Transmastoid semicircular canal occlusion: a safe and highly effective treatment for benign paroxysmal positional vertigo and superior canal dehiscence

Comparing Approaches for Repair of Superior Semicircular Canal Dehiscence

OBJECTIVE

Compare outcomes for subjects who underwent middle cranial fossa (MCF) or transmastoid (TM) repair of superior semicircular canal dehiscence (SSCD).

STUDY DESIGN

Retrospective cohort study.

SETTING

Quaternary-care, academic neurotology practice.

METHODS

Subjects who underwent MCF or TM repair of SSCD between December 1999 and April 2023 were identified. Main outcome measures included demographic data, length of surgery and hospital stay, clinical presentation, and audiometric testing.

RESULTS

Ninety-three subjects (97 ears) who underwent surgery for SSCD met inclusion criteria: 58.8% (57) via MCF, 39.2% (38) via TM, and 2.0% (2) via TM + MCF. Median operative time was shorter for the TM (35) compared to the MCF (29) approach (118 vs 151 minutes, P < .001). Additionally, median hospital stays were shorter for TM (36) compared to the MCF (56) approach (15.3 vs 67.7 hours, P < .001). Overall, 92% (49/53) of MCF and 92% (33/36) of TM surgeries resulted in an improvement or resolution of one or more symptoms (P = .84). There was no significant preoperative to postoperative change in the median air conduction pure-tone average (PTA), air-bone gap, or word recognition score in both the MCF and TM groups (P > .05). Improvements of >10 dB in the pre- to postoperative absolute change in bone conduction PTA were noted in 3 subjects in the MCF group and 4 subjects in the TM group (P = .49).

CONCLUSION

The TM approach for SSCD demonstrates shorter operative times and length of hospital stay. The TM and MCF approaches have comparable audiometric and clinical outcomes.

The History of Superior Semicircular Canal Dehiscence: A Bibliometric Analysis

OBJECTIVE

The treatment and understanding of superior semicircular canal dehiscence (SSCD) has seen significant developments over the past 25 years. Bibliographic analysis can provide insight into the evolution of research as well as highlight emerging areas. Reviewing a large volume of publications provides valuable insights into the citation patterns and collaborations of research groups. This study seeks to offer a comprehensive historical overview of SSCD and leading authors.

DATABASE REVIEWED

Web of Science Core Collection.

METHODS

A bibliometric analysis of the current literature on SSCD was conducted. A performance analysis and science mapping of the top 100 most cited articles was completed using a citation analysis. Two independent reviewers evaluated articles for relevance and adjugated by a third reviewer. Author and institution networks were examined.

RESULTS

Seven hundred ninety-one articles on the topic of SSCD were identified. The top 100 articles spanned over 23 years from 1998 to 2019 and were published in 30 different journals. The top 100 articles were cited 8253 times in literature. The document contents revealed 233 keywords and 238 author keywords. The articles were authored by a total of 291 authors, with only 4 single-authored documents.

CONCLUSIONS

SSCD has been highly researched in aspects of symptomatology, diagnosis, and treatment, as indicated by many highly cited articles that relate. However, the production of highly cited articles on SSCD displays a significant decrease after 2013, with only 17 of the top cited articles published since then.

Predictors of non-primary auditory and vestibular symptom persistence following surgical repair of superior canal dehiscence syndrome

Objective

Patients with superior canal dehiscence syndrome (SCDS) can present with a plethora of auditory and/or vestibular symptoms associated with a bony defect of the superior semicircular canal. While surgical repair is a reasonable option for patients with significant localizing symptoms, the degree of clinical improvement will vary among patients and poses challenges in outcome prediction. This study aims to assess the relationship between preoperative and postoperative symptoms and identify predictors of symptom persistence following repair.

Study design

Retrospective chart review.

Setting

Tertiary neurotology single-institution care center.

Main outcome measures

The primary outcome was to determine the proportion of resolved and persistent primary (most bothersome) and non-primary audiologic and vestibular symptoms following SCD repair. Secondary outcomes included comparison of patient, operative and radiologic characteristics between patients with resolved vs. persistent symptoms. Standardized patient questionnaires including 11 auditory and 8 vestibular symptoms were administered to patients at their preoperative and follow-up visits. Patient pre- vs. postoperative survey results, demographic and clinical characteristics, operative characteristics, audiometric data and cervical vestibular evoked myogenic potential (cVEMP) thresholds were compared via univariate χ2 and multivariate binary logistic regression analyses between those patients reporting full postoperative resolution of symptoms and persistence of one or more symptoms. Radiologic computed tomography (CT) measurements of superior canal dehiscence (SCD) defect size, location, and laterality were also compared between these two groups.

Results

Of 126 patients (132 ears) included in our study, 119 patients (90.2%) reported postoperative resolution (n = 82, 62.1%) or improvement (n = 37, 28.0%) of primary (most bothersome) symptoms, while 13 patients (9.8%) reported persistence of primary symptoms. The median (interquartile range) and range between surgery and questionnaire completion were 9 (4-28), 1-124 months, respectively. Analyzing all symptoms (primary and non-primary) 69 (52.3%) and 68 (51.1%) patients reported complete postoperative auditory and vestibular symptom resolution, respectively. The most likely persistent symptoms included imbalance (33/65/67, 50.8%), positional dizziness (7/20, 35.0%) and oscillopsia (44/15, 26.7%). Factors associated with persistent auditory symptoms included history of seizures (0% vs. 7.6%, p = 0.023), auditory chief complaint (50.0% vs. 70.5%), higher PTA (mean 19.6 vs. 25.1 dB, p = 0.043) and higher cervical vestibular evoked myogenic potential (cVEMP) thresholds at 1000 Hz (mean 66.5 vs. 71.4, p = 0.033). A migraine diagnosis (14.0% vs. 41.9% p < 0.010), bilateral radiologic SCD (17.5% vs. 38.1%, p = 0.034) and revision cases (0.0% vs. 14.0%, p = 0.002) were associated with persistent vestibular symptoms. Neither SCD defect size nor location were significantly associated with symptom persistence (P > 0.05).

Conclusions

Surgical repair for SCDS offers meaningful reduction in the majority of auditory and vestibular symptoms. However, the persistence of certain, mostly non-primary, symptoms and the identification of potential associated factors including migraines, PTA thresholds, cVEMP threshold, bilateral SCD, and revision cases emphasize the importance of individualized patient counseling and management strategies.

Trans-mastoid plugging of superior semicircular canal dehiscence: long-term follow-up

OBJECTIVE

To evaluate the long-term outcomes of trans-mastoid plugging of superior semicircular canal dehiscence (SSCD), focusing on complicated cases.

METHODS

In this cohort study, we included all patients who underwent trans-mastoid plugging of SSCD between 2009 and 2019. We evaluated the symptoms (autophony, sound-/pressure-induced vertigo, disequilibrium, aural fullness and pulsatile tinnitus) before and 1 year after surgery in the medical records. We systematically assessed the current symptoms 6.2 ± 3 years postoperative (range 2.2-12.3 years) using questionnaires sent by post and validated by telephone interviews. We also documented any complications and the need for further procedures. We compared pure tone and speech audiometry before and 1 year after surgery. Finally, the degree of mastoid pneumatisation and mastoid tegmen anatomy were reviewed on preoperative CT scans.

RESULTS

We included 24 ears in 23 patients. No complications were recorded, and none required a second procedure for SSCD. Following surgery, oscillopsia and Tullio phenomena resolved in all patients. Hyperacusis, autophony, and aural fullness were also settled in all patients except one. Balance impairment persisted to some degree in 35% of patients. No deterioration over the years was reported regarding the above symptoms. On average, bone conduction pure tone average pre- and 1 year postoperative were 13.7 ± 17 and 20.5 ± 18 dB, respectively (P = 0.002). Air bone gaps were reduced from 12.7 ± 8 to 5.9 ± 6 (P = 0.001). Two patients had a significant sclerotic mastoid, three had a prominent low-lying mastoid tegmen, and two had both. Anatomy had no effect on outcome.

