Which surgical procedure involves an incision in the tympanum to release the increased pressure and exudate from the middle ear?

Pneumatic Otoscopy

Pneumatic otoscopy allows for visualization of the movement of the ear drum in response to a change in pressure within the ear canal. Similar to tympanometry, the movement of the TM depends on the pressure differential of the middle ear space. Unlike tympanometry, the examiner can visualize that movement. Relative movement of the TM during insufflation can predict negative middle ear pressure such as seen in eustachian tube dysfunction, or otitis media with effusion. This test can also be used to apply enough differential pressure for a bedside Hennebert's (fistula) test.

With the binocular microscope, a Bruening otoscope is used. The specula for this device have a more bulbous tip, also come in several sizes, and can be fitted with a rubber tip for oblong-shaped canals. The Bruening speculum is seated in the canal to form a tight seal and the bulb is squeezed. Movement of the pars tensa, pars flaccida and the manubrium of the malleus can be assessed. Pneumatic otoscopy has been shown to be a highly reliable way to assess for middle ear effusion and should be performed if there is any concern for or question of middle ear fluid.4

Pneumatic Otoscopy

Pneumatic otoscopy, which is a relatively simple procedure, can yield important information about middle ear pressure. It works on a simple principle. Remember the example of the plastic wrap and the effect of changes in middle ear pressure? Now imagine that the pressure changes are imposed from the other side of the membrane (i.e., from the external auditory canal). To perform this procedure, use an otoscope with a pneumatic bulb attachment(it is best to carry your own) and a special speculum with an expanded tip that forms an airtight seal in the external canal without the application of pressure. As an alternative, a small piece of rubber tubing placed over the tip of a standard speculum provides an excellent seal. Look through the otoscope while squeezing and releasing the rubber bulb (Fig. 7-6).

The normal tympanic membrane moves medially (away from you) when you apply external pressure by squeezing and moves laterally (toward you) when you create negative pressure by releasing the bulb. If middle ear pressure is already significantly negative and the eardrum is retracted medially, this pneumatic maneuver may produce only slight lateral motion of the drum when the bulb is released. If the middle ear pressure is abnormally positive, you may produce only slight medial movement when you apply positive pressure. If the pressure changes are significant, the drum may be immobile. Experience brings an appreciation of the nuances of these changes. As with every other aspect of the examination, you must see many eardrums move before you can recognize slightly reduced mobility.

Workup

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Pneumatic otoscopy

An insufflator attached to the otoscope head is used to move the tympanic membrane.

Fluid in the middle ear space inhibits this movement.

Tympanometry

Tympanometry incorporates sound energy to determine movement of the tympanic membrane.

Abnormal movements indicate abnormal pressures in the middle ear.

Tympanometry is used to evaluate and monitor middle ear effusions.

Spectral gradient acoustic reflectometry

Reflected sound waves indicate movement of the tympanic membrane.

This method is helpful when a seal of the canal cannot be achieved.

Tympanocentesis

The sample is used for a diagnostic culture.

The procedure provides pain relief.

It should be considered for the following conditions:

In the seriously ill patient with acute otitis media

For inadequate response to a second‐line antibiotic

In the neonate with acute otitis media

For immunosuppressed patients

For chronic effusion

For infants younger than 2 months with or without fever, consider further evaluation for extension of the infection and possible sepsis or meningitis.

D Pneumatic Otoscopy

50.

Is there any reason to perform pneumatic otoscopy?

Although not part of the routine exam, it can differentiate pathologic from normal eardrums, especially in children, whose tympanic membrane is often reddened by crying. In this case, a mobile eardrum (even if red) is more likely to be normal than the result of otitis media, and vice versa. In fact, reduced eardrum mobility increases the likelihood of middle ear infection by 40%. Reduced eardrum mobility also is quite serious in children, since it may impair hearing and language.

How is pneumatic otoscopy performed?

