Anatomy and pathophysiology
The pathophysiology of acute and chronic suppurative otitis media and the progression to mastoiditis10,82,103,105 is only briefly reviewed here. The
temporal bone is intimately associated with the middle ear space by its connection through the narrow aditus ad antrum (Figure 155-5). In most cases
of uncomplicated otitis media or otitis media with effusion, evidence of inflammation into the mastoid is often shown radiographically by fluid
collection or mucosal thickening within the mastoid air cells. In a histologic study of 222 temporal bones with evidence of otitis media, 96% also had
fluid or pathologic tissue in the mastoid.96 As described, secretory cells of the middle ear are not found in the mastoid cavity. Thus, fluid in the
mastoid cavity results from otitis media, and its presence does not indicate an acute or chronic mastoiditis.
The natural progression of acute otitis media to coalescent or surgical mastoiditis follows a well-described sequence of stages.47,105 Depending on
the virulence of the infecting organism, the health of the host, and the timing of medical or surgical intervention, the disease process can be reversed
at any stage. Because of the continuity of the middle ear space with the mastoid cavity, all patients with otitis media exhibit some degree of mastoid
inflammation. An acute coalescent mastoiditis, however, is distinguished by the inflammatory erosion of the bony septations, which divide the mastoid
cavity into a honeycomb arrangement of air cells (Figure 155-6). Thus, the mastoid cavity becomes a cistern of purulent material and ongoing
First, hyperemia and edema of the mucoperiosteal lining of the pneumatized mastoid air cells obstruct the narrow additus and disrupt aeration.
Thickened mucous membrane and impaired ciliary function prevent normal drainage of the middle ear through the eustachian tube.97 The early
exudate is serous but becomes purulent as inflammatory cells accumulate. Continued inflammation, hyperemia, and accumulation of purulent debris
cause venous stasis, local acidosis, and dissolution of calcium from the bony septae. Osteoclastic activity in the inflamed periosteum softens and
removes the decalcifying bony partitions, causing the small air cells to coalesce into a larger cavity. Histologic examination shows that areas of
coalescent bone erosion are combined with adjacent areas of beginning healing by bone deposition.105 Thus, the tendency toward spontaneous
resolution is particularly striking in the stage of coalescent mastoiditis. As the acute inflammation subsides, the healing processes replace the
mucoperiosteum with maturing granulation tissue. Fibrosing osteitis appears in areas of bone destruction. With healing, the osteoplastic activity
results in the production of dense, compact bone. Chronic mastoiditis results in a sclerotic, poorly aerated mastoid cavity (Figure 155-7).
Several cases proceed from the acute stage to the subacute stage, in which active progression has been arrested, to the chronic stage. In a few
cases, one or multiple reversions to the stage of acute mastoiditis occur so that the disease should be considered.47
In the pre-antibiotic era, acute coalescent mastoiditis was a complication of acute otitis media in 25% to 50% of cases.64 By the 1940s, the use of
sulfonamides significantly reduced the number of deaths from potentially lethal complication and reduced the mortality rate to 3%, although the
reported incidence of acute mastoiditis had not changed.11,79 Introduction of penicillins and broader spectrum antibiotics altered the natural course of
otitis media. In 1946, House46 showed that the use of sulfonamides alone decreased the incidence of mastoidectomy by two thirds.46 The reported
rate of a surgical mastoiditis developing from acute otitis media was 0.3% to 6% in the 1950s4,71 and 0.02% to 0.004% in the 1980s.73,80
Four studies, however, reported an increase in the incidence of acute mastoiditis.26,45,51,89 A study of children with acute mastoiditis noted that the
incidence (P < 0.05) in the number of children managed significantly increased from 1975 to 1979 (1.4 patients per year) to 1987 to 1992 (4.2
patients per year).45 The authors identified several predisposing factors for the development of acute mastoiditis, including withholding antimicrobials
for the management of acute otitis media, using suboptimal drugs for therapy (penicillin and erythromycin), and managing for insufficient duration. A
study of 27 cases of mastoiditis between 1985 and 1988 reported a threefold increase in the incidence of acute mastoiditis compared with that in the
preceeding 15 years.26 More than half of the patients had no history of infection before the episode of acute mastoiditis. Half of the patients had
been adequately managed with antibiotics. The authors could not determine the reason for the increase in the number of cases of acute mastoiditis.
