16. vocal cord paralysis and evaluation of hoarseness kk

Vocal cord paralysis and evaluation of hoarseness

1. Dr. Krishna Koirala Vocal cord paralysis and evaluation of Hoarseness 2020-04-15

2. Vocal cord paralysis Inability of one or both vocal cords to move Due to damage to the nerves going to the vocal cords or damage to the brain itself Common disorder, symptoms can range from mild to life threatening

3. Surgical anatomy Phonation initiated by area 4 in the Sylvian fissure of the cerebrum Peripheral vagal trunk – roots emerging from lower pons and upper medulla Passes through the jugular foramen beside the jugular vein, posterior to IX and anterior to the XI cranial nerves High in the neck it produces the superior laryngeal nerve Passes through the neck in the carotid sheath , gives recurrent laryngeal nerve in the neck

4. Recurrent laryngeal nerve Right: Arises from vagus at the level of right subclavian artery in neck & hooks around it Left: Arises from vagus in mediastinum at level of arch of aorta & loops around it

5. Nerve supply of larynx Motor supply of intrinsic muscles: Cricothyroid muscle: superior laryngeal nerve All other muscles: recurrent laryngeal nerve Sensory: Above vocal cord: superior laryngeal nerve Below vocal cord: recurrent laryngeal nerve

6. Classification Incomplete paralysis Recurrent laryngeal nerve palsy Left (75% ), Right (15%), B/L (10%) Abductor, Adductor Superior laryngeal nerve palsy Combined paralysis / complete paralysis

7. Etiology of vocal cord paralysis Trauma (35%) Surgical Trauma (20%) : Esophageal, Lung, Thyroid, Cardiac, Neck, Carotid Non-Surgical (15%) : RTA, Sports, Blunt Trauma Malignancies (25%) : Bronchial, Esophageal Thyroid, Nasopharyngeal, Neck nodes Idiopathic (15%) : Viral Neuritis Neurological (15%) : Multiple sclerosis, Amyotrophic Lateral sclerosis, Syringomyelia, parkinsonism, Head injury, Alcoholic and diabetic Neuropathy Inflammatory (5%) : Tuberculosis, Syphilis Miscellaneous (5%) : Rheumatoid arthritis, Hemolytic Anemia, Collagen Vascular diseases, left atrial enlargement (Ortner’s syndrome)

8. Right recurrent laryngeal nerve is more superficial Right nerve enters the thyroid at 45 angle but left lies in tracheo -esophageal groove Right nerve mostly passes superior to or b/w branches of inferior thyroid artery; left nerve mostly passes deep to inferior thyroid artery Why is right RLN commonly damaged in thyroid surgery?

9. Theories of vocal fold paralysis Semon’s Law (Rosenbach & Semon) : In all progressive organic lesions, abductor fibres of recurrent laryngeal nerve, which are phylogenetically newer , are more susceptible and thus first to be paralyzed compared to adductor fibres. Wagner’s and Grossman’s Theory Superior laryngeal nerve has an adductive effect through the cricothyroid Immobile vocal fold Para median position -Total pure unilateral RLN paralysis Lateral position - Combined paralysis of superior and rec. laryngeal nerve

10. Modern Thinking Final position of paralyses vocal cord is not static and results from Degree of muscle atrophy Degree of Re- enervation Extent of Synkinesis Why are the ABDUCTORS affected first ? Nerve fibres supplying the abductors are in periphery Muscle bulk for the abductors is less, so more susceptible to trauma Phylogenetically, larynx’s main function is protection, so functions of the adductors are maintained

11. Clinical Features Lesion above pharyngeal branch Inability to elevate soft palate, nasal intonation & nasal regurgitation Gag reflex reduced due to palsy of internal branch of superior laryngeal nerve Hoarseness due to palsy of intrinsic muscles of larynx

12. Superior laryngeal nerve palsy Disability of voice seen in singers only Voice is weak & breathy Inability to raise pitch of voice (loss of timbre) Cough & choking due to aspiration caused by laryngeal anesthesia (especially in B/L palsy) Vocal cord bowed & floppy with phonatory gap. Anterior commissure pushed to healthy side & posterior commissure to paralyzed side (Askew position of glottis)

13. Unilateral combined palsy Bilateral combined palsy I/L cord in cadaveric position  hoarseness B/L cords in cadaveric position  aphonia Partial anesthesia of larynx  a spiration Total anesthesia of larynx  a spiration + bronchopneumonia

