approach for managing non-lifting adenomas and other difficult colorectal lesions. The full-thickness resection device (FTRD; Ovesco, Tübingen, Germany) is an over-the-scope system approved in Europe since 2014 for lower GI tract full-thickness resection [1]. It has been effectively used for lesions at the appendiceal orifice, non-lifting polyps, submucosal lesions, and fibrotic lesions [2].
Prior to mounting the FTRD onto the scope, initial marking was performed around the lesion using the provided probe with soft coagulation. The FTR is then mounted to the tip of the colonoscope, which is advanced to the lesion. The lesion was then grasped with the provided grasper and gently pulled into the cap, minimizing suction as this may compromise extra-colonic structures. Once the lesion is positioned entirely within the cap, the OTSC clip is released by turning the hand wheel. The lesion is then resected by closing the preloaded snare while applying Endo Cut Q current, following a technique similar to conventional EMR. The resected tissue is retrieved within the cap, held by the grasper, and the scope is withdrawn [2]. The OVESCO system has demonstrated safety and efficacy in the general population, with a technical success rate of 88–89.5%, an adverse event rate of 9.9–13%, and perforation rates of 0–2% [3–5]. However, its efficacy and safety in inflammatory bowel disease (IBD) remain unstudied.
Patients with longstanding IBD have a 2–3 times higher risk of colorectal cancer (CRC) compared to the general population [6]. Early meta-analyses estimated a cumulative CRC risk of 2% at 10 years, 8% at 20 years, and 18% at 30 years in UC patients [7]. Chronic inflammation frequently leads to submucosal fibrosis, complicating resection with EMR and ESD due to poor lesion lifting [8, 9]. Consequently, CRC remains a major cause of mortality and a common indication for colectomy in IBD patients [10].
When endoscopic resection is unsuccessful or incomplete, colectomy is often recommended [8]. However, this may not be feasible for elderly or frail patients with multiple comorbidities, who also often prefer to avoid a stoma. Segmental colectomy is a possible alternative, though outcomes in IBD patients are concerning. A retrospective case series found that 16.7% of IBD patients undergoing segmental colectomy for non-endoscopically resectable neoplasia experienced severe complications (Clavien-Dindo class III–V), with 8.3% developing early colitis, 80% developing late colitis, and 11.1% ultimately requiring completion proctocolectomy [11]. This case highlights the potential of FTRDs as a minimally invasive alternative for IBD-related dysplasia when fibrosis prevents submucosal lifting.

Case Report
The patient is a 76-year-old male with a 30-year history of UC, which has remained stable with Mezavant 4.8 g daily, achieving histological remission on biopsy. He was previously on Imuran, discontinued 4 years ago. His medical history includes diabetes, ischemic heart disease, and stage 3A chronic kidney disease.
During routine surveillance in 2023, a 25 mm dysplastic lesion was detected at the splenic flexure (approximately 50 cm from the anal verge) using chromoendoscopy. An interventional gastroenterologist attempted EMR with gelofusine injection, but only a small fragment was removed as most of the polyp failed to lift. Histopathology confirmed a tubulovillous adenoma.
The patient was referred for ESD, but the lesion appeared poorly defined, with 3–4 cm of congested, irregular mucosa, and the adenoma itself measuring 25 mm. Near-focus narrow-band imaging suggested areas of high-grade dysplasia. However, ESD was abandoned due to significant submucosal fibrosis and high perforation risk (Fig. 1).
Given the patient’s stable UC and lack of histological activity or dysplasia elsewhere, the polyp was considered a traditional adenoma rather than colitis-associated dysplasia. Given the incomplete resection, subtotal colectomy was considered. After consultation with a colorectal surgeon, both proctocolectomy and segmental resection were discussed, but due to the patient’s high surgical risk and preference to avoid a stoma, colectomy was not pursued.
A multidisciplinary team decided to attempt full-thickness resection using the OVESCO system (Fig. 2). Complete resection was achieved, with histopathology confirming a tubular adenoma with low-grade dysplasia and clear margins (Fig. 3). Due to electrocautery by Endo Cut Q, the circumferential markings were partially destroyed, making all circumferential markings difficult to identify. The patient recovered uneventfully without complications. A repeat colonoscopy with biopsies of the polypectomy site has confirmed that no residual polyp was left over.

Discussion
This case highlights the complexities and innovative management strategies involved in treating colorectal lesions in longstanding IBD. In UC patients, heightened CRC risk necessitates ongoing surveillance [7, 8]. Chronic inflammation often leads to submucosal fibrosis, making resection via EMR or ESD technically challenging [9].
Although colectomy remains the standard when endoscopic resection is not feasible, it carries notable morbidity, particularly in older patients or those with significant comorbidities [12]. Segmental resection also presents risks, including anastomotic leakage [11].
Underwater EMR (u-EMR) is a technique, which can be used as an alternative to traditional EMR; in lieu of submucosal injection, u-EMR incorporates immersion of the entire lumen in water and snare resection without submucosal injection. Although not typically regarded as a salvage approach in cases of submucosal fibrosis, u-EMR can still be effective even when fibrosis is present.
The OVESCO FTRD offers a novel, minimally invasive alternative for high-risk IBD patients as it can capture and remove fibrotic submucosal layers, allowing full-thickness resection and potentially reducing recurrence [1]. In this case, the OVESCO system successfully achieved complete adenoma resection with clear histological margins, preserving colonic function and eliminating the need for a stoma.
Despite its advantages, the FTRD system has certain limitations and challenges. The outer diameter is 21 mm, which can be difficult to advance to the lesion, especially if located in the right colon, or in patients with stenosing diverticular disease. Device failures with the FTRD system have also been reported, including clip or snare malfunctions that may lead to perforation or incomplete resection. Andrisani et al. [13] observed an 11% failure rate in FTRD procedures for colorectal lesions.
If the integrated snare fails after clip deployment, a conventional snare may be used; however, this can increase the risk of thermal injury and delayed perforation due to its proximity to the clip. The integrated snare minimizes this risk by maintaining a safe, fixed distance from the clip. Cases of clip mis-deployment and incomplete OTSC closure – particularly in the transverse colon – have resulted in mucosal leaks, often managed successfully with an additional OTSC. In rare instances, delayed closure has led to peritonitis.
A multicentre Italian study reported technical failure in 77 of 750 patients, mainly due to non-cutting snares (53%), clip mis-deployment (31%), and cap misplacement (16%) [14]. Use of a guidewire may assist in accurate cap positioning when misplacement is anticipated.
Taken together, these findings support the OVESCO FTRD system as a viable option for non-lifting polyps in IBD patients, particularly when surgical approaches are limited by age or comorbidities. To the best of our knowledge, this is the first account of its use in Australasia. Further investigation is warranted to evaluate long-term outcomes, recurrence rates, and overall safety in this specific patient population. The CARE Checklist has been completed by the authors for this case report, attached as online supplementary material (for all online suppl. material, see https://doi.org/10.1159/000548329).

Statement of Ethics
Ethical approval is not required for this study in accordance with local or national guidelines. Written informed consent was obtained from the patient for publication of the details of their medical case and any accompanying images.

Conflict of Interest Statement
The authors have no conflicts of interest to declare.

Funding Sources
This case report was not supported by any sponsor or funder.

Author Contributions
F.Y. Pan wrote the article, revised it for intellectual content, and is the guarantor. V. Kariyawasam and S. Gupta obtained consent, provided endoscopic images, and revised the article for intellectual content. R. Leong revised the article for intellectual content. T. Fuchs selected histology images and provided descriptions.