ABSTRACT
The purpose of this study was to establish an assay of choline acetyItransferase (ChAT)
activity to investigate the regeneration of injured peripheral nerve, repaired by
end-to-end or end-to-side neurorrha-phy. Murine sciatic and peroneal nerves were exposed,
and the peroneal nerve was transected at a site 5 mm from its ramification. For end-to-side
neurorrhaphy, an epineurotomy producing a 5- × 5-mm window was carried out on the
tibial nerve, just above the level of gastrocnemius muscle ramification. The peroneal
nerve stump was then sutured end-to-side to the tibial nerve window. For end-to-end
neurorrhaphy, the peroneal stump was directly sutured end-to-end. ChAT activity was
measured at a site distal to the peroneal stump at 1 to 3 months postoperatively,
and the results were compared among four groups: 1) end-to-end neurorrhaphy group;
2) end-to-side neurorrhaphy group; 3) unrepaired group; and 4) positive controls.
ChAT activity in the end-to-side neurorrhaphy yielded approximately two-thirds the
value of the end-to-end neurorrhaphy, and more than half the value of positive controls
at 3 months postoperatively. Histologic sections of the end-to-side and end-to-end
sutured peroneal nerve demonstrated large numbers of myelinated axons and Schwann
cells at the third postoperative month. All the results demonstrated that end-to-side
neurorrhaphy is comparable to well-performed end-to-end neurorrhaphy, thus providing
another option for surgical treatment of avulsion nerve injury and massive nerve defect.
