Muscle Flap Reconstruction Based on Muscle Tension Line Groups to Repair the Philtrum of Patients With Microform Cleft Lip or Secondary Cleft Lip

The muscle flap reconstruction technique was developed based on the concept of muscle tension line groups, which elucidates how nasolabial muscle tension helps maintain the shape of the philtrum. To investigate the operative effect, we reviewed 43 patients with microform cleft lip and 102 patients with secondary cleft lip treated with muscle flap reconstruction between January 2018 and June 2020. The patients were scanned using the digital three-dimensional stereophotogrammetry face system pre- and post-operatively, and comparative analysis of three-dimensional (3D) images was used to highlight variations of the philtrum. Visual analog scales were used to assess surgical outcomes. More than 6 months after the surgery, comparative 3D images of 37 patients (86.04%) with microform cleft lip and 86 patients (84.31%) with secondary cleft lip showed visible improvement in the prominence of the affected column. In addition, visual analog scale scores showed that 38 microform cleft lip patients (88.37%) and 89 secondary cleft lip patients (87.25%) had a good appearance. The postoperative prominence of the philtral column in both groups improved significantly compared to before surgery (P < 0.001 and P < 0.001, respectively). There was no significant difference in scores for philtrum prominence pre- and post-operatively between the 2 groups (P > 0.05). Muscle flap reconstruction is an effective means to create the 3D configuration of the philtrum. The biomechanical properties of muscles play a vital role in the morphological maintenance of the philtrum.