87 Mastoiditis

Infections of the middle ear and mastoid encompass a spectrum of potentially serious medical conditions and sequelae. Decreased hearing from ear infections may have a lifelong impact on speech, learning, and social and vocational development, causing these con­ditions to remain a major health concern.

Classification

Inflammatory diseases of the middle ear and mas­toid are categorized according to the underlying dis­ease process and location:

1. Acute suppurative otitis media (AOM) is char­acterized by obstruction of the eustachian tube, allowing the retention and suppuration of retained secretions. AOM is the medical term associated with, most commonly, the acute ear infection of childhood. Generally the course of this infection is self-limited, with or without medical treatment, and the retained infected secretions are discharged through either the eustachian tube or a ruptured tympanic membrane.

Acute coalescent mastoiditis can result from fail­ure of these processes to evacuate the abscess. Co­alescence of disease within the mastoid leads to pus under pressure and ultimately dissolution of sur­rounding bone. This condition may require urgent surgical evacuation because the infection is capable of spreading to local and regional structures.

3. Otitis media with effusion (OME) is an inflam­matory condition of the middle ear in which serous or mucoid fluid accumulates. Both AOM and OME are precursor conditions to tympanic membrane re­tractions and perforations. Ongoing eustachian tube dysfunction predisposes to persistent retained secre­tions in the ear and recurrent acute attacks of otitis media. A small percentage of these patients develop a chronic tympanic membrane perforation which, in most cases, allows eventual aeration of the middle ear and mastoid air-cell spaces and resolution of the underlying disease process.

4. Chronic suppurative otitis media (CSOM) is defined as an ear with a tympanic membrane perforation. Benign CSOM is characterized by a dry tympanic membrane perforation, unassociated with active infection. Active CSOM is the result of intermittent bacterial infection often in the pres­ence of ingrown skin in the middle ear and mastoid cavities. This skin ingrowth is known as cholestea­toma formation. Primary acquired cholesteatoma occurs through a tympanic membrane retraction into the attic of the middle-ear space, with a subsequent potential for extension into the middle ear and mastoid air-cell systems. Secondary ac­quired cholesteatoma is defined as skin growth through a tympanic membrane perforation into the ear.

Distribution and Incidence

Surveys of large pediatric populations demonstrate that 80 percent of all children will experience one or more episodes of AOM by the age of 6. Together AOM, 0ME, and CSOM comprise one of the most common disease entities affecting human popula­tions. Indeed, AOM is thought to be the most com­mon disease treated with antibiotics.

Prevalence studies have demonstrated an extraor­dinarily high incidence of complicated infections of the middle ear in African, American Indian, Alas­kan and Canadian Eskimo, Australian aboriginal, and New Zealand Maori pediatric populations, sug­gesting that disease-manifesting tissue destruction of the middle-ear and mastoid structures is much more prevalent in these areas. By contrast, studies of children in different geographic areas indicate that the incidence of uncomplicated disease in the middle ear is similar in all areas.

The incidence of complicated infections producing mastoiditis has dramatically declined since the ad­vent of antibiotics in the 1930s and 1940s. Prior to that time, acute coalescent mastoiditis complicated AOM in approximately 20 percent of the cases. Ini­tially, antibiotics cut into mortality rates from mas­toiditis, but overall moribidity remained unchanged.

Epidemiology

A variety of host and environmental factors, as well as infectious etiologic agents, have been linked to infection of the middle ear and mastoid. AOM occurs most commonly between 6 and 24 months of age. Subsequently, the incidence of AOM declines with age except for a limited reversal of the downward trend between 5 and 6 years of age, the time of entrance into school. The incidence of uncomplicated AOM is not significantly different in boys from that in girls. Mastoiditis, however, would appear to be more common among males.

Studies of eastern coast American children have demonstrated a higher incidence of middle ear infec­tions in Hispanic and Caucasian children than in black children. The higher incidence of middle ear and mastoid infections in certain peoples is not readily explained. Variability in eustachian tube size, orientation, and function among racial groups has been suggested as being responsible for differ­ences in disease incidence. Genetic predisposition to middle ear infection and associated complications has also been demonstrated. Down syndrome, cleft palate, and other craniofacial anomalies are also associated with a high risk of developing A0M, OME, and CSOM.

