Otosclerosis involving the vestibular aqueduct and Meniere's disease TAE H. YOON, MD, MICHAEL M. PAPARELLA, MD, and PATRICIA A. SCHACHERN, Minneapolis, Minnesota The coexistence of otosclerosis and endolymphatic hydrops In the temporal bone have been described; however, the mechanism for the development of endolymphatic hy drops In otosclerosis remains unknown. Among 128 temporal bones with otosclerosis, Involvement of the vestibular aqueduct by otosclerosis was observed In four temporal bones from two patients. In all four, the vestibular aqueduct was filled with active otoscleroflc foci; the lumen of the endolymphatic duct a n d sac was narrowed as a result of flbrosls, a n d endolymphatic hydrops, more severe In the pars Inferior than the pars superior, was observed. Collapse of the ductus reunions and dilated saccule was seen In three temporal bones. Our study Indicates that otoscleroflc obstruction of the vestibular aqueduct may create a disturbance of the outflow and/or absorption of endolymph, leading to the development of endolymphatic hydrops a n d Meniere's disease, thus supporting the theory of longitudinal flow of endolymph. (OTOLARYNGOL HEAD NECK SURG 1990:103:107.)
M e n i e r e ' s disease is characterized by a symptomcomplex of vestibular symptoms, cochlear symptoms, and aural pressure. Endolymphatic hydrops is the main histopathologic finding in Meniere's disease and malabsorption of endolymph in the endolymphatic duct and sac may be the fundamental problem. 1 ' 2 The etiology of Meniere's disease is not fully understood; how ever, otosclerosis has been described as one of the causes.'· 2 Although the coexistence of otosclerosis and endo lymphatic hydrops has been described in a few studies of human temporal bones, 3 " 7 the mechanism of endo lymphatic hydrops in otosclerosis is still unknown. In a study of human temporal bones, it has been suggested that otosclerotic involvement of the vestibular aque-
duct, although rare, can create a dysfunction of endo lymph absorption, leading to hydrops.8 The theory of longitudinal flow of endolymph has been supported by animal studies in which endolymphatic hydrops was observed after obliteration of either the endolymphatic duct and sac, or the ductus reuniens.9·10 Herein we de scribe four temporal bones with otosclerosis that in volves the vestibular aqueduct, resulting in Meniere's disease with severe endolymphatic hydrops, with or without collapse of the dilated saccule. The mechanism of endolymphatic hydrops in otosclerosis involving the vestibular aqueduct, and the mechanism by which a dilated saccule may collapse, are discussed. CASi REPORTS Casel
From the Otopathology Laboratory, Department of Otolaryngology, University of Minnesota School of Medicine (Drs. Yoon and Paparella and Ms. Schachern), and the Minnesota Ear, Head, and Neck Clinic (Dr. Paparella). Supported (in part) by the National Institute for Neurological and Communicative Disorders and Stroke (grant no. 14538), the In ternational Foundation, and the Deafness Research Foundation. Presented at the Annual Meeting of the American Neurotology So ciety, San Francisco, Calif., March 31-April 1, 1989. Submitted for publication March 31, 1989; revision received Aug. 26, 1989; accepted Aug. 30, 1989. Reprint requests: Tae H. Yoon, MD, Otopathology Laboratory, De partment of Otolaryngology, Box 396 UMHC, University of Min nesota, Minneapolis, MN 55455. 23/1/16460
Clinical Information. This case involved a 78-year-old woman who died from unknown causes. She reported hearing loss and tinnitus bilaterally at 18 years of age. Her hearing became worse after an infection with mumps at age 22, and severe hearing loss developed at age 40. Since the age of 45, she had occasionally experienced severe attacks of spinning vertigo with nausea, especially when she bent over. At times she could not get out of bed for 4 or 5 days at a time. Audiometrie evaluation at age 60 revealed total hearing loss in the left ear and profound sensorineural hearing loss in the right ear. At the age of 74, she had attacks of vertigo that lasted 2 to 3 hours. Histopathologic findings In temporal bone. His topathologic findings were similar in both temporal bones. The external and middle ears appeared normal. Multiple oto sclerotic foci were seen in the oval window, bony labyrinth
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ΡΙς. 1. Case 1, A, Multiple otosclerotic foci seen In the endosteum of the cochlea, vestibule, semi circular canals, facial canal, anterior wall of the internal auditory canal, and vestibular aqueduct In the left ear. Severe endolymphatlc hydrops exists In all turns of the cochlea (arrows), saccule (s), and utricle (u). (Hematoxylln-eosln stain; original magnification x 8.) B, Left vestibular aqueduct (arrows) shows complete obliteration of the lumen by flbrosls. (Hematoxylln-eosin stain; original magnification x 24.) C, Right endolymphatlc duct (arrows) shows complete obliteration of the lumen by flbrosls. (Hematoxylln-eosin stain; original magnification x 58.) D, Left endolymphatlc sac (arrows) shows narrowing of the lumen by flbrosls. (Hematoxylln-eosln stain; original magnification x 58.)
