Delayed endolymphatic hydrops: Study and review of clinical implications and surgical treatment.

Abstract

Delayed endolymphatic hydrops (DEH) differs from Meniere's disease in that it occurs in pre-existing ear pathology in patients who have a profound unilateral or total deafness that was caused by infection, trauma, or unknown causes during childhood or adulthood. We performed a retrospective review of 160 patients with ipsilateral, contralateral, or bilateral DEH. Eighty-seven patients who did not respond to medical therapy underwent surgical treatment. Our findings indicate that the more conservative surgical procedures--endolymphatic sac surgery, cochleosacculotomy, and streptomycin perfusion--are all as effective as and less destructive than labyrinthectomy for controlling vertigo. The clinical results of this study would seem to support the observations of others that DEH and Meniere's disease are related disorders caused predominantly by cases of viral labyrinthitis with unknown etiology.

Introduction

Delayed endolymphatic hydrops (DEH) was first reported in 1975 in papers by both Nadol et al [1] and Wolfson and Leiberman. [2] The condition was named and further elaborated on by Schuknecht, who classified DEH as either ipsilateral, contralateral, or bilateral. [3] Ipsilateral DEH is characterized by the early onset of a profound or total hearing loss in one ear in conjunction with Meniere's-type vertigo. Ipsilateral DEH is often accompanied by nausea and vomiting. It is occasionally associated with tinnitus, pressure, or fullness in the same ear after a period of years has elapsed. In the contralateral expression, the patient experiences a fluctuating and progressive hearing loss--with or without Meniere's-type episodic vertigo--in the ear opposite the one that earlier experienced the hearing loss. Patients with bilateral DEH experience hearing loss in both ears some years before the onset of symptomatic endolymphatic hydrops.

The most common causes of DEH are inflammation, trauma, and unknown events during childhood. Schuknecht et al made a histopathologic analysis of the temporal bones of two patients with contralateral DEH. [4] They reported that the pathologic changes in the deaf ears were consistent with viral labyrinthitis, whereas the changes in the hearing ears were similar to those seen in Meniere's disease.

The first-line treatment is medical therapy. If DEH proves to be refractory to this, surgery is indicated. The type of surgical procedure depends on whether the patient has ipsilateral or contralateral DEH. For patients with ipsilateral DEH, labyrinthectomy has proved to be curative. For contralateral DEH, Schuknecht reported in 1978 that there was no satisfactory surgical treatment. [3] Since then, however, Hicks and Wright reported that endolymphatic sac (ELS) surgery in patients with contralateral hydrops is relatively safe, provides an excellent chance of eliminating or controlling vertigo and maintaining or improving hearing, and carries a low risk of surgical anacusis. [5] They consider ELS surgery to be the only option when symptoms of contralateral DEH are debilitating and refractory to medical treatment.

In this article, we describe our retrospective review of 160 patients with DEH. We discuss the clinical implications of medical treatment and evaluate the surgical options for those patients whose symptoms do not respond to medical therapy. We introduce alternate surgical modalities for ipsilateral DEH, and we emphasize the need for caution in the surgical treatment of contralateral and bilateral DEH.

Patients and methods

Between 1979 and late 1998, 160 cases of DEH in 161 ears were diagnosed at Chang Gung Memorial Hospital in Taipei. Of these, 105 were ipsilateral, and 54 were contralateral, and one was bilateral. Just less than half of these patients responded to conservative treatment with a combination of a vasodilator, labyrinthine sedative, diuretic, low-salt diet, and psychological support. In 87 patients (54%), symptoms were refractory to medical therapy, and they required surgical treatment. (In another case that is not included in this series, a patient whose symptoms mimicked delayed hydrops was found during surgery to have an intravestibular lipoma. [6])

As is the procedure for assessing other patients with dizziness and vertigo, the evaluation of these 160 patients included (1) a careful history, (2) an otolaryngologic examination, (3) a blood workup, (4) an audiometric profile, (5) electronystagmography (ENG) with caloric testing, (6) radiologic studies, and (7) a dehydration test if necessary.

ENG with caloric testing showed that cochlear function was generally not parallel to vestibular function, particularly in the contralateral cases. Not all of the deafened ears showed a reduced vestibular response, and the better-hearing ears did not always show a normal vestibular response.

