Roger L. Crumley

Laryngeal synkinesis revisited

First described in 1982, laryngeal synkinesis continues to play an important diagnostic and therapeutic role following recurrent laryngeal nerve (rln) injury. Vocal fold motion impairment (formerly called “vocal cord paralysis”), hyperadducted and hyperabducted vocal folds, and certain laryngeal spasmodic and tremor disorders are often best explained by synkinesis. A closer look at these mechanisms confirms that following rln injury, immobile vocal folds may be nearly normally functional (favorable), or spastic, hyperadducted, or hyperabducted (unfavorable). This has resulted in a functional classification of laryngeal synkinesis as follows: type I laryngeal synkinesis, with satisfactory voice and airway (vocal fold poorly mobile, or immobile); type II synkinesis, with spasmodic vocal folds and an unsatisfactory voice and/or airway; type III synkinesis, with hyperadducted vocal folds and airway compromise; and type IV synkinesis, with hyperabducted vocal folds, poor voice, and possible aspiration. This classification facilitates the understanding of laryngeal pathophysiology following RLN injuries and promotes a more scientific basis for management.

EVALUATION AND TREATMENT OF THE UNILATERAL PARALYZED VOCAL FOLD

The evaluation and treatment of patients with unilateral vocal fold paralysis have evolved as improvements in objective measurements of phonatory function and new modalities for treatment have developed. A thorough history, physical examination, subjective voice evaluation, objective voice analysis, and electromyography are used to make a diagnosis, determine the cause, and plan treatment. The goal of treatment of the patient with a unilateral vocal fold paralysis is to restore normal phonatory function without aspiration. Multiple modalities have developed to allow for restoration of nearly normal phonatory function, and these include voice therapy alone or in combination with injection medlalization, laryngoplastic phonosurgery, or laryngeal reinnervation. Otolaryngologists should be familiar with the incidence, cause, evaluation, and state-of-the-art treatment of unilateral vocal fold paralysis to optimize patient care and avoid suboptimal results often seen with antiquated or Inappropriate treatment.

Endoscopic Laser Medial Arytenoidectomy for Airway Management in Bilateral Laryngeal Paralysis

A review of our recent experience in patients with bilateral laryngeal paralysis is described. While we continue to use phrenic nerve transfers in patients with mobile arytenoids, patients with fixed arytenoids generally require some sort of vocal cord lateralization, either by arytenoidectomy and arytenoidopexy or by partial vocal cord resection. The endoscopic laser medial arytenoidectomy is a convenient and effective method for opening the posterior glottic airway. One arytenoid is reduced medially with the carbon dioxide laser. After about 3 months the opposite arytenoid can be treated similarly, if necessary. The procedure does not appear to affect arytenoid mobility, as the posterior commissure mucosa and underlying interarytenoid muscle are protected and hence unaffected by the procedure. Those patients with at least one mobile arytenoid cartilage are candidates for posterior cricoarytenoid muscle reinnervation. Although ansa cervicalis and phrenic nerve techniques have been described, the author has concentrated efforts on the phrenic nerve. This report describes the endoscopic laser medial arytenoidectomy procedure, while the phrenic nerve patients will be reported in a subsequent manuscript.

In Vivo Optical Coherence Tomography of the Human Larynx: Normative and Benign Pathology in 82 Patients

Objectives: Optical coherence tomography (OCT) is an emerging imaging modality that combines low‐coherence light with interferometry to produce cross‐sectional images of tissue with resolution about 10 μm. Patients undergoing surgical head and neck endoscopy were examined using a fiberoptic OCT imaging probe to study and characterize microstructural anatomy and features of the larynx and benign laryngeal pathology in vivo.

Unilateral Recurrent Laryngeal Nerve Paralysis

Recurrent laryngeal nerve (RLN) injury [without injury to the superior laryngeal nerve (SLN)] is the most common traumatic neurolaryngological lesion. The acute effects are immediate flaccidity of the ipsilateral vocal fold, loss of abduction and adduction, severe dysphonia to complete paralytic aphonia, and, frequently, aspiration of food and drink into the trachea. This article reviews the function of the four intrinsic laryngeal muscles innervated by the RLN and the individual effects of RLN transection on these muscles. Following acute denervation, the subsequent progression is either chronic denervation or nerve regeneration with laryngeal muscle reinnervation. Four possible scenarios are discussed here: complete reinnervation with synkinesis, partial reinnervation with synkinesis, mixed RLN injuries, and no reinnervation (complete paralysis). Electromyography may eventually assist the laryngologist in establishing these diagnoses, but currently not enough normative data exist for confirming laryngeal synkinesis unequivocally in every case. Treatment is generally by Teflon injection, medialization thyroplasty, arytenoid adduction procedures, or reinnervation by nerve transfer. The authors preference is nerve transfer, insofar as the quality of resultant phonatory voice, in his hands, has been superior to the other techniques.