of the cochlea, vestibule and semicircular canals, round win dow, outer wall of the interal auditory canal, facial canal, and vestibular aqueduct (Fig. 1, A). Most of these foci ap peared to be in an active stage, being very vascular, with a large number of osteoclasts and histiocytes. The vestibular aqueduct was filled with active otosclerotic foci, from its internal aperture to the rugose portion of the sac (Fig. 1, B). The lumen of the endolymphatlc duct and sac was markedly narrowed as a result of fibrosis (Fig. 1, C and D). There was no evidence of vasculitis or inflammatory infiltrate in the subepithelial tissue of the endolymphatlc sac. Active otosclerotic foci involved the endosteum of the mid dle and basal turns of the cochlear capsule. Between the mid dle and basal turns of the cochlea, the interscalar septum was fractured. Fibrosis of the scala tympani with herniation of the basilar membrane was observed in the middle turn of the left cochlea, but not in the right. Otosclerotic protrusion into the scala tympani was seen in the basal turn. Severe hydrops was seen in all turns of the cochlea (Fig. 1, A). In the apical turn, Reissner's membrane hemiated through the helicotrema into
the scala tympani; however, there was no rupture of Reissner's membrane throughout the cochlea. The organ of Corti ap peared slightly degenerated, with some loss of hair cells. The stria vascularis showed severe atrophy in the left ear, but mild atrophy in the right, in all turns. There were moderate atrophie and fibrotic changes in the spiral ligament. Marked loss of cochlear neurons and nerve fibers was observed in most turns, and the modiolus showed fibrotic changes. Otosclerotic foci completely involved the footplate of the stapes. The saccular wall was markedly dilated. The dilated saccule was collapsed onto the saccular macula in the anterior portion and adherent to the utricular wall in the posterior portion (Figure 2, Λ). The dilated cochlear duct herniated into the vestibule in the right ear. The macula of the saccule was slightly degenerated and appeared cyst-like in structure. The saccular otolithic membrane was degenerated. The utri cular wall was markedly dilated, the wall of the semicircular canals mildly dilated, and their sensory epithelium slightly degenerated. The posterior semicircular wall was ruptured in the right ear. The utricular duct was dilated at the level of the
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Fig. 2. Case 1. A, The dilated saccular wall (s) shows collapse onto the saccular macula (arrows) In the left ear. (Hematoxylln-eosln stain; original magnification x 15.) B, The ductus reuniens (short arrow) surrounded with otosclerotic foci and abnormal basophillc deposits in the right ear. The lumen of the ductus reuniens is collapsed. Severe endolymphatic hydrops (arrows) is seen at the hook end of the cochlear duct. (Hematoxylin-eosin stain; original magnification x 24.)
Fig. 3. Case 2. A, Multiple otosclerotic foci involving entire otic capsule, facial canal, internal auditory canal, and vestibular aqueduct in the right ear. Severe endolymphatic hydrops (arrows) seen in all turns of the cochlea and new bone formation (asterisk) seen In the scala tympani of the basal turn. (Hematoxylin-eosin stain; original magnification x 8.) B, Left endolymphatic duct (arrows) shows marked narrowing of the lumen by fibrosls. (Hematoxylin-eosin stain; original magnification x 58.)
utriculoendolymphatic valve. Otosclerotic foci were observed around the lumen of the ductus reuniens and the lumen was markedly narrowed and collapsed in both ears (Figure 2, B). The ductus reuniens was surrounded with abnormal basophilic deposits in the right ear. The vestibular and cochlear nerves were destroyed during removal of the temporal bones.
Case 2 Clinical Information. This case involved a 77-year-old woman who died of metastatic carcinoma of the lung. She had bilateral hearing loss when she was 20 years old. Fluc tuating hearing loss, fullness, and tinnitus developed later. When she was 56, her hearing became worse and hearing tests revealed no response to pure tones in either ear at max imum output of the audiometer at 100 dB. She was hospi talized for severe vertigo at the age of 64. Neurologic ex
amination conducted at this time was positive for the eighth nerve and the woman was diagnosed as having Meniere's disease. She continued to have recurrent bouts of vertigo, with nausea, vomiting, and tinnitus, and was treated with vasodilating medications.
Hlstopathologic findings in temporal bone. Histopathologic findings were similar in both temporal bones. The external and middle ears appeared normal. Multiple oto sclerotic foci were seen in the oval window, bony labyrinth of the cochlea, vestibule, semicircular canals, round window, anterior wall of the internal auditory canal, and vestibular aqueduct (Fig. 3, A). The vestibular aqueduct was involved by active otosclerotic foci from the internal aperture to the rugose portion of the endolymphatic sac. The lumen of the endolymphatic duct and the rugose portion of the endolym phatic sac appeared narrowed with fibrosis, but not completely
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Flg. A. Case 2. A, The saccular wall (s) Is markedly dilated and attached to the stapedlal footplate (arrows) In the left ear. B, The markedly dilated saccular wall Is attached onto the anterior portion of the stapedlal footplate (long arrow), and collapsed onto the saccular macula (short arrows) In the right ear. Note the rupture of saccular wall (open arrowhead). C, The lumen of the ductus reunlens Is collapsed (open arrowhead) In the right ear. Severe endolymphatic hydrops (arrows) seen at the hook end of the cochlea. Note the absence of otosclerotlc foci around the ductus reunlens. (A, B, and C of Fig. 4 were viewed with hematoxylln-eosln stain; original magnification x 24.)
