Abstract: Abstract: Objective To evaluate the effects of unilateral extralevator abdominal-perineal excision (ELAPE) surgery and the ELAPE surgery on the pelvic floor detected by finite element analysis. Methods Three kinds of finite element mod⁃ el were developed: the intact model, ELAPE model and the unilateral ELAPE model. The maximal stress and stress distribu⁃ tions of each model under the same pressure were analyzed and compared. Results In the unilateral ELAPE model, non-le⁃ vator ani tissue’ s maximal stress on the levator ani reserved side was lower than that in ELAPE model, and was similar to that in the intact model. Its maximal stress on the excised side was lower than that in ELAPE model, and which was higher than that of intact model. Its maximal stress on the reserved side was lower than that of on the excised side. Conclusion Compared to the ELAPE surgery, the unilateral ELAPE surgery is able to reduce the stress of non-levator ani tissue on both sides, especially on the levator ani reserved side.

Key words: abdomen, perineum, pelvic floor, biomechanics, finite element analysis, ELAPE surgery