Outcomes and complications in superior semicircular canal dehiscence surgery: A systematic review

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.

Unveiling the importance of the endoscope in the sealing of the superior canal dehiscence syndrome, how we do it

The superior canal dehiscence syndrome is a pathology that affects the arcuate eminence creating a "third window" between the inner ear and the middle fossa. This condition can lead to symptoms such as hearing loss, autophony, or sound-induced vertigo. Traditionally, surgical treatment has been performed by microscope-assisted temporal craniotomy, but when the dehiscence is in the medial part of the arcuate eminence the bone defect may not be seen. We present case series treated at our institution diagnosed of superior canal dehiscence syndrome involving the medial slope of the arcuate eminence. During surgery, the bone defect could not be visible with traditional microscopic techniques. Nonetheless, by introducing the endoscope with the 0º and 30º optics, the dehiscence could be clearly observed and treated correctly. Our results show a clinical improvement without side effects or complications in the patients undergoing this technique. Endoscope-assisted surgery is a safe procedure and provides a better visualization of medial defects.

Superior canal dehiscence syndrome: A review

Superior canal dehiscence syndrome (SCDS) is a vestibular disorder in which the presence of a pathological third window in the labyrinth causes several vestibular and cochlear symptoms. Herein, we review the diagnostic criteria and treatment of SCDS. The cause of SCDS is considered to be congenital or acquired; however, its etiology is not well known. Symptoms: Vertigo and/or oscillopsia induced by loud sounds (Tullio phenomenon) or stimuli that change the middle ear or intracranial pressure (fistula symptoms) with vestibular symptoms and hyperacusis and aural fullness with cochlear symptoms are characteristic clinical complaints of this syndrome. Neurological tests: Vertical-torsional eye movements can be observed when the Tullio phenomenon or fistula symptoms are induced. Conductive hearing loss with both a decrease in the bone conduction threshold at lower frequencies and an increase in the air conduction threshold at lower frequencies may be present on audiometry. Cervical and/or ocular vestibular evoked myogenic potentials are effective in strongly suspecting the presence of a pathologic third window in the labyrinth. Computed tomography (CT) imaging: High-resolution CT findings with multiplanar reconstruction in the plane of the superior semicircular canal consistent with dehiscence indicate SCDS. The Pöschl view along the plane of the superior semicircular canal and the Stenvers view perpendicular to it are recommended as CT imaging conditions. Findings from all three major diagnostic categories (symptoms, neurological tests, and/or CT imaging) are needed to diagnose SCDS. The surgical approaches for SCDS are as follows: the 1) middle cranial fossa approach, 2) transmastoid approach, and 3) round window and oval window reinforcement. Each technique has advantages and disadvantages.

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.

Hearing Results after Transmastoid Superior Semicircular Canal Plugging for Superior Semicircular Canal Dehiscence: A Meta-Analysis

OBJECTIVE

The transmastoid plugging of a superior semicircular canal is considered a safe and effective technique for the management of superior semicircular canal dehiscence (SSCD). The aim of this meta-analysis is to assess the postoperative hearing outcomes after the transmastoid plugging of the superior semicircular canal. Search method and data sources: A systematic database search was performed on the following databases until 30 January 2023: MEDLINE, Embase, Cochrane Library, Web of Science, CINAHL, ICTRP, and clinicaltrials.gov. A systematic literature review and meta-analysis of the pooled data were conducted. We also included a consecutive case series with SCDS for those who underwent transmastoid plugging treatment at our clinic.

RESULTS

We identified 643 citations and examined 358 full abstracts and 88 full manuscripts. A total of 16 studies were eligible for the systematic review and 11 studies for the meta-analysis. Furthermore, 159 ears (152 patients) were included. The postoperative mean air conduction threshold remained unchanged (mean difference, 2.89 dB; 95% CI: -0.05, 5.84 dB, p = 0.58), while the mean bone conduction threshold was significantly worse (mean difference, -3.53 dB; 95% CI, -6.1, -0.95 dB, p = 0.9).

