Neural entrapment during uterosacral ligament suspension: an anatomic study of female cadavers.

OBJECTIVE: To describe retroperitoneal neural structures at risk during uterosacral ligament suspension and to estimate risk of neural injury based on uterosacral ligament suspension suture placement technique.
METHODS: Uterosacral ligament suspension was performed in 10 unembalmed female cadavers. In each cadaver, bilateral uterosacral ligament suspension sutures were placed using different techniques, as described in the literature. Distances from the ischial spine and instances of neural entrapment were recorded. Biopsy specimens of the deepest (most dorsal) tissue that each suture traversed were immunostained with a nerve-specific (S100) antibody, and the largest nerve diameter was recorded.
RESULTS: Median location of sutures relative to the ischial spine did not differ significantly by suture technique. Portions of sacral nerve roots were encircled by uterosacral ligament suspension sutures in seven cadavers. There were no instances of nerve entrapment when sutures were placed while tenting the ligament with an Allis clamp, although these sutures contained a less substantial purchase of connective tissue. In six cadavers, sacral nerves were encircled by sutures placed using a dorsal and posterior arc, regardless of the needle size. In one instance, only the larger CT-1 needle encircled sacral nerve roots. S100 immunostaining confirmed gross findings, with nerve tissue in all specimens (diameter 30-1,225 micrometers). Mean nerve diameter was significantly larger in biopsy specimens in which entrapment was noted grossly (472 micrometers compared with 108 micrometers; P<.001).
CONCLUSION: Sacral nerve roots are the most vulnerable neural structures during uterosacral ligament suspension. Suture placement directly into the uterosacral ligament with a dorsal and posterior needle arc results in a higher risk of nerve entrapment compared with ventral tenting of the ligament.