Ipsilateral and bilateral DEH. Among the 105 patients with ipsilateral DEH, the presumed causes of hearing loss were otitis media and mastoiditis in 21 cases, sudden deafness in 12, mumps and viral labyrinthitis in 10, head injury in 10, high fever in three, acoustic trauma in three, drug intoxication in two, and anaphylactic shock in one case (table 1). There were also 35 cases caused by an unknown etiology during childhood and eight cases of unknown cause during adulthood. At their initial visit, these patients' ages ranged from 16 to 72 years (mean: 41). Their ages at the onset of hearing loss ranged from 2 to 50 years (mean: 15), and their ages at the onset of vertigo ranged from 9 to 71 years (mean: 33). The length of the delay between the onset of deafness and the onset of vertigo ranged from 2 to 53 years (mean: 22). All patients with ipsilateral DEH had normal or satisfactory hearing in the opposite ear.

Surgery was necessary for 67 patients, including the one with bilateral DEH. An initial transmastoid labyrinthectomy was performed on 56 patients, ELS surgery on six, and cochleosacculotomy on five. Three patients who had failed initial ELS surgery later underwent a labyrinthectomy.

Contralateral DEH. In the 54 patients with contralateral DEH, the presumed causes of hearing loss were upper respiratory tract infection with high fever in seven, otitis media and mastoiditis in five, mumps in five, head injury in five, sudden deafness in four, measles in two, acoustic trauma (by firecrackers) in one, and meningitis in one (table 2). There were 18 unknown causes that occurred during childhood and six during adulthood. At the initial visit, patients' ages ranged from 20 to 65 years (mean: 46). Their ages at the onset of hearing loss ranged from 4 to 50 years (mean: 14), and their ages at the onset of inner ear symptoms ranged from 15 to 75 years (mean: 41). The length of delay between the onset of deafness and the onset of vertigo ranged from 5 to 66 years (mean: 28).

Surgery was required for 16 of these patients. All of them had a fluctuating hearing loss in addition to their vertigo, as evidenced by a positive glycerol test as documented by serial audiography.

Results

Ipsilateral and bilateral DEH. Among the 56 patients who underwent an initial or revision transmastoid labyrinthectomy, symptoms were completely controlled in 49 (88%), including the three of the six (seven ears) who had failed ELS surgery (see case report 1) (table 3). The other seven patients experienced a relief of vertigo but not dizziness; their dizziness was brought under control with medical therapy. The patient with bilateral DEH continued to experience dizziness, which was controlled by medication (see case report 2).

A complete relief of symptoms was achieved in four of the five patients who underwent a cochleosacculotomy. The remaining patient was subsequently and successfully treated with vestibular streptomycin perfusion (see case report 3).

Including the bilateral case, a total of 68 surgical procedures were performed for ipsilateral DEH.

Contralateral DEH. All 16 patients with contralateral DEH whose vertigo was refractory to medical therapy underwent ELS surgery with various draining methods. In the seven most recent cases, the endolymphatic sac was drained and its lumen expanded by insertion of a fan-folded Silastic sheet (endolymphatic sac balloon surgery). In four patients, a device with a capillary tube (Arenberg's inner ear valve or Austin's endolymph dispersement drain) was inserted into the endolymphatic duct. Four other patients had their endolymphatic sac drained by a simple incision, and one patient underwent decompression alone.

Thirteen of the 16 patients (81%) experienced a complete resolution of vertigo following ELS surgery, while the remaining three experienced substantial control; these latter three patients reported dizziness, which was controlled medically (table 4). Hearing levels were maintained in 14 patients, improved in one (see case report 4), and worse in one (see case report 5).

Case reports

Five selected case reports follow, describing two patients with ipsilateral DEH, the one with bilateral DEH, and two with contralateral DEH.

Case I (ipsilateral). A 19-year-old woman reported a severe sensorineural hearing loss in the left ear that began during her childhood following an episode of otitis media and mastoiditis. During the previous year, she had experienced episodic vertigo and tinnitus in the left ear.

Her physical examination revealed an atrophic scarring of the left tympanic membrane. Audiography showed residual responses at 0.25 and 0.5 kHz in the left ear and normal hearing in the right. ENG revealed a canal paresis in the left ear and a normal response on the right. Blood test results were unremarkable, but a mastoid x-ray showed sclerosis on the left. In 1979, ELS surgery was performed on the left ear, but it failed to control her vertigo. Three months later, when her vertigo had become incapacitating, a labyrinthectomy was reluctantly performed to relieve her symptoms.

Case 2 (bilateral). A 29-year-old woman had had a profound sensorineural hearing loss in both ears since the age of 4 years following an episode of high fever. During the previous year, she began to experience episodic vertigo and tinnitus and fullness in both ears.

A physical examination revealed that her eardrums were normal. Audiography confirmed a profound bilateral sensorineural hearing loss of 85 dB pure-tone average (PTA) in both ears, a 12% speech discrimination score (SDS) in the right ear, and an 8% SDS in the left. ENG revealed a reduced vestibular response in both ears. Blood test results were unremarkable, and dehydration testing was negative bilaterally. Radiologic study of the mastoids was also unremarkable.

