Short-Term Evaluation of the APrevent® VOIS Implant: Outcomes at 7 Weeks Post-Implantation

Introduction: Type I medialization thyroplasty (MT) is one of the standard procedures in patients having permanent unilateral vocal fold paralysis (UVFP) with insufficient glottal closure. The objective of this study was to evaluate the clinical outcome in patients with UVFP 7 weeks post-implantation using the novel APrevent® VOIS (VOIS) implant with its adjustable balloon.

The VOIS implant was applied in 32 patients with UVFP during MT. The following parameters were assessed pre- and 7 weeks post-implantation: glottal closure according to Södersten and Lindestad classification (videolaryngostroboscopy), perceptual voice assessment (GRBAS scores), acoustic voice parameters (jitter %, shimmer Db, and harmonic to noise ratio [HNR in dB]), maximum phonation time (MPT in s), voice range profile (VRP), as well as the subjective voice rating of patients (voice handicap index [VHI-30]).

Significant improvement in glottal closure was achieved in 28 patients (87.5%) 7 weeks after MT with VOIS implant. Adjustment via emptying and refilling of the incorporated balloon of the implant was necessary in 5 patients to further improve or restore the glottal closure. The mean GRBAS scores improved from preoperatively G_pre = 2.6 ± 0.5, R_pre = 2.4 ± 0.7, B_pre = 2.3 ± 0.8, A_pre = 1.9 ± 0.8, S_pre = 1.7 ± 0.8 to postoperatively G_post = 0.7 ± 0.7, R_post = 0.8 ± 0.8, B_post = 0.3 ± 0.6, A_post = 0.3 ± 0.5, S_post = 0.3 ± 0.4. The mean MPT improved from 4.4 ± 2.6 s preoperatively to 9.0 ± 5.8 s postoperatively. All acoustic voice parameters showed significant improvement as well. The mean jitter % reduced from preoperative 2.80 ± 8.89% to postoperative 0.70 ± 0.73, the mean shimmer dB from 1.18 ± 0.48 dB to 0.70 ± 0.73 dB, whereas the HNR gained from 12.19 ± 6.96 dB to 18.36 ± 4.87 dB, respectively. Within the VRP, the intensity level (I-level_shouting [dB]) and fundamental frequency (F0_shouting [Hz]) in the shouting voice showed improvement as well. The I-level_shouting improved from 69.4 ± 12.7 dB preoperatively to 72.5 ± 13.3 dB postoperatively and the F0_shouting from 214.2 ± 64.0 to 230.2 ± 62.6 Hz, respectively. Post-VOIS implantation, the mean VHI-30 score significantly reduced from preoperative 72.1 ± 20.5 to postoperative 19.2 ± 18.5. No complications were observed both intra- and postoperatively. All described improvements reached statistical significance with p < 0.05.

The novel VOIS implant can be applied safely in patients with UVFP. Patients can further benefit from the intra- and postoperative adjustment, especially that of the posterior glottal closure using the custom-fitting option by re-filling the balloon of the implant. To better evaluate the sustainability of the VOIS implant in terms of safety and effectiveness for patients with UFVP, it is crucial to conduct further analysis of long-term outcomes post-implantation in future studies.