Changes in Muscle Activity in the Early Postoperative Period of Minimally Invasive Orthognathic Surgery

This study aimed to assess the impact of minimally invasive orthognathic surgery on the electromyographic (EMG) activity of the masseter and anterior temporal muscles, using IMPACT, POC, ASYMMETRY, TORSION, and BARYCENTER indices. It also investigated their relationships with postoperative edema and mouth opening. Fifteen patients, with a mean age of 31.3±10.9 years, underwent minimally invasive orthognathic surgery. Surface EMG was performed during maximum dental occlusion, with measurements taken before (T0) and 7 days after surgery (T1). The results indicated a significant reduction in the postoperative POC index of the masseter muscle (P<0.003), suggesting decreased muscle activity following surgery. Correlations were found between the POC index and mouth opening (rs=0.567; P=0.027), indicating functional implications. In addition, associations were observed between facial edema and muscle activity, particularly with the temporal POC index (rs=-0.665; P=0.009) and the Barycentre index (rs=-0.653 to -0.558; P=0.011 to 0.038), indicating changes in muscle position after surgery. This study highlights the significant influence of orthognathic surgery on EMG activity in the masseter and temporal muscles, associated with postoperative edema. Further research is needed to clarify these relationships and develop effective rehabilitation strategies to improve recovery and patient outcomes following surgery.