Acute Otitis Media and Otitis Media with Effusion

• Anatomy of the middle ear—see p. 12

• Assessment of middle ear function—see p. 58

• Acute infections of the external ear—see p. 111

• Surgical management of AOM and COME—see p. 291

Introduction

AOM and OME are among the commonest reasons for a child to visit the pediatrician’s office aside from a well-baby visit and account for a substantial number of antibiotic prescriptions, surgical procedures, and missed school and parental work days, thereby making the economic impact enormous. Despite treatment, complications and sequelae of AOM and OME continue to occur and can be life-threatening in some instances.

Pathophysiology (Fig. 4.7A–C)

AOM and OME are known to result from either eustachian tube dysfunction (ETD, see p. 9) or primary infection (viral or bacterial) and/or inflammation of the middle ear space. The most common form of ETD results from luminal obstruction, thereby impeding normal physiologic gas homeostasis, drainage, and protective mechanisms (ciliary clearance) that prevent micro-organism ascension to the middle ear. Since the normal eustachian tube is closed at rest, tubal obstruction can result from either failure of the opening mechanism in the setting of an otherwise anatomically normal tube (e.g., tensor veli palatini muscle paralysis) or an abnormal tube (e.g., cleft palate). More commonly, anatomical obstruction of an otherwise normal eustachian tube can occur secondary to either intrinsic (e.g., inflammation and edema) or extrinsic (e.g., adenoid hypertrophy or tumors) factors. Classically, ETD results from a viral upper respiratory infection in children. Epithelial surface infection impairs mucociliary clearance, results in mucosal edema, and thickens secretions. Inflammation promotes intrinsic eustachian tube obstruction through contiguous mucosal edema as well as extrinsic obstruction through associated adenoid hypertrophy (Fig. 4.7A). Eustachian tube obstruction can result in OME because failed pressure regulation with continued gas resorption results in middle ear underpressure and ultimate transudation (serous OM) owing to the imbalanced Starling forces. Failed drainage and mucociliary clearance further enhance the situation. Should viral infection or secondary bacterial infection extend to the middle ear mucosa, then middle ear inflammation will ensue, producing the signs and symptoms of acute inflammation (AOM). Common viruses that have been associated with the previously mentioned scenario include: influenza A and B, respiratory syncytial virus, parainfluenza virus, the enteroviruses, and rhinoviruses. Classically, AOM episodes have been associated with middle ear infection with one of three common respiratory bacterial pathogens: Streptococcus pneumoniae, Haemophilus influenzae (nontypable), and Morax-ella catarrhalis (Fig. 4.7B). It is also now clear that upper respiratory tract viral infections with one of the previously mentioned pathogens not only can lay the groundwork for secondary bacterial infection but might also produce synchronous co-infection with bacterial pathogens.

In contrast to the acute, infectious scenarios described above, when chronic middle ear inflammation or eustachian tube obstruction persists, chronic OME (COME) can result. In these cases, signs of middle ear inflammation are often lacking or have resolved following an episode of AOM, producing only hearing loss, a clogged sensation, and evidence of middle ear Effusion on physical examination. In this situation, the previously mentioned bacteria and viruses are much less commonly isolated (Fig. 4.7C) and a search for causes such as allergies, adenoid hypertrophy, anatomical deformity of the eustachian tube, neurologic disorders, and nasopharyngeal tumors is indicated.

Clinical and Diagnostic Evaluation (Fig. 4.7D–G)

The symptoms of AOM can include both ear- specific and a wide variety of constitutional symptoms. Symptoms relating to an associated viral illness are also common. Ear-specific symptoms include: otalgia and hearing loss. Upper respiratory tract and constitutional symptoms might include fever, malaise, myalgia, rhinorrhea, nasal congestion, and cough. In very young infants, diarrhea, abdominal pain, nausea, and vomiting can also occur. Hence, any child with an upper respiratory tract or gastrointestinal illness should probably be investigated for AOM. Comprehensive physical examination is often needed given the broad range of symptoms that can be displayed. General examination can reveal an ill-appearing child with lethargy, rhinor-rhea, cough, and pulling at the ears. Otoscopy times reveal a bulging, erythematous, opaque, or even perforated tympanic membrane (TM) (Fig. 4.7D, E). In the case of the intact TM, pneumatic otoscopy reveals either poor or absent mobility to applied ear canal pressure. In the case of viral-associated AOM, vesicles or bullae on the surface of the TM may be seen (Fig. 4.7G).

By contrast and definition, children with OME generally display no ear-specific signs of acute inflammation (i.e., otalgia) and few if any systemic symptoms except when associated with an upper respiratory tract illness. These children might complain of hearing loss or their parents might notice reduced responsiveness to sound or pulling at their ears. Otoscopic examination shows an intact TM that is either opaque or, when the middle ear is only partially filled with liquid, an air–fluid level. When inflammation is minimal but present, the TM might display a radially injected pattern (Fig. 4.7F). In some instances, the TM might be somewhat retracted owing to chronic middle ear underpressure and pneumatic otoscopy will reveal either absent mobility or mobility only when negative pressure is applied to the ear canal.

Adjunctive testing in cases of AOM is rarely necessary as the diagnosis is usually evident. However, in cases where the ear canal is extremely small or obstructed by cerumen, the child is uncooperative, or the signs and symptoms of acute middle ear inflammation are lacking (OME), tympanometry and behavioral audiometry can be a useful adjunct to physical examination. However, it is imperative to recognize that tympanometry and audiometry do not diagnose middle ear Effusion (see p. 58). Rather, these tests can only help identify altered TM compliance and mobility or an associated conductive hearing loss in the setting of a child who is suspected of having OME. When tympanometric or audiometric abnormalities persist, formal microscopic examination is always indicated.

Complications

With the advent of antibiotics and improved access to medical care, serious complications from AOM and OME have become much less common. More importantly, the liberal use of antibiotics has made these complications much less apparent when present and a greater degree of suspicion is needed to identify affected patients. Complications of AOM and to a lesser extent OME can be divided into those that affect the temporal bone and contiguous extracranial structures and those that involve the central nervous system (intracranial). Intratemporal complications include: TM perforation, chronic suppurative OM with or without cholesteatoma formation, tympano-sclerosis, ossicular erosion, hearing loss, facial paralysis, mastoiditis, subperiosteal abscess, labyrinthitis, and petrous apicitis. Intracranial complications can include: epidural (perisinus) abscess, sigmoid sinus thrombophlebitis and thrombosis, subdural abscess (empyema), brain abscess, meningitis, and otitic hydrocephalus. Each of these complications is discussed in more detail in later sections.

Management (Fig. 4.7H)

Analgesics and antimicrobial therapy are the cornerstone treatments for episodes of AOM. Prospective, randomized clinical trials have clearly demonstrated efficacy of antimicrobial therapy over placebo for the treatment of AOM. Moreover, the frequency of complications (see previous discussion) has dramatically decreased following the institution of antibiotic treatment for this disease. Nevertheless, the routine use of antibiotics has recently been debated because of a relatively high spontaneous remission rate. For children with uncomplicated AOM that is not severe, a period of watchful waiting with careful observation and analgesics is now considered a viable alternative to antibiotic administration at the first visit. However, when fever and otalgia persist beyond 24–48 hours or signs of worsening illness are evident, an appropriate antibiotic should be administered. The most common antibiotics currently in use for AOM are illustrated in Fig. 4.7H. Clearly, the observation treatment paradigm mandates parental vigilance and compliance.

When an antibiotic treatment failure has been documented by persistent symptoms, a resistant organism or a complication should be suspected and treatment should be tailored. This usually requires consideration of an imaging study and/or the possibility of infection with either a β-lactamase-producing organism (Haemophilus influenzae or Moraxella catarrhalis) or penicillin-resistant Streptococcus pneumoniae. A low threshold for diagnostic tympanocentesis should exist to document the causative organism. Moreover, while myringotomy alone is rarely therapeutic for AOM, tympanostomy tube insertion in selected cases can immediately relieve symptoms and provide drainage of the infection.

Prevention of recurrent episodes of AOM (RAOM) includes assessment of risk factors (see previous discussion) with appropriate modifications when possible, assessment of vaccination status, and consideration for surgical intervention. Use of the heptavalent pneumococcal vaccination (Prevnar) has become routine for preventing invasive infection in infants (meningitis and pneumonia). While it was secondarily hoped that this vaccine would drastically change the AOM attack rate among young children, this finding has not been realized to date. Moreover, vaccinations for nontypable Haemophilus influenzae and Moraxella catarrhalis are currently not available. Active treatment for upper respiratory tract viral infections should prevent cases of AOM, although the timely identification of and intervention against these infections remain elusive.

Prospective randomized clinical trials have demonstrated the efficacy of tympanostomy tube insertion for children with RAOM. In this setting, tympanostomy tubes reduce the number of AOM episodes as well as reduce the morbidity (otalgia, hearing loss) of episodes when they do occur.