obstructed (Fig. 3, B). The subepithelial tissue of the en dolymphatic sac was fibrotic without vasculitis or inflam matory infiltrate. The cochlear capsule was entirely involved and distorted because of otoslerotic foci. Between the apical and middle turns of the cochlea, a fracture was noted on the interscalar septum. Fibrosis in the scala tympani and distortion of the basilar membrane were observed in the midddle turn of the left cochlea; new bone formation was seen in the scala tym pani of the middle and basal turns of the right cochlea. Marked cochlear hydrops was observed in all turns, but there was no rupture of Reissner's membrane (Fig. 3, A). The organ of Corti showed mild atrophie changes in the left ear and severe atrophie changes in the right. The stria vascularis was severely atrophied in all turns. Moderate loss of cochlear neurons and nerve fibers was observed in most turns, and the modiolus showedfibroticchanges. The footplate of the stapes was free of otoslerotic involve ment in both ears, except for the anterior and posterior mar gins of the footplate. The dilated saccule was attached to the
stapedial footplate in the left ear (Fig. 4, A), but in the right ear the dilated saccule was collapsed onto the saccular macula and was partially ruptured (Fig. 4, B). The macula of the saccule showed moderate degenerative changes and the sac cular otoconial membrane was absent. The utricle was slightly dilated, but the sensory epithelium appeared normal. The wall of the semicircular canals and sensory cells appeared normal. The lumen of the ductus reuniens was not detected in the left ear, but was narrowed in the right ear (Fig. 4, C). However, no otosclerotic foci were observed in this area. The vestibular and cochlear nerves in the internal auditory canal appeared normal. DISCUSSION The coexistence of otosclerosis and endolymphatic hydrops is generally considered to be rare and coinci dental. Cases of otosclerosis with hydrops have been reported,3"7 but none of these studies described oto sclerotic involvement of the vestibular aqueduct. A
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previous report from our laboratory documented 95 tem poral bones with otosclerosis, of which six had endo lymphatic hydrops and two had otosclerotic involve ment of the vestibular aqueduct.8 Currently, our col lection contains 128 temporal bones with otosclerosis, of which 10 have severe endolymphatic hydrops and four have otosclerotic involvement of the vestibular aqueduct. In this study, we described our findings in these four temporal bones (2 cases) with otosclerotic involvement of the vestibular aqueduct resulting in Me niere's disease. Both of these cases had quite similar clinical features, with cochlear symptoms starting in early life and severe vestibular symptoms developing later. Otosclerotic involvement of the vestibular aqueduct can produce endolymphatic hydrops and Meniere's dis ease by three possible mechanisms: immunologie changes, biochemical changes, and/or obstructive histopathologic changes. Immunologie changes in the in ner ear are considered a mechanism for otosclerotic hydrops. An immune-mediated pathogenesis with type II collagen has been postulated in otosclerosis and Me niere's disease," but evidence of an immune-mediated process in either otosclerosis or Meniere's disease has not been demonstrated.12 In the present study, we did not observe immune-mediated histopathologic findings, such as infiltration of inflammatory cells or vasculitis in the endolymphatic sac. Biochemical changes in the inner ear fluids are an other consideration for otosclerotic hydrops. It has been reported that the enzymatic composition of the labyrin thine fluids may be changed in otosclerosis.13 The al terations in enzymatic activity in the cochlea could play a role in regulating ion transport into the scala media.14 A disturbance in ion balance between production and résorption of endolymph has been reported to be the primary cause of endolymphatic hydrops.1S On the other hand, ionic concentrations in the scala tympani and scala media have been found to be significantly altered in experimental hydrops.16 Although biochemical changes in the labyrinthine fluids in otosclerosis may play a role in the development of endolymphatic hy drops, it is still unknown whether these biochemical changes are caused by a direct enzymatic effect of oto sclerosis or by a secondary alteration in the composition of the labyrinthine fluids as a result of otosclerotic ob struction of the vestibular aqueduct. If the biochemical changes were caused by a direct enzymatic effect of the otosclerosis, one would expect that the hydrops would be related to the size and activity of the oto sclerotic foci. We did not observe this in our collection of otosclerotic bones.
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Otosclerotic obstruction of the vestibular aqueduct may cause histopathologic changes of the endolym phatic duct and sac, the vestibular aqueduct, or the periaqueductal area. These histopathologic changes could directly disturb the flow and absorption of en dolymph in the endolymphatic duct and sac or indirectly disturb the drainage of the venous system of the peri aqueductal area, thereby producing the hydrops. Perisaccularfibrosis,17sclerotic changes around the duct,18 narrowing of the lumen in the endolymphatic duct,19 loss of epithelial integrity and atrophy of the sac,20 small vestibular aqueduct,21 and a narrow external aperture of the vestibular aqueduct22 have been observed in Meniere's disease. Abnormal venous drainage via the paravestibular canaliculi has also been suggested as an important mechanism in Meniere's disease.23 We ob served obstructive histopathologic changes, including marked narrowing of the lumen of the endolymphatic duct and sac resulting fromfibrosisin all four temporal bones. Our findings indicate that otosclerotic involve ment of the vestibular aqueduct by obstructive histo pathologic changes can disturb theflowand /or absorp tion of endolymph in the endolymphatic duct and sac, and result in hydrops. Severe endolymphatic hydrops was observed in the cochlea and the vestibule in all four temporal bones in the present study, collapse of the dilated saccule was observed in three of the four bones, and collapse of the ductus reuniens was observed in all of these three. Although cochlear hydrops is described as a common finding in temporal bones with Meniere's disease, stud ies of the disease in human temporal bones have shown various saccular pathologies.24·25 In a study of 