LARYNX by-Dr.SATYAJEET RATH Moderator-Prof M L B BHATT

LARYNXBy-Dr. Satyajeet RathModerator-Dr. Shagun Misra

Topics to be coveredAnatomyRadiological anatomyEpidemiologyRoutes of spreadClinical PresentationExamination

Introduction :-The larynx is an air passage, a sphincter and an organ of phonation Extends from the root of tongue to the trachea.Projects ventrally between the great vessels of the neckLies in anterior midline of neckInfront of C3 to C6 vertebrae

ContdCovered anteriorly by skin, fasciae and the hyoid depressor musclesAbove, it opens into the laryngopharynx and forms its anterior wall Below, it continues into the trachea mobile on deglutition.

Constituents of LarynxCARTILAGES 3 Unpaired - thyroid - cricoid - epiglottis 3 paired cartilages arytenoid corniculate cuneiform

All cartilages are hyaline except epiglottis ,corniculate, cuneiform, vocal process and apex of arytenoid

Cartilages of Larynx

Cartilage of Larynx contd

Membranes and LigamentsExtrinsic: connect thyroid cartilage with epiglottis and hyoid bone ;cricoid cartilage with trachea

Intrinsic: connect cartilages of larynx to each other

LIGAMENTS AND MEMBRANESEXTRINSIC LIGAMENTS AND MEMBRANES

Thyrohyoid membrane Hyo- and thyroepiglottic ligaments Cricotracheal ligament

Intrinsic LigamentsFibroelastic tissue Made up of Quadrate membrane Conus elasticus

Muscles of Larynx and their function

AbductorAdductors

Cricothyroid is the only intrinsic laryngeal muscle lying outside the larynxTransverse arytenoid is the only unpaired intrinsic muscle

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Laryngeal CavityLaryngeal cavity can be divided into 3 parts supraglottis glottis subglottis

Supraglottic LarynxExtend from tip of the epiglottis to superior surface of true vocal cord .Composed of EpiglottisArytenoidAryepiglottic foldFalse vocal cord

Posterior tapering shape reduces area of mucosa in posterior regionMajority of Supraglottic tumors are epiglottic

The inferior boundary of the supraglottis is a horizontal plane passing through the lateral margin of the ventricle at its junction with the superior surface of the vocal cord.

AJCC 2010

The inferior boundary of the supraglottis is a horizontalplane passing through the lateral margin of the ventricleat its junction with the superior surface of the vocal 17

Glottisupper border started from superior surface of true vocal cords Lower border is 0.5 cm below the free edge of true vocal cord. Glottis consists of true vocal cords and the ant and post commisures(mucosa between the arytenoids)True vocal cord are 2 cm long and are thinnest anteriorly and posteriorlyMost lesions arise from free edge and upper surface of ant 2/3

Anterior CommisurePosterior Commisure

Vocal Cords

Subglottic Larynx

It extends from the lower border of glottis to lower border of cricoid cartilage .Consists of a mobile upper and fixed lower part.

MucosaMucosa of glottic and Supraglottic regions is stratified squamous epithelium.Mucosa of ventricles and sub-glottic regions is pseudo-stratified ciliated epitheliumSupra and sub glottic regions particularly ventricles are rich in submucosal mucous or minor salivary glands while glottis is not.

Blood Supplyupper half superior laryngeal artery

lower half-inferior laryngeal artery

Nerve Supply

Contd..

Pre-epiglottic space (Boyers Space)

Anterior: thyrohyoid membrane & thyroid cartilage Posterior: epiglottis elastic cartilageInferior: Petiole attachment to thyroid cartilageConduit :elastic epiglottic cartilage has perforations -direct extension of infrahyoid supraglottic cancer into this fascia-bound spaceBilateral neck drainageOften invaded by advanced cancers

Paraglottic spacequadrangular membrane inferiorlyConus elasticus anteriorly and mediallythyroid cartilage laterally

Reinkes SpaceMucosa over the vocal ligament loosely attached to ligaments.Under the epithelium of vocal cord is a potential space with subepithelial connective tissues.

