Towards rapid intraoperative axial localization of spinal cord ischemia with epidural diffuse correlation monitoring

Spinal cord ischemia leads to iatrogenic injury in multiple surgical fields, and the ability to immediately identify onset and anatomic origin of ischemia is critical to its management. Current clinical monitoring, however, does not directly measure spinal cord blood flow, resulting in poor sensitivity/specificity, delayed alerts, and delayed intervention. We have developed an epidural device employing diffuse correlation spectroscopy (DCS) to monitor spinal cord ischemia continuously at multiple positions. We investigate the ability of this device to localize spinal cord ischemia in a porcine model and validate DCS versus Laser Doppler Flowmetry (LDF). Specifically, we demonstrate continuous (>0.1Hz) spatially resolved (3 locations) monitoring of spinal cord blood flow in a purely ischemic model with an epidural DCS probe. Changes in blood flow measured by DCS and LDF were highly correlated (r = 0.83). Spinal cord blood flow measured by DCS caudal to aortic occlusion decreased 62%. This monitor demonstrated a sensitivity of 0.87 and specificity of 0.91 for detection of a 25% decrease in flow. This technology may enable early identification and critically important localization of spinal cord ischemia.

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Spatially resolved optical monitoring of spinal cord blood flow with a minimally invasive, multi-level epidural probe

10.1101/2020.10.06.326900 ◽

2020 ◽

Author(s):

David R. Busch ◽

Wei Lin ◽

Chia Chieh Goh ◽

Feng Gao ◽

Nicholas Larson ◽

...

Keyword(s):

Spinal Cord ◽

Blood Flow ◽

Cord Blood ◽

Spinal Cord Ischemia ◽

Correlation Spectroscopy ◽

Spinal Cord Blood Flow ◽

Doppler Flowmetry ◽

Spatially Resolved ◽

Highly Correlated ◽

Sensitivity Specificity

AbstractSpinal cord ischemia leads to iatrogenic injury in multiple surgical fields, and the ability to immediately identify onset and anatomic origin of ischemia is critical to its management. Current clinical monitoring, however, does not directly measure spinal cord blood flow, resulting in poor sensitivity/specificity, delayed alerts, and delayed intervention. We have developed an epidural device employing diffuse correlation spectroscopy (DCS) to monitor spinal cord ischemia continuously at multiple positions. We investigate the ability of this device to localize spinal cord ischemia in a porcine model and validate DCS versus Laser Doppler Flowmetry (LDF).Specifically, we demonstrate continuous (>0.1Hz) spatially resolved (3 locations) monitoring of spinal cord blood flow in a purely ischemic model with an epidural DCS probe. Changes in blood flow measured by DCS and LDF were highly correlated (r=0.83). Spinal cord blood flow measured by DCS caudal to aortic occlusion decreased 62%, with a sensitivity of 0.87 and specificity of 0.91 for detection of a 25% decrease in flow. This technology may enable early identification and critically important localization of spinal cord ischemia.

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EFFECT OF ISCHEMIC PRECONDITIONING ON SPINAL CORD BLOOD FLOW IN A RAT MODEL OF SPINAL CORD ISCHEMIA WHEN MEASURED BY LASER DOPPLER FLOWMETRY

Anesthesia & Analgesia ◽

10.1097/00000539-199904001-00011 ◽

1999 ◽

Vol 88 (Supplement) ◽

pp. 11SCA

Author(s):

DD Deal ◽

&NA; Colonna ◽

DA Zvara ◽

JC Vernon ◽

M Gowda

Keyword(s):

Spinal Cord ◽

Blood Flow ◽

Cord Blood ◽

Laser Doppler Flowmetry ◽

Ischemic Preconditioning ◽

Rat Model ◽

Spinal Cord Ischemia ◽

Laser Doppler ◽

Spinal Cord Blood Flow ◽

Doppler Flowmetry

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Fiber-optic Monitoring of Spinal Cord Hemodynamics in Experimental Aortic Occlusion

Anesthesiology ◽

10.1097/aln.0000000000000883 ◽

2015 ◽

Vol 123 (6) ◽

pp. 1362-1373 ◽

Cited By ~ 9

Author(s):

Angela S. Kogler ◽

Thomas V. Bilfinger ◽

Robert M. Galler ◽

Rickson C. Mesquita ◽

Michael Cutrone ◽

...

