Experiment Of Rabbit Masseter Muscle Atrophy Induced By High-Frequency Electric Coagulation Of Small Needle-with Injection Of Botulinum Toxin A

Objection To investigate a new method of minimally invasive treatment of benign masseteric hypertrophy.Methods 60 healthy adult rabbits, weighing 2.14～2.67kg, were randomly divided into 4 group with 25 rabbits in each group. A group of botulinum toxin A injected into masseter muscle, B group of high-frequency electric coagulation effect on the masseter muscle, C group of high-frequency electric coagulation with botulinum toxin A together in the masseter muscle, D group was normal control group. Experimental animals were randomly selected for each side of the masseter muscle as the experimental side, the contralateral side for the self-control. In the experiment 4,8 and 12 weeks, evaluate the masseter muscle atrophy by observation, weigh them, measure the thickness by B-probe and observe the changes under staining microscope, and then compare them with those only injected with botulinum toxin A or only with high-frequency electro coagulation.Results Experimental side masseter general observation:A group of intramuscular injection of botulinum toxin A, B group of high-frequency electric coagulation effect on the masseter muscle, C group of high-frequency electric coagulation with botulinum toxin A together in the masseter muscle, these three interventions are available to the experimental group rabbits side masseter activity decreases, in other words, contractile force decreased and the bite that reduction in the number. Self-control side of experimental rabbits with normal occlusion, experimental side of the masseter muscle is relatively self-control side, the control group the masseter muscle in shape, color, and flexibility eye view of areas did not change significantly. B-probe masseter muscle thickness measurements:the intervention measures to make rabbit masseter muscle thickness decreases in the experimental side, joint action group action group than simply reducing the thickness of the masseter muscle is more obvious, both the differences were statistically significant (P<0.05). Masseter muscle wet weight measurement:cut bilateral masseter muscle in vivo and measured the wet weight, the intervention measures to wet weight of rabbit masseter muscle reduced the experimental side, and the joint action group to make than the simple effect of group living decreased wet weight of masseter muscle is more obvious, both the differences were statistically significant (P<0.05). The muscle fiber were thinner and closely packed in A and C group, while no obvious pathological changes, B and C group showed coagulation zone discontinuity of longitudinal muscle fibers and replace them with machines of the proliferation of fiber woven of fiber necrosis. Coagulation area around the visible portion of the muscle protein degeneration, irregular cell morphology, sarcomere disappeared, and there is no nucleus. C botulinum toxin A group of the role of vision in the organization and the boundaries of high-frequency electric coagulation is more clear.Conclusion The muscle fiber could become much thinner with closely packed, and even necrosis, under high-frequency electro coagulation with botulinum toxin A injection. Masseter muscle being thin, wet weight decreasing, and atrophy of muscle tissue could provide a new experimental study for the clinical treatment of benign masseteric hypertrophy.