congenital laryngeal anomalies - lectures/larynx/2...4/14/2009 1 congenital laryngeal anomalies...

4/14/2009

1

Congenital Laryngeal Anomalies

Prof. Hesham Abd Al-FattahAlexandria - Egypt

Embryology

•Resp primordium 3rd wk•Resp primordium separatedby tracheoesophageal folds•Fuse to form septum (4-5wks)•Larynx from 4th & 6th arches•Primitive larynx altered by h b hi l ihypobranchial eminence, epiglottis, arytenoids•Laryngeal lumen obliterated and recanalized

4/14/2009

2

ANATOMICAL DIFFERENCESANATOMICAL DIFFERENCES

1 Smaller air way

•Vestibule

•subglottis1. Smaller air-way 2. Shorter air-way3. Loose submucosa4. Rich lymphatics 5. Shape of the epiglottis6. Soft Cartilages7. Higher in position

subg ott s

In AdultsIn Adults >>22//33In ChildrenIn Children >>11//22((1 1 mm subglottic narrowing mm subglottic narrowing

==3232% Lumen reduction)% Lumen reduction)

Narrowing>>> sever air way distressNarrowing>>> sever air way distress

New Born subglottic = New Born subglottic = 44..55mmmmNonNon--pass of pass of 3 3 mm bronchoscope =mm bronchoscope =Subglottic StenosisSubglottic Stenosis

DiagnosisDiagnosisHistoryHistoryCli i l Pi tCli i l Pi tClinical PictureClinical PictureInvestigation:Investigation:

RadiographyRadiographyNeck films, chest filmsNeck films, chest filmsBarium swallowBarium swallowBarium swallowBarium swallowMultiMulti--slice CT with virtual endoscopy/ slice CT with virtual endoscopy/ rarely MRI rarely MRI (when there is swelling to determine its nature)(when there is swelling to determine its nature)

Flexible Endoscopy, Flexible Endoscopy, If the stridor is not severIf the stridor is not sever

Endoscopy in OR is the Endoscopy in OR is the Gold standardGold standard

4/14/2009

3

ClassificationClassificationSite:Site:

Supraglottic Supraglottic –– Glottic Glottic –– Subglottic.Subglottic.St tSt tStructure:Structure:

Cartilage Cartilage –– nerve nerve –– joint joint –– BV.BV.Incidence of occurrence:Incidence of occurrence:

Laryngomalacia.Laryngomalacia.Vocal Fold paralysisVocal Fold paralysisVocal Fold paralysis.Vocal Fold paralysis.Subglottic stenosis.Subglottic stenosis.Subglottic Haemangioma.Subglottic Haemangioma.Other.Other.

LaryngomalaciaLaryngomalaciaMost common (Most common (6060%)%)

M:F =M:F = 22 :: 11M:F = M:F = 2 2 : : 11

Etiology:Etiology:Immaturity of cartilageImmaturity of cartilage

Immature neuromuscular c.Immature neuromuscular c.•• No difference between the quality of the cartilage structures inNo difference between the quality of the cartilage structures in

GERD.GERD.No difference between the quality of the cartilage structures in No difference between the quality of the cartilage structures in

infants with laryngomalacia and those who have normal infants with laryngomalacia and those who have normal development.development.

••an increase in the incidence of Laryngomalacia does not occur in an increase in the incidence of Laryngomalacia does not occur in premature infants who have classic hypotonicity.premature infants who have classic hypotonicity.

•• Inflammation of variable intensity beneath the epithelium with Inflammation of variable intensity beneath the epithelium with edema deep to it. edema deep to it.

4/14/2009

4

ClinicalClinical

LaryngomalaciaLaryngomalaciaDiagnosisDiagnosis •Inspiratory stridor

•Starting usually few weeks after birth

• Most cases are mild & it is the noise hi h th t

RadiologicalRadiological

Endoscopy:Endoscopy:Flexible endoscopy.Flexible endoscopy.

which annoys the parents

•Self limiting, disappear between 18-24 months of age

•If the stridor is sever, other anomalies needs to excluded

Rigid endoscopy Rigid endoscopy GA or NO GA !!!! muscle relaxant.GA or NO GA !!!! muscle relaxant.

I) Epiglottis : Omega shaped /Floppy .I) Epiglottis : Omega shaped /Floppy .