Chronic OME is defined as middle ear Effusion that has been present for longer than 3 months. Since antibiotics and antihistamines are mostly ineffective for this disorder, careful observation and surgical intervention remain the mainstay treatments. Factors that must be considered in these patients include: symptoms, degree of hearing loss, associated structural changes in the tympanic membrane, the presence of an underlying sensorineural hearing loss or speech and language delay, and associated medical disorders such as craniofacial disorders and immunodeficiency. In children with 3 months of OME without any of the previously mentioned risk factors or hearing loss, a period of watchful waiting with repeated audiometric testing is considered appropriate. First-line surgical therapy for refractory COME includes tympanostomy tube insertion as prospective randomized clinical trials have demonstrated efficacy. Tympanostomy tubes drain the fluid from the middle ear space, thereby improving aeration. This intervention can resolve the conductive hearing loss that results from middle ear fluid and as restore tympanic membrane neutrality.

Potential complications from tympanostomy tubes can include: otorrhea, tube retention, foreign body reaction with granuloma formation, tympanic membrane perforation, and the risks of anesthesia.

Recommended Reading

Gates GA, Avery CA, Prihoda TJ, Cooper JC Jr. Effectiveness of adenoidectomy and tympanostomy tubes in the treatment of chronic otitis media with Effusion. N Engl J Med 1987;317(23):1444–1451

Senturia BH, Bluestone CD, Klein JO, et al. Report of the Ad Hoc Committee on Definition and Classification of Otitis Media with Effusion. Ann Otol Rhinol Laryngol 1980;89:3–4

Chronic Suppurative Otitis Media (Chronically Draining Ear)

Otitis media is defined as an inflammatory process of the middle ear space and mastoid air cell system. An unresolved or continued inflammatory process in the presence or absence of infection can lead to chronic suppurative otitis media (CSOM or chronically draining ears) if not resolved within 3 months. Typically, this chronic process is entertained by a nonhealing perforation of the tympanic membrane. Clinically, chronically draining ears should be further subclassified into safe and nonsafe ears, depending on the presence of a cholesteatoma.

Chronic Suppurative Otitis Media without Cholesteatoma, Adhesive Otitis Media, and Granulomatous Middle Ear Disease

Definition

Chronic suppurative otitis media (CSOM) is defined as a chronically draining ear for more than 3 months typically in the setting of a nonhealing tympanic membrane perforation. Chronically draining ears with cholesteatomas will be discussed in the next section. Causes for the TM defect include retraction pockets and perforations mostly arising due to chronically negative middle ear pressure (eustachian tube dysfunction), prior pressure equalization (PE) tube placement, and trauma. Chronic negative pressure resulting in retraction and subsequent collapse of an atrophic tympanic membrane (adhesive and atelectatic otitis media) are not associated with frank perforations but are considered a form of otitis media and will be discussed in the following section.

Closely Related Topics

• Anatomy of the middle ear—see p. 12

• Physiology of the middle ear—see p. 27

• Computed tomography (CT)—see p. 95

• Surgery for chronic otitis media—see p. 299

Introduction

Chronic otitis media (COM) is thought to result from continued inflammation or unresolved Effusion whether the Effusion was purulent, serous, or mucoid. Chronic suppurative otitis media (CSOM) is almost always associated with a perforation in the tympanic mem brane (TM), whether from repeated insults or unresolved inflammation leading to tissue weakening. Patients will present with chronic persistent or recurring otorrhea, often foul smelling, and hearing loss in the setting of CSOM. Rare infections and chronic granulomatous disorders including tuberculosis, Wegener granulomatosis, sarcoidosis, syphilis, and mycotics may be seen in the middle ear and will be discussed within this section. Complications may arise from COM and will be discussed further on p. 141 and in Chapter 5, p. 299.

Pathophysiology (Fig. 4.8A–D)

Chronic suppurative otitis media is characterized by chronic purulent otorrhea in the setting of a perforation of the tympanic membrane. This drainage can be intermittent or persistent, or sometimes central perforations remain dry, which is thought to be a dormant version of CSOM. Inflammation and possible infection in COM is most often preceded by AOM, leading to mucosal edema and infection causing chronic suppurative symptoms. Sequelae of the ongoing inflammation can lead to accumulation of granulation tissue, which eventually can cause polyps within the middle ear and subsequent blockage of mastoid aeration (Fig. 4.8A). In the setting of long-standing ETD, atelectasis of the middle ear can occur, leading to deep retraction pockets of the TM (Fig. 4.8B, C). These retractions can lead to bony erosion with subsequent ossicular destruction, from complete retraction of the TM to the medial wall of the middle ear and obliteration of the middle ear cavity, which constitutes adhesive otitis media (Fig. 4.8D). Cholesteatoma formation is also possible in a similar scenario, and will be discussed further on p. 136.

Permanent changes can be seen in the mucosa along with possible erosion in the surrounding bone with chronic obstruction and infection of the attic and antrum in the setting of CSOM. CSOM can be described as a continuous cycle of infection, inflammation, granulation, and ulceration. Of note, the most common bacteria associated with CSOM vary from those associated with AOM. The pathogens isolated are Pseudomonas aeruginosa, Staphylococcus aureus, Proteus species, Klebsiella pneumoniae, and anaerobes, with P. aeruginosa being the most common. This has bearing on the medical treatment associated with CSOM and the choice of antibiotic, which varies from that for AOM. Most cases are responsive to otic antibiotic suspensions with or without steroid preparations depending on the presence of absence of granulation tissue.

Fig. 4.8 A–E

Radiographic Studies (Fig. 4.8E, F)

Computed tomography has replaced conventional plain radiographic studies in the work-up for chronic otitis media. High-resolution CT (HRCT) can typically provide morphologic information about the degree of mastoid pneumatization, the status of the tegmen, and the thickness and position of the tympanic membrane. Also, CT can show labyrinthine anatomy and visualize the ossicular chain to some degree (Fig. 4.8E). However, without a strong clinical suspicion for cholesteatoma, CT is typically not necessary. With atelectatic middle ears, CT can assess the status of middle ear aeration and thus give the clinician information for proper patient counseling (Fig. 4.8F).

MRI is typically not helpful in delineating chronic ear disease. Plain film radiography such as the Schüller view has been used to assess mastoid pneumatization and provide some information about anatomical landmarks.

Rare Infections of the Middle Ear

Infections by rare pathogens, such as Mycobacterium tuberculosis, are thought to reach the middle ear by hematogenous spread. Tuberculosis of the middle ear will have early bony destruction, with late caseation, as well as granulomas similar in histopathologic make-up to tuberculosis outside the middle ear, including giant cells, epithelioid cells, and lymphocytes. Multiple perforations are the hallmark finding in this setting. Wegener granulomatosis is a granulomatous inflammatory disease with concomitant necrotizing vasculitis. It is predominantly found in the upper and lower respiratory tract and kidneys, but can also affect the temporal bones, cochlear vessels, and nerves. Sarcoidosis is an autoimmune disease and affects the middle ear space by direct granulomatous involvement, as well as disturbing the facial, auditory, and vestibular nerves. Syphilis infection of the middle ear can be congenital or acquired, with active middle ear involvement occurring during the late latent or tertiary phases. Syphilis can involve the ossicles and mastoid bones with a leukocytic infiltrate, or tertiary syphilis gummas may occlude or perforate the middle ear mimicking CSOM, with granulomatous mucosa on histology as well. Mycotic organisms are found everywhere, but infections of the middle ear are rare and the main occurrences are in immunocompromised patients.

Histiocytosis X can present with chronic persistent otorrhea and therefore mimic CSOM. Other signs of the disease (diffuse bony lesions, hepatosplenomegaly, exophthalmos) and absent response to local and systemic antibiotics with the presence of granulation tissue should raise clinical suspicion. Histologic confirmation of the diagnosis is necessary.

Epidemiology

Studies have reported the percentage of OM cases that progress to COM. Numbers have varied according to size of perforation, presence or absence of otorrhea, and presence or absence of ventilation tube. Overall the number is estimated at 40 cases per 100 000 persons for those aged 15 years and younger, with 1%–3% of those patients having previous ventilation tube placement and continued otorrhea. In the case of granulomatous otitis media, the incidence is rare, especially for tuberculosis of the middle ear, with an incidence of 0.1% in most series. Otologic involvement of other granulomatous disorders has not been well studied. However, small series have reported otologic involvement ranging from 10% to 60% in Wegener granulomatosis, sarcoidosis, and syphilis.

Clinical Presentation (Fig. 4.8G–I)

Presentation of chronic suppurative otitis media includes ear discharge (otorrhea) varying in consistency through purulent, serous, or even soft and curdled on physical examination. Otorrhea can be intermittent or persistent and typically subsides after a course of topical antibiotic eardrops. Patients often present with complaints of hearing loss and in more severe cases may report fever, pain, and vertigo, all of which can suggest intracranial or CNS involvement.

