Otology Fellowship is now available
"Otology Fellowship Program" at Karnataka ENT Hospital & Research Center (R)
Thesis Research Paper of Dr. Prahlada N.B
Study of Clinico-pathological and Radiological Spectrum of Cholesteatoma in Children and Correlation of Computerized Findings with Surgical Findings.
THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS
FOR THE DEGREE OF M. S. (E. N. T.) OF THE POSTGRADUATE INSTITUTE OF MEDICAL EDUCATION AND RESEARCH, CHANDIGARH
JULY, 1995
PRAHALADA N.B.
CERTIFICATE
This is to certify that the work contained in this thesis entitled, "STUDY OF CLINICO PATHOLOGICAL AND RADIOLOGICAL SPECTRUM OF CHOLESTEATOMA IN CHILDREN AND CORRELATION OF COMPUTERIZED TOMOGRAPHIC FINDINGS WITH SURGICAL FINDINGS" has been carried out by Dr. Prahlada N.B. under our direct supervision and guidance.
All investigations in connection with this work have been carried out by the candidate himself and are genuine.
Dr. Suresh C. Sharma
Additional Professor
Additional Professor
Department of ENT,
Postgraduate Institute of Medical Education and Research,
Chandigarh .
Dr. Naresh K. Panda
Assistant Professor
Assistant Professor
Department of ENT,
Postgraduate Institute of Medical Education and Research,
Chandigarh
Dr. Rajiv Bapuraj
Assistant Professor
Assistant Professor
Department of Radiodiagnosis
Postgraduate Institute of Medical Education and Research,
Chandigarh
ACKNOWLEDGEMENTS
l wish to express my profound gratitude to my teacher Dr. Suresh C Sharma, Additional professor, Department of ENT, PGIMER, Chandigarh for the timely help and guidance given to me.
I wish to express my deep gratitude to Prof. S. B. S. Mann, Chief, Department of ENT, PGIMER, Chandigarh for his parental attitude and the unstinting support.
I am indeed grateful to Dr. Naresh K Panda, Assistant Professor, Department of ENT, for his support and valuable suggestions, not only in this study but otherwise as well.
I am thankful to Dr. Rajeev Bapuraj, Assistant professor, Dept of Radiology, whose every helping nature and advice was a source of inspiration at all stages of my work.
I thank all the little patients who have participated in this study, but for their cooperation this study would have been impossible.
I thank Mr. Sharma and Sunil Sharma for their expert assistance in the preparation of this work.
I thank all my Senior residents and fellow collegues for their cooperation and constructive criticism.
l would like to thank my parents for what / am today.
Dr PRAHLADA N B
Dedicated to my
Teachers, Parents and little Patients
INTRODUCTION
Otological experience has shown that the incidence of aural cholesteatoma in children is much lower compared to cholesteatoma in adults, the ratio of cholesteatoma in adults to children being 5.6:1(1) and 4:1 (2) . Aural cholesteatoma in children poses many challenges to the otologist by being a rapidly growing disease which is more extensive within a well pneumatized mastoid bowl (2, 3, 4).
Making the diagnosis of cholesteatoma in children is often a difficult task due to paucity of symptoms, the difficulty in examination, and their small, tortuous ear canals. The triad of otorrhoea, hearing loss and abnormal otoscopic findings should raise the possibility of cholesteatoma. The presence of congenital cholesteatoma presents another challenge in the diagnoses of pediatric cholesteatoma, which often presents as a white mass behind an intact eardrum.
The complications of chronic suppurative otitis media are commoner in the young individuals. In fact, younger the patient, the more likelihood of developing intracranial complications.
The subject of greatest debate among the otologist relates to the choice of surgical approach, which must provide; a disease free ear and serviceable hearing required for the development of child. the successful treatment of cholesteatoma in the paediatric age group has been achieved by using the same basic principles of therapy used for cholesteatoma in adults. The canal-wall-down approach is associated with a large mastoid cavity and a need for regular follow up and cavity care. The canal-wall-up approach which avoids a large mastoid cavity is associated with disadvantages of greater incidence of residual disease in the mesotympanum and recurrence of cholesteatoma in children. However, this problem can be overcome by a planned two stage canal-wall-up procedure, i.e. modified canal-wall-up procedures.
Inspite of such new surgical techniques, the recidivism of cholesteatoma is higher in children than compared to adults.
Radiologists have found that, the interpretation of the extent of cholesteatoma in children is difficult. 'Buckingham and Valvassori' have experienced discrepancies in 6 of the total of 1 1 cases in their pioneering study of tomography of temporal bone.
In the developed countries, the advent of powerful antibiotics, timely and precise surgical intervention by otologists has reduced the morbidity and mortality of cholesteatoma considerably. The same is not true for the developing countries like India, where vast areas of land are devoid of primary health services, let alone specialized otological facilities. Thus cholesteatoma is a major health problem with significant morbidity, particularly in paediatric age group.
Since a considerable number of children with acquired cholesteatoma attend the otolaryngology services of our hospital, it was felt necessary to study in detail the clinical spectrum of cholesteatoma in paediatric age group with regards to clinical presentation, radiological assessment and surgical findings and their respective follow-up in the post-operative period.
REVIEW OF LITERATURE
Paediatric cholesteatoma is of significant importance to the otolaryngologist as it poses many challenges. Firstly, the otologist must make a correct and an early diagnosis. Secondly, the otologist must provide a disease free ear that will remain safe throughout adulthood and can be easily followed up. Thirdly, a serviceable hearing level, which is important for the development of normal language and communication skills, should be achieved. Fourthly, the otologist should educate the patient and the family as to the nature of the disease, the need for long term follow-up, and the possibility of further radiographic studies, reconstructive surgery and aural rehabilitation.
As such the cholesteatoma itself is still a most intriguing pathological entity since the days of Johannes Mueller, who coined the term 'Cholesteatoma' in 1828, its remarkability in children further presents the otolaryngologist with a variety of diagnostic and therapeutic challenges.