LaryngomalaciaLaryngomalaciaEndoscopic findingsEndoscopic findings

) p g g p / ppy) p g g p / ppy

II) AE fold : Short / Inwarding.II) AE fold : Short / Inwarding.

III) Arytenoid : Redundant MM/ bulky.III) Arytenoid : Redundant MM/ bulky.

IV) Discoordinate pharyngolaryngomalaciaIV) Discoordinate pharyngolaryngomalacia::Complete collapse of supraglottic structures.Complete collapse of supraglottic structures.

No anatomical abnormalities.No anatomical abnormalities.

V) Posteriorly displaced Lat Glossoepi FoldV) Posteriorly displaced Lat Glossoepi Fold

4/14/2009

5

LaryngomalaciaLaryngomalacia

GradesGrades

II IIII IIIIII

Assurance /observation Assurance /observation

T t GERDT t GERD


Treat GERD.Treat GERD.

Surgical treatment: (Indications)Surgical treatment: (Indications)

Severe stridor with failure to thrive.Severe stridor with failure to thrive.

Weight loss chest deformityWeight loss chest deformityWeight loss, chest deformity.Weight loss, chest deformity.

Cyanotic attacks, Cor pulmonale.Cyanotic attacks, Cor pulmonale.

Hypoxemia and Hypercapnia.Hypoxemia and Hypercapnia.

4/14/2009

6

LaryngomalaciaLaryngomalaciaSurgical treatment:Surgical treatment:

Tracheostomy.Tracheostomy.

Supraglottoplasty:Supraglottoplasty:

Division of the AE fold.Division of the AE fold.

Removal of the redundant Removal of the redundant suprasupra--arytenoid mucosa andarytenoid mucosa andsuprasupra arytenoid mucosa and arytenoid mucosa and lateral borders of epiglottis.lateral borders of epiglottis.

Suprahyoid epiglottectomy.Suprahyoid epiglottectomy.


Surgical treatment:Surgical treatment:Surgical treatment:Surgical treatment:Tracheostomy.Tracheostomy.



Removal of the redundantRemoval of the redundantRemoval of the redundant Removal of the redundant suprasupra--arytenoid mucosa arytenoid mucosa and lateral borders of and lateral borders of epiglottis.epiglottis.


4/14/2009

7

LaryngomalaciaLaryngomalaciaSurgical treatment:Surgical treatment: Floppy EpiglottisFloppy Epiglottis

Tracheostomy.Tracheostomy.



Removal of the redundant supraRemoval of the redundant supra--arytenoid mucosa and lateral bordersarytenoid mucosa and lateral bordersarytenoid mucosa and lateral borders arytenoid mucosa and lateral borders of epiglottis.of epiglottis.


1Long Tubular epi

Redudent arytenoid

2..\video & pictures\cong anomalies larynx\MOV01269.AVISupraglottoplasty

4/14/2009

8

Cong. VC ParalysisCong. VC Paralysis•The second most common anomaly (15-20%)•M = F

Bilateral:Bilateral:Neuromuscular Neuromuscular immaturity.immaturity.CNS anomaliesCNS anomalies

Unilateral:Unilateral:Birth trauma.Birth trauma.Mediastinal lesions.Mediastinal lesions.

M F

CNS anomalies.CNS anomalies.Birth trauma.Birth trauma.Idiopathic.Idiopathic.

Iatrogenic.Iatrogenic.

Cong. VC ParalysisCong. VC ParalysisClinical presentation:

Bilateral:Bilateral:Insp. Stridor:Insp. Stridor:

after birth immediatelyafter birth immediatelySevere Severe airway airway support.support.

Unilateral:Unilateral:Few weeks after birth or Few weeks after birth or pass unnoticed.pass unnoticed.Hoarse breathy cry.Hoarse breathy cry.Aspiration (rare)Aspiration (rare)Voice Voice nearnear--normal.normal.

Aspiration.Aspiration.

Aspiration (rare).Aspiration (rare).