CONCLUSION

Trans-mastoid plugging of SSCD is a reliable and effective technique which achieves long-lasting symptom control, even in cases with sclerotic mastoid or low-lying mastoid tegmen.

An anatomical study of the sigmoid sinus artery: Application to the transmastoid approach

INTRODUCTION

We aimed to investigate the morphological features of the artery that traverse the sigmoid sinus's lateral surface and to discuss this structure's clinical relevance.

METHODS

Ten sides from five cadaveric Caucasian heads were used for gross anatomical dissection to investigate the morphological features of the sigmoid sinus artery (SSA), and additional five sides were used for histological observation.

RESULTS

The SSA was found on eight out of ten sides (80%). The mean diameter of the SSA was 0.3 mm. The mean distance from the tip of the mastoid process to the artery was 20.3 mm. Histological observation identified extradural and intradural courses of SSA. The intradural course was further categorized into protruding and non-protruding types. In the protruding type, the SSA traveled within the dura but indented into the bone, making it more or less an intraosseous artery. In the non-protruding type, the SSA traveled within the dura but did not protrude into the bone but rather indented into the lumen of the SS. In all sections, both intradural and extradural courses were identified simultaneously.

CONCLUSIONS

When the mastoid foramen is observed, it does not always only carry an emissary vein but also an artery. The SSA could be considered a "warning landmark" during bone drilling for the transmastoid approach.

Meniere's disease: Pathogenesis, treatments, and emerging approaches for an idiopathic bioenvironmental disorder

Meniere's disease (MD) is a severe inner ear condition known by debilitating symptoms, including spontaneous vertigo, fluctuating and progressive hearing loss, tinnitus, and aural fullness or pressure within the affected ear. Prosper Meniere first described the origins of MD in the 1860s, but its underlying mechanisms remain largely elusive today. Nevertheless, researchers have identified a key histopathological feature called Endolymphatic Hydrops (ELH), which refers to the excessive buildup of endolymph fluid in the membranous labyrinth of the inner ear. The exact root of ELH is not fully understood. Still, it is believed to involve several biological and bioenvironmental etiological factors such as genetics, autoimmunity, infection, trauma, allergy, and new theories, such as saccular otoconia blocking the endolymphatic duct and sac. Regarding treatment, there are no reliable and definitive cures for MD. Most therapies focus on managing symptoms and improving the overall quality of patients' life. To make significant advancements in addressing MD, it is crucial to gain a fundamental understanding of the disease process, laying the groundwork for more effective therapeutic approaches. This paper provides a comprehensive review of the pathophysiology of MD with a focus on old and recent theories. Current treatment strategies and future translational approaches (with low-level evidence but promising results) related to MD are also discussed, including patents, drug delivery, and nanotechnology, that may provide future benefits to patients suffering from MD.

Impaired Vestibulo-Ocular Reflex on Video Head Impulse Test in Superior Canal Dehiscence: "Spontaneous Plugging" or Endolymphatic Flow Dissipation?

Surgical plugging of the superior semicircular canal (SSC) represents an effective procedure to treat disabling symptoms in superior canal dehiscence (SCD), despite resulting in an impaired vestibulo-ocular reflex (VOR) gain for the SSC. On the other hand, SSC hypofunction on video head impulse test (vHIT) represents a common finding in patients with SCD exhibiting sound/pressure-induced vertigo, a low-frequency air-bone gap (ABG), and enhanced vestibular-evoked myogenic potentials (VEMPs). "Spontaneous canal plugging" has been assumed as the underlying process. Nevertheless, missing/mitigated symptoms and/or near-normal instrumental findings would be expected. An endolymphatic flow dissipation has been recently proposed as an alternative pathomechanism for SSC VOR gain reduction in SCD. We aimed to shed light on this debate by comparing instrumental findings from 46 ears of 44 patients with SCD exhibiting SSC hypofunction with post-operative data from 10 ears of 10 patients with SCD who underwent surgical plugging. While no difference in SSC VOR gain values was found between the two groups (p = 0.199), operated ears developed a posterior canal hypofunction (p = 0.002). Moreover, both ABG values (p = 0.012) and cervical/ocular VEMP amplitudes (p < 0.001) were significantly higher and VEMP thresholds were significantly lower (p < 0.001) in ears with SCD compared to operated ears. According to our data, canal VOR gain reduction in SCD should be considered as an additional sign of a third window mechanism, likely due to an endolymphatic flow dissipation.

A report on quality-of-life outcomes following transmastoid plugging of superior semicircular canal dehiscence in a newly established service in a UK hospital

OBJECTIVE

This study aimed to evaluate the quality-of-life outcomes following transmastoid plugging of semicircular canal dehiscence in a newly established service in a UK hospital.

METHOD

Quality-of-life outcomes were measured using the Glasgow benefit Inventory score in three patients who underwent transmastoid plugging for superior semicircular canal dehiscence between September 2019 and March 2020. Patients also completed pre- and post-operative symptomatic questionnaires and vestibular-evoked myogenic potential testing.

RESULTS

All three patients reported an improvement in overall quality-of-life outcomes with a mean overall Glasgow Benefit Inventory score of +37 (range, +22.2-66.6). There were no immediate post-operative complications and hearing was preserved in all patients.

CONCLUSION

This study reported an initial successful experience with transmastoid plugging of superior semicircular canal dehiscence. In all patients, improvement in quality-of-life measures and symptoms was reported.

Occlusion of two semicircular canals does not disrupt normal hearing in adult mice

Vertigo is a debilitating disease affecting 15–20% of adults worldwide. Vestibular peripheral vertigo is the most common cause of vertigo, often due to Meniere's disease and benign paroxysmal positional vertigo. Although some vertigo symptoms can be controlled by conservative treatment and/or vestibular rehabilitation therapy, these treatments do not work for some patients. Semicircular canal occlusion surgery has proven to be very effective for these patients with intractable vertigo. However, its application is limited due to concern that the procedure will disrupt normal hearing. In this study, we investigated if occlusion of two semicircular canals would jeopardize auditory function by comparing auditory function and hair cell morphology between the surgical and contralateral ears before and after the surgery in a mouse model. By measuring the auditory brainstem response and distortion product otoacoustic emission 4 weeks post-surgery, we show that auditory function does not significantly change between the surgical and contralateral ears. In addition, confocal imaging has shown no hair cell loss in the cochlear and vestibular sensory epithelia, and scanning electron microscopy also indicates normal stereocilia morphology in the surgical ear. More importantly, the endocochlear potential measured from the surgical ear is not significantly different than that seen in the contralateral ear. Our study suggests that occlusion of two semicircular canals does not disrupt normal hearing in the mouse model, providing a basis to extend the procedure to patients, even those with normal hearing, benefitting more patients with intractable vertigo attacks.

Cochlear implantation and simultaneous posterior semicircular canal plugging

BACKGROUND

Intractable benign paroxysmal positional vertigo (BPPV) may be treated by plugging the affected semicircular canal (SCC). A cochlear implant (CI) can diminish subjective symptoms of tinnitus. We present a case with intractable BPPV and incapacitating tinnitus who underwent surgery, simultaneously plugging his posterior SCC (PSCC) and implanting an ipsilateral CI.

CASE

A 50-year-old male experienced single-sided deafness (SSD) with severe ipsilateral tinnitus, and intractable BPPV related to the ipsilateral PSCC. Two years earlier, he had been treated with a bone anchored hearing system (BAHS) for his single-sided hearing loss, but his tinnitus and BPPV persisted. The patient was elected for surgical plugging of the affected SCC and was offered a simultaneous ipsilateral CI to treat his hearing loss and reduce his disabling tinnitus. The procedure was initially clinically and subjectively successful, but the tinnitus worsened, following an MRI despite regular precautions.

CONCLUSION

This is the first case presentation of cochlear implantation performed concurrent to plugging of the ipsilateral PSCC. The outcome of the procedure was overall successful.