Earlier studies on paediatric cholesteatoma have reported inconsistent results, which makes it difficult to fully understend the nature of this disease. Pioneering studies of Tos, Jahnke, Pavla et al and Glassock et alt, (4,7,8), propose that cholesteatoma is rapidly growing and more aggressive in children than in adults. Reudi (9) suggests that there is a connective tissue layer in the mastoid of young children that helps to promote cholesteatoma matrix growth. Similarly, the growth of the mastoid and the surrounding cranium may have some effect on the growth factor in cholesteatoma (10). Recently it has been proposed that cholesteatoma is less extensive disease with fewer complications, contrary to popular belief (11).
Majority of children have acquired cholesteatoma. Acquired cholesteatoma can be classified into two categories. The most common form is primary acquired cholesteatoma, which arises from a skin lined retraction pocket, within which retained keratin debris accumulates. This is also known as Attic retraction cholesteatoma (12), and is usually confined to the region of pars flaccida.
The pathogenesis of attic retraction cholesteatoma is the subject of much research and debate. There are four basic theories of development.
In invagination theory, Whittmack proposed that attic block caused by persistence of hyperplastic embryonic type of mucoperiosteum in the epitympanum result's in negative pressure in the attic. The negative pressure then causes retraction of Shrapnell's membrane into the attic, where keratin debris collects and cholesteatoma develops. Ruedi, Nager and Lange (9,13,14) in their basal cell hyperplasia theory state that, cone like extensions from the basal layer of epidermis can become invasive as a result of infection, Prickle cells grow into the subepithelial layer through breaks in the basal lamina, creating cones of epithelium or microcholesteatomas. Habermann (15, 5) proposed that following perforation of Shrapnell's membrane, epithelium grows into epitympanum, much like a secondary acquired cholesteatoma. This invasion ultimately reaches barriers that ca use the invading edges to meet and create a cyst or sac like structure. Keratin accumulation then causes progression of the disease. This theory is known as epithelial invasion theory and is supported by temporal bone studies of Palva et a1 (7) . Studies by Sade (16) tend to indicate that middle ear mucosa has the potential to transfornn into keratinizing squarnous epithelium Mucosal metaplasia may be triggered by infection, inflammation, and certain chemicals.
Irrespective of theories of pathogenesis, most common presenting symptoms of primary acquired cholesteatoma are: Hearing loss, Otorrhoea, Otalgia, tinnitus and vertigo. Most common finding at examination of ears are, a retraction pocket either in the ear-drum or extending toward the mastoid in 70% of children, followed by a tympanic membrane performation in one third and very few (8%) with a white mass behind the tympanic membrane i.e. congenital cholesteatoma.
In secondary acquired cholesteatoma, in growth of stratified squamous epithelium from the meatus to line the denuded tympanic cavity, epitympanum and antrum, following acute necrotic otitis media with sloughing of the tympanic mucoperiosteum results in cholesteatoma. This cholesteatoma offers a favourable culture medium for various pathogens and putrefactive bacteria from external auditory meatus, producing the characteristic foul smelling discharge. The microorganisms commonly found on culture are mixed, which include pseudomonas aeruginosa, proteus, enterobacter, Staphylococci, aerobic and anaerobic nonhaemolytic streptococci, diphtheroid bacilli and aspergillus molds.
The presence of congenital growth poses another challenge in the diagnosis of paediatric cholesteatoma, which presents with a mass behind the intact eardrum. Congenital cholesteatoma -tend to originate in the anterior epitympanum and over time, grow into the petrous apex without producing the symptoms until the patient in adult life develops hemifacial spasms (5, 17).
Previous theory of pathogenesis of congenital cholesteatoma postulated that failure or resorption of small masses of epidermal rests in the dorsolateral epitympanum of a human fetus could proliferative to form a cholesteatoma of the middle ear (18). This theory was not pursued and later the "Epidermoid formation theory" based on study of fetal temporal bones state that, squamous cell rests are identifiable from 10 to 33 weeks of gestation in the anterior superior lateral wall of the tympanic cavity, which resulted in cholesteatoma This epidermoid formation is present at histological differentiation point demarcating the transition from simple cubiodal epithelium lining the tympanic cavity and eustachian the anterior to it (19) . After 33 weeks of gestation the formation is not usually present.
Though radiological studies are a valuable aid in the diagnosis of ear diseases associated with changes in osseous structure, there is a conflict of opinions concerning the role of radiology in the management of cholesteatoma, a relatively common and potentially dangerous disease of the middle ear cleft. On the one hand, there is the opinion of Smyth (20): "In many otologic centres X-ray pictures of the petrous bones are made traditionally in every case of chronic otitis media. This practice constitutes an indispensable waste of money and time and does not in any way assist a competent surgeon. Has any surgeon who needs X-ray to show him whether there is cholesteatoma, and if so to indicate its dimensions, the right to sit behind an operating microscope. On the other hand, Dulac et al (21) contradict this statement by saying, "At present it is not possible to explore a chronic otitis with or without a cholesteatoma without employing tomography. These two extreme view points serve to illustrate the wide disagreement on this topic.
The history of radiology (22) of cholesteatoma dates back to 1905, when Schuller described the first view to visualize pathologic lesions in the area frequently involved in chronic ear disease, namely, "attic-aditus C antrum" or the "key area". This involves lateral skull view with an elevation of the beam to 30 degrees and gives a good exposure of the antrum and part of the attic. A portion of the head of the malleus may be seen, but the remainder of the ossicles are obscured by the dense bony labyrinth. The landmarks of temporal bone, the root of the zygoma, the condyle of the mandible, the temporomandibular joint, the external auditory canal superimposed on the tympanic cavity, the vestibule of the labyrinth and internal auditory canal, the cellular structure of the, mastoid process, the sinus plate and the tegmen plate are well visualized.
