Continuous Monitoring of Cerebrospinal Fluid Oxygen Tension in Relation to Motor Evoked Potentials during Spinal Cord Ischemia in Pigs

2005 ◽  
Vol 102 (2) ◽  
pp. 340-345 ◽  
Author(s):  
Jeroen Lips ◽  
Peter de Haan ◽  
Gert Joan Bouma ◽  
Rebecca Holman ◽  
Eric van Dongen ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Cerebrospinal Fluid ◽  
Evoked Potentials ◽  
Continuous Monitoring ◽  
Motor Evoked Potentials ◽  
Spinal Cord Ischemia ◽  
Predictive Values ◽  
Diagnostic Characteristics ◽  
Segmental Arteries ◽  
Po2 Measurement

Background Perioperative assessment of spinal cord oxygenation might guide measures to prevent neurologic deficits secondary to ischemic or traumatic damage of the spinal cord. Although cerebrospinal fluid (CSF) partial pressure of oxygen (Po2) measurement has been used to detect spinal cord ischemia (SCI), the diagnostic value and the temporal resolution of CSF Po2 measurement compared with functional assessment of the spinal cord is unknown. This study compared CSF Po2 with transcranial motor evoked potentials (tcMEPs) for detection of experimental SCI. Methods The aorta and segmental arteries were exposed in 10 sufentanil-ketamine-anesthetized pigs (weight, 40-50 kg). Myogenic tcMEPs were recorded from the upper and lower limbs, and continuous assessment of CSF Po2 was provided by two Clark-type microcatheters inserted in the lumbar and thoracic intrathecal space. Graded lumbar SCI was produced by sequential clamping of segmental arteries. The relation between CSF Po2 and tcMEP during graded SCI was determined using linear regression. Diagnostic characteristics of CSF Po2 values for clinical SCI were determined using different cutoff points of CSF Po2. Results Lumbar CSF Po2 (baseline, 44 [interquartile range, 38-54] mmHg) decreased below 50% in all animals and was linearly related to loss of tcMEP amplitude in all animals. The median lumbar CSF Po2 during reduction of tcMEP to less than 25% of baseline was 11 (4-29) mmHg, whereas thoracic CSF Po2 remained constant (40 [28-50] mmHg). During absence of the tcMEP signal, lumbar CSF Po2 was less than 20 mmHg in 80% of the animals. Optimal sensitivity and predictive values of CSF Po2 measurement for SCI were in the range of 40-60% of baseline. Conclusions The data indicate that intrathecal Po2 measurement is a sensitive monitoring technique to track real-time changes in local spinal cord oxygenation. Continuous monitoring of CSF Po2 might be applied for evaluation of patients who are at risk for direct or secondary SCI.

scholarly journals Transesophageal versus transcranial motor evoked potentials to monitor spinal cord ischemia

2016 ◽  
Vol 151 (2) ◽  
pp. 509-517 ◽  
Author(s):  
Kazumasa Tsuda ◽  
Norihiko Shiiya ◽  
Daisuke Takahashi ◽  
Kazuhiro Ohkura ◽  
Katsushi Yamashita ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Motor Evoked Potentials ◽  
Spinal Cord Ischemia ◽  
Transcranial Motor Evoked Potentials

The Role of Transcranial Motor Evoked Potentials in Predicting Neurologic and Histopathologic Outcome after Experimental Spinal Cord Ischemia

2002 ◽  
Vol 97 (1) ◽  
pp. 183-191 ◽  
Author(s):  
Jeroen Lips ◽  
Peter de Haan ◽  
Steven W. de Jager ◽  
Ivo Vanicky ◽  
Michael J. Jacobs ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Motor Function ◽  
Motor Evoked Potentials ◽  
Spinal Cord Ischemia ◽  
Neurologic Outcome ◽  
Neurologic Dysfunction ◽  
Reduction Group ◽  
Group A ◽  
Group B

Background Monitoring of myogenic motor evoked potentials to transcranial stimulation (tcMEPs) is clinically used to assess motor pathway function during aortic and spinal procedures that carry a risk of spinal cord ischemia (SCI). Although tcMEPs presumably detect SCI before irreversible neuronal deficit occurs, and prolonged reduction of tcMEP signals is thought to be associated with impending spinal cord damage, experimental evidence to support this concept has not been provided. In this study, histopathologic and neurologic outcome was examined in a porcine model of SCI after different durations of intraoperative loss of tcMEP signals. Methods In 15 ketamine-sufentanil-anesthetized pigs (weight, 35-45 kg) the spinal cord feeding lumbar arteries were exposed. tcMEP were recorded from the upper and lower limbs. Under normothermic conditions, animals were randomly allocated to undergo short-term tcMEP reduction (group A, < 10 min, n = 5) or prolonged tcMEP reduction (group B, 60 min, n = 10), resulting from temporary or permanent clamping of lumbar segmental arteries. Neurologic function was evaluated every 24 h, and infarction volume and the number of eosinophilic neurons and viable motoneurons in the lumbosacral spinal cord was evaluated 72 h after induction of SCI. Results In all animals except one, segmental artery clamping reduced tcMEP to below 25% of baseline. All but one animal in group A had reduced tcMEP for less than 10 min and had normal motor function and no infarction at 72 h after the initial tcMEP reduction. Seven animals in group B (70%) had reduced tcMEP signals for more than 60 min and were paraplegic with massive spinal cord infarction at 72 h. Two animals (one in both groups) had tcMEP loss for 40 min, with moderate infarction and normal function. In general, histopathologic damage and neurologic dysfunction did not occur when tcMEP amplitude recovered within 10 and 40 min after the initial decline, respectively. Conclusion Prolonged reduction of intraoperative tcMEP amplitude is predictive for postoperative neurologic dysfunction, while recovery of the tcMEP signal within 10 min after the initial decline corresponds with normal histopathology and motor function in this experimental model. This finding confirms that intraoperative tcMEPs have a good prognostic value for neurologic outcome during procedures in which the spinal cord is at risk for ischemia.

