Cerebral abnormalities in lumbosacral neural tube closure defect: MR imaging evaluation.

OBJECTS

It was decided that patients with caudal neural tube closure defect should be evaluated by means of cranial MR scans, with special attention devoted to cerebral malformations other than craniospinal abnormalities.

METHODS

Twenty-four patients with lumbosacral neural tube closure defects, classified into myeloschisis (MS, 9 cases), meningo(myelo)cele (MMC, 10 cases) and spina bifida occulta with lumbosacral lipoma (LL, 5 cases), were evaluated in this way, and cerebral anomalies were found to be present in all MS patients, 8 with MMC and 2 with LL. The cerebral hemispheres were mildly to moderately hypoplastic in 6 patients, and hydrocephalus was present in 6 patients with MS and in 5 with MMC; LL was not associated with ventriculomegaly in any patient. Polymicrogyria was present in 6 patients with MS, in 3 with MMC, and in none of those with LL. Heterotopic gray matter was observed in only 2 patients with MS. Partial agenesis of the corpus callosum was found in 6 MS patients and in 6 patients with MMC, but was not seen in patients with LL. Cervicomedullary anomalies, such as herniation of the cerebellar tonsils through the foramen magnum, were found in 7 patients with MS, in 4 with MMC and in 2 with LL. While patients with LL were accompanied by only mild forebrain anomalies, cerebral abnormalities in MS and MMC were generally more severe in degree than those in LL. Among 21 patients in whom intellectual and performance status was evaluated, 9 of the 17 patients with cerebral anomalies had some degree of retardation, and the 4 without cerebral anomalies were normal.

CONCLUSIONS

Caudal neural tube closure defect is not a single developmental abnormality, and can be regarded as one part of the spectrum of malformations causing primary insults that are as yet unidentified to the developing central nervous system.