In 1920, Law (23) described the view which bears his name, in which the X-ray beam is directed caudally from a 15 degree elevation and anteriorly by 15 degrees. This is still a single most important radiologic projection in the management of cholesteatoma. The extent of pneumatization and the position of the sinus plate and dural plates are well visualized. However, ossicles are not visible since they are superimposed on the dense arcuate eminence of the superior vertical semicircular canal.
Many other variations which came into vogue later, are only used rarely in special circumstances to visualize the areas which are not visible in Law's view. Primary Mayer's view (24) is similar to Schuller's view, but X ray beam is still further elevated to depress the labyrinth and explore the cellular area in the antrum, aditus and attic. The head of the malleus and part of the incus are clearly seen in the Primary Mayer's view. In the conventional (usually referred to simply as the Mayer's projection), the same 40 degree elevation of the beam is maintained, but in addition, the head is rotated so that the face turns away from the centre by about 30 degrees. This rotation of the beam effectively frees the "key areas" from the dense shadow of the labyrinth. The malleus and incus are well seen in the upper tympanic and epitympanic cavities and the cellular pattern of the osseous outer attic wall is well indicated. But, the antrum is less well visualized because it is partially obscured by the arcuate eminence, and the obliquity of the Mayer's projection produces a distortion that may confuse the surgeon.
To lessen this distortion, the Owen's position (25) has been devised. The elevation of the beam is reduced to 30 degrees, but the rotation of about 30 degrees is maintained. All the anatomic landmarks of the Mayer's position, are retained but the malleus and incus are not visualized. The lateral wall of the attic with its pneumatic pattern is clearly visible and the antrum is in a more "normal" position, just above the arcuate eminence.
In patients who have been previously operated on the type of the operation can be identified in the Mayer and Owen positions. After simple mastoidectomy, the posterior canal wall and ossicles are intact. after modified radical operations, the ossicles are present but the posterior canal wall is absent. After radical surgery, both the ossicles and the posterior canal wall may be seen to have been removed.
Stenver's view (26) is taken with central ray depressed, with a rotation of the face toward the centre so as to bring the petrosa perpendicular to beam. This projection is best for the antrum, cellular structure of the petrous apex, internal auditory canal and vestibule of the labyrinth. The position also shows the tegmen plate, tympanic cavity, ossicles, condyle of the mandible and mastoid air cells lateral to the antrum and in the mastoid tip.
The third projection of Chausse (Chausse III) (22) is a modified frontal projection useful for the study of the attic, aditus and mastoid antrum and especially of the lateral wall of the attic. This wall run from back to front and slightly outward, forming an angle of 10 and 15 degrees with sagittal plane of the skull.
The Chamberlain-Towne's view (22) and Submentovertex views are used to view the petrous apex and mastoid antrum but have no advantage over the Stenver's position, with the disadvantage of loss of clarity and detail because of increased antrum-to-film distance. Therefore, these positions are not used routinely.
In the typical case of chronic otitis with cholesteatoma the infection develops in a poorly pneumatized temporal bone and the disease process is limited to the tympanic cavity, epitympanic cavity, aditus and antrum. The bone of the mastoid process is usually sclerotic and the few cell wall very thick. The first evidence of bone destruction is the loss of the normal osseous pattern of the attic. As the disease progresses, the aditus is widened and finally antral enlargement can be demonstrated. In the opinion of most radiologists an enlargement of the mastoid antrum is the most important and indispensable feature in the radiological diagnosis of cholesteatoma of the middle ear. According to McMillan (27), the normal sized antrum is 6 mm wide by 10 mm high in a sclerosed mastoid. Any increase in size of the antrum has been considered to be due to erosion of the bone by growing cholesteatoma. However, very small, as well as large antra may occur as normal variants. These findings may also be caused by granulation tissue as well as cholesteatosis. A condensation of the periantral bone is considered as additional evidence. Cholesteatoma itself casts no shadow and its presence can only be inferred from the bone erosion it produces. Consequently cholesteatoma which do not produce bone erosion cannot be diagnosed by conventional radiology. Winderen and Zimmer (28) classified cholesteatoma radiologically depending on their size into three groups: Large ("bean-sized" and larger), small ("pea-sized" and smaller) and medium (the size between these two extremes).
Large cholesteatoma may cause erosion of the dural plate or sinus plates with or without sequestration, which can be visualized in Law's or Shullers views. Erosion of semicircular canal sufficient to produce a labyrinthine fistula may sometimes be demonstrated in the Stenver's view and Chausse III projection (22).
It is difficult to diagnose recurrent cholesteatoma on plain X-rays in patients who have keen previously operated on unless serial films are available showing progressive enlargement of the cavity.
Congenital cholesteatoma of the middle ear produces a sharply demarcated area of bone destruction with a sclerotic margin but without evidence of chronic ear disease. Valvossori (6) considers that there are two criteria which distinguish a cholesteatoma of the middle ear cleft which has congenital rather than acquired origin. these are:
a) An intact ear drum with no evidence of a perforation.
b) An intact spur with erosion of the attic walls higher up and not involving the site of attachment of the eardrum, giving a scooped out appearance of outer attic wall.
b) An intact spur with erosion of the attic walls higher up and not involving the site of attachment of the eardrum, giving a scooped out appearance of outer attic wall.
Inspite of these observations, the diagnosis of cholesteatoma by conventional radiography has evaded eyes of many observers. In Waltner's (29) series attic cholesteatoma remained undetected in X-ray film studies and the diagnosis of antral cholesteatoma was extremely inaccurate. McMillan (27) found bone destruction of the temporal bones in 45% of 288 cases of surgically confirmed cholesteatoma with Law's projection and in 60% of cases when using Towne's projection, whereas Holmes (1938) and Chat and Kittredge (1958) noted destruction in 50% of cases were same projections were employed. Bert Jensen et al used Schuller, Runstrom III and Chausse III projections in 85 cases and found destruction in about 62% of cases. By combining a number of standard projections Winderen and Zimmer (28) made a definitive diagnosis of cholesteatoma in only 25% of their cases and found indications of cholesteatoma in another 50%(14).
