Department of Plastic and Hand Surgery, University of Freiburg Medical Centre, Faculty of Medicine, University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany.
Department of Plastic and Hand Surgery, University of Freiburg Medical Centre, Faculty of Medicine, University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany.
J Plast Reconstr Aesthet Surg. 2019 Mar;72(3):505-512. doi: 10.1016/j.bjps.2018.11.011. Epub 2018 Nov 22.
Synchronicity of the oral commissure movement of a bilateral smile is a significant goal for reconstruction in facial reanimation and may only be guaranteed with use of the facial nerve as a donor nerve. Yet over the years several studies report some degree of spontaneity in certain patients when using a non-facial donor nerve, which indicates that synchronous initiation of the smile might be achievable with other donor nerves. We designed a prospective cohort study to evaluate whether pre-operative involuntary activation of the masseteric nerve during smile predicts development of a synchronous smile development when using the masseteric nerve for reanimation.
In a prospective cohort study unilateral long-standing facial palsy patients scheduled for dynamic smile reanimation with a free functional muscle transplant using the masseteric nerve as a donor nerve were preoperatively evaluated via EMG for involuntary activation of the masseter muscle upon smiling, which we called coactivation. Postoperatively, six months after noting the first muscle contraction smile synchronicity was evaluated. We analyzed the synchronicity of the bilateral smile development by analyzing slow-motion video sequences of the patients that were taken while the patients were watching funny video sequences. Results were then correlated with the pre-operative EMG.
30 patients were recruited for this prospective study and underwent facial reanimation surgery with a free gracilis transfer innervated by the masseteric nerve. 19 patients demonstrated involuntary coactivation of the masseter muscle upon smiling and 11 did not. Postoperatively all patients could demonstrate a voluntary smile. 94% of patients who had preoperative coactivation showed a synchronous movement of the oral commissure when smiling. In those patients, that did not show activation of the masseter muscle upon smiling 0% showed synchronicity. The preoperative coactivation of the masseter muscle is able to predict the outcome regarding synchronicity of the smile with a sensitivity of 99.7%, a specificity of 88.5% and 92.5% positive predictive value and 99.6% negative predictive value (p < 0.001 for all).
The lack of masseter co-activation with smile predicts a lack of spontaneous involuntary smile after dynamic smile reconstruction using the masseteric nerve.
双侧微笑时口角运动的同步性是面部再运动的一个重要目标，只有使用面神经作为供体神经才能保证。然而，多年来，一些研究报告称，在使用非面神经供体神经的某些患者中，存在一定程度的自发性，这表明其他供体神经也可以实现微笑的同步启动。我们设计了一项前瞻性队列研究，以评估在使用咬肌神经进行再运动时，微笑时咬肌神经的预发性非自愿激活是否预示着同步微笑的发展。
在一项前瞻性队列研究中，我们对单侧长期面瘫患者进行评估，这些患者计划使用咬肌神经作为供体神经进行游离功能性肌肉移植进行动态微笑再运动。在术前，通过肌电图评估微笑时咬肌的非自愿激活，我们称之为共激活。术后 6 个月，在记录到第一次肌肉收缩微笑同步性后进行评估。我们通过分析患者观看有趣视频序列时拍摄的患者慢动作视频序列来分析双侧微笑发展的同步性。结果与术前肌电图相关。
这项前瞻性研究共招募了 30 名患者，进行了游离股薄肌移植的面部再运动手术，由咬肌神经支配。19 名患者在微笑时表现出咬肌的非自愿共激活，而 11 名患者没有。术后所有患者都能表现出自愿的微笑。在术前有共激活的患者中，94%在微笑时表现出口角运动的同步性。在那些微笑时没有表现出咬肌肌肉激活的患者中，没有出现同步性。微笑时咬肌的预发性共激活能够预测微笑同步性的结果，其灵敏度为 99.7%，特异性为 88.5%，阳性预测值为 92.5%，阴性预测值为 99.6%（均<0.001）。
微笑时没有咬肌共激活预示着使用咬肌神经进行动态微笑重建后，自发性非自愿微笑的缺乏。
