[Preventing and treating anterior commissure adhesion with mucosal flap: a study in canines and clinical cases].

Objective: To evaluate the effectiveness of mucosal flap combined with silicone keel for preventing and treating anterior commissure adhesion in canines and clinical cases. Methods: A prospective experiment was performed from November 2019 to June 2021. Twenty five canines were randomly divided into 5 groups(A, B, C, D, E). Group A, B, C, D received anterior commissure injury by CO2 laser, then separately treated with free mucosal flap-keel complex,intralaryngeal mucosal flap-keel complex, silicone keels and without treatment, group E didn't injure the vocal cord after intubation. The keel was removed after 2 weeks, the larynx was harvested after 4 weeks. The effectiveness of anterior commissure adhesion prevention was evaluated by manifestation under laryngoscope, standard vocal cord length and standard glottic area. A retrospective analysis was performed on sixteen patients with anterior commissure lesion, who underwent mucosal flap-keel technique in Huashan Hospital of Fudan University from January 2019 to January 2021 (10 cases with free mucosal flap-keel complex and 6 cases with intralaryngeal mucosal flap-keel complex). All the patients underwent evaluation of laryngeal function included manifestation under laryngoscope each month and voice analysis before and 3 month after surgery. SPSS 20.0 software was used for statistical analysis. Results: No surgery accident or complication happened in canines and patients. The standard vocal cord length and standard glottic area after 4 weeks in group B were significantly higher than those in group A, C, D (Hstandard vocal cord length=31.688, Hstandard glottic area=16.444, P<0.05). The standard vocal cord length and standard glottic area after 4 weeks in group A were also significantly higher than those in group C, D(Hstandard vocal cord length=20.936, Hstandard glottic area=11.786, P<0.05). The standard vocal cord length and standard glottic area after 4 weeks in group A, B, E were not significantly different to that before surgery(tA left standard vocal cord length=2.636, tA right standard vocal cord length=2.582, tB left standard vocal cord length=2.707, tB right standard vocal cord length=2.673, tE left standard vocal cord length=0.370, tE right standard vocal cord length=0.821, tA standard glottic area=2.731, tB standard glottic area=2.753, tE standard glottic area=-0.529, P>0.05). The standard vocal cord length and standard glottic area after 4 weeks in group C, D were significantly lower than those before surgery(tC left standard vocal cord length=16.137, tC right standard vocal cord length=13.984, tD left standard vocal cord length=11.903, tD right standard vocal cord length=14.587, tC standard glottic area=10.280, tD standard glottic area=22.974, P<0.05). During 6-18 months of follow-up in clinical patients, no one developed a glottic web. Three months after surgery, Jitter, Shimmer, noise to harmonic ratio(NHR), the maximum phonation time(MPT)in all patients were significantly different from preoperative(tintralaryngeal mucosal flap jitter=24.885, tintralaryngeal mucosal flap shimmer=22.643, tintralaryngeal mucosal flap NHR=6.202, tintralaryngeal mucosal flap MPT=-9.661, tfree mucosal flap jitter=25.459, tfree mucosal flap shimmer=18.683, tfree mucosal flap NHR=5.705, tfree mucosal flap MPT=-20.840, P<0.05). Conclusion: Mucosal flap combined with silicone keel is an effective technique for preventing and treating anterior commissure adhesion. The effect of pedicled intralaryngea lmucosal flap is better.