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Mohammad SA, Albulaihed SA, Ismail M, Alshuqayfi KM, Farooq IA, Al-Ageely TA, Palmisciano P, Andaluz N, Hoz SS. Endolymphatic sac: A surreptitious anatomy for neurosurgeons. Surg Neurol Int 2023; 14:42. [PMID: 36895224 PMCID: PMC9990765 DOI: 10.25259/sni_1168_2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 01/19/2023] [Indexed: 02/05/2023] Open
Affiliation(s)
- Sara A Mohammad
- Department of Neurosurgery, University of Baghdad - College of Medicine, Baghdad, Iraq
| | | | - Mustafa Ismail
- Department of Neurosurgery, Neurosurgery Teaching Hospital, Baghdad, Iraq
| | - Khalid M Alshuqayfi
- Department of Neurosurgery, University of King Abdulaziz - College of Medicine, Jeddah, Saudi Arabia
| | - Ibrahim A Farooq
- Department of Neurosurgery, University of Baghdad - College of Medicine, Baghdad, Iraq
| | - Teeba A Al-Ageely
- Department of Neurosurgery, University of Baghdad - College of Medicine, Baghdad, Iraq
| | - Paolo Palmisciano
- Department of Neurosurgery, University of Cincinnati, Cincinnati, Ohio, United States
| | - Norberto Andaluz
- Department of Neurosurgery, University of Cincinnati, Cincinnati, Ohio, United States
| | - Samer S Hoz
- Department of Neurosurgery, University of Cincinnati, Cincinnati, Ohio, United States
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Li H, Rajan GP, Shaw J, Rohani SA, Ladak HM, Agrawal S, Rask-Andersen H. A Synchrotron and Micro-CT Study of the Human Endolymphatic Duct System: Is Meniere's Disease Caused by an Acute Endolymph Backflow? Front Surg 2021; 8:662530. [PMID: 34136526 PMCID: PMC8200827 DOI: 10.3389/fsurg.2021.662530] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/19/2021] [Indexed: 11/13/2022] Open
Abstract
Background: The etiology of Meniere's disease (MD) and endolymphatic hydrops believed to underlie its symptoms remain unknown. One reason may be the exceptional complexity of the human inner ear, its vulnerability, and surrounding hard bone. The vestibular organ contains an endolymphatic duct system (EDS) bridging the different fluid reservoirs. It may be essential for monitoring hydraulic equilibrium, and a dysregulation may result in distension of the fluid spaces or endolymphatic hydrops. Material and Methods: We studied the EDS using high-resolution synchrotron phase contrast non-invasive imaging (SR-PCI), and micro-computed tomography (micro-CT). Ten fresh human temporal bones underwent SR-PCI. One bone underwent micro-CT after fixation and staining with Lugol's iodine solution (I2KI) to increase tissue resolution. Data were processed using volume-rendering software to create 3D reconstructions allowing orthogonal sectioning, cropping, and tissue segmentation. Results: Combined imaging techniques with segmentation and tissue modeling demonstrated the 3D anatomy of the human saccule, utricle, endolymphatic duct, and sac together with connecting pathways. The utricular duct (UD) and utriculo-endolymphatic valve (UEV or Bast's valve) were demonstrated three-dimensionally for the first time. The reunion duct was displayed with micro-CT. It may serve as a safety valve to maintain cochlear endolymph homeostasis under certain conditions. Discussion: The thin reunion duct seems to play a minor role in the exchange of endolymph between the cochlea and vestibule under normal conditions. The saccule wall appears highly flexible, which may explain occult hydrops occasionally preceding symptoms in MD on magnetic resonance imaging (MRI). The design of the UEV and connecting ducts suggests that there is a reciprocal exchange of fluid among the utricle, semicircular canals, and the EDS. Based on the anatomic framework and previous experimental data, we speculate that precipitous vestibular symptoms in MD arise from a sudden increase in endolymph pressure caused by an uncontrolled endolymphatic sac secretion. A rapid rise in UD pressure, mediated along the fairly wide UEV, may underlie the acute vertigo attack, refuting the rupture/K+-intoxication theory.
