Prenatal Assessment of the Position of Fetal Conus Medullaris as a Predictor of Fetal Spinal Lesions

Zhao, Di; Wei, Qiuju; Cai, Ailong; Xie, Liangdi; Wang, Bing; Wang, Xiaoguang

doi:10.1002/jum.14326

Cited by 5 publications

(6 citation statements)

References 14 publications

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“…For example, Perlitz et al studied the CM position of 20 to 24 weeks’ GA fetuses on 2D ultrasonography by identifying the lowest rib and counting from T12; they found that in 93% of cases, CM was located at L2, L2–3, and L3 levels. Zhao et al and Lei et al used 3‐dimensional ultrasonography to demonstrate that the normal CM was at or above L3. These results indicated that the location of the CM position relative to S1 as a reference point was similar to that of other methods.…”

Section: Discussionmentioning

confidence: 99%

A method for quantitative 2‐dimensional sonographic analysis of the fetal conus medullaris position

Zhai

Cai

Wei

et al. 2018

J of Ultrasound Medicine

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Objective This study explored the use of 2‐dimensional (2D) ultrasound scans for the quantitative assessment of the fetal conus medullaris (CM) position and its correlation with gestational age (GA). Methods This was a prospective study. We identified the first sacral vertebra (S1) by intersection of 2 lines in 2D scans, then counted upward from S1 to determine the CM level and recorded the number of ossified sacral vertebral bodies. A quantitative assessment of the CM position was performed by measuring the distance between the CM and the midpoint of the S1 (CM–S1). The correlation between the CM‐S1 distance and GA was evaluated. Results We determined the CM level by identifying S1 first in 521 fetuses (GA, 20–38 weeks). The CM position in 70% of cases was at the L2 and L2–3 level, and at the L2 level or above after 37 weeks. The number of ossified sacral veterbral bodies was not consistent. CM–S1 measurements were easy to perform. A significant positive correlation between CM–S1 distance and GA was observed (R2 = .89, P < .05). The best‐fit formula was: CM–S1 distance = 1.57 × GA – 16.43. The normal reference range was established and the fifth percentile was calculated for each GA. Conclusions S1 was easily identified, and the CM position relative to S1 was useful. There was a substantial correlation between CM–S1 and GA. Below the fifth percentile it was suggested that tethered cord may exist.

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Section: Discussionmentioning

confidence: 99%

A method for quantitative 2‐dimensional sonographic analysis of the fetal conus medullaris position

Zhai

Cai

Wei

et al. 2018

J of Ultrasound Medicine

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“…Regarding morphology, the three studies 35 , 37 , 38 that addressed the distance between the CM and the end of the sacrum performed analyses according to gestational age group. In the studies that addressed the CM-S distance, only one 10 distributed the sample by gestational age group, while the other articles 9 , 36 , 39 , did not describe any division of the samples considering foetal age.…”

Section: Discussionmentioning

confidence: 99%

“…To identify S1, the studies evaluated lumbosacral curvature using ultrasound. This approach was performed with the use of two tangents drawn at the last lumbar and sacral ossification nuclei from bottom to top, the intersection of which was the CM 10 , 35 – 39 .…”

Section: Discussionmentioning

confidence: 99%

Ascent of the conus medullaris in human foetuses: a systematic review and meta-analysis

Almeida

Figueiredo

Zylberman

et al. 2022

Sci Rep

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The aim of the present systematic review and meta-analysis was to identify when the ascent of the conus medullaris occurs in human foetuses considering differences in evaluation methods and sample characteristics. Five databases were searched for relevant articles using different combinations of keywords. Article selection and data extraction were performed independently by two reviewers. Disagreements were resolved by a third reviewer. The variables were distributed into four groups according to the gestational age of the specimens: I (13–18 weeks); II (19–25 weeks); III (26–32 weeks); IV (33 weeks to the probable date of birth). Eighteen articles were included. The majority used imaging exams as the evaluation method. Cadaveric dissections were reported in the remaining articles. Only morphological studies were included in the meta-analysis. Significant ascent occurs between groups I and III as well as groups II and IV. Despite the considerable heterogeneity among the studies included in the present review, the findings enabled the determination that the conus medullaris reaches its normal birth level by the 26th week. Further analyses should be performed based on nationality and ethnicity to diminish the heterogeneity of the data.

