Introduction and hypothesis: The arcus tendineus fascia pelvis (ATFP) and arcus tendineus levator ani (ATLA) are elements of anterior vaginal support. This study describes their geometry in women with unilateral levator ani muscle defects and associated "architectural distortion."
Methods: Fourteen subjects with unilateral defects underwent MRI. 3D models of the arcus were generated. The locations of these relative to an ilial reference line were compared between the unaffected and affected sides.
Results: Pronounced changes occurred on the defect sides' ventral region. The furthest point of the ATLA lays up to a mean of 10 mm (p = 0.01) more inferior and 6.5 mm (p = 0.02) more medial than that on the intact side. Similarly, the ATFP lays 6 mm (p = 0.01) more inferior than on the unaffected side.
Conclusions: The ventral arcus anatomy is significantly altered in the presence of levator defects and architectural distortion. Alterations of these key fixation points will change the supportive force direction along the lateral anterior vaginal wall, increasing the risk for anterior vaginal wall prolapse.