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Sudden sensorineural hearing loss as a presenting symptom in superior semicircular canal dehiscence
Otolaryngology Case Reports 12 (2019) 100122
Contents lists available at ScienceDirect
Otolaryngology Case Reports journal homepage: www.elsevier.com/locate/xocr
Sudden sensorineural hearing loss as a presenting symptom in superior semicircular canal dehiscence
T
Ravi R. Shah∗, James G. Naples, Michael J. Ruckenstein, Steven J. Eliades Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, PA, USA
ARTICLE INFO
ABSTRACT
Keywords: Superior semicircular canal dehiscence Sudden sensorineural hearing loss Third window
Purpose: To provide new insights into a potential mechanism of sudden sensorineural hearing loss (SSNHL) in superior semicircular canal dehiscence (SCD). Materials and methods: This study is a retrospective case series of three adult subjects who presented with acute SSNHL and vestibular symptoms, with computed tomography (CT) findings suggestive of SCD. Subjects were evaluated with magnetic resonance imaging (MRI) and computed tomography (CT) imaging of the temporal bone along with audiometric and vestibular testing. Appropriate medical intervention was offered, and surgical intervention was discussed with all patients. Main outcome measures included clinical symptoms, audiometry, vestibular testing, cervical vestibular evoked myogenic potentials, and imaging. Results: All three patients had sudden onset of symptoms, with audiometry consistent with SNHL and imaging demonstrating SCD. One patient recovered normal hearing after intratympanic steroid injections. Conclusions: These cases represent an unusual presentation of possible SCD and may represent a new, unrecognized etiology of SSNHL. These cases suggest that there may be utility in offering CT scans of the temporal bone in the setting of sudden hearing loss when MRI is negative and vestibular symptoms persist. Rupture of the underlying membranous labyrinth may provide a plausible explanation for the presentation of SSNHL with the onset of SCD symptoms.
Introduction Patients with superior semicircular canal dehiscence (SCD) syndrome classically present with sound- or pressure-induced vestibular symptoms. Auditory symptoms are often limited to autophony, hyperacusis, or tinnitus [1]. The dehiscence of the bony labyrinth overlying the canal creates a third window effect that exposes the membranous labyrinth and accounts for symptoms. Hearing is often minimally affected, ranging from normal hearing to low-frequency conductive hearing loss (CHL) [2]. While more significant hearing loss can be a complication of surgical correction of SCD, sudden sensorineural hearing loss (SSNHL) is not currently recognized as a phenomenon related to the development of SCD. Here we describe three patients who presented with SSNHL and were found to have SCD on the side of the hearing loss. Given that these entities have not previously been corre-
lated, we present these cases to propose a mechanism explaining SSNHL as a presenting symptom in SCD. We theorize that rupture of the exposed membranous labyrinth at the site of dehiscence is responsible for the SSNHL. Case presentations Case 1: A 44-year-old male presented to our clinic 3 years after right-sided sudden hearing loss. At the time of the initial event, he had received oral steroids without benefit, and an MRI of the head was unremarkable. At the time of referral, he noted 6 months of subjective progression of hearing loss, tinnitus, imbalance induced by manipulation of the external ear, and Tullio phenomenon. Neurotologic exam was normal without peripheral vestibular dysfunction or nystagmus. His audiogram showed a 65–70 dB (dB) SNHL in all frequencies with a
Abbreviations: BMI, body mass index; CHL, conductive hearing loss; CT, computed tomography; cVEMPs, cervical vestibular evoked myogenic potentials; IT, intratympanic; MRI, magnetic resonance imaging; SCD, semicircular canal dehiscence; SSNHL, sudden sensorineural hearing loss; WRS, word recognition score ∗ Corresponding author. Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania, 5th Floor Silverstein Building, 3400 Spruce St, Philadelphia, PA, 19104, USA. E-mail address: [email protected] (R.R. Shah). https://doi.org/10.1016/j.xocr.2019.100122 Received 17 November 2018; Received in revised form 4 May 2019; Accepted 22 May 2019 Available online 04 June 2019 2468-5488/ © 2019 Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/).