On physical examination the canal can be edematous, and often granulation tissue can be seen on otoscopy (Fig. 4.8G, H). The perforation itself should be described thoroughly in its size and exact location since this will have direct implications for the choice of surgical technique. Visualization through the perforation will give you access to the middle ear mucosa, which will also be edematous, erythematous, or even polyp-ridden.

Audiometric examination should be performed in every patient. Usually, various levels of conductive hearing loss can be observed. With an intact ossicular chain in the setting of a small perforation, hearing can sometimes be normal. With long-standing infection, on the other hand, inner ear function can be affected, mostly resulting in a mixed hearing impairment. Some patients report fluctuating hearing correlating with the current state of the infection (mucosal edema seems to provide some sound conduction). Also, the amount of the conductive component can provide evidence for ossicular involvement. As with cholesteatoma, the long-standing infection can activate cellular and extracellular mechanisms leading to bony erosion. The long process of the incus is most commonly affected first. Similarly to the morphologic descriptive process of documenting perforations of the tympanic membrane, retractions should also be classified to monitor progression (Fig. 4.8I).

Fig. 4.8 F–L

Clinical Implications of Rare Infections and Granulomatous Diseases

Rare infections and granulomatous disease of the middle ear can all mimic CSOM, yet many also have characteristic presentations. Middle ear tuberculosis often has a typical whitish appearance and its granulations have a slight tendency to bleed. Patients with multiple TM perforations will coalesce into loss of the TM, all in the setting of neck lymphadenopathy. The multiple perforations of the tympanic membrane are typical for middle ear tuberculosis. As cultures may, but often do not, produce tubercle bacilli, identification by polymerase chain reaction has become of high diagnostic value.

Many symptoms of Wegener granulomatosis are systemic in origin such as fever and arthralgia, but can include headaches, chronic rhinosinusitis, and symptoms of chronic otitis media. A positive anti-neutrophil cytoplasmic antibody (cANCA) result can be helpful in establishing the diagnosis of Wegener granulomatosis. Sarcoidosis can manifest in the head and neck with facial palsy, vertigo, sudden sensorineural hearing loss (SNHL), or granulomatous disease within the middle ear. Sarcoidosis can commonly be involved in a known cluster presentation of symptoms characterized by parotitis, uveitis, facial nerve paralysis, and fever referred to as uveoparotid fever or Heerfordt syndrome. Otologic manifestations of syphilis include sudden SNHL, TM perforation, and possible Ménière-like symptoms. Mycotic diseases can involve the mastoid and middle ear. Invasive temporal bone mycoses are rare. They are usually associated with host immunodeficiency and are difficult to diagnose, and many cases are fatal.

Tympanosclerosis (Fig. 4.8J, K)

Tympanosclerosis is characterized by deposition of calcium and hyalinization of collagen within the lamina propria of the middle ear mucosa. Otoscopically, these deposits can be seen as white crescent-shaped plaques in the tympanic membrane (Fig. 4.8J, K).When limited to the TM, the term myringosclerosis is commonly used. With broad involvement of the middle ear, deposits around the ossicles with subsequent fixation (especially the stapes footplate) can result. Tympanosclerosis is common in patients with a florid history of recurrent AOM, COM, or multiple sets of PE tubes.

Complications

Complication of COM can arise and include: Bezold abscess, subperiosteal abscess, mastoiditis, labyrinthitis, SNHL, petrous apicitis, facial paralysis, cholesteatoma, labyrinthine fistula, epidural abscess, lateral sinus thrombosis, meningitis, and brain abscess. See p. 141 for details.

Management (Fig. 4.8L)

As described above, the primary treatment for COM includes antibiotic treatment selective for the most common pathogens discussed previously. Antibiotic suspension drops are considered first line with the addition of steroid additives if granulation tissue is suspected (Fig. 4.8L). Also, good ear canal hygiene and cleaning techniques must be stressed to all patients to allow the antibiotic suspension to penetrate past the exudate accumulated within the EAC. Techniques for instillation of 50% hydrogen peroxide and 50% sterile water are well tolerated by most patients. Failure of topical medications is rarely due to resistant organisms given the high concentrations achieved with direct application of the topical therapies. Treatment failure in this scenario can arise from continued obstruction and failure of medication to reach the target. In these cases, systemic antibiotic choices may be tried or, if a specific organism has been isolated, oral antibiotics may be used to target the particular pathogen. Often fluoroquinolones are used, given that the oral bioavailability is usually equivalent to the parenteral route. If CSOM fails to be controlled by medical management alone, then surgical management must be considered. Without cholesteatoma, tympanoplasty procedures aim at recreating an intact TM, while leaving an aerated middle ear space free of disease. Ossiculoplasty may be necessary for reconstructing the ossicular chain. For a more thorough description of these surgical interventions, refer to Chapter 5, p. 299.

Regarding rare infections and systemic disease involvement of the middle ear, management of each must be looked at individually. Many of these disease processes require a multidisciplinary approach for holistic treatment of the patient. Tuberculosis management involves systemic treatment of the mycobacterium with possible need for mastoidectomy for any sequestered or necrotic bone. Wegener granulomatosis and sarcoidosis are also treated systemically, often with immunosuppressive medications, including high doses of corticosteroids, especially with cranial nerve involvement. In syphilis, traditional penicillin treatment with use of corticosteroids for SNHL is the standard of care, with treatment until the serologic markers normalize. Lastly, with mycotic infections, treatment consists of antifungal chemotherapy such as amphotericin B, surgical debridement, and attempts to control the underlying immunologic condition in most cases.

Recommended Reading

Kenna MA, Bluestone CD, Reilly JS, Lusk RP. Medical management of chronic suppurative otitis media without cholesteatoma in children. Laryngoscope 1986;96(2):146–151

Skolnik PR, Nadol JB Jr, Baker AS. Tuberculosis of the middle ear: review of the literature with an instructive case report. Rev Infect Dis 1986;8(3):403–410

Cholesteatoma

Definition

Cholesteatoma is defined as an accumulation of squamous epithelium and keratin debris trapped within the tympanomastoid compartment. Based on its underlying pathophysiology, several types of cholesteatoma have been described: congenital cholesteatomas arise from ectodermal epidermoid formations mostly in the anterior superior aspect of the middle ear. Acquired cholesteatomas have to be further subdivided into primary or secondary acquired forms. Chronic otorrhea is the most common presentation and, if left untreated, cholesteatoma can lead to several potentially fatal complications.

Closely Related Topics

• Anatomy of the middle ear—see p. 12

• Assessment of middle ear function—see p. 58

• Chronic suppurative otitis media (CSOM)—see p. 130

• Complications of chronic otitis media—see p. 141

Introduction (Fig. 4.9A)

The term cholesteatoma, first coined by Müller in 1838, is truly a misnomer. Although the keratin fragments first described resembled cholesterol crystals, cholesteatomas lack true cholesterol. The cystic structure is lined by squamous epithelium (matrix), and the accumulation of the desquamated debris into the center of the cyst results in the expansile character of the lesion. The cholesteatoma matrix is surrounded by a layer of connective tissue, the perimatrix, which entertains a chronic inflammation with subsequent mucosal invasion and destruction of surrounding bone (Fig. 4.9A).

Congenital Cholesteatoma

Congenital cholesteatoma is thought to arise from entrapment of squamous epithelium during embryogenesis. Congenital cholesteatomas come from embryonic ectodermal epithelial rests within the middle ear. First described by Teed, they most often arise from near the geniculate ganglion medial to the head of the malleus. Classically, a congenital cholesteatoma is found in the anterior mesotympanum, with an intact TM and without history of otitis or ear disease.

Pathophysiology of Primary Acquired Cholesteatoma (Fig. 4.9B–E, G, H)

Epitympanic cholesteatomas are more frequently the site of primary acquired cholesteatomas arising from Prussak’s space. Extension and limitation of growth are dictated by the anatomical boundaries, with direction being determined by the ligaments and folds of the mesotympanum and epitympanum. These boundaries or anatomical pathways can also determine the type of complications expected. Primary acquired cholesteatomas arise from negative pressure causing a retraction pocket of the TM over the ossicles (Fig. 4.9B), most often from persistent eustachian tube dysfunction (ETD). Increasing retraction of the pars flaccida leads to erosion of the scutum and possible ossicular disruption and destruction. Consistent with the invagination theory, entrapment of keratinized squamous epithelium within the retraction pockets leads to cholesteatoma formation. The cholesteatoma can continue to progress with eventual erosion through the mastoid or even erosion of the lateral semicircular canal leading to hearing loss and vertigo. Posterior mesotympanic cholesteatomas are also classified as primary acquired cholesteatomas, and again retraction of the tympanic membrane occurs, except into the posterior middle ear. The anatomical pathway of primary acquired cholesteatomas arising from the posterior tympanic membrane is more likely to produce facial nerve exposure and complications therein.