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Affiliation(s)
- Hao Li
- Department of Surgical Sciences, Section of Otolaryngology and Head and Neck Surgery, Uppsala University Hospital, Uppsala, Sweden
| | - Gunesh P. Rajan
- Department of Otolaryngology, Head and Neck Surgery, Luzerner Kantonsspital, Lucerne, Switzerland
- Department of Otolaryngology, Head and Neck Surgery Division of Surgery, Medical School, University of Western Australia, Perth, WA, Australia
| | - Jeremy Shaw
- Centre for Microscopy, Characterisation and Analysis, Perth, WA, Australia
| | - Seyed Alireza Rohani
- Department of Otolaryngology-Head and Neck Surgery, Western University, London, ON, Canada
| | - Hanif M. Ladak
- Department of Medical Biophysics and Department of Electrical and Computer Engineering, Western University, London, ON, Canada
| | - Sumit Agrawal
- Department of Otolaryngology-Head and Neck Surgery, Western University, London, ON, Canada
| | - Helge Rask-Andersen
- Department of Surgical Sciences, Section of Otolaryngology and Head and Neck Surgery, Uppsala University Hospital, Uppsala, Sweden
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Tsukada K, Usami SI. Detailed MR imaging assessment of endolymphatic hydrops in patients with SLC26A4 mutations. Auris Nasus Larynx 2020; 47:958-964. [PMID: 32536503 DOI: 10.1016/j.anl.2020.05.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 05/02/2020] [Accepted: 05/27/2020] [Indexed: 10/24/2022]
Abstract
OBJECTIVE Mutations in SLC26A4 represent the second most common mutations in deafness patients. The majority of patients with SLC26A4 mutations have a large vestibular aqueduct (LVA). Recently, some reports showed the presence of endolymphatic hydrops (ELH) in patients with LVA on the basis of high-resolution enhanced 3T-MRI. However, detailed evaluation has not been performed. We provide the first report on ELH in LVA patients with biallelic SLC26A4 mutations. In this study, we focused on 1) the findings of ELH in LVA patients with biallelic SLC26A4 mutations, and 2) the findings of the endolymphatic duct (ED) and endolymphatic sac (ES) by using two different gadodimide (Gd) enhancement methods. SUBJECTS AND METHODS Five patients with SLC26A4 mutations underwent enhanced 3T-MRI using the intratympanic (IT) or intravenous (IV) injection of Gd for the diagnosis ELH. RESULTS All of the patients had ELH in at least one ear. ELH was identified in the vestibule (8/10 ears) as well as in the cochlea (7/10 ears). With regard to the ED and ES, all ears for which MRI was performed with an IT injection of Gd had black areas in the ES or VA or both; however, all of the ears receiving an IV injection had no black areas and were well enhanced. CONCLUSIONS A majority of the patients had severe ELH in the cochleo-vestibular endolymph, with two different patterns observed in the MRI findings of the ED and ES.
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Affiliation(s)
- Keita Tsukada
- Department of Otolaryngology, Shinshu University School of Medicine, 3-1-1, Asahi, Matsumoto City, 390-8621, Japan
| | - Shin-Ichi Usami
- Department of Otolaryngology, Shinshu University School of Medicine, 3-1-1, Asahi, Matsumoto City, 390-8621, Japan.
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Pradhananga R, Natarajan K, Devarasetty A, Kameswaran M. Cochlear Implantation in Isolated Large Vestibular Aqueduct Syndrome: Report of Three Cases and Literature Review. Int Arch Otorhinolaryngol 2014; 19:359-63. [PMID: 26491485 PMCID: PMC4593917 DOI: 10.1055/s-0034-1395791] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Accepted: 10/11/2014] [Indexed: 11/06/2022] Open
Abstract
Introduction Large vestibular aqueduct syndrome (LVAS) is characterized by the enlargement of the vestibular aqueduct associated with sensorineural hearing loss. It is the most common radiographically detectable inner ear anomaly in congenital hearing loss. LVAS may occur as an isolated anomaly or in association with other inner ear malformations. Objective To report three cases of isolated LVAS with a focus on preoperative assessment, surgical issues, and short-term postoperative follow-up with preliminary auditory habilitation outcomes. Resumed Report One girl and two boys with LVAS were assessed and cochlear implantation was performed for each. Various ways of intraoperative management of cerebrospinal fluid gusher and postoperative care and outcomes are reported. Conclusion Cochlear implantation in the deaf children with LVAS is feasible and effective.
