Eustachian tube final PP ANATOMY,EMBRYOLOGY,FUNCTIONS,DYSFUNCTIONS TREATMENT,PATULOUS ET

Presented by : Dr Siddeshwar K G

ContentsContents

• Introduction & history

• Embryology, anatomy and physiology

• Functions

• Tests for Eustachian tube function

• Eustachian tube dysfunction

• Treatment

INTRODUCTION

Eustachian tube – Narrow channel connecting the tympanic cavity & the nasopharynx.

Understanding the role of ET in the health and disease of middle ear has tremendous impact on the management & outcome.

HistoryHistory: first described by Alcamaeon of Croton(500 B.C).Bartolomeo Eustachi Antonio Maria Valsalva

Embryology

7th week of gestation

IMPORTANT EVENTS

Osseous part - Petrous, Squamous, greater wing of Sphenoid

Cartilagenous - Two discrete chondrification center

part

Muscles - TVP, DT & Tensor tymp – Mandibular Nerve

- LVP – Vagus Nerve

Various events - Patency, elongation.

Anatomy• Bony part

• Fibrocartilagenous part and • Isthmus

Elastin Hinge • Junction of medial & lateral lamina is rich in elastin fibre

Ostmann’s Pad of Fat• Fatty tissue lateral to membranous part of cartilagenous

tube

RELATIONS WITH IMPORTANT STRUCTURES

• Osseous part – TM joint (laterally), middle cranial fossa (superiorly), ICA (medially).

• Fibrocartilagenous part - skull base (sulcus tubarius), nasopharynegal end (toras tubaris) & fossa of Rosenmuller

Muscles attached to ET

1.Tensor veli palatini (TVP)

2. Dilator tubae

3. Levator veli palatini (LVP)

4. Salpingopharyngeus

Schematic representation of muscles attachment

Representation of muscle at various plane

Histology• Bony part - low cuboidal ciliated

epithilium• Cartilagenous - pseudostratified part ciliated columnar &

goblet cells • Mucosal folds - micro turbinate • MALT

Blood supply

• Bony part - Tubal artery (accesory meningial artery) & caroticotympanic artery - internal carotid artery

• Cartilagenous part – internal maxillary,ascending palatine & ascending pharyngeal artery

Nerve Supply• Tympanic branch of IX CN –sensory and

parasympathetic secretomotor to tubal mucosa

• Pharyngeal branch of sphenopalatine ganglion - tubal ostium

• Nervus spinosus – cartilagenous part • Tympanic plexus – bony part

Differences Between Infant & Adult ETDifferences Between Infant & Adult ET

Infant Adult

Length 13-18 mm(approx.half) 36 mm

Direction more horizontal 45 deg to horizontal

10 deg at birth

Angulation at isthmus Absent present

Bony/cartilagenous bony more than 1/3rd bony 1/3rd

& wider cartilagenous 2/3rd

Tubal cartilage flaccid – causes reflux rigid -prevents reflux

Elastin Hinge density less more

Ostmann’s pad of fat less more

Functions of ET

1. Regulation of middle ear pressure & ventilation

2. Middle ear protection

3. Mucociliary Clearance & drainage

Regulation of middle ear pressure & ventilation

• Periodic opening & closing of NP end of the ET

• Co-ordinated contraction of TVP & LVP • Dilatation propagates from NP end to bony end.

• Surfactant B

• Opens 1- 2 times / hr

Opening and closing of ET

Closing of ET

• Passive phenomenon.

• Elastic recoil force generated by supporting structures & intraluminal mucosal adhesion force.

• Closure propogates towards NP end.

• ANS plays minor role

Mucociliary clearance & drainage

MIDDLE EAR PROTECTION

• Protection from nasopharyngeal environment

• Maintain the sterile environment

• Sound protection

ET FUNCTION TEST

1. Valsalva Manoeuver

2. Toynbee’s Manoeuver

3. Siegalisation & pneumatic otoscopy

4. Politzer Test

5. Catheterization

6. Tympanometry

7. Sonotubometry

8. ET Salphingography

8. Radiological Test

9. Sachharine or Methylene Blue Test

Valsalva maneuverPrinciple: positive pressure in the nasopharynx causes air to enter the Eustachian tube

Toynbee maneuver

- physiological

- swallowing with mouth and nose closed.

- retraction of tympanic membrane

Pneumatic otoscopy and Siegalization

FINDINGS

• Blowing sound - normal patency

• Bubbling sound - middle ear fluid

• Whistling sound - partial obstruction

• No sound - complete obstruction

8. Sono-tubometry

9. E.T salpingogram

10. C.T scan and MRI

11. Test for E.T patency in T.M perforation.

Dysfunction of Eustachian tube

•Mucosal and submucosal edema

•Decreased muscular function

•Failure of muscular coordination

•Mechanical obstruction

•Functional

Other causes

• Cleft palate

• Down’s syndrome

• Deviated nasal septum

• Sinusitis

• Nasal polyposis

• Barotrauma

Effect of ET blockage/dysfunctionTube blockage /dysfn

Absorption of ME gases

Negative pressure in ME

Retraction of TM

Transudate / haemorrhage

Acute otitis media

Perforation of TM

Sign & Symptoms

PATULOUS ET• Abnormally patent• Causes

– Idiopathic– Sudden weight loss

– Pregnancy 3rd trimester

– Multiple sclerosis

– Terminal malignancy– Contraceptive pills– Diuretics in elderly

• Complaints - ear blockage , autophony

- Disappears in supine position

• Tympanic membrane moves with inspiration and expiration

TREATMENT

MEDICAL

1.Nasal decongestants / antihistaminics.

2.Oral & intra nasal steroids

3.Antibiotics

SURGICALMyringotomy / grommet insertion

Tubal surgeries

1) Laser or microdebrider removal of superficial & deeper tubal mucosa.

2) Ballon tuboplasty

Patulous ET

Submucosal graft implantation/ cartilage slurry injection at NP tubal opening/ LASER cross hatching / endoluminal fat placement or suture ligation.

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