The Transdural Course of Radicular Spinal Cord Veins--A Microangiographical and Microscopical Study

Area of Science:

• Neuroanatomy
• Vascular Anatomy
• Spinal Cord Circulation

Background:

• The venous drainage system of the spinal cord, particularly the transdural course of radiculomedullary veins, is complex.
• Understanding the morphology and function of these vessels is crucial for comprehending spinal cord blood circulation and potential pathologies like arteriovenous shunts.

Purpose of the Study:

• To investigate the morphological characteristics of radiculomedullary veins at their transdural passage.
• To determine the connection between these transdural segments and the internal vertebral venous plexus.
• To evaluate the efficacy of a reflux-impeding mechanism at the transdural segment.

Main Methods:

• Microscopic examination of 102 radiculospinal veins using serial paraffin and semi-thin sections.
• Microangiographic study of 26 vessels with barium sulphate opacification (orthograde and retrograde).
• Contact microradiography of paraplast-embedded specimens using high-resolution spectroscopic plates.

Main Results:

• Transdural veins exhibited lumen narrowing, altered vessel wall composition, and tortuosity.
• Two main types of transdural arrangements were identified: slit type (60%) and bulge/nodular type (35%).
• Reflux from the epidural to radicular veins was inducible in a small percentage of specimens (2/14); the epidural plexus often consisted of lacunar spaces.

Conclusions:

• Reflux control at the dural level is not consistently effective and may be physiological.
• The identified arrangements of the transdural course likely modulate venous flow, though the specific purpose of the two types remains unclear.
• The clinical impact of impaired reflux control is uncertain, contrasting with the severity of dural arteriovenous shunts; the role of the epidural venous plexus in spinal cord circulation needs further elucidation.