The use of injectable calcium hydroxylapatite in the surgically pretreated larynx with glottal insufficiency

The inside-out surgical anatomy of the paraglottic space a video-guided endoscopic dissection

Objectives

The paraglottic space is an essential anatomic compartment of the larynx. It is central to the spread of laryngeal cancer and to the choice of conservative laryngeal surgery and many phonosurgical procedures. Since its description, 60 years ago, the surgical anatomy of the paraglottic space was sparsely revisited. Amid the era of endoscopic and transoral microscopic functional surgery of the larynx, we provide here a long-awaited description of the inside-out anatomy of the paraglottic space.

Methodology

Using an endoscope equipped with a 3D camera, we dissected 10 hemilarynges from 5 fresh frozen cadavers from the inside out. Before dissection, we labeled the vessels through injecting them with colored latex. We explored the paraglottic space emphasizing its shape, boundaries, and contents. We documented our findings through endoscopic photography and video recordings.

Results

The paraglottic space is a spacious tetrahedral space located parallel not only to the glottic, but also to the subglottic and the supraglottic compartments of the laryngeal lumen. It has musculo-cartilaginous, musculo-fibrous, and mucosal boundaries. It is separated from the pyriform sinus only by mucosa. A cushion of fat surrounds its vascular and to a lesser extent its neural contents. Harbored intrinsic laryngeal muscles are endoscopically identifiable within the space, namely the thyroarytenoid, the lateral, and posterior cricoarytenoid muscles.

Conclusion

The endoscopic description of the paraglottic space partly fills the knowledge gap on the laryngeal anatomy from the inside out. It opens the door for novel diagnostic methods and for ultraconservative functional laryngeal interventions under endoscopic control.

Level of Evidence

N/A.

[Update on vocal fold augmentation]

Unilateral vocal fold palsy is a frequent cause of hoarseness. In the presence of glottis closure insufficiency, the effectiveness of conservative voice therapy is often limited and phonosurgery may be indicated. Injection laryngoplasty is effective for correction of insufficiency. Early intervention during the first 6 months after diagnosis is desired to avoid subsequent insufficient endogenous compensation. Particularly patients with glottic closure insufficiency ≤2 mm in stroboscopy may benefit from this procedure. With appropriate patient selection, duration of the effect exceeding 12 months has been described for hyaluronic acid, calcium hydroxylapatite, and autologous fat. Due to rare complications such as allergic swelling at the injection site, regular laryngoscopic monitoring and observation for two nights after injection are recommended. The voice must only be rested for a few hours.

The surgical treatment of unilateral vocal cord paralysis (UVCP): qualitative review analysis and meta-analysis study

PURPOSE

The objectives of this meta-analysis were to summarize the key surgical procedures for UVCP 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 focused on the comparison of voice outcome between different techniques for the UVCP treatment. Then, a quantitative analysis was carried out for papers published from 2013 onwards, reporting only adult patients with unilateral paralysis for each study, and each surgical technique was evaluated for its capability of achieving good functional outcomes in terms of GRBAS-I scale and maximum phonation time in seconds (MPT).

RESULTS

The search identified 1853 publications. A total of 159 articles were stratified and included according to our selection criteria. 21 out of 159 articles were selected for quantitative synthesis. For trans-oral techniques: the mean GRBAS-I scale were 2.33 before injection and 0.41 after injection. The mean MPT before injection were 4.78 and 12.50 after injection. For open techniques the mean GRBAS-I scale were 2.43 before surgery and 0.68 after surgery. For open technique, the mean MPT were 3.50 before surgery and 12.40 after surgery.

CONCLUSIONS

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