Vocal Cord Augmentation/Injection Laryngoplasty




Keywords

Vocal Cord, Augmentation, Paralysis, Laryngoplasty, Teflon, Granuloma

 




Introduction


Injection laryngoplasty is performed for treatment of vocal cord paralysis, which may have a variety of causes ( Box 46.1 ). Imaging during a Valsalva maneuver demonstrates the mechanical and physiologic barriers that patients with unilateral vocal cord paralysis endure ( Fig. 46.1 ). Vocal cord augmentation procedures attempt to overcome these barriers by medializing the affected vocal fold, thus allowing for better phonation and alleviating risk for aspiration. Temporary injectable materials, which last a few weeks to a few months, include hyaluronic acid, collagen, and Gelfoam. Long-lasting and permanent agents include calcium hydroxyapatite paste, autologous fat, and polytetrafluoroethylene past (Teflon). These injected materials can be incidentally encountered on imaging obtained for other reasons, such as cancer surveillance. Alternatively, injection laryngoplasty is subject to certain complications that may warrant diagnostic imaging evaluation. Laryngoplasty evolution and potential complications, including Teflon granuloma, will be the focus of the following discussion ( Fig. 46.2 ).



Box 46.1

Most Common Causes of Vocal Cord Paralysis





  • Surgery




    • Nonthyroid (i.e., anterior cervical spine, carotid endarterectomy, neck dissection, and cardiac)



    • Thyroid/parathyroid resection




  • Malignancy




    • Lung carcinoma



    • Thyroid carcinoma



    • Esophageal carcinoma




  • Idiopathic



  • Other




    • Trauma



    • Intubation



    • Neurologic



    • Infectious (i.e., tuberculosis)



    • Congenital






Figure 46.1


Unilateral vocal cord paralysis without and with Valsalva. Coronal computed tomography (CT) images of the neck (A and B) demonstrates right thyroarytenoid muscle volume loss ( red arrow in A) and indirect signs of vocal cord paralysis that include dilatation of the right laryngeal ventricle ( yellow arrow in A), as well as dilatation of the right pyriform sinus and medialization of the right aryepiglottic fold ( yellow arrows in B). Axial CT image of the neck at the level of the vocal fold in neutral position (C) demonstrates right cricoarytenoid muscle volume loss ( red arrow ) and right laryngeal ventricle dilatation termed the “sail sign” ( yellow arrow ) consistent with right vocal cord paralysis. Axial CT image of the neck at the level of the vocal fold during Valsalva (D) demonstrates fixed, paralyzed position of the right vocal fold with medial bowing of the normal functioning left vocal fold ( orange arrow ) attempting to appose the nonfunctional contralateral right vocal fold. Right-sided vocal cord augmentation would facilitate proper glottis apposition to improve phonation and minimize risk for aspiration.

(Courtesy Samir Noujaim, MD, William Beaumont Hospital, Royal Oak, MI.)



Figure 46.2


Evolution of laryngoplasty. (Left) Left-sided vocal cord paralysis with atrophy of left thyroarytenoid muscle. (Center) Various materials may be injected to achieve medialization of the vocal fold. (Upper Right) Temporary materials typically lose volume over time and resume previous morphology. (Lower Right) Permanent material, such as Teflon, may develop a foreign body reaction termed Teflon granuloma.




Temporal Evolution: Overview


Calcium hydroxyapatite initially displays calcific attenuation on computed tomography (CT) but gradually resorbs over 12 to 18 months, with decreasing bulk and attenuation ( Fig. 46.3 ). Furthermore, calcium hydroxyapatite can stimulate local fibroblast activity and macrophage accumulation, which leads to focal hypermetabolism on fluorodeoxyglucose (FDG)–positron emission tomography (PET) ( Fig. 46.4 ). Although it can last for years, autologous fat also shrinks over time. Therefore fat is often generously or overinjected for vocal cord medialization ( Fig. 46.5 ). However, excess injection of laryngoplasty agents can lead to laryngocele formation with airway obstruction and dysphonia ( Fig. 46.6 ). Teflon is notorious for inciting a foreign body giant cell reaction that leads to granuloma formation, which can cause airway obstruction and dysphonia as well. On CT, a Teflon granuloma typically appears as a concentric soft tissue mass surrounding the hyperattenuating Teflon ( Fig. 46.7 ). The granuloma can also be hypermetabolic on FDG-PET ( Fig. 46.8 ).


Jun 26, 2019 | Posted by in NEUROLOGICAL IMAGING | Comments Off on Vocal Cord Augmentation/Injection Laryngoplasty
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