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Affiliation(s)
- Rabindra Pradhananga
- Department of ENT-Head and Neck Surgery, Tribhuvan University Teaching Hospital, Kathmandu, Nepal ; Department of Implantation Otology, Madras ENT Research Foundation, Chennai, Tamil Nadu, India
| | - Kiran Natarajan
- Department of Otorhinolaryngology, Madras ENT Research Foundation, Chennai, Tamil Nadu, India
| | - AmarNath Devarasetty
- Department of Otorhinolaryngology, Madras ENT Research Foundation, Chennai, Tamil Nadu, India
| | - Mohan Kameswaran
- Department of Implantation Otology, Madras ENT Research Foundation, Chennai, Tamil Nadu, India
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Magnetic resonance imaging features of large endolymphatic sac compartments: audiological and clinical correlates. The Journal of Laryngology & Otology 2012; 126:586-93. [PMID: 22643203 DOI: 10.1017/s0022215112000606] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVES (1) To study the prevalence and characteristics of large endolymphatic sac internal compartments on thin-section T2- and T2*-weighted magnetic resonance imaging, and to relate these to other large endolymphatic sac magnetic resonance imaging features, and (2) to correlate the compartment imaging features, endolymphatic sac size and labyrinthine anomalies with the patients' clinical and audiological data. METHOD Magnetic resonance imaging studies for 38 patients with large endolymphatic sac anomalies were retrospectively reviewed in a tertiary referral centre. Endolymphatic sac compartment presence, morphology and imaging signal were assessed. Endolymphatic sac size and labyrinthine anomalies were also recorded. Endolymphatic sac compartments and other imaging features were correlated with clinical and audiological data. RESULTS Compartments were present in 57 per cent of the imaged endolymphatic sacs, but their presence alone did not correlate with other imaging features or clinical data. The endolymphatic sac : internal auditory meatus signal ratio was associated with a history of sudden or fluctuating hearing loss. Hearing loss correlated with opercular and extraosseous endolymphatic sac size measurements. A larger midpoint intraosseous endolymphatic sac size was associated with clear fluid loss at cochlear implantation. CONCLUSION The magnetic resonance imaging characteristics of large endolymphatic sac compartments have been defined. The endolymphatic sac size and distal compartment signal should be recorded, as these provide prognostic information and assist the planning of appropriate interventions.
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Objective Measurement of the Human Endolymphatic Sac Dimensions in Ménière's Disease. Otol Neurotol 2011; 32:1364-9. [DOI: 10.1097/mao.0b013e31822e967f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
The endolymphatic sac is believed to represent one of the primary loci for endolymph volume regulation in the inner ear. Quantitative analysis of physiologic measurements from the endolymphatic sac requires knowledge of the anatomy of the structure, specifically the luminal volume and the variation of cross-sectional area with distance along the sac. Recently techniques have become available to make these measurements. In the present study, fixed, isolated specimens of the guinea pig endolymphatic sac were imaged by high-resolution magnetic resonance microscopy (MRM) or by histological serial sections. Structures were reconstructed and quantified using image analysis software. In specimens imaged by MRM the endolymphatic sac volume, including tissue and lumen, was 359 nl for the intraosseous region and 106 nl for the extraosseous region, totaling 465 nl for the entire structure. The luminal volumes were 131 nl for the intraosseous region and 13 nl for the extraosseous region, totaling 144 nl. In histological specimens the volume, including tissue and lumen, was 414 nl for the intraosseous region and 121 nl for the extraosseous region, totaling 535 nl for the entire structure. The luminal volumes were 152 nl for the intraosseous region and 26 nl for the extraosseous region, totaling 179 nl. Differences in volume estimates obtained by the two methods were not statistically significant and variation was dominated by inter-specimen variation. Pooling the data, the total volume of the endolymphatic sac in the guinea pig including tissue and lumen was 506 nl (S.D. 100, n=17) and the volume of the lumen was 169 nl (S.D. 48, n=14).
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Affiliation(s)
- Kelli Pettit
- Department of Otolaryngology, Box 8115, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA
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Mafee MF. Congenital sensorineural hearing loss and enlarged endolymphatic sac and duct: role of magnetic resonance imaging and computed tomography. Top Magn Reson Imaging 2000; 11:10-24. [PMID: 10782723 DOI: 10.1097/00002142-200002000-00004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
During the past 20 years, there have been significant advances in cochlear implants as the treatment of choice for profoundly hearing-impaired children. The increasing application of cochlear implant has brought with it an increase in the investigational use of computed tomography and magnetic resonance imaging. In this article, the author reviews (a) the anatomy and embryology of the inner ear, (b) the pathological changes associated with congenital sensorineural hearing loss (SNHL), and (c) the spectrum of imaging findings in patients with SNHL.
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Affiliation(s)
- M F Mafee
- Department of Radiology, University of Illinois, Chicago 60612, USA
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Abstract
The adult human endolymphatic sac (ES) has been described as a complex network of interconnected tubules. Embryologic examination describes the human ES as a single-lumen, pouch-like structure. Transition from saccular shape to tubules during the entire fetal period has not been previously reported. Tubular ES structure is thought to be unique to humans. Animal investigations describe similar saccular appearance, but without tubules in mature sacs. The authors examined 45 human fetal temporal bones to trace ES development and reviewed six types of animal sacs. Results in humans reveal tubular structure as early as 26 weeks' gestation. Maturation variably occurred in the fetal period and postnatally. For the first time, the tubular system is noted in the animal, the rhesus monkey. These findings suggest that the tubular system may represent more advanced specialized function.
