LARYNGEAL LARYNGEAL PARALYSISPARALYSIS

DEPT OF OTORHINOLARYNGOLOGY

J J M M CDAVANAGERE

NERVE SUPPLY OF LARYNX

• Superior laryngeal nerve-internal branch is sensory supplies larynx above the level of vocal cords and external branch supplies cricothyroid muscle.

• Recurrent laryngeal nerve-Motor branch supplies all muscles of larynx except the cricothyroid and sensory branch supplies subglottis

RECURRENT LARYNGEAL NERVE (RLN)

• Right RLN arises from vagus, hooks around subclavian artery and ascends upwards in tracheo-oesophageal groove

• Left RLN arises from vagus, hooks around arch of aorta and ascends upwards in tracheo-oesophageal groove

• Left RLN has longer course thus its prone for injury

SUPERIOR LARYNGEAL NERVE (SLN)

• Arises in inferior ganglion of vagus, descends behind internal carotid artery and at the level of greater cornua of hyoid it divides into internal and external branches

CLASSIFICATION OF LARYNGEAL PARALYSIS

• May be unilateral or bilateral and may involve

1. Recurrent laryngeal nerve2. Superior laryngeal nerve3. Both recurrent and superior

laryngeal nerve (combined or complete paralysis)

CAUSES OF LARYNGEAL PARALYSIS

• Supranuclear: Rare• Nuclear: involvement of nucleus

ambiguus in medulla, usually associated with other lower cranial nerve paralysis

• High vagal lesions: may be involved at the level of jugular foramen or parapharyngeal space

• Low vagal or RLN • Systemic causes: diabetes mellitus,

diphtheria, typhoid, lead poisoning• Idiopathic: in about 30% of cases

RLN PARALYSIS

•UnilateralResults in ipsilateral paralysis

of all intrinsic muscles except the cricothyroid

Vocal cord assumes a median or paramedian position and does not move laterally on deep inspiration

RLN PARALYSIS -SEMON’S LAW

• This law explains median or paramedian position of the vocal cords

• It states that ‘In all progressive In all progressive lesions of RLN, abductor fibres of lesions of RLN, abductor fibres of the nerve, which are the nerve, which are phylogenetically newer, are more phylogenetically newer, are more susceptible and thus first to be susceptible and thus first to be paralysed compared to adductor paralysed compared to adductor fibresfibres’

RLN PARALYSIS- WEGNER AND GROSSMAN HYPOTHESIS

• It states that cricothyroid muscle which receives innervation from superior laryngeal nerve keeps the cord in paramedian position due to adductor function

RLN PARALYSIS CLINICAL FEATURES

• May be undetected as 1/3rd of patients remain asymptomatic

• Some patients may complain of change of voice

• Voice gradually improves due to compensation by healthy cord which crosses the midline to meet paralysed one

• Treatment: Generally treatment is not required

RLN PARALYSIS

• Bilateral RLN paralysisAetiology: neuritis and trauma

(thyroidectomy) are the most common causes. The condition is often acute in onset

Position of cords: as all the intrinsic muscles are paralysed the vocal cords lie in median or paramedian position due to unopposed action of cricothyroid

RLN PARALYSIS- CLINICAL FEATURES

• The airway is inadequate causing dyspnoea and stridor but the voice is good

• Dyspnoea and stridor become worst during exertion or during attacks of acute laryngitis

• Treatment: Tracheostomy / vocal cord lateralization procedures

LATERALISATION OF VOCAL CORD

• Aim to move and fix the cord in lateral position to improve the airway

• Various procedures areArytenoidectomy: can be done by

external approach, endoscopic or by using LASER

Thyroplasty type 2Cordectomy: can be done through

external, endoscopic or by using LASERNerve muscle implant: sternohyoid

muscle with its nerve supply is transplanted into the paralysed posterior cricoarytenoid to bring some movement

SLN PARALYSIS

• Unilateral Unilateral Usually it’s a part of combined

paralysis, isolated lesions are rare

Causes paralysis of cricothyroid muscle and ipsilateral anesthesia of the larynx above the vocal cord

SLN PARALYSIS- CLINICAL FEATURES

• Voice is weak and pitch can not be raised

• Occasional aspiration may be present

• Askew position of glottis as anterior commissure is rotated to the healthy side

• Shortening of the cord with loss of tension

• As tension of the cord is lost , it sags down during inspiration and bulges up during expiration

SLN PARALYSIS

• Bilateral Bilateral This is uncommon conditionBoth Cricothyroids are paralysed along

with anesthesia of upper part of larynxEtiology: surgical, accidental trauma,

neuritis, neoplastic (pressure by metastatic lymph nodes)

Clinical features: weak and husky voice, aspiration causing cough and choking fits

SLN PARALYSIS- TREATMENTSLN PARALYSIS- TREATMENT

• Depends on cause, neuritis recovers spontaneously

• Troublesome aspiration requires tracheostomy with cuffed tube and esophageal feeding tube

• Epiglottopexy is an operation to close laryngeal inlet to protect the lungs from repeated aspiration, it’s a reversible process

COMBINED (COMPLETE) PARALYSIS

• UnilateralUnilateral This causes paralysis of all the muscles of

larynx on one side except interarytenoid which receives innervation from the opposite side

EtiologyEtiology: thyroid surgery is the most common cause

It may also occur in the lesions of nucleus ambiguus or that of the vagus nerve proximal to origin of SLN

Thus lesion may lie in medulla, posterior cranial fossa, jugular foramen or parapharyngeal space

COMBINED (COMPLETE) PARALYSIS

• Clinical features:Clinical features:Vocal cord will lie in cadeveric

positionHealthy cords fails to compensate This causes hoarseness of voice

and aspiration of liquids through the glottis

Cough is ineffective due to air waste

COMBINED PARALYSIS- TREATMENT

• Speech therapy• Procedures to medialise the cordInjection of Teflon pasteThyroplasty type 1Muscle or cartilage implantArthrodesis of cricothyroid joint

COMBINED PARALYSIS

• Bilateral Bilateral Both RLN and SLN are paralysed

on both sidesBoth cords lie in cadeveric

position and there is total anaesthesia of the larynx

COMBINED PARALYSIS- BILATERAL

•Clinical features

AphoniaAspirationInability to coughBronchopneumonia

COMBINED PARALYSIS- BILATERAL

• Treatment:Treatment:TracheostomyEpiglottopexy: epiglottis is

folded backwards and fixed to the arytenoids

Vocal cord plicationTotal laryngectomy

CONGENITAL VOCAL CORD PARALYSIS

• May be unilateral or bilateral• Unilateral is more common• May be due to birth trauma, congenital

anomalies of great vessels of heart• Bilateral paralysis may be due to

hydrocephalus, arnold-chiari malformations, intracerebral hemorrhage during birth, meningocoele, nucleus ambiguus agenesis

PHONOSURGERY

• Surgical procedures designed to improve quality of voice

Excision of benign or malignant lesions by Microlaryngeal surgery or laser

Teflon paste injection to vocal cordsThyroplasty Laryngeal reinnervation procedures:

segment of anterior belly of omohyoid muscle carrying its nerve and vessels is implanted into thyroarytenoid muscle

THYROPLASTY

• ISSHIKI CLASSIFICATIONISSHIKI CLASSIFICATIONType 1: medialization Type 1: medialization Type 2: lateralizationType 2: lateralizationType 3: shorteningType 3: shorteningType 4: lengthening Type 4: lengthening

( tightening) ( tightening)