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Clinical Assessment of Patients with Bilateral Superior Semicircular Canal Dehiscence
Original Article
Clinical Assessment of Patients with Bilateral Superior Semicircular Canal Dehiscence Cheng Hao Jacky Chen1, Thien Nguyen1, Methma Udawatta1, Courtney Duong1, Prasanth Romiyo1, John P. Sheppard1, Quinton Gopen2, Isaac Yang1-7
OBJECTIVE: Superior semicircular canal dehiscence (SSCD) is caused by a deformity in the arcuate eminence, leading to various vestibular and auditory symptoms that can manifest unilaterally or bilaterally. The aim of the present study was to distinguish the differences in symptoms, treatment options, and outcomes between patients with unilateral and bilateral SSCD.
-
METHODS: A retrospective medical record analysis was conducted to identify patients with SSCD treated at a tertiary care center from March 2011 to May 2017. The patient demographic data, preoperative symptom presentation, and postoperative outcomes were extracted. Statistical analyses were performed using IBM SPSS Statistics. Fisher’s exact tests were computed to investigate the relationships between binary variables, with a significance level of P < 0.05.
-
RESULTS: A total of 99 patients with SSCD had been treated at our institution from March 2011 to May 2017. Of these 99 patients, 41 (41.4%) had a diagnosis of bilateral SSCD. Of the 41 patients with bilateral SSCD, 27 (65.9%) were women, and the mean age was 53.6 10.9 years (range, 31.7e73.9). The most common presenting symptom was tinnitus (n [ 33; 80.4%) and dizziness (n [ 33; 80.4%). Previous trauma to the head correlated with a bilateral SSCD presentation (P [ 0.04). Trends were reported between female sex and bilateral SSCD [r(35) [ 0.32379; P [ 0.0506]. Postoperatively, trends were also found, with greater rates of dizziness in patients with bilateral SSCD compared with those with unilateral SSCD (odds ratio, 3.81; P [ 0.0659), and less improvement in dizziness (odds ratio,
-
Key words - Bilateral - Outcomes - Superior semicircular canal dehiscence - Symptomology Abbreviations and Acronyms SSCD: Superior semicircular canal dehiscence VEMP: Vestibular evoked myogenic potential
0.186; P [ 0.0627). No other significant differences were found between the symptoms or clinical outcomes and improvements between the bilateral and unilateral cohorts. CONCLUSION: Bilateral SSCD might result in different clinical symptoms that are more prevalent compared with unilateral SSCD. The findings from the present series of patients with bilateral SSCD suggest that patient symptoms and history are important in the diagnosis of bilateral SSCD and deciding whether 1 or both dehiscences requires surgical intervention.
-
INTRODUCTION
S
uperior semicircular canal dehiscence (SSCD) was first described by Minor et al.1 as a rare osseous deformity in the arcuate eminence, between the middle cranial fossa and the superior semicircular canal, which can manifest unilaterally or bilaterally. This creates a “third mobile window,” along with the oval and round windows, and disrupts fluid flow in the cochlea, leading to various vestibular and auditory symptoms, including internal amplification of sound, tinnitus, autophony, aural fullness, vertigo, dizziness, and oscillopsia.2,3 When combined, these symptoms can severely incapacitate patients in their daily activities, both socially and occupationally. Treatment of SSCD in patients with temperate symptoms can be conservative and includes enduring watchfulness. However, for patients with debilitating symptoms who are unresponsive to conservative measures, a combined neurosurgical and otological approach is required for intervention. Surgical repair of SSCD is achieved by plugging the dehiscence with bone wax, fibrin glue,
5
University of California, Los Angeles, David Geffen School of Medicine, Los Angeles, California, USA; Department of 6Neurosurgery and 7Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance, California, USA To whom correspondence should be addressed: Isaac Yang, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2019). https://doi.org/10.1016/j.wneu.2019.03.205 Journal homepage: www.journals.elsevier.com/world-neurosurgery Available online: www.sciencedirect.com
From the Departments of 1Neurosurgery, 2Head and Neck Surgery, 3Radiation Oncology, and 4 Jonsson Comprehensive Cancer Center, Ronald Reagan UCLA Medical Center, and
WORLD NEUROSURGERY -: e1-e4, - 2019
1878-8750/$ - see front matter ª 2019 Elsevier Inc. All rights reserved.
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ORIGINAL ARTICLE CHENG HAO JACKY CHEN ET AL.
TRENDS IN BILATERAL SUPERIOR SEMICIRCULAR CANAL DEHISCENCE
autologous bone, and collagen sponge using a middle cranial fossa or transmastoid approach.4 Although studies of patients with bilateral SSCD have been previously reported, the symptoms, treatment options, and outcomes remain unclear.5-7 The present clinical study aimed to distinguish the differences in symptoms, treatment options, and outcomes of patients with bilateral SSCD from those with unilateral patients.