Otolaryngology Case Reports 12 (2019) 100122
R.R. Shah, et al.
Fig. 1. A: Case 1, pure tone audiometry. Right ear shows moderately severe to severe sensorineural hearing loss. Left ear shows normal hearing sensitivity from 250 Hz to 4 kHz, sloping to a mild sensorineural hearing loss in the high frequencies. B: Case 3, pure tone audiometry. Right ear shows normal hearing sensitivity from 250 Hz to 8 kHz. Left ear shows normal hearing sensitivity from 250 Hz to 6 kHz, sloping to a severe sensorineural hearing loss at 8 kHz.
16% word recognition score (WRS) on the right, and high-frequency SNHL on the left (Fig. 1A). A computed tomography (CT) scan of the temporal bone demonstrated right SCD without other abnormalities (Fig. 2A and B). Vestibular testing was notable for a 52% relative vestibular reduction on the right. Cervical vestibular evoked myogenic potentials (cVEMPs) demonstrated relative reduction of thresholds on the right (85 dBnHL right, 95 dBnHL left). He elected to pursue hearing amplification and deferred surgical intervention for SCD. Case 2: A 27-year-old female presented 5 days after sudden leftsided hearing loss and vertigo. She suffered a motor vehicle collision without clear head trauma about one month prior to presentation. She was started on a 60 mg oral prednisone taper prior to referral without
immediate benefit. Neurotologic exam was normal. Her audiogram showed moderate SNHL in the left ear with a 0% WRS, and normal hearing in the right (Fig. 3A). Intratympanic (IT) dexamethasone was administered to the left ear. An MRI did not reveal any retrocochlear pathology but was suggestive of SCD. Labs consisting of CBC, TSH, ESR, and ANA were normal. Follow up audiogram at 1 week showed 5–10 dB improvement in bone conduction. Because of her nonspecific vestibular symptoms and MRI suggestive of SCD, CT of the temporal bones was ordered, which more clearly demonstrated dehiscence of the left superior semicircular canal (Fig. 2C and D). She underwent 2 additional IT dexamethasone injections and repeat audiograms demonstrated significant improvement in hearing with 92% word recognition scores
2
Otolaryngology Case Reports 12 (2019) 100122
R.R. Shah, et al.
Clinical judgment must be exercised when interpreting CT due to incidental findings of SCD [3]. Nonetheless, these cases raise the possibility that CT may identify possible etiologies of SSNHL that MRI cannot resolve. We obtained CT scans of the temporal bones in the described patients because they had specific findings that suggested a third window effect and SCD. Cases 1 and 3 both reported Tullio phenomenon, and Case 2 reported nonspecific vestibular symptoms with an MRI suggestive of SCD. The question remains as to whether or not there is any association between our patients’ SCD and SSNHL. It is well-recognized that violation of the membranous labyrinth causes deafness and labyrinthitislike symptoms [4]. Given that our patients had symptoms consistent with a labyrinthitis-like event, rupture of the membranous labyrinth in the dehiscent superior canal provides a plausible explanation for the SSNHL. In the setting of SCD, bony dehiscence may occur as a consequence of a traumatic event or chronic pressure from the temporal lobe, resulting in the acute onset of third window symptoms [5,6]. We propose that fracture of this thin bone may also occasionally rupture the membranous labyrinth, thus causing SSNHL in some patients in addition to third-window symptoms. Imaging techniques to improve resolution of the inner ear and membranous labyrinth could potentially provide additional insights to this notion in the future. Although the possibility exists that our patients’ SSNHL was due to an event unrelated to the SCD, their history and workup did not suggest any other etiologies. It is challenging to explain why one patient recovered hearing and the others did not, however. The steroid-responsiveness in Case 2 could have indicated isolated labyrinthitis with coincidental ipsilateral SCD. Alternatively, steroids may have been beneficial due to their effect on local