Vocal cord palsy & evaluation of hoarseness Dr. Vishal Sharma

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

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

Development of arterial arches

Final position of B/L RLN

Superior laryngeal nerve Arises from inferior ganglion of vagus Descends behind internal carotid artery at level of greater cornu of hyoid bone divides into external & internal branches External motor branch: to cricothyroid muscle Internal sensory branch: pierces thyrohyoid membrane to enter larynx

Dual innervation of inter-arytenoid muscles

Classification A. Incomplete paralysis 1. Recurrent laryngeal nerve palsy a. Left (75% ), Right (15%), B/L (10%) b. Abductor, Adductor 2. Superior laryngeal nerve palsy B. Combined paralysis / complete paralysis

Causes of laryngeal paralysis Supra-nuclear Nuclear: nucleus ambiguus High vagal lesions: combined palsy Low vagal lesions: recurrent laryngeal nerve palsy Systemic causes Idiopathic

Causes of combined paralysis Intracranial Neck Tumors of posterior fossa Penetrating injury Basal meningitis (TB) Parapharyngeal tumors Skull base Metastatic neck nodes Fractures Lymphoma Nasopharyngeal cancer Thyroid surgery Glomus tumour

Etiology of recurrent laryngeal nerve palsy

Malignancy (25%): lung (>50%), thyroid, esophageal, Malignancy (25%): lung (>50%), thyroid, esophageal, nasopharyngeal, metastatic neck node Surgical trauma (20%): during surgeries of lung, heart, thyroid, esophagus, mediastinum Inflammatory (13%): tuberculosis, syphilis Idiopathic (13%): viral neuritis Non-surgical trauma (11%): accidental neck trauma, left atrial enlargement (Ortner), aortic aneurysm Neurological (7%): CVA, head injury, Parkinsonism, multiple sclerosis, alcoholic / diabetic neuropathy Others (11%): rheumatoid arthritis, haemolytic anemia

Causes of left RLN palsy (75%) Neck  Accidental trauma  Thyroid disease  Thyroid surgery  Ca esophagus  Lymphadenopathy Mediastinum  Bronchogenic ca  Ca esophagus  Aortic aneurysm  Lymphadenopathy  Enlarged left atrium  Intra-thoracic surgery

Causes of right RLN palsy (15%) Neck trauma Thyroid disease Thyroid surgery Ca cervical esophagus Cervical lymphadenopathy Aneurysm of subclavian artery Ca apex right lung TB of cervical pleura

Causes of B/L RLN palsy (10%) Thyroid surgery Ca thyroid Cancer cervical esophagus Cervical lymphadenopathy

Congenital vocal cord paralysis Unilateral: birth trauma, congenital anomaly of great vessel or heart Bilateral:  Hydrocephalus  Meningocoele  Arnold-Chiari malformation  Cerebral agenesis  Intra-cerebral hemorrhage  Nucleus ambiguus agenesis

Thyroid surgery Joll’s sterno-thyro-laryngeal triangle for S.L.N.: Lateral = superior thyroid vessels & upper thyroid pole; superior = attachment of strap muscles to thyroid cartilage; medially = midline Beahr’s triangle for recurrent laryngeal nerve: Lateral = common carotid artery; superior = inferior thyroid artery; medial = tracheo-esophageal groove + recurrent laryngeal nerve

Joll’s triangle for SLN

Beahr’s triangle for RLN

Why right RLN commonly damaged in thyroid surgery? Right recurrent laryngeal nerve more superficial Right nerves enters thyroid at 450 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

Paralysis of both RLN & SLN Paralysis of adductors Position of vocal cord Distance from centre Healthy Diseased Median Midline Phonation RLN paralysis Paramedian 1.5 mm Strong whisper Intermediate (Cadaveric) 3.5 mm (neutral position) Paralysis of both RLN & SLN Gentle abduction 7 mm Quiet respiration Paralysis of adductors Full abduction 9.5 mm Deep inspiration --

Position of vocal cords

Semon’s Law Rosenbach (1880) & Semon (1881) “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.”