Table 1. Baseline Characteristics, Presenting Symptoms, and Follow-Up Data for Patients With Superior Semicircular Canal Dehiscence Characteristic All patients
Range
Study Design A retrospective study of patients with diagnosed unilateral and bilateral SSCD who had undergone surgical repair via a middle cranial fossa craniotomy at a single institution. The institutional review board approved the present study, and all patient identifiers were removed. Patient Selection The patients in the present retrospective study included patients with diagnosed SSCD who had undergone surgery by the senior authors (I.Y. and Q.G.) at the Ronald Reagan UCLA Medical Center from March 2011 to May 2017. The diagnosis of SSCD was determined from the findings from audiometry, provocative testing, vestibular evoked myogenic potential (VEMP) testing, and high-resolution computed tomography of the temporal bone to differentiate SSCD from Meniere’s disease. Patients with a confirmed diagnosis were only recommended surgery when conservative measures, such as trigger avoidance, had been exhausted and were no longer effective in mitigating symptoms. Patients with a diagnosis of bilateral SSCD were included in the bilateral cohort, and had undergone surgery to repair 1 dehiscence or both.
Statistical Analysis Statistical analyses were performed using IBM SPSS Statistics (IBM Corp., Armonk, New York, New York, USA). The Fisher exact test was used to investigate relationships between binary variables such as symptom presence or absence, with the significance level set at P < 0.05. Trends were reported if the P value was >0.1 but
e2
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52.35 12.79 20.77e84.32
Sex Female
64 (64.65)
Male
35 (35.35)
Presenting symptoms Auditory Autophony
69 (69.70)
Tinnitus
78 (78.79)
Amplification*
53 (53.54)
Aural fullness
45 (45.45)
Hearing loss
48 (48.48)
Hyperacusis
24 (24.24)
Vestibular Dizziness
71 (71.72)
Disequilibrium
51 (51.52)
Vertigo
23 (23.23)
Oscillopsia
12 (12.12)
Headache
Data Collection The patient history and demographic data were obtained from the electronic medical records (Table 1). The symptoms at presentation and the postoperative outcomes were obtained from a review of the progress notes and were coded in a binary fashion as either symptom presence or absence. These included autophony, internal amplification of sound, aural fullness, tinnitus, hyperacusis, hearing loss, vertigo, dizziness, disequilibrium, oscillopsia, and headache. Symptom improvement or decline was noted if the corresponding symptom had been surgically eliminated or worsened, respectively. Patients with a diagnosis of bilateral SSCD were included in the bilateral cohort and had either undergone 1 surgery for unilateral repair or 2 separate procedures for bilateral repair. Patients with incomplete medical records were excluded from the corresponding analyses to prevent assumptions regarding the symptoms and outcomes.
99
Age (years) Mean SD
METHODS
n (%)
19 (19.19)
Surgery to follow-up (months) Mean SD Range
7.40 10.69 0.03e59.53
SD, standard deviation. *Internal amplification of sound.
<0.05. Point biserial correlations were calculated for comparisons between the continuous and binary variables.
RESULTS A total of 99 patients (64 women; 64.6%) had undergone surgical intervention for SSCD at our institution from March 2011 to May 2017. Of the 99 patients, 41 (41.4%) had a diagnosis of bilateral SSCD, for unilateral/bilateral ratio of 1.39:1. In the bilateral cohort, 27 patients (65.9%) were women, and the mean age was 53.6 10.9 years (range, 31.7e73.9). Of the 41 patients, 11 (26.8%) had undergone a second surgery for treatment of bilateral dehiscences. The most common presenting symptom was tinnitus (n ¼ 33; 80.4%) and dizziness (n ¼ 33; 80.4%), followed by autophony (n ¼ 31; 75.6%), internal amplification of sound (n ¼ 26; 634%), disequilibrium (n ¼ 23; 56.1%), aural fullness (n ¼ 19; 46.3%), and
WORLD NEUROSURGERY, https://doi.org/10.1016/j.wneu.2019.03.205
ORIGINAL ARTICLE CHENG HAO JACKY CHEN ET AL.
