EUSTACHIAN TUBE DYSFUNCTION

Dr. Prathyusha PG in ENTNarayana Medical CollegeNellore

INTRODUCTION• Anatomist Bartholomeus Eustachius in 1562,

• explained about eustachian tube

• dynamically links the middle ear and the nasopharynx.

MORE EMPHASIS• improved understanding of the • anatomy, • physiology and • pathophysiology

• Leads to ………..

Improved understanding of eustachian tube dysfunction

ANATOMY AND PHYSIOLOGY IN BRIEF

• The ET, measures approximately 31–38 mm in length

• it comprised of two portions,

• a proximal osseous portion about one-third in length contained within the temporal bone (petrosal part),

• a distal cartilaginous portion of about two-third in length.

• The bony portion is lined with cuboidal respiratory epithelium

• becomes progressively narrow until reaching the narrowest at isthmus

• fixed conduit and is always patent under normal conditions.

CARTILAGINOUS PORTION• 20 mm in length in adults and is anchored superiorly to the

basisphenoid bone.

• Ciliated pseudostratified columnar respiratory epithelium

• abundant mucin secreting goblet cells, in the inferior aspect of ET orifice

• closed at rest and opens through active muscular action

• The pharyngeal end of the tube is slit-like, vertically with an elevation called torus tubarius

• 1.25 cm behind the posterior end of inferior turbinate.

• There are four peritubal muscles,

• the tensor veli palatini (TVP),

• the levator veli palatini (LVP),

• the tensor tympani,

• the salpingopharyngeus.,

• TVP originates directly along the anterolateral membranous wall of the ET and is important for active tubal dilation as well as tubal closure

CONCEPT OF FUNCTIONAL VALVE• the mucosal surfaces of the anterolateral and posteromedial walls

are in apposition to close the lumen when in resting position.

• 8 mm long section is termed the “functional valve”

• comprised of the mucosa,

• sub mucosa,

• Ostmann fat pad,

• lateral cartilaginous lamina and

• the relaxed bulk of the tensor veli palatini muscle

OPENING OF FUNCTIONAL VALVE• occurs in two distinct phases

• Tubal dilation is initiated through palatal elevation as the LVP muscle

contracts.

• This also results in medial rotation of the torus tubarius and

the posteromedial wall of the cartilaginous Eustachian tube.

• The LVP contraction is maintained throughout the tubal dilation cycle.

• The second phase follows the contraction of the TVP, • results in a rounded ET tube lumen.

• Tubal dilation propagates from the orifice toward the isthmus of

the ET. • The closing proceeds in the opposite direction, from the isthmus to the nasopharynx.

• When closed, the valve creates an air- and water- tight seal.

LEFT ET DEPICTING THE TORUS TUBARIUS (ARROWHEAD),

ORIFICE (ARROW), ANTEROLATERAL WALL (ASTERISK).

Closed resting position Open dilated position

• the Eustachian tube dilates approximately 1.4 times per minute throughout waking hours, lasts 400 milliseconds,

• substantially decreased during sleep.

FUNCTIONS OF ET• Middle ear gas exchange

• Clearance of the middle ear

• Protection of middle ear

MIDDLE EAR GAS EXCHANGE• gas exchange results in a progressively lower pressure within the middle ear.

• Nitrogen as part of the middle ear air diffuses very slowly

• The slower diffusion of nitrogen creates a greater percentage of nitrogen within the air of the middle ear space compared to ambient air.

• the middle ear pressure remains negative and with a higher ratio of nitrogen compared to ambient air.

• The gradient of nitrogen relative to the ambient air is believed to play an important role in the regulation of pressure in ET dysfunction. (lo t of studies and

research and research going on…!)

• The Eustachian tube actively dilates by

• voluntary actions such as yawning and swallowing,

• involuntary actions of autonomic reflex stimulation

• due to alterations in gas composition and pressure that

are detected by baroreceptors and chemo receptors

CLEARANCE OF THE MIDDLE EAR

• The distal cartilaginous portion actively moves secretions, fluids and debris toward the nasopharyngeal opening of the tube through mucociliary transport.