The severity of otitic infections is related to factors such as extremes of climate (temperature, humidity, and altitude) and poverty with attendant crowded living conditions, inadequate hygiene, and poor sani­tation. There is a well-recognized seasonal variance in the incidence of A0M. During the winter months, outpatient visits for AOM are approximately 4-fold higher than in the summer months. Although in­take of mother’s milk and avoidance of cigarette smoke appear to confer some protection against OME, no effect on the incidence of suppurative com­plications has been shown.

Etiology

Eustachian tube dysfunction is the most important factor in the pathogenesis of middle ear infections. The most commonly cited problem is an abnormal palatal-muscle, eustachian-tube vector, which com­monly occurs in young children. With adolescent growth, descent of the soft-palate-muscle sling rela­tive to the eustachian tube orifice improves the eu­stachian tube opening. However, poor tubal function may persist with mucosal disease (allergic, in­flammatory, immunologic impairment, or immotile cilia), extrinsic compression (enlarged adenoid or nasopharyngeal tumor), or palatal muscle dysfunc­tion (cleft palate and other craniofacial anomalies). Persistent eustachian-tube dysfunction induces a relative negative pressure in the middle-ear space. The lack of aeration and the accumulation of effu­sions provide an environment conducive to the devel­opment of OME or AOM.

Bacteriologic studies identify Streptococcus pneu­moniae and Hemophilus influenzae most frequently as the pathogenic organisms in A0M. Group A beta­hemolytic streptococcus, Staphylococcus aureus, and Branhamella Catarrhalis are less frequent causes of AOM. Gram-negative enteric bacilli are isolated on occasion in infants up to 6 weeks of age with A0M.

When AOM continues beyond 2 weeks as a result of inadequate antimicrobial therapy, progressive thickening of the mucosa lining the middle ear ob­structs free drainage of purulent secretions, thereby permitting bone destruction and extension of infec­tion. This process may eventuate in mastoiditis and possibly other local or intracranial extensions of sup­puration.

Immunology

The respiratory mucosal membrane that lines the middle-ear space and mastoid air cells is an immuno­logic defense consisting of constantly renewed mucus that contains lysozyme, a potent, bacteria-dissolving enzyme. In response to an invading organism, produc­tion of mucus is increased. Inflammatory dilation of vessels, white blood cell migration, and proteolytic enzyme and antibody deposition contribute to the formation of mucopurulent (containing both mucus and pus) secretions.

The incidence of otitis media and attendant compli­cations is higher in individuals with congenital or acquired immunologic deficiencies. The presence of a concomitant malignancy, the use of immunosup­pressive drugs, uncontrolled diabetes, and previous irradiation are also associated with a higher risk of developing AOM and related complications.

Clinical Manifestations

The onset of AOM in childhood is often associated with fever, lethargy, and irritability. Older children may experience earaches and decreased hearing. Ex­amination with a hand-held otoscope demonstrates tympanic membrane redness, opacity, bulging, and poor mobility when pneumatic pressure is applied. However, there is considerable variability in the symptoms and signs of acute otitis media.

OME is often characterized by hearing loss and a history of recurrent episodes of A0M. Otoscopic find­ings usually consist of fluid visible behind a re­tracted tympanic membrane.

CSOM in its active form often presents with foul­smelling drainage and longstanding hearing loss. Otoscopy reveals tympanic membrane retraction, perforation or hyalinization, and often, evidence of bony erosion, with the development of a cystlike mass called cholesteatoma. Development of pain in such an ear is a foreboding sign, as it often repre­sents the obstruction of drainage of the infection, and pus under pressure. Local complications of CSOM include bone erosion producing hearing loss, facial nerve dysfunction, sensorineural hearing loss, ringing sounds in the ear, and vestibular distur­bances. On occasion, infection will extend into the bony skull or into the soft tissues of the neck and scalp, either through normal preformed pathways such as vascular channels, or through progressive bone destruction.

Pathology

Pathological findings associated with AOM demon­strate inflammatory changes in the lining of the middle ear as well as suppurative exudates in the middle-ear cleft. The quantity of the exudate in­creases with time and exerts pressure on the tym­panic membrane. The bulging tympanic membrane may rupture spontaneously in the central or mar­ginal portions. Marginal perforations are more likely to lead to ingrowth of skin and the formation of a secondary acquired cholesteatoma. Primary ac­quired cholesteatomas arise in retraction pockets of the tympanic membrane that are induced by eusta­chian tube dysfunction. Cholesteatoma can also arise from congenital or traumatic implantation of skin into the middle ear as well as from abnormal changes in the middle-ear mucosal lining in re­sponse to inflammation.

