Subglottic Stenosis

Subglottic StenosisSubglottic Stenosis

Deborah P. Wilson, M.D.Deborah P. Wilson, M.D.

Norman Friedman, M.D.Norman Friedman, M.D.

April 14, 1999April 14, 1999

Basic Science ReviewBasic Science ReviewWound HealingWound Healing

involves three temporally involves three temporally overlapping stagesoverlapping stages

inflammatory phase, proliferative inflammatory phase, proliferative phase and contraction or phase and contraction or remodeling phaseremodeling phase

Inflammatory PhaseInflammatory Phase

involves vascular constriction and involves vascular constriction and then dilationthen dilation

coagulation and complement coagulation and complement cascade is activatedcascade is activated

PMNs enter wound at 6 hrs post PMNs enter wound at 6 hrs post injuryinjury

PMNs function to phagocytize PMNs function to phagocytize debris and bacteria from wounddebris and bacteria from wound


Helper T cells are necessary for Helper T cells are necessary for wound healingwound healing

Macrophages enter wound within Macrophages enter wound within 48 hrs48 hrs

only cells that can fxn at low 02 only cells that can fxn at low 02 levelslevels

Macrophages are essential to Macrophages are essential to wound healing wound healing


growth factors are major regulators growth factors are major regulators of healingof healing

they interact with cellular receptors they interact with cellular receptors to modify cell activitiesto modify cell activities

IL-1 directly stimulates fibroblast IL-1 directly stimulates fibroblast activity including proliferation and activity including proliferation and collagen synthesiscollagen synthesis

IL-2 is produced by helper T cellsIL-2 is produced by helper T cells


structural components essential to structural components essential to wound healing include fibronectin, wound healing include fibronectin, collagens, glycoproteins and collagens, glycoproteins and glycosaminoglycansglycosaminoglycans

several types of collagen are found several types of collagen are found in the healing woundin the healing wound

Proliferative PhaseProliferative Phase

lasts 10-14 dayslasts 10-14 days begins with re-epithelizationbegins with re-epithelization the epithelial cells 1-2mm from the wound the epithelial cells 1-2mm from the wound

edge undergo phenotypic changesedge undergo phenotypic changes cell replication rate increases 17 foldcell replication rate increases 17 fold epithelial cell migration is dependent on epithelial cell migration is dependent on

local humidity and oxygenationlocal humidity and oxygenation epithelial cells migrate much quicker when epithelial cells migrate much quicker when

the wound is moist and occludedthe wound is moist and occluded

Proliferative PhaseProliferative Phase Neovascularization is the next part of the Neovascularization is the next part of the

proliferaitve phaseproliferaitve phase macrophages secrete angiogenic factorsmacrophages secrete angiogenic factors endothelial migration results in capillary bud endothelial migration results in capillary bud

formationformation collagen deposition begins when fibroblasts collagen deposition begins when fibroblasts

enter the wound at 48-72hrsenter the wound at 48-72hrs the collection of fibroblasts, inflammatory the collection of fibroblasts, inflammatory

cells and capillary buds is referred to as cells and capillary buds is referred to as granulation tissuegranulation tissue

Wound Contraction and Wound Contraction and RemodelingRemodeling

Begins 6-7 days after injury and is Begins 6-7 days after injury and is maximal for 10 daysmaximal for 10 days

eventually decreases the defect by 40-eventually decreases the defect by 40-60%60%

skin grafts and flaps can reduce skin grafts and flaps can reduce contraction by 50-70%contraction by 50-70%

remodeling results in a scar with as remodeling results in a scar with as much as 80% of the skin’s original much as 80% of the skin’s original tensile strengthtensile strength

Subglottic StenosisSubglottic Stenosis

Congenital or acquired narrowing of Congenital or acquired narrowing of the subglottic airwaythe subglottic airway

third most common congenital third most common congenital airway problemairway problem

Otolaryngologist must be an expert Otolaryngologist must be an expert at diagnosis and managementat diagnosis and management

can occur in adults and childrencan occur in adults and children

AnatomyAnatomy

infant larynx differs in size and position infant larynx differs in size and position when compared to adult larynxwhen compared to adult larynx

the narrowest portion of the adult airway the narrowest portion of the adult airway is the glottic aperture while in the infant is the glottic aperture while in the infant it is the subglottisit is the subglottis

the infant larynx is higher in the neckthe infant larynx is higher in the neck the structures of the infant airway are the structures of the infant airway are

more pliable and less fibrous making it more pliable and less fibrous making it susceptible to narrowing from edemasusceptible to narrowing from edema