In summary, several sites of primary acquired cholesteatoma should be distinguished (Fig. 4.9C):

• Attic cholesteatoma arising from the pars flaccida and extending primarily into the attic and antrum. Most primary acquired disease seems to originate in this area (Fig. 4.9D, E, H) resulting from a combination of persistent retraction and proliferation of keratinized (squamous) epithelium. In this way, the self-cleaning mechanism of the epithelium becomes interrupted and debris subsequently accumulates in the base of the retraction, resulting in a chronic inflammatory process. The intraepithelial maturation process of basal keratinocytes has been modified and a true cholesteatoma forms expanding deeper into the tympanomastoid compartment.

• Sinus cholesteatoma originating from a posterior retraction of the pars tensa and primarily extending into the sinus tympani. The sinus tympani is an anatomically challenging space since it lies medial to the mastoid segment of the facial nerve (Fig. 4.9F, G). Also, the sinus tympani opens in an axis perpendicular to the surgeon’s best view. Complete bone removal over the anterior portion of the mastoid segment of the facial nerve seems fundamental in managing sinus tympani disease.

Fig. 4.9 A–E

• Tensa-retraction cholesteatoma originating from a completely retracted tympanic membrane (see atelectatic or adhesive otitis media). These cholesteatomas may extend into the eustachian tube orifice and the hypotympanic air cells. Further extension may proceed toward the posterior middle ear and anterior attic.

Pathophysiology of Secondary Acquired Cholesteatoma (Fig. 4.9A)

Secondary acquired cholesteatomas arise from previous insult to the TM, including trauma, AOM and COM, or surgical manipulation including ventilation tube placement. The insult allows a pathway of epidermal in-growth into the middle ear space, also termed the epithelial invasion theory (Fig. 4.9A). Anatomically posterior insults are thought to result in cholesteatoma formation more so than central perforations, although central perforation cholesteatomas do occur. Disruption of the TM makes the TM more susceptible to retraction pocket formation and possible accumulation and entrapment of debris within that pocket, promoting cholesteatoma formation.

The basal cell hyperplasia theory describes scenarios of microcholesteatoma formation within microscopic disruptions of the basal cell layer of the TM and continued inflammation or infection promoting expansion and further accumulation of debris. This could allow for cholesteatoma in the setting of a clinically intact TM, similar to congenital cholesteatoma if no obvious inflammation was present. This reasoning of ongoing inflammation and infection has also led to the squamous meta-plasia theory, which suggests transformation of the simple epithelium into keratinizing epithelium in the setting of an ongoing infection. The direct contact and inflammation allows for perfo-ration of the TM, which then mimics an epitympanic cholesteatoma with differentiation only by histologic means.

Epidemiology

The exact prevalence of cholesteatoma is unknown. The incidence (per 100 000 per year) has been reported as 3 in children and 12.6 in adults. However, a high volume may be seen in tertiary care institutions, as expected based on referrals and due to the complicated clinical nature of cholesteatomas.

Clinical Presentation (Fig. 4.9G–I)

The history of present illness of cholesteatoma can mimic CSOM with painless, recurrent or persistent otorrhea, and a TM perforation in the majority of cases. COM refractory to treatment should spark further investigation for cholesteatoma formation. Hearing loss can be another presenting complaint, with audiologic examination often most consistent with a conductive hearing loss. As with CSOM without cholesteatoma, long-standing disease might lead to mixed hearing impairment with involvement of the inner ear. Rarely, a labyrinthine fistula can result from marked labyrinthine bone erosion mostly over the lateral semicircular canal. In such cases, a positive fistula test (air insufflation into the EAC, with resulting vertigo and nystagmus) further supports this diagnosis.

On otoscopic examination, debris within the external auditory canal should be cleaned to provide a clear view of the tympanic membrane (Fig. 4.9G, H). Often, a perforation can be observed mostly in the superior (epitympanic) aspect of the TM. Sometimes, deep retraction pockets that are not fully visible can contain cholesteatoma. Furthermore, many otologists would consider a deep, not fully visible epitympanic retraction pocket of the pars flaccida as a cholesteatoma (Fig. 4.9I). Hence, surgical intervention is often recommended even in the absence of clinically relevant otorrhea or other signs of middle ear disease.

With congenital cholesteatomas, otoscopy reveals an anterior mesotympanic mass behind an intact tympanic membrane.

Diagnosis (Fig. 4.9J, K)

Radiographic testing is not recommended routinely in the initial diagnosis of cholesteatoma. A high–resolution CT scan without contrast can help delineate the extent and boundaries of cholesteatomas (Fig. 4.9J, K). This may also help in evaluating suspected ossicular or otic capsule erosion, or when there is discrepancy between the history and physical examination findings. The integrity of the tegmen should also be evaluated.

Fig. 4.9 F–K

Bone Erosion

Bone destruction is believed to come from two separate processes, either pressure-induced effects on the bone from entrapment and expansion of the debris, or enzymatic and chemical digestion from bacterial and host biochemical factors. Although many have questioned the pressure hypothesis and the ability of cholesteatomas to reduce capillary blood flow enough to lead to bony erosion, both processes are probably involved. The accepted hypothesis now is that the inciting event leads to increased activity of osteoclastic cells and factors, leading to further bone destruction. Cholesteatomas are prone to infection and can have permanent sequelae including hearing loss and CNS involvement, both of which can necessitate surgical management.

Complications

Bony erosion of the ossicles, otic capsule, facial nerve canal, tegmen tympani, and mastoid tegmen (leading to possible intracranial pathology) can all arise from cholesteatoma progression and expansion. Hearing loss from ossicular erosion is very frequent with the incus affected most commonly. In this setting, a present and mobile stapes super-structure serves as a good prognostic indicator for successful ossiculoplasty (see Chapter 5, p. 306).

Vertigo results from erosion of the otic capsule and possible development of a labyrinthine fistula; the latter is almost always associated with cholesteatoma but may also occur with CSOM. This process stems from bony degradation and osteitis leading to erosion of the labyrinthine capsule mostly affecting the lateral semicircular canal. However, other semicircular canals, the vestibule, or the cochlea can be affected as well. affected individuals can present with vestibular symptoms including intermittent vertigo, imbalance, and disequilibrium, but most maintain normal equilibrium. Symptoms of the cholesteatoma are in many cases the presenting symptoms, and additional vestibular symptoms should raise suspicion. A fistula test using pneumatic otoscopy can be performed, looking for evidence of deviation of the eyes away from the side of pneumatic compression as a positive test. Noncontrasted CT scan can help in diagnosis with evidence of bony erosion. Management involves surgical intervention for eradication of the cholesteatoma and closure of the fistula.

Sinus cholesteatomas (posterior mesotympanic cholesteatomas) can sometimes lead to facial paralysis as a potential complication. The pathways of disease progression make this more likely with sinus cholesteatomas than with other types.

Rarely seen since the advent of modern medicine, erosion of the tegmen tympani or the mastoid tegmen may lead to development of a cerebral herniation or possible dural involvement with potential cerebrospinal fluid (CSF) leak. Also, thrombosis of the sigmoid sinus and intracranial abscess formation are feared complications of cholesteatoma.

Management

Once a diagnosis of cholesteatoma has been made there are few scenarios in which a nonsurgical approach is the treatment chosen. Patients with multiple comorbidities who are poor surgical candidates can be managed with routine cleaning and debridement in the office and home instillation of otic antibiotic suspensions, similarly to CSOM. Steroid additives can also be used for granulation tissue control. Patients with disease in their only hearing ear may defer surgery. Otherwise, however, surgical management of cholesteatoma is the treatment of choice. Often, multiple procedures may be necessary and the patient should be informed about the relevance of the canal wall. In some cases, certain cholesteatoma locations provide sound conduction and surgical intervention with excision of disease can result in worse postoperative hearing. Therefore, patients should be counseled about the fact that tympanomastoid surgery (see Chapter 5, p. 310) might result in a hearing loss rather than in improved hearing. Staged ossiculoplasty is optional (see p. 306), and with canal wall up procedures in which a second look procedure becomes necessary, the latter is often combined with efforts to restore hearing.

Recommended Reading

Jackler RK. The surgical anatomy of cholesteatoma. Otolaryngol Clin North Am 1989;22(5):883–896

Tos M. Incidence, etiology and pathogenesis of cholesteatoma in children. Adv Otorhinolaryngol 1988; 40:110–117

Complications of Otitis Media

Definition

Thankfully, complications of acute and chronic otitis media have become a rare event. Nevertheless, unrecognized, poorly managed, or resistant infections can potentially lead to such complications. These have to be subdivided into intra- and extratemporal complications, and despite their rare occurrence detailed knowledge is fundamental.

