Clinical value of prenatal ultrasound evaluation for fetal low-lying conus medullaris
10.3760/cma.j.cn113903-20250624-00323
- VernacularTitle:产前超声评估胎儿脊髓圆锥低位的临床价值
- Author:
Yunqi LI
1
;
Suzhen RAN
;
Peng TU
;
Bin ZHANG
Author Information
1. 重庆市妇幼保健院（重庆医科大学附属妇女儿童医院）超声科，重庆 401147
- Publication Type:Journal Article
- Keywords:
Prenatal ultrasound;
Low-lying conus medullaris;
Tethered cord
- From:
Chinese Journal of Perinatal Medicine
2025;28(11):969-973
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the clinical value of prenatal ultrasound in assessing fetal low-lying conus medullaris and prognostic factors.Methods:Prenatal ultrasound images and pregnancy outcomes were retrospectively analyzed for 54 pregnant women with fetal conus medullaris position below the third lumbar vertebra (L3) level detected by prenatal ultrasound at Chongqing Health Center for Women and Children from May 2017 to January 2024. Based on postnatal follow-up results (clinical symptoms, imaging data, or surgical findings within 5-year old), they were divided into normal (42 cases) and abnormal (12 cases) groups. Basic clinical data were collected, including initial conus medullaris position at first diagnosis (conus medullaris at L3 level defined as 3, between L3 and L4 as 3.5, and so on; at first sacral vertebra as 6, second sacral vertebra as 7), and changes in conus medullaris position during prenatal ultrasound or MRI follow-up. Independent sample t-tests and Chi square tests were used to compare changes in conus medullaris position, tethered cord phenomenon, and presence of spinal masses between groups. Results:The initial conus medullaris position in the abnormal group was significantly lower than in the normal group (4.7±1.5 vs. 3.7±0.4, t=－3.75, P<0.001), and the proportion of rising to L3 or above in utero was lower than in the normal group [2/9 vs. 78.1% (25/32), χ2=9.76, P=0.002]. The abnormal group had higher proportions of tethered cord phenomenon [5/12 vs. 0.0% (0/42), χ2=19.29, P<0.001] and spinal masses [9/12 vs. 2.4% (1/42), χ2=32.62, P<0.001] compared to the normal group. Among the abnormal group children, eight underwent postoperative surgery (three with tethered cord and meningocele, four with tethered cord and lipoma, one with tethered cord, meningocele, and lipoma), with an overall good postoperative prognosis. Conclusion:Prenatal ultrasound enables dynamic monitoring of fetal conus position, while characteristic findings (tethered cord signs and spinal masses) help identify potential tethered cord syndrome, providing crucial evidence for comprehensive prenatal evaluation and early intervention.