A Historical Perspective on Surgical Manipulation of the Membranous Labyrinth for Treatment of Meniere's Disease

Meniere's disease is an inner ear disorder without a known cause. Endolymphatic hydrops is a swelling of the endolymph spaces that has been observed consistently on post-mortem histology in patients with a history of Meniere's disease but can occur in asymptomatic individuals and in association with other diseases. Since its discovery, Meniere's disease has been a disorder managed primarily by otolaryngologists. Surgical treatments, therefore, have accompanied attempts at medical management. Inspired by patients' sensations of ear fullness and later by the histologic findings of hydrops, surgeons began manipulating the membranous labyrinth to relieve episodes of vertigo while attempting to preserve hearing. This review highlights this history of manipulation of the membranous labyrinth. These procedures indicate a rich history of innovation that parallels developments in otologic surgery. The studies involving patients are uniformly retrospective, with some procedures performed first in animal models of endolymphatic hydrops. Many approaches were endorsed by eminent otologic surgeons. Surgeries on the endolymphatic sac are performed by some surgeons today; however, procedures on the membranous labyrinth resulted in similar symptomatic relief through a minimally invasive technique, in many cases performed using only local anesthetic. Episodic vertigo in patients with Meniere's disease is a distressing symptom, yet spontaneous remissions are common. The reports of procedures on the membranous labyrinth reviewed here consistently indicated fewer vertigo episodes. Variable degrees of hearing loss were common following these procedures, and many were abandoned. Additional innovative surgeries are inevitable, but we must understand better the relationships among endolymphatic hydrops, Meniere's disease pathophysiology, and patient symptoms.

Transmastoid Occlusion Surgery for Superior Semicircular Canal Dehiscence Syndrome Improves Patient-Reported Quality-of-Life Measures and corrects cVEMP Thresholds and Amplitudes

OBJECTIVE

To determine the pre- and postoperative clinical, audiological, vestibular, and patient-reported measures in patients undergoing transmastoid occlusion surgery for superior canal dehiscence syndrome (SCDS).

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral centre, UK.

PATIENTS

All primary transmastoid occlusion surgeries for SCDS were included (tertiary centre, single-surgeon), January 2008 to July 2019.

INTERVENTIONS

Transmastoid superior canal occlusion surgery for SCDS.

MAIN OUTCOME MEASURES

We collated audiological (pure tone audiogram), vestibular (cervical vestibular evoked myogenic potentials [cVEMPs]), and patient-reported outcome measures (Dizziness Handicap Inventory and subjective symptom grading).

RESULTS

Fifty-two patients (55 ears) met the inclusion criteria. Thirty-one (56%) were female. Mean age was 47 years (range 29-63) and mean follow-up of 11.2 months. Six patients had bilateral disease, four of whom underwent sequential, bilateral surgery.Autophony was the most frequent presenting symptom, improving in 92%.Significant improvements were self-reported in patients' autophony (p < 0.0001), pressure- and noise-induced dizziness (p < 0.0001 and p < 0.0001), aural fullness (p = 0.0159), pulsatile tinnitus (p < 0.0001), perceived hearing loss (p = 0.0058), and imbalance (p = 0.0303).Overall Dizziness Handicap Inventory scores reduced from 45.9 to 27.4 (p < 0.0001), and across all subgroups of functional (p = 0.0003), emotional (p < 0.0001), and physical handicap (p = 0.0005).A 6.4-dB HL improvement in the air-bone gap (500-1000 Hz) occurred (95% confidence intervals 3.3-9.4 dB HL, p < 0.0001). There were no dead ears. cVEMP thresholds, when recordable, normalized in all except two ears.

CONCLUSIONS

Transmastoid occlusion is effective at improving patient-reported outcomes and normalizing cVEMP thresholds, though some symptoms, notably disequilibrium, persist to a variable degree.

Auditory Outcomes Following Transmastoid and Middle Cranial Fossa Approaches for Superior Semicircular Canal Dehiscence Repair

OBJECTIVE

To describe postoperative hearing outcomes following transmastoid (TM) and middle cranial fossa (MCF) approaches for semicircular canal dehiscence (SSCD) repair.

STUDY DESIGN

Retrospective review.

SETTING

Academic, tertiary referral center.

PATIENTS

Adults with SSCD who underwent repair between 2005 and 2019.

INTERVENTIONS

Pure tone audiometry pre- and postoperatively after SSCD repair.

MAIN OUTCOME MEASURES

Change in air-bone gap (ABG) at 250 and 500 Hz, pure tone average (PTA), bone conduction (BC), and air conduction (AC) thresholds at 500, 1000, 2000, and 4000 Hz for patients undergoing TM and MCF approaches for SSCD repair.

RESULTS

The average change in BC PTA for patients undergoing TM (n = 26) and MCF (n = 24) SSCD repair was not significantly different between the two groups. The first and final postoperative PTAs were recorded an average of 1.7 (range 0.30-3.0) and 29.1 (range 3.5-154) months postoperatively. For patients who underwent MCF repair, the average BC PTAs increased (+) by 2.2 dB HL (p 0.43) and 0.57 dB HL (p 0.88) at the first and final audiograms respectively compared to +1.27 dB HL (p 0.53) and a decrease (-) of 0.57 dB HL (p 0.63) for the TM group. The average changes in low frequency ABG for patients undergoing MCF repair were -4.7 dB (p 0.08) and -6.9 dB (p 0.15) at first and final audiograms respectively compared to -4.9 dB (p 0.06) and -4.1 dB (p 0.36) for patients who underwent TM repair. There was a high frequency hearing loss noted at 8000 Hz for the MCF (30.0 dB ± 18.7 preop; 41.7 dB ± 21.7 postop; p 0.01) and TM (32.1 dB ± 23.2 preop; 44.3 dB ± 29.6 postop; p 0.001) groups which persisted on long term follow up.

CONCLUSIONS

Both TM and MCF approaches to SSCD repair can be performed with long-term preservation of hearing. ABGs were reduced in each treatment group but did not reach significance. A high frequency hearing loss (8000 Hz) may be expected with either approach.

Relationship Between Clinical Features and the Arc and Length of Dehiscence in SCDS: A Single Center Review of 42 Cases

INTRODUCTION

Superior canal dehiscence syndrome (SCDS) is a rare disorder characterized by an array of audiovestibular symptoms due to a dehiscence of bone overlying the superior semicircular canal (SSC). In the presence of debilitating symptoms, surgical management, to plug or resurface the SCC is performed. Although computed tomography (CT) may overestimate the size or presence of a dehiscence due to a partial volume effect, it remains an invaluable diagnostic tool.

OBJECTIVES

To assess for correlation between the arc and length of dehiscence and clinical symptomology.

METHOD

A single-center, single-operator retrospective analysis of 42 patients who underwent trans mastoid plugging of SCC with confirmed radiological dehiscence of their SSC between January 2008 and July 2019 was undertaken. Patients were assessed based on seven predefined clinical symptoms. Length and arc of dehiscence's were evaluated by means of high resolution (0.5 mm) CT (HRCT), using multiplanar reconstruction (MPR). Receiver operating characteristics (ROC), and more specifically the area under the ROC curve (AUROC) were used to assess for statistical significance.

RESULTS

Our results demonstrate overall very little correlation between the arc and size of the dehiscence and symptoms. The only statistically significant correlation we found was between length of dehiscence and the presence of aural fullness.

CONCLUSION

SCDS is a debilitating condition with an array of symptoms on presentation. While dehiscence length demonstrated a correlation with aural fullness, no other symptomology in patients with radiologically evident SCDS demonstrated a statistically significant correlation either against the length or arc of dehiscence.

Refining surgical techniques for efficient posterior semicircular canal gene delivery in the adult mammalian inner ear with minimal hearing loss

Hearing loss is a common disability affecting the world's population today. While several studies have shown that inner ear gene therapy can be successfully applied to mouse models of hereditary hearing loss to improve hearing, most of these studies rely on inner ear gene delivery in the neonatal age, when mouse inner ear has not fully developed. However, the human inner ear is fully developed at birth. Therefore, in order for inner ear gene therapy to be successfully applied in patients with hearing loss, one must demonstrate that gene delivery can be safely and reliably performed in the mature mammalian inner ear. In this study, we examine the steps involved in posterior semicircular canal gene delivery in the adult mouse inner ear. We find that the duration of perilymphatic leakage and injection rate have a significant effect on the post-surgical hearing outcome. Our results show that although AAV2.7m8 has a lower hair cell transduction rate in adult mice compared to neonatal mice at equivalent viral load, AAV2.7m8 is capable of transducing the adult mouse inner and outer hair cells with high efficiency in a dose-dependent manner.

