eustachian tube final pp anatomy,embryology,functions,dysfunctions treatment,patulous et
TRANSCRIPT
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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