Normal laryngeal functions are :

•phonation,

•ventilation,

•airway protection.

Failure of the laryngeal valve to achieve aerodigestive

separation during swallowing results in aspiration.

INTRODUCTION

•The lower respiratory tract is protected from soilage by

the glottis & other laryngeal protective mechanisms.

Clearance of material, either aspirated or inhaled, is

provided by mucous glands & cilia in the tracheobronchial

tree that trap debris & move it to the glottis, to be

expelled.

LARYNGEAL ANATOMY & PHYSIOLOGYLARYNGEAL ANATOMY & PHYSIOLOGYLARYNGEAL ANATOMY & PHYSIOLOGYLARYNGEAL ANATOMY & PHYSIOLOGY

The supraglottic larynx is designed to protect the laryngeal

inlet by diverting the swallowed bolus laterally into the

pyriform sinuses.

The shield-like epiglottis, the aryepigottic folds & the

lateral pharyngeal walls form “gutters” of the

laryngopharynx, which direct the flow around the laryngeal

introitus towards the posterior pharyngeal wall &

postcricoid region.

Reflex-coordinated relaxation of the cricopharyngeal

sphincter & contraction of the constrictor muscles

following laryngeal closure then move the bolus through

the hypopharynx into the esophagus.

LARYNGEAL ANATOMY & PHYSIOLOGYLARYNGEAL ANATOMY & PHYSIOLOGYLARYNGEAL ANATOMY & PHYSIOLOGYLARYNGEAL ANATOMY & PHYSIOLOGY

•The laryngeal inlet, formed by the epiglottis, aryepiglottic folds, &

arythenoids constitutes the first 1/3 of a sphincter system that

reflexively close during normal swallowing.

•The 2nd 1/3 , at the level of the false V.C.

•The true V.C. form the 3rd 1/3 & most effective..

•The protective function of the larynx is predominantly reflexive &

involuntary.

LARYNGEAL ANATOMY & PHYSIOLOGYLARYNGEAL ANATOMY & PHYSIOLOGYLARYNGEAL ANATOMY & PHYSIOLOGYLARYNGEAL ANATOMY & PHYSIOLOGY

•The afferent of sensory nerve fibers of the larynx travel in the internal branch of the SLN, providing ipsilateral innervation to the supraglottic structures.

•Innervation below this level is provided by the ipsilateral RLN.

•Afferent impulses pass up the vagus nerve to the nodose ganglion & from there to the tractus solitarius.

•Efferent motor innervation of the larynx is mediated via the nucleus ambigus ( motor nucleus of X) for both reflex & voluntary functions.

•The RLN innervates all intrinsic muscles of the larynx except the cricoithyroid muscle, which receives its innervation via the external branch of the SNL.

•Innervation is unilateral except for the interarythenoid muscle, which receives bilateral input.

LARYNGEAL ANATOMY & PHYSIOLOGYLARYNGEAL ANATOMY & PHYSIOLOGYLARYNGEAL ANATOMY & PHYSIOLOGYLARYNGEAL ANATOMY & PHYSIOLOGY

Oral Stage:is the initial act in swallowing.

•Considered the only voluntary phase.

•The tongue positions the bolus against the hard palate in preparation for the swallow.

•These afferent impulses are carried by IX & X to the swallowing center located in the reticular formation of the medulla, which initiates the entirely reflexive:

Pharyngeal stage:

•As the bolus passes through the faucial arch, there is spontaneous & reflex elevation & approximation of the velum to the posterior pharyngeal wall.

NORMAL SWALLOWING PHYSIOLOGYNORMAL SWALLOWING PHYSIOLOGYNORMAL SWALLOWING PHYSIOLOGYNORMAL SWALLOWING PHYSIOLOGY

Posterior movement of the tongue base & contraction of the

suprahyoid musculature results in the laryngeal elevation which, in

turn, displaces the epiglottis posteriorly, overlapping and protecting the

glottis.

As the peristaltic wave reaches the cricopharyngeal region there is

reflex relaxation of the cricopharyngeal sphincter that facilitates

passage of the bolus into the esophagus.

Esophageal stage:

primary peristaltic waves carry the bolus in an uninterrupted fashion

throughout the entire esophagus. Secondarily , peristaltic waves may be

initiated anywhere in the esophagus where residual food may be

present.

NORMAL SWALLOWING PHYSIOLOGYNORMAL SWALLOWING PHYSIOLOGYNORMAL SWALLOWING PHYSIOLOGYNORMAL SWALLOWING PHYSIOLOGY

•The development of a cough requires an intact

sensorineural glottic apparatus.

•Begins with a sudden deep inspiration through the widely

patent glottis. Next forceful contraction of the expiratory

muscles of respiration against the closed glottis results in

rapid increase in intrathoracic pressure. The cough is

concluded with the reflex opening of the glottis, producing

an explosive flow of air.