EmbryologyEmbryology

Respiratory system is outgrowth of primitive Respiratory system is outgrowth of primitive pharynxpharynx

begins at 26 days after conceptionbegins at 26 days after conception laryngotracheal diverticulum becomes separated laryngotracheal diverticulum becomes separated

from foregut by tracheoesophageal foldsfrom foregut by tracheoesophageal folds tracheoesophageal folds fuse to form tracheoesophageal folds fuse to form

tracheoesophageal septumtracheoesophageal septum septum divides foregut into ventral septum divides foregut into ventral

laryngotracheal tube and a dorsal esophaguslaryngotracheal tube and a dorsal esophagus failure of TE folds to fuse can cause TE fistulafailure of TE folds to fuse can cause TE fistula


Larynx develops from 4th and 5th branchial Larynx develops from 4th and 5th branchial archesarches

laryngotracheal opening lies between these two laryngotracheal opening lies between these two archesarches

laryngeal aditus becomes T shaped by growth of laryngeal aditus becomes T shaped by growth of three massesthree masses

1st mass=hypopharyngeal eminence which 1st mass=hypopharyngeal eminence which eventually becomes the epiglottiseventually becomes the epiglottis

2nd and 3rd masses are arytenoid masses. As 2nd and 3rd masses are arytenoid masses. As these masses grow between 5-7th weeks, these masses grow between 5-7th weeks, laryngeal lumen is obliteratedlaryngeal lumen is obliterated


recanalization occurs in 10th weekrecanalization occurs in 10th week failure to recanalize = atresia or stenosis of failure to recanalize = atresia or stenosis of

larynxlarynx arytenoid masses separated by notch which arytenoid masses separated by notch which

eventually becomes obliterated. eventually becomes obliterated. failure to obliterate can result in posterior failure to obliterate can result in posterior

laryngeal cleft which can cause severe laryngeal cleft which can cause severe aspiration in the newbornaspiration in the newborn

Congenital Subglottic Congenital Subglottic StenosisStenosis

Thought to be secondary to failure of Thought to be secondary to failure of laryngeal lumen to recanalizelaryngeal lumen to recanalize

defined as subglottic diameter less than defined as subglottic diameter less than 4.0mm in full term infant4.0mm in full term infant

normal full term newborn subglottic normal full term newborn subglottic diameter = 4.5-5.5diameter = 4.5-5.5

premature infant subglottic diameter = premature infant subglottic diameter = 3.5mm. If less than 3.5mm in premie = 3.5mm. If less than 3.5mm in premie = subglottic stenosissubglottic stenosis


Considered congenital if no previous Considered congenital if no previous history of intubation or traumahistory of intubation or trauma

divided into membranous or cartilaginous divided into membranous or cartilaginous typestypes

membranous is soft-tissue thickening membranous is soft-tissue thickening from fibrous connective tissue or from fibrous connective tissue or hyperplastic submucous glandshyperplastic submucous glands

membranous may also involve the vocal membranous may also involve the vocal folds folds


Cartilaginous usually results from Cartilaginous usually results from thickened or malformed cricoidthickened or malformed cricoid

usually forms large anterior subglottic usually forms large anterior subglottic shelf leaving only small airway shelf leaving only small airway posteriorlyposteriorly

can be due to an elliptical shaped can be due to an elliptical shaped cricoidcricoid

membranous type usually less severe membranous type usually less severe than cartilaginousthan cartilaginous


severity depends on degree of severity depends on degree of subglottic narrowingsubglottic narrowing

symptoms can range from mild symptoms can range from mild with picture of recurrent croup to with picture of recurrent croup to severe with respiratory distress at severe with respiratory distress at deliverydelivery

often associated with other often associated with other congenital anomaliescongenital anomalies

Acquired Subglottic Acquired Subglottic StenosisStenosis

Numerous causes including intubation, Numerous causes including intubation, trauma, infection/inflammation, trauma, infection/inflammation, thermal or caustic injuriesthermal or caustic injuries

most common cause is endotracheal most common cause is endotracheal intubation intubation

since more very premature infants are since more very premature infants are surviving, incidence of acquired surviving, incidence of acquired subglottic stenosis has increasedsubglottic stenosis has increased