TRENDS IN BILATERAL SUPERIOR SEMICIRCULAR CANAL DEHISCENCE
hearing loss (n ¼ 18; 43.9%). During the follow-up period, the greatest rates of improvement were seen with tinnitus (n ¼ 10; 24.4%), followed by autophony (n ¼ 6; 14.6%), and internal amplification of sound (n ¼ 4; 9.75%). Two patients (4.87%) experienced a decline in dizziness after surgery, and 1 patient (2.44%) experienced a decline in hearing loss. No wound infections, hematomas, or epileptic episodes were reported. A history of trauma to the head at presentation correlated with the diagnosis of bilateral SSCD (P ¼ 0.04). Trends were found between sex and bilateral SSCD, with more women presenting with bilateral SSCD compared with men [r(35) ¼ 0.32379; P ¼ 0.0506)]. Trends were also shown between vertigo at the initial presentation and the need for a second surgery for bilateral SSCD repair (odds ratio, 3.00; P ¼ 0.083). Postoperatively, we found trends showing greater rates of dizziness in patients with bilateral SSCD compared with those with unilateral SSCD (odds ratio, 3.81; P ¼ 0.0659), and less improvement in dizziness (odds ratio, 0.186; P ¼ 0.0627). Aside from these trends, no significant differences were shown between the symptoms at presentation or clinical outcomes and improvement between the bilateral cohort and the unilateral cohort. Similarly, no significant differences were found in symptom improvement in the cohort of patients undergoing bilateral SSCD surgery between the first postoperative period and the second postoperative period. DISCUSSION In 1998, Minor et al.1 first described SSCD in a cohort of patients presenting with sound- and/or pressure-induced vertigo due to a thinning or dehiscence of the superior semicircular canal. This created an additional opening from the middle to inner ear, resulting in loss of acoustic energy and abnormal stimulation of the vestibular system and leading to characteristic symptoms described in patients with SSCD.8-11 Although SSCD originates as an otological defect, surgical intervention for patients with SSCD experiencing debilitating symptoms involves either a middle cranial fossa or transmastoid craniotomy and is, thus, duly recognized as a neurosurgical problem. The diagnosis of SSCD is predominantly determined by the presentation of clinical symptoms, high-resolution computed tomography findings of the temporal bone, and VEMP testing. It was previously reported that patients with bilateral SSCD presented with more enhanced VEMP potentials and reduced thresholds and that VEMP was important in determining the clinically worse ear in patients with bilateral SSCD, with a lower VEMP threshold in the worse ear compared with the contralateral ear.12,13 Although patients with unilateral SSCD can present with an array of symptoms, including sound- and pressure-induced vertigo
REFERENCES 1. Minor LB, Solomon D, Zinreich JS, Zee DS. Sound- and/or pressure-induced vertigo due to bone dehiscence of the superior semicircular canal. Arch Otolaryngol Head Neck Surg. 1998;124: 249-258.
(Tullio phenomenon and Hennebert sign), disequilibrium, tinnitus, oscillopsia, dizziness, and internal amplification of sound, certain presenting symptoms have been reported specifically in patients with bilateral SSCD.1-3,14 These symptoms included vertical oscillopsia, impaired vision during movement, gait unsteadiness, and jerk vertical and torsional nystagmus.15,16 In 2012, Agrawal et al.17 reported the cases of 5 patients with bilateral SSCD who had undergone bilateral surgery for dehiscence repair. Of the 5 patients, 3 reported that contralateral symptoms persisted after the first surgery, leading to the decision to undergo a second surgical dehiscence repair. This was also shown in the present series, in which a trend was seen between greater rates of dizziness in patients with bilateral SSCD after the first surgical repair. The group also noted that various degrees of oscillopsia had developed postoperatively in all patients. However, the postoperative symptom was still preferable to the preoperative disabilities. Thus, a second bilateral surgery was recommended only if the contralateral symptoms had persisted after the first surgery. In the present study, no significant difference was found in symptom improvement between the first and second postoperative periods. In the present series, patients presenting with a history of trauma to the head correlated with a diagnosis of bilateral SSCD. A “2-hit” mechanism of disease has previously been described, in which the “first hit” is a congenital underdevelopment of the bone overlying the superior semicircular canal, resulting in thinning or dehiscence of the bone. This will predispose the patient to the “second hit,” which can include trauma to the head, resulting in complete dehiscence of the thin bone.18,19 Study Limitations The present study was limited by the small sample size from a single institution, which resulted from the rarity of the described disease. Also, the characterization of the presenting symptoms and symptom improvement or decline postoperatively was not described for all the patients, further reducing the number of cases available for analysis. In future studies, multi-institutional data should be used to increase the sample size and specific pre- and postoperative surveys to illustrate the specific symptoms of SSCD should be administered to patients. CONCLUSION Bilateral SSCD could have different clinical symptoms that are more prevalent than in unilateral SSCD. The findings from the present series of patients with bilateral SSCD suggests that patients’ symptoms and history are important in the diagnosis of bilateral SSCD and determining whether 1 or both dehiscences requires surgical intervention.