The bacteriology of acute mastoiditis is slightly different than that of acute otitis media. Most studies report pneumococci and group A streptococci
as the most frequently isolated pathogens in mastoiditis,26,32,41,65,74 whereas the more resistant H. influenzae, the second most common pathogen
in acute otitis media, is rarely found .
Bacteriologic examinations were performed on surgical aspirates from 29 children who underwent mastoidectomy between 1970 and 1989. Slightly
different results were observed between the children who were managed with antibiotics before admission (n = 15) and those who were not (n =
14). In patients not given antibiotics, pneumococci or b-hemolytic streptococci were isolated in 71%. No isolates of H. influenzae or M. catarrhalis
were found. In patients managed with antibiotics, no isolates of b-hemolytic streptococci were found; the organisms were pneumococci and H.
influenzae. Also, no organisms were isolated in 49% of the cultures.80
In a study of 28 mastoid cavity operative specimens, cultures of only 20 yielded 22 organisms. S. pneumoniae (n = 13, 65%) was the most common
isolate, followed by Streptococcus pyogenes (n = 4, 20%), S. aureus (n = 2, 10%), coagulase-negative staphylococcus (n = 2, 10%), and E. coli (n
= 1, 5%). Two of three isolates of S. pyogenes were from patients managed with penicillin.45
Ginsberg and others32 reported that although H. influenzae is one of the more common isolates from acute otitis media, it has a predilection for
mucous membranes and is less likely to invade bone, possibly explaining the infrequency of isolates from mastoidectomy cultures.32
Acute coalescent mastoiditis
Classically, acute coalescent mastoiditis forms approximately 2 weeks after the onset of otorrhea.106 The symptoms are very similar to those of
acute suppurative otitis media, but they do not warrant surgery when they occur early in a middle ear infection. However, if they persist or recur
after several weeks from the onset of acute otitis media, particularly in a patient managed with appropriate antibiotic therapy, an evolving coalescent
mastoiditis should be considered.33 The time at which symptoms and signs appear is more important than their severity in evaluating the need for a
mastoidectomy in acute suppurative otitis media.
Symptoms of acute coalescent mastoiditis include otorrhea for more than 2 weeks, persistent fevers, persistent or recurrent pain behind the ear,
erythema, edema, tenderness over the mastoid process, and sagging of the posterosuperior meatal wall resulting from thickening of the periosteum of
the osseous meatus adjacent to the antrum (Box 155-2). The tenderness over the mastoid is the most consistent physical sign of coalescent
mastoiditis. The tenderness is greatest where the trapped pus is nearest to the periosteum; in adults, this is over the tip of the mastoid process, but in
children with incomplete pneumatization, the tenderness is more often over the fossa mastoidea near the antrum.33 This shallow depression is
approximately 1 cm posterior to the spine of Henle, where the cortex is perforated by numerous blood vessels.
Radiologically, the clouding of the mastoid seen with acute otitis media evolves into a loss of distinct bony partitions as decalcification and
osteoclastic bone removal occur. Before routine computed tomography (CT) of the mastoid, serial mastoid films were compared to show the
progressive bone changes of coalescence. Although any of these symptoms may present in varying degrees of severity, the presence of one or a
few symptoms may alert the physician to coalescent mastoiditis. Rarely, the otorrhea may cease, yet a walled-off abscess may remain within the
mastoid cavity to cause persistent symptoms and radiographic changes. This arises with petrous apex extension or in acute otitis media inadequately
managed by antibiotics.