scholarly journals Spinal Cord Parenchyma Vascular Redistribution Underlies Hemodynamic and Neurophysiological Changes at Dynamic Neck Positions in Cervical Spondylotic Myelopathy

2021 ◽  
Vol 15 ◽  
Author(s):  
Zhengran Yu ◽  
Xing Cheng ◽  
Jiacheng Chen ◽  
Zhong Huang ◽  
Shaofu He ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Cervical Spondylotic Myelopathy ◽  
Motor Evoked Potentials ◽  
Dynamic Compression ◽  
Dynamic Change ◽  
Spinal Cord Ischemia ◽  
Cervical Cord ◽  
Similar Degree ◽  
Neck Flexion

Cervical spondylotic myelopathy (CSM) is a degenerative condition of the spine that caused by static and dynamic compression of the spinal cord. However, the mechanisms of motor and somatosensory conduction, as well as pathophysiological changes at dynamic neck positions remain unclear. This study aims to investigate the interplay between neurophysiological and hemodynamic responses at dynamic neck positions in the CSM condition, and the pathological basis behind. We first demonstrated that CSM patients had more severe dynamic motor evoked potentials (DMEPs) deteriorations upon neck flexion than upon extension, while their dynamic somatosensory evoked potentials (DSSEPs) deteriorated to a similar degree upon extension and flexion. We therefore generated a CSM rat model which developed similar neurophysiological characteristics within a 4-week compression period. At 4 weeks-post-injury, these rats presented decreased spinal cord blood flow (SCBF) and oxygen saturation (SO2) at the compression site, especially upon cervical flexion. The dynamic change of DMEPs was significantly correlated with the change in SCBF from neutral to flexion, suggesting they were more sensitive to ischemia compared to DSSEPs. We further demonstrated significant vascular redistribution in the spinal cord parenchyma, caused by angiogenesis mainly concentrated in the anterior part of the compressed site. In addition, the comparative ratio of vascular densities at the anterior and posterior parts of the cord was significantly correlated with the perfusion decrease at neck flexion. This exploratory study revealed that the motor and somatosensory conductive functions of the cervical cord changed differently at dynamic neck positions in CSM conditions. Compared with somatosensory conduction, the motor conductive function of the cervical cord suffered more severe deteriorations upon cervical flexion, which could partly be attributed to its higher susceptibility to spinal cord ischemia. The uneven angiogenesis and vascular distribution in the spinal cord parenchyma might underlie the transient ischemia of the cord at flexion.

scholarly journals Motor and Somatosensory Evoked Potentials

2008 ◽  
Vol 108 (4) ◽  
pp. 580-587 ◽  
Author(s):  
Timothy S.J. Shine ◽  
Barry A. Harrison ◽  
Martin L. De Ruyter ◽  
Julia E. Crook ◽  
Michael Heckman ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Aortic Aneurysm ◽  
Evoked Potentials ◽  
Somatosensory Evoked Potentials ◽  
Motor Evoked Potentials ◽  
Spinal Cord Ischemia ◽  
Thoracoabdominal Aortic Aneurysm ◽  
Aortic Aneurysms ◽  
Aortic Cross Clamp ◽  
Surgical Interventions

Background Paraplegia is a devastating complication for patients undergoing repair of thoracoabdominal aortic aneurysms. A monitor to detect spinal cord ischemia is necessary if anesthesiologists are to intervene to protect the spinal cord during aortic aneurysm clamping. Methods The medical records of 60 patients who underwent thoracoabdominal aortic aneurysm repair with regional lumbar epidural cooling with evoked potential monitoring were reviewed. The authors analyzed latency and amplitude of motor evoked potentials, somatosensory evoked potentials, and H reflexes before cooling and clamping, after cooling and before clamping, during clamping, and after release of aortic cross clamp. Results Twenty minutes after the aortic cross clamp was placed, motor evoked potentials had 88% sensitivity and 65% specificity in predicting spinal cord ischemia. The negative predictive value of motor evoked potentials at 20 min after aortic cross clamping was 96%. Conclusions Rapid loss of motor evoked potentials or H reflexes after application of the aortic cross clamp identifies a subgroup of patients who are at high risk of developing spinal cord ischemia and in whom aggressive anesthetic and surgical interventions may be justified.

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