Congenital abnormalities of the temporal bone

Congenital

Abnormalities

of the Temporal

Bone

By MAY M. CLIFF, M.D., MARC S. LAPAYOWKER, M.D., AND HENRY J. WOLOSHIN, M.D.

ONGENITAL MALFORMATIONS of the ear are said to occur once in 3500 live births.” Less than 10 per cent are bilateral, and it is in these cases that there is a great need for improvement of hearing function. When there is complete or partial atresia of the external auditory canal, a direct otoscopic examination is not possible. Thus, roentgen studies become extremely valuable and are the only nonsurgical means of determining the status of the middle and inner ear. Since speech development usually begins prior to 2 years of age, it is of the utmost importance to the patient that some means of hearing should be present by this age if satisfactory speech is to be acquired. If testing shows that a hearing aid will be of any ben&t, it should be provided at about 6 months. Surgical correction can then be considered at about 18 to 24 months. A functioning cochlea must be present if surgery is to be performed; this can be ascertained preoperatively by bone conduction tests. Abnormalities of the external and middle ear are in a sense the most important because they are encountered most frequently and are amenable to surgical correction. If it is concluded after a complete audiologic, otologic, pediatric, and radiographic evaluation that that surgical repair is not feasible, the best training program for the patient is then determined. If hearing loss is irreversible, a language training program can be instituted that’ involves a multisensory approach to communication, including kinesthetic, visual, tactile, and auditory (if any hearing remains). In most cases with bony abnormalities of the inner ear associated with hearing loss, hearing aids have not been helpful.

C

EMBROYOLOGYOF THE TEMPORAL BONE Knowledge of the embryologic development of the inner, middle, and external ear is helpful in understanding the clinical and radiologic findings.l The auricle develops from the tissues around the first branchial arch, the external auditory meatus from the first branchial groove, the tympanic cavity and eustachian tube from the first pharyngeal pouch, the malleus and incus from the first branchial arch, and the stapes from the second branchial arch. The development of the inner ear from an ectodermal plate situated on each side of the hindbrain begins in the third week of intrauterine life and is independent of the development of the middle and external ear. This explains why malformations of the external and middle ear may be seen with a normal inner ear. From the Department of Radiology, Temple University Hospital, Philudelphiu, Pa. Supported in part by USPHS Grant 5T12-HE 05759-03. MAY M. CLIFF, M.D.: Assistant Professor of Radiology, Temple University Hospital, Philadelphia, Pa. MARC S. LAPAYOWKER,M.D.: Associate Professor of Radiology, Temple University Hospital, Philadelphia, Pa. HENRY J. WOLOSHIN, M.D.: Professor of Radiology, Temple University Hospital, Philudelphia, Pa. 122

SEMINARS IN ROFNTGENOLOGY, VOL. 4, No. 2 (APRIL),

1969

CONGENITAL ABNOFMALJTIES

Fig. L-Treacher-Collins syndrome. Absence of external auditory canal with upward displacement of temporomandibular joint (1); narrowed and deformed middle ear with no ossicles (2). All illustrations in this article are AP tomograms.

ABNORMALITIES

OF THE TEMPORAL

BONE: SYNDROMES

The Treacher-Collins syndrome (mandibulofacial dysostosis)4 is interesting embryologically; it consists of malformations of the external and middle ear associated with anomalies of other structures of the same embryologic derivation. There is malformation of the mandible and maxillae, outward and downward slant of the eyes, and notched lower lids. Thiese are due to arrested development of the whole first branchial groove and arch in the second month of fetal life. Stovin et a1.13reviewed 63 cases of this syndrome and found a wide variety of defects: microtia and defects of the auricles; stenosis or absence of the external auditory canals; middle ear abnormalities; inner ear defects; and deafness ( Fig. 1). Deafness of the middle ear type is an almost constant finding and, since newer developments in endaural surgery enable many patients to regain some function, careful analysis of the middle and inner ear structures by the radiologist is of great help to the otologist in planning the operation. In Hurler’s syndrome multiple abnormalities in the middle and inner ear have been discovered in one case. The ossicles have shown deformity with limitation of joint motion. McKusickll believes that the deafness is probably secondary to the bone disease. In osteogenesis imperfecta deafness is one of the more frequent findings. However, it is rarely complete, usually begins in the third decade, increases progressively with time, and is of an otosclerotic nature.4 Goldenhar’s syndrome (oculoauriculovertebral dysplasia) sometimes has absence or deficiency of the external auditory meatus. In Crouzon’s syndrome (craniofacial dysostosis) bilateral atresia of the auditory meatus has been noted. In hemifaciul microsomiu (otomandibular dysostosis and unilateral facial agenesis) malformation of the external ear and aplasia of the external auditory canal have been reported. It is & interest that in the few reported cases of aplasia of both mandibular condyles in this syndrome, no ear anomalies were observed. There is deafness in approximately 20 per cent of patients with the Waur& enburg syndrome (anomalies of eyebrows, lids, nasal root, heterochromia of

