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Isaac Yang - One of the best experts on this subject based on the ideXlab platform.
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incidence of intraoperative hearing loss during middle cranial fossa approach for repair of superior semicircular canal dehiscence
Journal of Clinical Neuroscience, 2018Co-Authors: Michael Johanis, Isaac Yang, Quinton GopenAbstract:Abstract Introduction Superior semicircular canal dehiscence is a rare inner ear disorder characterized by an abnormal third opening between the superior semicircular canal and middle fossa. Symptoms include amplification of internal sounds, aural fullness, tinnitus, hearing loss, Autophony, sound-induced vertigo (Tullio phenomenon), pressure-induced vertigo (Hennebert sign), disequilibrium, nystagmus, oscillopsia, and headache. While no cure exists for SSCD, surgical treatment has proven to effectively minimize these symptoms. This study reviewed brainstem auditory evoked potentials (BAEPs) that were monitored intraoperatively to better understand hearing loss risks associated with surgical treatment for SSCD. Methods A retrospective chart review was conducted at the University of California, Los Angeles on adult patients with a confirmed diagnosis of SSCD who had undergone a middle cranial fossa repair from March 2011 to October 2017. A total of 142 cases of SSCD in 118 patients were repaired. Results The majority of patients’ BAEPs remained stable and had no intraoperative hearing changes (n = 135; 95.1%). Seven patients experienced intraoperative changes as determined by a prolongation and reduction of Wave V latency (4.9%). Of these seven cases, five experienced a return to baseline prior to the end of surgery, and had no post-operative changes in hearing (71.4%). Overall, only two of the 142 surgeries (1.4%) resulted in failure to normalize and, as such, these patients experienced permanent changes in hearing. Conclusion The results of this retrospective review demonstrate a low risk for hearing loss due to SSCD surgery via the middle fossa craniotomy approach.
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outcomes of middle fossa craniotomy for the repair of superior semicircular canal dehiscence
Journal of Clinical Neuroscience, 2017Co-Authors: Nolan Ung, Quinton Gopen, Lawrance K Chung, Carlito Lagman, Nikhilesh S Bhatt, Natalie E Barnette, Vera Ong, Isaac YangAbstract:Abstract Superior semicircular canal dehiscence (SSCD) is a rare defect of the arcuate eminence that causes an abnormal connection between the superior semicircular canal and middle cranial fossa. Patients often present with a variety of auditory and vestibular symptoms. Trigger avoidance is the initial strategy, but surgery may be necessary in debilitating cases. We retrospectively reviewed SSCD patients undergoing repair via a middle fossa craniotomy between March 2011 and September 2015. Forty-nine patients undergoing 58 surgeries were identified. Autophony was the most common symptom at presentation (n = 44; 90%). Mean follow-up was 10.9 months, with 100% of patients reporting resolution of at least one symptom. Aural fullness was the most commonly resolved symptom following surgical repair (n = 19/22; 86%). Hearing loss (n = 11/25; 44%) and tinnitus (n = 11/38; 29%) were the most common symptoms to persist following surgery. The most common symptom to develop after surgery was disequilibrium (n = 4/18; 22%). Upon comparing the overall pre-operative and post-operative groups, the number of patients with Autophony (p
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minimally invasive middle fossa keyhole craniectomy for repair of superior semicircular canal dehiscence
Operative Neurosurgery, 2017Co-Authors: Vanessa Trieu, Quinton Gopen, Marko Spasic, Lawrance K Chung, Nolan Ung, Panayiotis Pelargos, Brittany L Voth, Isaac YangAbstract:Background Superior semicircular canal dehiscence (SSCD) presents with varying degrees of auditory and vestibular dysfunction. The condition is confirmed on high-resolution computed tomography (CT) imaging, and symptoms are often improved by surgical repair. Although a classic middle fossa craniotomy has been used with good results, recent advances in technique have allowed for modification of the traditional approach into a smaller skin incision and a minimally invasive middle fossa keyhole craniectomy roughly 1.7 cm in diameter. Objective To delineate this novel approach and describe the technique for accurate localization of the dehiscence using preoperative measurements and intraoperative image guidance, thereby minimizing the need for a larger skin incision and craniotomy. Methods Patients were independently diagnosed with SSCD by the senior authors. Once relevant imaging was acquired, the novel keyhole technique was performed. Patients' vestibular and auditory symptoms before and after the procedure were assessed. Outcomes from a series of patients treated with this keyhole approach were tabulated and reported. Results Twelve cases from 11 patients were included in this series. Auditory symptoms had high rates of resolution with pulsatile tinnitus, internal amplification of sounds, and Autophony being resolved in a majority of cases. Only 2 cases reported hearing decline. Sound/pressure induced vertigo and disequilibrium also demonstrated high rates of resolution. No complications were reported. Conclusion The minimally invasive middle fossa keyhole craniectomy is a novel approach for the repair of SSCD. This approach may contribute to resolved auditory and vestibular symptoms with low morbidity and quick recovery.