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Affiliation(s)
- M Ng
- Department of Otolaryngology-Head and Neck Surgery, University of Southern California School of Medicine, Los Angeles 90033, USA
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Gibson MD WPR, Kaufman Arenberg I. Pathophysiologic Theories In The Etiology Of Meniere’s Disease. Otolaryngol Clin North Am 1997. [DOI: 10.1016/s0030-6665(20)30139-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Moffat DA. Endolymphatic Mastoid Shunt Surgery in Unilateral Meniere's Disease. EAR, NOSE & THROAT JOURNAL 1997. [DOI: 10.1177/014556139707600909] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
One-hundred endolymphatic mastoid shunt operations in patients with classic unilateral Meniere's disease were analyzed. The patients were carefully preselected with a comprehensive protocol of audiovestibular and metabolic investigations. All patients had definitive electrophysiologic evidence of endolymphatic hydrops with an enhanced negative summating potential on transtympanic electrocochleography. The surgical results were analyzed both by the original American Academy of Ophthalmology and Otolaryngology Guidelines (AAOO, 1972), and the more recent modifications of the American Academy of Otolaryngology— Head and Neck Surgery (AA-HNS, 1985). Control of vertigo was achieved in 79% of the patients overall, with 42% sustaining complete control and 37% substantial control. A significant hearing improvement was obtained in 15% of cases, there was no change in 56% of patients, and hearing became worse in 29%. Tinnitus improved following surgery in 35% of patients, was the same in 56%, and worse in 9%. Postoperatively, there was no disability in 42% of the patients, some degree of disability in 50%, and severe disability and inability to sustain gainful employment in only 8%.
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Gibson WP. The effect of surgical removal of the extraosseous portion of the endolymphatic sac in patients suffering from Menière's disease. J Laryngol Otol 1996; 110:1008-11. [PMID: 8944872 DOI: 10.1017/s0022215100135637] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Between April 1990 and June 1996, the extraosseous portion of endolymphatic sac has been removed from the affected ear in 77 patients suffering from Menière's disease. Removal of the extraosseous part of the endolymphatic sac without any drainage procedure did not increase the frequency or severity of the attacks of vertigo in any patient. The results of 43 patients with unilateral disease who had a follow-up period of two years are presented. Only eight of the patients had more than two recurrent attacks of vertigo lasting over two minutes within the two years after the surgery, and in three of these patients the severity of the attacks was greatly reduced. In 56 per cent of the operated ears, the hearing deteriorated at least 10 dBHL across five audiometric frequencies (250 Hz, 500 Hz, 1 kHz, 2 kHz and 3 kHz). To the author, endolymphatic sac removal appeared to provide better relief from vertigo than a simple drainage procedure with less tendency for recurrence several months or years after the initial surgery. At present, the statistical analysis of the results shows no significant difference between removal of the extraosseous portion of the endolymphatic sac and the "so called' endolymphatic sac drainage procedures.
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Affiliation(s)
- W P Gibson
- Department of Surgery, University of Sydney, Australia
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Salt AN, Henson MM, Gewalt SL, Keating AW, DeMott JE, Henson OW. Detection and quantification of endolymphatic hydrops in the guinea pig cochlea by magnetic resonance microscopy. Hear Res 1995; 88:79-86. [PMID: 8576007 DOI: 10.1016/0378-5955(95)00103-b] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Three-dimensional magnetic resonance microscopy (MRM) was used to study normal and hydropic cochleae of the guinea pig. With this technique consecutive serial slices representing the entire volume of isolated, fixed cochleae were obtained. The voxels (volume elements) making up the contiguous slices were isotropic (25 microns 3) and in each slice the boundaries of scala media, including the position of Reissner's membrane, were clearly delineated. Three-dimensional reconstructions of the endolymphatic and perilymphatic scale were generated. Custom software was developed to quantify cross-sectional area (CSA) of all scalae. In the normal cochlea all 3 scalae, including scala media, showed a gradual decrease in CSA from base to apex. Marked differences existed between our findings and previously reported cochlear dimensions, especially for the perilymphatic scalae in the basal turn. In hydropic cochleae the scala media was enlarged to a varying extent in different turns and marked changes in the degree of distension of Reissner's membrane occurred along the cochlea. MRM and subsequent computer analysis of the isotropic data provide excellent methods for imaging and quantifying the fluid spaces of normal and hydropic cochleae.
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Affiliation(s)
- A N Salt
- Department of Otolaryngology, Washington University Medical School, St. Louis, MO 63110, USA
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