2. Lagman C, Ong V, Chung LK, et al. Pediatric superior semicircular canal dehiscence: illustrative case and systematic review. J Neurosurg Pediatr. 2017;20:196-203. 3. Ung N, Chung LK, Lagman C, et al. Outcomes of middle fossa craniotomy for the repair of superior
WORLD NEUROSURGERY -: e1-e4, - 2019
semicircular canal dehiscence. J Clin Neurosci. 2017; 43:103-107. 4. Nguyen T, Lagman C, Sheppard JP, et al. Middle cranial fossa approach for the repair of superior semicircular canal dehiscence is associated with greater symptom resolution compared to
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ORIGINAL ARTICLE CHENG HAO JACKY CHEN ET AL.
transmastoid approach. Acta Neurochir (Wien). 2018;160:1219-1224. 5. Hamid MA. Bilateral dehiscence of the superior semicircular canals. Otol Neurotol. 2001;22:567-568. 6. Kanaan AA, Raad RA, Hourani RG, Zaytoun GM. Bilateral superior semicircular canal dehiscence in a child with sensorineural hearing loss and without vestibular symptoms. Int J Pediatr Otorhinolaryngol. 2011;75:877-879. 7. Manzari L, Modugno GC. Bilateral dehiscence of both superior and posterior semicircular canals. Otol Neurotol. 2009;30:423-425. 8. Amoodi HA, Makki FM, McNeil M, Bance M. Transmastoid resurfacing of superior semicircular canal dehiscence. Laryngoscope. 2011;121:1117-1123. 9. Friedland DR, Michel MA. Cranial thickness in superior canal dehiscence syndrome: implications for canal resurfacing surgery. Otol Neurotol. 2006; 27:346-354.
TRENDS IN BILATERAL SUPERIOR SEMICIRCULAR CANAL DEHISCENCE
12. Manzari L, Burgess AM, MacDougall HG, Curthoys IS. Enhanced otolithic function in semicircular canal dehiscence. Acta Otolaryngol. 2011;131:107-112.
19. Peng KA, Ahmed S, Yang I, Gopen Q. Temporal bone fracture causing superior semicircular canal dehiscence. Case Rep Otolaryngol. 2014;2014:817291.
13. Niesten ME, McKenna MJ, Herrmann BS, Grolman W, Lee DJ. Utility of cVEMPs in bilateral superior canal dehiscence syndrome. Laryngoscope. 2013;123:226-232.
Conflict of interest statement: Thien Nguyen, Methma Udawatta, and John P. Sheppard are recipients of the David Geffen Medical Scholarship. Prasanth Romiyo is supported by the Tina and Fred Segal Benign Brain Tumor and Skull Base Research Fellowship, AUA Carolyn L. Kuckein Student Research Fellowship, and Neurosurgery Research & Education Foundation Medical Student Grant. Isaac Yang is supported by the UCLA Visionary Ball Fund Grant, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research UCLA Scholars in Translational Medicine Program Award, Jason Dessel Memorial Seed Grant, UCLA Honberger Endowment Brain Tumor Research Seed Grant, and Stop Cancer (US) Development Award. The sponsors had no role in the design or conduct of the present study. The remaining authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
14. Minor LB, Cremer PD, Carey JP, Della Santina CC, Streubel SO, Weg N. Symptoms and signs in superior canal dehiscence syndrome. Ann N Y Acad Sci. 2001;942:259-273. 15. Deutschlander A, Strupp M, Jahn K, Jager L, Quiring F, Brandt T. Vertical oscillopsia in bilateral superior canal dehiscence syndrome. Neurology. 2004;62:784-787. 16. Tilikete C, Krolak-Salmon P, Truy E, Vighetto A. Pulse-synchronous eye oscillations revealing bone superior canal dehiscence. Ann Neurol. 2004;56: 556-560.
Received 25 September 2018; accepted 20 March 2019
10. Minor LB, Carey JP, Cremer PD, Lustig LR, Streubel SO, Ruckenstein MJ. Dehiscence of bone overlying the superior canal as a cause of apparent conductive hearing loss. Otol Neurotol. 2003;24: 270-278.
17. Agrawal Y, Minor LB, Schubert MC, Janky KL, Davalos-Bichara M, Carey JP. Second-side surgery in superior canal dehiscence syndrome. Otol Neurotol. 2012;33:72-77.
Citation: World Neurosurg. (2019). https://doi.org/10.1016/j.wneu.2019.03.205
11. Yew A, Zarinkhou G, Spasic M, Trang A, Gopen Q, Yang I. Characteristics and management of superior semicircular canal dehiscence. J Neurol Surg B Skull Base. 2012;73:365-370.