CLIFF, LAPAYOWKER AND WOLOSHIN

124

ternal auditory

canal are well &alized.

iris, white forelock) but this has been shown to be due to the absence of the organ of Corti. However, JensenG reported a 15 year old patient with this syndrome with total deafness o,f both ears who had an irregularly formed vestibule, abnormal shape of the lateral and superior semicircular canals, no oval window, absence of the posterior semicircular canal, and thickened labyrinthine walls. Congenital deafness in rubella patients was investigated by Friedmann and Wright.3 In their study of four temporal bones, they noted hemorrhage in the cochlea and inflammatory changes in the cochlear duct and organ of Corti. Deafness is also mentioned in trisomy 13-15, trisomy 6, Pierre Robin, KlippelFeil, Ullrich-Feichtiger, Mobius, and Hallerman-Streiff syndromes. The cause of deafness in these syndromes needs further investigation. ABNORMALITIES

OF THE TEMPORAL

BONE: ISOLATED

There are two common classifications of the tomographic findings in patients with ear malformations. Frey2 lists five groups, the first with solitary malformation of the ossicles and the remaining four grouped according to the size of be “atresia plate” which blocks the tympanic cavity laterally (Figs. 2 and 3). Valvassori classiiles congenital abnormalities of the temporal bone or partial atresia and in the following way: ( 1) external ear-complete dysplasia of the external auditory canal (Fig. 4); (2) middle ear-complete or partial atresia of the tympanic cavity (Fig. 5) ; absence, dysplasia, and fusion of the ossicles (Fig. 6), and absence of the oval window due to fusion of the footplate of the stapes; (3) inner ear-atresia of the internal auditory canal and abnormal position, angulation, and size of the semicircular canals (Fig. 7); (4) anomalies along the course of the facial nerve canal. In an examination of 50 children with congenital neurosensory deafness previously reported by us, 6 children (and one parent) had roentgenographic bony abnormalities .I0 These changes all involved the inner ear and included unilateral and bilateral narrowing of the internal auditory canal, marked shortening and widening of the internal auditory canal, absent cochlea, de-

CONGENITAL

ABNORMALITIES

Fig. 4.-Thick atresia plate (white arrow) occluding external auditory canal. Peculiar bulbous enlargement of lateral inferior portion of internal auditory canal (black arrow).

Fig.

6.-Deformed

ossicular

mass

(black arrow) is seen in normal position above a thick atresia plate (white arrow).

Fig. S.-Thick bony mass (anesia plate) replacing most of middle ear and external auditory canal (arrow).

Fig. ‘I.-Narrowed internal auditory canal (2). The vestibule and horizontal

semicircular canal are enlarged (1).

formed cochlea with only the outer coil seen (Fig. 8), and an enlarged deformed vestibule which encroached upon the lateral and superior semicircular canals (Figs. 9 and 10). In this study, only children with congenital neurosensory deafness who had no external auditory canal or pimra abnormalities were evaluated, and no cases of the syndromes listed above were studied, Since that report, we have seen many other abnormalities in various forms of deafness: atresia of the external auditory canal with an atresia plate; atresia of the tympanic cavity; deformed and laterally displaced ossicles (Fig. 11) ; anomalies along the course of the facial canal; and absence of development of the entire mastoid area and external auditory canal associated with an abnormal vestibule (Fig. 12). This group of children differed from the patients in our initial paper in that some had obvious external ear deformities and others had recognizable syndromes. Some of these additional patients had had severe infections in early childhood after which hearing loss was detected, but the radiologic findings were those of congenital bony abnormalities seen with congenital neurosensory deafness.

CLIFF,

Fig. 8.-Deformed saccular coclllea (arrow) in normal position. The remaining inner, middle, and external ear structures are normal.

Fig, lO.-Enlarged vestibule (arrow) and semicircular canals. Also noted is lateral narrowing of the internal auditory canal.

LAPIAYOWKER

AND

WOLOSHIN

Fig. 9.-Enlarged vestibule and horizontal semicircular canal (l), and narrowed internal auditory canal (2).

Fig. Il.-Enlargement and deformity of middle ear with inferior displacement of a deformed ossicular mass (arrow). The external auditory canal is also narrowed by an inferiorly placed roof.

Fig. U-Large deformed vestibule (black arrow) with complete absence of mastoid area (white arrow), external, and middle ear.

