• Shigeru Kobayashi, Erisa Sabakaki Mwaka, Adam Meir, Kenzo Uchida, Kenichi Takeno, Tsuyoshi Miyazaki, Masafumi Kubota, Hideaki Nakajima, Eiki Nomura, Hidezo Yoshizawa, and Hisatoshi Baba.
• Department of Orthopaedics and Rehabilitation Medicine, Faculty of Medical Sciences, The University of Fukui, Matsuoka, Fukui, Japan. kshigeru@u-fukui.ac.jp
• Spine. 2009 May 1; 34 (10): 990-7.

Study DesignThis study is to investigate the changes of vasomotion of intraradicular microvessels in vivo.ObjectiveWe have observed microvascular corrosion casts of the lumbar nerve root by scanning electron microscopy and used an immunohistochemical technique to investigate the presence and distribution of autonomic and sensory nerve in blood vessels of the nerve root.Summary Of Background DataIt is generally considered that the genesis of radiculopathy associated with the degenerative conditions of the spine may result from both mechanical compression and circulatory disturbance. However, the neurogenic control of intraradicular blood flow has received little attention in the past.MethodsFor three-dimensional observation of intraradicular vessels, we used scanning electron microscopic examination of microvascular corrosion casts in ten Wister rats. To investigate the mechanism of vasomotion of the nerve root, we used immunohistochemical methods. The sections were incubated overnight with antisera to tyrosine hydroxylase, choline acetyl transferase, substance P, calcitonin-gene-related peptide, vasoactive intestinal peptide, somatostatin, neuropeptide Y, leucine-enkephalin, cholecystokinin octapeptide, brain-nitric oxide synthase, and endothelium-nitric oxide synthase. Abidin-biotin complex method was used as the immunohistochemical procedure and the sections were observed under the light microscope.ResultsThe general view of whole vascular casts of the lumbar spinal cord and nerve roots showed a high density of vessels. Bifurcation or anastomoses of capillaries approximately took place at right angles in a T-shaped pattern and capillaries showed a lot of ring-like compressions. This ring-like compression on the cast may represent a vascular sphincter in the microvessels. This study also reveals the existence of perivascular adrenergic, cholinergic, peptidergic, and nitroxydergic innervation with a possible role in neurogenic regulation of nerve root circulation.ConclusionPerivascular nerve plexuses around intraradicular microvessels suggest that the autonomic nerves play an important role in intraradicular circulation.

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