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Case Report Temporal Bone Fracture Causing Superior Semicircular Canal Dehiscence
2016Co-Authors: Kevin A Peng, Isaac Yang, Sameer Ahmed, Quinton GopenAbstract:which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Importance. Superior semicircular canal dehiscence (SCD) is a third window lesion of the inner ear causing symptoms of vertigo, Autophony, tinnitus, and hearing loss. A “two-hit ” hypothesis has traditionally been proposed, whereby thinly developed bone overlying the superior canal is disrupted by a sudden change in intracranial pressure. Although the symptoms of SCD may be precipitated by head injury, no previous reports have described a temporal bone fracture directly causing SCD. Observations. Two patients sustained temporal bone fractures after closed head trauma, and developed unilateral otologic symptoms consistent with SCD. In each instance, computed tomography imaging revealed fractures extending through the bony roof of the superior semicircular canal. Conclusions and Relevance. Temporal bone fractures, which are largely treated nonoperatively, have not previously been reported to cause SCD. As it is a potentially treatable entity, SCD resulting from temporal bone fracture must be recognized as a possibility and diagnosed promptly if present. 1
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clinical outcomes of middle fossa craniotomy for superior semicircular canal dehiscence repair
Journal of Neurosurgery, 2016Co-Authors: Lawrance K Chung, Quinton Gopen, Marko Spasic, Nolan Ung, Kimberly Thill, Daniel T Nagasawa, Panayiotis Pelargos, Brittany L Voth, Daniel Hirt, Isaac YangAbstract:OBJECTIVE Superior semicircular canal dehiscence (SSCD) is a rare disorder characterized by the formation of a third opening in the inner ear between the superior semicircular canal and the middle cranial fossa. Aberrant communication through this opening causes a syndrome of hearing loss, pulsatile tinnitus, disequilibrium, and Autophony. This study analyzed the clinical outcomes of a single-institution series of patients with SSCD undergoing surgical repair by the same otolaryngologist and neurosurgeon. METHODS All patients who underwent SSCD repair at the University of California, Los Angeles, between March 2011 and November 2014 were included. All patients had their SSCD repaired via middle fossa craniotomy by the same otolaryngologist and neurosurgeon. Outcomes were analyzed with Fisher's exact test. RESULTS A total of 18 patients with a mean age of 56.2 years (range 27-84 years) and an average follow-up of 5.0 months (range 0.2-21.8 months) underwent 21 cases of SSCD repair. Following treatment, all patients (100%) reported resolution in ≥ 1 symptom associated with SSCD. Autophony (p = 0.0005), tinnitus (p = 0.0059), and sound- and/or pressure-induced dizziness (p = 0.0437) showed significant symptomatic resolution. Following treatment, 29% (2/7) of patients developed imbalance, 20% (1/5) of patients developed sound- and/or pressure-induced dizziness, and 18% (2/11) of patients developed aural fullness. Among patients with improved symptoms following surgical repair, none reported recurrence of symptoms at subsequent follow-up visits. CONCLUSIONS SSCD remains an underdiagnosed and undertreated condition. Surgical repair of SSCD using a middle fossa craniotomy is associated with a high rate of symptom resolution. Continued investigation using a larger patient cohort and longer-term follow-up could further demonstrate the effectiveness of using middle fossa craniotomy for SSCD repair.
Quinton Gopen - One of the best experts on this subject based on the ideXlab platform.
