ANATOMIC RELATIONSHIPS OF INFRACOCCYGEAL SACROPEXY (POSTERIOR INTRAVAGINAL SLINGPLASTY) TROCAR INSERTION

JE Jelovsek, AI Sokol, MD Walters, MD Barber

The Cleveland Clinic Foundation, Cleveland, OH

OBJECTIVE: 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.

MATERIALS AND METHODS: Infracoccygeal sacropexy trocars were inserted bilaterally using the manufacturer’s recommended technique into six fresh frozen cadavers who were placed in the high lithotomy position.  After trocar placement, dissection was performed from the abdominal, perineal, and vaginal approaches.  The maximal length of the vagina, ischiorectal fossa, and pararectal spaces were measured bilaterally in each cadaver.  Measurements to important anatomic structures were made from fixed points along the trocar’s path. Mean distances with 95% confidence intervals from important anatomic structures to the trocar were used to create a computer generated, three-dimensional model of the trocar’s in-situ path.

RESULTS:  The path of the trocar begins dorsal and lateral to the anus, passes 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 gluteus maximus is 0.6 cm (-0.2 - 1.4cm), pudendal vessels at exit of Alcock’s canal 2.8cm (2.1 - 3.4cm), and rectum 0.5cm (0.2 - 0.9cm). The mean distance from the trocar to the closest inferior rectal vessel was 0.1cm (-0.1 - 0.3cm). In the pararectal space the mean distance of the trocar (95% CI) to the ischial spine was 2.6cm (1.7 - 3.5cm), uterine artery 3.5cm (2.7 - 4.4cm), ureter 3.5cm (2.8 - 4.2cm), and internal iliac artery 6.4cm (4.9 - 7.9cm).  The mean distance of passage in the ischiorectal fossa was 5.9cm (4.9 - 6.9cm), and pararectal space 1.6cm (0.7 - 2.4cm).  In 12 of 12 trocar passages, the inferior rectal branches of the pudendal artery and the rectum were within one centimeter or less of the trocar. The mean total vaginal length from the hymen was 8.7 cm (8.0 - 9.3 cm). The mean distance of trocar entry into the vagina was only 4.8 cm (4.3 - 5.4cm) proximal to the hymenal ring. 

CONCLUSIONS: This anatomic study suggests that the rectum and the inferior rectal branches of the pudendal artery 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.

Key Words: anatomy, vaginal vault suspension, pelvic organ prolapse, infracoccygeal sacropexy, posterior intravaginal slingplasty.

Disclosure - Consultant: M.D. Walters, American Medical Systems.