Visualisation of sacral nerve roots and sacral plexus on gynecological transvaginal ultrasound

To investigate the feasibility of identifying and measuring the normal sacral plexus (SP) and measuring their size on a gynecological transvaginal ultrasound (TVS) examination. Prospective single, tertiary gynecological referral-centre observational study including consecutive women undergoing TVS performed for various indications from November 2021 to January 2022. A standardised assessment of the pelvic organs was performed, with the recording of any congenital or acquired uterine pathology and ovarian abnormalities. The visualisation of SPs on both sides was attempted in all cases. The success rate and the time needed for identifying in finding the SPs were recorded and measurements of the SP were made. 326 patients were included in the study. In all women the SP was successfully identified at least on one side. SPs were visualised bilaterally in 317 women (97.2% (95% CI, 94.4–98.5%)). Only the right SP was seen in 3/326 (0.9% (95% CI, 02–2.7%)), and only the left in 6/326 women (1.8% (95% CI, 0.6–4.0%)) (p = 0.5048). There were no significant differences in the median time required to visualise the right and the left SP: 9.0 s (IQR, 8.0–10.0) and 9.0 s (IQR, 8.0–10.0), respectively (p = 0.0770). The median transverse diameter of the right SP was 15.0 mm (IQR, 14.2–15.6). The median diameter of the left SP was 14.9 mm (IQR, 14.4-15.6). We described a novel method, for the consistent and fast identification of the SP during TVS. The integration of the assessment of the SP into routine pelvic TVS may be particularly helpful for women suffering from deep endometriosis.