Although the incidence of surgical mastoiditis appears to be decreasing, several authors continue to stress the need for a high index of suspicion of
acute mastoiditis in children with otitis media that could be masked by antibiotic therapy.12,44,86,126,127 Even with the advent of antimicrobial therapy
for the management of acute otitis media, otitis media should still be considered a potentially dangerous disease because the clinical course is less
predictable than in the past. Review of the literature reveals that 36% to 72% of patients with acute mastoiditis developed the disease despite prior
Acute mastoiditis has frequently been reported in patients with a well-aerated tympanic cavity and normal appearing tympanic membrane. Many
authors in the last 2 decades have called this masked mastoiditis and attribute it to inadequate antibiotic management of acute otitis media.43,92 The
clinical course is more insidious than that of classical coalescent mastoiditis. In a recent review, 72% of 18 patients with acute mastoiditis had no
history of ear disease, and 67% had middle ear symptoms for less than 7 days before developing a clinically significant mastoiditis.60 In another
study, 28% of 57 children managed for acute mastoiditis had a history of acute otitis media, and only 60% had an episode of acute otitis media in the
4 weeks before the development of acute mastoiditis. In addition, 40% had a normal appearing tympanic membrane when they presented with acute
Antibiotic management for acute otitis media cannot be considered as an absolute safeguard against acute mastoiditis or against otogenic intracranial
or intratemporal complications.
Management of acute mastoiditis remains controversial. In the pre-antibiotic era, acute mastoiditis was referred to as surgical mastoiditis to
differentiate it from chronic mastoiditis. The generally accepted indications for mastoidectomy were otorrhea for more than 2 weeks, anterior
displacement of the auricle, sagging of the posterior superior canal wall, mastoid tenderness, and edema over the mastoid process. Today, many
cases of acute mastoiditis will resolve with antibiotic management alone. Hence the controversy: when should a mastoidectomy be performed for
management of acute mastoiditis (i.e., mastoid inflammation with evidence of coalescence but without cholesteatoma)?
Currently, there are two approaches to the management of acute mastoiditis. In 1980, Shambaugh and Glasscock105 advocated that the timing of the
symptoms, rather than the presence of the symptoms, is more important in determining the indication for mastoidectomy. Symptoms of acute
mastoiditis were otorrhea for more than 2 weeks, mastoid tenderness, sagging of the posterior superior meatal wall resulting from periosteal
thickening adjacent to the antrum, persistent low-grade fever, and radiologic evidence of erosion of the bony septations within the mastoid cavity.
Although Shambaugh and Glasscock105 acknowledge that many cases of acute mastoiditis will resolve with antibiotic therapy alone, they assert that
the risk of intracranial extension by bone erosion before spontaneous healing is such that surgical evacuation of the abscess cavity is indicated.
House and Crabtree47 advocated a more conservative approach to management of acute mastoiditis, asserting that the physician could initially
manage the patient with medical or surgical therapy. The indications for surgery were a draining ear for more than 2 weeks despite antibiotic
therapy, continued signs or symptoms of mastoiditis (pain, edema over the mastoid tip or the posterosuperior canal wall), radiographic loss of bony
partitions, and signs or symptoms of threatened or definite complication. In addition, House and Crabtree47 assert that if the patient shows signs of
improvement on antibiotics, surgery is not indicated.6
Three studies of acute mastoiditis grouped patients into medical or surgical therapy based on the presence or absence of a subperiosteal
abscess.41,88,89 Patients with an abscess underwent mastoidectomy. Patients with mastoiditis but no postauricular abscess were managed with
myringotomy (if the ear was not draining), decongestants, parenteral antibiotics, and close observation. In the first study, 57% (31 patients)
responded to conservative management.41 In the second, 50% (17 patients) responded to medical therapy; two patients failed to improve and
required mastoidectomy.89 In the third study, 68% (47 patients) responded to conservative management; mastoidectomy was performed in six
patients who failed to respond: four patients developed a subperiosteal abscess while on parenteral antibiotics, one developed sepsis and a zygomatic
subperiosteal abscess, and one developed signs of meningeal irritation.88
Mastoid subperiosteal abscess
The mastoid, or postauricular, abscess is the most common
subperiosteal abscess. It forms as a result of hematogenous
spread of infection through the minute vascular channels in the suprameatal (Macewen’s) triangle. When the infection erodes the outer cortex of the
mastoid tip, a subperiosteal abscess results. The auricle is displaced anteriorly and inferiorly, the postauricular crease is obliterated, and the skin over
the mastoid process is fluctuant and erythematous. The abscess may spontaneously rupture to drain through the skin (Figure 155-8). Otorrhea may
or may not be present. The patient may be toxic and febrile with systemic signs of acute illness, or the fever may be prolonged and low grade with
occasional temperature spikes. CT shows erosion of the bony cortex of the mastoid with a subperiosteal fluid collection (Figure 155-9).
