Intrathecal bupivacaine protects against extension of lesions in an acute photochemical spinal cord injury model.
OBJECTIVE
The photochemical spinal-cord injury model reproduces extensive secondary lesions that occur after spinal injury. We have evaluated in 27 rats the functional, electrophysiological and anatomical consequences of a photochemical spinal-cord lesion induced before or after intrathecal injection of bupivacaine.


METHODS
After randomization, nine rats received 20 micro L of intrathecal bupivacaine 0.5% 15 min before a photochemical spinal-cord lesion (Group I) and eight rats received 20 micro L intrathecal bupivacaine 15 min after such a lesion (Group II). Ten rats received 20 micro L of saline 15 min before the photochemical injury (control group). Paraplegia was tested on days one, three, five, seven, nine, 12, 15 and 18 using an evaluation of hindlimb movements and an inclined plane stability test. Sensory block was evaluated by the animal's response when each hindlimb was brought into contact with a hot plate. Sympathetic injury was evaluated in terms of bladder voiding dysfunction. On day 18, residual somatosensory evoked potentials (SEP) were measured and the area of the intact spinal cord was determined using a digitalized system.


RESULTS
Early paraplegia recovery was found in the two bupivacaine groups (P < 0.05). On day 12, motor recovery was complete in both bupivacaine groups whereas recovery was not complete on day 18 in the control group. Compared to the control group, inclined plane stability recovered earlier in Groups I and II, from day three to day 15. Sensory and sympathetic block scores were not different in the three groups. Nevertheless, SEP latencies were longer and amplitudes were lower in control group rats compared with the two bupivacaine groups on day 18. The intact spinal-cord cross-sectional area around the lesion was not different in the three groups.


CONCLUSIONS
Twenty microlitres of intrathecal bupivacaine before or after acute photochemical spinal injury improves hindlimb motor recovery and SEP parameters in rats.
Lopez
Sandrine
S
Department of Anesthesiology and Critical Care Medicine, Lapeyronie University Hospital, Montpellier, France.
Privat
Alain
A
Bernard
Nathalie
N
Ohanna
Freddy
F
Vergnes
Christine
C
Capdevila
Xavier
X
D000779:Anesthetics, Local / Q000008:administration & dosage / Q000627:therapeutic use*; D000818:Animals; D002045:Bupivacaine / Q000008:administration & dosage / Q000627:therapeutic use*; D004195:Disease Models, Animal; D018450:Disease Progression; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects; D007278:Injections, Spinal; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D018696:Neuroprotective Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D010777:Photochemistry; D011446:Prospective Studies; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000473:pathology; D013119:Spinal Cord Injuries / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D018709:Statistics, Nonparametric; D013997:Time Factors; D016896:Treatment Outcome
D000779:Anesthetics, Local; D018696:Neuroprotective Agents; D002045:Bupivacaine