19 tem poral bones with Meniere's disease,24 saccular hydrops was observed in all cases. In another study of 22 tem poral bones with Meniere's disease,25 saccular hydrops was observed in 19 cases and saccular collapse in two cases. In animal studies, hydrops in both the cochlea and saccule has commonly been observed after obli teration of the endolymphatic duct and sac,9 but—after obliteration of the ductusreuniens—cochlearhydrops, saccular collapse, and a normal utricle have been found in the majority of cases.10 Although collapsed saccule and ductus reuniens have been observed in human tem poral bones with cochlear hydrops, the mechanism for collapse is still unknown.26 Collapse of the dilated saccule, with severe oto sclerotic foci on the stapedial footplate and otosclerotic foci and/or abnormal basophilic deposits around the ductus reuniens, were observed in both ears of case 1. In therightear of case 2, however, collapse and partial rupture of the dilated saccule were observed without
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otosclerotic involvement in the stapedial footplate or die ductus reuniens. It has been reported that abnormal crystalline deposits in the cochlear duct are associated with abnormal labyrinthine fluid dynamics in otoscler otic hydrops with saccular collapse.6 It is possible that collapse of the dilated saccule is related to an alteration in the composition of the labyrinthine fluids through enzymatic reactions of active otosclerosis—especially involving the stapedial footplate—or to obstruction of the ductus reuniens by otosclerosis and /or basophilic deposits as in case 1, and (as in case 2) is related to rupture of the overexpanded saccule or collapse of the ductus reuniens. In conclusion, otosclerotic involvement of the vestibular aqueduct has been demonstrated to cause a nar rowing of lumen byfibrosisin the endolymphatic duct and sac. This may disturb the outflow and/or absorption of endolymph, probably leading to endolymphatic hy drops, a histologie finding frequently associated with Meniere's disease, a clinical entity these subjects may have had. Our findings support the theory of longitu dinal fluid of endolymph. Further studies of temporal bones in humans are needed to clarify the mechanism by which otosclerosis may involve the vestibular aq ueduct and lead to endolymphatic hydrops. We wish to thank Noriko Morizono for processing of his tologie sections, Sherry Lamey for the photography, and JoAnn Knox for preparation of the manuscript. REFERENCES 1. PaparellaMM. Pathology of Meniere's disease. Ann Otol Rhinol Laryngol 1984;93:31-5. 2. Paparella MM. Pathogenesis of Meniere's disease and Meniere's syndrome. Acta Otolaryngol 1984:10-26. 3. Black FD, Sando I, Hildyard VH, Hemenway WG. Bilateral multiple otosclerotic foci and endolymphatic hydrops: histological case report. Ann Otol-Rhinol Laryngol 1969;78:1062-73. 4. Igarashi M, Jerger S, O-Uchi T, Alford BR. Fluctuating hearing loss and recurrent vertigo in otosclerosis: an audiologic and tem poral bone study. Arch Otorhinolaryngol 1982;236:161-71. 5. Johnsson LG, Hawkins JE Jr, Linthicum FH Jr. Cochlear and vestibular lesions in capsular otosclerosis as seen in microdis section. Ann Otol Rhinol Laryngol 1978;87:1-40. 6. Johnsson LG, Hawkins JE Jr, Fouse RC, et al. Cochlear and otoconial abnormalities in capsular otosclerosis with hydrops. Ann Otol Rhinol Laryngol 1982;91:3-15. 7. Schuknecht HF, Gulya AJ. Endolymphatic hydrops: an overview and classification. Ann Otol Rhinol Laryngol 1983;92:1-20. 8. Liston SL, Paparella MM, Mancini F, Anderson JH. Otosclerosis and endolymphatic hydrops. Laryngoscope 1984;94:1003-7.
9. Kimura RS. Experimental blockage of the endolymphatic duct and sac and its effect on the inner ear of the guinea pig: a study of endolymphatic hydrops. Ann Otol Rhinol Laryngol 1967;76:664-87. 10. Kimura RS, Schuknecht HF, Ota CY, Jones DD. Obliteration of the ductus reuniens. Acta Otolaryngol 1980;89:295-309. 11. Yoo TJ, Stuart JM, Rang AH, Townes AS, Tomoda K, Dixit S. Type II collagen autoimmunity in otosclerosis and Meniere's disease. Science 1982;217:1153-5. 12. Nadol JB Jr, McKenna MS. Histopathology of Meniere's disease and otosclerosis: relevance of possible immune-mediated patho genesis. In: Veldman JE, ed. Immunobiology, histopathology, and tumor immunology in otolaryngology. Proceedings Second International Academic Conference, Utrecht, The Netherlands, August 26-29, 1986. Amsterdam: Kugler Publication, 1987;16584. 13. Chevance LG, Causse J, Bretlau P, Jörgensen MB, Berges J. Hydrolytic activity of the perilymph in otosclerosis; a preliminary report. Acta Otolaryngol 1972;74:23-8. 14. Ross MD, Ernst SA, Kerr TP. Possible functional roles of Na + , K+-ATPase in the inner ear and their relevance to Meniere's disease. J Otolaryngol 1982;3:353-60. 15. Vosteen KH, Morgenstern. Biochemical aspects of inner pathophysiology. In: Pfaltz CR, ed. Controversial aspects of Meniere's disease. New York: New York Thieme, Inc., 1986:16-28. 16. Cohen J, Morizono T. Changes in EP and inner ear ionic con centrations in experimental endolymphatic hydrops. Acta Oto laryngol 1984;98:398-402. 17. Zechner G, Altmann F. Histological studies on the human en dolymphatic duct and sac. Pract Oto-rhino-laryngol 1969;3l: 65-83. 18. Sakai N, Igarashi M, Ohashi K, Ishii M. Sclerotic changes around the endolymphatic sac in human temporal bones. Arch Otolaryngol 1985;242:315-20. 19. Ikeda M, Sando I. Endolymphatic duct and sac in patients with Meniere's disease: a temporal bone histopathological study. Ann Otol Rhinol Laryngol 1984;93:540-6. 20. Arenberg IK, Marovitz WF, Shambough GI Jr. The rale of the endolymphatic sac in the pathogenesis of the endolymphatic hy drops in man. Acta Otolaryngol 1970;76:1-49. 21. Sando I, Ikeda M. The vestibular aqueduct in patients with Me niere's disease: a temporal bone histopathological study. Acta Otolaryngol 1984;97:558-70. 22. Stahle J, Wibrand HF. The temporal bone in patients with Me niere's disease. Acta Otolaryngol 1983;95:81-94. 23. Güssen R. Vascular mechanism in Meniere's disease. Acta Oto laryngol 1982;108:544-9. 24. Antoli-Candela F. The histopathology of Meniere's disease. Acta Otolaryngol 1976;82:5-42. 25. Okuno T, Sando I. Localization, frequency, and severity of en dolymphatic hydrops and the pathology of the labyrinthine mem brane in Meniere's disease. Ann Otol Rhinol Laryngol 1987: 438-45. 26. Kitamura KK, Schuknecht HF, Kimura RS. Cochlear hydrops in association with collapsed saccule and ductus reuniens. Ann Otol Rhinol Laryngol 1982;91:5-13.