inflammation from a membranous rupture, or perhaps a small membranous rupture may have spontaneously sealed before permanent damage ensued. Case 2 also had normal cVEMPs. One study found that cVEMPs to click stimuli have a sensitivity of 92% and specificity of 97% at 90 dBnHL [7]. However, despite their usefulness, cVEMP thresholds do not always correlate well with symptoms, and it is possible that the area of dehiscence was too small to have reduced cVEMPs [8]. These cases also allude to the challenging management of patients presenting with SSNHL who are found to have SCD. SSNHL is treated with oral and/or IT steroids. However, management of the SCD in this setting is less clear. If the SSNHL was due to a self-sealing rupture of the membranous labyrinth, there may be a risk of future similar episodes that could impact hearing. While surgery for SCD is safe, hearing loss is not currently an indication for repair, and the surgery itself can risk residual hearing [1]. Ultimately, therapeutic decision-making requires discussion between the patient and physician in this unusual scenario. Further investigations looking at the association of SCD and SSNHL may provide deeper understanding of both diagnostic and treatment dilemmas.
Fig. 2. Noncontrast CT of the temporal bones for Cases 1–3. A-B: Case 1, right temporal bone. Pöschl (A) and Stenvers (B) projections demonstrate dehiscence of the right superior semicircular canal (arrows). C-D: Case 2, left temporal bone. Pöschl (C) and Stenvers (D) projections demonstrate dehiscence of the left superior semicircular canal (arrows). E-F: Case 3, left temporal bone. Pöschl (E) and Stenvers (F) projections demonstrate dehiscence of the left superior semicircular canal (arrows).
(Fig. 3B and C). Vestibular testing was normal, and cVEMPs were normal (100 dBnHL bilaterally). Given the return of her hearing, and persistent but tolerable occasional vertigo, the patient elected not to pursue additional treatment. Case 3: A 35-year-old male presented to our clinic 6 years after leftsided sudden hearing loss. His symptoms began after several hours of excessive noise exposure. Accompanying symptoms included ipsilateral aural fullness, tinnitus, dizziness exacerbated by movement, and Tullio phenomenon. Symptoms gradually improved over several months but recurred 2 weeks prior to presentation. Neurotologic exam was normal. His audiogram showed normal hearing from 250 to 6000 Hz on the left sloping to severe loss at 8000 Hz (Fig. 1B), and his vestibular testing was normal. CT of the temporal bone demonstrated a left SCD without other abnormalities (Fig. 2E and F). Cervical VEMPs demonstrated reduced thresholds on the left (55 dBnHL left, 85 dBnHL right). He deferred surgical intervention. Discussion SSNHL associated with SCD has not yet been described. In this report, we describe three patients presenting with SSNHL and concomitant vestibular symptoms with findings highly suspicious for SCD on the side of hearing loss. Workup of SSNHL commonly includes MRI to evaluate for retrocochlear lesions. Conversely, in the workup of SCD, CT scan is favored over MRI as a diagnostic measure. Because of differing imaging modalities, SCD may therefore be overlooked in the setting of SSNHL.
Conclusion We illustrate three cases of patients who presented with SSNHL and findings highly suspicious for SCD on the affected side. These cases add insight into possible etiologies of SSNHL and raise a potential argument for the utility of CT scans in helping to identify unrecognized pathology in the workup of SSNHL.
3
Otolaryngology Case Reports 12 (2019) 100122
R.R. Shah, et al.
Fig. 3. Case 2: Pure tone audiometry. A: Audiometry at time of presentation. Right ear hearing within normal. Left ear shows moderate to moderately severe sensorineural hearing loss. B: Audiometry 3 weeks after intratympanic dexamethasone injection shows improvement to mild to moderate hearing loss in the left ear. C: Audiometry 7 weeks after presentation, following 3 intratympanic dexamethasone injections, shows normal hearing in the left ear.