• However, in the presence of extremely viscous secretions mucociliary clearance can be hindered

. Surfactants in the ET may serve to help reduce surface tension within the lumen,

• aiding mucociliary clearance,

• tubal dilation,

• exchange of gases across the mucosal barrier.

• muscular pumping action during the tubal closing process

that additionally facilitates tubal clearance.

• In the closing process after dilation as the ET closes in a proximal-to-distal direction,

• creates an expelling force from the relaxing cartilage and peritubal muscles

PROTECTION OF MIDDLE EAR

• The valve of the ET protects the middle ear against the reflux of sounds and material from the nasopharynx

• the existing air pressure within the middle ear and mastoid cavity provides a gas cushion that further inhibits the reflux of material from reaching the middle ear

ETIOLOGY

• Inflammation due to infection or allergy in upper respiratory tract

• Children with frequent URTI

• reflux disease in younger children

• exposure to tobacco smoke (Smoke impairs the mucociliary function)

• primary ciliary disorders (Increased viscosity)

• Pregnancy and OCPs (high progesterone states)

• Anatomical obstruction of the ET from neoplasms (less common).

• adenoid hypertrophy that encroaches on the torus tubarius causes mechanical obstruction.

• The contraction of pharyngeal constrictors during swallowing can press an enlarged adenoid into the torus tubarius and force it anteriorly to close the tubal orifice instead of dilating it open

RIGHT EUSTACHIAN TUBE WITH INFLAMED ADENOID IN UPPER CORNER

Closed resting position Attempt to open the tube by swallowing

DYNAMIC CAUSES OF ET

• dilatory dysfunction may be due to hypoactive, hyperactive or uncoordinated contraction of TVP or LVP muscles.

• Hypoactive TVP muscle causes decrease in anterolateral wall dilatory movement.

• reduces lateral excursion of the anterolateral wall in the final step of dilation.

• Excessive contractions have been observed in both TVP

and LVP muscles

• This leads to a bulky mass effect thereby paradoxically impairing the valve dilation

RARE CAUSES • A structural compromise or defect of the ET • familial predisposition for tubal dysfunction • cleft lip or palates,

• craniofacial anomalies.

• Primary disorders of the mucosa or submucosa such as

• Wegener’s disease,

• Samter’s triad

• granulomatous diseases are less common etiologies.

PATHOLOGY OF EUSTACHIAN TUBE DYSFUNCTION

• Endoscopy of the ET in patients with ET dysfunction have identifiable pathology within the cartilaginous portion.

• Insufficient dilation of the Eustachian tube (dilatory dysfunction (most common type )

• patulous Eustachian tube, the failure of proper closure of the tubal valve next common

• Dilatory dysfunction is most commonly due to insufficient dilation rather than true blockage of the lumen.

• The most common finding in is mucosal inflammation within the cartilaginous ET.

• The inflammation involves the lymphoid tissues in the torus tubarius and the glandular mucosal surfaces of the nasopharyngeal orifice.

• The mucosa closer to the isthmus is typically much less inflamed.

INFLAMED TORUS TUBARIUS AND LYMPHOID HYPERPLASIA

STUDY • mucosal edema near the orifice was found in 83%

• reduced anterolateral wall movement of the ET due to the thickness of the inflamed mucosa in 74%

• Adjacent inflammation in the adenoid is common. (values not available)

TESTS FOR ET PATENCY• 1. Valsalva test

• 2. Politzer test • 3. Catheterisation

• 4. Toynbee's test

TESTS• 5. Tympanometry

• 6. Radiological test

• 7. Saccharine or methylene blue test

• 8. Sonotubometry

MEDICAL TREATMENT FOR ET DILATORY DYSFUNCTION

• Mucosal disease is the most common cause of dilatory dysfunction.

• Identifying the underlying etiology • Allergies are a common cause of dilatory dysfunction. • Allergen avoidance, • Oral or nasal antihistamines, • nasal topical steroid drops and sprays• mast cell stabilizer sprays,• leukotriene inhibitors,

• Recurrent nasal or sinus infections should be maximally treated as indicated.

