HYPERBARIC OXYGEN IMPROVES PERIPHERAL NERVE REGENERATION
Several studies have documented the effectiveness of hyperbaric oxygen in
models of acute and delayed crush injury. Intermittent exposure to
hyperbaric hyperoxia serves to interrupt the injury cycle of edema, ischemia
and tissue necrosis(1), as well as hemorrhagic hypotension(2), which in turn
leads to former edema and ischemia. Tissue ischemia is countered by the
ability of hyperbaric doses of oxygen to elevate tissue oxygen tensions(3).
Furthermore, edema is reduced, secondary to hyperoxia-induced arteriolar
vasoconstriction(4), leading to improved tissue viability, thereby reducing
necrosis(1). Hyperbaric oxygen has also been studied in models of peripheral
nerve injury(5).
Researchers from the US Air Force School Aerospace Medicine and Louisiana
State University recently sought to determine what, if any, morphologic
changes are associated with hyperbaric oxygen treated peripheral nerve
injury(6). Their model involved a crushed sciatic nerve in the rabbit.
Exposure to hyperbaric oxygen across the range of current clinical dose
schedules was compared to untreated, and pressure (hyperbaric air) controls.
The extent of nerve regeneration was documented via morphologic analysis of
electron micrographs, by a pathologist blinded as to group.
All of the animals exposed to hyperbaric doses of oxygen were reported to
demonstrate advanced stages of a healed nerve, in contrast to both control
groups.
As this research was limited to a determination of regeneration of
morphology, the exact effects of hyperbaric oxygen were not known. The
authors speculate, however, that there may be several suggesting increased
myelination, decreased edema, reduced internal collagen and improvements in
neurofilamentous material density. They conclude that this study provides
additional evidence of a link between tissue oxygen levels and the health of
peripheral nerves.
... all animals exposed to hyperbaric oxygen "demonstrated characteristics
expected of in the advanced stages of a healed nerve"
References
- Strauss MB et al.: Delayed use of hyperbaric oxygen for treatment of a model anterior compartment syndrome. Journal of Orthopedic Research 1986;
- 4:108-111.
- Skyhar MJ et al.: Hyperbaric oxygen reduces edema and necrosis of skeletal muscle in compartment syndromes associated with hemorrhagic hypotension. Journal of Bone and Joint Surgery 1986;68A:1218-1224
- Nylander G: Tissue ischemia and hyperbaric oxygen treatment. Scand 1986; suppl. 533.
- Nylander G et al.: Reduction of postischemic edema with hyperbaric oxygen. Plastic and Reconstructive Surgery 1985;76:595-603
- Zamboni WA et al.: Functional evaluation of peripheral-nerve repair and the effect of hyperbaric oxygen. Journal of Reconstructive Microsurgery 1995; 11:27-29.
- Bradshaw PO, et al.: Effect of hyperbaric oxygenation on peripheral nerve regeneration in adult male rabbits. Undersea and Hyperbaric Medicine 1996; 23(2): 107-113.
Reprinted with Permission
Brain Disorders/Neurological Index