1st stage: only abductor fibres damaged; vocal folds approximate in midline; adduction still possible (paramedian position) 2nd stage: contracture of adductors; vocal folds immobilized in median position 3rd stage: adductors become paralyzed; vocal fold assumes cadaveric position

Why abductors affected first ? Nerve fibres supplying abductors are in periphery of recurrent laryngeal nerve Muscle bulk for the abductors is less, more susceptible Phylogenetically, larynx’s main function is protection, so adductor functions are maintained

Wagner & Grossman Theory In isolated paralysis of recurrent laryngeal nerve, cricothyroid muscle (which receives innervation from superior laryngeal nerve) keeps vocal cord in paramedian position due to adductor function In superior laryngeal nerve palsy, cord lies in intermediate (cadaveric) position

Modern theory Final position of paralyses vocal cord is not static & is decided by: Degree of paralyzed muscle atrophy & fibrosis Degree of re-innervation following injury Extent of synkinesis (mass movement) of all intrinsic muscles Fibrosis & ankylosis of crico-arytenoid joint

Intermediate position of vocal cords in RLN palsy ? Retrograde atrophy of vagus nerve occurs up to nucleus ambiguus Stretching of RLN by enlarged intra-thoracic lesions pulls vagus nerve down from skull base, injuring superior laryngeal nerve

Cricoarytenoid joint fixation 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 Fixed in specific position Arytenoids can be moved Absent In position Same level Normal Any position Arytenoids fixed

Clinical Features

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

Asymptomatic (1/3rd unilateral paralysis) Faint whisper Functional adductor paralysis Forced whisper Organic adductor paralysis Voice tires with use Unilateral abductor paralysis Stridor & aspiration Bilateral abductor paralysis

U/L S.L.N. palsy B/L S.L.N. palsy Disability in professional voice user only Voice weak, breathy, inability to raise pitch Anterior commissural tilt to healthy side Short & flabby vocal fold Flapping cord during respiration Professional voice compromised Absence of anterior commissural tilt Cough & choking due to aspiration

U/L combined palsy B/L combined palsy Cord in cadaveric position  hoarseness Glottic incompetence  ineffective cough Partial anesthesia of larynx  aspiration B/L cords in cadaveric position  aphonia Total anesthesia of larynx  aspiration + bronchopneumonia

Specific Investigations

Voice assessment 1. Magnetic tape recording: for self assessment 2. Performance assessment by examiner: maximum phonation time & range of speech frequencies 3. Phonetogram: plot of pitch vs. intensity of voice 4. Aerodynamic analysis: phonatory airflow rate, subglottic pressure & laryngeal resistance

Phonetogram

Aerodynamic analysis

5. Fourier’s Spectral analysis (Spectrogram) Fundamental frequency: lowest speech frequency Shimmer: average cycle to cycle difference in amplitude of sound Jitter: average cycle to cycle difference in duration of glottal cycle In hoarseness there is increased shimmers & jitters

Spectrogram

Shimmer & Jitter

Analysis of cord movement 1. Rigid 700 video-telescopy ↓LA 2. Fibreoptic video-laryngoscopy 3. Stroboscopy: Intermittent flash light focussed on vocal cords during phonation. Frequency of light made 2 msec slower to cord frequency. Produces slow motion movement of vocal cords for better analysis of cord movement

Video-stroboscopy

4. Electro-glottography: 2 electrodes placed on both sides of thyroid cartilage & current passed b/w them. Recorded waveform shows impedance across larynx & is highest during contact b/w vocal cords. Records closing phase of glottal cycle. 5. Photo-glottography: fibreoptic light source passes light via glottis & is received by photo-sensor on neck skin. Light received  glottic chink. Records opening phase of glottal cycle.

Electroglottography

Photoglottography

Radiological Submento-vertical skull base view X-ray neck AP & lateral view 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

Endoscopy 1. Rigid 700 Telescopy ↓ LA 2. Fibreoptic Laryngoscopy ↓ LA 3. Pan-endoscopy ↓ GA (for metastatic node): a. Nasopharyngoscopy b. Micro-laryngoscopy: probe test on arytenoids c. Bronchoscopy & bronchial washings d. Hypopharyngoscopy e. Oesophagoscopy

Fibre-optic laryngoscopy paralyzed vocal fold is foreshortened, lateralized & flaccid

B/L abductor palsy Inspiration Expiration

Biopsy for suspected malignancy 1. F.N.A.B. from enlarged lymph nodes 2. Punch biopsy from visible growth 3. Blind biopsy from (if metastatic node present): Fossa of Rosenmuller Base of tongue Pyriform fossa Laryngeal ventricles Bronchial carina

Respiratory function test 1. Conventional spirometry 2. Flow-Volume Loop analysis Variable extra-thoracic obstruction: ↓ed inspiratory flow Intra-thoracic obstruction: ↓ed expiratory flow Fixed obstruction: ↓ed inspiratory + expiratory flow