• Granulomatous diseases usually require immunosuppressant therapy

• Laryngopharyngeal reflux should be treated with

• behavioral and dietary modifications

• anti-reflux medications.

• fundoplication surgery (severe cases )

• True anatomical obstruction requires contrast

enhanced imaging to determine the etiology.

• Identified benign or malignant lesions may be indicated for excision as the definitive therapy

ADENOIDECTOMY• Adenoidectomy in dilatory dysfunction especially if the hypertrophied adenoid tissue reaches the torus tubarius endures good results.

• Endoscopic-assisted adenoidectomy permits more complete removal of the tissue encroaching the torus.

• It further allows for some debulking of the hyperplastic tissue of the torus, if considered necessary.

• Persistence of dilatory dysfunction despite optimal medicaland surgical management indicates……..

• IRREVERSIBLE MUCOSAL INJURY

OPTIONS LEFT• Tympanostomy tubes

• Corticosteriods

• Eustachian tuboplasty

• Balloon dilation

TYMPANOSTOMY TUBE• tympanostomy tube alleviate the negative pressure relieve TM retraction, effusion and atelectasis.

• Effusion or inflammation that continues despite tubes in place may indicate a primary mucosal disorder.

• Thick glue-like effusions are associated with up regulation of the MUC genes causing increased protein production.

• These conditions will frequently respond to oral or topical corticosteroids.

EUSTACHIAN TUBOPLASTY

• In recent years, Eustachian tuboplasty is a safe and possibly effective surgical option patients with dilatory dysfunction. • Candidates for Eustachian tuboplasty are

• chronic tubal dilatory dysfunction despite maximum medical therapy. • Recur rent tube placements due to either extrusion or recurrence of symptoms

RATIONALE OF TUBOPLASTY

• Dilation of the lumen by surgical debulking facilitates the dilatory action of the TVP muscle

• removes irreversibly diseased mucosal tissue allowing for regrowth of healthy mucosa.

• Submucosal tissue and cartilage within the valve region may be removed, but the mucosa is conserved to prevent synechiae.

• This is accomplished using either a laser or microdebrider

• inflamed soft tissue and cartilage removal as indicated from the luminal side of the posteromedial wall, beginning from the leading edge of the torus tubarius and extending up to or into the valve.

• avoid injury to the anterolateral wall (TVP IS PRESENT)

• avoid contact with the internal carotid artery.

LASER TUBOPLASTY RT.ET

edematous torus tubarius KTP laser, fiber mucosa

and soft tissue is removed

A portion of cartilage that protruded into the lumen has been divided with scissors, and cup forceps are used for removal

The completed operative field with tmucosal and submucosal defect. An olive tipped curved suction is retracting the torus tubarius medially for exposure

PRE AND POSTOP LEFT ET LASEREUSTACHIAN TUBOPLASTY.

Preoperative, resting position

Preoperative, dilated position

POST OP LASERResting position;the torus shows a scaphoid defect on the luminal surface; the inflammation is markedly reduced;

Postoperative, dilated position; the lumen is nowexposed with dilatory effort

• In the senior author’s two-year follow-up study of Eustachian tuboplasty

• 38% of 13 adults had remission of their effusion.

• overall improvement rate of 68%.

• There were no significant complications.

FAILURE OF LASER TUBOPLASTY

• correlated with the presence of allergies or laryngopharyngeal reflux.

• need to continue to manage any underlying conditions

postoperatively.

BALLOON TUBOPLASTY• Most recently balloon dilation of the cartilaginous ET

has• feasibility, • safety and • early clinical application.

• Cadaveric studies using balloon dilation catheters for tubal dilation proved to be effective with minimal risks.

ADVERSE EVENTS • minor tears in the mucosal lumen• Failure to rotate the torus medially before inserting the catheter results in mucosal laceration with bleeding

or a false passage into the submucosal tissues

• neither osseous cartilaginous fracture nor trauma to the

internal carotid

BALLOON DILATION OF A LT. ET

Preoperative resting position of the auditory tube withedema and inflammation of the torus tubarius

A guide catheter is inserted into thetubal lumen

The balloon catheter inserted up to 16 mm depth,and inflated to 12 atm for two minutes

widened lumen and minimal mucosal lacerations are appreciated

PATULOUS EUSTACHIAN TUBE DYSFUNCTION

• refers to persistent patency of the tubal lumen. • Air and sound pass unrestricted between the nasopharynx and the middle ear space.