The chances of detecting cholesteatoma by conventional radiography is still smaller in children. The mastoid in children with acquired cholesteatoma were reported as pneumatized in 54%, one half of these having clouding of the air cells. In 46% the mastoid was observed to be sclerotic. Majority of patients with congenital cholesteatoma have normal mastoid pneumatization, only a few cases have poor pneumatizartion and clouding due to associated effusion as an exception (30).
Conventional X-ray tomography was a further development in radiological diagnosis of diseases of the inner and middle ear. The IL tomography is a method of examining body organs and structures by serial sections obtained in various planes. With conventional X-ray tomography, sections of various thickness are obtained by blurring out objects above and below the desired plane. In such a system, during the exposure, film and Xray focus move in opposite directions with a constant ratio between their velocities and the film describing a translatory motion in relation to the object (22, 30).
The linear tomography employs simplest type of movement, which also has the shortest exposure time. The linear is most suitable for the larynx, but less suitable for petromastoid (30).
Complex motion of the X-ray tube, either hypocycloidal or spiral, gives the most uniform blurring of structures outside the plane of the section, as well as producing thinner sections of 1-2 mm thickness. The polytome continues to be used for routine demonstration of the petrous temporal none, as this gives the best and most convenient demonstration of bone detail, especially of internal auditory meatus, more cheaply and with less radiation to the patients eyes than either plain films or computerized tomography (30) .
Usually anteroposterior tomographic views are taken for the diagnosis of cholesteatoma and it affords sufficient information about the lesions in the attic and antrum. It is only in the event of special complications, in particular facial palsy, that lateral views are obtained in order to visualize better the canal of the facial nerve (31).
The anteroposterior projection shows the characteristic structures in the anterior part of the tympanic cavity. In normal radiography, the superomedial lip osseous part of the external auditory canal is termed the "Radiological spur". Projecting upwards from this spur there is the lateral wall of attic, another very important landmark. In addition, Medially, the promontary with cochlea can be seen and just above this the second part of the canal for the facial nerve (31). The tegmen tympani is often entirely absent or only faintly visible on normal tomograms. Thus its absence is not necessarily a sign of pathological destruction. Antrum and the semicircular canals can be demonstrated in slightly posterior cuts.
The tomographic diagnosis and evaluation of the extent of cholesteatoma is based on the detection of bony erosion and soft tissue changes in the middle ear and mastoid. Of the two findings only the first is reliable, since the radiographic density of a cholesteatoma is same as that of granulation tissue and other soft tissue masses 3l . With the help of tomography surgeon can detect before surgery extensive erosion of the lateral attic wall, absence of the lateral attic wall, erosion of the posterior external auditory canal, the status of the ossicles, labyrinthine involvement, facial canal erosion, extension into the petrous apex, exposure of the sigmoid sinus and tegmen, and unexpected anatomic variations and anomalies of the temporal bone, such as an anomalous deviation in the course of the facial nerve, a high jugular bulb into the hypotympanum and an aberrant internal carotid artery (32).
The tomographic criteria for the diagnosis of cholesteatoma is based on a study by Buckingham a& Valvossori (6) , who correlated otoscopic findings with tomographic findings and made following observations :
The characteristic radiographic pattern for pars flaccida cholesteatoma consisted of the following :
a. There was erosion of the anterior portion of the lateral wall of the attic in 27 of the 30 cases.
b. Erosion of anterior tympanic spine in 22 of the 30 cases.
c. Though medial displacement of the head of malleus with or without erosion seen only in 10 of the 30 cases, this finding was pathognomonic for cholesteatoma of the pars flaccida.
Tomographic findings in pars tensa cholesteatoma particularly involving posterosuperior marginal perforation were
a. The posterior portion of the lateral wall of the attic was eroded in 15 of 27 cases.
b. Erosion of long process of the incus in 22 of the 27 cases.
c. In 8 of 27 cases, the head of the malleus and body of the incus were displace laterally, and this was pathognomonic of pars tensa cholesteatoma.
The radiographic pattern of the findings in combined perforations was combination of the patterns described for the perforations of the pars tensa and pars flaccida.
Later they correlated these findings with surgical findings of cholesteatoma and found that the tomographs accurately predicted the extent of the surgical lesion in most of the cases. 80 of the 100 cases of cholesteatoma correlated well. In the remaining 11 cases, the extent of the cholesteatoma into the antrum and mastoid could not be accurately predicted. Five of these failures were in large pneumatic mastoids in which the cholesteatoma had infiltrated into the pneumatic cells but had not yet begun to destroy the cell system. The tomographs, however, did show clouding of the mastoid cells without cell wall destruction.
Brunner and Sandberg (31), in their series of 90 cases of cholesteatoma found that, distended antral cavity in 71 % of cases, smooth walled cavity in 58% of cases, destruction of the lateral attic wall in 51 % of the cases, absence of tip of the spur in 46% of the cases, destruction of the tip of the spur in 16% of the cases, destructive changes in the medial wall of the tympanic cavity in 21 % and absence of entire ossicles in 37%. A Berret et a1 (33), in their series of 25 children, found destruction of the radiological spur in only 60% of the cases and were able to diagnose cholesteatoma in only 80% of the cases using both conventional radiography and tomography.
Though standard linear or pluridirectional tomography was aimed at improving visualisation of localized areas of the body. A radiological image derived from these methods had at least two limitations from point of view of diagnostic specificity (30). They are:
a) Presence of background blur or structures above and below the focal plane.
b) A relatively large proportion of the detected radiation scattered from the patient.
Even if these two limitations could be reduced to "acceptable" levels, conventional films and screens are inherently nonuniform and relatively less sensitive than computerized tomography, and would limit subject contrast 3% to 5% which is greater than the range for some tissue.
Therefore, the advent of computerized tomography heralded a new dimension in the diagnosis of the middle and inner diseases which mitigate the observational limitation of conventional x-ray tomography.