The postauricular abscess is managed with myringotomy,
postauricular incision and drainage of the abscess, and complete
mastoidectomy preferably performed under a single general anesthetic in the operating room. In myringotomy, fluid is aspirated and sent for culture,
and a tympanostomy tube is placed to re-establish middle ear aeration and facilitate drainage. The postauricular abscess is opened with a
postauricular incision (Figure 155-10). The incision is carried through the subcutaneous tissues and into the periosteum, which has been separated
from the underlying bone by the purulence. Once the periosteum has been divided, pus drains through the incision and should be cultured for aerobic
and anaerobic bacteria. If the patient has a well-pneumatized mastoid cavity, an intact canal wall mastoidectomy is performed. Some surgeons assert
that, because the mastoid is poorly pneumatized in the child, a postauricular incision is all that is necessary if the patient is younger than 3 or 4 years.
Some believe, however, that performing a cortical mastoidectomy is preferred at the time the postauricular abscess is drained to prevent exposure to
a second general anesthetic should mastoidectomy be required. The wound is then thoroughly irrigated with antibiotic saline solution, and a small
rubber Penrose drain is introduced into the abscess cavity and sutured to the skin. The skin is closed loosely with widely spaced interrupted nylon
sutures to allow fluid to drain from the cavity. The drain is left in place until drainage has nearly stopped or for approximately 48 hours.
Culture-directed antibiotics should be started when sensitivity results are available. Postoperatively, intravenous antibiotics are continued until the
cellulitis resolves. The patient can be maintained on culture-directed oral antibiotics for 2 weeks postoperatively.
Zygomatic subperiosteal abscess
A zygomatic subperiosteal abscess is formed when infection in the zygomatic air cells erodes through the cortical bone at the zygoma. It presents as
a swelling above and in front of the ear and may be confused with a parotid abscess (Figure 155-11 A, B). The periosteum under the temporalis
muscle is elevated, and the upper half of the auricle is displaced from the skull by the abscess (Figure 155-12 A, B). An unusual variation of the
zygomatic subperiosteal abscess resulting from perforation of the outer cortex at the root of the zygoma into the mandibular fossa has been
reported.101 A tender, fluctuant abscess appears just in front of the tragus, with a displacement of the mandible toward the normal side so that the
teeth no longer meet in occlusion.33
Management consists of mastoidectomy with exenteration of the zygomatic air cells and drainage of the facial abscess through the postauricular
incision. Purulence from the abscess should be cultured for aerobic and anaerobic organisms. A small passive drain is left in the skin incision for
approximately 48 hours or until drainage subsides. Postoperatively, intravenous antibiotics are continued until the facial cellulitis resolves. The patient
can be maintained on culture-directed oral antibiotics for 2 weeks postoperatively.