Conflicts of interest [3]
None.
[4]
Appendix A. Supplementary data
[5]
Supplementary data to this article can be found online at https:// doi.org/10.1016/j.xocr.2019.100122.
[6]
References
[7]
[1] Xie Y, Sharon JD, Pross SE, et al. Surgical complications from superior canal dehiscence syndrome repair: two decades of experience. Otolaryngol Head Neck Surg 2017;157(2):273–80. [2] Patel NS, Hunter JB, O'Connell BP, Bertrand NM, Wanna GB, Carlson ML. Risk of
[8]
4
progressive hearing loss in untreated superior semicircular canal dehiscence. The Laryngoscope 2017;127(5):1181–6. Williamson RA, Vrabec JT, Coker NJ, Sandlin M. Coronal computed tomography prevalence of superior semicircular canal dehiscence. Otolaryngol Head Neck Surg 2003;129(5):481–9. Althaus SR. Spontaneous and traumatic perilymph fistulas. The Laryngoscope 1977;87(3):364–71. Carey JP, Minor LB, Nager GT. Dehiscence or thinning of bone overlying the superior semicircular canal in a temporal bone survey. Arch Otolaryngol Head Neck Surg 2000;126(2):137–47. Minor LB. Labyrinthine fistulae: pathobiology and management. Curr Opin Otolaryngol Head Neck Surg 2003;11(5):340–6. Brantberg K, Verrecchia L. Effectiveness of different click stimuli in diagnosing superior canal dehiscence using cervical vestibular evoked myogenic potentials. Acta Otolaryngol 2012;132(10):1077–83. Hunter JB, O'Connell BP, Wang J, et al. Correlation of superior canal dehiscence surface area with vestibular evoked myogenic potentials, audiometric thresholds, and dizziness handicap. Otol Neurotol 2016;37(8):1104–10.
Contents lists available at ScienceDirect
Otolaryngology Case Reports journal homepage: www.elsevier.com/locate/xocr
Sudden sensorineural hearing loss as a presenting symptom in superior semicircular canal dehiscence
T
Ravi R. Shah∗, James G. Naples, Michael J. Ruckenstein, Steven J. Eliades Department of Otorhinolaryngology, Head and Neck Surgery, University of Pennsylvania, Philadelphia, PA, USA
ARTICLE INFO
ABSTRACT
Keywords: Superior semicircular canal dehiscence Sudden sensorineural hearing loss Third window
Purpose: To provide new insights into a potential mechanism of sudden sensorineural hearing loss (SSNHL) in superior semicircular canal dehiscence (SCD). Materials and methods: This study is a retrospective case series of three adult subjects who presented with acute SSNHL and vestibular symptoms, with computed tomography (CT) findings suggestive of SCD. Subjects were evaluated with magnetic resonance imaging (MRI) and computed tomography (CT) imaging of the temporal bone along with audiometric and vestibular testing. Appropriate medical intervention was offered, and surgical intervention was discussed with all patients. Main outcome measures included clinical symptoms, audiometry, vestibular testing, cervical vestibular evoked myogenic potentials, and imaging. Results: All three patients had sudden onset of symptoms, with audiometry consistent with SNHL and imaging demonstrating SCD. One patient recovered normal hearing after intratympanic steroid injections. Conclusions: These cases represent an unusual presentation of possible SCD and may represent a new, unrecognized etiology of SSNHL. These cases suggest that there may be utility in offering CT scans of the temporal bone in the setting of sudden hearing loss when MRI is negative and vestibular symptoms persist. Rupture of the underlying membranous labyrinth may provide a plausible explanation for the presentation of SSNHL with the onset of SCD symptoms.