PHYSIOLOGY OF COUGHPHYSIOLOGY OF COUGHPHYSIOLOGY OF COUGHPHYSIOLOGY OF COUGH

1-Local structural abnormality:

•Tumor involving the tongue base, hypopharynx, supraglottic , & glottis may be associated with aspiration. Because of infiltration, mass effect, or pain.

•Similarly , aspiration is commonly encountered on the postoperative head & neck surgical unit, especially surgery of the mobile tongue if the bolus is inadequately prepared & moved into.

2-Neurologic defects:

•multiple cranial neuropathies, brain-stem insults, or neuropathy which develops in the setting of chronic cachexia…

•injury to the RLN nerve is commonly encountered---> paralysis of the ipsilateral VC in the paramedian position.

•Injury to the SLN --> paralysis of the cricopharyngeal muscle & anesthesia of the ipsilateral supraglottic larynx.

PATHOPHYSIOLOGY OF ASPIRATIONPATHOPHYSIOLOGY OF ASPIRATIONPATHOPHYSIOLOGY OF ASPIRATIONPATHOPHYSIOLOGY OF ASPIRATION

•Incidence:

10-20% aspirate of patients with GERD or achalasia.

•69% of tracheotomized patients.

•Silent aspiration in 7% of a large series of routine anesthetics.

•40% of patients with ET will ( 20% if low pressure),

Predisposing conditions:

•reduced level of consciousness,

•dysphagia,

•anatomic derangements of normal respiratory & swallowing reflexes..

•NG tube.

PATHOPHYSIOLOGY OF ASPIRATIONPATHOPHYSIOLOGY OF ASPIRATIONPATHOPHYSIOLOGY OF ASPIRATIONPATHOPHYSIOLOGY OF ASPIRATION

•Nursing, rehabilitative maneuvers,•Surgery: tracheostomy,

Cricopharyngeal myotomy (CPM),

Laryngeal suspension,

Partial cricoid resection,

Laryngeal stenting,

Vocal-Cord medialization,

Total laryngectomy,

Laryngeal closure:

-Glottic closure,

-Supraglottic closure,

-Subglottic closure.

TREATING ASPIRATIONTREATING ASPIRATIONTREATING ASPIRATIONTREATING ASPIRATION

The initial management of an ambulatory aspirating patient should include:

a-partial cricoid resection.

b-tracheostomy.

c-Instruction in supraglottic swallowing techniques

QuizQuizQuizQuiz

Chronic, intractable life-threatening aspiration in a neurologically impaired patient is best managed by:

a-supraglottic separation

b-cricopharyngeal myotomy.

c-Total laryngectomy.

d-laryngotracheal separation.

QuizQuizQuizQuiz

50 y.o. male patient is going to underwent an ablative head-and-neck surgery. What is the best technique to avoid future aspiration:

a-glottic closure.

b-laryngeal stenting.

c-Vocal cord medialization.

d-laryngeal suspension.

QuizQuizQuizQuiz

•retraining of the swallow employs the so-called

supraglottic swallowing technique. It assumes that food

particles & liquids are retained in the pharynx above

the glottis after a swallow & must be expelled or

swallowed again prior to inspiration.

•Unfortunately, this technique does not prevent

aspiration universally even in highly motivated patients,

& may not be applicable in patients with underlying

respiratory insufficiency or ineffectual cough.

Nursing, rehabilitative maneuversNursing, rehabilitative maneuversNursing, rehabilitative maneuversNursing, rehabilitative maneuvers

•Solids are often avoided because of the need for

mastication & the potential for the life-threatening

aspiration of unchewed food. It is important to recognize,

however, that the potential to aspirate is higher with thin

liquids.

•Accordingly , the use of nonpourable pureed foods is

ideal in the management of many patients.

•Upright position may reduce aspiration through reduction

of GER.

Nursing, rehabilitative maneuversNursing, rehabilitative maneuversNursing, rehabilitative maneuversNursing, rehabilitative maneuvers

•should be effective but as noninvasive as possible.

•No single procedure is perfect for all patients, so multiple

approaches have been developed .

•The presence of tracheotomy does not control aspiration,

& there is potential for exacerbating the condition. It does

however facilitate nursing care, suctioning...

SURGICAL TREATMENTSURGICAL TREATMENTSURGICAL TREATMENTSURGICAL TREATMENT

•Performance of CPM presumes that aspiration is caused

by or aggravated by slow or failed. Reflex relaxation of

the cricopharyngeal muscle during the pharyngeal plane of

swallowing.

•Through a lateral cervical approach . The actual myotomy

is done near the midline posteriorly.

•It would be prudent to perform the procedure on the side

of preexisting RLN injury. The muscle fibers of the

inferior constrictor, cricopharyngeus muscle, & upper

fibers of the esophageal sphincter are incised for a vertical

distance of 4-6cm.

