Anatomy of the obturator region: relations to a trans-obturator sling

Our objective was to determine the relationships between a trans-obturator sling and anatomic structures within the obturator region. The obturator regions of six cadavers were dissected and distances from the mid-point of the ischiopubic ramus to the muscles, nerves, and vessels of the region were measured. A trans-obturator sling was placed and distances from the device to the same anatomic structures were determined. Four additional cadavers were dissected to determine the device route of passage. The obturator canal is on average 4.4 cm from the midpoint of the ischiopubic rami. The trans-obturator sling passes on average 2.4 cm inferior-medial to the obturator canal. The anterior and posterior divisions of the obturator nerve are on average 3.4 and 2.8 cm, respectively, from a passed trans-obturator device. The device passed on average 1.1 cm from the most medial branch of the obturator vessels. Vascular and nerve structures are within 1–3 cm of the path of any device passed through the obturator foramen. A trans-obturator sling risks injury to these structures, although the small caliber of the vessels and the confined space in which they would bleed make the consequences of injury uncertain.Editorial Comment: The authors performed anatomic dissections in fresh frozen cadavers to better understand the anatomy faced during the performance of a transobturator sling procedure. Since this anatomy has not been critically analyzed by the vast majority of pelvic surgeons, it is important for the practicing pelvic surgeon to attain a very clear image of the vascular and neurologic relationships in this area. The dissections were performed with the patients in high lithotomy position. Therefore, there is great clinical value to these dissections. However, the surgeon must also realize that a significant degree of variability exists, especially as related to vascular anatomy. This has implications for the safe performance of this novel approach to stress incontinence