18. 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;126:137-147.
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WORLD NEUROSURGERY, https://doi.org/10.1016/j.wneu.2019.03.205
Clinical Assessment of Patients with Bilateral Superior Semicircular Canal Dehiscence Cheng Hao Jacky Chen1, Thien Nguyen1, Methma Udawatta1, Courtney Duong1, Prasanth Romiyo1, John P. Sheppard1, Quinton Gopen2, Isaac Yang1-7
OBJECTIVE: Superior semicircular canal dehiscence (SSCD) is caused by a deformity in the arcuate eminence, leading to various vestibular and auditory symptoms that can manifest unilaterally or bilaterally. The aim of the present study was to distinguish the differences in symptoms, treatment options, and outcomes between patients with unilateral and bilateral SSCD.
-
METHODS: A retrospective medical record analysis was conducted to identify patients with SSCD treated at a tertiary care center from March 2011 to May 2017. The patient demographic data, preoperative symptom presentation, and postoperative outcomes were extracted. Statistical analyses were performed using IBM SPSS Statistics. Fisher’s exact tests were computed to investigate the relationships between binary variables, with a significance level of P < 0.05.
-
RESULTS: A total of 99 patients with SSCD had been treated at our institution from March 2011 to May 2017. Of these 99 patients, 41 (41.4%) had a diagnosis of bilateral SSCD. Of the 41 patients with bilateral SSCD, 27 (65.9%) were women, and the mean age was 53.6 10.9 years (range, 31.7e73.9). The most common presenting symptom was tinnitus (n [ 33; 80.4%) and dizziness (n [ 33; 80.4%). Previous trauma to the head correlated with a bilateral SSCD presentation (P [ 0.04). Trends were reported between female sex and bilateral SSCD [r(35) [ 0.32379; P [ 0.0506]. Postoperatively, trends were also found, with greater rates of dizziness in patients with bilateral SSCD compared with those with unilateral SSCD (odds ratio, 3.81; P [ 0.0659), and less improvement in dizziness (odds ratio,
-
Key words - Bilateral - Outcomes - Superior semicircular canal dehiscence - Symptomology Abbreviations and Acronyms SSCD: Superior semicircular canal dehiscence VEMP: Vestibular evoked myogenic potential
0.186; P [ 0.0627). No other significant differences were found between the symptoms or clinical outcomes and improvements between the bilateral and unilateral cohorts. CONCLUSION: Bilateral SSCD might result in different clinical symptoms that are more prevalent compared with unilateral SSCD. The findings from the present series of patients with bilateral SSCD suggest that patient symptoms and history are important in the diagnosis of bilateral SSCD and deciding whether 1 or both dehiscences requires surgical intervention.
-
INTRODUCTION
S
uperior semicircular canal dehiscence (SSCD) was first described by Minor et al.1 as a rare osseous deformity in the arcuate eminence, between the middle cranial fossa and the superior semicircular canal, which can manifest unilaterally or bilaterally. This creates a “third mobile window,” along with the oval and round windows, and disrupts fluid flow in the cochlea, leading to various vestibular and auditory symptoms, including internal amplification of sound, tinnitus, autophony, aural fullness, vertigo, dizziness, and oscillopsia.2,3 When combined, these symptoms can severely incapacitate patients in their daily activities, both socially and occupationally. Treatment of SSCD in patients with temperate symptoms can be conservative and includes enduring watchfulness. However, for patients with debilitating symptoms who are unresponsive to conservative measures, a combined neurosurgical and otological approach is required for intervention. Surgical repair of SSCD is achieved by plugging the dehiscence with bone wax, fibrin glue,
5
University of California, Los Angeles, David Geffen School of Medicine, Los Angeles, California, USA; Department of 6Neurosurgery and 7Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance, California, USA To whom correspondence should be addressed: Isaac Yang, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2019). https://doi.org/10.1016/j.wneu.2019.03.205 Journal homepage: www.journals.elsevier.com/world-neurosurgery Available online: www.sciencedirect.com
From the Departments of 1Neurosurgery, 2Head and Neck Surgery, 3Radiation Oncology, and 4 Jonsson Comprehensive Cancer Center, Ronald Reagan UCLA Medical Center, and
WORLD NEUROSURGERY -: e1-e4, - 2019
1878-8750/$ - see front matter ª 2019 Elsevier Inc. All rights reserved.
www.journals.elsevier.com/world-neurosurgery
e1
ORIGINAL ARTICLE CHENG HAO JACKY CHEN ET AL.
