Fluorescent retrograde axonal tracing of the facial nerve.
OBJECTIVE
The objective of this study was to investigate retrograde fluorescent axonal labeling of motor nerves as an aid to surgical dissection in otolaryngology-head and neck surgery.


METHODS
Cholera toxin B subunit conjugated to a fluorescent dye was injected into the facial musculature of New Zealand white rabbits. At variable time points after injection, the facial nerves were harvested and analyzed for fluorescence in the peripheral axon.


RESULTS
All injected animals demonstrated axonal fluorescence. No animal demonstrated facial weakness. Fluorescence was detected a maximum of 20 mm from the distal end of the nerve. Time periods greater than 48 hours did not substantially increase transport distance.


CONCLUSIONS
Cholera toxin B subunit fluorescent conjugates, when administered intramuscularly, reliably label the distal portion of the facial nerve. In vivo labeling of a motor nerve may have significant potential for identifying a nerve in surgery. This work represents a preliminary investigation into the adaptation of in vivo fluorescence techniques as an aid to surgical dissection. Further research to refine this technique should be supported.
O'Malley
Matthew R
MR
Vanderbilt University Department of Hearing and Speech Sciences, Nashville, Tennessee, USA. matthew.o.malley@vanderbilt.edu
Wittkopf
Justin E
JE
Cutler
Jeffrey L
JL
Labadie
Robert F
RF
Hackett
Troy A
TA
Haynes
David S
DS
D000818:Animals; D001369:Axons / Q000648:ultrastructure*; D002772:Cholera Toxin; D005152:Facial Muscles / Q000294:innervation; D005154:Facial Nerve / Q000033:anatomy & histology*; D005260:Female; D005456:Fluorescent Dyes; D007091:Image Processing, Computer-Assisted; D007273:Injections, Intramuscular; D008297:Male; D008856:Microscopy, Fluorescence; D009046:Motor Neurons / Q000166:cytology*; D009434:Neural Pathways / Q000033:anatomy & histology; D011817:Rabbits; D013997:Time Factors
D005456:Fluorescent Dyes; D002772:Cholera Toxin