High resolution CT was a further step in this direction which opened a new vista to various explorers to study and demonstrate the detail anatomy of temporal bone. various structures that were previously poorly visible on conventional radiography and pluridirectional tomography are made clearly visible by HRCT. However, complex structural relationships within the temporal bone cannot be visualized on single plane, making understanding of the CT anatomy of the temporal bone challenging and difficult. Though many planes are possible and have been tried, only two planes, axial and coronal planes are used for the temporal bone. The axial plane, also called transverse or horizontal plane can be obtained in CT with the patient in a comfortable position and the gantry is tilted slightly to adjust the scan parallel to the nasion-binaural plane or orbitomeatal plane. The examination area extends to between the first turn of the cochlea and the superior semicircular canal. Axial plane is an ideal tomographic plane for the baseline study of the temporal bone and provides patient comfort, the possibility of comparing both ears and the only disadvantage is the radiation dose received by lens of the eyes. The coronal plane is obtained with patient in the prone position and the head tilted upwards. The gantry is tilted until the scan plane is perpendicular to thee nasion binaural or orbitomeatal plane or parallel to ramus of the mandible. The examination area extends to between the anterior margin of the attic and the posterior semicircular canal (32, 34).
Many authors have studied HRCT anatomy of the temporal bone of the live patients, cadavers and dry skulls with intact ossicles and have correlated this with microdissections of temporal bones (35, 36).
The computerized tomographic evaluation of the acquired cholesteatoma is based on the detection of a non-dependent, homogenous soft tissue mass with a focal area of bone destruction. Of the two findings the second one is reliable since radiographic density of a cholesteatoma is the same as that of granulation tissue and other soft tissue masses (6). However, in HRCT, the granulation tissue has higher computed tomography attenuation values than cholesteatoma and often can be differentiated from the cholesteatoma. Complete opacification of the middle ear with no bony destruction makes radiologic differentiation of cholesteatoma from middle ear effusions and granulations tissue is often difficult. The presence of the an air fluid level or a soft tissue (fluid) mass in the dependent portion of the middle ear would render support for a diagnosis of effusion. On occasion, aggressive infections such as active chronic suppurative otitis media or soft tissue tumours may mimic cholesteatomas by causing erosion of bone or ossicular displacement.
In the attic following signs indicate the cholesteatoma (38):
a) Destruction of the scutum i.e., lateral spur of the bone formed by the junction of the lateral boundary of the attic and the roof of the external auditory canal. And this is the earliest sign.
b) Bone destruction in the lateral attic wall.
c) Destruction of the ossicles.
d) Erosion of the medial attic wall.
This is a less common sign but may lead to involvement of the facial canal or a labyrinthine fistula.
Complete or partial destruction of the malleus and incus and sometimes displacement medially or laterally by the cholesteatoma may be demonstrated, but the most unusual findings is a slight downward displacement of the malleus. Demonstration of this displacement and of the cholesteatoma as a clearly defined mass are possible with HRCT.
Cholesteatoma in the antrum is characterized by cavity formation. These cavities are smooth walled. A cavity with irregular boundaries is usually due to chronic otitis with osteitis. It is important to differentiate a cavity due to a cholesteatoma from normal mastoid antrum.
Mahammood P. Mafee et a1 (39) correlated CT findings with that of pluridirectional tomography and concluded by saying, "though tomography is superior in demonstrating subtle bony changes, the superior contrast resolution of CT makes it the method of choice in the demonstration of the soft tissue masses". Chat Virapongse 40 et al did similar correlation, but they continued to advocate tomography and recommended both CT and pluridirectional tomography in conjunction to study middle ear soft tissue masses. Pluridirectional tomography for its accurate diagnosis of osseous abnormalities and CT for soft tissue masses.
Inspite of the advent of high resolution computerized tomography, the tomographic interpretation of the extent of cholesteatoma in children is difficult. Buckingham and Valvassori 6 have found six of the total of 11 cases of discrepancies in tomographic prediction of the extent of the lesion in children.
Reports of one series (41) state that cholesteatoma involved the ossicles less frequently in children, whereas others (7) reported that the ossicles were most vulnerable in the paediatric acquired cholesteatoma erosion of the incur occurred most frequent (78%) followed by involvement of the malleus (54%) and the stapes (40%) (10). These authors also state that, in comparison to adult cholesteatomas, complications occurred less often in the paediatric group. Whereas, others have experienced more complications in younger individuals. And few have followed an adage, "Younger the patient, the more likely is he/she to develop an intracranial complication" (42).
The subject of greatest debate among otologists relates to choice of surgical approach. Sheehy, Jansen and Glasscock (1, 3, 43) have advocated Canal-wall-up mastoidectomy, whereas Canal-wall-down mastoidectomy has gained acceptance by Jahnke and Palve (4, 7). Others espouse a flexible attitude, selecting the surgical procedure after taking into account several factors: The location and extent of the disease, the clinical assessment of eustachian tube function, the mastoid size and pneumatization and the degree of involvement of the ossicles.
The functional status of the eustachian tube was estimated indirectly by the appearance of the middle ear space, the condition of the pars tensa, the pneumatization of the mastoid bone, impedance audiometry and presence of either nasal obstruction or adenoid hypertrophy.
Canal-wall-down mastoidectomy tended to be performed in the children with the most extensive disease, poor eustachian tube function and sclerotic mastoids. Canal-wall-up procedures were used in children who generally had localised disease and clinically had adequate eustachian tube function and few with minimal disease in mesotympanum required only tympanotomy. In contrast, the children with congenital cholesteatoma who were generally younger tended to have disease localized to the middle ear and frequently could be treated with an extended tympanotomy.
Primary reconstruction of the ossicular mechanism has been endorsed by most of the authors as a basic principle. Occasionally, reconstruction was done in states with extensive disease, poor eustachian tube function, and no middle ear space.
