Somatosensory evoked potential monitoring detection of carotid compression during ACDF surgery in a patient with a vascularly isolated hemisphere

Alan D. Legatt, Avra S. Laarakker, Jonathan P. Nakhla, Rani Nasser, David J. Altschul

Research output: Contribution to journalArticle

Abstract

The authors report herein a case of anterior cervical discectomy and fusion (ACDF) surgery in which findings on somatosensory evoked potential (SSEP) monitoring led to the correction of carotid artery compression in a patient with a vascularly isolated hemisphere (no significant collateral blood vessels to the carotid artery territory). The amplitude of the cortical SSEP component to left ulnar nerve stimulation progressively decreased in multiple runs, but there were no changes in the cervicomedullary SSEP component to the same stimulus. When the lateral (right-sided) retractor was removed, the cortical SSEP component returned to baseline. The retraction was then intermittently relaxed during the rest of the operation, and the patient suffered no neurological morbidity. Magnetic resonance angiography demonstrated a vascularly isolated right hemisphere. During anterior cervical spine surgery, carotid artery compression by the retractor can cause hemispheric ischemia and infarction in patients with inadequate collateral circulation. The primary purpose of SSEP monitoring during ACDF surgery is to detect compromise of the dorsal column somatosensory pathways within the cervical spinal cord, but intraoperative SSEP monitoring can also detect hemispheric ischemia. Concurrent recording of cervicomedullary SSEPs can help differentiate cortical SSEP changes due to hemispheric ischemia from those due to compromise of the dorsal column pathways. If there are adverse changes in the cortical SSEPs but no changes in the cervicomedullary SSEPs, the possibility of hemispheric ischemia due to carotid artery compression by the retractor should be considered.

Original languageEnglish (US)
Pages (from-to)566-571
Number of pages6
JournalJournal of neurosurgery. Spine
Volume25
Issue number5
StatePublished - Nov 1 2016

Fingerprint

Diskectomy
Somatosensory Evoked Potentials
Carotid Arteries
Ischemia
Collateral Circulation
Ulnar Nerve
Magnetic Resonance Angiography
Infarction
Blood Vessels
Spine
Morbidity

Keywords

  • ACDF = anterior cervical discectomy and fusion
  • ACoA = anterior communicating artery
  • anterior cervical discectomy and fusion
  • BP = blood pressure
  • carotid artery compression
  • CCA = common carotid artery
  • circle of Willis
  • EMG = electromyographic
  • ICA = internal carotid artery
  • intraoperative neurophysiological monitoring
  • IOM = intraoperative monitoring
  • isolated hemisphere
  • MEP = motor evoked potential
  • MRA = MR angiogram
  • PCA = posterior cerebral artery
  • PCoA = posterior communicating artery
  • somatosensory evoked potentials
  • SSEP = somatosensory evoked potential
  • technique
  • TES = transcranial electrical stimulation

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Somatosensory evoked potential monitoring detection of carotid compression during ACDF surgery in a patient with a vascularly isolated hemisphere. / Legatt, Alan D.; Laarakker, Avra S.; Nakhla, Jonathan P.; Nasser, Rani; Altschul, David J.

In: Journal of neurosurgery. Spine, Vol. 25, No. 5, 01.11.2016, p. 566-571.

Research output: Contribution to journalArticle

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abstract = "The authors report herein a case of anterior cervical discectomy and fusion (ACDF) surgery in which findings on somatosensory evoked potential (SSEP) monitoring led to the correction of carotid artery compression in a patient with a vascularly isolated hemisphere (no significant collateral blood vessels to the carotid artery territory). The amplitude of the cortical SSEP component to left ulnar nerve stimulation progressively decreased in multiple runs, but there were no changes in the cervicomedullary SSEP component to the same stimulus. When the lateral (right-sided) retractor was removed, the cortical SSEP component returned to baseline. The retraction was then intermittently relaxed during the rest of the operation, and the patient suffered no neurological morbidity. Magnetic resonance angiography demonstrated a vascularly isolated right hemisphere. During anterior cervical spine surgery, carotid artery compression by the retractor can cause hemispheric ischemia and infarction in patients with inadequate collateral circulation. The primary purpose of SSEP monitoring during ACDF surgery is to detect compromise of the dorsal column somatosensory pathways within the cervical spinal cord, but intraoperative SSEP monitoring can also detect hemispheric ischemia. Concurrent recording of cervicomedullary SSEPs can help differentiate cortical SSEP changes due to hemispheric ischemia from those due to compromise of the dorsal column pathways. If there are adverse changes in the cortical SSEPs but no changes in the cervicomedullary SSEPs, the possibility of hemispheric ischemia due to carotid artery compression by the retractor should be considered.",
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T1 - Somatosensory evoked potential monitoring detection of carotid compression during ACDF surgery in a patient with a vascularly isolated hemisphere

AU - Legatt, Alan D.