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failure to close the gap concomitant superior canal dehiscence in otosclerosis patients
Laryngoscope, 2020Co-Authors: Anne K Maxwell, Quinton Gopen, William H Slattery, Mia E MillerAbstract:OBJECTIVE Superior semicircular canal dehiscence (SSCD) causing conductive hearing loss with present reflexes is a known reason for stapes surgery failure. However, concomitant SSCD and otosclerosis occur rarely. We present a case series of SSCD diagnosed in positively identified otosclerosis patients. METHODS Retrospective review of clinical case series in two tertiary-referral neurotologic practices was performed. Clinical histories, operative findings, audiograms, and computed tomography (CT) images were reviewed for patients diagnosed with both SSCD and otosclerosis. Patients with present stapedial reflexes were excluded. Comprehensive literature review was performed. RESULTS Four cases were identified. Three reported improved hearing with partial or complete closure of the air-bone gap (ABG), including one patient with far-advanced otosclerosis. One patient had no improvement in pure tone average or ABG. One patient reported worsening of preoperative Autophony and pulsatile tinnitus, but none developed new postoperative third-window symptoms. CTs demonstrated both SSCD and otosclerosis. CONCLUSION Failure to close the ABG in patients with positively identified otosclerosis intraoperatively may be due to SSCD as an occult concomitant diagnosis. SSCD should be considered as a possible cause of persistent conductive hearing loss after stapes surgery. LEVEL OF EVIDENCE 4 Laryngoscope, 130:1023-1027, 2020.
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incidence of intraoperative hearing loss during middle cranial fossa approach for repair of superior semicircular canal dehiscence
Journal of Clinical Neuroscience, 2018Co-Authors: Michael Johanis, Isaac Yang, Quinton GopenAbstract:Abstract Introduction Superior semicircular canal dehiscence is a rare inner ear disorder characterized by an abnormal third opening between the superior semicircular canal and middle fossa. Symptoms include amplification of internal sounds, aural fullness, tinnitus, hearing loss, Autophony, sound-induced vertigo (Tullio phenomenon), pressure-induced vertigo (Hennebert sign), disequilibrium, nystagmus, oscillopsia, and headache. While no cure exists for SSCD, surgical treatment has proven to effectively minimize these symptoms. This study reviewed brainstem auditory evoked potentials (BAEPs) that were monitored intraoperatively to better understand hearing loss risks associated with surgical treatment for SSCD. Methods A retrospective chart review was conducted at the University of California, Los Angeles on adult patients with a confirmed diagnosis of SSCD who had undergone a middle cranial fossa repair from March 2011 to October 2017. A total of 142 cases of SSCD in 118 patients were repaired. Results The majority of patients’ BAEPs remained stable and had no intraoperative hearing changes (n = 135; 95.1%). Seven patients experienced intraoperative changes as determined by a prolongation and reduction of Wave V latency (4.9%). Of these seven cases, five experienced a return to baseline prior to the end of surgery, and had no post-operative changes in hearing (71.4%). Overall, only two of the 142 surgeries (1.4%) resulted in failure to normalize and, as such, these patients experienced permanent changes in hearing. Conclusion The results of this retrospective review demonstrate a low risk for hearing loss due to SSCD surgery via the middle fossa craniotomy approach.
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outcomes of middle fossa craniotomy for the repair of superior semicircular canal dehiscence
Journal of Clinical Neuroscience, 2017Co-Authors: Nolan Ung, Quinton Gopen, Lawrance K Chung, Carlito Lagman, Nikhilesh S Bhatt, Natalie E Barnette, Vera Ong, Isaac YangAbstract:Abstract Superior semicircular canal dehiscence (SSCD) is a rare defect of the arcuate eminence that causes an abnormal connection between the superior semicircular canal and middle cranial fossa. Patients often present with a variety of auditory and vestibular symptoms. Trigger avoidance is the initial strategy, but surgery may be necessary in debilitating cases. We retrospectively reviewed SSCD patients undergoing repair via a middle fossa craniotomy between March 2011 and September 2015. Forty-nine patients undergoing 58 surgeries were identified. Autophony was the most common symptom at presentation (n = 44; 90%). Mean follow-up was 10.9 months, with 100% of patients reporting resolution of at least one symptom. Aural fullness was the most commonly resolved symptom following surgical repair (n = 19/22; 86%). Hearing loss (n = 11/25; 44%) and tinnitus (n = 11/38; 29%) were the most common symptoms to persist following surgery. The most common symptom to develop after surgery was disequilibrium (n = 4/18; 22%). Upon comparing the overall pre-operative and post-operative groups, the number of patients with Autophony (p
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minimally invasive middle fossa keyhole craniectomy for repair of superior semicircular canal dehiscence