Reported incidence in intubated patients Reported incidence in intubated patients = 1-8%= 1-8%

pathogenesis not completely understoodpathogenesis not completely understood one theory includes mucosal pressure one theory includes mucosal pressure

leading to ulceration leading to chondritis leading to ulceration leading to chondritis and finally deposition of fibrous materialand finally deposition of fibrous material

less results in weakened cartilage less results in weakened cartilage framework and firm scarframework and firm scar


risk factors in neonates include risk factors in neonates include prolonged intubation, size of prolonged intubation, size of endotracheal tube, increased motion endotracheal tube, increased motion of tube, repeated intubations, birth of tube, repeated intubations, birth weight less than 1500g, infection, weight less than 1500g, infection, presence of NG tubes and GERDpresence of NG tubes and GERD

many feel most important factor is many feel most important factor is length of intubationlength of intubation


There is no “safe” period for There is no “safe” period for intubationintubation

premies tolerate intubation better premies tolerate intubation better than adults due to more yielding than adults due to more yielding and pliable tissuesand pliable tissues

it has been suggested that it has been suggested that tracheotomy be considered after tracheotomy be considered after 50 days of intubation in neonates50 days of intubation in neonates


Ideal endotracheal tube size allows Ideal endotracheal tube size allows air leak at pressure of 20cm H2Oair leak at pressure of 20cm H2O

absence of audible air leak is absence of audible air leak is indicative of excessively large tubeindicative of excessively large tube

tube motion can cause abrasion tube motion can cause abrasion and trauma to mucosaand trauma to mucosa

tube should be carefully secured tube should be carefully secured and patient adequately sedatedand patient adequately sedated


Repeated intubations should be Repeated intubations should be minimized. No routine tube changes.minimized. No routine tube changes.

Better education and care of Better education and care of intubated infants has lead to a intubated infants has lead to a decrease in incidence of acquired decrease in incidence of acquired subglottic stenosissubglottic stenosis

routine use of surfactant also appears routine use of surfactant also appears to have lowered the incidenceto have lowered the incidence

DiagnosisDiagnosis

Typically present with stridor and Typically present with stridor and respiratory distressrespiratory distress

stridor is biphasicstridor is biphasic diagnosis begins with complete historydiagnosis begins with complete history question parents about: duration, question parents about: duration,

progression, hx of prematurity, birth progression, hx of prematurity, birth trauma, hx of intubation,feeding trauma, hx of intubation,feeding problems, change in voice or cry, recent problems, change in voice or cry, recent trauma or foreign body exposure trauma or foreign body exposure

DiagnosisDiagnosis

Examine child at rest and when agitatedExamine child at rest and when agitated auscultate over nose, mouth, neck and auscultate over nose, mouth, neck and

chest chest quality of child’s voice should be notedquality of child’s voice should be noted flexible fiberoptic examination should be flexible fiberoptic examination should be

performedperformed special attention paid to vocal cord motionspecial attention paid to vocal cord motion subglottis can sometimes be seen below subglottis can sometimes be seen below

the cords the cords

DiagnosisDiagnosis Radiographic evaluation includes AP and Radiographic evaluation includes AP and

lateral views of necklateral views of neck narrowed subglottic airway suggests narrowed subglottic airway suggests

stenosis or croupstenosis or croup airway fluoro can be helpfulairway fluoro can be helpful Ba swallow can help r/o vascular Ba swallow can help r/o vascular

compressioncompression CT has not been helpful is assessing CT has not been helpful is assessing

pediatric airwaypediatric airway

DiagnosisDiagnosis

Gold standard remains rigid Gold standard remains rigid endoscopy under GAendoscopy under GA

Magnification with Hopkins telescopes Magnification with Hopkins telescopes very helpful in defining pathologyvery helpful in defining pathology

palpation of cricoarytenoid joints imptpalpation of cricoarytenoid joints impt wait few minutes after removing ET wait few minutes after removing ET

tube to look for edema that tube was tube to look for edema that tube was stentingstenting

DiagnosisDiagnosis

No universal classification systemNo universal classification system in past, measurements were done in past, measurements were done

subjectively or using various subjectively or using various instrumentsinstruments

most commonly used system today is most commonly used system today is Cotton’s Cotton’s

percentage of obstruction and anatomic percentage of obstruction and anatomic location were assigned grade I-IV based location were assigned grade I-IV based on perceived percentage of obstructionon perceived percentage of obstruction

DiagnosisDiagnosis

This system is dependent on skilled This system is dependent on skilled judgementjudgement