Closely Related Topics

• Acute otitis media and otitis media with Effusion—see p. 126

• Chronic suppurative otitis media (CSOM)—see p. 130

• Cholesteatoma—see p. 136

Introduction

Chronic otitis media is thought to result from continued inflammation or unresolved Effusion whether the Effusion was purulent, serous, or mucoid. Chronic suppurative otitis media (CSOM) with cholesteatoma presents a unique clinical and surgical challenge. This can lead to frustration both on the patient’s part and on the health-care professional’s part. These situations are frequently difficult to manage. The often frustrating nature of chronic middle ear disease in combination with the complex anatomy of the middle ear and its proximity to vital structures allows for easy spread of infection with potential for serious complications.

Pathophysiology and Classification (Fig. 4.10A)

When discussing otitis-related complications, one should realize the differences between acute and chronic infections of the tympanomastoid compartment. Specifically, acute otitis media is primarily an infection of the middle ear space with subsequent co-infection of the mastoid. Chronic otitis media, in contrast, is primarily an infection of the mastoid, which results in chronic co-infections of the middle ear.

Thus, CSOM is defined as a continuous cycle of infection, inflammation, granulation, and ulceration in the presence of a tympanic membrane perforation. Sequelae of the ongoing inflammation can lead to accumulation of granulation tissue and debris within the ear and subsequent blockage of aeration of the middle ear and mastoid cavity. This blockage of mastoid aeration often leads to growth of Gram-negative bacteria as well as an anaerobic bacterial flora. A chronically draining ear in the setting of a pressure equalization (PE) tube presents an additional challenge. Biofilms will often form on top of the tube, which acts as a foreign body. Frequent topical anti-infectious ear-drop applications increase the incidence of fungal superinfections and Pseudomonas aeruginosa colonization. Sometimes methicillin-resistant Staphylococcus aureus (MRSA) can be isolated.

In summary, the combination of an under-aerated tympanomastoid compartment with the presence of granulation tissue provides an ideal medium for bacterial proliferation in chronic ear disease. The polymicrobial nature of these infections further complicates management. Also, several host factors such as a compromised immune system, malnutrition, poor hygiene, living in overcrowded surroundings, poor personal hygiene, and limited access to health care seem to play a substantial role in the development of complications.

Bony destruction comes from enzymatic and chemical digestion from bacterial and host biochemical factors. These factors up-regulate osteoclastic cells and factors leading to further bone destruction and spread from the middle ear and temporal bone. Cholesteatoma formation and infection are also possible in a similar scenario with debris build-up, and will be discussed further on p. 136.

Bacteria can take several pathways from the tympanomastoid compartment and thereby spread to various adjacent structures. Based on the anatomical location of the affected structure, complications can be divided into two main categories: cranial (intratemporal) complications and intracranial (extratemporal) complications (Fig. 4.10A). In addition to direct propagation, hematogenous spread of bacteria has been described.

Epidemiology

Multiple series have shown that postauricular abscess formation is the most common cranial complication of acute otitis media (Fig. 4.10C); meningitis is the most common intracranial complication. Several clinical series have demonstrated that with chronic middle ear disease, multiple complications often occur at the same time. However, the antibiotic era has substantially affected the incidence of complications. Also, the need for mastoidectomy for acute mastoiditis has decreased markedly (see p. 295).

Fig. 4.10 A–F

Clinical Presentation, Diagnosis, and Management

A detailed history with assessment of the exact chronological order of events is fundamental to understanding the underlying pathology. Previous anti-infectious treatments should be considered and a thorough neurologic examination is essential once a complication is suspected. A neurotologic examination with otomicroscopy is fundamental, as is a brief audiologic evaluation. If this is unavailable at the time of admission, tuning fork testing should be done.

Patients with intracranial complications sometimes present with mental status changes, lethargy, or even coma. Often, however, mental status changes are quite subtle and do not correlate with clinical or radiographic findings. The core body temperature should be monitored frequently in an in-patient setting.

Each patient should also receive a laboratory examination (CBC with differential) and a contrasted CT scan to rule out intracranial abscess formation. A gadolinium MRI will often provide more detailed information on CNS pathology and should be considered. With suspected meningitis, a lumbar puncture (LP) is mandatory. Naturally, increased intracranial pressure should be ruled out prior to the LP.

All complications listed below will in most instances require cortical mastoidectomy, PE tube placement, and medical treatment with broad-spectrum antibiotics. These measures should occur concurrently and in a timely fashion in an in-patient setting.

Abscess Formation (Fig. 4.10C)

Bezold abscess occurs from bony erosion of the mastoid bone tip, allowing infection of the soft tissues around the neck, namely, beneath the sternocleidomastoid. Patients will present with a high neck mass, mimicking lymphadenopathy, fever, and otorrhea. If history and physical examination are unrevealing, contrast-enhanced CT and fine-needle aspiration can aid in the diagnosis. Treatment consists of incision and drainage, mastoidectomy with possible drain placement, as well as PE tube placement. Subperiosteal abscess (posterior auricular abscess) is the most common complication of COM (Fig. 4.10C), and similar in mechanism to a Bezold abscess, with erosion from osteitis into the postauricular soft tissues. Patients classically present with a mass behind the ear, displacing the auricle anteriorly, with inferior and lateral displacement as well.

Mastoiditis

Mastoiditis can be seen in the setting of AOM or COM and can be classified as acute, coalescent, or chronic. Details will be discussed in Chapter 5, p. 295. Persistent inflammation and infection lead to loss of mastoid air cell septae and a purulent fluid-filled cavity. CT is the imaging modality of choice to visualize the loss of mastoid septae. In all cases, treatment is the same with mastoidectomy and PE tube placement in addition to the broad-spectrum antibiotics.

Labyrinthine Complications and Facial Nerve Injury

Labyrinthitis can present from AOM and COM progression into the fluid space of the labyrinth through access points such as congenital labyrinthine deformities, the round and oval window, and temporal fractures or fistula tracts. Patients will have vertigo, hearing loss, and disequilibrium. The diagnosis of labyrinthitis can be made clinically in the setting of vertigo and SNHL. Treatment consists of supportive measures, antibiotics, and systemic steroids.

As with other complications, mastoidectomy is usually necessary to remove the nidus of infection. Labyrinthectomy should be avoided whenever possible. Bony dehiscences of the tympanic segment typically predispose to facial nerve involvement. Surgical mastoidectomy is often sufficient but some authors have discussed decompressive procedures. The typical site of the lesion, however, is different from that in Bell palsy (see p. 320)

Petrous Apicitis (Fig. 4.10E)

Petrous apicitis most commonly presents with deep or retroorbital pain in the distribution of the trigeminal nerve from irritation of the trigeminal ganglion within Meckel’s cave, or even paralysis of the abducens nerve within Dorello’s canal. Combined with otorrhea, this triad of symptoms is called Gradenigo syndrome (Fig. 4.10E). Treatment consists of intravenous antibiotics directed at COM pathogens, and if necessary surgical drainage as described on p. 381.

Intracranial Complications (Fig. 4.10B, D)

Meningitis is the most frequently encountered intracranial complication of both acute and chronic otitis media; see p. 231 for details. Intracranial abscess formation (epidural abscess, cerebellar abscess, temporal lobe abscess) is a feared complication that can present with focal neurologic signs. Most abscess cavities can be surgically accessed through the mastoid. Drainage procedures should be performed in conjunction with neurosurgery.

Thrombosis and abscess formation of the sigmoid sinus result from erosion of the bony wall of the sinus and subsequent clot formation (Fig. 4.10B, D). Retrograde clot propagation into the transverse sinus and even beyond has been described and is associated with great morbidity and mortality. Clinically, a picket fence fever pattern is typical and some patients present with signs of intracranial hypertension (see p. 235). An ophthalmologic examination should be performed to rule out papilledema and imaging studies can provide direct visualization of the abscess.

Management of lateral sinus thrombosis has been controversial. Some authors recommend long-term anticoagulation, whereas others prefer surgical decompression of the sigmoid sinus. Most clinicians agree, however, that a cortical mastoidectomy and broad-spectrum antibiotics are the minimum treatment requirements.

Prognosis

Patients with complications from chronic otitis media can present as systemically ill, and early diagnosis and urgent intervention are necessary in many instances. Healthy relationships with the neurosurgical service can aid the patient in obtaining timely care, which is seen as the major determinant in limiting morbidity and mortality from the complications discussed previously.

Recommended Reading

Goldstein NA, Casselbrant ML, Bluestone CD, KursLasky M. Intratemporal complications of acute otitis media in infants and children. Otolaryngol Head Neck Surg 1998;119(5):444–454

Sheehy JL, Brackmann DE. Cholesteatoma surgery: management of the labyrinthine fistula—a report of 97 cases. Laryngoscope 1979;89(1):78–87

Temporal Bone Encephalocele

Definition

An encephalocele describes herniation of meninges and/or brain tissue through a defect in the skull base. In the temporal bone the site of the defect is typically located in the floor of the middle cranial fossa, occasionally in the posterior fossa wall. The two primary sites in the floor of the middle fossa are the tegmen tympani and the tegmen mastoideum.