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M e n i e r e ' s disease is characterized by a symptomcomplex of vestibular symptoms, cochlear symptoms, and aural pressure. Endolymphatic hydrops is the main histopathologic finding in Meniere's disease and malabsorption of endolymph in the endolymphatic duct and sac may be the fundamental problem. 1 ' 2 The etiology of Meniere's disease is not fully understood; how ever, otosclerosis has been described as one of the causes.'· 2 Although the coexistence of otosclerosis and endo lymphatic hydrops has been described in a few studies of human temporal bones, 3 " 7 the mechanism of endo lymphatic hydrops in otosclerosis is still unknown. In a study of human temporal bones, it has been suggested that otosclerotic involvement of the vestibular aque-
duct, although rare, can create a dysfunction of endo lymph absorption, leading to hydrops.8 The theory of longitudinal flow of endolymph has been supported by animal studies in which endolymphatic hydrops was observed after obliteration of either the endolymphatic duct and sac, or the ductus reuniens.9·10 Herein we de scribe four temporal bones with otosclerosis that in volves the vestibular aqueduct, resulting in Meniere's disease with severe endolymphatic hydrops, with or without collapse of the dilated saccule. The mechanism of endolymphatic hydrops in otosclerosis involving the vestibular aqueduct, and the mechanism by which a dilated saccule may collapse, are discussed. CASi REPORTS Casel
From the Otopathology Laboratory, Department of Otolaryngology, University of Minnesota School of Medicine (Drs. Yoon and Paparella and Ms. Schachern), and the Minnesota Ear, Head, and Neck Clinic (Dr. Paparella). Supported (in part) by the National Institute for Neurological and Communicative Disorders and Stroke (grant no. 14538), the In ternational Foundation, and the Deafness Research Foundation. Presented at the Annual Meeting of the American Neurotology So ciety, San Francisco, Calif., March 31-April 1, 1989. Submitted for publication March 31, 1989; revision received Aug. 26, 1989; accepted Aug. 30, 1989. Reprint requests: Tae H. Yoon, MD, Otopathology Laboratory, De partment of Otolaryngology, Box 396 UMHC, University of Min nesota, Minneapolis, MN 55455. 23/1/16460
Clinical Information. This case involved a 78-year-old woman who died from unknown causes. She reported hearing loss and tinnitus bilaterally at 18 years of age. Her hearing became worse after an infection with mumps at age 22, and severe hearing loss developed at age 40. Since the age of 45, she had occasionally experienced severe attacks of spinning vertigo with nausea, especially when she bent over. At times she could not get out of bed for 4 or 5 days at a time. Audiometrie evaluation at age 60 revealed total hearing loss in the left ear and profound sensorineural hearing loss in the right ear. At the age of 74, she had attacks of vertigo that lasted 2 to 3 hours. Histopathologic findings In temporal bone. His topathologic findings were similar in both temporal bones. The external and middle ears appeared normal. Multiple oto sclerotic foci were seen in the oval window, bony labyrinth
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ΡΙς. 1. Case 1, A, Multiple otosclerotic foci seen In the endosteum of the cochlea, vestibule, semi circular canals, facial canal, anterior wall of the internal auditory canal, and vestibular aqueduct In the left ear. Severe endolymphatlc hydrops exists In all turns of the cochlea (arrows), saccule (s), and utricle (u). (Hematoxylln-eosln stain; original magnification x 8.) B, Left vestibular aqueduct (arrows) shows complete obliteration of the lumen by flbrosls. (Hematoxylln-eosin stain; original magnification x 24.) C, Right endolymphatlc duct (arrows) shows complete obliteration of the lumen by flbrosls. (Hematoxylln-eosin stain; original magnification x 58.) D, Left endolymphatlc sac (arrows) shows narrowing of the lumen by flbrosls. (Hematoxylln-eosln stain; original magnification x 58.)