Laryngeal synkinesis: its significance to the laryngologist.

Basic research and surgical cases have shown that the injured recurrent laryngeal nerve (RLN) may regenerate axons to the larynx that inappropriately innervate both vocal cord adductors and abductors. Innervation of vocal cord adductor muscles by those axons that depolarize during inspiration is particularly devastating to laryngeal function, since it produces medial vocal cord movement during inspiration. Many patients thought to have clinical bilateral vocal cord paralysis can be found to have synkinesis on at least one side. This will make the glottic airway smaller, particularly during inspiration, than would true paralysis of all the intrinsic laryngeal muscles. Patients with bilateral vocal cord paralysis should undergo laryngeal electromyography. If inspiratory innervation of the adductor muscles is present, simple reinnervation of the posterior cricoarytenoid muscle will fail. The adductor muscles also must be denervated by transection of the adductor division of the regenerated RLN.

Recommendations of the Neurolaryngology Study Group on laryngeal electromyography

The Neurolaryngology Study Group convened a multidisciplinary panel of experts in neuromuscular physiology, electromyography, physical medicine and rehabilitation, neurology, and laryngology to meet with interested members from the American Academy of Otolaryngology Head and Neck Surgery, the Neurolaryngology Subcommittee and the Neurolaryngology Study Group to address the use of laryngeal electromyography (LEMG) for electrodiagnosis of laryngeal disorders. The panel addressed the use of LEMG for: 1) diagnosis of vocal fold paresis, 2) best practice application of equipment and techniques for LEMG, 3) estimation of time of injury and prediction of recovery of neural injuries, 4) diagnosis of neuromuscular diseases of the laryngeal muscles, and, 5) differentiation between central nervous system and behaviorally based laryngeal disorders. The panel also addressed establishing standardized techniques and methods for future assessment of LEMG sensitivity, specificity and reliability for identification, assessment and prognosis of neurolaryngeal disorders. Previously an evidence-based review of the clinical utility of LEMG published in 2004 only found evidence supported that LEMG was possibly useful for guiding injections of botulinum toxin into the laryngeal muscles. An updated traditional/narrative literature review and expert opinions were used to direct discussion and format conclusions. In current clinical practice, LEMG is a qualitative and not a quantitative examination. Specific recommendations were made to standardize electrode types, muscles to be sampled, sampling techniques, and reporting requirements. Prospective studies are needed to determine the clinical utility of LEMG. Use of the standardized methods and reporting will support future studies correlating electro-diagnostic findings with voice and upper airway function.

Voice quality following laryngeal reinnervation by ansa hypoglossi transfer

Recurrent laryngeal nerve injury resulting in chronic unilateral vocal fold paralysis has been treated traditionally by implantation of various materials into the paralyzed vocal fold. Although the usage of these techniques, especially Teflon®‐glycerin paste injection, has been clinically established, they do not restore full functionality to the larynx (abduction, adduction, and vibratory synchronization of the vocal folds). Restoration of these functions, necessary for improved phonation, has been achieved at least on an experimental basis by reinnervation techniques previously described.

Determination of obstructive site in obstructive sleep apnea

Patients with obstructive sleep apnea syndrome (OSAS) may have airway obstruction at various levels, including the uvula‐soft palate complex, base of tongue, and/or possibly other sites. For patients with tongue base and/or laryngeal obstruction, uvulopalatopharyngoplasty (UPPP, ppp) will not alleviate the obstruction. Prior authors have proposed that the hyoid bone position as determined by cephalometric x‐rays can predict which patients have obstruction at a lower site than the soft palate.

Optical coherence tomography of laryngeal cancer.

Objectives: Optical coherence tomography (OCT) is a high‐resolution optical imaging technique that produces cross‐sectional images of living tissues using light in a manner similar to ultrasound. This prospective study evaluated the ability of OCT to identify the characteristics of laryngeal cancer and measure changes in the basement membrane, tissue microstructure, and the transition zone at the edge of tumors.