AU - Laarakker, Avra S.

AU - Nakhla, Jonathan P.

AU - Nasser, Rani

AU - Altschul, David J.

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N2 - The authors report herein a case of anterior cervical discectomy and fusion (ACDF) surgery in which findings on somatosensory evoked potential (SSEP) monitoring led to the correction of carotid artery compression in a patient with a vascularly isolated hemisphere (no significant collateral blood vessels to the carotid artery territory). The amplitude of the cortical SSEP component to left ulnar nerve stimulation progressively decreased in multiple runs, but there were no changes in the cervicomedullary SSEP component to the same stimulus. When the lateral (right-sided) retractor was removed, the cortical SSEP component returned to baseline. The retraction was then intermittently relaxed during the rest of the operation, and the patient suffered no neurological morbidity. Magnetic resonance angiography demonstrated a vascularly isolated right hemisphere. During anterior cervical spine surgery, carotid artery compression by the retractor can cause hemispheric ischemia and infarction in patients with inadequate collateral circulation. The primary purpose of SSEP monitoring during ACDF surgery is to detect compromise of the dorsal column somatosensory pathways within the cervical spinal cord, but intraoperative SSEP monitoring can also detect hemispheric ischemia. Concurrent recording of cervicomedullary SSEPs can help differentiate cortical SSEP changes due to hemispheric ischemia from those due to compromise of the dorsal column pathways. If there are adverse changes in the cortical SSEPs but no changes in the cervicomedullary SSEPs, the possibility of hemispheric ischemia due to carotid artery compression by the retractor should be considered.

AB - The authors report herein a case of anterior cervical discectomy and fusion (ACDF) surgery in which findings on somatosensory evoked potential (SSEP) monitoring led to the correction of carotid artery compression in a patient with a vascularly isolated hemisphere (no significant collateral blood vessels to the carotid artery territory). The amplitude of the cortical SSEP component to left ulnar nerve stimulation progressively decreased in multiple runs, but there were no changes in the cervicomedullary SSEP component to the same stimulus. When the lateral (right-sided) retractor was removed, the cortical SSEP component returned to baseline. The retraction was then intermittently relaxed during the rest of the operation, and the patient suffered no neurological morbidity. Magnetic resonance angiography demonstrated a vascularly isolated right hemisphere. During anterior cervical spine surgery, carotid artery compression by the retractor can cause hemispheric ischemia and infarction in patients with inadequate collateral circulation. The primary purpose of SSEP monitoring during ACDF surgery is to detect compromise of the dorsal column somatosensory pathways within the cervical spinal cord, but intraoperative SSEP monitoring can also detect hemispheric ischemia. Concurrent recording of cervicomedullary SSEPs can help differentiate cortical SSEP changes due to hemispheric ischemia from those due to compromise of the dorsal column pathways. If there are adverse changes in the cortical SSEPs but no changes in the cervicomedullary SSEPs, the possibility of hemispheric ischemia due to carotid artery compression by the retractor should be considered.

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KW - ACoA = anterior communicating artery

KW - anterior cervical discectomy and fusion

KW - BP = blood pressure

KW - carotid artery compression

KW - CCA = common carotid artery

KW - circle of Willis

KW - EMG = electromyographic

KW - ICA = internal carotid artery

KW - intraoperative neurophysiological monitoring

KW - IOM = intraoperative monitoring

KW - isolated hemisphere

KW - MEP = motor evoked potential

KW - MRA = MR angiogram

KW - PCA = posterior cerebral artery

KW - PCoA = posterior communicating artery

KW - somatosensory evoked potentials

KW - SSEP = somatosensory evoked potential

KW - technique

KW - TES = transcranial electrical stimulation

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