Introduction Patients with superior semicircular canal dehiscence (SCD) syndrome classically present with sound- or pressure-induced vestibular symptoms. Auditory symptoms are often limited to autophony, hyperacusis, or tinnitus [1]. The dehiscence of the bony labyrinth overlying the canal creates a third window effect that exposes the membranous labyrinth and accounts for symptoms. Hearing is often minimally affected, ranging from normal hearing to low-frequency conductive hearing loss (CHL) [2]. While more significant hearing loss can be a complication of surgical correction of SCD, sudden sensorineural hearing loss (SSNHL) is not currently recognized as a phenomenon related to the development of SCD. Here we describe three patients who presented with SSNHL and were found to have SCD on the side of the hearing loss. Given that these entities have not previously been corre-
lated, we present these cases to propose a mechanism explaining SSNHL as a presenting symptom in SCD. We theorize that rupture of the exposed membranous labyrinth at the site of dehiscence is responsible for the SSNHL. Case presentations Case 1: A 44-year-old male presented to our clinic 3 years after right-sided sudden hearing loss. At the time of the initial event, he had received oral steroids without benefit, and an MRI of the head was unremarkable. At the time of referral, he noted 6 months of subjective progression of hearing loss, tinnitus, imbalance induced by manipulation of the external ear, and Tullio phenomenon. Neurotologic exam was normal without peripheral vestibular dysfunction or nystagmus. His audiogram showed a 65–70 dB (dB) SNHL in all frequencies with a
Abbreviations: BMI, body mass index; CHL, conductive hearing loss; CT, computed tomography; cVEMPs, cervical vestibular evoked myogenic potentials; IT, intratympanic; MRI, magnetic resonance imaging; SCD, semicircular canal dehiscence; SSNHL, sudden sensorineural hearing loss; WRS, word recognition score ∗ Corresponding author. Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania, 5th Floor Silverstein Building, 3400 Spruce St, Philadelphia, PA, 19104, USA. E-mail address: [email protected] (R.R. Shah). https://doi.org/10.1016/j.xocr.2019.100122 Received 17 November 2018; Received in revised form 4 May 2019; Accepted 22 May 2019 Available online 04 June 2019 2468-5488/ © 2019 Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/).
Otolaryngology Case Reports 12 (2019) 100122
R.R. Shah, et al.
Fig. 1. A: Case 1, pure tone audiometry. Right ear shows moderately severe to severe sensorineural hearing loss. Left ear shows normal hearing sensitivity from 250 Hz to 4 kHz, sloping to a mild sensorineural hearing loss in the high frequencies. B: Case 3, pure tone audiometry. Right ear shows normal hearing sensitivity from 250 Hz to 8 kHz. Left ear shows normal hearing sensitivity from 250 Hz to 6 kHz, sloping to a severe sensorineural hearing loss at 8 kHz.
16% word recognition score (WRS) on the right, and high-frequency SNHL on the left (Fig. 1A). A computed tomography (CT) scan of the temporal bone demonstrated right SCD without other abnormalities (Fig. 2A and B). Vestibular testing was notable for a 52% relative vestibular reduction on the right. Cervical vestibular evoked myogenic potentials (cVEMPs) demonstrated relative reduction of thresholds on the right (85 dBnHL right, 95 dBnHL left). He elected to pursue hearing amplification and deferred surgical intervention for SCD. Case 2: A 27-year-old female presented 5 days after sudden leftsided hearing loss and vertigo. She suffered a motor vehicle collision without clear head trauma about one month prior to presentation. She was started on a 60 mg oral prednisone taper prior to referral without
immediate benefit. Neurotologic exam was normal. Her audiogram showed moderate SNHL in the left ear with a 0% WRS, and normal hearing in the right (Fig. 3A). Intratympanic (IT) dexamethasone was administered to the left ear. An MRI did not reveal any retrocochlear pathology but was suggestive of SCD. Labs consisting of CBC, TSH, ESR, and ANA were normal. Follow up audiogram at 1 week showed 5–10 dB improvement in bone conduction. Because of her nonspecific vestibular symptoms and MRI suggestive of SCD, CT of the temporal bones was ordered, which more clearly demonstrated dehiscence of the left superior semicircular canal (Fig. 2C and D). She underwent 2 additional IT dexamethasone injections and repeat audiograms demonstrated significant improvement in hearing with 92% word recognition scores
2
Otolaryngology Case Reports 12 (2019) 100122
R.R. Shah, et al.