A higher rate of recidivism was experienced by authors who favoured a single surgical approach. Sheehy and Glasscock (1, 33) reported 25% and 5% of recidivism with single approach i.e., canal-wall-up approach. The results are same with those who used only canal-wall-down technique. Low failure rate was experienced by those who adopted a philosophy of treating each cholesteatoma individually and selecting the most appropriate procedure that will assure the eradication of the disease completely, as dictated by the operative findings. Most authors unanimously opine that children with acquired cholestesatoma treated on the average have worse hearing than in the overall pediatric series, probably because of the influence of better hearing levels observed in the congenital subgroup. In general, the children who had good hearing preoperatively tended to mintain their hearing after surgery, while those who had poor hearing preoperatively had only slight improvements.
The above studies demonstrate that the nature of pediatric cholesteatoma is still incompletely understood. And further studies needs to be done to understand the nature, early means of detecting children who are at risk of forming cholesteatoma so that the methods can be devised to try to prevent this disease. Though the surgical treatment of cholesteatoma in the pediatric age group can be achieved by using the same basic principles of therapy used for cholesteatoma in adults, it is anticipated that improved surgical techniques will evolve so that recidivism will be decreased, hearing results improved and postoperative care minimized.
OBSERVATIONS
A total of 25 patients, below the age of 14 years with chronic suppurative otitis media and cholesteatoma requiring mastoid exploration were treated in ENT Department of PGIMER, Chandigarh within the period of 18 Months (from January 1994 to June 1995). The detailed information regarding age, sex, clinical findings, radiological findings, intraoperative findings and outcome of the patients is given in master charts.
Table I: Sex Distribution (n=25)
| Sex | No of Patients | Percentage (%) |
| Male | 14 | 56% |
| Female | 11 | 44% |
| Total | 25 | 100% |
Observations
Of the 25 patients, 14 (56%) were boys and 11 (44%) were girls.
Chart. 1: Distribution by Sex (n=25).
Table II: Age Distribution (n=25)
| Age Group | No. of Cases | Total | Percentage | |
| Male | Female | |||
| Group I: 0 - 2 years | 0 | 0 | 0 | 0% |
| Group II: 2.1 - 5 years | 2 | 1 | 3 | 12% |
| Group III: 5.1-8 years | 1 | 0 | 1 | 4% |
| Group IV: 8.1 - 11 years | 6 | 2 | 8 | 32% |
| Group V: 11.1 - 14 years | 5 | 8 | 13 | 52% |
Observations
All patients were divided into 5 age groups. Group 1: 0-2 years of age, group II : 2.1-5 years of age, group III : 5.1-8 years of age, a group IV 8.1-11 years of age and group V : 11.1-14 years of age. There were no patients .in group I : 0-2 years of age and the youngest patient was 5 years of age. Male predominance was seen in patients aged upto 11 years (Fig. 2). Girls marginally out-numbered boys in the age group 11. 1-14 years (Fig. 2).
Fig. 3: Distribution by Age.
Table III: Distribution by involved ears (n= 25)
| Ear involved | No. of Cases | Percentage (%) |
| Right | 7 | 28% |
| Left | 13 | 52% |
| Both | 5 | 20% |
Observations
Of the 25 cases, 7 (28%) patients had disease only in right ear, 13 (52%) patients had disease only in left ear and the remaining 5 (20%) patients had disease in both ears.
5 patients with bilateral ear disease, the ear with active, serious and extensive disease was operated on first (Fig. 3).
Fig. 3: Distribution by involved ears.
Table IV: Symptoms Distribution (n=25)
|
Symptoms
|
No. of Patients
|
Percentage (%)
|
| Otorrhoea | 25 | 100% |
| Hearing loss | 22 | 88% |
| Earache | 4 | 16% |
| Vertigo | 1 | 4% |
| Tinnitus | 3 | 12% |
| Postaural abscess | 4 | 16% |
Observations
Commonest presenting complaint was otorrhoea (100%) followed by hearing loss (88%) and tinnitus (12%). 4 (16%) patients presented with post-aural abscess and only one patient with vertigo. Patients with post aural abscess also complained of earache.
Table V: Distribution by duration of complaints (n=25)
|
Duration in years
|
No. of Patients
|
Percentage (%)
|
| 0 - 3 years | 8 | 32% |
| 3.1 - 6 years | 7 | 28% |
| 6.1 - 9 years | 3 | 12% |
| 9.1 - 12 years | 4 | 16% |
| > 12 years | 3 | 12% |
Observations
15 patients had duration of complaints of less than 6 years. 8 of these patients were symptomatic for 3 years or less. four patients had complaints since their first year of life. Average duration of complaints was 6.9 years (Fig. 4).
Fig. 4: Distribution by duration of Complaints.
Table VI: Distribution by Ear findings (n=25)
|
Ear findings
|
No. of Patients
|
Percentage (%)
|
| PERFORATION/RETRACTION | ||
| Total | 0 | 0% |
| Subtotal | 2 | 8% |
| Central | 6 | 24% |
| Posterosuperior | 12 | 48% |
| Anterosuperior | 3 | 12% |
| Attic | 6 | 24% |
| SITE OF CHOLESTEATOMA | ||
| Posterosuperior | 12 | 48% |
| Attic | 6 | 24% |
| Others/Anterosuperior | 3 | 12% |
| OTHERS | ||
| Granulations | 1 | 4% |
| Polyp | 1 | 4% |
| Posterior canal wall sagging | 2 | 8% |
| Cavity | 1 | 4% |
| Mass behind an intact drum | 0 | 0% |
Observations
On microscopic examination of the diseased ear, presence of retraction pocket was the commonest finding. 48% had retraction in the posterosuperior region, 24% of the cases had attic retraction and remaining 12% of the cases had anterosuperior retraction pocket. 8 (32%) patients had associated tympanic membrane perforation. 2 of these 8 patients had subtotal perforation and remaining small central perforations. The commonest site of cholesteatoma was posterosuperior region.2 patients, had posterior canal wall sagging and therefore tympanic membrane could not be visualized. Granulations, polyp and recurrent cholesteatoma in operated cavity were encountered in one patient each. There were no patients with cholesteatoma behind an intact drum.