4/14/2009

9

Cong. VC ParalysisCong. VC Paralysis

Diagnosis:Diagnosis:Diagnosis:Diagnosis:Endoscopy:Endoscopy:

Flexible (mild airway distress)Flexible (mild airway distress)

Rigid (severe airway distress)Rigid (severe airway distress)

Radiological (CNS chest)Radiological (CNS chest)Radiological (CNS, chest)Radiological (CNS, chest)

4/14/2009

10


Diagnosis:Diagnosis:Diagnosis:Diagnosis:Endoscopy:Endoscopy:

Flexible (mild airway distress)Flexible (mild airway distress)

Rigid (severe airway distress)Rigid (severe airway distress)

R di l i l (CNS h t)R di l i l (CNS h t) Bulbar MyasthesiaRadiological (CNS, chest)Radiological (CNS, chest) Bulbar Myasthesia

Management:Management:


Management:Management:I) Unilateral:I) Unilateral:

Observation.Observation.

Upright positionUpright positionUpright position. Upright position.

Tracheostomy (severe aspiration)Tracheostomy (severe aspiration)

4/14/2009

11

Management:Management:


Management:Management:II) Bilateral:II) Bilateral:

Treatment of cause e.g. shunt op.Treatment of cause e.g. shunt op.

Tracheostomy and FTracheostomy and F--U (U (11--22 years):years):Tracheostomy and FTracheostomy and F U (U (11 2 2 years):years):

Spont. Recovery (>Spont. Recovery (>5050%) %) Decannulation.Decannulation.

No recovery No recovery Lateralization procedure.Lateralization procedure.

Cong. VC ParalysisCong. VC ParalysisVC Lateralization:VC Lateralization:

ArytenoidectomyArytenoidectomy

Open.Open.

EndoscopicEndoscopicEndoscopic.Endoscopic.

Laser cordotomy.Laser cordotomy.

4/14/2009

12


VC L t li tiVC L t li tiVC Lateralization:VC Lateralization:

ArytenoidectomyArytenoidectomy

Open.Open.

Endoscopic.Endoscopic.

Laser cordotomy.Laser cordotomy.

Cong. SG StenosisCong. SG StenosisSG lumen < SG lumen < 4 4 mm in full term & < mm in full term & < 3 3 mm in mm in premature. premature. ( N = ( N = 44..5 5 mm)mm)

33rdrd common anomaly.common anomaly.

Cartilaginous X Soft tissue.Cartilaginous X Soft tissue.

Four grades:Four grades: (Cotton grading)(Cotton grading)I = < I = < 5050% Obst.% Obst.

II = II = 51 51 –– 7070% Obst.% Obst.

III = III = 71 71 –– 9999% Obst.% Obst.

IV = No lumen.IV = No lumen.

4/14/2009

13

Clinical presentation:Clinical presentation:

Cong. SG StenosisCong. SG Stenosis

Clinical presentation:Clinical presentation:Mild:Mild:

Persistent / Rec. croup.Persistent / Rec. croup.

Difficulty intubation during general Difficulty intubation during general anesthesiaanesthesiaanesthesia.anesthesia.

Difficult Decannulation after tracheostomyDifficult Decannulation after tracheostomy

Severe:Severe:Upper airway obstruction after birth.Upper airway obstruction after birth.


Diagnosis:Diagnosis:Diagnosis:Diagnosis:Endoscopy:Endoscopy:“SG stenosis is an endoscopic “SG stenosis is an endoscopic diagnosis” (Cotton RT. Otol. diagnosis” (Cotton RT. Otol. Clinic N Am. Clinic N Am. 20002000))

Passing ET or bronchoscope of Passing ET or bronchoscope of known diameter.known diameter.Exclude ass. anomalies.Exclude ass. anomalies.

4/14/2009

14


Diagnosis:Diagnosis:Plain XPlain X rayrayPlain XPlain X--rayrayCT scanCT scan33D CT scanD CT scanVirtue endoscopyVirtue endoscopy


Management:Management:Management:Management:FollowFollow--up (Child outgrow up (Child outgrow the problem)the problem)

Tracheostomy & FU.Tracheostomy & FU.

Endoscopic (laser) dilation:Endoscopic (laser) dilation:Endoscopic (laser) dilation: Endoscopic (laser) dilation: limited role.limited role.

Only for soft stenosis.Only for soft stenosis.

Surgical treatment.Surgical treatment.