Operative Neurosurgery, 2017Co-Authors: Vanessa Trieu, Quinton Gopen, Marko Spasic, Lawrance K Chung, Nolan Ung, Panayiotis Pelargos, Brittany L Voth, Isaac YangAbstract:Background Superior semicircular canal dehiscence (SSCD) presents with varying degrees of auditory and vestibular dysfunction. The condition is confirmed on high-resolution computed tomography (CT) imaging, and symptoms are often improved by surgical repair. Although a classic middle fossa craniotomy has been used with good results, recent advances in technique have allowed for modification of the traditional approach into a smaller skin incision and a minimally invasive middle fossa keyhole craniectomy roughly 1.7 cm in diameter. Objective To delineate this novel approach and describe the technique for accurate localization of the dehiscence using preoperative measurements and intraoperative image guidance, thereby minimizing the need for a larger skin incision and craniotomy. Methods Patients were independently diagnosed with SSCD by the senior authors. Once relevant imaging was acquired, the novel keyhole technique was performed. Patients' vestibular and auditory symptoms before and after the procedure were assessed. Outcomes from a series of patients treated with this keyhole approach were tabulated and reported. Results Twelve cases from 11 patients were included in this series. Auditory symptoms had high rates of resolution with pulsatile tinnitus, internal amplification of sounds, and Autophony being resolved in a majority of cases. Only 2 cases reported hearing decline. Sound/pressure induced vertigo and disequilibrium also demonstrated high rates of resolution. No complications were reported. Conclusion The minimally invasive middle fossa keyhole craniectomy is a novel approach for the repair of SSCD. This approach may contribute to resolved auditory and vestibular symptoms with low morbidity and quick recovery.
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Case Report Temporal Bone Fracture Causing Superior Semicircular Canal Dehiscence
2016Co-Authors: Kevin A Peng, Isaac Yang, Sameer Ahmed, Quinton GopenAbstract:which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Importance. Superior semicircular canal dehiscence (SCD) is a third window lesion of the inner ear causing symptoms of vertigo, Autophony, tinnitus, and hearing loss. A “two-hit ” hypothesis has traditionally been proposed, whereby thinly developed bone overlying the superior canal is disrupted by a sudden change in intracranial pressure. Although the symptoms of SCD may be precipitated by head injury, no previous reports have described a temporal bone fracture directly causing SCD. Observations. Two patients sustained temporal bone fractures after closed head trauma, and developed unilateral otologic symptoms consistent with SCD. In each instance, computed tomography imaging revealed fractures extending through the bony roof of the superior semicircular canal. Conclusions and Relevance. Temporal bone fractures, which are largely treated nonoperatively, have not previously been reported to cause SCD. As it is a potentially treatable entity, SCD resulting from temporal bone fracture must be recognized as a possibility and diagnosed promptly if present. 1
John P. Carey - One of the best experts on this subject based on the ideXlab platform.
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surgical treatment of superior semicircular canal dehiscence syndrome
2019Co-Authors: Francis X Creighton, John P. CareyAbstract:Superior semicircular canal dehiscence syndrome (SCDS) is a clinical entity resulting in a myriad of audiological and vestibular symptoms. Pressure and/or sound-induced vertigo/nystagmus, Autophony, conductive hearing loss, and conductive hyperacusis are commonly seen in patients with SCDS. The physiologic mechanism of this syndrome is thought to be due to the dehiscence creating a low-impedance outlet for fluid waves in the labyrinth, commonly referred to as a third window. This shunts flow from the cochlea to the labyrinth, which both activates the vestibular system and decreases pressure driving the traveling fluid wave in the cochlea. Diagnosis of SCDS can be difficult and requires both radiographic evidence of a dehiscence and clinical evidence supporting SCDS as the etiology for a patient’s symptoms. Testing for SCDS includes high-resolution CT imaging, audiogram, cervical and ocular VEMP testing, head impulse testing, and visualization of sound- or pressure-induced eye movements in the plane of the affected superior canal. Traditional surgical repair of SCDS is via the middle fossa approach. This approach allows for the dehiscence to be seen directly and for it to be both plugged and resurfaced. This approach is preferred in the vast majority of patients, but in certain situations a transmastoid approach can offer benefits over the middle fossa approach. Surgical outcomes for repair of SCDS are quite favorable, with patients having improvement of Autophony, imbalance, and vertigo. Patients with predominately audiological symptoms have the highest likelihood of postoperative improvement. The majority of patients report an improvement in their quality of life postoperatively. Complications are rare but do occur in both the middle fossa and transmastoid approaches to SCDS repair. The most common complication is hearing loss, which is typically mild but can be profound in a low percentage of patients. The importance of proper patient selection and preoperative counseling on the risks of surgery cannot be overstated to ensure good surgical outcomes in SCDS repair.
