Visualization of sacral nerve roots and sacral plexus on gynecological transvaginal ultrasound: feasibility study

Objective: To investigate the feasibility of identifying and measuring the normal sacral plexus (SP) on gynecological transvaginal ultrasound (TVS) examination.

Methods: This was a prospective observational study conducted at a single tertiary gynecological referral center, including consecutive women undergoing TVS for various indications between November 2021 and January 2022. A standardized assessment of the pelvic organs was performed and the presence of any congenital or acquired uterine pathology or ovarian abnormality was recorded. Visualization of the right and left SP was attempted in all cases. The success rate and the time needed to identify the SP were recorded and measurements of the SP were made.

Results: A total of 326 patients were included in the study. In all women, the SP was identified successfully on at least one side. SP were visualized bilaterally in 317 (97.2% (95% CI, 94.4-98.5%)) women. Only the right SP was seen in 3/326 (0.9% (95% CI, 0.2-2.7%)) and only the left in 6/326 (1.8% (95% CI, 0.6-4.0%)) (P = 0.5048). There was no significant difference in the median time required to visualize the right vs left SP (9.0 (interquartile range (IQR), 8.0-10.0) s vs 9.0 (IQR, 8.0-10.0) s; P = 0.0770). The median transverse diameter of the right SP was 15.0 (IQR, 14.2-15.6) mm and that of the left SP was 14.9 (IQR, 14.4-15.6) mm.

Conclusions: We describe a novel method which allows for the consistent and rapid identification of the SP on TVS. Integrating assessment of the SP into routine pelvic TVS may be helpful particularly for women suffering from deep endometriosis. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.