Behavior of the H-reflex in humans following mechanical perturbation or injury to rostral spinal cord.
In humans H-reflexes are suppressed during early spinal shock. In animals rostral cord injury results in loss of segmental reflexes within seconds. If H-reflexes persist under general anesthesia, can they be used to monitor the integrity of the rostral cord? In part I of this study, we recorded H-reflexes intraoperatively in 25 patients to elucidate general anesthesia effect. In 23 subjects, H-reflexes were consistently elicited, and within +/- 13% of the normalized group mean amplitude. In part II, we recorded H-reflexes in 31 patients during spinal cord surgery to elucidate H-reflex behavior immediately following rostral spinal cord injury. In 6, abrupt suppression of the H-reflex coincided with cord injury. In 4 of 6, suppression was transient and less than 50% of baseline; none of these patients developed neurological deficits. In 2, suppression exceeded 90% and persisted throughout surgery; both patients developed profound deficits. We conclude that (1) the H-reflex can be consistently elicited under general anesthesia in most patients, (2) rostral cord injury rapidly suppresses the H-reflex, and (3) the degree and duration of H-reflex suppression reflects the severity of the injury.
Leis
A A
AA
Department of Neurology, University of Mississippi Medical Center, Jackson, USA.
Zhou
H H
HH
Mehta
M
M
Harkey
H L
HL
Paske
W C
WC
D000293:Adolescent; D000328:Adult; D000768:Anesthesia, General; D005260:Female; D006181:H-Reflex; D006801:Humans; D007432:Intraoperative Period; D007530:Isoflurane; D008297:Male; D008875:Middle Aged; D009609:Nitrous Oxide; D012720:Severity of Illness Index; D013116:Spinal Cord / Q000503:physiopathology*; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D013314:Stress, Mechanical; D013997:Time Factors
D007530:Isoflurane; D009609:Nitrous Oxide