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intraoperative neuromonitoring for superior semicircular canal dehiscence and hearing outcomes
Otology & Neurotology, 2014Co-Authors: Angela Wenzel, Lloyd B. Minor, Bryan K Ward, Eva K Ritzl, Sergio Gutierrezhernandez, Charles C Della Santina, John P. CareyAbstract:Superior semicircular canal dehiscence syndrome (SCDS) is a clinical syndrome described in 1998 in which a hole in the bone overlying the superior semicircular canal causes manifold symptoms, including Autophony, pulsatile tinnitus, bone-conduction hyperacusis, and sound- or pressure-evoked vertigo and nystagmus (1,2). One of the most studied surgical methods used for repair of the dehiscent canal is plugging via the middle cranial fossa approach. Individuals who have undergone this surgery report improvements in both Autophony and dizziness handicap inventory scores (3,4). However, a mild high-frequency sensorineural hearing loss persists in up to 25% of patients, with a few patients having more severe losses (5–7). Variations on this surgical technique include resurfacing the canal or approaching it via the mastoid cavity; however, postoperative outcomes from these approaches are less studied (8–10). Currently, it is unknown if there are any intraoperative predictors of postoperative hearing in patients undergoing this surgery. Historically, electrocochleography (ECochG) has been well studied as an electrophysiologic test for presumed endolymphatic hydrops (11–14). Patients with SCDS have also been shown to have an elevated summating potential to action potential (SP/AP) ratio, as measured by ECochG (15), and this finding appears to correct after surgical plugging of the dehiscent semicircular canal (16). ECochG and auditory brainstem reflexes (ABRs) have been monitored during some neurotologic procedures like cerebellopontine angle tumor surgery (17–19) as prognostic tools for postsurgical hearing outcomes (20–22). Their prognostic role in surgical repair of SCDS is unclear. The purpose of this study was to investigate whether intraoperative changes in ECochG and ABR are associated with postsurgical hearing outcomes in patients undergoing repair of SCD.
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near dehiscence clinical findings in patients with thin bone over the superior semicircular canal
Otology & Neurotology, 2013Co-Authors: Bryan K Ward, Lloyd B. Minor, Angela Wenzel, Eva K Ritzl, Sergio Gutierrezhernandez, Charles C Della Santina, John P. CareyAbstract:OBJECTIVE To determine whether patients with thin bone over the superior semicircular canal can develop signs or symptoms of superior canal dehiscence syndrome (SCDS). STUDY DESIGN Retrospective case series. SETTING Tertiary referral center. PATIENTS All patients from our institution found to have thin but not frankly dehiscent bone over the superior canal despite symptoms and signs of SCDS. MAIN OUTCOME MEASURES Preoperative CT imaging, symptoms, audiometry, vestibular evoked myogenic potentials (VEMP), and intraoperative electrocochleography (ECochG) results were reviewed. Symptoms were assessed at least 1 month postoperatively in all patients, and postoperative physiologic data are presented when available. RESULTS Ten patients (11 ears) had thin bone over the superior semicircular canal at surgery. All presented with Autophony or sound- and/or pressure-induced vertigo, in addition to at least 1 physiologic measure consistent with SCDS. CT imaging was read as showing either dehiscence (36%) or marked thinning of bone overlying the affected canal (64%). Preoperative median low-frequency air-bone gap (ABG) was elevated (10.9 dB; interquartile range [IQR], 8.8-12.5), with 4 patients demonstrating negative bone conduction thresholds. Patients had elevated oVEMP amplitude (median, 20.7; IQR, 6.7-22.1) μV and ECochG SP/AP ratios (median, 0.59; IQR, 0.54-0.67). Postoperative ABG and SP/AP ratio decreased significantly compared with preoperative values (p < 0.05), and all patients reported symptomatic improvement. CONCLUSION Symptoms typical of SCDS can occur in cases with thin but not dehiscent bone. Surgical plugging or resurfacing can reduce symptoms in such cases.
