Endolymphatic Shunt Operation Research Articles

Indications for operative therapy of vestibular vertigo and the associated success rates

The indications for surgical treatment of labyrinthine vertigo associated with severe impairment and a lack of response to medication are heterogeneous. Due to different therapeutic goals and success parameters, the results of treatments can only be compared to a limited extent. This overview of the current literature and procedures performed by the author contains recommendations for indications and outlines the risks associated with operative therapy of vestibular vertigo. Results of function-preserving and ablative therapies are compared. Surgical treatment of Menière's syndrome (non-idiopathic) using tympanostomy tubes is indicated in cases of increased middle ear pressure; Meniere's disease (idiopathic) in its early stages can be treated with the endolymphatic shunt operation to preserve hearing and balance functions and where these techniques fail, with vestibular neurectomy for preservation of hearing or with cochleosacculotomy in the case of deafness. Rare indications are intractable benign paroxysmal positional vertigo and superior semicircular canal dehiscence syndrome (SCDS). The function preservation success rate in cases of Meniere's syndrome and disease is 70-88 %, ablative procedures are effective in > 90 % of cases and occlusion of the superior or posterior canals is successful in > 95 % of patients.

Otolith-ocular responses in Meniere's patients before and after endolymphatic shunt operation

Caloric testing in prone/supine position and constant velocity off-vertical axis rotation (OVAR) in yaw axis (rotate-then-tilt paradigm) can evaluate labyrinth function and vestibular-ocular reflex (VOR) behaviour before and after endolymphatic shunt surgery (ESS). Preoperative and postoperative otolith dysfunction can be documented by constant velocity OVAR, before the VOR is modulated by the vestibular compensation. Vestibulo-ocular responses in prone/supine position and linear VOR (lVOR) OVAR responses were observed in 10 patients before and after ESS. Ipsilateral caloric reaction in prone/supine position was reduced after ESS. Otolith-ocular function and canal-otolith-interaction were improved postoperatively. Meniere's patients with bias component opposite to normal when rotating towards the lesioned ear showed relief of symptoms postoperatively. The bias component returning to normal can help to identify the relief of Meniere's attacks after ESS. The canal-otolith interaction can be observed pre- and postoperatively by means of caloric reaction in prone/supine position as part of the clinical routine.

Endolymphatic Shunt Operation: Indications and Technique

Educational objectives: To understand the indications for modalities of treatment and the surgical technique of shunt surgery.

Clinical studies on the furosemide VOR test

In order to detect vestibular endolymphatic hydrops, the directional preponderance of the VOR gain (VOR-DP%) during sinusoidal rotation (freq. 0.1Hz; Amp. 120deg) was calculated and compared between pre- and post-intravenous injections of furosemide (20mg). Abnormal changes in VOR-DP% (> = 10%) from the pre-injection level were referred to as positive in this furosemide VOR test (FVOR). The following results were obtained from this study. (1) Positive responses were obtained in 31 of 61 (51%) patients with definite Meniere's disease, in 11 of 21 (52%) patients with delayed endolymphatic hydrops and in 7 of 10 (70%) with syphilitic labyrinthitis. In contrast, the majority of patients responded negatively with sudden deafness or other peripheral vestibular disorders. (2) Following the endolymphatic shunt operation, in 2 out of 3 patients (67%) in whom vertiginous attacks had been decreased or disappeared after the operation results changed from positive to negative. (3) The positive rate in Meniere's disease was dependent on the frequency of the vertiginous attacks before the test or the duration from the last attack to the test. (4) Combined with the glycerol dehydration test or electrocochleography, the FVOR test could detect endolymphatic hydrops of Meniere's disease at a high positive rate. (5) There were no side-effects of the furosemide on the inner ear, such as deterioration of hearing acuity or tinnitus. In conclusion, the FVOR test is useful for detecting and following up fluctuating vestibular endolymphatic hydrops, which occur in disorders such as Meniere's disease, delayed endolymphatic hydrops and syphilitic labyrinthitis.

Endolymphatic shunt: an evaluation by test results.

Failure in the endolymphatic shunt operation for Meniere's disease is reportedly 30% or more. The fact that many patients have relief from their symptoms following this surgery offers validity to the procedure. Pure tone audiograms and sinusoidal harmonic acceleration (rotary chair or rotary test, RT) were used concurrently to evaluate end-results of this operation in 31 patients with Meniere's disease. RT shows parameters of phase and labyrinthine preponderance (LP) calculated by a computer. LP was determined by separately integrating the total slow-phase output of the vestibulo-ocular reflex (VOR) to the left and right and converting the differences to percentages. Irritative and destructive lesions in Meniere's disease may be accurately resolved using this technique. It was not possible to predict with any accuracy the irritative-destructive parameter using pure tone audiometry. Patients who had irritative lesions fared better with the shunt operation. An analysis of these patients is made with RT.

Significance of the Furosemide Test in the Endolymphatic Shunt Operation

We applied the Furosemide test using pendular rotation stimuli to the patients with Meniere's disease for the purpose of diagnosis of endolymphatic hydrops. In patients with probable Meniere's disease, after the administration of Furosemide in doses of 20mg intravenously, the DP index of the pendular rotation test improved to within normal ranges, as a result of prompt diuretic activity.In this report, we evaluated 4 patients with Meniere's disease who have been given the Furosemide test before and after the endolymphatic shunt operation. Three of 4 patients with Meniere's disease showed a positive Furosemide test while the other patient showed a negative Furosemide test, before the operation. The surgery was the endolymphatic shunt operation, by Naito's 2nd method. After the operation, the Furosemide test was again performed in the 4 patients. The results were all negative. In patients with a positive Furosemied test before the operation, the prognosis of the disease was good and they had no further attacks of vertigo. In the other patient with negative test results before the operation, episodes of vertigo persisted.Thus, it is considered that a positive Furosemide test can be used as a diagnostic as well as a prognostic tool and also may be used to determine indications for surgery.