TRENDS IN BILATERAL SUPERIOR SEMICIRCULAR CANAL DEHISCENCE
autologous bone, and collagen sponge using a middle cranial fossa or transmastoid approach.4 Although studies of patients with bilateral SSCD have been previously reported, the symptoms, treatment options, and outcomes remain unclear.5-7 The present clinical study aimed to distinguish the differences in symptoms, treatment options, and outcomes of patients with bilateral SSCD from those with unilateral patients.
Table 1. Baseline Characteristics, Presenting Symptoms, and Follow-Up Data for Patients With Superior Semicircular Canal Dehiscence Characteristic All patients
Range
Study Design A retrospective study of patients with diagnosed unilateral and bilateral SSCD who had undergone surgical repair via a middle cranial fossa craniotomy at a single institution. The institutional review board approved the present study, and all patient identifiers were removed. Patient Selection The patients in the present retrospective study included patients with diagnosed SSCD who had undergone surgery by the senior authors (I.Y. and Q.G.) at the Ronald Reagan UCLA Medical Center from March 2011 to May 2017. The diagnosis of SSCD was determined from the findings from audiometry, provocative testing, vestibular evoked myogenic potential (VEMP) testing, and high-resolution computed tomography of the temporal bone to differentiate SSCD from Meniere’s disease. Patients with a confirmed diagnosis were only recommended surgery when conservative measures, such as trigger avoidance, had been exhausted and were no longer effective in mitigating symptoms. Patients with a diagnosis of bilateral SSCD were included in the bilateral cohort, and had undergone surgery to repair 1 dehiscence or both.
Statistical Analysis Statistical analyses were performed using IBM SPSS Statistics (IBM Corp., Armonk, New York, New York, USA). The Fisher exact test was used to investigate relationships between binary variables such as symptom presence or absence, with the significance level set at P < 0.05. Trends were reported if the P value was >0.1 but
e2
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52.35 12.79 20.77e84.32
Sex Female
64 (64.65)
Male
35 (35.35)
Presenting symptoms Auditory Autophony
69 (69.70)
Tinnitus
78 (78.79)
Amplification*
53 (53.54)
Aural fullness
45 (45.45)
Hearing loss
48 (48.48)
Hyperacusis
24 (24.24)
Vestibular Dizziness
71 (71.72)
Disequilibrium
51 (51.52)
Vertigo
23 (23.23)
Oscillopsia
12 (12.12)
Headache
Data Collection The patient history and demographic data were obtained from the electronic medical records (Table 1). The symptoms at presentation and the postoperative outcomes were obtained from a review of the progress notes and were coded in a binary fashion as either symptom presence or absence. These included autophony, internal amplification of sound, aural fullness, tinnitus, hyperacusis, hearing loss, vertigo, dizziness, disequilibrium, oscillopsia, and headache. Symptom improvement or decline was noted if the corresponding symptom had been surgically eliminated or worsened, respectively. Patients with a diagnosis of bilateral SSCD were included in the bilateral cohort and had either undergone 1 surgery for unilateral repair or 2 separate procedures for bilateral repair. Patients with incomplete medical records were excluded from the corresponding analyses to prevent assumptions regarding the symptoms and outcomes.
99
Age (years) Mean SD
METHODS
n (%)
19 (19.19)
Surgery to follow-up (months) Mean SD Range
7.40 10.69 0.03e59.53
SD, standard deviation. *Internal amplification of sound.
<0.05. Point biserial correlations were calculated for comparisons between the continuous and binary variables.
RESULTS A total of 99 patients (64 women; 64.6%) had undergone surgical intervention for SSCD at our institution from March 2011 to May 2017. Of the 99 patients, 41 (41.4%) had a diagnosis of bilateral SSCD, for unilateral/bilateral ratio of 1.39:1. In the bilateral cohort, 27 patients (65.9%) were women, and the mean age was 53.6 10.9 years (range, 31.7e73.9). Of the 41 patients, 11 (26.8%) had undergone a second surgery for treatment of bilateral dehiscences. The most common presenting symptom was tinnitus (n ¼ 33; 80.4%) and dizziness (n ¼ 33; 80.4%), followed by autophony (n ¼ 31; 75.6%), internal amplification of sound (n ¼ 26; 634%), disequilibrium (n ¼ 23; 56.1%), aural fullness (n ¼ 19; 46.3%), and
WORLD NEUROSURGERY, https://doi.org/10.1016/j.wneu.2019.03.205
ORIGINAL ARTICLE CHENG HAO JACKY CHEN ET AL.