The resilience of the inner ear-vestibular and audiometric impact of transmastoid semicircular canal plugging

Background

Certain cases of superior semicircular canal dehiscence or benign paroxysmal positional vertigo can be treated by plugging of the affected semicircular canal. However, the extent of the impact on vestibular function and hearing during postoperative follow-up is not known.

Objective

To evaluate the evolution of vestibular function and hearing after plugging of a semicircular canal.

Methods

Six patients underwent testing before and 1 week, 2 months, and 6 months after plugging of the superior or posterior semicircular canal. Testing included caloric irrigation test, video Head Impulse Test (vHIT), cervical and ocular Vestibular Evoked Myogenic Potentials (VEMPs) and audiometry.

Results

Initially, ipsilateral caloric response decreased in all patients and vHIT vestibulo-ocular reflex (VOR) gain of each ipsilateral semicircular canal decreased in 4/6 patients. In 4/6 patients, postoperative caloric response recovered to > 60% of the preoperative value. In 5/6 patients, vHIT VOR gain was restored to > 85% of the preoperative value for both ipsilateral non-plugged semicircular canals. In the plugged semicircular canal, this gain decreased in 4/5 patients and recovered to > 50% of the preoperative value. Four patients preserved cervical and ocular VEMP responses. Bone conduction hearing deteriorated in 3/6 patients, but recovered within 6 months postoperatively, although one patient had a persistent loss of 15 dB at 8 kHz.

Conclusion

Plugging of a semicircular canal can affect both vestibular function and hearing. After initial deterioration, most patients show recovery during follow-up. However, a vestibular function loss or high-frequency hearing loss can persist. This stresses the importance of adequate counseling of patients considering plugging of a semicircular canal.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-021-10693-5.

The Impact of Superior Canal Dehiscence on Power Absorbance, Otoacoustic Emissions, and Hearing in Fat Sand Rats

BACKGROUND

Superior Semicircular Canal Dehiscence (SSCD) may lead to vestibular and auditory impairments.

OBJECTIVE

To study the effects of power absorbance (PA), Distortion Product Otoacoustic emissions (DPOAE), and hearing thresholds in normal ears of fat sand rats, after a bullotomy, creation and patching.

METHODS

SSCD was performed unilaterally in eight normal hearing animals while the contra-lateral un-operated ear was used as a control. Measures included auditory brain stem responses thresholds for air and bone conduction stimuli, DPOAEs and PA at peak pressure.

RESULTS

The normal PA pattern of the animals grossly resembled that of human ears. A bullotomy generated specific, large and significant (p < 0.0001) changes in PA without altering hearing thresholds. SSCD significantly decreased PA at low (p < 0.02) and increased at high frequencies (p < 0.03), but on a smaller scale than the bullotomy. SSCD, induced a mean air-bone gaps of 24.3 for clicks, and 31.2 dB for 1 kHz TB. SSCD also increased the DPOAEs levels by mean of 10.1 dB SPL (p < 0.03). Patching the dehiscence, reversed partially the PA changes, the auditory threshold shifts, and the DPOAEs levels to pre-SSCD values.

CONCLUSIONS

SSCD affects both incoming and emitting sounds from the ear, probably due to its effect on cochlear impedance and stiffness of the middle and inner ear. The presence of DPOAEs and ABGs indicated a "third window" disease, i.e., SSCD. Due to similar PA patterns after bullotomy and SCCD, PA alone has limited diagnostic yield for patients with SCCD.

Hearing Outcomes After Surgical Manipulation of the Membranous Labyrinth During Superior Semicircular Canal Dehiscence Plugging or Posterior Semicircular Canal Occlusion

OBJECTIVE

To analyze audiometric data after surgical manipulation of the membranous labyrinth during plugging of superior semicircular canal dehiscence (SSCD) or posterior semicircular canal occlusion (PSCO) for benign paroxysmal positional vertigo.

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary referral center.

PATIENTS

Patients undergoing plugging of SSCD or PSCO between 2009 and 2019.

MAIN OUTCOME MEASURES

Pre- and postoperative audiometric data were collected per AAO-HNS guidelines. Hearing outcomes at initial and last follow-up were compared. Subanalyses were performed for surgical approach and age.

RESULTS

Eighty-seven total procedures in 76 patients including 43 middle cranial fossa for SSCD, 29 transmastoid SSCD, and 15 PSCO. Mean preoperative air-conduction-pure-tone averages was 21.1±14.9 dB compared with 26.1 ± 19.6 dB at initial follow-up and 24.4 ± 18.6 dB at last follow-up (p = 0.006). Mean preoperative bone-conduction-pure-tone average was 14.3 ± 11.9 dB compared with 18.3 ± 15.6 dB at initial follow-up and 18.5 ± 16.9 dB at last follow-up (p < 0.001). There were five cases of hearing loss >20 dB including one case of profound sensorineural hearing loss >55 dB. PSCO resulted in the most hearing loss at initial follow-up but largely resolves with time. Transmastoid approaches for SSCD resulted in more hearing loss compared with middle cranial fossa. Hearing outcomes were generally stable for SSCD approaches but showed improvement over time for PSCO. Age >50 was associated with greater hearing loss of 5.2 ± 11.1 dB compared with 1.3 ± 10.5 dB but did not reach statistical significance (p = 0.110).

CONCLUSIONS

Surgical manipulation of the membranous labyrinth results in statistically significant hearing loss in a pooled analysis. Transient hearing loss is observed in PSCO and TM SSCD plugging was associated with postoperative hearing loss. There was a trend toward increased hearing loss in patients >50 years old.

Transmastoid Superior Semicircular Canal Plugging: A Prospective Analysis of Surgical Outcomes

OBJECTIVES

To assess the outcomes of the transmastoid superior semicircular canal plugging in patients with superior semicircular canal dehiscence (SSCD).

STUDY DESIGN

Prospective cohort study.

SETTING

Tertiary, university center.

PATIENTS

Patients with SSCD undergoing transmastoid superior semicircular canal plugging within a 30-month period.

INTERVENTIONS

Transmastoid superior semicircular canal occlusion.

MAIN OUTCOME MEASURES

We documented the surgical technique, pre- and postoperative (3-month review) dizziness handicap inventory scores, average hearing thresholds, low-frequency air-bone gap, six-canal video head-impulse-test responses, improvement of the auditory symptoms and complications.

RESULTS

Out of 30 patients with SSCD, 11 patients (12 ears) were enrolled with an average age 41.17 years (range 32-65 years). Oscillopsia resolved in all patients; DHI score improved from 56.7 (range 22-84) preoperatively to 25.83 (10-46) postoperatively (p = 0.001), while out of the nine patients with troublesome auditory symptoms, five patients noticed an improvement. The average pre- and postoperative hearing thresholds were 15.2 dB (range 3-32.5 dB) and 14.17 dB (range 5-30 dB) (p = 0.73), respectively. The average pre- and postoperative low-frequency air bone gap was 12.3 dB (range 5-20 dB) and 9.4 dB (range 0-20 dB), respectively (p = 0.24) (Table 1). There were no major complications; two patients developed postoperative benign paroxysmal positional vertigo.

CONCLUSION

Transmastoid plugging of the superior semicircular canal can safely and significantly improve the vestibular symptoms of the patients with SCDS, as well as the auditory symptoms in a substantial number of patients in a hearing-preservation way.

