Microangiography of human fetal spinal cord

Development of the Arterial Supply of the Spinal Cord Tissue Based on Radioanatomical and Histological Studies in Cattle

PURPOSE

Angiographic techniques have gained increasing importance in suspected vascular disease of the spinal cord. This demands an advanced understanding of spinal cord blood vessel anatomy and its embryologically founded broad spectrum of variations. The aim of this study was to improve knowledge on contentious issues concerning the development of spinal cord arterial supply in higher mammals and to offer visual information of high didactic value.

METHODS

The prenatal development was examined in cattle, using multiplanar high-resolution microangiography of injected specimens and microscopic sections. The gestational ages of the 15 specimens were between the late embryonic and the early fetal period (5-11 weeks). Microangiography of the human spinal cord from an earlier published study were used to envisage an adult arterial vascularization pattern in higher mammals.

RESULTS

Establishment of the unpaired anterior spinal artery (ASA) goes through two procedures of reconfiguration until achieving its final design. Regression of the primarily established anteromedian tract is observed in cattle fetuses of 9-10 weeks. Return to the ontogenetic disposition of bilateral symmetry and a burst of vascularization from all parts of the spinal meninges follow and include the anterior median fissure as a preferred vascular pathway. Large sulcal/central arteries longitudinally anastomosing between each other emerge on both sides of the midline. The embryological pattern of exclusive peripheral medullary supply must have been converted into a combined system of predominant central (centrifugal) supply of the enlargements before a final unpaired ASA can be reconstructed.

CONCLUSION

Previous investigators focused on the early embryonic development of spinal cord arteries and missed the profound remodeling of the vascular architecture in the early fetal period.

Fetal akinesia deformation sequence with delayed skeletal muscle maturation and polymicrogyria: evidence for a hypoxic/ischemic pathogenesis

Multiple congenital contractures, also known as fetal akinesia deformation sequence (FADS) and related terms, result from decreased fetal movement. The underlying etiologies are diverse and include central nervous system (CNS) dysgeneses and primary myopathies. Persistent central nuclei or the presence of myotubes is often regarded as evidence of a primary myopathic etiology; however, these findings are also associated with impaired fetal innervation. We report 7 fetuses, estimated gestational age 20 to 23 weeks, with persistent myotubular morphology, a change that could be (mis)interpreted as a primary myopathy. In 4 of the patients, CNS histology showed hypoxic/ischemic injury, polymicrogyria, mineralized neurons, and microinfarcts with or without loss of anterior horn neurons. FADS cases with polymicrogyria have frequently been interpreted as a consequence of a primary brain malformation. Only a few descriptions of FADS associate polymicrogyria with CNS hypoxic/ischemic injury, however, and do not describe skeletal muscle maturation delay. We hypothesize that this combination of neural and muscular pathology is an under-recognized pattern in FADS, which results from diffuse hypoxic/ischemic injury involving the brain and spinal cord during early to middle gestation.

Origin of the anterior spinal artery

This investigation was designed to extend our present knowledge of the origin of the anterior spinal a. and is based on 80 brains of human cadavers. The anterior spinal a. is usually formed rostrally by the union of the anterior spinal branches from the intracranial segments of the vertebral aa. In this study, we observed three different locations of the origin of the anterior spinal a. Each type has different characteristics. A bilateral origin (type I) was present in 60 specimens (75%). This type could be further subdivided according to the caliber of the arteries, into the following subtypes: "balanced" (type Ia 42.5%), right-dominated (type Ib 17.5%), and left-dominated (type Ic 15%). A unilateral origin (type II) was found in 9 specimens (11.3%), and an origin in an intervertebral transverse anastomosis was demonstrated in 11 (13.8%). In all cases, the anterior spinal a. had an average caliber of 1.145 +/- 0.12 mm.

Angiography of the spinal cord. A review of contemporary techniques and applications

✓ The authors present a current review of the development, techniques, and applications of angiographic studies of the spinal cord, with special emphasis on selective arteriography.