Keyword(s):

Spinal Cord ◽

Blood Flow ◽

Cord Blood ◽

Fiber Optic ◽

Spinal Cord Ischemia ◽

Correlation Spectroscopy ◽

Aortic Occlusion ◽

Spinal Cord Blood Flow ◽

Flow Measurements ◽

Blood Flow Measurements

Abstract Background Spinal cord ischemia occurs frequently during thoracic aneurysm repair. Current methods based on electrophysiology techniques to detect ischemia are indirect, non-specific, and temporally slow. In this article, the authors report the testing of a spinal cord blood flow and oxygenation monitor, based on diffuse correlation and optical spectroscopies, during aortic occlusion in a sheep model. Methods Testing was carried out in 16 Dorset sheep. Sensitivity in detecting spinal cord blood flow and oxygenation changes during aortic occlusion, pharmacologically induced hypotension and hypertension, and physiologically induced hypoxia/hypercarbia was assessed. Accuracy of the diffuse correlation spectroscopy measurements was determined via comparison with microsphere blood flow measurements. Precision was assessed through repeated measurements in response to pharmacologic interventions. Results The fiber-optic probe can be placed percutaneously and is capable of continuously measuring spinal cord blood flow and oxygenation preoperatively, intraoperatively, and postoperatively. The device is sensitive to spinal cord blood flow and oxygenation changes associated with aortic occlusion, immediately detecting a decrease in blood flow (−65 ± 32%; n = 32) and blood oxygenation (−17 ± 13%, n = 11) in 100% of trials. Comparison of spinal cord blood flow measurements by the device with microsphere measurements led to a correlation of R2 = 0.49, P < 0.01, and the within-sheep coefficient of variation was 9.69%. Finally, diffuse correlation spectroscopy is temporally more sensitive to ischemic interventions than motor-evoked potentials. Conclusion The first-generation spinal fiber-optic monitoring device offers a novel and potentially important step forward in the monitoring of spinal cord ischemia.

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Spinal Cord Blood Flow after Ischemic Preconditioning in a Rat Model of Spinal Cord Ischemia

The Scientific World JOURNAL ◽

10.1100/tsw.2004.186 ◽

2004 ◽

Vol 4 ◽

pp. 892-898 ◽

Cited By ~ 3

Author(s):

David Zvara ◽

James M. Zboyovski ◽

Dwight D. Deal ◽

Jason C. Vernon ◽

David M. Colonna

Keyword(s):

Spinal Cord ◽

Blood Flow ◽

Cord Blood ◽

Ischemic Preconditioning ◽

Spinal Cord Ischemia ◽

Flow Analysis ◽

Lumbar Spinal Cord ◽

Sprague Dawley ◽

Spinal Cord Blood Flow ◽

Significant Difference

Spinal cord blood flow after ischemic preconditioning is poorly characterized. This study is designed to evaluate spinal cord blood flow patterns in animals after acute ischemic preconditioning. Experiment 1: After a laminectomy and placement of a laser Doppler probe over the lumbar spinal cord to measure spinal cord blood flow, 16 male Sprague-Dawley rats were randomized into two groups: ischemic preconditioning (IPC, n = 8), and control (CTRL, n = 8). Rats in the CTRL and the IPC groups were subjected to 12 min of ischemia directly followed by 60 min of reperfusion. IPC rats received 3 min of IPC and 30 min of reperfusion prior to the 12-min insult period. Experiment 2: After instrumentation, the rats were randomized into three groups: control (CTRL, n = 7), ischemic preconditioning (IPC, n = 7), and time control (TC, n = 4). Rats in the CTRL and the IPC groups were subjected to the same ischemia and reperfusion protocol as above. The TC group was anesthetized for the same time period as the CTRL and the IPC groups, but had no ischemic intervention. Microspheres were injected at baseline and at 15 and 60 min into the final reperfusion. All rats were euthanized and tissue harvested for spinal cord blood flow analysis. In Experiment 1, there was a slight, significant difference in spinal cord blood flow during the ischemic period; however, this difference soon disappeared during reperfusion. In experiment 2, there was no difference in blood flow at any experimental time. The results of these experiments demonstrate that IPC slightly enhances blood flow to the spinal cord during ischemia; however, this effect is not sustained during the reperfusion period.