4/14/2009

15

Cong. SG StenosisCong. SG StenosisSurgical Surgical

treatment:treatment:Anterior Cricoid Split:Anterior Cricoid Split:


SurgicalSurgicalSurgical Surgical treatment:treatment:Laryngotracheoplasty:Laryngotracheoplasty:

4/14/2009

16


SurgicalSurgicalSurgical Surgical treatment:treatment:Laryngotracheoplasty: Laryngotracheoplasty: Costal cartilageCostal cartilage


SurgicalSurgicalSurgical Surgical treatment:treatment:Laryngotracheoplasty: Laryngotracheoplasty: Strap musclesStrap muscles

4/14/2009

17

SG HaemangiomaSG HaemangiomaCongenital vascular malformation of mesodermal resets. Congenital vascular malformation of mesodermal resets. 11..55% of cong. laryngeal anomalies.% of cong. laryngeal anomalies.M : F = M : F = 1 1 : : 223030% at birth usually starts to grow% at birth usually starts to grow 66 1818 monmon UAOUAO3030% at birth, usually starts to grow % at birth, usually starts to grow 66--18 18 mon mon UAOUAOStridor ( Mixed long insp & short exp) feeding problems laterUsually involutes by the age Usually involutes by the age 4 4 –– 5 5 ys.ys.Associated With other haemangiomata of H&N (Associated With other haemangiomata of H&N (5050%)%)

SG HaemangiomaSG Haemangioma

Diagnosis:Diagnosis:Diagnosis:Diagnosis:Radiological.Radiological.Rigid endoscopyRigid endoscopy

4/14/2009

18

SG HaemangiomaSG HaemangiomaManagement:Management:11 Tracheotomy and followTracheotomy and follow--up for spontaneousup for spontaneous11. Tracheotomy and follow. Tracheotomy and follow up for spontaneous up for spontaneous

regression (regression (22--4 4 ys.).ys.).

22. Corticosteroid (systemic or intralesional). Corticosteroid (systemic or intralesional)

33. Laser endoscopic surgery (KTP/CO. Laser endoscopic surgery (KTP/CO22).).

44. Interferon.. Interferon.

55. Cryosurgery.. Cryosurgery.

66. External irradiation.!!!!!. External irradiation.!!!!!

77. Surgical excision.. Surgical excision.

SG HaemangiomaSG Haemangioma

ManagementManagement

Repeated Laser debulking

(Laser Fibrosis SG stenosis)

Tracheostomy & FU 4-5 ys.

Non involuting InvolutionNon involuting

Surgical excision

Involution

Decannulation

4/14/2009

19

S G HaemangiomaS G Haemangioma

P t P liP t P liPresent PolicyPresent PolicyTracheostomy

Laser Debulking Once Only

Mitomycin-C

Decannulation

4 Cases > 2 ys

4/14/2009

20

Vijayasekaran S,. White D R, Hartley B EJ, Rutter M J, Elluru RG, Cotton RTOpen Excision of Subglottic Haemangiomas to Avoid Tracheostomy

Arch Otolaryngol Head Neck Surg. 2006;132:159-163.

Laryngeal WebLaryngeal WebFailure of reFailure of re--canalization.canalization.Site:Site:Site:Site:

Glottic.Glottic.SupraglotticSupraglotticSubglottic.Subglottic.

Size:Size:Thin.Thin.Thick (associated SG stenosis)Thick (associated SG stenosis)

4/14/2009

21

Laryngeal WebLaryngeal Web

Diagnosis:Diagnosis:Diagnosis:Diagnosis:Endoscopy.Endoscopy.Radiological.Radiological.

Management:Management:Excision:Excision:

ThinThin MLSMLS –– LaserLaserThin Thin MLS MLS Laser.Laser.Thick Thick LaryngofissureLaryngofissure

Prevent recurrence:Prevent recurrence:Keel.Keel.Mitomycin.Mitomycin.

Laryngeal WebLaryngeal Web1. Endoscopic keel insertion:

4/14/2009

22



4/14/2009

23

22 Mitomycin application:Mitomycin application:

Laryngeal WebLaryngeal Web

22. Mitomycin application:. Mitomycin application:Local application for Local application for 5 5 minutes.minutes.

Inhalation by nebulizer: Inhalation by nebulizer: 11//2 2 cc of diluted MMC every cc of diluted MMC every 8 8 hrs. for hrs. for 3 3 weeksweeks

I h l ti it i C i th t fInhalation mitomycin-C in the management of laryngeal fibrosis: rationale, benefits, and pitfalls.

