Side-to-side nerve bridges reduce muscle atrophy after peripheral nerve injury in a rodent model.
BACKGROUND
Peripheral nerve injury can result in muscle atrophy and long-term disability. We hypothesize that creating a side-to-side bridge to link an injured nerve with a healthy nerve will reduce muscle atrophy and improve muscle function.


METHODS
Sprague-Dawley rats were divided into four groups (n = 7 per group). Group 1: transection only--a 10-mm gap was created in the proximal tibial nerve; group 2: transected plus repaired--the transected tibial nerve was repaired; group 3: transected plus repaired plus nerve bridge--transected nerve repaired with a distal nerve bridge between the tibial and peroneal nerves via epineurial windows; and group 4: transected plus nerve bridge--transected tibial nerve left unrepaired and distal bridge added. Gait was assessed every 2 wk. At 90 d the following measures were determined: gastrocnemius mass, muscle and nerve nuclear density, and axonal infiltration into the nerve bridge.


RESULTS
Groups 3 and 4 had greater improvements in walking track recovery than groups 1 and 2. Group 3's gastrocnemius muscles exhibited the least amount of atrophy. Groups 1, 2, and 4 exhibited greater histologic appearance of muscle breakdown compared with group 3 and control muscle. Finally, most bridges in groups 3 and 4 had neuronal sprouting via the epineurial windows.


CONCLUSIONS
Our study demonstrated reduced muscle atrophy with a side-to-side nerve bridge in the setting of peripheral nerve injury. These results support the application of novel side-to-side bridges in combination with traditional end-to-end neurorrhaphy to preserve muscle viability after peripheral nerve injuries.
Department of Surgery, Division of General Surgery, University of Utah School of Medicine, Salt Lake City, Utah.
Jill E
JE
Shea
University of Utah School of Medicine, Salt Lake City, Utah.
Jared W
JW
Garlick
University of Utah School of Medicine, Salt Lake City, Utah; ARUP Reference Laboratory Research Institute, Salt Lake City, Utah.
Mohamed E
ME
Salama
The Institute for Plastic Surgery, Southern Illinois University School of Medicine, Springfield, Illinois.
Shaun D
SD
Mendenhall
University of Utah School of Medicine, Salt Lake City, Utah.
Linh A
LA
Moran
Department of Surgery, Division of Plastic and Reconstructive Surgery, University of Utah School of Medicine, Salt Lake City, Utah. Electronic address: jay.agarwal@hsc.utah.edu.
Jayant P
JP
Agarwal
D000818:Animals; D001284:Atrophy; D004195:Disease Models, Animal; D008297:Male; D018482:Muscle, Skeletal / Q000294:innervation* / Q000473:pathology; D009133:Muscular Atrophy / Q000473:pathology / Q000601:surgery*; D009416:Nerve Regeneration; D016067:Nerve Transfer / Q000379:methods*; D059348:Peripheral Nerve Injuries / Q000473:pathology / Q000601:surgery*; D010543:Peroneal Nerve / Q000601:surgery*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013979:Tibial Nerve / Q000293:injuries / Q000601:surgery*
Nerve injury; Nerve repair; Peripheral nerve