of the cochlea, vestibule and semicircular canals, round win dow, outer wall of the interal auditory canal, facial canal, and vestibular aqueduct (Fig. 1, A). Most of these foci ap peared to be in an active stage, being very vascular, with a large number of osteoclasts and histiocytes. The vestibular aqueduct was filled with active otosclerotic foci, from its internal aperture to the rugose portion of the sac (Fig. 1, B). The lumen of the endolymphatlc duct and sac was markedly narrowed as a result of fibrosis (Fig. 1, C and D). There was no evidence of vasculitis or inflammatory infiltrate in the subepithelial tissue of the endolymphatlc sac. Active otosclerotic foci involved the endosteum of the mid dle and basal turns of the cochlear capsule. Between the mid dle and basal turns of the cochlea, the interscalar septum was fractured. Fibrosis of the scala tympani with herniation of the basilar membrane was observed in the middle turn of the left cochlea, but not in the right. Otosclerotic protrusion into the scala tympani was seen in the basal turn. Severe hydrops was seen in all turns of the cochlea (Fig. 1, A). In the apical turn, Reissner's membrane hemiated through the helicotrema into
the scala tympani; however, there was no rupture of Reissner's membrane throughout the cochlea. The organ of Corti ap peared slightly degenerated, with some loss of hair cells. The stria vascularis showed severe atrophy in the left ear, but mild atrophy in the right, in all turns. There were moderate atrophie and fibrotic changes in the spiral ligament. Marked loss of cochlear neurons and nerve fibers was observed in most turns, and the modiolus showed fibrotic changes. Otosclerotic foci completely involved the footplate of the stapes. The saccular wall was markedly dilated. The dilated saccule was collapsed onto the saccular macula in the anterior portion and adherent to the utricular wall in the posterior portion (Figure 2, Λ). The dilated cochlear duct herniated into the vestibule in the right ear. The macula of the saccule was slightly degenerated and appeared cyst-like in structure. The saccular otolithic membrane was degenerated. The utri cular wall was markedly dilated, the wall of the semicircular canals mildly dilated, and their sensory epithelium slightly degenerated. The posterior semicircular wall was ruptured in the right ear. The utricular duct was dilated at the level of the
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Fig. 2. Case 1. A, The dilated saccular wall (s) shows collapse onto the saccular macula (arrows) In the left ear. (Hematoxylln-eosln stain; original magnification x 15.) B, The ductus reuniens (short arrow) surrounded with otosclerotic foci and abnormal basophillc deposits in the right ear. The lumen of the ductus reuniens is collapsed. Severe endolymphatic hydrops (arrows) is seen at the hook end of the cochlear duct. (Hematoxylin-eosin stain; original magnification x 24.)
Fig. 3. Case 2. A, Multiple otosclerotic foci involving entire otic capsule, facial canal, internal auditory canal, and vestibular aqueduct in the right ear. Severe endolymphatic hydrops (arrows) seen in all turns of the cochlea and new bone formation (asterisk) seen In the scala tympani of the basal turn. (Hematoxylin-eosin stain; original magnification x 8.) B, Left endolymphatic duct (arrows) shows marked narrowing of the lumen by fibrosls. (Hematoxylin-eosin stain; original magnification x 58.)
utriculoendolymphatic valve. Otosclerotic foci were observed around the lumen of the ductus reuniens and the lumen was markedly narrowed and collapsed in both ears (Figure 2, B). The ductus reuniens was surrounded with abnormal basophilic deposits in the right ear. The vestibular and cochlear nerves were destroyed during removal of the temporal bones.
Case 2 Clinical Information. This case involved a 77-year-old woman who died of metastatic carcinoma of the lung. She had bilateral hearing loss when she was 20 years old. Fluc tuating hearing loss, fullness, and tinnitus developed later. When she was 56, her hearing became worse and hearing tests revealed no response to pure tones in either ear at max imum output of the audiometer at 100 dB. She was hospi talized for severe vertigo at the age of 64. Neurologic ex
amination conducted at this time was positive for the eighth nerve and the woman was diagnosed as having Meniere's disease. She continued to have recurrent bouts of vertigo, with nausea, vomiting, and tinnitus, and was treated with vasodilating medications.
Hlstopathologic findings in temporal bone. Histopathologic findings were similar in both temporal bones. The external and middle ears appeared normal. Multiple oto sclerotic foci were seen in the oval window, bony labyrinth of the cochlea, vestibule, semicircular canals, round window, anterior wall of the internal auditory canal, and vestibular aqueduct (Fig. 3, A). The vestibular aqueduct was involved by active otosclerotic foci from the internal aperture to the rugose portion of the endolymphatic sac. The lumen of the endolymphatic duct and the rugose portion of the endolym phatic sac appeared narrowed with fibrosis, but not completely
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Flg. A. Case 2. A, The saccular wall (s) Is markedly dilated and attached to the stapedlal footplate (arrows) In the left ear. B, The markedly dilated saccular wall Is attached onto the anterior portion of the stapedlal footplate (long arrow), and collapsed onto the saccular macula (short arrows) In the right ear. Note the rupture of saccular wall (open arrowhead). C, The lumen of the ductus reunlens Is collapsed (open arrowhead) In the right ear. Severe endolymphatic hydrops (arrows) seen at the hook end of the cochlea. Note the absence of otosclerotlc foci around the ductus reunlens. (A, B, and C of Fig. 4 were viewed with hematoxylln-eosln stain; original magnification x 24.)