Perforation on the medial aspect of the mastoid tip into the digastric groove (incisura mastoidea) produces a deep abscess of the neck known as
Bezold’s abscess (Figure 155-13 A, B). This unusual complication presents as a fluctuant neck mass in a patient with acute or chronic otitis media
(Figure 155-14). Management is similar to that of a zygomatic subperiosteal abscess. A mastoidectomy should be performed. The neck should be
explored for drainage of the cervical abscess. Purulence from the abscess should be cultured for aerobic and anaerobic organisms. A small passive
drain is left in the skin incision for approximately 48 hours or until drainage subsides. Postoperatively, intravenous antibiotics are continued until the
cervical cellulitis resolves. The patient can be maintained on culture-directed oral antibiotics for 2 weeks postoperatively.
Petrositis is an extension of the inflammation of the middle ear or mastoid cavity into the pneumatized cells of the petrous apex. This can occur by
direct extension through the pneumatized air cell tracts of the petrous pyramid or by thrombophlebitis through the small vascular channels of the
temporal bone. Approximately 30% of temporal bones have a pneumatized petrous apex,104 but the extent of pneumatization of the petrous bone is
not a factor in the development of petrositis.2 Because the pneumatized petrous pyramid is a direct extension of the mastoid cavity, the stages of
petrositis parallel those of mastoiditis. However, when the marrow-containing portion of the petrous pyramid becomes infected, osteomyelitis results.
The clinical picture is essentially the same. Because the petrous pyramid does not have an established drainage system as does the mastoid cavity,
spontaneous drainage of an abscess cannot occur and purulence in the petrous apex has a greater tendency toward intracranial extension .
Two groups of air cells extend into the petrous pyramid: perilabyrinthine and apical2 (Figure 155-16). These are separated by a vertical plane passing
through the axis of the modiolus of the cochlea. The perilabyrinthine region lies posterior to this plane and is further subdivided into supralabyrinthine
and infralabyrinthine areas. The supralabyrinthine area consists of air cells adjacent to the superior semicircular canal above the internal auditory
meatus, between the endolymphatic sac and the dura of the posterior cranial fossa, and through the arc of the superior semicircular canal
(subarcuate cell tract). The infralabyrinthine area consists of air cells medial to the hypotympanum and below the labyrinth and a retrofacial air cell
tract originating from the air cells near the eustachian tube. The apical area lies anterior to the plane through the axis of the modiolus and is further
divided into the hypotympanic tract medial to the ascending carotid artery, the peritubal tract around the eustachian tube, and a perilabyrinthine tract
extending from the supralabyrinthine or the infralabyrinthine areas.1 This latter group of air cells is present in approximately 15% of temporal
Gradenigo22 first described the triad of symptoms that accompany petrous apicitis in 1907. Classically, these are retro-orbital pain (from cranial
nerve V irritation), otorrhea, and cranial nerve VI paralysis. However, additional symptoms may include fever, sensorineural hearing loss, transient
facial paresis, mild recurrent vertigo, and meningismus. The patient may complain of diplopia and otalgia but neglect to mention ‘‘pain behind the
eye.’’ Usually, this symptom is elicited by direct questioning.
Surgical eradication of all diseased tissue in the petrous apex is the management of choice. Unlike acute coalescent mastoiditis, petrositis should not
be conservatively managed with intravenous antibiotics and observation because of the tendency towards intracranial extension. Surgery aims to
provide adequate drainage from the suppurative focus in the petrous apex. The easiest and safest surgical approach is systematic exploration of all
cell tracts that extend into the petrous pyramid (Figure 155-17). Complete mastoidectomy is performed. The semicircular canals are skeletonized.
The perilabyrinthine and apical groups of air cells are systematically explored, and granulation tissue or purulence is removed until dense, compact
bone is encountered. Care should be taken to thoroughly explore all suspicious air cell tracts, including those that traverse through the center of the
superior semicircular canal (Figure 155-18 A, B). Generally, granulation tissue can be followed in an air cell tract into the abscess. A currette is
useful to remove air cells and granulation tissue around hard labyrinthine bone, thus avoiding fenestration of the labyrinth with a drill.
