NO. 6 EAR EXOSTOSES HRDLICKA 63 



For Roosa (1892) the growths are "in general caused by local 

 irritation." PoHtzer (1902) sees as their basis hypertrophic inflam- 

 mation of the lining of the canal, with ossification of the new tissue. 

 Virchow (1893) feels that they " owe their inception to a pathological 

 irritation restricted to the pars tympanica." For Green (1896) they 

 are " in most cases, in all probability, the results of a circumscribed 

 periostitis." For Goldstein (1898) "the most tangible and compre- 

 hensible cause, yet one not often met with, is that of the long-standing 

 direct irritation and chronic inflammatory condition of the walls of 

 the external auditory canal." McKenzie (1920, p. 458) holds that 

 " exostoses of the meatus seem to be the result of some long-continued 

 irritation, such as chronic suppuration of the middle ear, or eczema 

 of the meatal wall." For Michailowskij (1924, 1926) the chief cause 

 of ear exostoses is chronic otitis media and long-lasting dermatitis 

 of the auditory canal. Ballenger (1914, p. 661) tries thus to explain 

 the process: "Chronic suppuration of the middle ear may excite a 

 secondary inflammation of the membranous canal, and cause a fibrous 

 or connective tissue thickening, which, after a long period of time, 

 may be metamorphosed into osseous tissue." 



Many other authors, however, express doubt. Field (1878), al- 

 though acknowledging the influence of inflammatory conditions, never- 

 theless points out that there is a " rare form of exostosis of ivory con- 

 sistency, partaking of the nature of a new growth, and quite inde- 

 pendent of inflammatory changes." Kessel (1889, p. 287) and after 

 him Schlomka (1891, p. 15) acknowledge that the exostoses occur 

 most frequently in those with chronic ear discharges, and that the 

 discharge causes irritation is beyond doubt ; but often it is very hard 

 to decide which was the first condition, for it can be shown that the 

 exostoses are capable of arousing inflammation. Bezold (1895, p. 50) 

 found that " suppurative processes of the middle ear, as accompani- 

 ments of exostoses, belong to the great rarities." 



Korner (1904, pp. 102-104) feels that the causation of the hyper- 

 ostoses and exostoses of the meatus by other ear affections is a pos- 

 sibility only in very isolated instances and definitely proved in none ; 

 but " there is a rare variety of the exostoses that appears only in con- 

 sequence of chronic suppuration. These are small buttonlike, fairly 

 pedunculated growths that develop from the postero-superior border 

 of the meatus, close in front of or behind the suprameatal spine and 

 which therefore do not belong, as do the ordinary exostoses, to the 

 tympanic part, but to the squamous portion of the temporal bone." 

 Gray (1910, p. 137) cautions that "judgment must be reserved in 

 this matter " — a large number of the growths are without any 

 symptoms. 