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second side surgery in superior canal dehiscence syndrome
Otology & Neurotology, 2012Co-Authors: Yuri Agrawal, Lloyd B. Minor, Michael C Schubert, Kristen L Janky, Marcela Davalosbichara, John P. CareyAbstract:Dehiscence of the superior semicircular canal is associated with a distinct set of vestibular and auditory phenomena, including sound- and pressure-evoked nystagmus, conductive hyperacusis, and Autophony (1–6). Characteristic deficits observed on physiologic testing include an air-bone gap on pure-tone audiometry and heightened responses on vestibular-evoked myogenic potential (VEMP) testing (2,7). Varying combinations of these symptoms and signs along with computed tomographic confirmation of superior canal (SC) dehiscence constitute SC dehiscence (SCD) syndrome. Dehiscence of the bone overlying the involved SC can be confirmed at the time of surgery, and repair of that dehiscence resolves the symptoms in most cases (8). Dehiscence of the SC is thought to cause the associated symptoms and signs by creating a “third mobile window,” allowing abnormal flow of endolymph in the canal after provocative stimuli (9–11). Temporal bone histopathologic studies as well as radiographic investigations demonstrate a 20% to 50% occurrence of bilateral dehiscences of the superior semi-circular canals, possibly owing to a congenital or developmental process (12, 13). We demonstrated in previous work that SC plugging surgery for SCD syndrome (SCDS) does not typically produce permanent global dysfunction of the operated labyrinth. Rather, it leads to an isolated deficit in the involved canal (14, 15). However, plugging both SCs would be expected to not only cause loss of the vestibuloocular reflex (VOR) for rapid downward head movements in the respective planes of the affected canals but throughout the entire range of approximately 90 degrees spanned by these canals. This would include higher frequency pitch downward head movements that occur during routine ambulation and running (16). Thus, bilateral SC plugging might be expected to cause vertical oscillopsia with associated visual impairment and gait instability and potentially more significant disability compared with the preoperative state (17). We report here a series of 5 patients with bilateral SCDS who elected to pursue sequential plugging of both SC dehiscences. We evaluated which symptoms prompted patients with bilateral SCDS to seek second-side surgery and the degree of disability associated with those symptoms. We also determined the frequency of disabling imbalance and oscillopsia after bilateral SC plugging in this small cohort.
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Improvement in Autophony symptoms after superior canal dehiscence repair.
Otology & neurotology : official publication of the American Otological Society American Neurotology Society [and] European Academy of Otology and Neu, 2010Co-Authors: Benjamin T. Crane, Lloyd B. Minor, Frank R. Lin, John P. CareyAbstract:Objective:Autophony, or the unusually loud or disturbing sound of a patient's own voice, can be a prominent and disabling symptom of superior canal dehiscence (SCD) syndrome. The current study measures Autophony symptoms before and after SCD plugging to quantify the benefits of surgery.Study Design:
Lloyd B. Minor - One of the best experts on this subject based on the ideXlab platform.
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superior semicircular canal dehiscence syndrome
Seminars in Neurology, 2020Co-Authors: Kristen K Steenerson, Benjamin T. Crane, Lloyd B. MinorAbstract:Superior canal dehiscence syndrome (SCDS) is a vestibular disorder caused by a pathologic third window into the labyrinth that can present with Autophony, sound- or pressure-induced vertigo, and chronic disequilibrium among other vestibulocochlear symptoms. Careful history taking and examination in conjunction with appropriate diagnostic testing can accurately diagnose the syndrome. Key examination techniques include fixation-suppressed ocular motor examination investigating for sound- or pressure-induced eye movements in the plane of the semicircular canal. Audiometry, vestibular evoked myogenic potentials, and computed tomography confirm the diagnosis. Corrective surgical techniques can be curative, but many patients find their symptoms are not severe enough to undergo surgery. Although a primarily peripheral vestibular disorder, as first-line consultants for most dizziness complaints, neurologists will serve their patients well by understanding SCDS and its role in the differential diagnosis of vestibular disorders.
