Anatomical structures of the obturator foramen and its importance for pelvic interventıons

Abstract

Background: In clinical scenarios such as pelvic fractures, damage to the obturator neurovascular bundle, obturator neuropraxia, and mesh placement in patients with incontinence, preserving the anatomical structures related to the obturator foramen (OF) is crucial. This study aims to investigate the anatomical variations of the OF as a guide for identifying failure criteria and improving success parameters in clinical practice.

Methods: The OFs of one hundred adult dry pelvic bones were examined. Measurements were evaluated using ImageJ software. The morphology of the OF and the presence of bony projections on the inner surface of the foramen were assessed.

Results: The anterior-posterior length was 5.24 ± 0.8 cm on the right and 5.17 ± 0.87 cm on the left. The superior-inferior length was 4.69 ± 1.83 cm on the right and 4.66 ± 1.69 cm on the left. The anterior-posterior vertical angle was 98.21 ± 9.95° on the right and 98.48 ± 13.9° on the left; the superior-inferior horizontal angle was 90.7 ± 10.95° on the right and 97.56 ± 9.42° on the left. The OF was categorized into six distinct types: quadrilateral (23%), ellipsoid (22%), and oval (17%). The ellipsoid-type OF showed a greater anterior-posterior length compared to the other types, while the triangular-type OF exhibited a greater symphysis pubis length. Notably, bony projections on the anterior edge of the inner surface of the OF were observed in 33% of cases. Additionally, bony projections on the posterior edge of the OF were described for the first time.

Conclusion: In cases where OF is narrow and variable, and where bony projections are present on its inner surface, performing an osteotomy may help protect the obturator neurovascular bundle.

Keywords: Bony pelvis; Obturator foramen; Pubic arch.