Different muscle graft denaturing methods and their use for nerve repair.

In an attempt to enhance recovery through denatured muscle grafts we have used different methods to denature muscle, either using dry heat in a microwave oven or by warming in sterile distilled water. Axonal regeneration was studied at intervals from day 5 to day 60 after insertion of the muscle grafts and compared to results found in frozen-thawed muscle grafts and in autologous nerve grafts used as controls. Axonal regeneration, Schwann cell behaviour and the degree of inflammation were quantified using immunohistochemical techniques and computerised image analysis. Autologous nerve grafts supported the highest rates and volumes of axonal regeneration until day 30 when the microwaved muscle grafts had the highest values for axonal immunostaining and at 60 days the highest level of Schwann cell immunoreactivity. We conclude that microwave heating is suitable as an alternative denaturing method for successful muscle grafts and has a potential clinical use.