Clinical judgment must be exercised when interpreting CT due to incidental findings of SCD [3]. Nonetheless, these cases raise the possibility that CT may identify possible etiologies of SSNHL that MRI cannot resolve. We obtained CT scans of the temporal bones in the described patients because they had specific findings that suggested a third window effect and SCD. Cases 1 and 3 both reported Tullio phenomenon, and Case 2 reported nonspecific vestibular symptoms with an MRI suggestive of SCD. The question remains as to whether or not there is any association between our patients’ SCD and SSNHL. It is well-recognized that violation of the membranous labyrinth causes deafness and labyrinthitislike symptoms [4]. Given that our patients had symptoms consistent with a labyrinthitis-like event, rupture of the membranous labyrinth in the dehiscent superior canal provides a plausible explanation for the SSNHL. In the setting of SCD, bony dehiscence may occur as a consequence of a traumatic event or chronic pressure from the temporal lobe, resulting in the acute onset of third window symptoms [5,6]. We propose that fracture of this thin bone may also occasionally rupture the membranous labyrinth, thus causing SSNHL in some patients in addition to third-window symptoms. Imaging techniques to improve resolution of the inner ear and membranous labyrinth could potentially provide additional insights to this notion in the future. Although the possibility exists that our patients’ SSNHL was due to an event unrelated to the SCD, their history and workup did not suggest any other etiologies. It is challenging to explain why one patient recovered hearing and the others did not, however. The steroid-responsiveness in Case 2 could have indicated isolated labyrinthitis with coincidental ipsilateral SCD. Alternatively, steroids may have been beneficial due to their effect on local inflammation from a membranous rupture, or perhaps a small membranous rupture may have spontaneously sealed before permanent damage ensued. Case 2 also had normal cVEMPs. One study found that cVEMPs to click stimuli have a sensitivity of 92% and specificity of 97% at 90 dBnHL [7]. However, despite their usefulness, cVEMP thresholds do not always correlate well with symptoms, and it is possible that the area of dehiscence was too small to have reduced cVEMPs [8]. These cases also allude to the challenging management of patients presenting with SSNHL who are found to have SCD. SSNHL is treated with oral and/or IT steroids. However, management of the SCD in this setting is less clear. If the SSNHL was due to a self-sealing rupture of the membranous labyrinth, there may be a risk of future similar episodes that could impact hearing. While surgery for SCD is safe, hearing loss is not currently an indication for repair, and the surgery itself can risk residual hearing [1]. Ultimately, therapeutic decision-making requires discussion between the patient and physician in this unusual scenario. Further investigations looking at the association of SCD and SSNHL may provide deeper understanding of both diagnostic and treatment dilemmas.
Fig. 2. Noncontrast CT of the temporal bones for Cases 1–3. A-B: Case 1, right temporal bone. Pöschl (A) and Stenvers (B) projections demonstrate dehiscence of the right superior semicircular canal (arrows). C-D: Case 2, left temporal bone. Pöschl (C) and Stenvers (D) projections demonstrate dehiscence of the left superior semicircular canal (arrows). E-F: Case 3, left temporal bone. Pöschl (E) and Stenvers (F) projections demonstrate dehiscence of the left superior semicircular canal (arrows).
