A Study of Critical Events That Lead to Spinal Cord Injury and the Importance of Rapid Reversal of Surgical Steps in Improving Neurological Outcomes: A Porcine Model

Vishal Sarwahi, Jesse Galina, Sayyida Hasan, Beverly Ann Thornhill, Alan D. Legatt, Abhijit Pawar, Marina Moguilevich, Terry D. Amaral

Research output: Contribution to journalArticle

Abstract

Study Design. Porcine model. Objective. To quantify critical vascular and mechanical events that occur before and during an evolving spinal cord injury. Summary of Background Data. Spinal cord injuries are one of the most devastating complications in spine surgery. Intraoperative neuromonitoring changes can occur as a secondary event of spinal cord compression and decrease in spinal cord blood flow (SCBF). Laser Doppler flowmetry has been well validated for measuring blood flow. Methods. Seventeen pigs were studied, 14 of which completed the experiment. Multilevel, midthoracic laminectomies were performed. Laser Doppler flowmetry electrodes were placed on the dura to measure SCBF. Spinal cord injury was induced by incremental balloon inflation in the epidural space. The animals were separated into two groups. After motor-evoked potential (MEP) loss, group A underwent medical interventions and then balloon decompression approximately 20 minutes later. Group B underwent immediate balloon decompression followed by medical interventions. After interventions, wake-up test was performed and computed tomography scan measured thoracic spinal canal volume. Results. Median SCBF changes were seen 15.8 (5.4-25.1) minutes before MEP loss. However, the 20% threshold interval was often reached before. At the 20% threshold, median pressure was 7psi, balloon volume was 0.5cm3, and 50% of the spinal canal was compromised. In group A, no pigs moved and all had pathology indicating ischemia. In group B, 9 of 10 were found to be moving their hind legs with 7 indicating ischemia. Conclusion. Compression spinal cord injury is the end of a cascade involving increasing intracanal pressure, decreasing canal volume, and hypoperfusion. Rapid relief of compression leads to MEP return. SCBF monitoring can detect ischemia preinjury, giving surgeons an opportunity for early intervention.Level of Evidence: N/A.

Original languageEnglish (US)
JournalSpine
DOIs
StateAccepted/In press - Jan 1 2019

Fingerprint

Fetal Blood
Spinal Cord Injuries
Motor Evoked Potentials
Spinal Cord
Swine
Laser-Doppler Flowmetry
Spinal Canal
Ischemia
Decompression
Pressure
Epidural Space
Spinal Cord Compression
Laminectomy
Economic Inflation
Blood Vessels
Leg
Electrodes
Spine
Thorax
Tomography

Keywords

  • laminectomy
  • laser Doppler
  • motor-evoked potentials
  • neuromonitoring
  • spinal canal compromise
  • spinal cord blood flow
  • spinal cord injury

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Clinical Neurology

Cite this

A Study of Critical Events That Lead to Spinal Cord Injury and the Importance of Rapid Reversal of Surgical Steps in Improving Neurological Outcomes : A Porcine Model. / Sarwahi, Vishal; Galina, Jesse; Hasan, Sayyida; Thornhill, Beverly Ann; Legatt, Alan D.; Pawar, Abhijit; Moguilevich, Marina; Amaral, Terry D.

In: Spine, 01.01.2019.

Research output: Contribution to journalArticle

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abstract = "Study Design. Porcine model. Objective. To quantify critical vascular and mechanical events that occur before and during an evolving spinal cord injury. Summary of Background Data. Spinal cord injuries are one of the most devastating complications in spine surgery. Intraoperative neuromonitoring changes can occur as a secondary event of spinal cord compression and decrease in spinal cord blood flow (SCBF). Laser Doppler flowmetry has been well validated for measuring blood flow. Methods. Seventeen pigs were studied, 14 of which completed the experiment. Multilevel, midthoracic laminectomies were performed. Laser Doppler flowmetry electrodes were placed on the dura to measure SCBF. Spinal cord injury was induced by incremental balloon inflation in the epidural space. The animals were separated into two groups. After motor-evoked potential (MEP) loss, group A underwent medical interventions and then balloon decompression approximately 20 minutes later. Group B underwent immediate balloon decompression followed by medical interventions. After interventions, wake-up test was performed and computed tomography scan measured thoracic spinal canal volume. Results. Median SCBF changes were seen 15.8 (5.4-25.1) minutes before MEP loss. However, the 20{\%} threshold interval was often reached before. At the 20{\%} threshold, median pressure was 7psi, balloon volume was 0.5cm3, and 50{\%} of the spinal canal was compromised. In group A, no pigs moved and all had pathology indicating ischemia. In group B, 9 of 10 were found to be moving their hind legs with 7 indicating ischemia. Conclusion. Compression spinal cord injury is the end of a cascade involving increasing intracanal pressure, decreasing canal volume, and hypoperfusion. Rapid relief of compression leads to MEP return. SCBF monitoring can detect ischemia preinjury, giving surgeons an opportunity for early intervention.Level of Evidence: N/A.",
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AU - Galina, Jesse

