RESUMO
OBJECTIVES: Topical lidocaine remains the mainstay for anesthesia in transcutaneous vocal fold injection (VFI). While using topical lidocaine, laryngologists sometimes encounter uncontrolled reflexes or poor compliance. Superior laryngeal nerve block (SLNB) provides deep and rapid anesthesia on the larynx above the vocal folds and abolishes the glottic closure reflex. Herein, we present a pilot study to evaluate the feasibility and safety of SLNB for transcutaneous VFI and explored its usefulness. METHODS: Fifty-nine patients were prospectively anesthetized with SLNB during transcutaneous VFI for unilateral vocal fold paralysis. In the SLNB group, 0.5 to 1 mL of 2% lidocaine was infiltrated on bilateral SLNs through the thyrohyoid membrane. As the control group, we included previous 47 patients who underwent VFI with topical lidocaine. In the control group, 10% lidocaine spray was applied to the laryngopharyngeal mucosa. Demographic data, laryngeal exposure, patient compliance, procedural interruption, and complications were investigated. Patient compliance was evaluated based on the frequency of cough and swallowing during VFI procedures. RESULTS: SLNB enabled endoscopic contact on the epiglottis and pharyngeal wall without gag reflex and provided good exposure of the procedure field on the vocal folds. In the SLNB group, the laryngeal exposure is significantly better than in the control (P = 0.005). The frequency of cough and swallowing was significantly lower in the SLNB group than in the control (P < 0.001). The number of procedural interruptions was lower in the SLNB group than in the control (P < 0.001). There was no acute or delayed complication related to SLNB such as bleeding, hematoma, delayed sensory/swallowing problems, or unscheduled hospital visits. CONCLUSIONS: SLNB might be safe and effective for anesthesia in transcutaneous VFI. SLNB could be a good anesthetic option for patients with poor compliance despite the sufficient application of topical lidocaine.
RESUMO
OBJECTIVES: Vocal fold injection (VFI) via the cricothyroid (CT) membrane is used to treat various diseases affecting the vocal folds. The technical challenges of this technique are mainly related to the invisibility of the needle. Real-time light-guided VFI (RL-VFI) was recently developed for injection under simultaneous light guidance in the CT approach. Herein, we present the first clinical trial of RL-VFI, in which we investigated the feasibility and safety of this new technique in unilateral vocal fold paralysis (VFP). METHODS: This prospective pilot study enrolled 40 patients, who were treated with RL-VFI for unilateral VFP between September 2020 and August 2021. Adverse events were monitored during the procedure and for 4 weeks postoperatively. The Voice Handicap Index-10, the GRBAS (grade, roughness, breathiness, asthenia, and strain) scale, aerodynamic studies, and acoustic analyses were evaluated to compare the voice improvement after 4 weeks with the baseline values. RESULTS: The needle tip was intuitively identified by the red light. The mean procedure time was 95.6±40.6 seconds for the initial injection, while the additional injection required 79.2±70.5 seconds. The injection was performed under light guidance without additional manipulation after the needle reached the intended point. No acute or delayed adverse events were reported. Among the 40 patients, 36 completed voice analyses after 4 weeks. Subjective and objective voice parameters, including the Voice Handicap Index-10, GRBAS scale, maximum phonation time, mean expiratory airflow, fundamental frequency, jitter, shimmer, and noise-to-harmonics ratio improved significantly after RL-VFI (P<0.05), while the expiratory volume was maintained. CONCLUSION: RL-VFI is feasible and safe for treating patients with unilateral VFP. This technique is anticipated to improve the precision and safety of the CT approach in the treatment of unilateral VFP. This study provides a rationale for further structured clinical studies.
RESUMO
OBJECTIVES: The transcutaneous approach is a good option for office-based vocal fold injection (VFI). However, precise localization requires extensive experience because the needle tip is invisible in small and complex laryngeal spaces. Recently, real-time light-guided VFI (RL-VFI) was proposed as a new technique that allows simultaneous injection under precise needle localization by light guidance. Herein, we aimed to verify the feasibility of RL-VFI in an in vivo canine model and explored its clinical usefulness. METHODS: The device for RL-VFI comprised a light source (light-emitting diode modules [10 W] of red color [650 nm]) and injectors (1.5 inches, 23 gauge). An adult male beagle was used for the experiment. After tracheostomy, a rigid laryngoscope was inserted and suspended to expose the larynx. A flexible naso-laryngoscopy system was used to visualize the vocal folds. RESULTS: RL-VFI was performed using various transcutaneous approaches, including the cricothyroid, transthyroid, and transhyoid approaches. Light guidance helped identify the path of the needle and prevent inadvertent penetration. The location of the needle tip was accurately indicated by the light. The illuminated needle could be easily placed at the intended points in the vocal fold with real-time visual-motor feedback. Hyaluronic acid could be simultaneously injected lateral to the vocal process under light guidance without manipulation of the device. CONCLUSION: RL-VFI was found to be safe and feasible in an in vivo canine model, providing precise localization and visualmotor feedback. The clinical application of RL-VFI is expected to improve the safety and precision of VFI.
