EUSTACHIAN TUBE FUNCTION TESTS.powerpoint presentation

presentation on eustachian tube function tests

1. EUSTACHIAN TUBE FUNCTION TESTS

2. Eustachian tube Eustachian tube is a complex organ consisting of dynamic mucosal lined canal ,cartilage ,surrounding soft tissue, peritubal muscles, superior bony support and sphenoid sulcus. Also called auditory tube /pharyngotympanic tube Connects nasopharynx with tympanic cavity 36mm long runs down wards forwards and medially from its tympanic end forming angle of 45degree with horizontal

3. 2 parts : Bony –posterolateral ,forms 1/3 rd of total length Fibrocartilaginous –anteromedial forms 2/3 rd 2 parts meets at isthmus –narrowest part of tube Tympanic end 5*2mm in anterior wall of middle ear Pharyngeal end of tube slit like vertically Cartilage at this end raises elevation called torus tubarius situated in lateral wall of nasopharynx ,1-1.25cm behind posterior end of inferior turbinate .

4. Muscles related to eustachian tube : Tensor veli palitini - dilator tubae muscle Levator veli palitini Salpingopharyngeous The medial fibres of the tensor veli palatini are attached to the lateral lamina of the tube and when they contract help to open the tubal lumen. These fibres have also been called dilator tubae muscle. The exact role of the levator veli palatini and the salpingopharyngeus muscles to open the tube is uncertain

5. Elastin hinge : cartilage at junction of medial and lateral lamina at roof Rich in elastin fibres By its recoil it helps to keep the tube closed when no longer acted upon by dilator tubae muscle Ostmanns pad of fat : Mass of fatty tissues related laterally to membranous part of cartilaginous tube It also helps to keep tube closed protecting it from reflux of nasopharyngeal secretions

6. Histology : Mucosa - Pesudostratified ciliated columnar epithelium interspersed with mucous secreting goblet cells Submucosa –cartilaginous part of tube rich in seromucinous glands Nerve supply : Tympani branch of IXth nerve -sensory as well as parasympathetic secretomotor fibres to tubal mucosa Tensor veli palitini –mandibular branch of trigeminal nerve V3 Levator veli paliitni , salpingopharyngeus –motor supply by pharyngeal plexus(cranial part of IXth through vagus )

7. Functions Ventilation and thus regulation of middle ear pressure. Protection against ( i ) nasopharyngeal sound pressure and (ii) reflux of nasopharyngeal secretions. Clearance of middle ear secretions.

8. INFANT ADULT LENGTH 13-18MM 31-38MM DIRECTION MORE HORIZONTAL BIRTH TO AGE 7 10 DEGREE ANGLE WITH HORIZONTAL 45 DEGREE WITH HORIZONTAL ANGULATION AT ISHTMUS NO ANGULATION ANGULATION PRESENT BONY/CARTILAGINOUS PART BONY PART >1/3 RD OF TOTAL LENGTH WIDER 13/3 RD BONY 2/3 RD CARTILAGINOUS TUBAL CARTILAGE FLACCID RIGID DENSITY OF ELASTIN AT HINGE LESS DENSE ,TUBE DOES NOT CLOSE EFFICIENTLY BY RECOIL MORE ,HELPS TO KEEP TUBE CLOSED BY RECOIL OSTMANNS PAD OF FAT LESS IN VOLUME LARGE

9. EUSTACHIAN TUBE DYSFUNCTION Mechanical obstruction can result from intrinsic causes such as inflammation or allergy (ii) extrinsic causes such as tumour in the nasopharynx or adenoids. Functional obstruction is caused by collapse of the tube due to increased cartilage compliance, which resists opening of the tube or failure of active tubal opening

10. EUSTACHIAN TUBE FUNCTION TESTS 1 .Valsalva Test. The principle of this test is to build positive pressure in the nasopharynx so that air enters ET. patient pinches his nose between the thumb and index finger, takes a deep breath, closes his mouth and tries to blow air into the ears. If air enters the middle ear, the tympanic membrane will move outwards, which can be verified by otoscope or the microscope.

11. In the presence of a tympanic membrane perforation, a hissing sound is produced if discharge is also present in the middle ear, cracking sound will be heard. This test should be avoided ( i ) in the presence of atrophic scar of tympanic membrane which can rupture (ii) in the presence of infection of nose and nasopharynx

12. 2. Politzer Test. This test is done in children who are unable to perform Valsalva test. In this test, olive-shaped tip of the Politzer’s bag is introduced into the patient’s nostril on the side of which the tubal function is desired to be tested. Other nostril is closed, and the bag compressed while at the same time the patient swallows (he can be given sips of water) or says “ ik , ik , ik .”

13. By means of an auscultation tube, connecting the patient’s ear under test to that of the examiner, a hissing sound is heard if tube is patent. Compressed air can also be used instead of Politzer’s bag. The test is also used therapeutically to ventilate the middle ear

14. 3 .Catheterization. In this test, nose is first anaesthetized by topical spray of lignocaine eustachian tube catheter, the tip of which is bent, is passed along the floor of nose till it reaches the nasopharynx. Here it is rotated 90° medially and gradually pulled back till it engages on the posterior border of nasal septum

15. It is then rotated 180° laterally so that the tip lies against the tubal opening . A Politzer’s bag is now connected to the catheter and air insufflated. Entry of air into the middle ear is verified by an auscultation tube.

16. Complications Injury to eustachian tube opening which causes scarring later. Bleeding from the nose. Transmission of nasal and nasopharyngeal infection into the middle ear causing otitis media. Rupture of atrophic area of tympanic membrane if too much pressure is used.

17. 4. Toynbee’s Test. Toynbee’s maneuver causes negative pressure. It is performed by asking the patient to swallow while nose has been pinched. This draws air from the middle ear into the nasopharynx and causes inward movement of tympanic membrane verified by the examiner otoscopically or with a microscope.

18. 5. Tympanometry (Also Called Inflation–Deflation Test). In this test, positive and negative pressures are created in the external ear canal and the patient swallows repeatedly. The ability of the tube to equilibrate positive and negative pressures to the ambient pressure indicates normal tubal function. The test can be done both in patients with perforated or intact tympanic membranes

19. 6.Radiological Test. A radio-opaque dye, e.g. hypaque or lipoidal instilled into the middle ear through a pre-existing perforation X-rays taken should delineate the tube and any obstruction. The time taken by the dye to reach the nasopharynx also indicates its clearance function. .

20. 7.. Saccharine or Methylene Blue Test. Saccharine solution is placed into the middle ear through a pre-existing perforation. The time taken by it to reach the pharynx and impart a sweet taste is also a measure of clearance function. Similarly, methylene blue dye can be instilled into the middle ear and the time taken by it to stain the pharyngeal secretions can be noted.

21. 8. Sonotubometry . A tone is presented to the nose and its recording taken from the external canal. The tone is heard louder when the tube is patent . It also tells the duration for which the tube remains open. It is a noninvasive technique and provides information on active tubal opening

22. 9. Forced response test Patient with a patent ventilation tube or tympanic membrane perforation A tympanometry probe with specialized air pump placed in ear canal. Pressure applied via pump at ear canal until ET opens Resistance of the system can be measured

23. 10. ET endoscopy Hopkins 0 degree rigid scope/flexible nasopharyngoscope Dynamic function of ET valve evaluated Ptient vocalizes “Ka KA Ka ” to observe the isolated action of levater palatini as the palate rotates and rotataes torus tubaris medially. When patient swallows normal ET dialatory effort can be identified. A yawn or vocalizing “Ahh” produce maximal dialatory effort.

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