• laryngeal paralysis
• injection laryngoplasty
• thyroplasty
• meta-analysis
• systematic review

Background: The unilateral paralysis of the vocal cords (UVFP) defined as the complete immobility of a vocal fold is one of the main causes of dysphonia which causes a considerable effect on the quality of life of affected patients.
A large number of causes have been attributed to its appearance and its etiology shows changes in trends from place to place and over time. It is important to arrive to a correct diagnosis to plan its management and determine the prognosis of each patient.
Today we have different approaches and more or less invasive surgical techniques to restore functional intonation and improve glotal insufficiency.
From these observations, we examine the various surgical treatments for unilateral laryngeal paralysis in the last 5 years in order to provide a comprehensive overview of the latest advances in the treatment of this disease and to compare the benefits of various surgical treatments and their impact on language improvement. through the voice outcome indicators (VOI).

Object : Surgical treatment of the paralysis of the vocal cords should be appropriate and adapted to the clinical conditions and needs of each patient. There are different surgical techniques, more or less invasive, definitive or temporary and different materials with different duration and characteristics to obtain the medialization of the affected vocal cord. The objectives of this systematic review and meta-analysis were to summarize the key surgical management for the unilateral paralysis of the vocal cords and to evaluate which of these is associated with better results in terms of vocal improvement.

Methods: A systematic review of the literature was conducted in search of articles mentioning the following terms including their various combinations to maximize yield: laryngeal paralysis, zyderm, radiesse, restylane, calcium hydroxylapatite, fat , autologous fat, hyaluroyc acid, bovine collagen, human collagen, hylaform , perlane, teflon, reinnervation.
Then, a quantitative analysis was carried on for paper published after 2013 onward, reporting only adult patients with unilateral paralysis for each study, declaring each surgical technique was evaluated for its capacity in achieving good functional outcomes in term of GRBAS and MPT. Results: The search identified 1853 publications, of which 1445 published after 2013 , with a final results of a total of 159 articles stratified and included by our selection criteria. 21 out of 159 articles were selected for quantitative synthesis. 9 out of 21 studies had a quality score of ≥ 6 (good), 8 presented a score between 4 and 5 (fair). Both the transoral and the open definitive techniques lead to a significant improvement of both GRBAS and MPT.
For trans-oral techniques: the mean (SD) GRBS were 1.8285(1.1134) before injection and 0.3795(0.3678) after injection. The mean (SD) MPT before injection were 2,38(2,54) and 6.2490(6.7352) after injection.
For open techniques the mean (SD) GRBS were 2,560(0,288) before surgery and 24,20 (32,46)after surgery. For open technique the mean (SD) MPT were 0,700(1,565) before surgery and 0,550(0,432) after surgery.

Conclusions:
In conclusion both the two types of techniques lead to a significant improvement in terms of vocal outcomes emphasizing that from the examined literature emerges an indication to perform an early injection because this could reduce the possible need for a more invasive intervention of permanent medialization in the future .