Table VIIa: Distribution by Pre-operative hearing loss
|
Type of Hearing loss
|
No. of Patients
|
Percentage (%)
|
| Conductive | 24 | 96% |
| Sensorineural | 0 | 0% |
| Mixed | 1 | 4% |
Table VIIb: Level of Hearing loss
|
A-B Gap
|
No. of Cases
|
Percentage (%)
|
| 0 - 10 dB | 5 | 20% |
| 11 - 20 dB | 2 | 8% |
| 21 - 30 dB | 6 | 24% |
| 31 - 40 dB | 11 | 44% |
| > 41 | 1 | 4% |
Observations
All patients had pure conductive loss, except one patient who had a mixed loss with 30 dB air-bone gap (Table 7a). Only one fifth of the patients (20%) had minimal hearing loss and almost half of the patients (44%) had moderate conductive loss with 31-40 dB air-bone gap. Only one patient had severe conductive loss with 44 dB AB gap (Fig. )
Table VIII: X- ray Law's lateral oblique view
|
Findings
|
No. of Cases
|
Percentage (%)
|
| Pneumatized | 0 | 0% |
| Sclerotic | 15 | 60% |
| Lytic lesion | 9 | 36% |
| Cavity | 1 | 4% |
Radiological findings
Majority (60%) X-rays of involved ear showed sclerotic mastoid. 36% of the cases showed a lytic lesion and one X-ray showed an operated cavity mimicking a lytic lesion.
Computerized Tomographic findings
Table IX: Evidence of Cholesteatoma
|
Evidence of Cholesteatoma
|
No. of Cases
|
Percetnage(%)
|
| Soft tissue density mass alone | 3 | 12% |
| Soft tissue density mass + Bony erosion | 20 | 80% |
| Total | 23 | 92% |
Preoperative computed tomography diagnosis of cholesteatoma was made in 23(92%) cases. The hall mark of cholesteatoma was non-dependent soft tissue mass alone and/or bony erosion or smooth bony expension was present in all these cases. The distribution of these findings in the various designated regions of the middle ear cavity is given in the table below.
Computerized Tomographic findings
Table X: Extent of the Disease
| Extent | Soft tissue density mass | Soft tissue density mass + bony erosion | Total | Percentage (%) |
| Protympanum | 5 | 4 | 9 | 36% |
| Mesotympanum | 10 | 1 | 11 | 44% |
| Posterior-tympanum | 10 | 3 | 13 | 52% |
| Epitympanum | 4 | 18 | 22 | 88% |
| Hypotympanum | 9 | 2 | 11 | 44% |
| Antrum | 9 | 13 | 22 | 88% |
| Aditus | 0 | 21 | 21 | 84% |
| Mastoid Air cells | 1 | 18 | 19 | 76% |
| Perilabynthine cells | 0 | 6 | 6 | 24% |
On HRCT, epitympanum and antrum were the commonest sites of cholesteatoma, 88% each. Aditus was involved in 21 (84%) cases and posterior tympanum in 13 (52%) cases. 11 (44%) of the cases had involvment of mesotympanum and hypotympanum and 9 (36%) cases had involvment of protympanum. Peril abyrinthine cells were involved in 6 (24%) cases.
Computerized Tomographic findings
Table XI: Involvement of Ossicles
|
Ossicle
|
No. of Patients
|
Percentage (%)
|
| Malleus: Handle | 13 | 52% |
| Head | 11 | 44% |
| Incus | 15 | 60% |
| Stapes |
Inconsistent visualization
|
|
Destruction of handle of malleus could be identified in 13 (52%) cases and involvement of head of malleus was seen in 11 (44%) cases. Incus was eroded in 15 (60%) cases. However, visualization of stapes was inconsistent with both axial and coronal planes.
Computerized Tomographic findings
Table XII: Complication of cholesteatoma
|
CT Findings
|
No. of Cases
|
Percentage (%)
|
| Ossicular destruction | 15 | 60% |
| Facial Canal Dehiscnece | 4 | 16% |
| Lateral semincircular canal erosion | 2 | 8% |
| Mastoid Cortex dehiscence | 3 | 12% |
| Sinus plate dehiscence | 1 | 4% |
| Dural plate dehiscence | 0 | 0& |
Preoperative HRCT diagnosed dehiscence of horizontal segment of facial canal in 4 (16%) cases. 2 (8%) cases had erosion of lateral semicircular canal and mastoid cortex dehiscence was seen in 3 (12%) cases. No patient had dural plate dehiscence and only one patient (4%) had sinus plate dehiscence.
Table XIII: Distribution by microorganisms in ear discharge (n = 25)
|
Organisms
|
No. of Patients
|
Percentage (%)
|
| Streptococci | 4 | 16% |
| Staphylococci | 6 | 24% |
| H. Influenza | 2 | 8% |
| P. Aueruginosa | 4 | 16% |
| Acinobacter | 4 | 16% |
| Mixed Flora | 2 | 8% |
| Sterile pus | 3 | 12% |
Commonest organisms isolated from ear discharge were Staphylococcus aureus (24%) followed by B haemolytic Streptococci (16%), P. aeruginosa (16%) and Acinobacter (16%). 8% of the cases grew H. influenzae. It was noticed that 8% of the cases had mixed flora and 12% of the cases did not grow any organism (Fig. 6).
Table XIV: Distribution of Surgical findings
|
Pathology
|
No. of Patients
|
Percentage (%)
|
| Cholesteatome | 17 | 68% |
| Cholesteatoma + Granulations | 3 | 12% |
| Polyp + Cholesteatoma | 1 | 4% |
| Granulations | 3 | 12% |
| Mucosal hypertrophy | 1 | 4% |
On surgical exploration, commonest pathology was cholesteatoma. 3 (12%) cases had only granulations. 3 (12%) cases had both cholesteatoma and granulations. One (4%) patient had polyp and one patient (4%) mucosal hypertrophy only (Fig. 7).