Current Trends, Controversies, and Future Directions in the Evaluation and Management of Superior Canal Dehiscence Syndrome

Patients with superior canal dehiscence syndrome (SCDS) can present with a range of auditory and/or vestibular signs and symptoms that are associated with a bony defect of the superior semicircular canal (SSC). Over the past two decades, advances in diagnostic techniques have raised the awareness of SCDS and treatment approaches have been refined to improve patient outcomes. However, a number of challenges remain. First, there is currently no standardized clinical testing algorithm for quantifying the effects of superior canal dehiscence (SCD). SCDS mimics a number of common otologic disorders and established metrics such as supranormal bone conduction thresholds and vestibular evoked myogenic potential (VEMP) measurements; although useful in certain cases, have diagnostic limitations. Second, while high-resolution computed tomography (CT) is the gold standard for the detection of SCD, a bony defect does not always result in signs and symptoms. Third, even when SCD repair is indicated, there is a lack of consensus about nomenclature to describe the SCD, ideal surgical approach, specific repair techniques, and type of materials used. Finally, there is no established algorithm in evaluation of SCDS patients who fail primary repair and may be candidates for revision surgery. Herein, we will discuss both contemporary and emerging diagnostic approaches for patients with SCDS and highlight challenges and controversies in the management of this unique patient cohort.

Triple Canal Occlusion for the Treatment of Intractable Menière's Disease

OBJECTIVE

Menière's disease can be a debilitating condition but in most cases the symptoms are controlled by lifestyle changes and medical management. However, some patients remain symptomatic despite medical treatment and have the option of more invasive surgical treatments. Surgical intervention for Menière's includes a range of interventions from grommet insertion, intratympanic steroids/Gentamicin, endolymphatic sac decompression, labyrinthectomy, and vestibular neurectomy. A recently described technique involves the occlusion of all three semi-circular canals as an alternative in intractable Menière's disease.

STUDY DESIGN

This is a case series of three patients who underwent triple canal occlusion for the treatment of intractable Menière's disease.

SETTING

Patients were selected from those who were referred to Queen Elizabeth Hospital in Birmingham, a tertiary referral center.

PATIENTS

Patients who were severely symptomatic despite medical treatment who were considering ablative therapy were offered the option of triple canal occlusion as an alternative.

INTERVENTION

We report a series of Menière's patients treated by triple canal occlusion, describe the rationale behind this intervention, the surgical technique, and preliminary results.

MAIN OUTCOME MEASURE

Each patient was followed up for a minimum of 2 years following the procedure. The main outcomes measures were the class of vertigo control and hearing threshold levels according to the American Academy of Otolaryngology-Head and Neck Surgery guidelines.

RESULTS

Of the three patients, two were men and one was woman, the age range was 45 years to 61 years old. Two patients with unilateral disease achieved class A control whereas one patient with bilateral disease achieved class B control. Two patients who underwent the procedure had little or no effect to their hearing on the treated side however one patient suffered a 30 dB hearing loss on the operative side.

CONCLUSIONS

Based on our limited experience and the early reports in the literature we consider that there are potential patient benefits for triple canal occlusion for intractable Menière's disease as an alternative to vestibular neurectomy due to the reduced morbidity and long-term efficacy.

Sealing of superior semicircular canal dehiscence is associated with improved balance outcomes postoperatively versus plugging of the canal in middle fossa craniotomy repairs: a case series

OBJECTIVE

The authors compared postoperative symptoms between patients with sealed and those with plugged semicircular canal dehiscence repairs.

METHODS

In total, 136 ears from 118 patients who underwent surgical repair for semicircular canal dehiscence were identified via chart review. Data from postoperative MRI scans showing preservation or loss of semicircular canal fluid signal and postoperative reports of autophony, amplification, aural fullness, tinnitus, hyperacusis, hearing loss, vertigo, dizziness, disequilibrium, oscillopsia, and headache were amalgamated and analyzed.

RESULTS

Patients with preservation of fluid signal were far less likely to have dizziness postoperatively (p = 0.007, OR 0.158, 95% CI 0.041-0.611). In addition, these patients were more likely to have tinnitus postoperatively (p = 0.028, OR 3.515, 95% CI 1.145-10.787).

CONCLUSIONS

The authors found that superior semicircular canal dehiscence patients who undergo sealing without plugging have improved balance outcomes but show more tinnitus postoperatively than patients who undergo plugging.

Benign Positional Paroxysmal Vertigo Treatment: a Practical Update

PURPOSE OF THE REVIEW

To define the best up-to-date practical approach to treat benign paroxysmal positional vertigo (BPPV).

RECENT FINDINGS

Both posterior and horizontal canal BPPV canalith repositioning maneuvers (Semont, Epley, and Gufoni's maneuvers) are level 1 evidence treatment for evidence-based medicine. The choice of maneuver (since their efficacy is comparable) is up to the clinician's preferences, failure of the previous maneuver, or movement restrictions of the patient. Maneuvers for controversial variants, such as anterior canal and apogeotropic posterior canal BPPV, have weaker evidence of efficacy. Despite this, these variants are increasingly diagnosed and treated. Maneuvers also play a role in the differential diagnosis with central vestibular disorders. Chair-assisted treatment may be of help if available while surgical canal plugging should be indicated in selected same-canal, same-side intractable severe BPPV. The primary evidence-based treatment strategy for BPPV should be physical therapy through maneuvers. Despite the high success rate of liberatory maneuvers, there is a low percentage of subjects who have unsatisfactory outcomes. These patients need to be investigated to identify recurrences, multiple canal involvement, associated comorbidities (migraine, persistent postural perceptual dizziness), or risk factors for recurrences (low vitamin D serum level). Future research should also identify the optimum maneuvers for variants whose diagnosis and treatment are still a matter of some debate.

Effectiveness of Canal Occlusion for Intractable Posterior Canal Benign Paroxysmal Positional Vertigo: A Systematic Review

Objectives

A last resort for therapy for intractable benign paroxysmal positional vertigo (BPPV) is mechanical occlusion of the posterior semicircular canal. The aim of this review was to assess the effect of posterior canal occlusion for intractable posterior canal BPPV on vertigo and to determine the risk of loss of auditory or vestibular function.

Data Sources

A systematic literature search according to the PRISMA statement was performed on PubMed, the Cochrane Library, Embase, Web of Science, and CINAHL. The last search was conducted in June 2018.

Review Methods

Cohort studies with original data and case reports describing >5 cases were included if they analyzed the effect of posterior semicircular canal obliteration in adults with intractable posterior BPPV on vertigo. Two authors screened titles and abstracts for eligibility. The first author screened full texts and analyzed the data.

Results

Eight retrospective studies met the eligibility criteria. The quality of all individual studies was rated fair. Canal occlusion was performed on 196 patients. All studies reported complete resolution of BPPV in all patients (100%). Among postoperatively tested patients, total loss of auditory function and vestibular function was reported in 2 of 190 (1%) and 9 of 68 (13%), respectively.

Conclusion

Posterior semicircular canal plugging resulted in 100% resolution of BPPV in patients with intractable BPPV in all studies. However, the strength of evidence was weak. Potential serious complications, such as deafness and loss of vestibular function, should be taken into account.

The pattern of hearing outcome following surgery of the semicircular canals

OBJECTIVE

To analyze demographic, clinical, surgical, and audiometric factors that may affect hearing outcome following surgery for the semicircular canals (SCC).

METHOD

This is a retrospective case review of adults who underwent surgeries for superior SCC (SSCC), lateral SCC (LSCC), or posterior SCC (PSCC) and whose data were extracted and analyzed for factors affecting the hearing outcome in these procedures.

RESULTS

Thirteen patients underwent surgery for SSCC, seven cases for the LSCC, one for the PSCC, and one case of combined PSCC/SSCC surgery. The mean age was 49.8 ± 12 years (21-66). There was no difference between the preoperative and postoperative pure tone average (PTA) thresholds at 0.5-3 kHz. Higher thresholds were noted at 4, 6, and 8 kHz postoperatively. Deterioration (>10 dB) in the bone-conduction (BC) PTA was demonstrated in 3 of 22 (13.6%) cases with no significant difference in the demographic, clinical, surgical, and preoperative audiometric parameters relative to the cases without PTA BC change. A significantly larger difference in PTA BC (pre- vs. postoperative) was seen for males. Small effect size was noted for Air conduction (AC) PTA in males, and moderate effect size for Word Recognition Score (WRS) in surgery for the LSCC compare to SSCC.

