Long-term evaluation of rabbit peripheral nerve repair with end-to-side neurorrh

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Microsurgery. 2006 Apr 20

Long-term evaluation of rabbit peripheral nerve repair with end-to-

side neurorrhaphy in rabbits.

Zhang Z, EO, Vekris MD, Zoubos AB, Bo J, Beris AE, Soucacos

PN.

Department of Orthopedic Surgery, School of Medicine, University of

Athens, Athens, Greece.

This study was designed to quantitatively assess long-term end-to-

side neurorrhaphy in rabbits. The cut right ulnar nerve was repaired

and sutured to the median nerve, in which a perineurial window was

created in an end-to-side fashion 3 cm above the elbow joint. Both

the extent of the reinnervation and the integrity of the intact donor

nerve were evaluated in 36 rabbits randomly treated with fresh or

delayed nerve repair. Evaluations included motor nerve conduction

velocity (MNCV), dry muscle weight (DMW), and histological

examinations at 9 and 12 months postoperatively. The recovery rates

of MNCV were 90.1% and 92.8% for the ulnar nerve, and 95.7% and 96.8%

for the median nerve, compared to intact contralateral nerves at 9

and 12 months, respectively.

MNCV was not detectable for the ulnar nerve in control animals, while

it was normal for the median nerve. Recoveries of flexor carpi

ulnaris dry muscle weight of about 90.7% and 94.5% were observed at 9

and 12 months postoperatively, respectively. However, muscle mass

measurements revealed a recovery of only 31

..3% and 27% for control groups at 9 and 12 months postoperatively.

The differences between experimental groups and control groups were

statistically significant (P < 0.01). Neurofilament and silver stains

showed numerous sprouting axons originating from the median nerve to

the ulnar nerve.

The results indicate that end-to-side neurorrhaphy could induce

axonal sprouting from the main nerve trunk of upper limbs in rabbits,

leading to useful functional recovery.