Flow volume loop analysis

Other investigations Blood: ESR, serology for syphilis Electromyography of intrinsic laryngeal muscles: a. Normal: Joint fixation, post - scarring b. Fibrillation: Denervation (bad prognosis) c. Polyphasic: Synkinesis, Re-innervation (good prognosis)

Electromyography

Treatment for phonatory gap in U/L abductor or adductor 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

Indications for immediate surgical intervention Electromyography shows fibrillation (complete loss of function with no signs of recovery) Vocal cord palsy due to nerve entrapment in thyroid / bronchial malignancy where recovery is not expected

Per-oral Teflon injection Kleinsasser’s microlaryngoscope introduced Bruning’s syringe loaded with Teflon paste Needle pushed lateral to thyroarytenoid muscle First injection at postero-lateral angle of middle third of vocal cord, 2.5 mm lateral to cord margin Second injection (0.2 ml) made at antero-lateral angle till both cords approximate in phonation I.V. Dexamethasone given for 24 hours

Per-oral Teflon injection

Vocal fold Teflon injection

Percutaneous Teflon injection Needle introduced in midline through crico-thyroid membrane angled 300 - 450 upward & laterally into vocal cord Direct lateral penetration of larynx through thyroid ala is alternate route of injection Vocal cord entered under endoscopic control

Percutaneous Teflon injection

Midline & lateral routes

Vocal fold fat injection

Vocal fold collagen injection

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

Thyroplasty type I

Thyroplasty type I

Thyroplasty type I Horizontal skin incision made over mid-point of thyroid cartilage lamina (from a point 2 cm lateral to midline on opposite side to posterior margin of thyroid cartilage on affected side) Subplatysmal flaps elevated & strap muscles retracted laterally to expose thyroid cartilage Window made in thyroid lamina with scalpel or 1 mm cutting burr, as per Koufman’s formula

Window’s superior border lies at level with vocal cords (midpoint b/w thyroid notch & inferior margin of thyroid cartilage) & its anterior border situated 8 mm posterior to midline Cartilage removal started postero-inferiorly Inner perichondrium elevated off thyroid cartilage & silastic prosthesis inserted Patient asked to phonate while moving silastic prosthesis into its optimal position under flexible laryngoscopy guidance

Type I thyroplasty

Koufman’s formula Window height (mm) = thyroid alar height (mm) – 4 ------------------------------------- 4   Window width (mm) = thyroid alar height (mm) – 4 ------------------------------------ 2 Average = 12 X 6 mm (male); 10 X 5 mm (female)

Insertion of prosthesis

Insertion of silastic prosthesis

Silastic implant

Arytenoid adduction Portion of posterior thyroid cartilage margin cut to expose muscular process of arytenoid Two 4-0 Prolene sutures passed through muscular process & through thyroid cartilage Sutures pulled parallel to lateral cricoarytenoid After optimal medialization of vocal fold, sutures tied on external aspect of thyroid lamina

Arytenoid adduction

Arytenoid adduction

Laryngeal re-innervation Neuromuscular pedicle of superior belly of omohyoid (or sternohyoid) + ansa hypoglossi nerve transferred into thyro-arytenoideus for vocal fold medialization; or posterior crico-arytenoideus for lateralization (Tucker) Neural anastomosis of ansa hypoglossi nerve directly to recurrent laryngeal nerve (Crumley)

Neuromuscular pedicle

Neuromuscular pedicle

Neuromuscular pedicle

Ansa-R.L.N. anastomosis

Combination surgeries Neuromuscular pedicle re-innervation + Thyroplasty type 1 Thyroplasty type 1 + arytenoid adduction Arytenoid adduction has advantage of posterior glottic approximation unlike thyroplasty

Treatment of stridor in B/L abductor paralysis

Tracheostomy: temporary / permanent in acute stridor Vocal cord lateralization: endoscopic, external (King) Vocal cordectomy: external, endoscopic Endoscopic vocal cordotomy: knife, cautery, laser Arytenoidectomy: endoscopic, external (Woodman) Lateralization thyroplasty (Isshiki type II) Laryngeal re-innervation: ansa hypoglossi-omohyoid pedicle transfer into posterior crico-arytenoideus

Vocal cord lateralization (laterofixation / cordopexy)

Vocal cord lateralization Thyroid cartilage exposed via horizontal incision 16-gauge IV cannula inserted through thyroid cartilage 4 mm anterior & 2 mm below mid-point of oblique line, into laryngeal lumen, just above tip of vocal process, under M.L.S. guidance Another 16-gauge IV cannula inserted 5 mm below 1st cannula, just below tip of vocal process