Radiological Anatomy

LymphaticsGlottic and supraglottic to levels 2-3, subglottic to level 4Very sparce lymphatics in TVC, therefore glottic CA usually better prognosis (although also usually detected earlier)Glottic and subglottic tumors metastasize to ipsilateral lymph nodes, but supraglottic tumors often spread to nodes on both sides of the neck.

Supraglottic lymphaticsSupraglottis has a rich lymphatic network.High propensity for b/l LN mets due to midline location.Primary drainage pattern of supraglottic cancers is the jugular lymph chain.Level 2 nodes mc involved followed by level 3 and 4.Level 5 seldom involved.Level 1b and 1a almost never involved

The risk of clinically involved lymph nodes isapprox. 40% for T 1 and T 2 tumors approx . 60 % for T 3 and T 4 tumors

Lymphatics of subglottisThe first-echelon lymphatics for the subglottic larynx are the Delphian node.The lymphatics in subglottis is less developed.Incidence of lymph node mets varies from 20% to 50%.Lymphatics from subglottis form 3 pedicles: 1 anteriorly and 2 posteriorlyThe anterior channels pass through the cricothyroid membrane and drain into the middle and lower jugular nodes to terminate in the prelaryngeal node(Delphian node),from which lymphatics drain into pretracheal and supraclavicular nodes.

The posterolateral lymphatic channels pass through cricotracheal membrane and terminate in high paratracheal nodes.

Mediastinal involvement can occur,if present is considered a metastasis ( unless it is a level VII mets in which case it is considered regional lymph node metastasis ).

Path of Subglottic Tumor spread

Lymphatics of glottisTrue vocal cords are almost devoid of lymphatics.Incidence of LN mets at diagnosis approaches zero for T1 , 2% for T2 , 15 to 20% for T3 , 20 to 30% for T4.

Lymphatic spread occurs when tumor extends to subglottis or supraglottis.

Lymphatic Drainage contd..With a single lymph node involved by metastatic disease, the prognosis is said to be reduced by half.Criteria that suggest metastatic involvement of a lymph node include enlarged size, abnormal shape, necrosis, and extracapsular spread.Nodal metastasis at the time of presentation is much more common from supraglottic carcinomas when compared with glottic and infraglottic tumors because of the rich supraglottic lymphatic network.The sensitivity of CT and MRI in detecting nodal metastasis is higher than clinical examination and lower than PET.Surg Oncol Clin N Am 23 (2014) 685707

Supra glottis CarcinomaSore throat and odynophagia are the most common presenting symptoms of carcinoma of the supraglottis.Patients often describe the sensation of foreign body and can have difficulty swallowing.Hoarseness occurs in advanced lesions, but is typically absent in early stages.Because of the high incidence of lymph nodes metastasis,a neck mass can be the first sign of carcinoma of the supraglottis.

Supraglottic CarcinomasThe epiglottis is the most frequent location for cancers that arise in the supraglottic larynx. These lesions are often exophytic and circumferential massesTumors of the aryepiglottic fold are typically exophytic lesions that, when detected early, are confined laterally along the aryepiglottic fold.

-Advanced lesions may extend laterally to involve the adjacent wall of the pyriform sinus or medially to invade the epiglottis.

Glottic CarcinomasThe true vocal cords are the most common site of laryngeal carcinomas; the ratio of glottic carcinomas to supraglottic carcinomas is approximately 3:1. The anterior portion of the true vocal cord is the most common location of squamous cell cancer.Most lesions occur along the free margin of the vocal cord.