Because the woman's vertigo was disabling, ELS surgery was performed on the right ear with an Austin endolymph dispersement drain in 1987. One month later, the same procedure was employed on the left ear. Afterward, the woman reported no recurrence of her vertigo attacks. She did occasionally experience adjunctive spells, which were controlled medically. She has aidable hearing.

Case 3 (ipsilateral). In 1987, a 26-year-old woman had suddenly experienced a nearly total deafness on the left side, which was accompanied by tinnitus and fullness in the same ear. Left ear audiometry revealed only residual responses at 1 and 2 kHz. No improvement was noted after medical treatment.

Two years later, the patient complained of episodic vertigo, nausea, and vomiting. ENG showed a normal vestibular function bilaterally. Audiography confirmed the total deafness on the left (10 dB PTA), a speech reception threshold of 10 dB, and a 100% SDS on the right side.

When 4 months of medical treatment proved to be ineffective, a cochleosacculotomy was performed on the left ear. The patient reported no further vertigo attacks postoperatively, but she did complain of dizziness and disabling disequilibrium. Streptomycin perfusion (0.1 ml of 25 [micro]g/ml streptomycin compound) of the labyrinth was initiated 7 months later. Postoperatively, the patient's fistula test was negative, and she exhibited no response to the maximal (icewater) caloric test. The patient continues to be asymptomatic.

Case 4 (contralateral). In 1983, a 40-year-old woman came to our institution with a profound sensorineural hearing loss in the left ear, which she had had since the age of 10 years following an attack of bacterial meningitis. The patient said that she was now experiencing a fluctuating hearing loss in the right ear, which was accompanied by tinnitus. The results of her otolaryngologic and physical examinations were unremarkable. Audiography revealed a profound sensorineural hearing loss in the left ear of 90 dB PTA and a low-frequency hearing loss in the right ear of 40 dB PTA with a 4-kHz dip. Tone-decay tests were negative on both sides. ENG with caloric testing produced a reduced vestibular response in the left ear and a normal response in the right. Computed tomography (CT) revealed hydrocephalus. The patient's glycerol test was positive in the right ear. The woman was diagnosed as having contralateral DEH associated with hydrocephalus, and medical treatment was prescribed.

Two years later, she returned complaining of serious disequilibrium, a transient floating sensation, and noise intolerance in the right ear. ENG again revealed a normal response in the right ear. Repeat audiography showed 95 dB PTA and a 0% SDS in the left ear and 40 dB PTA and 36% SDS in the right. High-resolution CT and pneumocisternography were both negative, indicating that there were no tumors in the cerebellopontine angle and internal auditory canals. A repeat glycerol test was again positive on the right. The patient's symptoms were controlled by medical therapy.

Five years later in 1990, the patient began to experience severe vertigo, nausea, and vomiting. Her hearing had deteriorated in the right ear and her disequilibrium had intensified. Her Romberg's test was positive. All other test results were similar to those previously conducted. The woman's disequilibrium and headaches had become so severe (which indicated recurrent hydrocephalus) that a ventriculoperitoneal shunt was reluctantly inserted. The shunt was successful in relieving her symptoms. One week after surgery, her vertigo gradually diminished and her hearing threshold in the right ear had improved from 55 to 40 dB PTA. One month postoperatively, the patient was discharged from the hospital.

Three days after discharge, the patient returned to the emergency room complaining of hemiparesis and severe headache on the right. CT revealed the presence of a subdural hemorrhage. A craniotomy was performed and a ventriculoperitoneal shunt revision was successfully performed. The patient recovered, and conservative measures eventually stabilized the cochleovestbular symptoms. To date, she remains asymptomatic.

Cases of concomitant DEH and hydrocephalus are undoubtedly caused by meningitis. However, the relationship between the symptoms of DEH and hydrocephalus has not yet been satisfactorily explained.

Case 5 (contralateral). A 42-year-old woman had been completely deaf in her left ear since the age of 8 years. The cause of her deafness was unknown. During the previous year, she began experiencing episodic vertigo, tinnitus, and fullness in her right ear.

Her tympanic membranes were normal, and the rest of her physical examination was unremarkable. A preoperative audiogram showed 25 dB PTA and a 100% SDS in the right ear and confirmed her total deafness in the left. Her blood test results were unremarkable, and her mastoid x-ray was normal on both sides. A glycerol test was positive on the right side. Because her vertigo had become incapacitating, ELS surgery was performed on the right ear with an Arenberg's inner ear valve in 1984. Following surgery, the patient's hearing increased by 10 dB PTA, and to date her vertigo is still completely resolved.