Closely Related Topics

• Chronic suppurative otitis media (CSOM)—see p. 130

• Increased intracranial pressure—see p. 235

• Middle fossa approach–see p. 338

Introduction and Pathogenesis (Fig. 4.11A)

A temporal bone encephalocele is a herniation of intracranial contents through a defect in the bony tegmen (Fig. 4.11A). In general, encephaloceles can be classified as either acquired or spontaneous. Acquired encephaloceles are most commonly due to chronic otitis media with or without cholesteatoma or are due to their surgical treatment (iatrogenic). Other causes include trauma, neoplasm, irradiation, or inflammatory conditions.

Spontaneous encephaloceles may be congenital or may result from increased intracranial pressure. The exact mechanism of this disease process is not entirely understood. However, spontaneous encephaloceles are commonly observed in morbidly obese patients and require careful consideration of comorbidities, especially when surgical intervention is planned.

Clinical Presentation

The clinical presentation of temporal bone encephaloceles is generally mild, with symptoms of serous otitis media, aural fullness, conductive hearing loss, and cerebrospinal fluid otorrhea or rhinorrhea (through the eustachian tube). However, life-threatening complications such as meningitis, brain abscess, temporal lobe seizures, or intracranial air can occasionally serve as sentinel events.

Diagnosis (Fig. 4.11B)

The diagnosis of temporal bone encephaloceles requires a high degree of clinical suspicion in any adult patient with unilateral middle ear Effusion or watery otorrhea in the absence of an identifiable otologic disease. Definite diagnosis requires the appropriate radiologic work-up. High-resolution computed tomography can define anatomical relationships as well as the site and extent of osseous destruction (Fig. 4.11B). Small dehiscences of the tegmen may not be apparent on axial CT, as the tegmen lies parallel to the axial projection, making it necessary to use coronal planes. However, the more detailed nature of a soft-tissue mass cannot be defined by CT alone, necessitating MRI. On MRI, dural herniation is indicated by the presence of a protruding low-signal mass that is bordered by high-signal CSF on T2-weighted images. On gadolinium-enhanced T1-weighted images, brain tissue is herniated and the surrounding meninges are enhanced (Fig. 4.11B). When the presence of a CSF leak is questionable, beta-2-transferrin testing can be performed.

Management (Fig. 4.11C, D)

The management of temporal bone encephaloceles is primarily surgical. The goals of surgical intervention include the management of the herniated cranial contents, the occlusion of the bony defect, and restoration of the conductive hearing apparatus. Encephaloceles can be approached via a transmastoid approach, via the middle cranial fossa, or via combined approaches.

If the tegmen defect is smaller than 1 cm in diameter, the repair can be preformed via a transmastoid approach with a temporalis muscle fascia repair. Typically, however, the defect is larger than 1 cm and is best addressed via the middle fossa approach and exposure of the defect from superior aspect (Fig. 4.11C). Here, a typical middle fossa craniotomy measuring ~5 cm × 5 cm is created with the anterior-posterior aspect centered at the zygomatic root. The dura is elevated from the lateral surface of the temporal bone. Further elevation should be performed from posterior to anterior with preservation of the greater superficial petrosal nerve (GSPN). This structure typically exits its bony canal at the facial hiatus close to the geniculate ganglion. In contrast to a standard middle fossa approach used for vestibular schwannoma surgery, the geniculate ganglion can be dehiscent within the surface of the middle fossa. Also, dural elevation is complicated by brain herniation. Often, the herniated brain tissue has to be amputated since it is nonfunctional.

Fig. 4.11 A–D

The bony defect should be entirely exposed to allow for adequate repair. Several methods and materials have been used to facilitate reconstruction. Mostly, surgeons use full-thickness or partial-thickness (lamina interna) temporal squama to achieve bony reconstruction. Most often, a fascia graft is used to provide a membranous seal. The craniotomy is closed in a usual fashion (Fig. 4.11D).

Prognosis

Despite the mostly straightforward technique of the surgical intervention, the postoperative course can be complicated substantially. It is believed that the repair of some spontaneous encephaloceles can results in pathologic CSF flow patterns and hydrocephalus. However, other intracranial complications have been observed and the clinician should be advised to proceed carefully. A middle fossa craniotomy with multilayered closure is used by most clinicians as this approach provides adequate exposure for reconstruction. The placement of a lumbar drain is dependent upon surgical preference and the patient’s underlying pathology.

Recommended Reading

Gubbels SP, Selden NR, Delashaw JB Jr, McMenomey SO. Spontaneous middle fossa encephalocele and cerebrospinal fluid leakage: diagnosis and management. Otol Neurotol 2007;28(8):1131–1139

Neoplasms of the Middle Ear

Neoplasms of the temporal bone can be derived from the multitude of germinal layers that the temporal bone originates. Technologic and surgical advancements have allowed for temporal skull base surgery to take tumors that were once unresectable and make them not only approachable but at times amenable to curative resection. Other tumors will require radiation, watchful waiting, or combined approaches. By mass effect a large benign lesion within the confines of the middle ear can be more detrimental than a small malignant lesion.

Benign Neoplasms of the Middle Ear

Definition

Paragangliomas are by far the most common benign lesion of the middle ear. When arising within the tympanic cavity they are termed glomus tympanicum tumors, and should be distinguished from glomus jugulare tumors described elsewhere (p. 212). For most lesions, surgical excision is the treatment of choice but might be complicated by the complex anatomy of the tympanomastoid compartment. A close interdisciplinary collaboration is often required to provide optimal clinical outcomes.

Closely Related Topics

• Lesions of the jugular foramen—see p. 212

• Benign tumors of the external auditory canal—see p. 117

• Tympanomastoid procedures—see p. 310

Nonglomus Tumors of the Tympanomastoid Compartment

Introduction

Benign tumors of the middle ear and temporal bone are rare and have been described using many different terms, with carcinoid tumor and middle ear adenoma being the most accepted of all neuroendocrine lesions. Others have described them as adenomatous tumor of the middle ear, adenocarcinoid, and amphicrine tumor. But the difficulty differentiating these tumors as separate entities has led to extensive debate in the literature.

Pathophysiology and Epidemiology

Middle ear adenomas are benign neuroendocrine tumors thought to arise from the middle ear mucosa. They are seen in all ages with no predilection for age or sex. Adenomas can differentiate into a multitude of patterns including solid, glandular, or trabecular architecture, which can make diagnosis and classification difficult. Carcinoid tumors behave in a similar fashion both clinically and histologically. The tumors are distinguished from one another by immunohistochemical staining.

Adenomas, although benign, can erode through bone and have serious sequelae within the middle ear, including cranial nerve involvement. Choristoma is another extremely rare benign lesion involving the middle ear and temporal bone, which most commonly arises from ectopic normal salivary tissue within the middle ear. Choristomas are most often intimately involved with the facial nerve as it courses through the middle ear and temporal bone, and can be sessile or pedunculated. Hemangiomas and vascular malformations can also occur in the middle ear space, and although rare, the majority arise from vascular derivatives surrounding the IAC and geniculate ganglion (see p. 320).

Clinical Presentation (Fig. 4.12A)

Patients usually present with symptoms mimicking chronic otitis media (COM) or cholesteatoma with hearing loss, possibly otorrhea, and pain (Fig. 4.12A). On examination there may be a visible mass behind the TM. Carcinoid tumors may also present with hearing loss, but ossicular involvement is not typical, and carcinoid syndrome has only been reported once from middle ear carcinoid tumors. Choristomas, hemangiomas, and vascular formations could present with facial nerve involvement, given the propensity of these lesions to involve the facial nerve and geniculate ganglion, respectively.

Diagnosis

Most often these tumors are diagnosed during or after the surgical resection, instead of preoperatively. In some instances the presentation may necessitate CT imaging to outline bony margins or detect bony destruction. MRI may be useful if intracranial involvement is suspected. MRI with contrast will reveal enhancement on the T1-weighted sequences in the case of hemangioma, with characteristic bony spiculae interspersed.

Management

Adenomas, although benign, necessitate surgical resection. Lesions with neural involvement have been shown to carry a poorer prognosis. Unless malignancy is grossly evident, nerve-sparing treatment is considered the standard of care. The surgical approach depends on the size of the tumor, which can be aided by imaging studies. In general, smaller tumors may be approached through a transcanal or endaural technique, while a larger tumor might necessitate a transmastoid approach (see p. 310).

Fig. 4.12 A–G

Malignant lesions (see p. 151) may require (sub) total temporal bone resection (see p. 280). Radiation has had little impact on adenomatous tumors, and the tumors are considered to be quite radio-resistant. Carcinoid tumors of the middle ear are treated in a similar fashion with complete excision. Choristomas are classically observed with serial examinations since they are not considered true neoplasms and lack malignant potential. In addition, their intimate relationship with the facial nerve is often problematic during excision. Hemangiomas may be resected as well, but facial nerve dysfunction is a likely possibility.