Labyrinthinitis is an uncommon complication of acute otitis media and mastoiditis. Schuknecht98 defined the types of labyrinthitis resulting from acute
or chronic suppurative middle ear disease according to the substance or tissue that enters the perilymphatic space. They are suppurative labyrinthitis,
serous labyrinthitis, chronic labyrinthitis, and labyrinthine ossificans. Differentiation of serous labyrinthitis, suppurative labyrinthitis, and labyrinthine
fistula can be difficult preoperatively; in many cases, adequate therapy can only be instituted after surgical exploration and definitive diagnosis.
Suppurative labyrinthitis results from bacterial invasion of the inner ear from contiguous areas of the temporal bone or meninges. Serous labyrinthitis
is an irritation of the labyrinth caused by otitic or meningitic infection without bacterial invasion of the inner ear. Chronic labyrinthitis results from a
fistula of one of the semicircular canals. Labyrinthitis ossificans is otitic or meningitic sclerosis of the labyrinth in the healed inactive state after
labyrinthitis. It is a sequela of an acute process.
Serous (or toxic) labyrinthitis results from irritation of the
labyrinth by the by-products of infection and inflammation. Toxins are thought
enter the inner ear via the oval and round windows or through a fistula in the bony labyrinth. Serous labyrinthitis may be a complication of acute or
chronic otitis media; meningitis, in which case the condition may be masked by the more severe meningeal symptoms; or syphilitic or tuberculous
otitis media. It is the mechanism of the deafness of congenital syphilis.
The patient presents with vertigo, which may be transient
and recurrent over months or years; sensorineural hearing loss
may fluctuate and is less severe than that seen in purulent labyrinthitis. Nystagmus, past pointing, and falling may be present. Retention of
labyrinthine function can be shown by caloric responses and hearing tests. In the acute phase, it may not be distinguishable from purulent
labyrinthitis, except for retention of some audiovestibular function. The signs and symptoms are less dramatic than those of purulent labyrinthitis, and
the pathologic consequences in the inner ear are less destructive. Every patient with a serous labyrinthitis should be observed closely for
development of suppurative labyrinthitis, which presents as abrupt worsening of the vestibular symptoms and sudden loss of all hearing.
Management is directed toward the infectious source. If the
labyrinthitis results from acute otitis media, myringotomy and antibiotic
therapy are sufficient. If coalescent mastoiditis or chronic otitis media with possible cholesteatoma is present, a labyrinthine fistula should be
suspected and mastoidectomy should be performed.
Suppurative labyrinthitis can develop as a complication of acute
and chronic otitis media from migration of the bacteria through the
preformed pathways of the oval window, round window, and preexisting fractures of the temporal bone and from direct invasion by erosion of the
labyrinthine bone by cholesteatoma. Bacteria may traverse the cochlear aqueduct in bacterial meningitis.50 Bacterial invasion of the inner ear
produces irreversible damage to the neuroepithelium, atrophy of the stria vascularis, collapse of Reissner’s membrane, and endolymphatic hydrops. If
the patient survives without surgery, healing occurs with fibrosis and obliterative osteitis of the labyrinth and cochlea. No audiovestibular function is
The sudden onset of severe vertigo with profound sensorineural
hearing loss during an episode of acute otitis media
indicates destruction of the labyrinth. Nystagmus, past pointing, and falling toward the opposite side occur. At first, the nystagmus is toward the
involved ear, but after several days, the fast component is toward the opposite side. Vegetative symptoms such as nausea and vomiting are severe.
Fever may not be present. There may be a prodromal period of serous labyrinthitis; prostration, complete loss of hearing, and severe worsening of
vertigo indicate progression to suppurative labyrinthitis.The labyrinth, cochlea, and cranial nerve VIII may enhance on magnetic resonance imaging (MRI) .