Discussion

Symptomatology. Schuknecht and Gulya described endolymphatic hydrops in terms of its symptomatic and asymptomatic forms. [7] DEH can be considered an asymptomatic, clinically silent type because a unilateral deafness caused by an earlier otologic insult can exist for years before it becomes symptomatic. Meanwhile, Meniere's disease is defined as the idiopathic, symptomatic form of endolymphatic hydrops of unknown cause because symptoms develop in one or both ears that had previously had normal auditory and vestibular functions. This acquired form of endolymphatic hydrops or Meniere's syndrome includes cases in which a documented insult has been caused by either inflammation or trauma to a previously normal labyrinth.

Ipsilateral DEH is characterized by symptoms that mimic those of Meniere's-type vertigo. These symptoms occur after a lapse of several to many years following the onset of deafness in that ear. [1,2] Symptoms of contralateral DEH, in which a Meniere's symptom complex develops in the ear opposite the deaf ear, typically include progressive and fluctuating hearing loss, aural pressure and tinnitus, and/or episodic attacks of vertigo accompanied by nausea and vomiting. In bilateral DEH, a profound hearing loss in both ears precedes the onset of symptoms.

It has been proposed that DEH is a pathologic condition that is the final common manifestation of a variety of otologic insults, including infection (either viral or bacterial), trauma (either physical or acoustic), the onset of sudden deafness, and other causes known and unknown. [7] Schuknecht suggested that in DEH, the reabsorption of endolymph is compromised as a result of two possible consequences of the original insult: either damage to the endolymphatic sac or blockage of the vestibular aqueduct. [3] If so, this implies that some auditory and/or vestibular function remains because some secretory tissue is still present, although many patients eventually develop cochleovestibular symptoms.

Schuknecht and Gulya later described two unique temporal bone histopathologic studies in two patients with contralateral DEH. [7] They found that the histopathology in the deafened ear was typical of viral labyrinthitis (based on its similarity to the histopathology of ears deafened by mumps or measles) and that pathologic changes in the opposite ear were similar to those seen in Meniere's disease. [8] Supplementing their findings with those of Koga et al [9] and Westmore et al, [10] who suggested that unilateral hearing loss in childhood is often caused by subclinical mumps, Schuknecht et al [4] proposed that patients with contralateral DEH probably experienced a viral attack in the hearing ear at the same time the opposite ear was deafened.

Schuknecht et al also reported that a subclinical viral labyrinthitis during infancy might be a common cause of both contralateral DEH and Meniere's disease. [4] Support for this suggestion is provided by evidence that some bilateral loss of vestibular function occurs in contralateral cases. Moreover, a subclinical attack in the deafened ear in conjunction with the precipitating cause of hearing loss often results in hydrops in the ipsilateral ear. Caloric test results in the 160 patients in this series resulted in similar findings (tables 5 and 6).

Furthermore, in another series of 159 patients who had a total or profound unilateral hearing loss for a period of years, we found that 14 (8.8%) had DEH-seven contralateral, six ipsilateral, and one bilateral. Of the 145 patients who had no DEH symptoms and whose cause of unilateral deafness was unknown, 17 were randomly chosen to undergo caloric ENG in both ears, in addition to routine audiometric and radiologic studies. It is interesting that three of these patients exhibited a reduced yestibular response in the normal-hearing ear and one had no response. Conversely, not all of the deafened ears evidenced a compromised vestibular function; there were five normal caloric responses, indicating that there was a simultaneous vestibular insult in both the deafened ear and the hearing ear.

The eventual development of DEH symptoms in asymptomatic ears appears to be inevitable. Indeed, in a study that spanned 14 years, Kamei found that 27 of 89 juveniles (30%) who had a total unilateral deafness eventually developed episodic vertigo; three also complained of fluctuating hearing in the previously normal contralateral ear. [11] In addition, Schuknecht et al reported that 42 of 62 patients with profound unilateral deafness (68%) had experienced deafness of unknown etiology during childhood. [4]

Our findings appear to be relevant to the propositions expressed by Schuknecht and Gulya that (1) DEH and Meniere's disease are related, (2) that they are caused primarily by a viral labyrinthitis in patients who have deafness of unknown etiology, and (3) that DEN is a pathologic condition that is the final common manifestation of a variety of otologic insults. [7]

Surgical treatment. When medical therapy fails in the treatment of ipsilateral DEH, labyrinthectomy is curative of debilitating vertigo. In our series, labyrinthectomy eliminated vertigo in all 56 patients who underwent the procedure (table 3). Seven of these patients, most of whom were elderly, continued to experience dizziness; this would be expected because the central compensation mechanisms in older patients are often compromised.