Clinical and experimental studies on pendular rotation test before and after furosemide administration (author's transl)

For the purpose of detecting endolymphatic hydrops, the author developed test for pendular rotation (the furosemide test) and clinically applied the test on patients with Meniere's disease and patients with other peripheral or central vertiginous disorders. It was also experimentally studied on guinea pigs with endolymphatic hydrops induced by surgical obliteration of unilateral endolymphatic sac and on normal ones. In the present report, the author concluded that this test would be a useful method for diagnosis of endolymphatic hydrops.1. Twenty seven out of 60 patients with Meniere's disease (45%) were positive on the furosemide test. Of the above 60, 39 were tested in the attack stage and 25 (64%) were positive, but among the 21 patients tested in their remission stages, only 2 (10%) were positive.2. The patients with Meniere's disease who had been positive on the furosemide test before the endolymphatic shunt operation all had uneventful post-operative courses without any further attacks.3. None of the 25 patients who had vertigo with other causes than Meniere's disease were positive on the furosemide test whether they were in peripheral or central disorders.4. The guinea pigs with experimental endolymphatic hydrops induced by surgical obliteration of unilateral endolymphatic sac showed positive results in the furosemide test in a similar way as Meniere's disease patients.5. The histological view of the inner ears of the guinea pigs with positive furosemide test revealed either normalizing or collapsing of the endolymphatic hydrops once produced in the affected ear, while the opposite ear was almost normal.6. In the control group of normal guinea pigs, the positive furosemide test was not found, and histologically the bilateral inner ears of them had almost normal endolymphatic space.

Long Term Observation of Meniere's Disease Following the Endolymphatic Shunt Operation

大阪大学耳鼻咽喉科で行ったメニエール病に対する subarachnoid shunt operation (山川, 内藤法第1法, 第2法) の手術後経過について, アンケート調査を行った結果を報告した.1951年から1956年までの5年間に行った手術症例の20年後の術後経過 (1971年6月集計) では, 回答を得た3例中, めまいの消失は2例, 軽快 (時々めまいがある) は1例, 耳鳴の軽快は2例, 不変は1例, 難聴の改善は1例, 不変は2例であった. 約30年後の術後経過 (1979年2月集計) では, 回答を得た2例は, 1例の難聴の悪化を除いて, 1971年の集計と同じであった.1971年から1977年までの6年間に行った手術症例の回答を得た13例中の3年ないし8年間の術後経過では, めまいの全くの消失は4例, 改善は6年, 軽快は3例で, 悪化, 不変は1例もなく, 少くとも手術を行えば, 何等かのめまいの改善が認められた. 難聴の改善は2例, 不変は8例, 悪化は3例であった. 耳鳴の軽快は4例, 不変は8例, 悪化は1例であった. 全例共手術してよかったと回答した.

The surgical treatment of Ménière's disease.

Ménière's disease is more common than was generally believed in the past. Stahle has calculated the incidence of Ménière's disease in Sweden. Using the same incidence for the United States, there ought to be 97,000 hospitalized inpatients with Ménière's disease of all ages in the whole population. The increased understanding of inner ear physiology and pathology during the past decade has changed the indication for operation towards an early intervention for preserving the hearing function.For the purposes of analyzing results, patients with Ménière's disease were divided into the following classes according to the hearing loss only: 1. Near normal hearing (no more than 10 db loss at 500, 1,000, 2,000). 2. Ascending audiogram, fluctuating (500 more than 10 db more than 2,000). 3. Flat audiogram, fluctuating (500 not 10 db different than 2,000). 4. Flat audiogram, non‐fluctuating (500 not 10 db different than 2,000). 5. Other, more extreme hearing loss, non‐fluctuating (2,000 10 db more than 500).In this study, 33 patients with early Ménière's disease had a subarachnoid endolymphatic shunt operation. Two patients belonged to Class 1 and 31 patients to Class 2. All had well‐visualized vestibular aqueducts on polytomography and most had a positive glycerin test done in conjunction with transtympanic electrocochleography.During the first postoperative year, two patients in Class 2 improved to Class 1 (normal hearing). The other 29 in Class 2 remained in Class 2. None was worse as regards hearing. Most were completely relieved or improved as regards vertigo.Early surgical drainage in Ménière's disease is effective and safe and should be performed prior to irreversible dilatation of the membranous labyrinth. Patients in Classes 3, 4, and 5, with excessive and widespread hydrops of the membranous labyrinth, should have a vestibular nerve section.

The Endolymphatic Shunt Operation

The Endolymphatic Shunt Operation

SHORT TERM STUDY OF ENDOLYMPHATIC SHUNT OPERATION.

SURGICAL TREATMENT of Meniere's disease has been of two basic types, destructive and conservative. Relief of vertigo without loss of cochlear function is the objective of conservative surgery, but this is a difficult ideal, and until recent times most operations performed were destructive in nature. Loss of hearing was felt to be a tolerable disability to secure relief of incapacitating vertigo, particularly in a disease which usually terminated in severe hearing loss. Early methods of surgical treatment were intercranial section of the auditory nerve ( 1904) 1 and opening of the semicircular canals and vestibule ( 1904). 2,3 The earliest attempt at conservatism was that of Barany 4 who in 1912 described relieving vertigo by elevation of the dura from the posterior face of the temporal bone. In 1927 Georges Portmann 5 described the procedure bearing his name. Portmann felt that by opening the endolymphatic space, relief of the hydrops could be