First visualize the tympanic membrane. Then attach a pneumatic bulb to the head of the otoscope, and squeeze it to observe any movement of the tympanic membrane. Since the normal eardrum is mobile (albeit slightly), airpumped into the external canal will make the membrane (and its light reflex) move inward, while air aspirated from the canal will make the membrane moveoutward. Any reduced mobility is therefore abnormal.Absent mobility reflects instead perforation, middle-ear adhesions, a blocked eustachian tube, or acute otitis media.

What if I do not have a pneumatic bulb?

A “poor man’s” way to test the mobility of the eardrum is to ask the patient to pinch his or her nose and then swallow. This creates enough of a pressure change to elicit a visible movement.

Otoscopy and Pneumatic Otoscopy

The physical examination of a normal TM reveals a pale gray and usually translucent eardrum. The middle ear landmarks include the short process and manubrium (or handle) of the malleus, which are in contact with the eardrum, and the chorda tympani nerve and incudostapedial joint posterosuperiorly, which are deep or medial to the TM but are usually visible through the eardrum (Fig. 5-3).

In AOM, the TM is thickened and edematous and sometimes pale yellow pus can be seen through the TM (Fig. 5-4). In the early phases of AOM (myringitis), the TM may be reddened, but diagnosis of ear disease cannot be confirmed unless a middle ear effusion is present. The strongest positive predictor of AOM is a bulging tympanic membrane that obliterates normal landmarks, followed by the finding of reduced mobility and then an opaque tympanic membrane.50 Redness alone is the least predictive because of the potential for false-positive results that can occur when the child cries. Occasionally, there may be a red effusion when hemorrhage has occurred in an inflamed middle ear.

In OME, the TM is usually mildly inflamed, sometimes with overlying blood vessels spread out in a radial fashion throughout the eardrum. The middle ear effusion may be thin and clear, with or without air bubbles, especially when serous effusion is present. It may be pale yellow or white if mucus is present. The TM is often diffusely retracted or concave (Fig. 5-5).

With CSOM, there is generally an associated perforation or draining tube present (Fig. 5-6). The otorrhea may be pale mucus or purulent in nature when a bacterial infection is present or pasty white with a fungal Candida infection. In some cases, pink granulation tissue may be seen and, if present in the inferior quadrants of the TM, a hidden and infected retained tube should be suspected (Fig. 5-7). Less often, the otorrhea relates to an underlying retraction pocket or cholesteatoma. It is important to ensure that the ear is reexamined once the exudate has been fully treated to exclude an underlying cholesteatoma. A cholesteatoma is more likely to be present if an attic or posterior superior retraction pocket is seen containing white keratin, granulation, or yellow wet debris (Fig. 5-8).

In addition to retraction pockets, long-standing changes that can occur related to middle ear disease include tympanosclerosis and atelectasis. Tympanosclerosis appears as white plaques containing calcium and phosphate in the middle fibrous layer of the three-layered TM; this tends to stiffen the TM. Tympanosclerosis or myringosclerosis is more commonly seen in the area of the pars tympani and often forms a horseshoe pattern in the lower half of the TM. It may change in pattern and distribution with time and is more commonly seen in children who have had tubes placed, but has also been reported in children who have had a history of OM without tubes (Fig. 5-9). Tympanosclerosis is rarely associated with hearing loss. Atelectasis or thinning of the TM is a more ominous finding and may develop because of chronic negative pressure in the middle ear space. In more severe cases, there may be associated long-standing mild hearing loss that only improves if the ear is ventilated with a tube. The TM is usually thinned, drapes over the ossicles, and may lie on the floor of the middle ear or promontory. In some cases, adhesive otitis media develops, in which the TM may become adherent and fixed to the middle ear floor, covering the ossicles so they become “skeletonized.” Hearing may or may not be affected (Fig. 5-10).

Pneumatic Otoscopy

Clinicians should use pneumatic otoscopy as a diagnostic method for OME.7,97 A meta-analysis showed that, when done by trained observers, pneumatic otoscopy has a sensitivity of 87% and specificity of 74%.98 Choosing the correct size of speculum to fit the patient's ear canal and obtaining a good pneumatic seal during an otoscopic examination both help to ascertain the motility of the tympanic membrane. The loss of normal movement of the eardrum during the gentle application of air pressure via a hand-held bulb indicates a loss of compliance of the eardrum. This may be seen with either an ME effusion or increased stiffness from scarring or thickening of an inflamed eardrum.