ELS surgery has been recommended by Hicks and Wright [5] and by Pulec. [12] It is a more conservative option than labyrinthectomy for controlling vertigo, although it is not always as successful. [12-21] In our series, ELS surgery was performed on six patients (seven ears), and vertigo was eliminated in three patients.

Two other surgical modalities--cochleosacculotomy and streptomycin perfusion of the labyrinth--were used in our series, and they were also effective. Cochleosacculotomy was successful in four of five patients; the one patient who failed was subsequently and successfully treated with streptomycin perfusion. When streptomycin is delivered systemically at the appropriate dosage, it can selectively destroy the vestibular labyrinth while sparing cochlear function. [22] Similarly, local aminoglycoside antibiotics applied adjacent to the inner ear can also selectively destroy the vestibular stereocilia and sensory cells while leaving the first-order neurons intact and causing only minimal damage to the cochlea. [23-26]

The slow injection of 0.1 ml of artificial perilymph, containing 25 [micro]g/ml of streptomycin, into the perilymphatic space of the lateral semicircular canal is called Shea's technique. [26] This procedure is performed with a 30-gauge needle in an attempt to destroy the vestibular receptors. [27] In theory, the perilymphatic trabecular meshwork and the membrana limitans should prevent, or at least minimize, the spread of streptomycin into the cochlea, thus preventing adverse effects to cochlear function. Since 1986, Shea has performed 166 streptomycin perfusions, and vertigo was controlled in all cases. [26]

In our series, the three patients who received streptomycin perfusion (two primary and one revision) experienced a complete resolution of their vertigo In each case, the operated ear showed no response to the maximal caloric test postoperatively, confirming that vestibular function had been destroyed. This suggests that in order to relieve symptoms in patients with ipsilateral DEH, more conservative measures such as ELS surgery, cochleosacculotomy, [27] and streptomycin perfusion can be chosen arbitrarily as either primary or subsequent procedures as an alternative to labyrinthectomy. Studies show that these more conservative procedures are equally efficacious in terms of alleviating vertigo (even among elderly patients) and in preserving the inner ear structure. [28]

Preserving the inner ear structure might become increasingly important, even in a deafened ear, now that cochlear implantation has become a standard procedure for patients with total or profound bilateral hearing loss. However, we do not recommend streptomycin perfusion for patients with contralateral or bilateral DEH, in whom hearing preservation is extremely important. In our experience, attempts to titrate streptomycin compound doses can be problematical because some of the compound is often regurgitated on administration. It is also very likely that titration is made difficult by differences in individual patients' inner ear pathology, which might reduce the effect of the trabecular meshwork and membrana limitans. Therefore, predicting the amount of streptomycin, the injection pressure, and the injection speed necessary to avoid damage to the cochlea is difficult.

In patients with contralateral DEN or Meniere's disease who still have significant hearing, preservation of hearing during surgery on the only-hearing or better-hearing ear is of the utmost importance. Therefore, only the safest techniques should be attempted. In 1978, Schuknecht wrote that there was no satisfactory therapy available for contralateral DEH. [3] In 1983, Morrison reported on ELS surgery on the only-hearing or better-hearing ear in patients with contralateral DEH and concluded that because the risk of surgical anacusis was only 1% with ELS surgery, it should be the only option for these patients. [28] In 1988, Hicks and Wright argued that only ELS surgery should be performed to alleviate disabling vertigo in contralateral DEH. [5] We agree. In our study, ELS cured vertigo in 13 of the 16 patients on whom it was performed (table 4). The other three patients continued to experience dizziness, which was controlled medically. Hearing was preserved in all but one patient. One patient experienced an improvement of 10 dB.

Among patients with intractable Meniere's disease, the success rate of ELS surgery has been reported to range from approximately 70 to 95% for relieving vertigo and approximately 60 to 90% for improving and sustaining hearing. [12-25,21,29] Meanwhile, the incidence of surgical anacusis is less than 2%. In this context, it is worth noting that the incidence of anacusis following ELS surgery is marginally higher when endolymph is drained from the duct than from the sac. [15] Although there was no cochlear function damage observed in our series, it appears that endolymphatic duct procedures with intraductal capillary devices are best avoided--or at least performed cautiously--in patients with contralateral DEH in order to avoid adverse or catastrophic effects on inner ear function. It is interesting to note that promising results have been achieved with a drainage method (endolymphatic sac balloon surgery) devised by the primary author (T.S.H.). [30] This technique involves opening the endolymphatic sac and exp anding its lumen by inserting a Silastic ribbon sheet that is fan-folded within the sac.