(Fig. 3B and C). Vestibular testing was normal, and cVEMPs were normal (100 dBnHL bilaterally). Given the return of her hearing, and persistent but tolerable occasional vertigo, the patient elected not to pursue additional treatment. Case 3: A 35-year-old male presented to our clinic 6 years after leftsided sudden hearing loss. His symptoms began after several hours of excessive noise exposure. Accompanying symptoms included ipsilateral aural fullness, tinnitus, dizziness exacerbated by movement, and Tullio phenomenon. Symptoms gradually improved over several months but recurred 2 weeks prior to presentation. Neurotologic exam was normal. His audiogram showed normal hearing from 250 to 6000 Hz on the left sloping to severe loss at 8000 Hz (Fig. 1B), and his vestibular testing was normal. CT of the temporal bone demonstrated a left SCD without other abnormalities (Fig. 2E and F). Cervical VEMPs demonstrated reduced thresholds on the left (55 dBnHL left, 85 dBnHL right). He deferred surgical intervention. Discussion SSNHL associated with SCD has not yet been described. In this report, we describe three patients presenting with SSNHL and concomitant vestibular symptoms with findings highly suspicious for SCD on the side of hearing loss. Workup of SSNHL commonly includes MRI to evaluate for retrocochlear lesions. Conversely, in the workup of SCD, CT scan is favored over MRI as a diagnostic measure. Because of differing imaging modalities, SCD may therefore be overlooked in the setting of SSNHL.
Conclusion We illustrate three cases of patients who presented with SSNHL and findings highly suspicious for SCD on the affected side. These cases add insight into possible etiologies of SSNHL and raise a potential argument for the utility of CT scans in helping to identify unrecognized pathology in the workup of SSNHL.
3
Otolaryngology Case Reports 12 (2019) 100122
R.R. Shah, et al.
Fig. 3. Case 2: Pure tone audiometry. A: Audiometry at time of presentation. Right ear hearing within normal. Left ear shows moderate to moderately severe sensorineural hearing loss. B: Audiometry 3 weeks after intratympanic dexamethasone injection shows improvement to mild to moderate hearing loss in the left ear. C: Audiometry 7 weeks after presentation, following 3 intratympanic dexamethasone injections, shows normal hearing in the left ear.
Conflicts of interest [3]
None.
[4]
Appendix A. Supplementary data
[5]
Supplementary data to this article can be found online at https:// doi.org/10.1016/j.xocr.2019.100122.
[6]
References
[7]
[1] Xie Y, Sharon JD, Pross SE, et al. Surgical complications from superior canal dehiscence syndrome repair: two decades of experience. Otolaryngol Head Neck Surg 2017;157(2):273–80. [2] Patel NS, Hunter JB, O'Connell BP, Bertrand NM, Wanna GB, Carlson ML. Risk of
[8]
4
progressive hearing loss in untreated superior semicircular canal dehiscence. The Laryngoscope 2017;127(5):1181–6. Williamson RA, Vrabec JT, Coker NJ, Sandlin M. Coronal computed tomography prevalence of superior semicircular canal dehiscence. Otolaryngol Head Neck Surg 2003;129(5):481–9. Althaus SR. Spontaneous and traumatic perilymph fistulas. The Laryngoscope 1977;87(3):364–71. Carey JP, Minor LB, Nager GT. Dehiscence or thinning of bone overlying the superior semicircular canal in a temporal bone survey. Arch Otolaryngol Head Neck Surg 2000;126(2):137–47. Minor LB. Labyrinthine fistulae: pathobiology and management. Curr Opin Otolaryngol Head Neck Surg 2003;11(5):340–6. Brantberg K, Verrecchia L. Effectiveness of different click stimuli in diagnosing superior canal dehiscence using cervical vestibular evoked myogenic potentials. Acta Otolaryngol 2012;132(10):1077–83. Hunter JB, O'Connell BP, Wang J, et al. Correlation of superior canal dehiscence surface area with vestibular evoked myogenic potentials, audiometric thresholds, and dizziness handicap. Otol Neurotol 2016;37(8):1104–10.