Surgical Findings
Table XV: Extent of Ear disease
|
Extent
|
No. of Cases
|
Percentage (%)
|
| Attic | 2 | 8% |
| Attic + Aditus + Antrum | 11 | 44% |
| Attic + Aditus + Antrum + Mesotympanum | 10 | 40% |
| Antrum | 1 | 4% |
| Others: Mucosal hypertrophy in attic | 1 | 4% |
Observations
84% of the patients had extensive disease with 44% of these patients had disease involving antrum, aditus and attic and remaining 40% had involvement of mesotympanum in addition to these. 4% of the patients had involvement of attic only. Cholesteatoma was found in attic and aditus in 8% of cases and only in antrum in 4% of the cases. One patient had only mucosal hypertrophy in attic (Fig. 8).
Surgical findings
Table XI: Ossicular involvement
|
Ossicle
|
No. of Patients
|
Percentage (%)
|
| Malleus: Handle | 15 | 60% |
| Head | 16 | 64% |
| Incus | 17 | 68% |
| Stapes | 06 | 24% |
On surgery it was noticed that incus (68%) was frequently involved followed by head of the malleus (64%). Handle of malleus was necrosed in 15 (60%) cases. Only 6 (24%) had necroses of stapes suprastructure.
Table XVII: Histopathology
|
Histopathology
|
No. of Patients
|
Percentage (%)
|
| Cholesteatoma | 21 | 84% |
| Granulations | 3 | 12% |
| Polyp | 1 | 4% |
Histopathology diagnosed cholesteatoma in 21 (84%) cases and granulations in 3 (12%) cases. One case had an inflammatory polyp.
Table XVIII: Correlation of CT scan and operative findings
|
Correlation
|
CT
|
Surgery
|
Cases in Agreement
|
False +VE
|
False -VE
|
Sensitivity
|
Specificity
|
| Evidence of Cholesteatoma | 23 | 21 | 21 | 2 | 1 | 95 | 75 |
The HRCT found to be very sensitive (95%) in diagnosing cholesteatoma accurately, however HRCT could not differentiate cholesteatoma from granulations and therefore less specific (75%)
Table XIX: Extent of the disease
| Extent | CT Scan | Surgery | Cases in Agreement | False +VE | False -VE | Sensitivity | Specificity |
| Protympanum | 9 | 6 | 6 | 3 | 0 | 100 | 84 |
| Mesotympanum | 11 | 8 | 7 | 4 | 1 | 87 | 76 |
| Post-tympanum | 3 | 9 | 9 | 4 | 0 | 100 | 75 |
| Epitympanum | 22 | 23 | 23 | 0 | 1 | 95 | 100 |
| Hypotympanum | 11 | 5 | 5 | 6 | 0 | 100 | 70 |
| Antrum | 22 | 22 | 21 | 1 | 1 | 95 | 66 |
| Aditus | 21 | 21 | 20 | 1 | 1 | 95 | 75 |
| Mastoid air cells | 19 | 21 | 19 | 0 | 3 | 86 | 100 |
| Per-lab cells | 6 | 3 | 3 | 3 | 0 | 100 | 86 |
Observations
The findings on CT i.e. presence of soft tissue density mass with or without bony erosions in the various designated regions, was compared with the operative findings for presence of cholesteatoma. Table 18 shows the distribution of these findings. The widening of,the aditus together with presence of soft tissue density mass was indicative of a presence of cholestetoma in that region. However, in the peril abyrinthine area, erosion of the cells alone was taken as an indicator of cholesteatoma. CT was 100% sensitive for cholesteatoma in protympanum, posterior tympanum, hypotmpanum and peril abyrinthine cells and sensitivity varied from 95% to 86% for other regions. CT was 100% specific for cholesteatoma in epitympanum and mastoid air cells and specificity varied from 86% to 66% for other regions (Fig. 9).
Table XX: Ossicular destruction
| Findings | CT Scan | Surgery | Cases in Agreement | False +VE | False -VE | Sensitivity | Specificity |
| Malleus:Handle | 13 | 15 | 13 | 0 | 3 | 81 | 100 |
| Malleus:Head | 11 | 16 | 11 | 0 | 4 | 73 | 100 |
| Incus | 15 | 17 | 14 | 1 | 3 | 82 | 87 |
Observations
CT diagnosed erosion of handle of malleus accurately in 13 of the 15 cases, who found to have erosion on surgery (Sensitivity 81 % and specificity 86%). It failed to identify the erosion of the head of the malleus in'4 of the 16 cases (sensitivity 73% and specificity 100%). CT diagnosed erosion of incus accurately in 14 of the 17 cases and failed to identify erosion in three cases and there was false positive interpretation in one case (Sensitivity 82% and specificity 87%) (Fig. 10).
Table XXI: Correlation of CT scan and operative findings
| Findings | CT Scan | Surgery | Cases in Agreement | False +ve | Fasle -ve | Sensitivity | Specificity |
| Ossicular destruction | 15 | 18 | 15 | 0 | 3 | 84 | 100 |
| Facial Canal Dehiscence | 4 | 3 | 2 | 2 | 1 | 60 | 90 |
| Lateral Semicircular Canal | 2 | 1 | 1 | 1 | 0 | 100 | 94 |
| Mastoid Cortex Dehiscence | 3 | 4 | 3 | 0 | 1 | 75 | 100 |
| Sibus plate dehiscence | 1 | 1 | 1 | 0 | 0 | 100 | 100 |
Observations
CT diagnosed dehisense of horizontal segment of facial canal accurately in 2 cases. There was false positive interpretation in two cases and it failed to identify the dehisence (sensitivity 60% and specificity 90%). It was 100% sensitivity and 95% specific for diagnosis of erosion of LSCS with only one false positive interpretation. Ct diagnosed mastoid cortex dehisence accurately in 3 cases and failed to identify in one case (sensitivity 75% and specificity 100%). It was 100% sensitive and specific for sinus plate dehisence (Fig. 11).
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