PATIENT SELECTION

All patients are examined carefully with an otologic microscope. Pneumatic otoscopy should always be included in the examination, because on occasion a serous effusion may not be readily apparent even with careful otomicroscopy. Tuning fork testing should also be used to confirm a conductive hearing loss. Even when the history and physical examination clearly indicate a chronic effusion, it is wise to formally test the hearing before manipulating the TM for both medicolegal and diagnostic purposes. Occasionally, chronic effusions are associated with normal hearing, thus leaving less reason to proceed with drainage. When conductive loss is present, determining the degree of loss can be helpful in ruling out additional pathology involving the conductive apparatus.

As for all office procedures, the surgeon must determine whether the patient will be able to tolerate the potential noise and discomfort without excess motion. Unilateral effusion in adults merits careful examination of the nasopharynx for adenoid hypertrophy or a mass lesion obstructing the orifice of the eustachian tube. The patient is instructed regarding the need for maintenance of a dry ear and the potential risk of TM perforation. Patients who are avid swimmers and disinclined to practice dry ear precautions may prefer to live with an effusion or undergo fitting with custom plugs before the procedure. Insertion of pressure equalization tubes may be difficult in patients with severe middle ear atelectasis. However, a small titanium tube can usually be inserted into the anteroinferior quadrant and often provides significant relief of aural fullness. The decision regarding whether to perform myringotomy alone versus proceeding with placement of pressure equalization tubes hinges on the desired duration of middle ear ventilation. A myringotomy may close within days and is therefore used when very short-term ventilation is needed. Serous effusions that occur acutely in the setting of an upper respiratory infection or after a flight will often resolve spontaneously, particularly if the patient is able to perform autoinsufflation or a Valsalva maneuver with successful ventilation of the middle ear space. A 3-day course of a nasal decongestant such as oxymetazoline (Afrin), as well as a nasal steroid spray, should be considered before myringotomy in these situations. Myringotomy should not be used as first-line therapy for uncomplicated acute otitis media. However, when significant otalgia is present, myringotomy does provide symptomatic relief. Myringotomy with tube insertion is indicated when acute otitis media persists despite antibiotics or is complicated by sensorineural hearing loss, vertigo, facial nerve paresis, mastoiditis or intracranial extension, meningitis, or a brain abscess. Vascular anomalies (aberrant carotid, dehiscent jugular bulb), as well as glomus tumors, may be mistaken for otitis media with effusion. When this possibility cannot be ruled out, imaging should be obtained before proceeding with a myringotomy because extensive bleeding and neurovascular complications may occur.

CLINICAL ISSUES

Head and Neck Examination

The head and neck examination is similar to that described previously. Additional information can be found by performing a fistula test, which can be done by either tragal pressure or pneumatic otoscopy. The patient is instructed to look straight ahead, and continuous positive and negative pressure is applied. Normally, the eyes will not drift, but a positive fistula test (Hennebert's sign) is manifest by the eyes drifting away from the tested ear with positive pressure and toward the tested ear with negative pressure. A positive fistula test is associated with a perilymph fistula, Meniere's disease, or superior semicircular canal dehiscence.17,19

The cranial nerve examination should be as thorough as possible, as every cranial nerve may be potentially affected in disease processes that cause vertigo. Oculomotor examination documenting the function of cranial nerves III, IV, and VI should be performed. Internuclear ophthalmoplegia produced by lesions in the medial longitudinal fasciculus of the lower midbrain and pons is important to recognize, as vertigo may be one of the manifesting signs of multiple sclerosis.16 Subtle abnormalities in cranial nerves V, VII, and VIII may indicate a retrocochlear lesion. These can be tested by closely examining facial symmetry at rest and during movement, performing the corneal blink reflex test, and performing tuning fork testing. Usually, though, patients with retrocochlear lesions will present with hearing loss rather than tinnitus or vertigo.16 Finally, cranial nerves IX, X, XI, and XII should be thoroughly examined.