CONCLUSIONS

SCC surgeries carry a relatively low risk of deterioration in PTA BC. High frequency thresholds should also be included in postoperative hearing outcome assessment. Cases of LSCC for intractable Meniere's disease and surgery in males carry higher risk of poor postoperative hearing outcomes. Level of Evidence: 4.

The Vestibular System and Ageing

The world's population is ageing due to increased hygiene and improved medical care. Dizziness and imbalance frequently affect the elderly and is most common among individuals over the age of 60. In this age group approximately 30% of the population experience these debilitating symptoms at some point. They contribute to falls and frailty, which often result in hospitalization causing tremendous cost for the health care systems, and increased mortality. To make the matters worse balance disorders are often complex. Physicians face the difficulty of diagnosing the patient with the exact disorder especially since each disorder may manifest differently in each patient. In addition, several treatment options exist, however, with a low level of evidence. This chapter summarizes the underlying degenerative processes of the peripheral as well as the central vestibular system, diagnostic tools, the most common balance disorders in the elderly, and possible treatment options of these disorders.

Causes of Persistent Positional Vertigo Following Posterior Semicircular Canal Occlusion for Benign Paroxysmal Positional Vertigo

OBJECTIVE

To report causes of persistent recalcitrant positional vertigo (PRPV) after posterior semicircular canal occlusion (PSCO) for benign paroxysmal positional vertigo (BPPV).

STUDY DESIGN

Retrospective chart review.

SETTING

Single high-volume otology practice.

PATIENTS

Patients diagnosed with BPPV from 2007 to 2017.

INTERVENTION

PSCO and follow-up care including diagnostic and particle repositioning maneuvers for recurrent BPPV.

MAIN OUTCOME MEASURES

PRPV, defined as recalcitrant positional vertigo for any reason following PSCO.

RESULTS

Twenty seven PSCO operations were performed in 26 patients. Twenty five patients (96.2%) had resolution of the Dix-Hallpike test in the operated ear. Eleven patients (42.3%) developed BPPV postoperatively, three (11.5%) in the operated ear and eight (30.8%) in the contralateral ear. Five of eight patients (62.5%) who developed contralateral BPPV had unilateral BPPV preoperatively. Eight patients (30.8%) developed BPPV at least twice after surgery or did not resolve, qualifying as PRPV, and all but one of these events occurred in the nonsurgical ear. No instances of cerebrospinal fluid leak, postoperative infection, facial palsy, clinically significant hearing loss, or death occurred.

CONCLUSIONS

PSCO is a safe and effective option for recalcitrant BPPV. However, 30.8% of patients, including patients with initially unilateral BPPV, had recalcitrant positional vertigo postoperatively, usually due to contralateral BPPV. Patients considering PSCO should be counseled regarding this risk to ensure realistic expectations.

Stenting the Superior Petrosal Sinus in a Patient With Symptomatic Superior Semicircular Canal Dehiscence

Patients presenting superior semicircular canal dehiscence (SSCD) can experience symptoms such as conductive hearing loss, pulsatile tinnitus, autophony, and pressure-induced vertigo. Decreased cervical vestibular-evoked myogenic potentials (cVEMPs) thresholds and high-resolution computed tomography (HRCT) of the petrous bone are essential for diagnosis of SSCD syndrome. We report the case of a 43-year-old man suffering from constant right pulsatile tinnitus, intermittent autophony, and unsteadiness induced by physical exercise. An SSCD by the superior petrosal sinus (SPS) was confirmed on the right side by axial HRCT of the temporal bone reformatted in the plane of Pöschl and ipsilateral abnormally low elicited cVEMPs. Treatment options were discussed with the patient since the pulsatile tinnitus progressively became debilitating. Two options were considered: surgery or a new endovascular treatment; the patient chose the latter option. After stenting the right SPS, the intensity of the pulsatile tinnitus dramatically decreased. As there was no complication the patient was discharged at Day 1. The other symptoms improved progressively. By the 60-day follow-up visit the patient only reported a slight tinnitus worsened by physical exercise. Angiographic follow-up at 5 months confirmed the patency of the SPS. Stenting the SPS in patients with SSCD by the SPS appears to be an alternative to the existing surgical treatments.

Superior Canal Dehiscence: A Comparative Postmortem Multislice Computed Tomography Study

OBJECTIVE

Superior canal dehiscence is defined by missing bony coverage of the superior canal against the middle cranial fossa. The gold standard in diagnosis is high-resolution computed tomography (CT). A false-positive CT scan, identifying a dehiscence when one is not present, could lead to unnecessary surgical therapy. This study aims to compare postmortem CT scans with autopsy findings with regard to superior canal dehiscence.

STUDY DESIGN

Postmortem study.

SETTING

Tertiary referral center.

SUBJECTS AND METHODS

Twenty-two nontraumatic death cases within a 3-month period (January to March 2017) were included with 44 temporal bones. Each body underwent postmortem head CT prior to medicolegal autopsy. The middle fossa floor was exposed, and if present, the superior semicircular canal dehiscence was identified and measured. In each case, 3 comparable photographs were taken during the autopsy (left temporal bone, right temporal bone, overview).

RESULTS

Autopsy findings revealed bony dehiscences in 11% of the temporal bones, whereas CT scan revealed bony dehiscences in 16%. The length of the dehiscences were longer when measured by CT imaging.

CONCLUSION

The diagnosis of superior canal dehiscence syndrome requires high-resolution CT with clinical symptoms and physiologic evidence of a third mobile window. Our study underlines a mismatch between multislice CT imaging in the coronal plane and the presence of a dehiscence on autopsy.

Middle cranial fossa approach for the repair of superior semicircular canal dehiscence is associated with greater symptom resolution compared to transmastoid approach

BACKGROUND

Superior semicircular canal dehiscence (SSCD) is a disorder of the skull base that is gaining increasing recognition among neurosurgeons. Traditionally, the middle cranial fossa (MCF) approach has been used for the surgical repair of SSCD. However, the transmastoid (TM) approach is an alternative strategy that has demonstrated promising results.

METHODS

We performed independent searches of a popular database to identify studies that described outcomes following the surgical repair of SSCD through MCF and TM approaches. The primary outcome was symptom resolution.

RESULTS

Our analysis included 24 studies that described 230 patients that underwent either an MCF (n = 148, 64%) approach or a TM (n = 82, 36%) approach for primary surgical repair of SSCD. A greater percentage of patients in the MCF group experienced resolution of auditory symptoms (72% vs 59%, p = 0.012), aural fullness (83% vs 55%, p = 0.049), hearing loss (57% vs 31%, p = 0.026), and disequilibrium (75% vs 44%, p = 0.001) when compared to the TM group. The MCF approach was also associated with higher odds of symptom resolution for auditory symptoms (odds ratio [OR] 1.79, 95% confidence interval [CI] 1.14-2.82), aural fullness (OR 4.02, 95% CI 1.04-15.53), hearing loss (OR 2.91, 95% CI 1.14-7.42), and disequilibrium (OR 3.94, 95% CI 1.78-8.73). The mean follow-up was 9 months.

CONCLUSIONS

The literature suggests that the MCF approach for the repair of SSCD is associated with greater symptom resolution when compared to the TM approach. This information could help facilitate patient discussions.

Canalostomy As a Surgical Approach to Local Drug Delivery into the Inner Ears of Adult and Neonatal Mice

Local delivery of therapeutic drugs into the inner ear is a promising therapy for inner ear diseases. Injection through semicircular canals (canalostomy) has been shown to be a useful approach to local drug delivery into the inner ear. The goal of this article is to describe, in detail, the surgical techniques involved in canalostomy in both adult and neonatal mice. As indicated by fast-green dye and adeno-associated virus serotype 8 with the green fluorescent protein gene, the canalostomy facilitated broad distribution of injected reagents in the cochlea and vestibular end-organs with minimal damage to hearing and vestibular function. The surgery was successfully implemented in both adult and neonatal mice; indeed, multiple surgeries could be performed if required. In conclusion, canalostomy is an effective and safe approach to drug delivery into the inner ears of adult and neonatal mice and may be used to treat human inner ear diseases in the future.

