The nerve: A fragile balance between physiology and pathophysiology.
Regarding nerves as simple cables and electrical conduits is a gross error that does not allow us to understand the anomalies and disorders observed postoperatively. Instead, nerves should be seen as a living tissue of which physiological regulation is as complex as that of the blood-brain barrier. This review describes the basic structure and functions of this blood-nerve barrier and highlights the mechanisms of its breakdown and the resultant disorders. For clinical practice, it is important to note that the diffusion of molecules from the perineurium or from the blood is very limited, and so the blood-nerve barrier is a major pharmacologic barrier. Any stress upon neural physiological balance, particularly the terminal vascular blood supply, will induce the classic inflammatory cascade. Due to the complexity of the vascular system, nerve ischaemia will occur more quickly when the terminal blood supply is compromised. This blood supply can adapt in a variety of ways but when these possibilities of adaptation are exceeded, tissue ischaemia may be more extensive. Also, even after the initial injury has subsided, inflammation can cause a secondary insult. This could be particularly important in some patients with subclinical neuropathy.
From the Department of Anaesthesiology, Intensive Care, and Pain Medicine, University of Rennes, CHU of Rennes, Cedex 9, France (J-PE); Department of Anesthesiology, Perioperative Care, and Pain Medicine, NYU School of Medicine, New York, New York, USA (AA).
Jean-Pierre
JP
Estebe
Arthur
A
Atchabahian
D000818:Animals; D001812:Blood-Brain Barrier / Q000000981:diagnostic imaging / Q000502:physiology* / Q000503:physiopathology*; D006801:Humans; D007249:Inflammation / Q000000981:diagnostic imaging / Q000503:physiopathology; D059348:Peripheral Nerve Injuries / Q000000981:diagnostic imaging / Q000503:physiopathology*; D010525:Peripheral Nerves / Q000000981:diagnostic imaging / Q000502:physiology* / Q000503:physiopathology*