Intraoperative lower extremity reflex muscle activity as an adjunct to conventional somatosensory-evoked potentials and descending neurogenic monitoring in idiopathic scoliosis.
METHODS
Lower extremity polysynaptic reflexes and descending neurogenic motor and ascending somatosensory activity were recorded.


OBJECTIVE
Two cases are presented to illustrate the intraoperative use of lower extremity reflex recordings for detecting compromise of spinal cord function.


BACKGROUND
Lower extremity reflex processing can be used to measure integrated spinal cord activity, whereas descending neurogenic and ascending somatosensory potentials measure only long tract function.


METHODS
Eight channels of lower extremity polysynaptic reflex activity were recorded simultaneously after unilateral lower extremity mixed nerve stimulation. Sequential descending neurogenic and ascending somatosensory activity was recorded simultaneously with reflex recordings.


RESULTS
In these two patients with idiopathic scoliosis, intraoperative reflexes changed before descending neurogenic and before ascending somatosensory activity changed. High-amplitude synchronous persistent reflex activity correlated with a postoperative neurologic deficit. Low-amplitude asynchronous transient reflex activity was not associated with a postoperative neurologic deficit.


CONCLUSIONS
Intraoperative lower extremity reflex changes are more sensitive to spinal cord compromise than are changes in long tract function. Lower extremity polysynaptic reflexes monitor the integrated activity of the spinal cord that is responsible for the control of complex motor behavior.
Leppanen
R
R
Knoxville Neurology Clinic, St. Mary's Medical Center, Tennessee, USA.
Maguire
J
J
Wallace
S
S
Madigan
R
R
Draper
V
V
D000293:Adolescent; D002648:Child; D005071:Evoked Potentials / Q000502:physiology; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005260:Female; D006801:Humans; D007866:Leg; D016343:Monitoring, Intraoperative; D018482:Muscle, Skeletal / Q000294:innervation* / Q000502:physiology; D012018:Reflex / Q000502:physiology*; D012600:Scoliosis / Q000503:physiopathology* / Q000601:surgery; D013116:Spinal Cord / Q000503:physiopathology*