Cochleovestibular gene transfer in neonatal mice by canalostomy

Impairments of the inner ear result in sensorineural hearing loss and vestibular dysfunction in humans. A large proportion of these disorders are congenital, and involve both auditory and vestibular systems. Therefore, genetic interventions to correct deficits must be administered during early developmental stages. In this study, we evaluated inner ear gene transfer in neonatal mice by canalostomy using an adeno-associated virus serotype 8 (AAV8) vector. AAV8 with the green fluorescence protein (GFP) gene was inoculated into the inner ear of the neonatal mice through the posterior semicircular canal (canalostomy). At 30 days following surgery, animals were subjected to swim tests and auditory brainstem response measurements. Then, the animals were euthanized and temporal bones were harvested for whole-mount preparation. GFP expression and morphological changes in the inner ear were assessed by immunohistochemistry. After surgery, no signs of vestibular dysfunction were found, and there were no significant differences in the auditory brainstem response threshold between AAV8-inoculated ears and nonsurgery ears. In the surgery ears, extensive GFP expression and no morphological lesions were detected in the cochlear and vestibular end organs. Robust GFP expression was found in inner hair cells, marginal cells, vestibular hair cells, and vestibular supporting cells. In conclusion, AAV8 inoculation through canalostomy into the inner ears of neonatal mice led to extensive overexpression of exogenous genes in the inner ear without affecting hearing or vestibular function. It serves as a promising approach for gene therapy of congenital cochleovestibular diseases.

Effectiveness of Transmastoid Plugging for Semicircular Canal Dehiscence Syndrome

Objectives (1) Evaluate changes in subjective symptoms in patients following transmastoid canal plugging for superior semicircular canal dehiscence (SSCD) syndrome. (2) Quantify changes in hearing in patients who have undergone transmastoid canal plugging for SSCD syndrome. Study Design Case series with chart review. Setting Single tertiary care institution. Subjects and Methods We retrospectively reviewed patients with SSCD who underwent repair with canal plugging via a transmastoid approach between January 2012 and January 2017. Symptom severity was assessed prospectively (autophony, sound/pressure-induced vertigo, disequilibrium, aural fullness, and pulsatile tinnitus) and after surgery. Pure-tone and speech audiometry were measured before and after surgery. Two-sided Wilcoxon rank-sum tests were used to evaluate changes in subjective symptoms and audiometric outcomes. Results Seventeen patients (19 ears) met inclusion criteria. The superior canal was successfully plugged via the transmastoid approach in all cases. Patients reported a statistically significant improvement in autophony, vertigo, aural fullness, and pulsatile tinnitus ( P < .01), without significant improvement in disequilibrium rating ( P = .06). There were no changes noted in pure-tone average or word recognition score; however, there was a statistically significant improvement in air-bone gap at 250 Hz of 10.9 dB ( P = .04) with 12.9-dB improvement in air conduction thresholds ( P = .02) and no difference (0.9 dB, P = .9) in bone conduction thresholds. Conclusion In our study, patients with SSCD demonstrated excellent hearing outcomes and resolution of most otologic symptoms after surgical repair. Transmastoid canal plugging, which has been described to date only in smaller case series, is a safe and effective alternative to the traditional middle cranial fossa approach.

Recent surgical options for vestibular vertigo

Vertigo is not a well-defined disease but a symptom that can occur in heterogeneous entities diagnosed and treated mainly by otolaryngologists, neurologists, internal medicine, and primary care physicians. Most vertigo syndromes have a good prognosis and management is predominantly conservative, whereas the need for surgical therapy is rare, but for a subset of patients often the only remaining option. In this paper, we describe and discuss different surgical therapy options for hydropic inner ear diseases, Menière's disease, dehiscence syndromes, perilymph fistulas, and benign paroxysmal positional vertigo. At the end, we shortly introduce the most recent developments in regard to vestibular implants. Surgical therapy is still indicated for vestibular disease in selected patients nowadays when conservative options did not reduce symptoms and patients are still suffering. Success depends on the correct diagnosis and choosing among different procedures the ones going along with an adequate patient selection. With regard to the invasiveness and the possible risks due to surgery, in depth individual counseling is absolutely necessary. Ablative and destructive surgical procedures usually achieve a successful vertigo control, but are associated with a high risk for hearing loss. Therefore, residual hearing has to be included in the decision making process for surgical therapy.

Characteristics and Treatment Outcomes of Benign Paroxysmal Positional Vertigo in a Cohort of Veterans

BACKGROUND

The Mountain Home Veterans Affairs (VA) Medical Center has been diagnosing and treating veterans with benign paroxysmal positional vertigo (BPPV) for almost 2 decades. The clinic protocol includes a 2-week follow-up visit to determine the treatment outcome of the canalith repositioning treatment (CRT). To date, the characteristics of BPPV and treatment efficacy have not been reported in a cohort of veterans with BPPV.

PURPOSE

To determine the prevalence and characteristics of veterans diagnosed with BPPV in a Veterans Affairs Medical Center Audiology Clinic and to examine treatment outcomes.

RESEARCH DESIGN

Retrospective chart review.

STUDY SAMPLE

A total of 102 veterans who tested positive for BPPV in the Vestibular Clinic at the Mountain Home VA Medical Center from March 2010 to August 2011.

RESULTS

In 102 veterans who were diagnosed with BPPV, the posterior semicircular canal was most often involved (75%), motion-provoked vertigo was the most common symptom (84%), and the majority (43%) were diagnosed with BPPV in their sixth decade. The prevalence of BPPV in the Audiology Vestibular Clinic was 15.6%. Forty-one percent of veterans reported a symptom onset within 12 months of treatment for BPPV; however, 36% reported their symptoms began > 36 months prior to treatment. CRT was effective (negative Dix-Hallpike/roll test) in most veterans (86%) following 1 treatment appointment (M = 1.6), but more than half reported incomplete symptom resolution (residual dizziness) at the follow-up appointment. Eighteen percent of veterans experienced a recurrence (M = 1.8 years; SD = 1.7 years).

CONCLUSIONS

The characteristics and treatment outcomes of BPPV in our veteran cohort was similar to what has been reported in the general population. Future work should focus on improving the timeliness of evaluation and treatment of BPPV and examining the time course and management of residual dizziness.

Benign paroxysmal positional vertigo: Diagnostic criteria Consensus document of the Committee for the Classification of Vestibular Disorders of the Bárány Society

This article presents operational diagnostic criteria for benign paroxysmal positional vertigo (BPPV), formulated by the Committee for Classification of Vestibular Disorders of the Bárány Society. The classification reflects current knowledge of clinical aspects and pathomechanisms of BPPV and includes both established and emerging syndromes of BPPV. It is anticipated that growing understanding of the disease will lead to further development of this classification.

Revision Surgery for Superior Canal Dehiscence Syndrome

OBJECTIVE

To identify factors associated with surgical failure for superior canal dehiscence syndrome (SCDS) and define rates of complications and cure after revision SCDS repair.

STUDY DESIGN

Retrospective patient series.

SETTING

Tertiary care referral center.

PATIENTS

Adults who underwent revision surgery for SCDS.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Initial surgical approach, intraoperative findings at the time of revision, persistence of symptoms, and complications for revision surgery.

