Rat model of anal sphincter injury and two approaches for stem cell administration

Figure 1 Sphincter anal injury model. A: An arciform 10-mm to 15-mm anterior perianal incision (3 mm to 5 mm from the anal verge) was performed; B: Adipose tissue was dissected sideways to expose 20 mm of conduit until visualization of the thin, darker line of the external sphincter was achieved (arrow); C: An incision was made in the muscular layer until submucosa herniation, then submucosal dissection progressed in a longitudinal fashion, downward (until the anal verge or near the marking stitch) and upward (until 10 mm had been completed); D: Final aspect of sphincter section.