Suppurative AOM persisting beyond 2 weeks can initiate the development of acute coalescent mas­toiditis. The progressive thickening of the mucosa of the middle ear begins to obstruct the drainage of mucopus through the eustachian tube. Stoppage of blood in the veins and the high acidity of that blood promote demineralization and the loss of bony parti­tions. As a consequence, separate air cells of the mas­toid coalesce into large cavities filled with mucopuru­lent secretions and thickened mucosal granulations. The erosion of bone, however, may not be confined to the air cell partitions within the mastoid bone. Other portions of the temporal bone including the posterior wall of the external canal, the mastoid cortex, and the thin, bony plates separating air cells from the sigmoid sinus and dura may likewise be eroded. Ex­tension of the infection beyond the mucosal lining of the middle ear and mastoid air cells may produce an intracranial complication, generally by passage of the infection along preformed bony pathways or through inflamed veins in intact bone.

History and Geography

Antiquity Through the Sixteenth Century

It is likely that humanity has always suffered from acute infections of the middle ear and attendant suppurative complications such as mastoiditis. Stud­ies of 2,600-year-old Egyptian mummies reveal per­forations of the tympanic membrane and destruction of the mastoid air-cell system. Evidence of suppura­tive destruction of the mastoid is also apparent in skeletal specimens from early Persian populations (1900 B.C. to 800 B.C.).

Hippocrates appreciated the potential seriousness of otitic complications and noted that “acute pain of the ear with continued high fever is to be dreaded for the patient may become delirious and die.” Early in the Roman era, the Roman physician Aulus Cornel­ius Celsus observed that “inflammation and pain to the ear lead sometimes to insanity and death.” The Arabian physician Avicenna related suppuration of the ear and mastoid with the brain, reasoning incor­rectly that the ear discharge was caused by the brain disease. For centuries, middle-ear and mastoid infec­tions producing discharges from the ear were consid­ered virtually normal conditions because they oc­curred so frequently.

Although the seriousness of ear suppuration was appreciated much earlier, the concept of opening the mastoid to relieve infection did not occur until the sixteenth century. The great medieval surgeon Ambroise Pare was called to the bed of Francis II of France. Pare found the young king febrile and deliri­ous with a discharging ear. He proposed to drain the pus through an opening in the lateral skull. The boy- king’s bride, Mary, Queen of Scots, consented. How­ever, the king’s mother, Catherine de Medici, refused to let the surgery take place, causing Mary to lose her first husband and throne while she was only 18 years old.

Seventeenth Through Eighteenth Century Notable advances in understanding the pathophysi­ology of aural suppuration were made in the late seventeenth century. Joseph DuVerney wrote Traite de VOrgane de VOuie (1683), which is generally re­garded to be the first monograph published on the subject of otology. It was the first book to contain an account of the structure, function, and diseases of the ear, whereas earlier works were devoted to purely normal otologic anatomy. In this work, DuVemey described infectious aural pathology and the mechanisms producing earache, otorrhea, and hearing loss. He was the first to describe extension of tympanic cavity infection posteriorly to the mas­toid air cells to produce the characteristic symptoms and findings of mastoiditis.

Noteworthy contributions were made by Antonio Valsalva (1704), who still believed that aural suppu­ration was secondary to cerebral abscess formation and was not the primary lesion. He did, however, suggest a method for removing purulence from the ear. This procedure consisted of blowing out strongly while holding the mouth and nose firmly closed, thus forcing air to pass into the middle ear by way of the eustachian tube. He suggested this maneuver as a means of expelling pus in cases of otitis. Valsalva’s student Giovanni Morgagni, in his great work On the Sites and Causes of Disease (1761), revealed post­mortem evidence that demonstrated that aural sup­puration was the primary source of lethal, intra­cranial abscesses.

In the early eighteenth century, Jean Petit of Paris performed what is generally believed to have been the first successful operation on the mastoid for the evacuation of pus. He demonstrated recovery “after the compact layer had been taken away with gouge and mallet.” He stressed the need for early drainage of mastoid abscesses because of the potential for “accidents which may supervene and render the dis­ease infinitely complicated and fatal.”