• disturbing amplified perception of one’s own voice and nasal breathing sounds (autophony), • sensation of aural fullness, • otalgia.

• Worsens with nasal steroids or decongestants

ETIOLOGY

• a dramatic and substantial weight loss

• during post-pregnancy,

• cachectic diseases,

• dietary weight loss

• bariatric surgery.

• one-third have an associated systemic rheumatologic disorder

• remaining third are idiopathic.

ENDOSCOPIC EXAMINATION

• loss of convex bulge in anterolateral wall

• Underdeveloped lateral cartilaginous lamina

• less Ostmann’s fat

• Exercise frequently initiates or exacerbates symptoms.

• They tend to abate in the supine or head dependent positions.

OTOSCOPY • excursions of the tympanic membrane during nasal

breathing while the opposite nostril is held shut.

IMPEDANCE TYMPANOMETRY• It shows ventilatory fluctuations• sawtooth-like perturbations of the baseline• tympanogram tracing.

• The breathing is performed irregularly not to confuse the

tracing with the regular sawtooth waveforms that can occur from intracranial pulsations.

MEDICAL MANAGEMENT• restoration of the healthy humidified mucosa and competence

• Discontinuation of decongestants • Discontinue topical nasal corticosteroid, • increase their fluid intake• adding nasal saline drops or irrigations to improve hydration of the mucosa.

THERAPEUTIC OPTIONS• saturated solution of potassium iodide (SSKI),

enhances the viscosity of the mucus. • boric acid, salicylic acid powder, silver nitrate, nitrate acid and phenol cause tissue inflammation and thus increased mucus production.

• The off-label use of Premarin or depo-estradiol estrogens

cause localized mucosal hypertrophy and thus temporary closure of the open Eustachian tube.

SURGICAL TREATMENT OF PATULOUS EUSTACHIAN TUBE DYSFUNCTION

• with tympanostomy tube placement is effective for • aural fullness and tympanic membrane excursions.

• To alleviate autophony, complete occlusion of the • Eustachian tube lumen can be considered.

• Occluding them with bone wax

• occluding it with a fat graft.

• Alternatively, autologous cartilage

• An intravenous catheter filled with bone wax can be employed in this off-label application.

LEFT PATULOUS ET SHOWING INSERTION OF IV CATHETER

The left tubal orifice before intervention

The catheter is housed in an introducer tool. It is being positioned into the tubal orifice

The catheter is firmly wedged into the bony-cartilaginous isthmus

The catheter is in the final position at the level of the torus tubarius

CONCLUSION 1• Proper function of the ET is essential for

• aeration,

• clearance • protection of the middle ear space.

CONCLUSION 2• Disorders of the ET commonly have identifiable

pathology within the cartilaginous portion of the tube.

CONCLUSION 3• In the majority of cases, these can be managed

conservatively.

• In selected cases, surgical intervention for

Eustachian tube Disorders is now possible.

CONCLUSION 4• However, more data from controlled clinical trials are needed to determine the long-term benefit of the procedures.

• Additionally, basic science investigations are required to better understand the etiology of Eustachian tube dysfunction as well as the impact of the surgical therapies.

BIBILIOGRAPHY• Recent Advances in Otolaryngology Head and Neck Surgery , Anil K Lalwani md JAYPEE BROTHERS MEDICAL PUBLISHERS (P) LTD 2012

• Scott and Brown Otolaryngology and Head and Neck Surgery, 7th Edition Miachel Gleeson

• Otologic Surgery 3rd edition Brackman and Shelton, Saunders, an imprint of Elsevier publications 2010.

• Diseases of Ear, Nose, and Throat, 5th edition, P.L.Dhingra, Elsevier publications 2012.