RESULTS

Two hundred twenty-two surgical SCDS patients were identified, including 21 subjects who underwent 23 revision surgeries. Fourteen (61%) underwent previous middle fossa and nine (39%) underwent previous transmastoid approaches. Intraoperative findings showed that in 17 (74%) the previous material used to plug or resurface the canal was present but not entirely covering the dehiscence. In one (4%) the material was not present. In one (4%) the material was in proper position, whereas in four (17%) the material was in proper position with very thin bone adjacent. After revision surgery, symptoms were completely resolved in eight (35%), partially resolved in seven (30%), and not resolved in seven (30%). Findings of thin bone adjacent to the previous plug was associated with failure of symptom resolution (p = 0.03). Hearing outcomes were compared to a previously studied cohort of primary surgery patients, and outcomes were similar. Three subjects (13%) had a significant decrease in their word recognition score after revision surgery (p=0.52), and seven (30%) had a significant increase in their pure-tone average (p=0.78).

CONCLUSION

Revision surgery for SCDS can be curative in carefully selected patients, but there may be a higher failure rate than primary surgery, with similar hearing outcomes.

Audiologic, cVEMP, and Radiologic Progression in Superior Canal Dehiscence Syndrome

OBJECTIVE

To assess the change in hearing, vestibular function, and size of superior canal dehiscence (SCD) in patients with SCD syndrome over time.

PATIENTS

Adult patients with SCD in one or both ears with documented sign and symptom progression, as shown by the medical record, audiometry, cervical vestibular-evoked myogenic potentials (cVEMP), and computed tomography (CT).

INTERVENTION

Audiometry, cVEMPs, and temporal bone CT were performed on patients with high clinical suspicion of disease progression.

MAIN OUTCOME MEASURE

Audiometry (magnitude of the air-bone gap [ABG]), cVEMP (magnitude of the thresholds), and CT scans (size of the superior canal dehiscence) were analyzed. Symptoms were assessed at each clinical visit and before repeat testing.

RESULTS

Retrospective review of 250 patients with SCDS showed three patients with disease progression over time with follow-up testing as outlined above. All patients presented initially with mild symptoms, ABGs, low cVEMP thresholds, and small bony defects of the arcuate eminence. Four, 6, and 8 years later, progression of SCD signs and symptoms was observed in these three patients, respectively. Audiometry showed larger ABGs and lower cVEMP thresholds compared with previous testing. CT showed an increase in bony defect size.

CONCLUSION

Progression of SCD symptoms can be associated with a wider air-bone gap, lower cVEMP thresholds, and a larger bony defect. Prospective studies using validated measures of hearing loss and dizziness in patients who have not yet undergone surgery for SCD will determine the association between specific symptoms and objective test outcomes and how these change over time.

A Comparison of Surgical Treatments for Superior Semicircular Canal Dehiscence: A Systematic Review

OBJECTIVE

We investigate the postoperative subjective and objective outcomes of different surgical treatments for superior semicircular canal dehiscence (SSCD): vestibular signs, auditory signs, vestibular evoked myogenic potential test, pure tone audiogram, speech audiogram, or video-nystagmography.

DATA SOURCES

An electronic search performed in the PubMed, Cochrane Library, and EMBASE databases on 15th of September 2015. A systematic search was conducted. Articles were included if written in English, Dutch, German, or French language.

STUDY SELECTION

Original studies reporting on the pre and postoperative subjective and/or objective outcomes of surgical treatments for superior semicircular canal dehiscence were included.

DATA EXTRACTION

The methodological quality of the studies was independently assessed by two reviewers using a constructed critical appraisal, to assess the directness of evidence and the risk of bias. The results of the pre and postoperative subjective and/or objective outcomes were extracted.

DATA SYNTHESIS

Comparative study was conducted.

CONCLUSION

Surgical treatment for SSCD is particularly effective for vestibular symptoms and there is no evidence for improvement of hearing loss after surgical treatment. Since plugging using transmastoid approach had a lower complication rate, lower revision rate, and a shorter hospital stay, this treatment is recommended in high disabled SSCD patients.

Outcomes of Transmastoid Surgery for Superior Semicircular Canal Dehiscence Syndrome

OBJECTIVE

To present the management strategy and outcomes for our series of superior semicircular canal dehiscence syndrome (SSCDS) patients.

STUDY DESIGN

Retrospective cross-sectional study.

SETTING

Tertiary referral center.

PATIENTS

Thirty-seven consecutive patients referred from June 2011 to January 2015. Diagnosis of SSCDS based on presence of classical symptoms, computerized tomography, and concordant reduction in cervical vestibular evoked myogenic potentials.

INTERVENTIONS

Transmastoid resurfacing or plugging.

MAIN OUTCOME MEASURES

Pre- and postoperative pure tone audiometry. Nine item questionnaire grading pre- and postoperative symptom severity. Results of a short semi-structured telephone survey.

RESULTS

Twenty surgical patients: 13 women and 7 men. Mean age 52 years 6 months. Eighteen patients underwent transmastoid resurfacing and two underwent transmastoid plugging. Three of those who initially had resurfacing but had ongoing SSCD symptoms, subsequently had transmastoid plugging with complete resolution of third window symptoms. From the questionnaire there was improvement in mean scores for 8 of 9 of the SSCD symptoms, with statistically significant improvement in 6 of 9.

CONCLUSIONS

Management strategies and surgical techniques continue to evolve for SSCDS. We currently offer transmastoid resurfacing having informed patients of a 25% possibility of incomplete symptom resolution, and explain that plugging can be performed as a "second stage," if necessary. However, as we accrue more experience and there is more evidence from the literature we are considering whether to offer transmastoid plugging as our primary surgical procedure. In our experience, patients with multiple vestibular pathologies or atypical vestibular symptoms are the ones for whom SSCD surgery has not been curative, although they do report improvement in their SSCD symptoms.

Heterogeneity in Reported Outcome Measures after Surgery in Superior Canal Dehiscence Syndrome-A Systematic Literature Review

BACKGROUND

Superior canal dehiscence syndrome (SCDS) can be treated surgically in patients with incapacitating symptoms. However, the ideal treatment has not been determined.

OBJECTIVES

This systematic literature review aims to assess available evidence on the comparative effectiveness and risks of different surgical treatments regarding: (1) symptom improvement; (2) objectively measurable auditory and vestibular function; (3) adverse effects, and (4) length of hospitalization.

SEARCH METHOD AND DATA SOURCES

A systematic database search according to PRISMA statement was conducted on Pubmed, Embase, and Cochrane library. In addition, reference lists were searched. No correspondence with the authors was established. The last search was conducted on June 9, 2017.

STUDY ELIGIBILITY CRITERIA

Retrospective and prospective cohort studies were held applicable under the condition that they investigated the association between a surgical treatment method and the relief of vestibular and/or auditory symptoms. Only studies including quantitative assessment of the pre- to postoperative success rate of a surgical treatment method were included. Case reports, reviews, meta-analysis, and studies not published in English, Dutch, or German were excluded.

DATA COLLECTION AND ANALYSIS

The first author searched literature and extracted data; the first and last analyzed the data.

MAIN RESULTS

Seventeen studies (354 participants, 367 dehiscences) met the eligibility criteria and were grouped according to surgical approach. Seven combinations of surgical approaches and methods for addressing the dehiscence were identified: plugging, resurfacing, or a combination of both through the middle fossa (middle fossa approach); plugging, resurfacing, or a combination of both through the mastoid (transmastoid approach); round window reinforcement through the ear canal (transcanal approach). Several studies showed high internal validity, but quality was often downgraded due to study design (1). Outcome measures and timing of postsurgical assessment varied among studies, making it unfeasible to pool data to perform a meta-analysis.

CONCLUSION

A standardized protocol including outcome measures and timeframes is needed to compare the effectiveness and safety SCDS treatments. It should include symptom severity assessments and changes in vestibular and auditory function before and after treatment.

Outcomes of middle fossa craniotomy for the repair of superior semicircular canal dehiscence

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 10.9months, 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<0.0001), aural fullness (p=0.0006), hearing loss (p=0.0119), disequilibrium (p=0.0002), sound- and pressure-induced vertigo (p<0.0001), and tinnitus (p<0.0001) were significantly different. Improved clinical outcomes were demonstrated in patients undergoing SSCD repair through a middle cranial fossa approach. The most common presenting symptom (autophony) was also most likely to resolve after surgery. Hearing loss is less amenable to surgical correction. Disequilibrium developed in a small number of patients after repair.