obstructed (Fig. 3, B). The subepithelial tissue of the en dolymphatic sac was fibrotic without vasculitis or inflam matory infiltrate. The cochlear capsule was entirely involved and distorted because of otoslerotic foci. Between the apical and middle turns of the cochlea, a fracture was noted on the interscalar septum. Fibrosis in the scala tympani and distortion of the basilar membrane were observed in the midddle turn of the left cochlea; new bone formation was seen in the scala tym pani of the middle and basal turns of the right cochlea. Marked cochlear hydrops was observed in all turns, but there was no rupture of Reissner's membrane (Fig. 3, A). The organ of Corti showed mild atrophie changes in the left ear and severe atrophie changes in the right. The stria vascularis was severely atrophied in all turns. Moderate loss of cochlear neurons and nerve fibers was observed in most turns, and the modiolus showedfibroticchanges. The footplate of the stapes was free of otoslerotic involve ment in both ears, except for the anterior and posterior mar gins of the footplate. The dilated saccule was attached to the
stapedial footplate in the left ear (Fig. 4, A), but in the right ear the dilated saccule was collapsed onto the saccular macula and was partially ruptured (Fig. 4, B). The macula of the saccule showed moderate degenerative changes and the sac cular otoconial membrane was absent. The utricle was slightly dilated, but the sensory epithelium appeared normal. The wall of the semicircular canals and sensory cells appeared normal. The lumen of the ductus reuniens was not detected in the left ear, but was narrowed in the right ear (Fig. 4, C). However, no otosclerotic foci were observed in this area. The vestibular and cochlear nerves in the internal auditory canal appeared normal. DISCUSSION The coexistence of otosclerosis and endolymphatic hydrops is generally considered to be rare and coinci dental. Cases of otosclerosis with hydrops have been reported,3"7 but none of these studies described oto sclerotic involvement of the vestibular aqueduct. A
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Volume 103 Number 1 July 1990
Otosclerosis Involving vestibular aqueduct and Meniere's disease
previous report from our laboratory documented 95 tem poral bones with otosclerosis, of which six had endo lymphatic hydrops and two had otosclerotic involve ment of the vestibular aqueduct.8 Currently, our col lection contains 128 temporal bones with otosclerosis, of which 10 have severe endolymphatic hydrops and four have otosclerotic involvement of the vestibular aqueduct. In this study, we described our findings in these four temporal bones (2 cases) with otosclerotic involvement of the vestibular aqueduct resulting in Me niere's disease. Both of these cases had quite similar clinical features, with cochlear symptoms starting in early life and severe vestibular symptoms developing later. Otosclerotic involvement of the vestibular aqueduct can produce endolymphatic hydrops and Meniere's dis ease by three possible mechanisms: immunologie changes, biochemical changes, and/or obstructive histopathologic changes. Immunologie changes in the in ner ear are considered a mechanism for otosclerotic hydrops. An immune-mediated pathogenesis with type II collagen has been postulated in otosclerosis and Me niere's disease," but evidence of an immune-mediated process in either otosclerosis or Meniere's disease has not been demonstrated.12 In the present study, we did not observe immune-mediated histopathologic findings, such as infiltration of inflammatory cells or vasculitis in the endolymphatic sac. Biochemical changes in the inner ear fluids are an other consideration for otosclerotic hydrops. It has been reported that the enzymatic composition of the labyrin thine fluids may be changed in otosclerosis.13 The al terations in enzymatic activity in the cochlea could play a role in regulating ion transport into the scala media.14 A disturbance in ion balance between production and résorption of endolymph has been reported to be the primary cause of endolymphatic hydrops.1S On the other hand, ionic concentrations in the scala tympani and scala media have been found to be significantly altered in experimental hydrops.16 Although biochemical changes in the labyrinthine fluids in otosclerosis may play a role in the development of endolymphatic hy drops, it is still unknown whether these biochemical changes are caused by a direct enzymatic effect of oto sclerosis or by a secondary alteration in the composition of the labyrinthine fluids as a result of otosclerotic ob struction of the vestibular aqueduct. If the biochemical changes were caused by a direct enzymatic effect of the otosclerosis, one would expect that the hydrops would be related to the size and activity of the oto sclerotic foci. We did not observe this in our collection of otosclerotic bones.
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Otosclerotic obstruction of the vestibular aqueduct may cause histopathologic changes of the endolym phatic duct and sac, the vestibular aqueduct, or the periaqueductal area. These histopathologic changes could directly disturb the flow and absorption of en dolymph in the endolymphatic duct and sac or indirectly disturb the drainage of the venous system of the peri aqueductal area, thereby producing the hydrops. Perisaccularfibrosis,17sclerotic changes around the duct,18 narrowing of the lumen in the endolymphatic duct,19 loss of epithelial integrity and atrophy of the sac,20 small vestibular aqueduct,21 and a narrow external aperture of the vestibular aqueduct22 have been observed in Meniere's disease. Abnormal venous drainage via the paravestibular canaliculi has also been suggested as an important mechanism in Meniere's disease.23 We ob served obstructive histopathologic changes, including marked narrowing of the lumen of the endolymphatic duct and sac resulting fromfibrosisin all four temporal bones. Our findings indicate that otosclerotic involve ment of the vestibular aqueduct by obstructive histo pathologic changes can disturb theflowand /or absorp tion of endolymph in the endolymphatic duct and sac, and result in hydrops. Severe endolymphatic hydrops was observed in the cochlea and the vestibule in all four temporal bones in the present study, collapse of the dilated saccule was observed in three of the four bones, and collapse of the ductus reuniens was observed in all of these three. Although cochlear hydrops is described as a common finding in temporal bones with Meniere's disease, stud ies of the disease in human temporal bones have shown various saccular pathologies.24·25 