CONTD..Anteriorly, the tumor may extend to anterior commissure, where it may involve the contralateral true vocal cord. Hoarseness is the most common presenting symptom of early vocal cord cancer.Thus glottis tumours are most commonly diagnosed at early stage.Sore throat.otalgia,localized pain result from cartilage invasion , and dyspnea are symptoms of advanced disease

Sub-glottis CarcinomasSubglottic carcinomas are rare and account for only 5% of all laryngeal carcinomas. When present, these lesions are characteristically circumferential and often extend to involve the undersurface of the true vocal cords They have a tendency for early invasion of the cricoid cartilage and extension through the cricothyroid membrane.

-Visualizing tumor within the cricoid ring is a clear indication of subglottic extension.

Trans-glottic CarcinomasUsually initiate as supraglottic or glottic cancers

As for example Glottic cancers more commonly spread to spraglottic areas.

EpidemiologyMC malignancies of upper aerodigestive tractApprox 25% of head and neck tumors 2.63 % of all body cancer.Primary glottic cancers 3times more common than supraglottic Subglottic cancers are rare80% occur in men.Age group 40- 70 yrs.Most curable of upper aerodigestive tract cancers

GLOBOCAN 2012 (data for ca larynx)INCIDENCEMORTALITY5- YEAR PREVALENCEMen4.8 (22900)4.46.8Women0.50.50.4Both sexes2.5 (25446)2.62.8

INCIDENCEMORTALITY5-YEAR PREVALENCEMen1.91.62.5Women0.30.30.3Both sexes1.11.11.4

INDIAWORLD

NCRP

Risk FactorsSmoking and alcohol are two main risk factorsIn individuals who use both tobacco and alcohol, these risk factors appear to be synergistic, and they result in a multiplicative increase in the risk of developing laryngeal cancer. Human Papilloma Virus 16 & 18Chronic Gastric RefluxPrior history of head and neck irradiation

Occupational exposure to asbestos , diesel fumes , rubber ,wood dustVitamin and nutrient deficiency(subglottic ca)Mutations in p53,ki-67,EGFR,TGF beta,cyclin D1P53 mutation seen nearly in 50% smokers and 55% drinkersTelomerase present in high levels

Routes of spreadLOCAL SPREADNo anatomical barrier to growth from one area to another.Involvement of vocal cords on the external epithelial surface is a late phenomenon but sub mucosal extension by way of para glottic space occur early.Fat space is an important venue for submucosal spread of infrahyoid epiglottis ,false cord and true cord lesions.

Distant Metastasis

Incidence is very low.Identified in appro 10 to 20% cases majority have supraglottic or subglottic primary.Lung(60%) is mc site followed by bones(20%) and liver(10%).Brain mets very rare.

Histological Types95% of laryngeal tumors are squamous cell carcinomaHistologic type linked to tobacco and alcohol abuseCharacterized by epithelial nests surrounded by inflammatory stromaKeratin Pearls are pathognomonic

Other Histological TypesVerrucous CarcinomaPlasmacytomaChondrosarcomaMalignant Minor salivary carcinomaPsuedosarcomaCarcinoidPlasmacytomaChemodectoma

PresentationHoarsenessMost common symptomSmall irregularities in the vocal fold result in voice changesChanges of voice in patients with chronic hoarseness from tobacco and alcohol can be difficult to appreciate

ContdPatients presenting with hoarseness should undergo an indirect mirror exam and/or flexible laryngoscope evaluationMalignant lesions can appear as friable, fungating, ulcerative masses or be as subtle as changes in mucosal colorVideo laryngoscopy may be needed to follow up these subtler lesions

Supraglottic carcinoma- Often silent throat pain dysphagia referred pain in ear neck mass respiratory obstruction halitosis hoarseness of voice late symptom

Glottic carcinoma Hoarseness of voice (early sign) Stridor Weight loss ,halitosis, aspiration can occur with locally advanced disease.Sore throat, localized pain from cartilage invasion , dyspnoea are symptoms of advanced disease.Ca subglottis rare.Usually diagnosed late.