Glomus Tympanicum Tumors

Introduction

Glomus tumors are relatively uncommon benign neoplasms, but are the second most frequently diagnosed neurotologic neoplasm behind vestibular schwannomas. (Refer to p. 212 for glomus jugulare tumors.) Regardless of their origin, paragangliomas are identical in histologic appearance, yet the distinction between glomus jugulare, glomus vagale, and glomus tympanicum must be made when considering medical and surgical management.

Pathophysiology (Fig. 4.12B, C)

Paragangliomas of the middle ear arise from neural crest origins, with glomus tympanicum developing along the nerve of Jacobson (CN IX) or Arnold’s nerve (CN X) if the tumor is located within the middle ear cavity (Fig. 4.12B). Histologically, the classic paraganglioma will produce a cluster of chief cells, surrounded by vascular structures, referred to as a Zellballen pattern (Fig. 4.12C). Although classified as benign, glomus tympanicum’s location within the middle ear allows for significant spread along paths of minimal resistance, including bony destruction. Like other paragangliomas, glomus tympanicum has the potential for malignant transformation, but this is very rare.

Clinical Presentation and Diagnosis (Fig. 4.12D–G)

Patients with glomus tympanicum neoplasms may present with symptoms of a mass effect within the middle ear, ossicular destruction leading to hearing loss, or bony erosion of the skull base leading to more serious sequelae (see Fig 4.12D for staging). Pulsatile tinnitus is the most common manifestation, followed by hearing loss, aural fullness, otalgia, and in some instances vertigo. Most notably, patients may be asymptomatic or present with systemic signs from functional tumors secreting vasoactive catecholamines (Fig. 4.12E). On physical examination, a vascular mass may be noted behind the tympanic membrane with redness of the tympanic membrane that blanches with positive pressure from pneumatic otoscopy (Fig. 4.12F). A full cranial nerve examination should be performed to investigate for possible involvement of CN VII, IX, and X to aid in estimation of tumor extension. CT and MRI often are diagnostic and mandatory in the diagnosis of these tumors. CT can show the extent of bony destruction and may help to distinguish glomus jugulare from glomus tympanicum or other lesions (Fig. 4.12G).

Treatment

The therapy for glomus tumors has been controversial; however, in the case of limited glomus tympanicum tumors, surgical management has been the primary treatment with radiation for palliation or larger lesions. Specific to the glomus tympanicum, a transcanal approach can be used for small masses entirely limited to the mesotympanum. Otherwise, for tumors outside the confines of the mesotympanum, a transmastoid approach is needed and can include hypotympanotomy approach, or mastoid with an extended facial recess. In some cases an infratemporal fossa approach may be necessary when the tumor erodes anteriorly into the petrous carotid artery (see Chapter 5, p. 377)

Recommended Reading

Gulya AJ. The glomus tumor and its biology. Laryngo-scope 1993;103(11 Pt 2, Suppl 60):7–15

Jackson CG, Glasscock ME III, Harris PF. Glomus tumors. Diagnosis, classification, and management of large lesions. Arch Otolaryngol 1982;108(7):401–410

Malignant Neoplasms of the Middle Ear

Definition

Malignant neoplasms of the middle ear are rare, with the most common tumors including squamous cell carcinoma (SCC), basal cell carcinoma, adenoid cystic carcinoma, rhabdomyosarcoma, and Langerhans histiocytosis X (LHX). Management of lesions involving the temporal bone continues to be a challenging and debatable topic within neurotologic surgery. Significant progress has been made, however, despite the absence of a universally accepted clinical algorithm.

Closely Related Topics

• Malignant neoplasms of the external ear—see p. 120

• Temporal bone resections for malignant disease—see p. 280

• Infratemporal fossa approaches—see p. 377

Introduction (Fig. 4.13A)

Malignant tumors of the temporal bone are rare and account for less than 0.2% of all tumors of the head and neck. Given the rarity of these tumors, the diagnosis, treatment, and staging are not universally well established. The most common primary malignant cancer of the temporal bone is squamous cell carcinoma (SCC) and much of the management and therapies of temporal bone malignancies are based on experience obtained with SCC of the external ear. The complex anatomy of the temporal bone makes tumor spread difficult to predict and, in combination with the delayed presentation and diagnosis, surgical management becomes difficult. So far, the literature does not separate malignancies of the EAC (see p. 108) from primary tumors of the middle ear. Hence, much of the data referred to within this section include malignancies of both the EAC and the middle ear. A list of malignant tumors of the temporal bone is shown in Fig. 4.13A.

Pathophysiology (Fig. 4.13B)

The origin of SCC of the temporal bone is not well established. Series dating from 1908 to the present have drawn conclusions about various etiologic factors including radium exposure, other radiation, chronic otitis media, cholesteatoma, and chronic osteomyelitis of the temporal bone. The common pathway of chronic inflammation and irritation can lead to SCC or human papilloma virus (HPV) associated SCC, possibly due to a viral upper respiratory infection (URI) introduced to the middle ear via the eustachian tube. When neoplasms of the skin or the conchal bowl involve the EAC, they can both spread into the soft-tissue planes of the head and neck due to their nominal resistance to tumor spread (Fig. 4.13B). Tumor spread to the temporomandibular joint and masticator space can occur along bony–cartilaginous junctions or through the fissures of Santorini. These patients often present after many years of symptoms, with nodal disease present in up to 20% of patients.

The origin of adenoid cystic carcinoma within the middle ear space as a primary tumor is debatable. This tumor has a predilection for perineural invasion and intracranial involvement with late metastasis, which is identical to a primary tumor of the salivary gland. Langerhans histiocytosis classically consists of sheets of Langerhans histiocytes mixed with other inflammatory cells such as eosinophils and multinucleated giant cells (Fig. 4.13C). The disease exists in a spectrum that includes Hand–Schüller–Christian disease, eosinophilic granuloma, and the most aggressive form, Letter–Siwe. The skeletal lesions can involve the temporal bone with erosion into the mastoid or lumen of the ear canal.

Clinical Presentation

The most common presenting symptoms include chronic otorrhea and hearing loss. With disease advancement, otalgia and otorrhagia will occur. The symptomatology can easily be misinterpreted as chronic otitis media, and therefore overlooked. The presence of blood-stained otorrhea after a thorough treatment trial is highly suspicious for a neoplastic process. Physical examination findings include otorrhea, a probable mass lesion on otoscopy, facial swelling, and cranial nerve involvement (most likely CN VII). Facial nerve involvement may first manifest as facial spasms due to invasion of the perineurium, before onset of weakness or paralysis. The route of spread of temporal bone tumors could also lead to trismus from invasion of the temporomandibular joint (TMJ).

Hearing loss is most often conductive from the associated chronic inflammatory process within the tympanomastoid compartment. Also, more extensive lesions can invade the EAC and obstruct the lumen. Invasion into the labyrinth can lead to SNHL and balance disturbance. Langerhans histiocytosis X (LHX) can present with painful swelling, cervical lymphadenopathy, and a rash.

Fig. 4.13 A–C

Diagnosis

In addition to a full physical head and neck examination, audiometric testing should be done as part of a baseline evaluation. Biopsy of any visible mass within the EAC should be sent for full histopatho-logic work-up. With LHX, simple radiographs of the skull can show the classic bony involvement. The use of fine cut (1 mm) temporal bone CT is the initial study of choice for evaluation of bony erosion along the planes of spread discussed above. Evaluation of the neck with CT is needed to rule out inferior spread or lymph node involvement. The soft-tissue component may be difficult to delineate in the case of long-standing inflammation or the absence of bony erosion, and MRI with gadolinium may be done. Also in the case of suspected neural involvement, parotid involvement, or intracranial spread, MRI with gadolinium would be superior. In the event of carotid involvement (petrous portion) or expected intensive resection, carotid angiography with trial balloon occlusion would be recommended to evaluate the ability of the contralateral carotid to adequately maintain cerebral blood flow. In addition, the contralateral venous outflow tract should be evaluated in the case of ipsilateral sigmoid sinus or internal jugular vein sacrifice.

Staging

The only accepted TNM staging criteria for temporal bone malignancies was proposed by Arriaga and colleagues at the University of Pittsburgh (see p. 120). However, this system is based on external auditory canal malignancies and not primary neoplasms of the middle ear. Nevertheless, several prognostic conclusions can be drawn. Specifically, it appears that promontory or facial nerve involvement is a negative prognostic marker.

Management

Operative management remains controversial regarding how radical a procedure is necessary. Surgical excisions of middle ear and temporal bone malignancies can vary in their level of temporal bone resections (see p. 280). Radiation alone has been shown to be mostly ineffective, especially for long-term survival. Conversely, postoperative radiation has demonstrated beneficial effects on survival. With postoperative radiation, the mastoid cavity can be obliterated (see p. 310) at the time of the operation to avoid osteoradionecrosis. It is agreed that all patients able to tolerate surgery should undergo surgery, with the exception of those affected by histiocytosis X, which is treated primarily with radiation and sometimes adjuvant chemotherapy.

