EP700 - Anastomotic Strictures After Left-Sided Colectomy Without a Protective Stoma: A Cohort Evaluation of Dehydrated Human Amnion/Chorion Membrane Use

Purpose/Background: Anastomotic stricture is a clinically significant complication following left-sided colectomy (LSC) negatively impacting quality of life, often requiring repeated endoscopic dilation or reoperation. Stricture rates are influenced by factors such as stoma creation, age, anastomotic leakage, radiotherapy, stapler selection, and surgical technique. In patients undergoing elective LSC, reported stenosis rates range from 2% to 17.6%, reflecting substantial variability influenced by patient comorbidities, duration of follow-up, and methods of assessment. Anastomotic stricture is caused by a complex interplay of fibrosis, inflammation, and ischemia with fibrosis being the primary pathological driver. Dehydrated human amnion/chorion membrane (DHACM) allografts are non-viable cellular tissue grafts derived from donated placentas. Rich in cytokines, growth factors, and tissue inhibitors of metalloproteinases, DHACM provides an immune-privileged biologic matrix that supports wound healing and tissue regeneration. Preclinical studies, including chemotherapy- and radiation-compromised models, demonstrate that amniotic membranes enhance anastomotic healing by strengthening tissue, promoting angiogenesis, stimulating fibroblast and collagen activity, and reducing inflammation, adhesions, and fibrosis. This study reports real-world outcomes of anastomotic stricture after DHACM application around the colorectal anastomosis in patients undergoing LSC without a protective stoma.

Methods/Interventions: Retrospective chart review of consecutive adult patients who received DHACM directly applied to the colorectal anastomosis during a LSC without a protective stoma between 01JAN2016 to 30JUN2024. Primary endpoint was anastomotic stricture formation confirmed by colonoscopy from 30 days post-operative up to 7 years. Secondary endpoints included anastomotic leak and 30-day readmission. The study was granted an IRB exemption (WCG IRB).

Results/Outcomes: 373 consecutive patients received DHACM applied to a colorectal anastomosis during a LSC were evaluated, Figure 1. During the follow up period, two patients (0.5%) were diagnosed with a stricture. Both anastomotic strictures were asymptomatic and identified on follow-up colonoscopy at 402 and 548 days post-operative respectively. The strictures were resolved with dilation and follow-up evaluations confirmed open anastomosis with intact mucosa and staple lines. Regarding secondary endpoints, there were 9 (2.4%) anastomotic leaks and 18 (4.8%) all-cause hospital readmissions within 30 days of colectomy.

Conclusion/Discussion: In this cohort, DHACM use was associated with at least a 4-fold reduction in anastomotic strictures (0.5%) compared with historical benchmark rates of 2%-17.6%. When compared to the lower end of this range, the difference was statistically significant (p= 0.04, one-sample proportion test). Animal studies suggest this benefit could stem from modulation of inflammation and immune response, thereby promoting a healing environment. Of note, prior anastomotic leak is a strong predictor of later stricture formation, and in the DHACM cohort the anastomotic leak rate was also very low compared to historical controls, which may have contributed to the observed stenosis outcomes. Additional studies are warranted to confirm these results and establish the role of DHACM in colorectal surgery as well as the prevention of stricture formation.

Figure 1. Patient Demographics and Endpoints (n= 373)