CRICOPHARYNGEAL MYOTOMY (CPM)CRICOPHARYNGEAL MYOTOMY (CPM)CRICOPHARYNGEAL MYOTOMY (CPM)CRICOPHARYNGEAL MYOTOMY (CPM)

•Laryngeal suspension is usually performed as part of the

primary surgical procedure during ablative head-&-neck

surgery. Failure of elevation leaves the laryngeal inlet

exposed during the pharyngeal phase of swallowing.

When combined with inadequate or absent epiglottic

rotation and laryngeal closure, the patient is at significant

risk for aspiration.

•Nonabsorbable suture placed from the mandible to the

hyoid bone or thyroid lamina. A lateral suspension

technique that further increased th pharyngeal opening and

laryngeal protection was reported by Hillel & Goode.

LARYNGEAL SUSPENSIONLARYNGEAL SUSPENSIONLARYNGEAL SUSPENSIONLARYNGEAL SUSPENSION

•following head & neck ablative surgery.

•Phonation is preserved by the procedure but a

permanent tracheostomy is required.

•A subtotal resection of the postero-inferior one half of

the cricoid cartilage is performed together with a CPM.

•The cricoarythenoid joints and the posterior

cricoarythenoid muscle & its nerve supply are left

undisturbed.

PARTIAL CRICOID RESECTIONPARTIAL CRICOID RESECTIONPARTIAL CRICOID RESECTIONPARTIAL CRICOID RESECTION

•In severe laryngeal trauma.

•The Rliachar stent is hollow & can be modified to

permit vocalization through a one-way valve.

•Best suited for short-term utilization.

LARYNGEAL STENTINGLARYNGEAL STENTINGLARYNGEAL STENTINGLARYNGEAL STENTING

•Patients who have suffered unilateral vocal-cord paralysis

that results in symptomatic aspiration may be good

candidates for a variety of vocal cord augmentation or

medialization procedures. A variety exist:

•Advantage of Awake v/s GA procedure: the surgeon can

judge the degree of medialization.

•The material is injected lateral to the thyroarythenoid

muscle, between the vocal process and thyroid cartilage in

the middle & posterior 2/3 of the true cord. Overinjection

should be avoided.

VOCAL CORD MEDIALIZATIONVOCAL CORD MEDIALIZATIONVOCAL CORD MEDIALIZATIONVOCAL CORD MEDIALIZATION

•Control of severe aspiration by vocal cord medialization

is not likely, however, when it occurs in conjuction with

an insensate larynx. More definitive separation of the

upper airway from the digestive tract may be required in

these patients.

VOCAL CORD MEDIALIZATIONVOCAL CORD MEDIALIZATIONVOCAL CORD MEDIALIZATIONVOCAL CORD MEDIALIZATION

•for much of this century, TL has been the procedure of

choice. Still indicated in patients with poor prognoses .

•A narrow-field procedure, as described by Blitzer et al can

be performed. In this technique the strap muscles are

preserved, the mucosa over the arythenoid & cricoid is

preserved to minimize tension on the closure.

TOTAL LARYNGECTOMYTOTAL LARYNGECTOMYTOTAL LARYNGECTOMYTOTAL LARYNGECTOMY

•first described by Montgomery in 1975,

•may be performed through a midline thyrotomy. The

mucosa of the true & false cords are stripped & sutured

together.

•The potential for permanent laryngeal stenosis make this

procedure less than ideal if reversibility is feasible.

•Unreliable in the presence of mobile vocal cords.

•Normal speech is sacrified.

GLOTTIC CLOSUREGLOTTIC CLOSUREGLOTTIC CLOSUREGLOTTIC CLOSURE

•the mucosal edge of the epiglottis, arytenoids & ary-

epiglottic folds are denuded then sutured together

through an infrahyoid pharyngectomy. A small

posterior dehiscence may act as a one-way valve,

allowing phonation but not aspiration!!!

•Tracheostomy is required.•A potential risk for aspiration persists.

SUPRAGLOTTIC CLOSURESUPRAGLOTTIC CLOSURESUPRAGLOTTIC CLOSURESUPRAGLOTTIC CLOSURE

•eliminate aspiration without altering the glottis & the

supraglottis.

•2 variations: trache-osophageal diversion (TED), & the

laryngo-tracheal separation (LTS).

•Aspirated material is diverted from the trachea back

into the esophagus. The presence of a previously placed

high tracheostomy was found to preclude a

tracheoesophageal anastomosis. Therefore, the standard

Lindeman procedure was modified by oversewing the

proximal trachea as a blind pouch.

SUBGLOTTIC CLOSURESUBGLOTTIC CLOSURESUBGLOTTIC CLOSURESUBGLOTTIC CLOSURE

•Tracheoesophageal diversion & laryngotracheal

separation are as efficacious as total laryngectomy in

controlling aspiration.

•Decrease requirement for intensive skilled nursing care.

•The reversibility of the procedure is well documented.

SUBGLOTTIC CLOSURESUBGLOTTIC CLOSURESUBGLOTTIC CLOSURESUBGLOTTIC CLOSURE