The symptoms are most severe during the acute bacterial invasion of the labyrinth. The vertigo and nystagmus result from sudden loss of the healthy
tonic neural impulses from the involved labyrinth, without any change in the input from the healthy side. Recovery from a unilateral peripheral
vestibular lesion is attributed to the brain’s ability to compensate for the sensory mismatch by adapting to the asymmetric sensory input. This occurs
gradually as the cerebellum and brainstem integrate the conflicting information and adapt over time to a stable lesion. The severity of the symptoms
gradually lessens over the next few days, but central compensation occurs over several weeks with complete resolution of nystagmus and vertigo.
Often, the onset of purulent labyrinthitis is followed in hours or days by facial paralysis, meningitis, or both. In the pre-antibiotic era, 50% of
cerebellar abscesses secondary to chronic otitis media were labyrinthogenic.109 Although this is very unusual today, a high index of suspicion of a
cerebellar abscess in a patient with suppurative labyrinthitis should be maintained because of the existing connections between the labyrinth and the
posterior cranial fossa.
The most important aspect of management of otogenic suppurative
labyrinthitis is close and continuous observation of the patient for
symptoms and signs of intracranial extension. Broad-spectrum antibiotics are instituted, more to prevent intracranial extension than to manage
labyrinthitis.104 Some assert that management of purulent labyrinthitis in the absence of meningitis requires prompt labyrinthectomy to prevent the
development of meningitis.109 If suppurative labyrinthitis is a complication of meningitis, surgery is not indicated.
Fistulization of the labyrinth occurs most commonly as a result
of erosion of the bony covering of the lateral semicircular canal by
cholesteatoma. Rarely, a spontaneous labyrinthine fistula may be caused by syphilitic osteitis, tubercular otitis media, chronic perilabyrinthine
osteomyelitis, or a middle ear neoplasm (e.g., carcinoma, glomus jugulare tumor). However, because development of labyrinthine fistula is so
characteristic of cholesteatoma, it should be suspected even in the case of a dry, stable perforation that has been inactive for years.104 The
incidence of labyrinthine fistulas from chronic otitis media has been reported in the modern literature as 3.6% to 12.9%.72,95,108
The patient will have active or inactive chronic otitis media
for many years. The mainstay of the diagnosis, the fistula test, is
performed by application of positive and negative pressure to the middle ear with a pneumatic otoscope. A positive fistula test produces nystagmus
with the fast component toward the tested ear with application of positive pressure, and away from the tested ear with application of negative
pressure. The nystagmus results from motion of the soft tissue over the fistula; positive pressure causes ampullofugal movement of endolymph
(away from the ampulla), and negative pressure causes ampullopetal movement of the endolymph (toward the ampulla). With a fistula of the lateral
semicircular canal (more common), the nystagmus is always horizontal. With a fistula of the superior or posterior canal, the nystagmus is vertical.
With a large anterior fistula that exposes the ampullae of the lateral and superior canals, the nystagmus is rotary. A temporal bone CT will show
bony dehiscence of the horizontal semicircular canal or soft tissue abutting the canal (Figure 155-20 A, B).
Management is mastoidectomy with eradication of cholesteatoma;
there are several options regarding the management of the
fistula. Care should be taken when a fistula of the labyrinth is suspected because inadvertent removal of cholesteatoma matrix from an unidentified
fistula has disasterous results; the incidence of severe or total sensorineural hearing loss has been reported as 56% when the cholesteatoma matrix
was removed from extensive fistulas.
There are some general principles regarding the management of a labyrinthine fistula. When a cholesteatoma has been found, the sac should be
opened and the contents evacuated. The medial wall of the matrix should be palpated to detect any bony erosion. Once a fistula is identified, matrix
should be left over the site to protect the labyrinth (even if eventual removal is planned) while the remainder of the ear is cleared of disease. This
protects the labyrinth from irrigation solution and bony debris.
Once a fistula has been identified in a noninfected ear, the options are removal of cholesteatoma with immediate repair of the fistula or removal of
cholesteatoma leaving a small amount of matrix over the fistula and repairing this as a staged procedure 6 months later. Repair of the fistula at the
initial operation should be undertaken at the end of the procedure, after removal of cholesteatoma and completion of the mastoidectomy. Repair
should be staged in an infected ear.