S. Stevenson and D. Guthrie, in their History of Otolaryngology (1949), describe how, in 1776, a Prus­sian military surgeon apparently treated a painful, swollen, draining mastoid by removing a portion of the overlying mastoid cortex. The surgeon was proba­bly unaware of Petit’s work, and the authors quote him saying, “Perhaps this is no new discovery, but for me it is quite new.”

Performance of the mastoidectomy operation suf­fered a setback when the procedure was performed on Baron von Berger, personal physician to the King of Denmark. The baron, hearing of the success of Petit and others, persuaded a surgeon to operate upon his mastoid to relieve tinnitus and hearing loss. The op­eration was performed before the importance of surgi­cal asepsis was realized, and resulted in a wound infection. The baron died of meningitis 12 days later, and the mastoidectomy operation fell into disrepute until the middle of the nineteenth century.

France was one of the first countries to remove otology from the sphere of the general surgeon and to give it a place of its own. One of the first to specialize in this discipline was Jean Marie Gaspard Itard. Itard was a military surgeon in Paris who carried out extensive study of otologic physiology and pathology, and published a textbook on these subjects, Traite des Maladies de VOrielle et de V Audi­tion, in 1821. He exposed many errors of his predeces­sors, particularly their opening of the mastoid cavity as a cure for deafness. Like Itard, Jean Antoine Saissy, a Parisian surgeon, was strongly opposed to puncturing the tympanic membrane for aural suppu­ration as recommended by his predecessors. Instead, he treated middle ear and mastoid suppuration by rinsing through a eustachian catheter. He described the technique in his Essai sur les maladies de Voreille interne (1829).

In 1853, Sir William Wilde of Dublin - father of the poet Oscar Wilde - published the medical classic Practical Observations on Aural Surgery and the Na­ture and Treatment of Diseases of the Ear. In this publication he recommended incision of the mastoid through the skin and periosteum for fluctuant mas­toiditis when symptoms and findings were life­threatening.

The nineteenth century saw the successful employ­ment of ether in a surgical operation by William Thomas Green Morton in 1846 and the introduction of chloroform by James Young Simpson in 1847. These, coupled with bacteriologic discoveries made by Louis Pasteur and the work of Joseph Lister on antisepsis, the invention of the electric light by Thomas Edison, and the work OfRudolph Virchow in cellular pathology, had profound effects upon the development of otologic surgery for suppuration.

James Hinton, a London surgeon, and Hermann Hugo Rudolf Schwartze of Halle are credited with establishing the specific indications and method of simple mastoidectomy. This operation involved re­moval of the bony cortex overlying the mastoid air cells. The insight and work of Schwartze led to the first systematic account of the operation as a scien­tific procedure to be performed when specific indica­tions were present and according to a definite plan. His rationale was so convincing that by the end of the nineteenth century, the operation had attained widespread acceptance and had overcome more than a century of prejudice against it.

In 1861 the German surgeon Anton von Troltsch had reported successful treatment of a case of appar­ent mastoiditis with a postauricular incision and wound exploration. He subsequently recognized that failure to address disease deeper within the middle ear recesses and mastoid invariably resulted in re­currence of otorrhea. In 1873 he proposed extensions of Schwartze^,s simple mastoidectomy to treat surgi­cally these problematic areas.

Following a similar line of reasoning, Emst von Kiister and Emst von Bergmann, in papers read before the German Surgical Society in 1889, recom­mended extending Schwartze’s mastoidectomy proce­dures to include removal of the posterior wall of the external canal and middle ear structures “to clear away all disease and so fully to expose the source of the suppuration that the pus is nowhere checked at its outflow.” This extended procedure became known as the radical mastoidectomy.

Prior to these remarkable advances in the surgical treatment of mastoiditis, the “mastoid operations” frequently failed because of delayed surgical inter­vention in cases in which infections had already extended beyond the mastoid process to involve in­tracranial stmctures. George Shambaugh, Jr., has noted that these patients died most likely despite, not because of, their mastoid operation (Shambaugh and Glasscock 1980). Many surgeons trained before 1870 were unable to absorb and practice Listerian doctrines, and this fact may have contributed to an overly conservative approach to surgical procedures. Properly indicated and performed, mastoidectomy for a well-localized coalescent infection proved to be extremely effective in removing the risk of serious complication from an abscess within the mastoid and in preventing continued aural suppuration. The addition of techniques for exteriorizing infectious processes in the less accessible apex of the temporal bone, as well as progress in making earlier diagnosis of mastoiditis, capped this important phase of oto­logic surgery for aural suppuration.

