SSEP review

SSEPs

____ are the most common technique utilized for spinal cord monitoring in IONM

DCML (dorsal column medial lemniscus), fine touch, proprioception, vibration

SSEPs monitor the ___ pathway which is responsible for carrying information related to ____, ____, and ____ sensation

crude touch, pain, and temperature

Information regarding ____, ____, and ______ sensations are carried by the spinothalamic pathway and are not monitored by SSEPs

medulla

The DCML decussates at the ______

dorsal horn gray matter (spinal cord)

The spinothalamic pathway decussates at the _______

ipsilateral

Spinal cord injury to the DCML pathway results in ______ loss of fine touch, proprioception, and vibration below level of the lesion

contralateral

Spinal cord injury to the spinothalamic pathway results in ______ loss of crude touch, pain, and temperature below the level of the lesion

2, 3

The DCML pathway is made up of ___ synapses (medulla and thalamus), and __ orders of neurons

Fasciculus Gracilis

Lower extremity medial portion of DCML pathway

Fasciculus Cuneatus

Upper extremity lateral portion of the DCML pathway

contralateral

Each cerebral hemisphere of the postcentral gyrus contains somatosensory information for the _______ side of the body

rostral, caudal

Signals _____ to the site of injury will be affected, whereas signals ____ to the site would not be affected

technical, perfusion

peripheral SSEP loss can indicate ____ or____ issues

autodromic

ascending DCML pathways

antidromic

descending DCML pathway

reduced amplitude

Stimulation electrodes placed too close together can result in _________ due to shallow current flow and reduced efficacy through salt bridge formation

large artifacts

Stimulation electrodes placed too far apart can result in ________ due to increased impedance and would require more voltage

median

Stimulation sites for the _____ nerve

radial

Stimulation sites for the _____ nerve

ulnar

Stimulation sites for the _____ nerve

median nerve

C5-T1 sensory roots (medial and lateral cords) of the brachial plexus

radial nerve

C5-T1 sensory roots (posterior cord) of the brachial plexus

ulnar nerve

C8-T1 sensory roots (medial cord) of the brachial plexus

200-500, 2.7-4.8, 15-40, 10-30

Recommended stimulation parameters for SSEPs includes:

Pulse width: ______ microsec

Rep Rate: _______ Hz (not integer divisible by 60)

Intensity: _____ mA (pad electrodes), ______ mA (needle electrodes)

CP

SSEP recordings are optimally done at the ___ line

active-reference

A recording channel in which there is an electrode near the generation site (active) and an electrode further away (reference) to allow best common mode rejection/cancellation with the differential amplifier (highly sensitive)

Bipolar

A more specific recording channel in which the active and reference electrodes are both placed near the site of the generator (ex- most EMGs)

Erbs point, C5S or C2S, CPi or Fz, CPc

Recording sites (upper):

Peripheral: _____

Cervical: _____

Subcortical: _____

Cortical: _____

30, 500-1500, 5, 20-500, 10-100, 2-20

SSEP Recording parameters:

Filters: LFF- ____Hz, HFF-____ Hz

Recording epoch/sweep display: ____msec per division (50 msec total)

Average number of trials: _____ runs

Dynamic range/amplifier gain: ____mV/Div

Display gain: _____mV/Div

N20

Cortical upper obligate waveforms

N20, N18, P14, N13, N9

SSEP upper obligate waveforms

N18, P14

subcortical upper SSEP obligate waveforms

N13

cervical upper SSEP obligate waveforms

N9

peripheral upper SSEP obligate waveforms

Posterior tibial

Stimulation sites for the ____ nerve

Peroneal

Stimulation sites for the ____ nerve

femoral

Stimulation sites for the ____ nerve

femoral nerve

L2-L4 sensory roots of the lumbar plexus

peroneal nerve

L4-S2 sensory roots of the lumbosacral plexus

Tibialis nerve

L4-S3 sensory roots of the lumbosacral plexus

200-500, 1.9-4.7, 20-50, 15-40

Lower SSEP stimulation parameters:

Pulse width: ____ msec

Rep-rate: ____ Hz

Intensity: ____mA (pad electrodes), ____ mA (needle electrodes)

pop fossa, T12 or L1, CPc or Fz, CPi or CPz

Lower SSEP recording sites:

Peripheral: _____

Lumbar point: _____

Sub-cortical: ______

Cortical: _____

10

Lower SSEP recording parameters change the sweep display to ____msec per division (100 msec total)

P37, N34, P31, N18, N8

Lower SSEP obligate waveforms:

P37

cortical lower SSEP obligate waveform

N34, P31

subcortical lower SSEP obligate waveforms

N18

Lumbar lower SSEP obligate waveform

N8

Pop fossa/peripheral lower SSEP obligate waveform

inhalational agents

SSEPs may be unreliable with _______ anesthesia regimen

specific to a sensory nerve root

Dermatomal Sensory Evoked Potentials (DSEPs) are similar to SSEPs except that the stimulation is delivered to a specific dermatome making it more ________ rather than a group of nerve roots and DSEPs have lower amplitudes

200-300, 1.9- 4.8, 30-40, 20-30

DSEPs stimulation parameters

pulse width: ____msec

Rep rate:______ Hz

Intensity: _____ mA (pad), ____ mA (needle)

the same

DSEPs have _______ recording parameters and anesthesia regimen to SSEPs