Where do we place the sacrocolpopexy stitch? A magnetic resonance imaging investigation.

OBJECTIVES: Sacrocolpopexy presacral sutures are placed at or slightly above the sacral promontory without knowledge of the location of intervertebral discs. We used magnetic resonance imaging to assess the anatomic relationship of the sacral promontory to intervertebral discs.

METHODS: We reviewed spinal magnetic resonance images of women imaged at Loyola University Medical Center between January 2010 and February 2012. Sagittal T1 fluid-attenuated inversion recovery sequence images of the lumbosacral spine were used to identify the promontory as the most prominent point where S1 intersected with the superior anatomic structures. All measurements were obtained at the midline of the spinal cord.

RESULTS: The mean age of 73 study subjects was 59 years (range, 22-89 years). The promontory was an intervertebral disc in many women (53 [73%]); the remaining images confirmed a nondisc promontory at the superior aspect of S1 in 20 patients (27%). The distance between the promontory and the next bony structure (L5) was 13 mm (25th-75th interquartile range, 11-16). In women without disc at the promontory, the median distance between the promontory and the base of L5 disc was 1.29 mm (interquartile range, 1.1-2.2). The mean height of the disc was 13.3 mm (4.4-20.6 mm). Age was not associated with the most prominent structure (P = 0.2), nor was it correlated to disc height (P = 0.27, r = 0.13) or distance to L5 (P = 0.75, r = 0.04).

CONCLUSIONS: Given the high proportion of women with an intervertebral disc at the promontory, suture placement strategies that avoid this location may avoid-reduce disc-related sequelae after sacrocolpopexy.