CONGENITAL

187

A~mo~w~Lrrm

LITERATUREREVIEW Terrahe14 carefully studied 37 children with malformed ears resulting from thalidomide. Frequently seen were cases of combined anomalies of the external, middle, and inner ear, as well as defects of the mid&le ear without external ear involvement. Facial nerve paralysis frequently associated with thalidomide malformations of the ear was not found to be due to compression of the nerve by a narrow facial canal. Inner ear abnormalities included dysplasia or aplasia of the lateral semicircular canal (frequent), involvement of more than one semicircular canal and the cochlea, rudimentary labyrinthine structures, and aplasia of the inner ear. Two isolated labryinths on the same side were seen and this is the first time such a finding has been reported. The internal auditory meatus frequently showed narrowing and occasionally widening. A great variety of middle ear anomalies was seen. Total aplasia of the tympanic cavity was rare, and abnormal widening was more frequently seen than narrowing. There were malformed ossicles and atretic plates causing lateral blockage of the tympanic cavity. Jensen and Rovsing8 examined 40 pateints with ear malformations by polytomography. They commented that the defects are more often localized EOthe right than tomthe left ear, which has also been our experience. Using Frey’s classification, they found a relationship between the extent of the malformation and the loss of hearing, but no correlation between the degree of pneumatization of the mastoids and the extent of the malformation. They concluded that conventional radiography was of no use in the evaluation of congenital ear malfomrations. Regarding the atresia plate and the size of the tympanic cavity, the radiographic and surgical findings in the 18 operated ears were completely in agreement. However, the radiologic diagnosis of ossicular deformity was disappointing: there was complete agreement in 11 cases, total disagreement in 3, and partial agreement in 4. This was felt to be due to the infrequent use of other than the AP views, and they now rrse at least two projections in all cases of malformations. The so-called Mondini defect is a deformity of the cochlea in which only the first one and a half coils are normal and there is a centrally located cavity. Some authors have consid,ered this to be the pathologic basis of dominant inherited deafness. Mondini first described it in 1791. In 1893, Mygind published a description of the Ibsen-Mackeprang collection of temporal bones from deaf children. Among 110 bones, he found 10 with the Mondini malformation. Jensen’ observed two cases of Mondini malformation in the first 14 deaf children he examined and demonstrated the radiologic findings. He stated that the lesion may not be visible on routine AP tomograms and suggested tomography perpendicular to the long axis of the petrous pyramid, projection. which he names the axial-pyramidal James et al5 studied 12 patients with external meatal atresia and observed that the mandibular fossa usually appeared larger and shallower than normal due to the absence of the anterior wall of the external auditory canal. We have also observed this finding.

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WOLOSHIN

Stool et al.” recently published interesting reports of two children with presumed congenital deafness. They had recurrent episodes of meningitis and rhinorrhea or otorrhea. On plain films, the vestibules and semicircular canals appeared enlarged. Pantopaque studies of the posterior fossa showed contrast entering the internal auditory canal, the vestibule, the middle ear, and then going out the eustachian tube, REFERENCES 1. Arey, L. B.: Developmental Anatomy. A Textbook and Laboratory Manual of Embryology (ed. 6). Philadelphia, W. B.

Saunders,1954. 2. Frey, K. UT.: Die Tomographie der Labyrinthmissbildungen. Fortschr. Roentgenstr. 102:1, 1965. 3. Friedman, I., and Wright, M. I.: Histopathological changes in the foetal and infantile inner ear caused by maternal rubella. Brit. Med. J. 2:20, 1966. 4. Gorlin, R. J., and Pindborg, J, J.: Syndromes of the Head and Neck. New York, McGraw-Hill Book Company, 1964. 5. James, J. A., Penry, J. B., and Ross, F. G. M.: Tomography in atresia of the external auditory meatus. Brit. J. Radial. 37:511, 1964. 6. Jensen, J.: Tomography of the inner ear in a case of Waardenburg’s syndrome. Amer. J. Roentgen. 101:828, 1967. 7. Jensen, J.: Tomography of the inner ear in deaf children. Radiological demonstration of two cases with the Mondini malfomration. J. Laryngol. 81:22, 1967. 8. Jensen, J., and Rovsing, H.: Tomo-

graphy in congenita! malformations of the middle ear. Radiology 90:268, 1968. 9. Kaseff, L. G.: Preoperative tomography of congenital malformations of the ear. Trans. Amer. Acad. Ophthal. Otolaryng. 70:59, 1966. 10. Lapayowker, M. S., Woloshin, H. J., Ronis, M. L., and Ronis, B. J.: Temporal bone abnormalities in congenital neurosensory deafness as revealed by plesiosectional tomography. Amer. J. Roentgen. 97: 125, 1966. 11. McKusick, V.: Heritable Disorders of Connecti,ve Tissue (ed. 2). St. Louis, C. V. Mosby Company, 1960. 12. Stool, S., Leeds, N. E., and Shulman, K,: The syndrome of congenital deafness and otic meningitis: Diagnosis and management. J. Pediat. ‘71:547, 1967. 13. Stovin, J. J., Lyon, J. A., Jr., and Clemmens, R. L.: Mandibulofacial dysostosis. Radiology 74:225, 1960. 14. Terrahe, K.: Malformations of the inner and middle ear due to thalidomide embryopathy. Results of tomography of the ear. Fortschr. Roentgenstr. 102:14, 1965.