AU - Hasan, Sayyida

AU - Thornhill, Beverly Ann

AU - Legatt, Alan D.

AU - Pawar, Abhijit

AU - Moguilevich, Marina

AU - Amaral, Terry D.

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N2 - Study Design. Porcine model. Objective. To quantify critical vascular and mechanical events that occur before and during an evolving spinal cord injury. Summary of Background Data. Spinal cord injuries are one of the most devastating complications in spine surgery. Intraoperative neuromonitoring changes can occur as a secondary event of spinal cord compression and decrease in spinal cord blood flow (SCBF). Laser Doppler flowmetry has been well validated for measuring blood flow. Methods. Seventeen pigs were studied, 14 of which completed the experiment. Multilevel, midthoracic laminectomies were performed. Laser Doppler flowmetry electrodes were placed on the dura to measure SCBF. Spinal cord injury was induced by incremental balloon inflation in the epidural space. The animals were separated into two groups. After motor-evoked potential (MEP) loss, group A underwent medical interventions and then balloon decompression approximately 20 minutes later. Group B underwent immediate balloon decompression followed by medical interventions. After interventions, wake-up test was performed and computed tomography scan measured thoracic spinal canal volume. Results. Median SCBF changes were seen 15.8 (5.4-25.1) minutes before MEP loss. However, the 20% threshold interval was often reached before. At the 20% threshold, median pressure was 7psi, balloon volume was 0.5cm3, and 50% of the spinal canal was compromised. In group A, no pigs moved and all had pathology indicating ischemia. In group B, 9 of 10 were found to be moving their hind legs with 7 indicating ischemia. Conclusion. Compression spinal cord injury is the end of a cascade involving increasing intracanal pressure, decreasing canal volume, and hypoperfusion. Rapid relief of compression leads to MEP return. SCBF monitoring can detect ischemia preinjury, giving surgeons an opportunity for early intervention.Level of Evidence: N/A.

AB - Study Design. Porcine model. Objective. To quantify critical vascular and mechanical events that occur before and during an evolving spinal cord injury. Summary of Background Data. Spinal cord injuries are one of the most devastating complications in spine surgery. Intraoperative neuromonitoring changes can occur as a secondary event of spinal cord compression and decrease in spinal cord blood flow (SCBF). Laser Doppler flowmetry has been well validated for measuring blood flow. Methods. Seventeen pigs were studied, 14 of which completed the experiment. Multilevel, midthoracic laminectomies were performed. Laser Doppler flowmetry electrodes were placed on the dura to measure SCBF. Spinal cord injury was induced by incremental balloon inflation in the epidural space. The animals were separated into two groups. After motor-evoked potential (MEP) loss, group A underwent medical interventions and then balloon decompression approximately 20 minutes later. Group B underwent immediate balloon decompression followed by medical interventions. After interventions, wake-up test was performed and computed tomography scan measured thoracic spinal canal volume. Results. Median SCBF changes were seen 15.8 (5.4-25.1) minutes before MEP loss. However, the 20% threshold interval was often reached before. At the 20% threshold, median pressure was 7psi, balloon volume was 0.5cm3, and 50% of the spinal canal was compromised. In group A, no pigs moved and all had pathology indicating ischemia. In group B, 9 of 10 were found to be moving their hind legs with 7 indicating ischemia. Conclusion. Compression spinal cord injury is the end of a cascade involving increasing intracanal pressure, decreasing canal volume, and hypoperfusion. Rapid relief of compression leads to MEP return. SCBF monitoring can detect ischemia preinjury, giving surgeons an opportunity for early intervention.Level of Evidence: N/A.

KW - laminectomy

KW - laser Doppler

KW - motor-evoked potentials

KW - neuromonitoring

KW - spinal canal compromise

KW - spinal cord blood flow

KW - spinal cord injury

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