Intraoperative Electroneurodiagnostics (Transcranial Electrical Motor Evoked Potentials) to Evaluate the Functional Status of Anterior Spinal Roots and Spinal Nerves During Brachial Plexus Surgery

✓ Peripheral nerve graft repair after severe brachial plexus injury is futile if there is degeneration of motor fibers in the proximal nerve stump to which the graft must be attached. Traditional intraoperative neurophysiological assessment methods like nerve action potential (NAP) and somatosensory evoked potential (SSEP) monitoring have been used to evaluate proximal nerve stump integrity, but these methods do not allow evaluation of the integrity of motor fibers back to the anterior horn cell. Consequently, the authors used transcranial electrical stimulation and recorded neurogenic motor evoked potentials (MEPs) directly from the brachial plexus in a patient undergoing surgical repair of a complete upper brachial plexus injury (Erb palsy) to assess the functional continuity of motor fibers. In addition, selected elements of the brachial plexus were directly stimulated, and NAPs were recorded. Finally, SSEPs were recorded from the scalp after stimulation of selected elements of the brachial plexus. Neurogenic MEPs were present from the medial cord of the brachial plexus, but not the middle or upper trunk; NAPs were present from the lateral and posterior cords after middle trunk stimulation, but absent after upper trunk stimulation; and SSEPs were present after medial cord stimulation but absent after stimulation of the upper and middle trunks. For the first time, neurogenic MEPs were coupled with NAPs and SSEPs to evaluate successfully the functional status of motor fibers back to the anterior horn cell for accurate localization of the lesion sites.

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Preventing Position-Related Brachial Plexus Injury with Intraoperative Somatosensory Evoked Potentials and Transcranial Electrical Motor Evoked Potentials during Anterior Cervical Spine Surgery

American Journal of Electroneurodiagnostic Technology ◽

10.1080/1086508x.2011.11079820 ◽

2011 ◽

Vol 51 (3) ◽

pp. 198-205 ◽

Cited By ~ 14

Author(s):

Faisal R. Jahangiri ◽

Andrea Flolmberg ◽

Francisco Vega-Bermudez ◽

Vincent Arlet

Keyword(s):

Cervical Spine ◽

Evoked Potentials ◽

Brachial Plexus ◽

Spine Surgery ◽

Somatosensory Evoked Potentials ◽

Brachial Plexus Injury ◽

Motor Evoked Potentials ◽

Cervical Spine Surgery ◽

Anterior Cervical Spine Surgery

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Motor evoked potentials from magnetic stimulation of dorsal spinal roots

Electroencephalography and Clinical Neurophysiology ◽

10.1016/0013-4694(93)90960-4 ◽

1993 ◽

Vol 87 (2) ◽

pp. S30

Author(s):

L. Callea ◽

E. Donati ◽

C. Bargnani

Keyword(s):

Evoked Potentials ◽

Magnetic Stimulation ◽

Motor Evoked Potentials ◽

Spinal Roots ◽

Dorsal Spinal ◽

Stimulation Of

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A cadaveric microanatomical study of the fascicular topography of the brachial plexus

Journal of Neurosurgery ◽

10.3171/2015.6.jns142181 ◽

2016 ◽

Vol 125 (2) ◽

pp. 355-362 ◽

Cited By ~ 7

Author(s):

Sumit Sinha ◽

G. Lakshmi Prasad ◽

Sanjeev Lalwani

Keyword(s):

Brachial Plexus ◽

Suprascapular Nerve ◽

Spinal Nerve ◽

Cross Sectional ◽

Spinal Nerves ◽

Lateral Cord ◽

Total Cross Sectional Area ◽

Anatomical Localization ◽

Intervertebral Foramina ◽

Brachial Plexus Surgery

OBJECT Mapping of the fascicular anatomy of the brachial plexus could provide the nerve surgeon with knowledge of fascicular orientation in spinal nerves of the brachial plexus. This knowledge might improve the surgical outcome of nerve grafting in brachial plexus injuries by anastomosing related fascicles and avoiding possible axonal misrouting. The objective of this study was to map the fascicular topography in the spinal nerves of the brachial plexus. METHODS The entire right-sided brachial plexus of 25 adult male cadavers was dissected, including all 5 spinal nerves (C5–T1), from approximately 5 mm distal to their exit from the intervertebral foramina, to proximal 1 cm of distal branches. All spinal nerves were tagged on the cranial aspect of their circumference using 10-0 nylon suture for orientation. The fascicular dissection of the C5–T1 spinal nerves was performed under microscopic magnification. The area occupied by different nerve fascicles was then expressed as a percentage of the total cross-sectional area of a spinal nerve. RESULTS The localization of fascicular groups was fairly consistent in all spinal nerves. Overall, 4% of the plexus supplies the suprascapular nerve, 31% supplies the medial cord (comprising the ulnar nerve and medial root of the median nerve [MN]), 27.2% supplies the lateral cord (comprising the musculocutaneous nerve and lateral root of the MN), and 37.8% supplies the posterior cord (comprising the axillary and radial nerves). CONCLUSIONS The fascicular dissection and definitive anatomical localization of fascicular groups is feasible in plexal spinal nerves. The knowledge of exact fascicular location might be translatable to the operating room and can be used to anastomose related fascicles in brachial plexus surgery, thereby avoiding the possibility of axonal misrouting and improving the results of plexal reconstruction.

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