No Sutures, Just Magnets: A Paradigm Shift in Colocolic Anastomosis for Malignant Rectosigmoid Strictures

Case

Magnetic compression anastomosis (MCA) is an emerging technique for managing enteroenteral, bilioenteric, and biliobiliary tract anastomosis.[1] [2] [3] MCA is a minimally invasive technique, often performed through laparoscopic, endoscopic, or combined laparoendoscopic approaches.[3] [4] The procedure involves placing two cylindrical or circular rare earth magnets (parent and daughter) on either side of a stenotic digestive segment, facilitating gradual compression anastomosis. Despite efficacy, the use of MCA is limited by unavailability of dedicated magnets and accessories to deploy the magnets. Here, we report an easy method of creating an MCA for the management of malignant rectosigmoid stricture.

A 45-year-old male, presented with progressive difficulty in passing stools over 3 months. Initially experiencing constipation, his symptoms worsened, prompting further evaluation. Blood tests revealed anemia and elevated carcinoembryonic antigen levels. Colonoscopy showed a rectal mass 9 cm above the anal verge causing severe luminal narrowing. Biopsy from mass confirmed poorly differentiated adenocarcinoma. Contrast-enhanced computed tomography showed circumferential wall thickening at the rectosigmoid junction measuring approximately 6 cm, with metastatic spread to the liver and lungs. He was diagnosed with stage IV colorectal cancer and started on chemotherapy.

Two months into treatment, he developed subacute intestinal obstruction with a transition zone at the rectosigmoid junction. He declined a diversion colostomy and was referred for palliative luminal stenting. However, severe luminal narrowing and angulation prevented the guidewire passage across the stricture. Following multidisciplinary discussion, MCA was considered as a novel alternative.

For the procedure, two neodymium magnets (2.5 cm diameter, 2 mm thickness, with a central hole) were used. A magnet larger than 2 cm carries a potential risk of impaction at anatomical narrowings such as the pylorus or ileocecal valve. This was carefully considered during the planning phase of the procedure. The patient first swallowed the proximal magnet under observation, ensuring no adverse reactions. He was closely observed and advised to keep distance from any kind of metals. Daily abdominal X-rays tracked its progression, and after 7 days, it reached the proximal stricture site. The distal magnet was then placed manually into the rectum and then pushed with a colonoscope till the stricture. Following little advancement, the proximal magnet attracted the distal magnet immediately. Alignment of magnets was confirmed on fluoroscopy. After 1 week, sigmoidoscopy revealed the formation of a new tract through the stricture, with spontaneous migration of magnets. Colonoscope (CF-190L, Olympus, Tokyo, Japan) could be negotiated across the de novo anastomosis into proximal lumen ([Fig. 1A–I]) ([Video 1]).

Video 1 Video demonstrating colocolic anastomosis by magnetic compression anastomosis in patients with metastatic rectosigmoid strictures.

Fig. 1 (A–I) Magnetic compression anastomosis for malignant rectosigmoid stricture. (A) Contrast-enhanced computed tomography (CECT) abdomen (sagittal) section showing growth causing tight stricture at the rectosigmoid region. (B) Colonoscopy showed severe luminal narrowing at the rectosigmoid junction. (C) Neodymium magnets (2.5 cm diameter, 2 mm thickness, with a central hole) were used. (D) Patient was asked to swallow one magnet. Progression of magnet across the gastrointestinal lumen was observed with daily X-ray abdomen. (E) On 7th day, the distal magnet was placed manually and pushed with a colonoscope. Fluoroscopy showed magnets are well apposed to each other. (F) Colonoscopy view of distal magnet. (G) Spontaneous migration of magnets observed at 1 week with the formation of colocolic anastomosis. (H) Colonoscopic view of anastomosis with ulceration. (I) Colonoscope (adult) could be negotiated across the de novo anastomosis in proximal lumen.

Patient is asymptomatic at 2 months of follow-up. Fibrosis at MCA usually occurs at 6 to 8 weeks and it may lead to restenosis requiring dilatation.[3] Additionally, the possibility of narrowing of the anastomotic site due to tumor progression cannot be ruled out. However, in this case, the fistulous tract was formed adjacent to the tumor, and not through the tumor. This may have contributed to the sustained patency of the tract and the patient remaining asymptomatic at the 2-month follow-up. Additionally, he was maintained on a soft, low-residue diet, and systemic chemotherapy (CAPOX regimen) was continued, which may have contributed to local tumor control and reduced the risk of early reobstruction. Patient has been called for follow-up at 4 months for assessment of symptoms and anastomotic site.

Practical implications for endoscopists:

• MCA offers a minimally invasive alternative for managing metastatic rectosigmoid stricture when conventional stenting is not feasible or the patient is high risk for surgery.

• MCA is a useful technique for rectosigmoid or left-sided stricture. However, it can be challenging for high-end or proximal stricture, as there is no dedicated device to deliver the distal magnet to the stricture site.

• Larger magnet (> 2.5 cm) may become impacted at the pylorus or ileocecal valve. A through preprocedural risk assessment is essential, and fluoroscopic monitoring should be performed following ingestion to track the progression.

• Patients with magnets in situ should be kept away from metal objects, and magnetic resonance imaging should be avoided during this period.

• The safety and efficacy of MCA needs to be evaluated in further studies with large sample sizes and longer follow-up periods.

Funding

None.

Publikationsverlauf

Artikel online veröffentlicht:
13. Mai 2025

• References

• 1 Kamada T, Ohdaira H, Hoshimoto S. et al. Magnetic compression anastomosis with atypical anastomosis for anastomotic stenosis of the sigmoid colon: a case report. Surg Case Rep 2020; 6 (01) 59
• 2 Chavan R, Solanki R, Patel M, Gandhi C, Prajapati M, Rajput S. Magnetic compression anastomosis of post-cholecystectomy benign biliary stricture using modified accessories (with video). Indian J Gastroenterol 2024; 43 (05) 1068-1071
• 3 Kamada T, Ohdaira H, Takeuchi H. et al. New technique for magnetic compression anastomosis without incision for gastrointestinal obstruction. J Am Coll Surg 2021; 232 (02) 170-177.e2
• 4 Graves CE, Co C, Hsi RS. et al. Magnetic compression anastomosis (magnamosis): first-in-human trial. J Am Coll Surg 2017; 225 (05) 676-681.e1