This study describes changes in a rat facial muscle innervated by the mandibular and buccal facial nerve branches 4 months after nerve injury and repair. The following groups were studied: (A) normal controls; (B) spontaneous reinnervation by collateral or terminal sprouting; (C) reinnervation after surgical repair of the mandibular branch; and (D) chronic denervation. The normal muscle contained 1200 exclusively fast fibers, mainly myosin heavy chain (MyHC) IIB fibers. In group B, fiber number and fiber type proportions were normal. In group C, fiber number was subnormal. Diameters and proportions of MyHC IIA and hybrid fibers were above normal. The proportion of MyHC IIB fibers was subnormal. Immediate and delayed repair gave similar results with respect to the parameters examined. Group D rats underwent severe atrophic and degenerative changes. Hybrid fibers prevailed. These data suggest that spontaneous regeneration of the rat facial nerve is superior to regeneration after surgical repair and that immediacy does not give better results than moderate delay with respect to surgical repair. Long delays are shown to be detrimental.
Burn surgery has gone through revolutionary changes during the last century, even the most severe burns can now be safely treated. Modern surgical treatments have been followed by improvements in intensive burn care and anaesthesiology. These developments have allowed immediate surgery within 24 hours of the injury to take place in our centre, therefore obtaining advantageous results in shortening hospital stay, improving patient's functional results and simplifying the treatment itself. This treatment is economically beneficial as well. In future we count on rapid development of a new discipline, tissue engineering, which should take a greater role in burn care.
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