TRENDS IN BILATERAL SUPERIOR SEMICIRCULAR CANAL DEHISCENCE
hearing loss (n ¼ 18; 43.9%). During the follow-up period, the greatest rates of improvement were seen with tinnitus (n ¼ 10; 24.4%), followed by autophony (n ¼ 6; 14.6%), and internal amplification of sound (n ¼ 4; 9.75%). Two patients (4.87%) experienced a decline in dizziness after surgery, and 1 patient (2.44%) experienced a decline in hearing loss. No wound infections, hematomas, or epileptic episodes were reported. A history of trauma to the head at presentation correlated with the diagnosis of bilateral SSCD (P ¼ 0.04). Trends were found between sex and bilateral SSCD, with more women presenting with bilateral SSCD compared with men [r(35) ¼ 0.32379; P ¼ 0.0506)]. Trends were also shown between vertigo at the initial presentation and the need for a second surgery for bilateral SSCD repair (odds ratio, 3.00; P ¼ 0.083). Postoperatively, we found trends showing greater rates of dizziness in patients with bilateral SSCD compared with those with unilateral SSCD (odds ratio, 3.81; P ¼ 0.0659), and less improvement in dizziness (odds ratio, 0.186; P ¼ 0.0627). Aside from these trends, no significant differences were shown between the symptoms at presentation or clinical outcomes and improvement between the bilateral cohort and the unilateral cohort. Similarly, no significant differences were found in symptom improvement in the cohort of patients undergoing bilateral SSCD surgery between the first postoperative period and the second postoperative period. DISCUSSION In 1998, Minor et al.1 first described SSCD in a cohort of patients presenting with sound- and/or pressure-induced vertigo due to a thinning or dehiscence of the superior semicircular canal. This created an additional opening from the middle to inner ear, resulting in loss of acoustic energy and abnormal stimulation of the vestibular system and leading to characteristic symptoms described in patients with SSCD.8-11 Although SSCD originates as an otological defect, surgical intervention for patients with SSCD experiencing debilitating symptoms involves either a middle cranial fossa or transmastoid craniotomy and is, thus, duly recognized as a neurosurgical problem. The diagnosis of SSCD is predominantly determined by the presentation of clinical symptoms, high-resolution computed tomography findings of the temporal bone, and VEMP testing. It was previously reported that patients with bilateral SSCD presented with more enhanced VEMP potentials and reduced thresholds and that VEMP was important in determining the clinically worse ear in patients with bilateral SSCD, with a lower VEMP threshold in the worse ear compared with the contralateral ear.12,13 Although patients with unilateral SSCD can present with an array of symptoms, including sound- and pressure-induced vertigo
REFERENCES 1. Minor LB, Solomon D, Zinreich JS, Zee DS. Sound- and/or pressure-induced vertigo due to bone dehiscence of the superior semicircular canal. Arch Otolaryngol Head Neck Surg. 1998;124: 249-258.
(Tullio phenomenon and Hennebert sign), disequilibrium, tinnitus, oscillopsia, dizziness, and internal amplification of sound, certain presenting symptoms have been reported specifically in patients with bilateral SSCD.1-3,14 These symptoms included vertical oscillopsia, impaired vision during movement, gait unsteadiness, and jerk vertical and torsional nystagmus.15,16 In 2012, Agrawal et al.17 reported the cases of 5 patients with bilateral SSCD who had undergone bilateral surgery for dehiscence repair. Of the 5 patients, 3 reported that contralateral symptoms persisted after the first surgery, leading to the decision to undergo a second surgical dehiscence repair. This was also shown in the present series, in which a trend was seen between greater rates of dizziness in patients with bilateral SSCD after the first surgical repair. The group also noted that various degrees of oscillopsia had developed postoperatively in all patients. However, the postoperative symptom was still preferable to the preoperative disabilities. Thus, a second bilateral surgery was recommended only if the contralateral symptoms had persisted after the first surgery. In the present study, no significant difference was found in symptom improvement between the first and second postoperative periods. In the present series, patients presenting with a history of trauma to the head correlated with a diagnosis of bilateral SSCD. A “2-hit” mechanism of disease has previously been described, in which the “first hit” is a congenital underdevelopment of the bone overlying the superior semicircular canal, resulting in thinning or dehiscence of the bone. This will predispose the patient to the “second hit,” which can include trauma to the head, resulting in complete dehiscence of the thin bone.18,19 Study Limitations The present study was limited by the small sample size from a single institution, which resulted from the rarity of the described disease. Also, the characterization of the presenting symptoms and symptom improvement or decline postoperatively was not described for all the patients, further reducing the number of cases available for analysis. In future studies, multi-institutional data should be used to increase the sample size and specific pre- and postoperative surveys to illustrate the specific symptoms of SSCD should be administered to patients. CONCLUSION Bilateral SSCD could have different clinical symptoms that are more prevalent than in unilateral SSCD. The findings from the present series of patients with bilateral SSCD suggests that patients’ symptoms and history are important in the diagnosis of bilateral SSCD and determining whether 1 or both dehiscences requires surgical intervention.
