The Clinical Study On The Treatment Of Late Facial Paralysis With Free Muscle Flap Of Neurovascular Gracilis Muscle

Objective To explore the clinical application of the free muscle flap of neurovascular gracilis muscle in late facial paralysis,including the selection of donor nerves,recipient vessels and postoperative effect and so on.Methods From February 2012 to June 2019,a total of 50 patients with facial paralysis caused by different causes were admitted.After applying the above-mentioned inclusion and exclusion criteria,17 patients with late facial paralysis receiving a free functional muscle transfer for facial reanimation surgery were retrospectively analysed,including 8 males and 9 females at the age of 13-46 with an average of 23 years old.Coaptation to a CFNG was performed in 12 patients and to the motor branch of the masseter muscle in 5 patients.The operation of the cross-facial nerve graft group was divided into two stages.The cross-facial nerve graft was performed in the first stage,followed by free gracilis transfer in the second stage.The operation of masseter nerve group was completed in one stage,and the gracilis nerve was directly anastomosed with the masseter nerve.Through the follow-up of patients,we evaluate the postoperative treatment effect of late facial paralysis.The evaluation criteria were based on a modified version of the House-Brackmann grading scale to evaluate the postoperative movements of the patients’ corners of the mouth:grade Ⅰ and Ⅱ were excellent,grade Ⅲ and Ⅳ were good,grade Ⅴ was fair,and grade Ⅵ was poor.Patients were also asked about their satisfaction with the operation.In addition,we also conducted an objective test to evaluate the improvement of the patient’ s postoperative angle by measuring the angle formed between the horizontal line of the bilateral mouth angle and the vertical midline in the patient’ s preoperative and postoperative photos.Results 17 patients were followed up for 1Y-7Y by face-to-face visit or network.One patient complained of no effect after operation and venous thrombosis of lower extremity.After sural nerve resection,1 patient felt numbness in the left heel area and was more prone to fatigue and acid swelling than the contralateral side after walking for a long time,which was relieved spontaneously without any treatment.3 patients underwent three-stage surgery to improve local skin treatment.The rest of the patients achieved good results,with basically symmetrical static and dynamic faces,because of which they were satisfied with the surgical effect.The movement of the corners of mouth was classified as excellent in 13 cases,good in 3 cases and fair in 1 case.The range of postoperative static angle improvement compared with preoperative:3° to 10°,with an average improvement of 6°;dynamic angle improvement range:4°~15°,with an average improvement of 9°.Conclusion The free muscle flap of neurovascular gracilis can be used for the treatment of late facial paralysis,which is of great significance for the reconstruction of facial dynamics in patients with late facial paralysis.The number of nerve axons and the weight of the muscle determine the power of the transplanted muscle,which in turn determine the final degree of postoperative facial recovery.The application of cross-facial nerve graft can make the patients obtain the cooperative smile on both sides of the face;although the application of masseter nerve can obtain the strong movement on the affected side,the synergetic ability of both sides of the face is poor,and the functional exercise of the face after surgery is very important.After six months to one year of functional training,the synergetic effect of the face can be improved.The blood vessels are preferably anastomosed with facial artery and facial vein,which can effectively improve the dynamics of the affected side.Later treatment is an individualized choice.After transplanting the gracilis,patients who are dissatisfied with the appearance may be further surgically treated.