In a study of 19 tem poral bones with Meniere's disease,24 saccular hydrops was observed in all cases. In another study of 22 tem poral bones with Meniere's disease,25 saccular hydrops was observed in 19 cases and saccular collapse in two cases. In animal studies, hydrops in both the cochlea and saccule has commonly been observed after obli teration of the endolymphatic duct and sac,9 but—after obliteration of the ductusreuniens—cochlearhydrops, saccular collapse, and a normal utricle have been found in the majority of cases.10 Although collapsed saccule and ductus reuniens have been observed in human tem poral bones with cochlear hydrops, the mechanism for collapse is still unknown.26 Collapse of the dilated saccule, with severe oto sclerotic foci on the stapedial footplate and otosclerotic foci and/or abnormal basophilic deposits around the ductus reuniens, were observed in both ears of case 1. In therightear of case 2, however, collapse and partial rupture of the dilated saccule were observed without
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otosclerotic involvement in the stapedial footplate or die ductus reuniens. It has been reported that abnormal crystalline deposits in the cochlear duct are associated with abnormal labyrinthine fluid dynamics in otoscler otic hydrops with saccular collapse.6 It is possible that collapse of the dilated saccule is related to an alteration in the composition of the labyrinthine fluids through enzymatic reactions of active otosclerosis—especially involving the stapedial footplate—or to obstruction of the ductus reuniens by otosclerosis and /or basophilic deposits as in case 1, and (as in case 2) is related to rupture of the overexpanded saccule or collapse of the ductus reuniens. In conclusion, otosclerotic involvement of the vestibular aqueduct has been demonstrated to cause a nar rowing of lumen byfibrosisin the endolymphatic duct and sac. This may disturb the outflow and/or absorption of endolymph, probably leading to endolymphatic hy drops, a histologie finding frequently associated with Meniere's disease, a clinical entity these subjects may have had. Our findings support the theory of longitu dinal fluid of endolymph. Further studies of temporal bones in humans are needed to clarify the mechanism by which otosclerosis may involve the vestibular aq ueduct and lead to endolymphatic hydrops. We wish to thank Noriko Morizono for processing of his tologie sections, Sherry Lamey for the photography, and JoAnn Knox for preparation of the manuscript. REFERENCES 1. PaparellaMM. Pathology of Meniere's disease. Ann Otol Rhinol Laryngol 1984;93:31-5. 2. Paparella MM. Pathogenesis of Meniere's disease and Meniere's syndrome. Acta Otolaryngol 1984:10-26. 3. Black FD, Sando I, Hildyard VH, Hemenway WG. Bilateral multiple otosclerotic foci and endolymphatic hydrops: histological case report. Ann Otol-Rhinol Laryngol 1969;78:1062-73. 4. Igarashi M, Jerger S, O-Uchi T, Alford BR. Fluctuating hearing loss and recurrent vertigo in otosclerosis: an audiologic and tem poral bone study. Arch Otorhinolaryngol 1982;236:161-71. 5. Johnsson LG, Hawkins JE Jr, Linthicum FH Jr. Cochlear and vestibular lesions in capsular otosclerosis as seen in microdis section. Ann Otol Rhinol Laryngol 1978;87:1-40. 6. Johnsson LG, Hawkins JE Jr, Fouse RC, et al. Cochlear and otoconial abnormalities in capsular otosclerosis with hydrops. Ann Otol Rhinol Laryngol 1982;91:3-15. 7. Schuknecht HF, Gulya AJ. Endolymphatic hydrops: an overview and classification. Ann Otol Rhinol Laryngol 1983;92:1-20. 8. Liston SL, Paparella MM, Mancini F, Anderson JH. Otosclerosis and endolymphatic hydrops. Laryngoscope 1984;94:1003-7.
9. Kimura RS. Experimental blockage of the endolymphatic duct and sac and its effect on the inner ear of the guinea pig: a study of endolymphatic hydrops. Ann Otol Rhinol Laryngol 1967;76:664-87. 10. Kimura RS, Schuknecht HF, Ota CY, Jones DD. Obliteration of the ductus reuniens. Acta Otolaryngol 1980;89:295-309. 11. Yoo TJ, Stuart JM, Rang AH, Townes AS, Tomoda K, Dixit S. Type II collagen autoimmunity in otosclerosis and Meniere's disease. Science 1982;217:1153-5. 12. Nadol JB Jr, McKenna MS. Histopathology of Meniere's disease and otosclerosis: relevance of possible immune-mediated patho genesis. In: Veldman JE, ed. Immunobiology, histopathology, and tumor immunology in otolaryngology. Proceedings Second International Academic Conference, Utrecht, The Netherlands, August 26-29, 1986. Amsterdam: Kugler Publication, 1987;16584. 13. Chevance LG, Causse J, Bretlau P, Jörgensen MB, Berges J. Hydrolytic activity of the perilymph in otosclerosis; a preliminary report. Acta Otolaryngol 1972;74:23-8. 14. Ross MD, Ernst SA, Kerr TP. Possible functional roles of Na + , K+-ATPase in the inner ear and their relevance to Meniere's disease. J Otolaryngol 1982;3:353-60. 15. Vosteen KH, Morgenstern. Biochemical aspects of inner pathophysiology. In: Pfaltz CR, ed. Controversial aspects of Meniere's disease. New York: New York Thieme, Inc., 1986:16-28. 16. Cohen J, Morizono T. Changes in EP and inner ear ionic con centrations in experimental endolymphatic hydrops. Acta Oto laryngol 1984;98:398-402. 17. Zechner G, Altmann F. Histological studies on the human en dolymphatic duct and sac. Pract Oto-rhino-laryngol 1969;3l: 65-83. 18. Sakai N, Igarashi M, Ohashi K, Ishii M. Sclerotic changes around the endolymphatic sac in human temporal bones. Arch Otolaryngol 1985;242:315-20. 19. Ikeda M, Sando I. Endolymphatic duct and sac in patients with Meniere's disease: a temporal bone histopathological study. Ann Otol Rhinol Laryngol 1984;93:540-6. 20. Arenberg IK, Marovitz WF, Shambough GI Jr. The rale of the endolymphatic sac in the pathogenesis of the endolymphatic hy drops in man. Acta Otolaryngol 1970;76:1-49. 21. Sando I, Ikeda M. The vestibular aqueduct in patients with Me niere's disease: a temporal bone histopathological study. Acta Otolaryngol 1984;97:558-70. 22. Stahle J, Wibrand HF. The temporal bone in patients with Me niere's disease. Acta Otolaryngol 1983;95:81-94. 23. Güssen R. Vascular mechanism in Meniere's disease. Acta Oto laryngol 1982;108:544-9. 24. Antoli-Candela F. The histopathology of Meniere's disease. Acta Otolaryngol 1976;82:5-42. 25. Okuno T, Sando I. Localization, frequency, and severity of en dolymphatic hydrops and the pathology of the labyrinthine mem brane in Meniere's disease. Ann Otol Rhinol Laryngol 1987: 438-45. 26. Kitamura KK, Schuknecht HF, Kimura RS. Cochlear hydrops in association with collapsed saccule and ductus reuniens. Ann Otol Rhinol Laryngol 1982;91:5-13.
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