Prognosis

Positive surgical margins, nodal disease, and metastasis are factors associated with poor prognosis. Several authors report favorable outcomes of early-stage neoplasms, reporting an 80%–100% long-term survival rate. Later-stage cancers show a greater range in survival between 50% and 80% after adequate surgery and radiation. Advanced lesions have a poorer prognosis with 2-year survival of 0%–40%, despite aggressive treatment.

Recommended Reading

Lo WC, Ting LL, Ko JY, et al. Malignancies of the ear in irradiated patients of nasopharyngeal carcinoma. Laryngoscope 2008;118(12):2151–2155

Moffat DA, Wagstaff SA, Hardy DG. The outcome of radical surgery and postoperative radiotherapy for squamous carcinoma of the temporal bone. Laryngoscope 2005;115(2):341–347

Moody SA, Hirsch BE, Myers EN. Squamous cell carcinoma of the external auditory canal: an evaluation of a staging system. Am J Otol 2000;21(4):582–588

Ramsey MJ, Nadol JB Jr, Pilch BZ, McKenna MJ. Carcinoid tumor of the middle ear: clinical features, recurrences, and metastases. Laryngoscope 2005; 115(9):1660–1666

Otosclerosis

Definition

Otosclerosis is characterized by focal remodeling of labyrinthine bone with a predilection for the oval window niche, which typically results in fixation of the stapes footplate. affected individuals first present with conductive hearing loss. With long-standing disease, however, cochlear involvement can lead to a sensorineural loss, resulting in mixed hearing loss.

Closely Related Topics

• Surgery for otosclerosis—see p. 317

• Surgery for implantable auditory devices—see p. 328

• Evaluation of hearing—see p. 53

Introduction (Fig. 4.14A)

Clinically, otosclerosis can be defined as a remodeling of the otic capsule, especially at the level of the oval window that leads to a fixation of the stapes footplate (Fig. 4.14A) and thus to a conductive hearing loss (stapedial otosclerosis). In addition, other parts of the otic capsule can be involved, resulting in additional sensorineural hearing loss (cochlear otosclerosis).

Histology (Fig. 4.14B)

Histologic changes that can be found in otosclerosis can be grouped into two different stages of the disease, the otospongiotic stage, followed by the otosclerotic stage. Otospongiotic changes involve resorption of bone by increased osteoclastic activity, angioneogenesis, and enlarged blood vessels. On a cellular level, inflammatory cells are present and there is deposition of IgG, IgA, and C3.

Otosclerotic changes are characterized by replacement of osteolytic bone and inflammatory cells by new bone formation, calcification of blood vessels, and formation of scar tissue (Fig. 4.14B). The newly formed bone may then cause fixation of the stapes footplate. Otospongiotic and otosclerotic changes can coexist within the temporal bone and most likely represent two stages of the disease. Otospongiotic and otosclerotic foci may occur in any part of the temporal bone, however, the round window niche, especially the fissula ante fenestram, appears to be a preferential site.

Pathophysiology

In our current knowledge, the etiology of oto-sclerosis is both complex and multifactorial. Pathophysiologically, it can be characterized as an abnormal remodeling of the bony otic capsule, involving bone resorption and new bone formation. Whereas normally the temporal bone has the smallest rate of remodeling in the human body, it is pathologically increased at the otospongiotic and otosclerotic foci. At present, two theories of disease encompass the most evidence:

1. Otosclerosis is caused by a reaction to a persistent measles virus infection

2. Otosclerosis is based on a genetic predisposition with multigenetic inheritance

Evidence that favors the theory of a persistent measles virus infection includes the discovery of measles virus particles in osteoclasts in oto-sclerotic lesions, and increased IgG levels against measles virus within the perilymphatic fluid and osteosclerotic foci. More recently, phenotyping of the measles virus in otosclerotic lesions has been performed successfully. Interestingly, specific types of the measles virus have been found and the viral types identified were prevalent decades earlier and are not currently in circulation, thus indicating a long-term intracellular homing of the virus. In addition, epidemiologic studies suggest a decreased incidence of otosclerosis following the introduction of general vaccination against the measles virus.

Genetic causes of otosclerosis have been proposed for several decades. They are primarily based on the observed increased incidence in some families, implying a hereditary pathway with autosomal dominant inheritance and incomplete penetrance in affected families. More recently, linkage analyses in families with several attained members have revealed an increasing number of gene loci (named OTSC 1–5) linked to clinical otosclerosis. However, specific genes have not yet been identified at the time of this publication. Other genetic variants for collagens (osteogenesis imperfecta) and bone morphogenetic proteins have also been associated with otosclerosis.

These two theories are not exclusive, but may be concurrent in that the genetic predisposition somehow interacts with the course of the persistent measles virus infection. Hormone regulation, especially increased clinical incidence of otosclerosis after pregnancies, might be related to up-regulation of estrogen receptors.

Epidemiology

Otosclerosis can be divided into histologic and clinical subtypes. In the histologic type, otosclerotic or otospongiotic foci can be found during careful histologic examination of the temporal bone when clinical symptoms are absent, indicating that the foci have not yet caused a fixation of the footplate or a sensorineural hearing loss. In the clinical type, at least one of these symptoms has become apparent. Diagnosis of the histologic type is much more frequent than diagnosis of the clinical type. The prevalence of the histologic type is reported to be up to 6%–7% in temporal bone registries; however, in unselected temporal bones it appears to be less frequent, with 2.5% of temporal bones or 3.4% of patients.

Clinical otosclerosis has a prevalence of ~0.3%– 0.4% in Caucasians. Females are affected ~2:1 versus males in several studies. In ~50% of patients, one or more family members are also affected. The risk of clinical otosclerosis increases with age and the first signs are often apparent between 40 and 50 years of age. In the majority of patients, oto-sclerosis occurs bilaterally, but there is a time delay between ears affected, resulting in asymmetric hearing loss. A recent study suggests a diminishing incidence of clinical otosclerosis over the last few decades, possibly related to the introduction of measles virus vaccination.

Clinical Presentation (Fig. 4.14C)

• Typically, unilateral slowly progressive conductive hearing loss, which can be bilateral and presents in third or fourth decade.

• Carhart notch (typical 10–30 dB drop of the bone line at around 2000 Hz, which seems to be due to mechanical factors associated with stapes fixation). This notch is not a true indication of the bone line and it often corrects after stapedectomy (Fig. 4.14C).

• Absent stapedial reflex (p. 58).

• Generally normal mastoid pneumatization, no concurrent middle ear disease.

• Sensorineural or mixed hearing loss for otic capsule involvement.

• Disequilibrium and tinnitus are frequently observed.

• Schwartze sign (hyperemia of the promontory mucosa due to underlying bone remodeling that can be seen through the tympanic membrane as a pink hue).

Most patients with otosclerosis present with a slowly progressive hearing loss, which may be unilateral or bilateral, symmetric or asymmetric in nature. In most cases, patients do not have a history of inflammatory middle ear disease, except for occasional episodes of middle ear infection during childhood. Tinnitus in the involved ear can be a concurrent complaint. Some patients may complain about dizziness, but vestibular symptoms are less frequent and minor. There is often a strong family history of hearing loss.

Diagnosis (Fig. 4.14C–E)

• Otoscopy generally shows no pathology; however, sequelae of middle ear infections such as scars or perforation do not exclude a concurrent pathology of otosclerosis.

• Tuning fork examination: Weber and Rinne tests with typical findings indicating unilateral or bilateral conductive hearing loss. Also, a negative Rinne test (bone conduction greater than air conduction) is typically viewed as a surgical indication.

• Pure-tone audiometry (air and bone conduction thresholds): Conductive hearing loss is a typical finding in otosclerosis with a gap between air conduction and bone conduction that can range from 5 dB up to 50 dB. In addition, bone-conduction thresholds often show a distinct increase at 2000 Hz, the so-called Carhart notch. It may be attributed to a mechanical inhibition of the basilar membrane movement secondary to fixation of the footplate. It often disappears after successful surgical treatment of otosclerosis. In more extensive cases of otosclerosis, especially with a greater involvement of the otic capsule, a real sensorineural hearing loss with increased bone conduction thresholds may occur (Fig. 4.14C).

• Tympanometry and stapedius reflex measurements (ipsi- and contralateral stimulation). The tympanometric curve is normal (type A, in the absence of concurrent middle ear pathology), whereas stapedial reflexes are absent in the involved ear for both ipsi- and contralateral stimulation.

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related

Related posts:

Temporal Bone Dissection Surgical Therapy of the Temporal Bone Basic Principles Otologic and Neurotologic Diagnostics and Tests Disease-Specific Diagnostics and Medical Management Disease-Specific Diagnostics and Medical Management

Stay updated, free articles. Join our Telegram channel

Join