The chances of achieving long-term vertigo control are greater with vestibular nerve section than with ELS surgery. [29,3] However, vestibular nerve section is difficult to perform and carries a higher risk of compromising inner ear function ([greater than]10% anacusis) and morbidity. (Even so, Silverstein et al reported that none of their cases suffered total hearing loss. [32]) Therefore, ELS surgery remains the procedure of choice in the only-hearing or better-hearing ear in patients with contralateral DEH.

If symptoms recur, revision sac surgery can be as effective as primary ELS surgery. Paparella and Sajjadi [33] reported that revision sac surgery not only eliminated vertigo, it greatly improved hearing in some cases, a finding that paralleled our own. [34] Paparella and Sajjadi also noted that the effectiveness of this revision procedure was similar to that of the primary operation.

A newer procedure was recently developed that involves the use of the Round Window micro-Cath (IntraEar Corp.; Cupertino, Calif.). This perfusion device is equipped with a micropump that provides a continuous delivery of minute, controllable amounts of gentamicin. Absorption is maximized by allowing the gentamicin to permeate through the round window membrane and into the inner ear. This technique provides adequate gentamicin toxicity to the vestibular receptor while sparing cochlear function. Our experience with this procedure in controlling vertigo while preserving hearing have been very positive.

From the Department of Otolaryngology, Chang Gung Medical College, Chang Gung University, Taipei, Taiwan.

Reprint requests: Tsun-Sheng Huang, MD, Department of Otolaryngology, Chang Gung Memorial Hospital, 199 Tun-Hwa North Rd., Taipei, Taiwan 105. Phone: [phone]; fax: [phone]; e-mail: [e-mail]

References

(1.) Nadol JB Jr., Weiss AD, Parker SW, Vertigo of delayed onset after sudden deafness. Ann Otol Rhinol Laryngol 1975;84:841-6.

(2.) Wolfson RJ, Leiberman A. Unilateral deafness with subsequent vertigo. Laryngoscope 1975;85:1762-6.

(3.) Schuknecht HF. Delayed endolymphatic hydrops. Ann Otol Rhinol Laryngol 1978;57:743-8.

(4.) Schuknecht HF, Suzuka Y, Zimmermann C. Delayed endolymphatic hydrops and its relationship to Meniere's disease. Ann Otol Rhinol Laryngol 1990;99:843-53.

(5.) Hicks GW, Wright JW III. Delayed endolymphatic hydrops: A review of 15 cases. Laryngoscope 1988;98:840-5.

(6.) Huang TS. Primary intravestibular lipoma. Ann Otol Rhinol Laryngol 1989;98:393-5.

(7.) Schuknecht HF, Gulya AJ. Endolymphatic hydrops. An overview and classification. Ann Otol Rhinol Laryngol Suppl 1983;106:1-20.

(8.) Lindsay JR, Davey PR, Ward PH. Inner ear pathology in deafness due to mumps. Ann Otol 1960;69:918-35.

(9.) Koga K, Kawashiro N, Nakayama T, Makino S. Immunological study on association between mumps and infantile unilateral deafness. Acta Otolaryngol Suppl 1988;456:55-60.

(10.) Westmore GA, Pickard BH, Stern H. Isolation of mumps virus from the inner ear after sudden deafness. Br Med J 1979;1:14-5.

(11.) Kamei T. Delayed vertigo. In: Hood JD, ed. Vestibular Mechanisms in Health and Disease. VI Extraordinary Meeting of the Barany Society. London; New York: Academic Press, 1978: 369-74.

(12.) Pulec JL. Endolymphatic subarachnoid shunt for Meniere's disease in the only hearing ear. Laryngoscope 1981;41:771-83.

(13.) Kitahara M, Kitajima K, Yazawa Y, Uchida K. Endolymphatic sac surgery for Meniere's disease: Eighteen years' experience with the Kitahara sac operation. Am J Otol 1987;8:283-6.

(14.) Huang TS. Valve implants compared to other surgical methods. Am J Otol 1987;8:301-6.

(15.) Arenberg IK. Results of endolymphatic sac to mastoid shunt surgery for Meniere's disease refractory to medical therapy. Am J Otol 1987;8:335-44.

(16.) Plester D. Surgery of Meniere's disease. In: Pfaltz CR, ed. Controversial Aspects of Meniere's Disease. New York: Thieme Medical Publishers, 1986:104-12.

(17.) Austin DF. Endolymphatic fistulization, Ann Otol Rhinol Laryngol 1984:93:534-9.

(18.) Huang TS, Lin CC. Austin endolymph dispersement shunt surgery for Meniere's disease. Acta Otolaryngol Suppl 1989;468:99-103.

