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Sacral agenesis and caudal spinal cord malformations
1Department of Neurosurgery, Children's Hospital of Pittsburgh, Pennsylvania.
Insights
Sacral agenesis (SA) in children often involves urinary and bowel dysfunction, with better preserved sensation than motor function. Neuroimaging reveals varied dural sac narrowing and conus medullaris abnormalities correlated with malformation severity.
Area of Science:
- Pediatric Neurology
- Developmental Biology
- Medical Imaging
Background:
- Sacral agenesis (SA) is a complex congenital anomaly affecting the lumbosacral spine.
- Associated conditions include OEIS complex and VATER syndrome, presenting with diverse malformations.
- Patients exhibit characteristic physical features and significant neurological deficits.
Purpose of the Study:
- To characterize the neuroimaging findings in sacral agenesis.
- To correlate imaging findings with clinical presentation and severity of malformations.
- To investigate the relationship between conus medullaris position and spinal abnormalities.
Main Methods:
- Retrospective study of 33 children and 1 adult with sacral agenesis.
- Utilized computed tomographic myelography and/or magnetic resonance imaging for detailed spinal assessment.
- Mean follow-up period of 4.7 years to monitor clinical progression.
Main Results:
- Lumbosacral sensation was better preserved than motor function; urinary and bowel symptoms were universal.
- Neuroimaging showed nonstenotic narrowing of the caudal bony canal and dural sac in most patients.
- Three patients (9%) had symptomatic dural stenosis. Conus medullaris position (above or below L1) correlated with sacral malformation severity.
Conclusions:
- Sacral agenesis presents with consistent neurological and physical findings, including sensory-motor deficits and bowel/bladder dysfunction.
- Neuroimaging is crucial for identifying structural abnormalities like dural narrowing and conus medullaris variations.
- The level and morphology of the conus medullaris are significant indicators of sacral malformation severity.
Abstract:
Thirty-three children and one adult with sacral agenesis (SA) were studied by computed tomographic myelography and/or magnetic resonance imaging and were monitored for a mean period of 4.7 years. Four children had the OEIS (concurrent omphalocele, cloacal exstrophy, imperforate anus, and spinal deformities) complex, and three others had VATER (vertebral abnormality, anal imperforation, tracheoesophageal fistula, and renal-radial anomalies) syndrome. All patients shared some of the characteristic features of SA, namely, a short, intergluteal cleft, flattened buttocks, narrow hips, distal leg atrophy, and talipes deformities. Neurologically, lumbosacral sensation was much better preserved than the motor functions, and urinary and bowel symptoms were universal. The level of the vertebral aplasia was correlated with the motor but not with the sensory level. The important neuroimaging findings of SA were as follows: 1) 12 patients (35%) had nonstenotic, tapered narrowing of the caudal bony canal, and 2 patients had hyperostosis indenting the caudal thecal sac; 2) 16 patients (47%) had nonstenotic, tapered narrowing and shortening of the dural sac, but 3 patients (9%) had true, symptomatic dural stenosis, in which the cauda equina was severely constricted by a pencil-sized caudal dural sac; 3) the coni could be divided into those ending above the L1 vertebral body (Group 1, 14 patients) and those ending below L1 (Group 2, 20 patients). Thirteen of 14 Group 1 coni were club or wedge-shaped, terminating abruptly at T11 or T12, as if the normal tip was missing. All 20 Group 2 coni were tethered: 13 were tethered by a thick filum; 2 were extremely elongated and had a terminal hydromyelia; 3 were terminal myelocystoceles; and 2 were tethered by a transitional lipoma. High blunt coni were highly correlated with high (severe) sacral malformations (sacrum ending at S1), but low-lying tethered coni were highly correlated with low sacral malformations (S2 or lower pieces present).(ABSTRACT TRUNCATED AT 400 WORDS)