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intraoperative neuromonitoring for superior semicircular canal dehiscence and hearing outcomes
Otology & Neurotology, 2014Co-Authors: Angela Wenzel, Lloyd B. Minor, Bryan K Ward, Eva K Ritzl, Sergio Gutierrezhernandez, Charles C Della Santina, John P. CareyAbstract:Superior semicircular canal dehiscence syndrome (SCDS) is a clinical syndrome described in 1998 in which a hole in the bone overlying the superior semicircular canal causes manifold symptoms, including Autophony, pulsatile tinnitus, bone-conduction hyperacusis, and sound- or pressure-evoked vertigo and nystagmus (1,2). One of the most studied surgical methods used for repair of the dehiscent canal is plugging via the middle cranial fossa approach. Individuals who have undergone this surgery report improvements in both Autophony and dizziness handicap inventory scores (3,4). However, a mild high-frequency sensorineural hearing loss persists in up to 25% of patients, with a few patients having more severe losses (5–7). Variations on this surgical technique include resurfacing the canal or approaching it via the mastoid cavity; however, postoperative outcomes from these approaches are less studied (8–10). Currently, it is unknown if there are any intraoperative predictors of postoperative hearing in patients undergoing this surgery. Historically, electrocochleography (ECochG) has been well studied as an electrophysiologic test for presumed endolymphatic hydrops (11–14). Patients with SCDS have also been shown to have an elevated summating potential to action potential (SP/AP) ratio, as measured by ECochG (15), and this finding appears to correct after surgical plugging of the dehiscent semicircular canal (16). ECochG and auditory brainstem reflexes (ABRs) have been monitored during some neurotologic procedures like cerebellopontine angle tumor surgery (17–19) as prognostic tools for postsurgical hearing outcomes (20–22). Their prognostic role in surgical repair of SCDS is unclear. The purpose of this study was to investigate whether intraoperative changes in ECochG and ABR are associated with postsurgical hearing outcomes in patients undergoing repair of SCD.
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near dehiscence clinical findings in patients with thin bone over the superior semicircular canal
Otology & Neurotology, 2013Co-Authors: Bryan K Ward, Lloyd B. Minor, Angela Wenzel, Eva K Ritzl, Sergio Gutierrezhernandez, Charles C Della Santina, John P. CareyAbstract:OBJECTIVE To determine whether patients with thin bone over the superior semicircular canal can develop signs or symptoms of superior canal dehiscence syndrome (SCDS). STUDY DESIGN Retrospective case series. SETTING Tertiary referral center. PATIENTS All patients from our institution found to have thin but not frankly dehiscent bone over the superior canal despite symptoms and signs of SCDS. MAIN OUTCOME MEASURES Preoperative CT imaging, symptoms, audiometry, vestibular evoked myogenic potentials (VEMP), and intraoperative electrocochleography (ECochG) results were reviewed. Symptoms were assessed at least 1 month postoperatively in all patients, and postoperative physiologic data are presented when available. RESULTS Ten patients (11 ears) had thin bone over the superior semicircular canal at surgery. All presented with Autophony or sound- and/or pressure-induced vertigo, in addition to at least 1 physiologic measure consistent with SCDS. CT imaging was read as showing either dehiscence (36%) or marked thinning of bone overlying the affected canal (64%). Preoperative median low-frequency air-bone gap (ABG) was elevated (10.9 dB; interquartile range [IQR], 8.8-12.5), with 4 patients demonstrating negative bone conduction thresholds. Patients had elevated oVEMP amplitude (median, 20.7; IQR, 6.7-22.1) μV and ECochG SP/AP ratios (median, 0.59; IQR, 0.54-0.67). Postoperative ABG and SP/AP ratio decreased significantly compared with preoperative values (p < 0.05), and all patients reported symptomatic improvement. CONCLUSION Symptoms typical of SCDS can occur in cases with thin but not dehiscent bone. Surgical plugging or resurfacing can reduce symptoms in such cases.