(19.) Arenberg IK, Zoller SA, Van de Water SM. The results of the first 300 consecutive endolymphatic system-mastoid shunts with valve implants for hydrops. Otolaryngol Clin North Am 1983:16:153-74.

(20.) Morrison AW. The surgery of vertigo: Saccus drainage for idiopathic endolymphatic hydrops. S Laryngol Otol 1976;90:87-93.

(21.) Pulec JL. Permanent restoration of hearing and vestibular function by the endolymphatic subarachnoid shunt operation. Ear Nose Throat J 1995;74:544-6, 548, 550.

(22.) Takumida M, Bagger-Sjoback D, Harada Y, et al. Sensory hair fusion and glycocalyx changes following gentamicin exposure in the guinea pig vestibular organs. Acta Otolaryngol 1989;107:39-47.

(23.) Meza G, Lopez I, Paredes MA, et al. Cellular target of streptomycia in the internal ear. Acta Otolaryngol 1989;107:406-11.

(24.) Norris CR, Amedee RG, Risey JA, Shea JJ. Selective chemical vescibulectomy. Am J Otol 1990;11:395-400.

(25.) Kimura RS, Iverson NA, Southard RE. Selective lesions of the vestibular labyrinth. Ann Otol Rhinol Laryngol 1988;97:577-84.

(26.) Shea JJ, Norris CR. Streptomycin perfusion of the labyrinth. Acta Otolaryngol Suppl 1991;485:123-30.

(27.) Huang TS, Lin CC. Cochleosacculotomy for Meniere's disease. Adv Otorhinolaryngol 1988;42:275-9.

(28.) Morrison AW. Sac surgery on the only or better hearing ear. Otolaryngol Clin North Am 1983;16:143-51.

(29.) Pulec JL. Surgical treatment of vertigo. Acta Otolaryngol Suppl 1995;519:21-5.

(30.) Huang TS, Lin CC. Endolymphatic sac ballooning surgery for Meniere's disease. Ann Otol Rhinol Laryngol 1994;103:389-94.

(31.) Palva T, Ylikoski S, Paavolainen M, et al. Vestibular neurectomy and saccus decompression surgery in Meniere's disease. Acta Otolaryngol 1979;88:74-8.

(32.) Silverstein H, Norrell H, Haberkamp T. A comparison of retrosigmoid IAC, retrolabyrinthine, and middle fossa vestibular neurectomy for treatment of vertigo. Laryngoscope 1987:97:165-73.

(33.) Paparella MM, Sajiadi H. Endolymphatic sac revision for recurrent Meniere's disease. Am J Otol 1988;9:441-7.

(34.) Huang TS, Lin CC. Revision endolymphatic sac surgery for recurrent Meniere's disease. Acta Otolaryngol Suppl 1991; 485:131-44.