Myer, Conner and Cotton have proposed Myer, Conner and Cotton have proposed system based on standardized system based on standardized endotracheal tube sizesendotracheal tube sizes

the ET tube that will pass thru the the ET tube that will pass thru the lumen and has normal leak pressures is lumen and has normal leak pressures is compared to the expected age-compared to the expected age-appropriate tube sizeappropriate tube size

DiagnosisDiagnosis

The maximum percentage of The maximum percentage of airway obstruction is determined airway obstruction is determined and assigned a grade:and assigned a grade:

Grade I Grade I <50% obstruction<50% obstruction Grade II Grade II 51-70% obstruction51-70% obstruction Grade IIIGrade III 71-99% obstruction71-99% obstruction Grade IVGrade IV no detectable lumenno detectable lumen

ManagementManagement

begins with preventionbegins with prevention control of risk factors is essentialcontrol of risk factors is essential although controversial, many feel that although controversial, many feel that

significant GERD should be treated prior significant GERD should be treated prior to any surgical interventionto any surgical intervention

Halstead recently demonstrated that Halstead recently demonstrated that significant GERD is an important cofactor significant GERD is an important cofactor in many pediatric airway ds, particularly in many pediatric airway ds, particularly subglottic stenosissubglottic stenosis


Acquired subglottic stenosis is Acquired subglottic stenosis is typically more severe than typically more severe than congenital and more likely to congenital and more likely to require surgical interventionrequire surgical intervention

many of these patients will require many of these patients will require a tracheotomy while awaiting a tracheotomy while awaiting definitive therapydefinitive therapy

ManagementManagement Mild stenosis (Grades I and II) can usually Mild stenosis (Grades I and II) can usually

be treated with endoscopic techniques be treated with endoscopic techniques such as dilation and CO2 laser resectionsuch as dilation and CO2 laser resection

factors associated with failure include: factors associated with failure include: previous attempts at endoscopic repair, previous attempts at endoscopic repair, loss of cartilaginous support, exposure of loss of cartilaginous support, exposure of cartilage during laser resection, bacterial cartilage during laser resection, bacterial infection, posterior inlet scarring, glottic infection, posterior inlet scarring, glottic involvement, vertical scar length of > 1cminvolvement, vertical scar length of > 1cm


Endoscopic dilation has had Endoscopic dilation has had disappointing resultsdisappointing results

Endoscopic laser resection for Endoscopic laser resection for Grades I and II stenosis have Grades I and II stenosis have success rates ranging from 66-80%success rates ranging from 66-80%


More severe stenosis (Grades III More severe stenosis (Grades III and IV) usually require open and IV) usually require open surgical approachsurgical approach

contraindications include: inability contraindications include: inability to tolerate GA, persistent need for to tolerate GA, persistent need for tracheotomy, significant GERD, an tracheotomy, significant GERD, an ICU not equipped to handle the ICU not equipped to handle the post-operative carepost-operative care


Some of more popular procedures Some of more popular procedures include: anterior cricoid split, include: anterior cricoid split, laryngotracheoplasty (either laryngotracheoplasty (either stented or one-stage), and end-to-stented or one-stage), and end-to-end anastomosisend anastomosis

anterior cricoid split usually used in anterior cricoid split usually used in neonate who has failed extubation neonate who has failed extubation instead of doing tracheotomy instead of doing tracheotomy

Anterior Cricoid SplitAnterior Cricoid Split

Criteria include: extubation failure on Criteria include: extubation failure on two occasions due to laryngeal two occasions due to laryngeal pathology, weight >1500g, no assisted pathology, weight >1500g, no assisted ventilation 10 days prior, O2 ventilation 10 days prior, O2 requirements <30%, no CHF one month requirements <30%, no CHF one month prior, no infectionprior, no infection

performed after DL and B ahs performed after DL and B ahs confirmed diagnosisconfirmed diagnosis

all other airway pathology must be r/oall other airway pathology must be r/o

Anterior Cricoid SplitAnterior Cricoid Split

Vertical incision thru cricoid, first Vertical incision thru cricoid, first two tracheal rings and lower thyroid two tracheal rings and lower thyroid cartilagecartilage

stay sutures on either sidestay sutures on either side drain placementdrain placement remains in ICU intubated and remains in ICU intubated and

sedated for 7-14 days based on sedated for 7-14 days based on infant’s weightinfant’s weight

