Intraoperative neurophysiologic discovery of uncrossed sensory and motor pathways in a patient with horizontal gaze palsy and scoliosis

D. B. MacDonald, Leopold Streletz, Z. Al-Zayed, S. Abdool, B. Stigsby

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

Objective: To report the intraoperative neurophysiologic discovery of clinically unsuspected non-decussation of the somatosensory and motor pathways. Methods: We performed somatosensory evoked potential (SEP) and transcranial electric stimulation (TES) muscle motor evoked potential (MEP) monitoring during scoliosis surgery for a 16 year old patient with familial horizontal gaze palsy and progressive scoliosis. Our routine procedures included optimizing tibial cortical SEP monitoring derivations through saggital and coronal (C4′, C2′, Cz′, C1′, C3′-mastoid) P37 mapping, which surprisingly indicated non-decussation. Consequently, we also obtained coronal median nerve SEPs and simultaneous bilateral muscle recordings to lateralized TES (C3-Cz, C4-Cz) intraoperatively and focal hand area transcranial magnetic stimulation (TMS) postoperatively. Results: For each nerve, tibial P37/N37 distribution was contralateral/ipsilateral and median N20 ipsilateral. For each hemisphere, ipsilateral TES MEPs had lower thresholds and TMS MEPs were exclusively ipsilateral. Accurate monitoring required reversed montages. Reevaluation of an MRI (previously reported normal) disclosed a ventral midline cleft of the medulla. Conclusions: The results indicate uncrossed dorsal column-medial lemniscal and corticospinal pathways due to brain-stem malformation with absent internal arcuate and pyramidal decussations. Significance: Simultaneous bilateral recording to unilateral stimulation demonstrates SEP/MEP hemispheric origin and is important for accurate interpretation and monitoring because decussation anomalies exist.

Original languageEnglish
Pages (from-to)576-582
Number of pages7
JournalClinical Neurophysiology
Volume115
Issue number3
DOIs
Publication statusPublished - Mar 2004
Externally publishedYes

Fingerprint

Efferent Pathways
Somatosensory Evoked Potentials
Scoliosis
Paralysis
Electric Stimulation
Motor Evoked Potentials
Transcranial Magnetic Stimulation
Muscles
Tibial Nerve
Pyramidal Tracts
Mastoid
Median Nerve
Brain Stem
Hand

Keywords

  • Brain-stem malformation
  • Horizontal gaze palsy
  • Intraoperative monitoring
  • Motor evoked potentials
  • Scoliosis
  • Somatosensory evoked potentials
  • Uncrossed sensorimotor pathways

ASJC Scopus subject areas

  • Clinical Neurology
  • Radiology Nuclear Medicine and imaging
  • Neurology
  • Sensory Systems
  • Physiology (medical)

Cite this

Intraoperative neurophysiologic discovery of uncrossed sensory and motor pathways in a patient with horizontal gaze palsy and scoliosis. / MacDonald, D. B.; Streletz, Leopold; Al-Zayed, Z.; Abdool, S.; Stigsby, B.

In: Clinical Neurophysiology, Vol. 115, No. 3, 03.2004, p. 576-582.

Research output: Contribution to journalArticle

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