PROGRESSIVE LATISSIMUS-DORSI MUSCLE DENERVATION FOR FREE-FLAP DYNAMICCARDIOMYOPLASTY

Background: The creation of free muscle grafts for surgical myoplasty is limited by the dependence of muscle on its original nerve supply. T he aim of this study was to develop a model of gradual denervation of a large skeletal muscle (latissimus dorsi) and evaluate the possibilit y that atrophic degeneration and loss of function would be reduced usi ng progressive nerve compression instead of surgical division of the n erve. The effects of chronic stimulation prior to, and after, denervat ion were also evaluated. Methods: Electrodes connected to a myostimula tor were implanted on 24 latissimus dorsi muscles of 12 goats. Denerva tion of these muscles was achieved either by sectioning of the nerve o r by progressive compression using ameroid rings placed around the ner ve. Electrostimulation of the muscle started either 5 weeks before (pr estimulation), or immediately after the denervation. Results: The mode l of gradual nerve compression was successfully created and did have l ess atrophy and loss of function at mid-term when compared with nerve division. Chronic electrostimulation of the muscle after nerve divisio n had a beneficial effect on function and on the atrophic process. Chr onic electrostimulation in our model of gradual nerve compression did not mirror these beneficial results. Detrimental results were observed in groups in which chronic electrostimulation was applied prior to ne rve division or constriction.