Table 1. Age of symptom onset and time delay according to etiology
in 105 patients with ipsilateral DEH
                               Mean age when     Mean age at
                    n    %     deafened (yr)  first vertigo (yr)
Otitis media        21  20.0       19.9              43.9
and mastoiditis
Sudden deafness     12  11.4       34.9              42.2
Mumps and viral     10   9.5       10.1              30.8
labyrinthitis
Head injury         10   9.5       13.0              31.6
High fever           3   2.9        4.7              25.0
Acoustic trauma      3   2.9       37.7              45.3
Drug intoxication    2   1.9       19.0              48.0
Anaphylactic shock   1   0.9       20.0              29.0
Cause unknown       35   33.3       4.0              21.8
(childhood)
Cause unknown        8   7.6       25.6              34.2
(adulthood)
Mean                               15.2              32.6
Range                             2 to 50          9 to 71
                    Mean time
                    delay (yr)
Otitis media           27.8
and mastoiditis
Sudden deafness         7.3
Mumps and viral        20.7
labyrinthitis
Head injury            18.6
High fever             20.3
Acoustic trauma         7.6
Drug intoxication      29.0
Anaphylactic shock      9.0
Cause unknown          27.8
(childhood)
Cause unknown           8.6
(adulthood)
Mean                   21.5
Range                2 to 53
Age at symptom onset and time delay according to etiology in 54 patients
with cntralateral DEH
                            Mean age when     Mean age at
                   n   %    deafened (yr)  first vertigo (yr)
High fever         7  13.0       4.7              25.0
Otitis media       5   9.3       6.4              34.2
 and mastoiditis
Mumps              5   9.3       5.2              36.6
Head injury        5   9.3      22.0              53.8
Sudden deafness    4   7.4      30.0              42.5
Measles            2   3.7       6.0              23.0
Acoustic trauma    1   1.9      45.0              53.0
Meningitis         1   1.9      10.0              38.0
Cause unknown     18  33.3       4.7              42.0
 (childhood)
Cause unknown      6  11.1      42.8              60.2
 (adulthood)
Mean                            13.5              41.2
Range                          4 to 50          15 to 75
                  Mean time
                  delay (yr)
High fever           20.3
Otitis media         27.8
 and mastoiditis
Mumps                31.4
Head injury          31.8
Sudden deafness      12.5
Measles              17.0
Acoustic trauma       8.0
Meningitis           28.0
Cause unknown        37.3
 (childhood)
Cause unknown        17.4
 (adulthood)
Mean                 27.6
Range              5 to 66
Table 3. Surgical outcomes in 69 patients with ipsilateral DEH
Treatment                  No. patients        Results
Labyrinthectomy                56*         49 asymptomatic
                                            7 remained dizzy+
Endolymphatic sac surgery       6           3 asymptomatic
                                            3 remained dizzy ss
Cochleosacculotomy              5           4 asymptomatic
                                            1 remained dizzy
Streptomycin perfusion          2           2 asymptomatic
Treatment                  Subsequent surgery
Labyrinthectomy
Endolymphatic sac surgery
                           1 labyrinthectomy
Cochleosacculotomy
                           1 streptomycin perfusion
Streptomycin perfusion
(*)53 initial procedures and three revision procedures: inclueds one
patient in the letter group with bilateral DEH.
(+)Controlled medically.
(ss)Includes the patient with bilateral DEH, whose dizziness was
controlled medically.
Table 4. Outcomes of ELS surgery in 16 patients with contralateral DEH
                       n (%)
Vertigo
 Complete control     13 (81)
 Substantial control   3 (19)
Hearing
 Improved              1 (6%)
 Unchanged            14 (88%)
 Worse                 1 (6%)
Table 5. Responses to caloric testing in the 105 ipsilateral cases
                                  Normal  Normal  Reduced*  Reduced
                                   DE+    HE ss     DE        HE
Mastoiditis                         6       12       9         0
Sudden deafness                     5       9        4         0
Mumps and viral                     5       9        4         0
 labyrinthitis
Head Injury                         2       6        4         0
High fever                          1       2        2         0
Acoustic trauma                     1       2        2         1
Drug intoxication                   0       0        2         2
Anaphylactic shock                  1       1        0         0
Cause unknown                       9       20      22         1
(childhood)
Cause unknown                       2       4        4         0
 (adulthood)
Total                               32      65      53         4
                                  None  None  Not performed
                                   DE    HE        DE
Mastoiditis                        0     3          6
Sudden deafness                    2     2          1
Mumps and viral                    1     1          0
 labyrinthitis
Head Injury                        1     1          3
High fever                         0     1          0
Acoustic trauma                    0     0          0
Drug intoxication                  0     0          0
Anaphylactic shock                 0     0          0
Cause unknown                      1     8          3
(childhood)
Cause unknown                      1     3          1
 (adulthood)
Total                              6     19        14
                                  Nor performed
                                       HE
Mastoiditis                             6
Sudden deafness                         1
Mumps and viral                         0
 labyrinthitis
Head Injury                             3
High fever                              0
Acoustic trauma                         0
Drug intoxication                       0
Anaphylactic shock                      0
Cause unknown                           6
(childhood)
Cause unknown                           1
 (adulthood)
Total                                  17
(*) Reduced vestibular response.
(+) Deafened ear.
(ss) Hearing ear.
Table 6. Responses to caloric testing in the 54 contralateral cases
                           Normal          Reduced*       None
                             DE+    HE ss     DE      HE   DE    HE
Mastoiditis                   4       2        0       2    0    0
Sudden deafness               0       2        2       1    1    0
Mumps                         2       5        3       0    0    0
Head injury                   1       2        4       3    0    0
High fever                    4       6        2       1    1    0
Acoustic trauma               1       1        0       0    0    0
Measles                       0       0        2       1    0    1
Meningitis                    0       1        1       0    0    0
Cause unknown (childhood)     8       8        8      10    2    0
Cause unknown (adulthood)     1       2        3       2    1    1
Total                        21      29       25      20    5    2
                           Not performed
                                 DE        HE
Mastoiditis                      1         1
Sudden deafness                  1         1
Mumps                            0         0
Head injury                      0         0
High fever                       0         0
Acoustic trauma                  0         0
Measles                          0         0
Meningitis                       0         0
Cause unknown (childhood)        0         0
Cause unknown (adulthood)        1         1
Total                            3         3
(*)Reduced vestibular response.
(+)Deafened ear.
(ss)Hearing ear.