When the fistula is exposed, it should be quickly covered with a tissue seal (fascia, vein, or perichondrium). Most authors advocate leaving the matrix
intact over extensive fistulas involving more than one canal, the vestibule, or the cochlea.121
Facial nerve paralysis
Facial paralysis secondary to otitis media has been reported to
account for 6% to 8% of peripheral facial paralysis, which is behind that of
idiopathic disease, trauma, tumors, and herpes zoster oticus.17,27 Facial paralysis may be a complication of acute or chronic otitis media. It occurs
more commonly in children with otitis media than in adults.27 In the young child, facial paralysis may be the first symptom of acute otitis media.3 The
pathogenesis can be suspected based on the timing of the paralysis with respect to the onset of the ear disease. When the paralysis occurs within 2
weeks of acute otitis media, it is most likely caused by edema of the nerve, which can become inflamed as a result of exposure of a dehiscent
segment to the active infection. In postmortem examination of 535 temporal bones, the facial nerve was found to be dehiscent in 55% (91% in the
tympanic segment, 9% in the mastoid segment). Of dehiscences in the tympanic segment, 83% were located adjacent to the oval window involving
the lateral, inferior, and medial portion of the canal, with the facial nerve protruding from its canal in 26%.7 Dietzel (cited by Kettel)56 reported that
57% of 211 temporal bones had a dehiscent segment of the facial nerve. The mechanism of paralysis is presumably acute neuritis with hyperemia
and cellular infiltration, leading to inflammatory edema of the nerve and compression within its bony canal. Subsequent ischemia leads to neurapraxia
of the nerve.3 Others have postulated that the route of inflammation may be the physiologic canaliculi between the middle ear and the fallopian canal
(such as those for the stapedial and chorda tympani nerves).
When facial paralysis occurs later than 2 weeks after the onset of otitis media, it should be assumed to be the result of erosion of the bony fallopian
canal with exposure of the nerve to the active infection (Figure 155-21). Progressive facial paralysis in the presence of stable conductive hearing
loss without a history of chronic otitis media suggests the presence of congenital cholesteatoma.104 Facial paralysis associated with chronic otitis
media is usually caused by neural compression from the mass effect of cholesteatoma. Labyrinthine fistula may co-exist in these cases.
Management of facial paralysis from acute otitis media is
myringotomy and antibiotics; more aggressive management is indicated
only if the infection fails to resolve or if electroneurography indicates neural degeneration.27 Complete recovery after resolution of the acute
infection is typical.
Mastoidectomy is indicated (1) if the paralysis occurs more than 2 weeks after the onset of otitis media, (2) if the patient has a history of chronic
otitis media, (3) if the paralysis fails to resolve after adequate management of the acute otitis media, or (4) if electroneurography indicates
degeneration of more than 90% of the motor nerve fibers within 6 days of onset of the paralysis.27 The goal of surgery in this setting is twofold:
eradication of disease and exploration of the fallopian canal for invasive granulation tissue. A complete canal wall-up mastoidectomy is performed.
The bone of the fallopian canal is thinned to allow observation of the nerve without uncovering it; unnecessary opening of the canal in the presence
of active infection should be avoided, if possible. In addition, it is best not to open the facial nerve sheath in the presence of acute infection.
However, if there is evidence of granulation tissue extending from a dehiscent segment into the bony canal, the canal should be opened proximally
and distally for the length of the extent of the granulation. Extraneural sheath granulations may be removed, but no granulations should be removed
from within the sheath; this tissue tends to infiltrate between fibers, and attempts to remove it may result in permanent injury to the nerve.
For patients with chronic otitis media and cholesteatoma, urgent surgery is indicated to remove the cholesteatoma mass, which will result in
decompression of the facial nerve at the site of involvement. No other facial nerve decompression is needed and the nerve sheath should not be