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“…For example, Lu et al used angled lumbosacraljoint (a 15--20° angle between L5 and S1)asa reference to assess the relative relationship between the CM and the vertebra [8] . Hopmoann etaland Zhao et al measured the distance between the CM and the end of the sacral vertebrae (conus distance, CD) and found a linear correlation between CD and gestational week, biparietal diameter, abdominal circumference and femoral length [13,14] . However, the 2D ultrasound display is limited by the fact that the time of sacral vertebra ossi cation is correlated with gestational week.…”

Section: Discussionmentioning

confidence: 99%

“…With the advancement of 3D technology, the direct application of 3D reconstruction, together with using the T12 corresponding to the lowermost rib as reference, is becoming more authentic. Zhao et al compared 2D CD measurements with 3D imaging and found that 3D imaging is easierand more accurate when determining the location of foetal conus medullaris [14] . Moreover, and the application of high-frequency ultrasound showed the vertebral anatomy more clearly, giving it a signi cant advantage in the diagnosis of spinal dysraphisms.…”

Section: Discussionmentioning

confidence: 99%

Prenatal Assessment and pregnancy outcomes of foetal low-lying conus medullaris using 3D Ultrasound

Sun

Jing

Zhang

2022

Preprint

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Objectives This study aimed to follow up cases with low conus medullaris (CM) using three dimensional (3D) ultrasonography and analyze and explore the correlation between the CM location and the final prognosis. Methods 39 cases of low CM diagnosed prenatally in the Peking University First Hospital was collected retrospectively from January, 2019 to December, 2020. The location of CM was confirmed by 3D ultrasonography and clinical data including postnatal outcomes were collected.Results The average gestational weeks when low CM was diagnosed was between 23 and 24 weeks. Among 39 cases, there are 9 cases (23.1%) which were complicated with spine abnormality (3 cases of open spina bifida, 6 cases of tethered cord syndrome). Apart from 9 cases of pregnancy termination, the remaining 30 cases of live births had good prognosis, though 5 of 6 cases of tethered cord syndrome underwent the surgical release. The mean location of cases of open spinal dysraphism and cases of closed dysraphism/tethered cord syndrome was at L5 and between Lumber vertebra (L)5 and Sacral vertebra (S) 1 respectively, which showed statistically significance compared with the postnatally normal group. When we set Lumber 4.25 as the cut-off value to predict the diagnosis of spine abnormality (mainly open spina dysraphism and closed spinal dysraphism/tethered cord syndrome, the sensitivity was 66.7 and the specificity was 96% with the area under curve (AUC) at 0.877. Conclusion Low CM was related with spinal defects (mainly open spinal dysraphism and closed spinal dysraphism/tethered cord syndrome). Clinicians should be cautious especially when the location of CM was lower than L4. In cases of tethered cord syndrome, release surgery was needed according to the postnatal condition. Otherwise, the prognosis of low CM was good.

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Prenatal Assessment of the Position of Fetal Conus Medullaris as a Predictor of Fetal Spinal Lesions

Abstract: We propose the combined use of CM level location and CS distance measurement for the prenatal diagnosis of fetal spinal lesions for complementary needs.

Cited by 5 publications

References 14 publications

A method for quantitative 2‐dimensional sonographic analysis of the fetal conus medullaris position

A method for quantitative 2‐dimensional sonographic analysis of the fetal conus medullaris position

Ascent of the conus medullaris in human foetuses: a systematic review and meta-analysis

Prenatal Assessment and pregnancy outcomes of foetal low-lying conus medullaris using 3D Ultrasound

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