Siegel's Pneumatic aural speculum
This speculum is used to perform pneumatic otoscopy where the mobility of the ear drum can be tested. Ear drum mobility can be tested by varying the pressure levels at the external auditory canal and observing the movements of the ear drum in response to these pressure changes. Normal ear drum moves in response to pressure changes, i.e. it moves inwards when positive pressure is applied and moves outwards when negative pressure is applied.
Parts of Siegel's speculum:
- Bulb - Made from rubber with a one way valve which will enable it to pump out air. It is connected by a rubber tube to a speculum adapter.
- The speculum adapter is provided with a slanting lens which is convex in nature. This lens provides 2 1/2 time magnification of the image.
- Three aural specula are provided. Their sizes being 4, 5, and 6 mm. These aural specula fits snugly into the speculum adapter.
Immobility of ear drum even during pressure changes in the external auditory canal is caused by:
1. Presence of fluid in the middle ear cavity (otitis media with effusion). Pneumatic otoscopy is diagnostic in identifying middle ear effusion
4. Adhesive otitis media where the drum could be retracted and plastered to the middle ear promontory
Components of Siegel's pneumatic speculum:
1. Rubber bulb which is used to create pressure differential at the level of ear drum. Applying pressure by compressing the bulb increases the pressure at the level of ear drum pushing it inside.
2. Rubber tube which connects the bulb to the speculum
3. Aural speculum. It should snugly fit into the external canal of the patient in order to create effective pressure differential at the level of ear drum
4. Eye piece which is placed obliquely to make it parallel to the ear drum. The lens is convex and creates a magnification of two and half times.
Uses of Siegels speculum:
1. Siegelization: This test is done to test the mobility of the ear drum. The speculum should be snuggly fitting for this test to be performed. The speculum should be introduced in such a manner that the eye piece is oriented towards the antero inferior slant of the ear drum. Pressure at the external canal is applied by pressing the bulb. The ear drum could be seen moving inwards. On releasing the pressure in the bulb negative pressure is created pulling the ear drum towards the speculum. Normally this to and fro movement of the ear drum can be observed during this procedure.
2. Fistula test: On performing siegelization test if the patient is having fistula of the lateral canal then the patient will experience giddiness and nystagmus could be observed. This is positive fistula test.
3. Examination of external ear and tympanic membrane. Since it provides two and half times maginification examination of ear drum is facilitated
4. Instillation of medications. Medications can be pushed to reach the middle ear cavity through pre existing perforation by filling up the ear canal with medicine and applying pressure using siegel speculum