Vocal cord lateralization 1-0 Prolene suture threaded through inferior cannula into laryngeal lumen Suture thread brought out with forceps into laryngeal lumen & inserted into superior cannula External traction put on both suture ends to pull vocal cord laterally to give a 5 mm airway Threads tied over thyroid lamina 8 times

Cordectomy

Cordectomy + lateralization

Posterior cordotomy

Arytenoidectomy

Cordotomy + arytenoidectomy

Thyroplasty type II (lateralization)

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 Sub-perichondrial cricoidectomy Tracheo-esophageal diversion Laryngo-tracheal separation Narrow field laryngectomy

Endolaryngeal stent

Epiglottic flap closure

Epiglottopexy

Epiglottic tube laryngoplasty

Glottic closure

Subperichondrial cricoidectomy

Tracheo-esophageal diversion Proximal trachea anastomosed with esophagus Distal trachea opens into permanent tracheostomy

Laryngo-tracheal separation Proximal trachea closed Distal trachea opens into permanent tracheostomy

Narrow field laryngectomy

Other procedures for aspiration Double cuff tracheostomy Laryngeal suspension Feeding Gastrostomy Feeding Jejunostomy Vocal cord injection Medialization thyroplasty Laryngeal re-innervation Tympanic / Chorda tympani neurectomy

Laryngeal suspension

Other vocal cord surgeries

Thyroplasty type III (shortening) Used for mutational falsetto

Thyroplasty type IV (elongation) Used for raising vocal pitch & ing vocal tension

Evaluation of Hoarseness (dysphonia)

Causes of Hoarseness

Mechanism of hoarseness Loss of approximation of vocal cords: in paralysis, fixation or intervening tumor / lesions Alteration of size of vocal cord: ed in edema, tumor; ed in partial surgical excision, fibrosis Alteration of stiffness of vocal cord: ed in spasmodic dysphonia, fibrosis; ed in paralysis Improper vibration of vocal cord: hyperemia, vocal nodule, vocal polyp

10 organic dysphonia 20 organic dysphonia 1. Congenital * 1. Laryngitis * 2. Laryngeal tumor * 2. Vocal nodule 3. Vocal cord palsy 3. Vocal polyp 4. Spasmodic 4. Reinke’s edema 5. Muscular * Functional dysphonia 6. Neurological * 1. Psychogenic 7. Endocrine * 2. Habitual 8. Senile 3. Puberphonia 9. Fixation by arthritis 4. Ventricular * 10. Traumatic * 5. Malingering

Congenital: laryngomalacia, laryngocoele, haemangioma, web Laryngeal tumor: papilloma, malignancy Muscular: myasthenia gravis Neurological: Parkinsonism, Multiple sclerosis, cerebro-vascular accident, bulbar palsy Endocrine: hypothyroidism, inter-sex, pregnancy Traumatic: accidental, foreign body, intubation Laryngitis: bacterial, viral, TB, allergic, GERD Ventricular: dysphonia plica ventricularis

History taking 1. Duration: > 3 weeks in pt > 40 years is laryngeal malignancy until proven otherwise 2. Progression: due to mass effect or malignancy 3. Voice quality: a. Forced whisper: Organic adductor paralysis b. Faint whisper: Functional adductor paralysis c. Tires with use: U/L abductor paralysis, myasthenia

4. Associated symptoms: a. Stridor: B/L abductor paralysis b. Aspiration: B/L adductor paralysis c. Dysphagia + exertion dyspnea: Ortner’s syndrome d. Hemoptysis: lung malignancy, tuberculosis e. Nasal regurgitation & intonation: high vagal lesion 5. Past history: a. Trauma: accidental, foreign body, intubation b. Surgery: thyroid, intra-thoracic c. Viral upper respiratory tract infection, smoking

Physical Examination Listening to patient’s voice: for hoarseness Indirect laryngoscopy: laryngeal lesions Otoscopy: rule out glomus tumor Neck: lymph node enlargement, thyroid disease Chest: lung malignancy, tuberculosis Cardiovascular: mitral stenosis Neurological: Parkinsonism, multiple sclerosis

Manual compression test Improvement in voice = do thyroplasty (anterior medialization procedure). No improvement in voice = do arytenoid adduction (posterior medialization procedure)

Routine investigations Fibre-optic laryngoscopy Microlaryngoscopy: crico-arytenoid joint mobility CT scan skull base to diaphragm: best X-ray chest: for hemoptysis Ba swallow: for dysphagia Thyroid scan: for thyroid enlargement Panendoscopy: in presence of hard neck node

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