Bipolar electrocautery: A rodent model of Sunderland third-degree nerve injury.
OBJECTIVE
To determine the Sunderland classification of a bipolar electrocautery injury.


METHODS
Twenty-two rats received crush (a reproducible Sunderland second-degree injury) or bipolar electrocautery injury and were evaluated for functional, histomorphometric, and immunohistochemical recovery at 21 or 42 days. Animal experiments were performed between July 3 and December 12, 2007. Axonal regeneration and end plate reinnervation were evaluated in double transgenic cyan fluorescent protein-conjugated Thy1 and green fluorescent protein-conjugated S100 mice.


RESULTS
Compared with crush injury, bipolar electrocautery injury caused greater disruption of myelin and neurofilament architecture at the injury site and decreased nerve fiber counts and percentage of neural tissue distal to the injury (P =.007). Complete functional recovery was seen after crush but not bipolar electrocautery injury. Serial live imaging demonstrated axonal regeneration at week 1 after crush and at week 3 after bipolar electrocautery injury. Qualitative assessment of motor end plate reinnervation at 42 days demonstrated complete neuromuscular end plate reinnervation in the crush group and only limited reinnervation in the bipolar electrocautery group.


CONCLUSIONS
Bipolar electrocautery injury in a rodent model resulted in a Sunderland third-degree injury, characterized by gradual, incomplete recovery without intervention.
Moradzadeh
Arash
A
Department of Otolaryngology-Head & Neck Surgery, Washington University School of Medicine, St Louis, Missouri, USA.
Brenner
Michael J
MJ
Whitlock
Elizabeth L
EL
Tong
Alice Y
AY
Luciano
Janina P
JP
Hunter
Daniel A
DA
Myckatyn
Terence M
TM
Mackinnon
Susan E
SE
D000818:Animals; D004564:Electrocoagulation / Q000379:methods*; D008297:Male; D051379:Mice; D059348:Peripheral Nerve Injuries; D010525:Peripheral Nerves / Q000473:pathology / Q000601:surgery*; D051381:Rats; D011917:Rats, Inbred Lew; D019651:Plastic Surgery Procedures / Q000379:methods*; D012720:Severity of Illness Index