In many cases of chronic otorrhea treated with radical mastoidectomy, previous infection had de­stroyed the middle-ear sound-conducting system. Removal of the tympanic membrane and ossicular remnants was necessary in order to extirpate the infection completely. However, it soon became appar­ent that in a subset of cases of chronic otorrhea, the infectious process did not involve the inferior portions of the tympanic membrane or ossicular chain. In 1899, Otto Komer demonstrated that, in selected cases, the majority of the tympanic mem­brane and ossicular chain could be left intact during radical mastoidectomy, thus maintaining the preoperative hearing level.

In 1910 Gustav Bondy formally devised the modi­fied radical mastoidectomy for cases in which the inferior portion of the tympanic membrane (pars tensa) and the ossicular chain remained intact. He demonstrated that the removal of the superior bone overlying infected cholesteatoma adequately exte­riorized and exposed disease while preserving hear­ing. Despite the successful demonstration of this less radical approach in selected patients, otologic sur­geons were slow to accept Bondy’s procedure. Most likely, the preoccupation with preventing intracra­nial suppurative complications forestalled accep­tance of this less aggressive approach. Shambaugh and others in America and abroad recognized the utility of the Bondy procedure, and it finally gained widespread acceptance by the 1930s.

A marked decline in the need for mastoid opera­tions developed with the use of sulfanilamide and penicillin. The favorable results that were achieved with the use of these antibiotics in many cases en­couraged their application at earlier stages of severe infections including mastoiditis. At first, otologic surgeons were hesitant to abandon the established surgical drainage procedures for mastoiditis, fearing that antibiotics would mask the clinical picture and lead to late complications. It soon became evident, however, that if antibiotics could be given before localized collections of pus were established, fewer complications requiring surgical intervention would result. Nonetheless, modern-day physicians have rec­ognized that too low a dose of an antibiotic given for too brief a time, or the use of a less effective antibi­otic in the early stages of otitis media, may indeed mask a developing mastoiditis.

Interest in hearing-preservation in conjunction with sm^,gical treatment of chronic ear infections con­tinued to grow. The German surgeons F. Zollner and H. Wullstein share credit for performing the first successful repairs of the tympanic membrane using free skin grafting techniques in 1951. The ability to repair perforations of the tympanic membrane and seal the middle ear reduced the likelihood of persis­tent aural suppuration and associated mastoid and intracranial complications.

The emphasis on preservation and restoration of hearing in conjunction with the management of chronic ear infections has fostered the development of methods of ossicular reconstruction since the 1950s. Techniques in ossicular reconstruction are designed to simulate the middle-ear sound-conducting mecha­nism. Alloplastic prostheses made of polyethylene and Teflon and bioceramic materials have produced mixed results with respect to long-term hearing and prosthesis stability and acceptance.

The incus interposition technique of ossicular re­construction was introduced by William J. House in 1966. C. L. Pennington and R. E. Wehrs are credited with refinement of this technique for reestablishing ossicular continuity between the tympanic mem­brane and the cochlea.

In 1954 B. W. Armstrong reintroduced a proce­dure, first suggested by Adam Politzer in 1869, to reverse the effects of eustachian tube dysfunction. The procedure entails a limited incision of the tym­panic membrane and insertion of a tympanostomy tube. Theoretically, a functioning tympanostomy tube exerts a prophylactic effect by maintaining am­bient pressure within the middle ear and mastoid and providing aeration and drainage of retained middle-ear secretions. Tympanostomy tubes appear to be beneficial in restoring hearing and preventing middle-ear infections and structural deterioration while in place.

This review of the historical development of otology reports an evolution in the understanding and management of aural infections. Interestingly, current principles of the surgical treatment of chronic ear infections recapitulate this evolution. The essential principles and objectives upon which modern surgical procedures are based are (1) removal of irreversibly infected tissue and restoration of middle-ear and mastoid aeration; (2) preservation of normal anatomic contours, and avoidance of an open cavity, when possible, by maintaining the external ear canal wall; and (3) restoration of the middle-ear sound-transformer mechanism in order to produce usable postoperative hearing.

The historical lessons learned by otologists under­score the importance of adequate surgical exposure and removal of irreversibly infected tissue followed by regular, indefinite postoperative follow-up in or­der to maintain a safe, dry ear.

John L. Kemink, John K. Niparko, and StevenA. Telian

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