Laryngotracheal Laryngotracheal ExpansionExpansion

Involves scar division with distraction of Involves scar division with distraction of edges with interposition of graft to widen edges with interposition of graft to widen the airwaythe airway

several techniques depending on severity several techniques depending on severity and location of stenosisand location of stenosis

laryngotracheoplasty (LTP) can be done laryngotracheoplasty (LTP) can be done in two stages with a stent or a single in two stages with a stent or a single stage using the ET tube as a stentstage using the ET tube as a stent

One-stage LTP is gaining popularityOne-stage LTP is gaining popularity

Laryngotracheal Laryngotracheal ExpansionExpansion

Anterior laryngofissure with anterior lumen Anterior laryngofissure with anterior lumen augmentation - good for stenosis that does augmentation - good for stenosis that does not involve the glottis and has good not involve the glottis and has good cartilage supportcartilage support

Laryngofissure with division of posterior Laryngofissure with division of posterior cricoid - used in pts with glottic cricoid - used in pts with glottic involvement or significant cricoid deformityinvolvement or significant cricoid deformity

Laryngofissure with anterior and posterior Laryngofissure with anterior and posterior grafting - as above but significant posterior grafting - as above but significant posterior stenosisstenosis

End-to-End AnastomosisEnd-to-End Anastomosis

Indicated if severe cricoid deformity Indicated if severe cricoid deformity causing grafting likely to failcausing grafting likely to fail

most say there must be 10mm of most say there must be 10mm of normal airway below glottis but Cotton normal airway below glottis but Cotton says can resect up to vocal folds but says can resect up to vocal folds but expect prolonged edemaexpect prolonged edema

technically difficult due to close technically difficult due to close proximity of vocal folds and risk to proximity of vocal folds and risk to recurrent nervesrecurrent nerves

End-to-End AnastomosisEnd-to-End Anastomosis

Stenosis <4cm can be resected with Stenosis <4cm can be resected with laryngeal release and cervical tracheal laryngeal release and cervical tracheal mobilizationmobilization

stenting is not requiredstenting is not required can be performed with a tracheostomy can be performed with a tracheostomy

tube in place or as a single stagetube in place or as a single stage Monnier reports good success with high Monnier reports good success with high

grade lesions - decannulation rate of grade lesions - decannulation rate of 93%93%

Post-operative CarePost-operative Care

Require specialized care in ICURequire specialized care in ICU if two-staged, hospitalization stay is if two-staged, hospitalization stay is

shortershorter if single-staged LTP or ACS, stay if single-staged LTP or ACS, stay

intubated in ICU for 7-14 daysintubated in ICU for 7-14 days requires heavy sedation with or without requires heavy sedation with or without

paralysisparalysis extubation done when adequate airleak extubation done when adequate airleak

or after certain periodor after certain period

ComplicationsComplications

Infrequent but can include (in decreasing Infrequent but can include (in decreasing order of frequency): atelectasis, order of frequency): atelectasis, pneumonia, malpositioned ET tube, pneumonia, malpositioned ET tube, accidental extubation, occluded ET tube, accidental extubation, occluded ET tube, wound infection, granulation tissue, TC wound infection, granulation tissue, TC fistulafistula

Complications specific to prolonged Complications specific to prolonged sedation required for single-stage sedation required for single-stage procedures include narcotic withdrawal procedures include narcotic withdrawal and transient muscle paralysisand transient muscle paralysis

OutcomesOutcomes

The goal is decannulationThe goal is decannulation success is dependent on cause, success is dependent on cause,

number of previous failed number of previous failed attempts, status of the remainder attempts, status of the remainder of airway and severity of stenosisof airway and severity of stenosis

Cotton reports overall success Cotton reports overall success =92%, Grade II = 97% Grade III = =92%, Grade II = 97% Grade III = 91% and Grade IV = 72%91% and Grade IV = 72%

OutcomesOutcomes Many authors report that a functional voice is Many authors report that a functional voice is

restored in most patientsrestored in most patients MacArthur reports on 12 pediatric patients MacArthur reports on 12 pediatric patients

who under went LTRwho under went LTR 78% had altered anatomy78% had altered anatomy 44% had altered function44% had altered function 100% had decreased voice quality100% had decreased voice quality conclusion = children with high grade conclusion = children with high grade

stenosis are at risk for poor voice outcome stenosis are at risk for poor voice outcome after LTR after LTR

Subglottic Stenosis

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