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Validation of laser-Doppler flowmetry in measurement of spinal cord blood flow

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1989.257.2.h674 ◽

1989 ◽

Vol 257 (2) ◽

pp. H674-H680 ◽

Cited By ~ 2

Author(s):

P. J. Lindsberg ◽

J. T. O'Neill ◽

I. A. Paakkari ◽

J. M. Hallenbeck ◽

G. Feuerstein

Keyword(s):

Spinal Cord ◽

Blood Flow ◽

Cord Blood ◽

Laser Doppler Flowmetry ◽

Laser Doppler ◽

Microvascular Blood Flow ◽

Base Line ◽

Spinal Cord Blood Flow ◽

Flow Measurements ◽

Doppler Flowmetry

Laser-Doppler flowmetry (LDF) is a non-invasive method for continuous on-line monitoring of microvascular blood flow. LDF has previously been validated with established methods in various tissues, yet its validity and resolution in the central nervous system (CNS) remain unclear. We compared LDF with the microsphere method (MS) using two independent laser probes placed on the dorsal lumbar spinal cord (L5 laminectomy) of anesthetized rabbits (n = 9). After base-line flow measurements, spinal cord blood flow (SCBF) was increased (up to 50%) with phenylephrine (10-80 micrograms.kg-1.min-1 iv) and decreased (up to 50%) with chlorisondamine (10 mg/kg iv) or other stimuli. The percentage changes of lumbar SCBF and vascular resistance (VR) from the base line obtained by LDF and MS excellently agreed (rBF = 0.86, rVR = 0.94, P less than 0.0001). LDF estimated also the absolute SCBF values parallel to MS (r = 0.77, P less than 0.001). In conclusion, the validity of LDF in estimating the SCBF and dynamic changes of BF and VR is confirmed. Therefore, LDF may prove useful for monitoring CNS microcirculation in normal or pathophysiological states.

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Interleukin-1 beta enhances spinal cord blood flow after intrathecal administration in the normal rat

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1995.269.5.r1032 ◽

1995 ◽

Vol 269 (5) ◽

pp. R1032-R1037 ◽

Cited By ~ 1

Author(s):

C. R. Plata-Salaman ◽

G. Kelly ◽

C. Agresta ◽

K. Taylor ◽

S. K. Salzman

Keyword(s):

Spinal Cord ◽

Blood Flow ◽

Cord Blood ◽

Interleukin 1 ◽

Specific Interaction ◽

Receptor Site ◽

Intrathecal Administration ◽

Interleukin 1 Beta ◽

Spinal Cord Blood Flow ◽

Doppler Flowmetry

The effects of acute intrathecal recombinant human interleukin-1 beta (rhIL-1 beta) administration on spinal cord blood flow (SCBF), volume, and velocity were determined by laser-Doppler flowmetry in normal anesthetized rats with the use of a randomized and blinded protocol. The intrathecal administration of rhIL-1 beta (0.16-16 ng) produced a dose-dependent increase in SCBF that was not related to changes in blood pressure; arterial pH, PO2, PCO2; or spinal cord temperature. The IL-1 beta-induced enhancement of SCBF was directly proportional to the resultant elevation of spinal cord rhIL-1 beta content and was significantly correlated with an elevated blood velocity. The IL-1 receptor antagonist (IL-1ra) in concentrations 50- and 200-fold higher than IL-1 beta completely blocked the IL-1 beta-induced increase in SCBF when both compounds were administered concomitantly, but when administered alone, IL-1ra did not affect SCBF or other parameters. This suggests that IL-1 beta action was mediated by a specific interaction with an IL-1 membrane receptor site. The results suggest a role of IL-1 beta in the regulation of spinal cord hemodynamics. A potential pharmacological approach using IL-1 agonists for the treatment of the delayed appearance of posttraumatic spinal ischemia is proposed.

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