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second side surgery in superior canal dehiscence syndrome
Otology & Neurotology, 2012Co-Authors: Yuri Agrawal, Lloyd B. Minor, Michael C Schubert, Kristen L Janky, Marcela Davalosbichara, John P. CareyAbstract:Dehiscence of the superior semicircular canal is associated with a distinct set of vestibular and auditory phenomena, including sound- and pressure-evoked nystagmus, conductive hyperacusis, and Autophony (1–6). Characteristic deficits observed on physiologic testing include an air-bone gap on pure-tone audiometry and heightened responses on vestibular-evoked myogenic potential (VEMP) testing (2,7). Varying combinations of these symptoms and signs along with computed tomographic confirmation of superior canal (SC) dehiscence constitute SC dehiscence (SCD) syndrome. Dehiscence of the bone overlying the involved SC can be confirmed at the time of surgery, and repair of that dehiscence resolves the symptoms in most cases (8). Dehiscence of the SC is thought to cause the associated symptoms and signs by creating a “third mobile window,” allowing abnormal flow of endolymph in the canal after provocative stimuli (9–11). Temporal bone histopathologic studies as well as radiographic investigations demonstrate a 20% to 50% occurrence of bilateral dehiscences of the superior semi-circular canals, possibly owing to a congenital or developmental process (12, 13). We demonstrated in previous work that SC plugging surgery for SCD syndrome (SCDS) does not typically produce permanent global dysfunction of the operated labyrinth. Rather, it leads to an isolated deficit in the involved canal (14, 15). However, plugging both SCs would be expected to not only cause loss of the vestibuloocular reflex (VOR) for rapid downward head movements in the respective planes of the affected canals but throughout the entire range of approximately 90 degrees spanned by these canals. This would include higher frequency pitch downward head movements that occur during routine ambulation and running (16). Thus, bilateral SC plugging might be expected to cause vertical oscillopsia with associated visual impairment and gait instability and potentially more significant disability compared with the preoperative state (17). We report here a series of 5 patients with bilateral SCDS who elected to pursue sequential plugging of both SC dehiscences. We evaluated which symptoms prompted patients with bilateral SCDS to seek second-side surgery and the degree of disability associated with those symptoms. We also determined the frequency of disabling imbalance and oscillopsia after bilateral SC plugging in this small cohort.
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Improvement in Autophony symptoms after superior canal dehiscence repair.
Otology & neurotology : official publication of the American Otological Society American Neurotology Society [and] European Academy of Otology and Neu, 2010Co-Authors: Benjamin T. Crane, Lloyd B. Minor, Frank R. Lin, John P. CareyAbstract:Objective:Autophony, or the unusually loud or disturbing sound of a patient's own voice, can be a prominent and disabling symptom of superior canal dehiscence (SCD) syndrome. The current study measures Autophony symptoms before and after SCD plugging to quantify the benefits of surgery.Study Design:
Katherine D. Heidenreich - One of the best experts on this subject based on the ideXlab platform.
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VIDEO NEUROIMAGES Supplemental data at Neurology.org
2016Co-Authors: Gregory J. Basura, Scott J. Cronin, Katherine D. HeidenreichAbstract:Tullio phenomenon in superior semicircular canal dehiscence syndrome Tullio phenomenon refers to eye movements induced by sound.1 This unusual examination finding may be seen in superior semicircular canal dehiscence (SSCD) syndrome.2 This disorder is due to absent bone over the superior semicircular canal (figure). Patients complain of dizziness triggered by loud sound, aural fullness, Autophony, and pulsatile tinnitus. When Tullio phenomenon exists in SSCD syndrome, the patient develops a mixed vertical-torsional nystagmus in which the slow phase rotates up and away from the affected ear (video on the Neurology ® Web site at Neurology.org). This pattern of nystagmus aligns in the plane of the dehiscent semicircular canal and is due to excitation of its afferent nerves
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Tullio phenomenon in superior semicircular canal dehiscence syndrome
Neurology, 2014Co-Authors: Gregory J. Basura, Scott J. Cronin, Katherine D. HeidenreichAbstract:Tullio phenomenon refers to eye movements induced by sound.1 This unusual examination finding may be seen in superior semicircular canal dehiscence (SSCD) syndrome.2 This disorder is due to absent bone over the superior semicircular canal (figure ). Patients complain of dizziness triggered by loud sound, aural fullness, Autophony, and pulsatile tinnitus. When Tullio phenomenon exists in SSCD syndrome, the patient develops a mixed vertical-torsional nystagmus in which the slow phase rotates up and away from the affected ear (video on the Neurology ® Web site at Neurology.org). This pattern of nystagmus aligns in the plane of the dehiscent semicircular canal and is due to excitation of its afferent nerves.