2. Lagman C, Ong V, Chung LK, et al. Pediatric superior semicircular canal dehiscence: illustrative case and systematic review. J Neurosurg Pediatr. 2017;20:196-203. 3. Ung N, Chung LK, Lagman C, et al. Outcomes of middle fossa craniotomy for the repair of superior
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semicircular canal dehiscence. J Clin Neurosci. 2017; 43:103-107. 4. Nguyen T, Lagman C, Sheppard JP, et al. Middle cranial fossa approach for the repair of superior semicircular canal dehiscence is associated with greater symptom resolution compared to
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transmastoid approach. Acta Neurochir (Wien). 2018;160:1219-1224. 5. Hamid MA. Bilateral dehiscence of the superior semicircular canals. Otol Neurotol. 2001;22:567-568. 6. Kanaan AA, Raad RA, Hourani RG, Zaytoun GM. Bilateral superior semicircular canal dehiscence in a child with sensorineural hearing loss and without vestibular symptoms. Int J Pediatr Otorhinolaryngol. 2011;75:877-879. 7. Manzari L, Modugno GC. Bilateral dehiscence of both superior and posterior semicircular canals. Otol Neurotol. 2009;30:423-425. 8. Amoodi HA, Makki FM, McNeil M, Bance M. Transmastoid resurfacing of superior semicircular canal dehiscence. Laryngoscope. 2011;121:1117-1123. 9. Friedland DR, Michel MA. Cranial thickness in superior canal dehiscence syndrome: implications for canal resurfacing surgery. Otol Neurotol. 2006; 27:346-354.
TRENDS IN BILATERAL SUPERIOR SEMICIRCULAR CANAL DEHISCENCE
12. Manzari L, Burgess AM, MacDougall HG, Curthoys IS. Enhanced otolithic function in semicircular canal dehiscence. Acta Otolaryngol. 2011;131:107-112.
19. Peng KA, Ahmed S, Yang I, Gopen Q. Temporal bone fracture causing superior semicircular canal dehiscence. Case Rep Otolaryngol. 2014;2014:817291.
13. Niesten ME, McKenna MJ, Herrmann BS, Grolman W, Lee DJ. Utility of cVEMPs in bilateral superior canal dehiscence syndrome. Laryngoscope. 2013;123:226-232.
Conflict of interest statement: Thien Nguyen, Methma Udawatta, and John P. Sheppard are recipients of the David Geffen Medical Scholarship. Prasanth Romiyo is supported by the Tina and Fred Segal Benign Brain Tumor and Skull Base Research Fellowship, AUA Carolyn L. Kuckein Student Research Fellowship, and Neurosurgery Research & Education Foundation Medical Student Grant. Isaac Yang is supported by the UCLA Visionary Ball Fund Grant, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research UCLA Scholars in Translational Medicine Program Award, Jason Dessel Memorial Seed Grant, UCLA Honberger Endowment Brain Tumor Research Seed Grant, and Stop Cancer (US) Development Award. The sponsors had no role in the design or conduct of the present study. The remaining authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
14. Minor LB, Cremer PD, Carey JP, Della Santina CC, Streubel SO, Weg N. Symptoms and signs in superior canal dehiscence syndrome. Ann N Y Acad Sci. 2001;942:259-273. 15. Deutschlander A, Strupp M, Jahn K, Jager L, Quiring F, Brandt T. Vertical oscillopsia in bilateral superior canal dehiscence syndrome. Neurology. 2004;62:784-787. 16. Tilikete C, Krolak-Salmon P, Truy E, Vighetto A. Pulse-synchronous eye oscillations revealing bone superior canal dehiscence. Ann Neurol. 2004;56: 556-560.
Received 25 September 2018; accepted 20 March 2019
10. Minor LB, Carey JP, Cremer PD, Lustig LR, Streubel SO, Ruckenstein MJ. Dehiscence of bone overlying the superior canal as a cause of apparent conductive hearing loss. Otol Neurotol. 2003;24: 270-278.
17. Agrawal Y, Minor LB, Schubert MC, Janky KL, Davalos-Bichara M, Carey JP. Second-side surgery in superior canal dehiscence syndrome. Otol Neurotol. 2012;33:72-77.
Citation: World Neurosurg. (2019). https://doi.org/10.1016/j.wneu.2019.03.205
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18. 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;126:137-147.
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