The origin of regenerating axons after end-to-side neurorrhaphy without donor nerve injury
ABSTRACT The purpose of this study was to determine the origins of regenerated axons after end-to-side neurorrhaphy (ETSN) without donor nerve injury by comparing the time of appearance of regenerating axons for proximally coapted ETSN and distally coapted ETSN. Thirty rabbits were used in each group. In the proximal ETSN group, the ulnar nerve was transected and the distal end sutured to the median nerve 3cm above the elbow joint, whereas in the distal ETSN group, it was 3cm below the elbow joint. Coaptation was performed by wrapping the aponeurosis of nearby muscle. Observations were made weekly for 6 weeks after ETSN. Axonal regeneration was studied by morphometric analysis and immunohistochemistry. The times of appearance of regenerating axons differed in the proximal and distal ETSN groups. Axonal densities in proximal segments of donor nerves continuously increased and the axonal diameters of proximal segments of donor nerves continuously decreased with time after ETSN. Our findings suggest that regenerated axons after ETSN without donor nerve injury originate from the central nervous system rather than coaptation sites.
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ABSTRACT: Many experimental studies have confirmed collateral sprouting of axons after end-to-side neurorrhaphy and its possible clinical application. There is still controversy about how the surgical method should be carried out. The aim of the present study was to quantitatively evaluate collateral sprouting of motor and sensory axons after end-to-side neurorrhaphy with and without the perineurial window. End-to-side neurorrhaphy of the distal stump of transected musculocutaneous nerve with intact ulnar nerve with or without a perineurial window was performed in a rat model. Collateral sprouts were quantitatively evaluated by counting of motor and sensory neurons following their retrograde labeling by Fluoro-Ruby and Fluoro-Emerald applied to the ulnar and musculocutaneous nerves, respectively. Our results show that significantly more motor and sensory axons sent their collateral branches into the recipient nerve in the group with a perineurial window. Some axons were injured during preparation of the perineurial window; the injured axons reinnervated directly into the recipient nerve to contribute to results of functional reinnervation. The authors conclude that it is necessary to create a perineurial window when using end-to-side neurorrhaphy in clinical practice, especially in brachial plexus reconstruction.Plastic and Reconstructive Surgery 09/2012; 130(3):609-14. DOI:10.1097/PRS.0b013e31825dc20a · 3.33 Impact Factor