Anatomic relationships of infracoccygeal sacropexy (posterior intravaginal slingplasty) trocar insertion

Objective The purpose of this study was to describe the distances of the major bony, vascular, neurologic, and visceral structures to the path of the infracoccygeal sacropexy trocar and to determine the point of trocar entry into the vagina. Study design Infracoccygeal sacropexy trocars were inserted bilaterally into 6 fresh frozen cadavers. Dissection was performed and the maximal length of the vagina, ischiorectal fossa, and pararectal spaces were measured bilaterally. Mean distances with 95% CIs to important anatomic structures were made from fixed points along the trocarʹs path. Results The path of the trocar began dorsal and lateral to the anus, passed through the ischiorectal fossa, iliococcygeus muscle, into the pararectal space, and into the posteriolateral vagina. Along this course, the mean distance (95% CI) to the pudendal vessels at the exit of Alcockʹs canal was 2.8 cm (2.1 to 3.4 cm) and rectum was 0.5 cm (0.2 to 0.9 cm). The closest inferior rectal vessel was 0.1 cm (0 to 0.3 cm). In the pararectal space, the mean distance to the ischial spine was 2.6 cm (1.7 to 3.5 cm). In 12 of 12 trocar passages, the inferior rectal branches of the pudendal artery and the rectum were within 1 cm or less of the trocar. The mean distance of trocar entry into the vagina was only 4.8 cm (4.3 to 5.4 cm) proximal to the hymenal ring compared with a mean total vaginal length of 8.7 cm (8.0 to 9.3 cm). Conclusion This anatomic study suggests that the rectum and the inferior rectal branches of the pudendal neurovascular bundle may be at risk of injury during infracoccygeal sacropexy trocar placement. Additionally, this procedure appears to provide support to the mid-posterior vaginal wall, not the vaginal apex.