Other symptoms include:DysphagiaHemoptysisThroat painEar painAirway compromiseAspirationNeck mass

HistoryHistory- Any patient in cancer age group having persistent or gradually increase hoarseness of voice x 3 weeks must be consider for further evaluation .

personal historyFamily historyOccupational history

ExaminationGood neck examination looking for cervical lymphadenopathy and broadening of the laryngeal prominence is requiredThe base of the tongue should be palpated for masses as wellRestricted laryngeal crepitus may be a sign of post cricoid or retropharyngeal invasion

ExaminationSee for Appearance of lesion Suprahyoid- exophyticInfrahyoid- ulcerativeVocal cord nodular/ ulcer/ thickenedAnt commissure- granulation tissueSubglottic raised submucosal tissue

Vocal cord mobility Fixation indicate infiltration into Thyroarytenoid Cricoarytenoid Invlovment of recurrent laryngeal nerveExtent of disease

Examination of neck

lymphnode mass extralaryngeal spread - palpation of diffuse firm fullness above the thyroid notch with widening of space between hyoid and thyroid indicate invasion of preepiglottic space. growth through cricohyoid membrane may produce midline swelling.thyroid cartilage invasion may cause perichondritis and on palpation may be tender .

Diagnostic EvaluationCareful history and clinical examination.D/L scopy and biopsy is the most valuable step in diagnosis and staging.Rigid endoscope requires anaesthesia,better visualisation of subglottis and ant commissure.Assesment of vocal cord mobility

CT SCANCECT and contrast MRI are useful in diagnostic imaging.Preferably done before biopsy.In cancers of the larynx, cross-sectional imaging with CT provides valuable information regarding primary tumor staging and treatmentMalignancies of the larynx are primarily imaged with CT, because of lower image degradation from breathing , swallowing and coughing during examination.CT and MRI play a superior role, especially in evaluating the deep spaces of the head and neck.

ContdCharacteristics such as tumor volume, sclerosis of laryngeal cartilage on CT have been found to have prognostic value.Limitations of CT include subtle evaluation of tumor induced cartilage and bone defects , detection of superficial tumors.CT evaluation is much faster than MRI and has practical advantages as cost , speed and availability.CT Scan is used for lymph node delineation and radiotherapy contouring.MRI is more resource-intensive and less available than CT.

MRI ScanStaging accuracy for MRI in ca larynx is higher due to more accurate assessment of cartilage invasion , pre epiglotic and paraglottic extension.Gross cartilage invasion can be detected on CT; however, early cartilage abnormalities are detected better on MRI.Areas of cartilage involvement result in high signal intensity on T2W images and contrast-enhanced T1W images.Surg Oncol Clin N Am 23 (2014) 685707

PET ScanThe role of PET scan in the routine initial work up remains investigational.Useful in detection of occult nodal and distant mets.To distinguish between recurrence and post treatment changes.A pretreatment standardized uptake value (SUV) of less than 9.0 in the primary tumor has been shown to be associated with less frequency of disease recurrence and improved disease-free survival.PET/CT is the modality of choice for therapy assessment and is performed 12 weeks after completion of chemoradiation.Surg Oncol Clin N Am 23 (2014) 685707

Direct Laryngoscopy

Indirect Laryngoscopy contdPatient is seated opposite the examiner.Asked to protrude the tongue which is wrapped in gauzeAnd held by examiner b/w thumb and middle finger .Index finger is used to keep upper lip out of way.Warm the laryngeal mirror , introduced into the mouth and held firmly against uvula and soft palate .To see movement of cords asked the patient to take deep inspiration , say Aa (adduction ) and Eee (for adduction and tension ).

Indirect Laryngoscopy

Metastatic Work upChest xray sufficient in early stages at low risk for mets.CT scan in locally advanced disease.PET scan in detection of distant mets.PFTs for patients considered for surgery.Bronchoscopy and oesophagoscopy to rule out synchronous tumours.Routine lab tests include complete blood count,LFTs.Attention to anemia.

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