A New Approach to Monitor Spinal Cord Vitality in Real Time
Spinal cord monitoring during various pathophysiological situations such as: spinal cord injury, spinal arterial sclerosis and different surgical procedures is essential to assure spinal cord integrity. Up to now, the most common methods in experimental and clinical practice includes the monitoring of Somatosensory Evoked Potential or Direct Motor Pathway Stimulation techniques.1 In the last decade a few publications described the use of laser Doppler flowmetry (LDF) technique for spinal cord blood flow evaluation in experimental animals and during clinical procedures.2–5 These studies showed that the LDF technique is a sensitive, stable non-invasive tool for on-line evaluation of spinal cord blood flow (SCBF) and is well correlated with other quantitative blood flow approaches such as the microsphere method6 and the hydrogen clearance method.2 Under normal conditions, oxygen metabolism in the spinal cord is of 1–2 ml/100g/min while, the cerebral oxygen metabolism is 3.5m1/100g/min 7. Spinal cord oxygen metabolism decreases at the caudal direction, thus the medulla oblongata and the spinal cord are more resistant to oxygen deficiency than the cortex.8;7 NADH, a major component of the respiratory chain, is one of the most sensitive component to detect oxygen deficiency.9 A decrease in oxygen supply to the spinal cord tissue is followed by a decrease in ATP levels, a decrease in Na+/K+ ATPase activity and an increase in K+ extracellular levels.10 The monitoring of mitochondrial NADH in the spinal cord is rare in experimental animals and probably absent in clinical monitoring or studies. As earlier indicated, monitoring of the hemodynamic and metabolic state of the spinal cord is of a great importance in different pathophysiological situations, such as in the case of spinal cord injury.
KeywordsSpinal Cord Spinal Cord Injury Spinal Cord Tissue Laser Doppler Flowmeter Mitochondrial NADH
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