Hesham A. Fattah*, Ashraf Hamza*, Alaa Gaafar*, Mervat Hamza**, Zinab Mourad***

International Congress Series 2426 (2003)

Laryngeal papillomatosisLaryngeal papillomatosisHuman Papilloma Virus (Human Papilloma Virus (6 6 & & 1111))

Bimodal age distribution (<Bimodal age distribution (<22 && 2020 ys )ys )Bimodal age distribution (<Bimodal age distribution (<2 2 & & 20 20 ys.)ys.)

Risk factors:Risk factors:Teenage mother.Teenage mother.

First born child.First born child.

V i l d liV i l d liVaginal delivery.Vaginal delivery.

Clinical presentation:Clinical presentation:Change of voice (early)Change of voice (early)

Airway obstruction.Airway obstruction.

4/14/2009

24

Laryngeal papillomatosisLaryngeal papillomatosis

Diagnosis:Diagnosis:ggEndoscopic.Endoscopic.

Management:Management:Tracheostomy.Tracheostomy.

Laser debulking.Laser debulking.

Antiviral drugs.Antiviral drugs.

Mitomycin.Mitomycin.

Histologic characterization of human papilloma virus in Histologic characterization of human papilloma virus in respiratory papillomas after Mitomycinrespiratory papillomas after Mitomycin--C applicationC application

Hesham Abd AlHesham Abd Al--Fattah, Ashraf Hamza, Manal Nasr, Fattah, Ashraf Hamza, Manal Nasr, University of Alexandria, Egypt.University of Alexandria, Egypt.

10 months

3wks +2 wks off

2.5 ys Laser evaporation

Histopathology and PCR data failed to identify any HPV pathology or DNA in all remission specimens.

4/14/2009

25

Laryngeal CystLaryngeal Cyst

Types:Types:Types:Types:Saccular cystSaccular cystDuctal cyst.Ductal cyst.Duplication cyst.Duplication cyst.Thyroglossal cyst.Thyroglossal cyst.Cyst in ectopic thyroid Cyst in ectopic thyroid glandglandgland.gland.

Management:Management:Endoscopic excision.Endoscopic excision.Surgical excision.Surgical excision.

Cystic HygromaCystic Hygroma

Dilated lymphatic Dilated lymphatic spaces.spaces.spaces.spaces.Invade the larynx Invade the larynx UAO UAO 11stst year.year.Diagnosis:Diagnosis:

Endoscopy.Endoscopy.RadiologicalRadiologicalRadiological.Radiological.

Management:Management:Tracheostomy.Tracheostomy.Laser ablation.Laser ablation.Surgical excision.Surgical excision.

4/14/2009

26

Cri Du Chat SyndromeCri Du Chat Syndrome

Chromosomal abnormalityChromosomal abnormalityChromosomal abnormality, Chromosomal abnormality, 11//5050,,000 000 birthsbirths

Criteria:Criteria:Growth retardation, Growth retardation, microcephaly.microcephaly.CVS defects, skeletal CVS defects, skeletal b litib litiabnormalities.abnormalities.

Mowing cry & high Mowing cry & high pitched stridor (paralysis pitched stridor (paralysis of interarytenoid muscle).of interarytenoid muscle).Triangular epiglottis.Triangular epiglottis.

Management of a ChildManagement of a ChildManagement of a Child Management of a Child with Congenital with Congenital

Laryngeal AnomalyLaryngeal Anomaly

4/14/2009

27

11. History:. History:I) Respiratory distress I) Respiratory distress ++ cyanotic cyanotic

attacks:attacks:Relieved by crying = Supralaryngeal Relieved by crying = Supralaryngeal obstruction (e.g. choanal atresia)obstruction (e.g. choanal atresia)Onset:Onset:

11.. Immediately after birth:Immediately after birth:SG stenosis Cong VC paralysisSG stenosis Cong VC paralysisSG stenosis, Cong. VC paralysisSG stenosis, Cong. VC paralysis

22.. Delayed:Delayed:Laryngomalacia (Laryngomalacia (11stst week)week)Laryngeal hemangioma (Laryngeal hemangioma (11stst 6 6 months)months)

11. History:. History:II)II) Change of voice:Change of voice:

Muffled voice = Supraglottic cystMuffled voice = Supraglottic cystMuffled voice = Supraglottic cystMuffled voice = Supraglottic cystWeak or absent voice (cry):Weak or absent voice (cry):

Laryngeal web.Laryngeal web.Severe subglottic stenosisSevere subglottic stenosis

III)III)A i tiA i tiIII)III)Aspiration:Aspiration:Laryngeal cleft.Laryngeal cleft.VC paralysis.VC paralysis.