14. Specific Investigations Analysis of vocal cord movement Rigid 70 video - telescopy Fibreoptic video-laryngoscopy Stroboscopy: Intermittent flashlight focussed on vocal cords during phonation Frequency of light made 2 m sec slower to cord frequency Produces slow motion movement of vocal cords for better analysis of cord movement

15. Vocal cord paralysis Cricoarytenoid joint fixation Floppy, vocal cords with bowing Arytenoids falls antero-medially Vocal cord at a higher level Tilting of larynx  paralysed side Flickering of cord on phonation Shallow pyriform fossa Cord fixed in specific position Arytenoids mobile during MLS Absent In position Same level Absent Absent Normal Any position Arytenoids fixed

16. B/L adductor Palsy B/L abductor Palsy

17. Radiology: Chest X-ray PA view Barium swallow AP & lateral oblique view High resolution CT scan with contrast from skull base to mid thorax: gold standard M.R.I. : ideal for skull base lesions Thyroid scan

18. Pan - Endoscopy Performed for vocal cord palsy associated with metastatic lymph nodes Consists of: Nasopharyngoscopy Micro-laryngoscopy Bronchoscopy & bronchial washings Hypopharyngoscopy Esophagoscopy

19. Biopsy for suspected malignancy FNAC from enlarged lymph nodes Punch biopsy from visible growth Blind biopsy from (if metastatic node present) Fossa of Rosenmuller Retromolar trigone Base of tongue Pyriform fossa Laryngeal ventricles Bronchial carina

20. Treatment for phonatory gap in U/L palsy Speech therapy : for 2-12 months (usual treatment) Vocal cord injection : with Teflon / fat / collagen Medialization Thyroplasty (Isshiki type I) Arytenoid adduction : for posterior approximation Arytenoidopexy : medial rotation + fixation Laryngeal re-innervation Combination of above

21. Isshiki’s Thyroplasty Type 1 (medial displacement) Type 2 (lateral displacement) Type 3 (shortening or relaxation) Type 4 (lengthening or tensioning) Thyroplasty is reversible, does not invade vocal folds nor alter their mass or stiffness unlike vocal fold injection

22. Neuromuscular pedicle of superior belly of omohyoid (or sternohyoid) + ansa hypoglossi nerve transferred into thyro-arytenoid for vocal fold medialization Neural anastomosis of ansa hypoglossi nerve directly to recurrent laryngeal nerve (Crumley) Laryngeal re-innervation

23. Neuromuscular pedicle Ansa RLN Anastomosis

24. Treatment of stridor in B/L abductor paralysis Tracheostomy: temporary / permanent Vocal cord lateralization: endoscopic, external (King) Lateralization Thyroplasty (Isshiki type II) Endoscopic vocal cordotomy: knife, cautery, laser Vocal cordectomy: endoscopic Arytenoidectomy: endoscopic, external (Woodman) Laryngeal re-innervation: ansa hypoglossi-omohyoid pedicle transfer into posterior crico-arytenoid

25. Treatment for bilateral adductor paralysis causing chronic aspiration Endolaryngeal stenting (solid & vented) Epiglottic flap closure Epiglottopexy to posterior pharyngeal wall Epiglottic tube laryngoplasty Glottic closure Double cuff tracheostomy Tracheo- esophageal diversion Laryngo-tracheal separation Narrow field laryngectomy

26. Evaluation of Hoarseness (dysphonia)

27. Causes of Hoarseness Congenital : laryngomalacia, web, hemangioma Inflammatory: bacterial, viral, TB, allergic, GERD Traumatic : accidental, foreign body, intubation Neoplastic : papilloma, malignancy Non neoplastic : Vocal nodule, vocal polyp, Reinke’s edema Neurological: Parkinsonism, multiple sclerosis, cerebro-vascular accident, bulbar palsy , myasthenia gravis Endocrine : Hypothyroidism, inter-sex, pregnancy Functional : Puberphonia, plica ventricularis, malingering

28. History Taking

29. History Taking

30. Physical Examination

31. Manual compression test Improvement in voice : Thyroplasty (anterior medialization procedure) No improvement in voice : Arytenoid adduction (posterior medialization procedure)

32. Routine Investigations Fiber-optic laryngoscopy Micro laryngoscopy : crico-arytenoid joint mobility Contrast CT scan (skull base to diaphragm): best X-ray chest: for hemoptysis Ba swallow: for dysphagia Thyroid scan: for thyroid enlargement Pan endoscopy: in presence of metastatic neck nodes