Fig. 7.1
Trans-thyroid cartilage approach
Fig. 7.2
Trans-thyroid cartilage approach
Transcricothyroid Approach [12] (Fig. 7.3): the patient was asked to assume a sitting position with the neck extended. A 26-gauge needle bent approximately 2 cm from its tip was introduced through the cricothyroid laterally off the midline directly into the paraglottic space to avoid intraluminal penetration of the trachea. The needle was angled superomedially just under the inferior border of the thyroid cartilage; while watching on the video monitor, the material is injected until the adequate medialization of the vocal fold.
Fig. 7.3
Transcricothyroid approach
Trans-thyrohyoid Approach [13] (Fig. 7.4): a 25-gauge needle is introduced and led down till it reaches the laryngeal lumen through the epiglottis petiolus. The needle is perfectly now visible through the fiberscope, and it is led in the vocal cord, more precisely than other transcutaneous techniques. Moreover it offers the same accuracy as laryngoplasty through fiberoptic endoscopy, but the procedure is easier and faster. A similar approach using a curved needle is recently described [14].
Fig. 7.4
Transthyrohyoid approach
Moreover it’s possible to perform immediately a voice examination and a laryngostroboscopy.
7.3 Materials for Injection
Today many materials are available for injection laryngoplasties; they can be divided in:
Short-lasting materials: GelfoamTM, SurgifoamTM, hyaluronic acid, and Radiesse Voice GelTM
Long-lasting materials: autologous fat, calcium hydroxylapatite (RadiesseTM), and mesenchymal acellular materials (CymetraTM, ZyplastTM, Cosmoplast/CosmodermTM) [15–17]
Non-reabsorbable materials: polydimethylsiloxane (Vox-ImplantsTM)
Only short- and long-lasting materials are commonly used in transcutaneous procedures.
Many studies demonstrated good results in rehabilitation of glottic incompetence with injection laryngoplasty using Gelfoam, autologous fat [18], or collagen [19]. Damrose [20] treated acute vocal fold paralysis with injection of bovine collagen via percutaneous laryngoplasty with a significant improvement in voice function. Rosen et al. [21] used RadiesseTM, a combination of calcium hydroxylapatite microspheres suspended in carboxymethylcellulose carrier gel, to treat patients with unilateral focal fold paralysis or glottal incompetence with mobile vocal folds. He showed that this material can last up to 12 months with good results in improvement of voice and objective voice measures.
7.4 Indications for Transcutaneous Injection Laryngoplasty
The transcutaneous injection laryngoplasty allows the treatment of vocal cord paralyses, thyroarytenoid muscle atrophy (age-related dysphonia), spasmodic dysphonia [10], vocal fold granuloma [22, 23], Reinke edema [24], and androphonia [25].
Transcutaneous laryngoplasty with local anesthesia can be performed in all patients with low performance status and when the general anesthesia is hazardous (i.e., treatment of hypophonia in patients with Parkinson disease [26, 27]). The same procedure can be carried out under conscious sedation.
No complications after the procedure are reported in patients on anticoagulant therapy [28]: bleeding and hematoma formation are really infrequent due to the use of thin needles and the low vascularization of injection points. However antiplatelet drugs and anticoagulants should be stopped before the procedure and replaced with heparin whenever is possible.
Choi et al. [29] recently demonstrated that younger patients with a smaller posterior glottic gap on phonation can be expected to have a more favorable outcome following transcutaneous injection laryngoplasty for correction of glottic insufficiency.
Previous approaches to unilateral vocal fold paralysis are to proceed with medialization after several months when spontaneous recovery was ruled out [30]. Recent evidence, however, suggests that early intervention reduces the need for transcervical reconstruction [31, 32].
The development of this minimally invasive procedure and short-lasting materials was allowed to treat potentially reversible laryngeal palsy easily and early. Anderson and Mirza [33] demonstrated the efficacy of immediate bedside percutaneous, trans-thyroidal injection of a bioabsorbable material to decrease the risk of aspiration resulting from acute vocal fold immobility. Bhattacharya et al. [34] analyzed a group of patients with new-onset unilateral vocal fold paralysis after thoracic surgery. Early medialization (within 4 days from thoracic procedure) decreased the pneumonia rate, the requirement for postoperative bronchoscopies, and the length of stay. Similarly Grant et al. [28] obtained an improvement of swallowing and voice functions in all the patients that underwent augmentation shortly following thoracic surgery, with a very low rate of complications.
7.5 Advantages and Disadvantages
The transcutaneous injection laryngoplasty offers many advantages compared with traditional techniques (injection laryngoplasty by means of microlaryngoscopy, thyroplasty, etc.). It’s an outpatient procedure performed under local anesthesia, without skin incision, and well tolerated by the patient. It can be carried out early after a vocal cord paralysis ensuring a restoration of the voice and swallowing functions.
The debate about the better injection laryngoplasty technique (transcutaneous injection or transoral approach under total anesthesia) is still open.
Surely transcutaneous laryngoplasty is less expensive than any other technique in the treatment of unilateral vocal fold paralysis. Since it avoids general anesthesia, a saving of 40 million dollars per year is estimated in the USA [35].
Mathison in 2009 [36] compared clinical outcomes and complication rates in patients undergoing injection laryngoplasty under local versus general anesthesia. He found that both injection laryngectomies offer comparable results in quality of life. Although having the benefit of avoiding general anesthesia, transcutaneous injection laryngoplasty has a slightly higher complication rate due to lack of direct visualization of the needle tip during any of the percutaneous injection laryngoplasty approaches and poor patient tolerance to the procedure. The most frequent complications include hematoma of the vocal fold, vasovagal attack, wrong injection site (i.e., in superficial layer of lamina propria) and more rapid reabsorption of the material if it was injected in the medial part of the thyroarytenoid muscle.
Moreover the transoral approach (in microlaryngoscopy) is recommended when long-lasting or non-reabsorbable materials are used. In this type of approach it’s necessary to inject the substance in the correct position to prevent its migration and granulomatous reactions.
References
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