4/14/2009

28

22. Examination:. Examination:


4/14/2009

29

VC DysfunctionVC DysfunctionDef.:Def.:

Paradoxical mov. of VC Paradoxical mov. of VC abnormal adduction of the abnormal adduction of the anterior part during inspiration.anterior part during inspiration.

Etiology: Etiology: lesion affects the Vagus nerve lesion affects the Vagus nerve alter laryngeal alter laryngeal tone tone dec. laryngeal threshold for stimuli. e.g. dec. laryngeal threshold for stimuli. e.g. Bulbar Myesthenia GravisBulbar Myesthenia Gravis..

Clinically:Clinically:yyChange of voice.Change of voice.Stridor.Stridor.CoughCoughAttacks of laryngeal spasm.Attacks of laryngeal spasm.Wheezy chest (miss diagnosis as B.A)Wheezy chest (miss diagnosis as B.A)

4/14/2009

30

VC DysfunctionVC Dysfunction

Diagnosis:Diagnosis:Diagnosis:Diagnosis:Endoscopic ex. of the larynxEndoscopic ex. of the larynx

Post. Glottic chink while ant. Parts of VC are Post. Glottic chink while ant. Parts of VC are adducted.adducted.


4/14/2009

31

Use of stents in Paediatric Age GpUse of stents in Paediatric Age GpDumon

Silmet Montgomery

Cases of congenital laryngeal anomalies Cases of congenital laryngeal anomalies

presented to ORL & Pediatric presented to ORL & Pediatric

Departments Departments –– Alexandria University in the Alexandria University in the

period from January period from January 2002 2002 –– January January 20052005. .

(endoscopically + Radiologically)(endoscopically + Radiologically)

5656 cases:cases:56 56 cases: cases:

32 32 boys : boys : 5757%%

24 24 girls : girls : 4343%%

4/14/2009

32


Surgical treatment:Surgical treatment:Surgical treatment:Surgical treatment:Tracheostomy.Tracheostomy.



Removal of the redundantRemoval of the redundantRemoval of the redundant Removal of the redundant suprasupra--arytenoid mucosa and arytenoid mucosa and lateral borders of epiglottis.lateral borders of epiglottis.


ResultsResults

Laryngomalacia:Laryngomalacia:Cong VC parlaysisCong VC parlaysis

17 17 + + 1 1 (VC paralysis) (VC paralysis) 3232%%77 1313%%Cong. VC parlaysisCong. VC parlaysis

Cong. SG stenosis:Cong. SG stenosis:Laryngeal web:Laryngeal web:SG hemangioma:SG hemangioma:Papilloma:Papilloma:

77 1313%%88 1414%%7 7 + + 1 1 (SG stenosis)(SG stenosis) 1414%%44 77%%66 1010..55%%pp

Laryngeal cyst:Laryngeal cyst:VC dysfunction:VC dysfunction:Cri du chat:Cri du chat:Cystic hygroma:Cystic hygroma:

22 33..55%%11 22%%11 22%%11 22%%

4/14/2009

33

ConclusionConclusion

Laryngomalacia, VC paralysis and SG Laryngomalacia, VC paralysis and SG stenosis are the most common congenital stenosis are the most common congenital laryngeal anomalies.laryngeal anomalies.

Endoscopy is the gold standard Endoscopy is the gold standard investigation in cases of congenital investigation in cases of congenital laryngeal anomalies.laryngeal anomalies.

Management depends on the severity and Management depends on the severity and the degree of the disease.the degree of the disease.

4/14/2009

34

Congenital Laryngeal Anomalies: Incidence &

ManagementManagement.

Prof.Dr. H. Abdel-Fattah,Prof.Dr. H. Abdel Fattah, Prof.Dr.N.Faseyh,

Dr. A.Gaafar, Dr.Y.NourAlexandria - Egypt

congenital laryngeal anomalies - lectures/larynx/2...4/14/2009 1 congenital laryngeal anomalies...

Documents