CONCLUSION

The transmastoid plugging technique for superior semicircular canal dehiscence syndrome, although minimally worsening the inner ear threshold, is a safe procedure in terms of hearing preservation and satisfactory symptom relief.

Auditory and Vestibular Symptom Improvement With Surgery for Superior Canal Dehiscence Syndrome

OBJECTIVE

(1) To measure the change in auditory and vestibular symptoms following superior canal dehiscence (SCD) surgery, and (2) to determine differences in clinical features and surgical outcomes between superior canal dehiscence syndrome (SCDS) patients with primarily auditory or vestibular complaints.

STUDY DESIGN

Retrospective cohort study.

SETTING

Single surgeon series at the tertiary academic medical center from 2002 to 2021.

METHODS

Retrospective review of SCDS patients who underwent surgical repair. (1) Patients were administered a standardized symptom questionnaire at preoperative and follow-up visits, and results were compared with paired statistical testing. (2) Patients were divided into 2 cohorts based on either auditory or vestibular chief complaint and differences in demographic, clinical, and outcome variables were examined.

RESULTS

Our study included 113 patients with 118 operated ears. Twenty-seven patients (24%) had radiographic bilateral dehiscence. 10/11 auditory symptoms (91%) and 5/8 vestibular symptoms (63%) solicited on the questionnaire improved significantly with surgery, except for nonpulsatile tinnitus, sense of imbalance, positional dizziness, and oscillopsia. Analyses stratified by chief complaint (auditory vs vestibular) revealed overall similar characteristics and surgical outcomes. Patients with chief vestibular complaints underwent surgery at an earlier age (45.5 vs 53.9 years, p < 0.05).

CONCLUSION

SCD surgery alleviates a wide range of auditory and vestibular symptoms. Overall, we did not find significant differences between patients with chief auditory versus vestibular complaints, and both groups benefited from surgery. Symptoms are not directly linked to third-window physiology and certain vestibular symptoms may be more likely to persist. Bilateral dehiscence may play an important role in persistent symptoms as well.

Correlation Between Air-Bone Gap and Vestibular Aqueduct Size in Enlarged Vestibular Aqueduct Syndrome: A Systematic Review

The purpose of this review was to evaluate the air-bone gap with vestibular aqueduct size in enlarged vestibular aqueduct syndrome. According to the PRISMA guidelines we conducted a systematic review of the literature. Published international articles in English from 2000 to 2022 were screened, checking for studies that evaluated the air-bone gap of patients affected by enlarged vestibular aqueduct syndrome and the size of vestibular aqueduct. Data related to the hearing assessment and imaging investigation of enrolled participants were extracted. The chosen primary outcome measure was the correlation between air-bone-gap and vestibular aqueduct size. The database search allowed us to screen 485 articles and to select 5 articles discussing this topic for a total of 349 patients. Two studies showed a positive correlation between air-bone gap and vestibular aqueduct size, one only a trend and two no correlation. To date, it is not possible to draw conclusions whether or not there is a positive correlation between air-bone gap and vestibular aqueduct size in enlarged vestibular aqueduct syndrome. Higher quality studies would be conducted with standardized outcome measures to clarify the specific research question.

Audiometric Outcomes After the Middle Cranial Fossa Repair of Superior Semicircular Canal Dehiscence

OBJECTIVE

To evaluate the audiometric outcomes after the middle cranial fossa approach (MCF) for superior canal dehiscence (SCD) repair.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary referral center.

PATIENTS

SCD cases presented to a single institution between 2012 and 2022.

INTERVENTIONS

The MCF repair of SCD.

MAIN OUTCOME MEASURES

Air conduction (AC) threshold (250-8,000 Hz), bone conduction threshold (BC) (250-4,000 Hz), and air bone gap (ABG) (250-4,000 Hz) at each frequency, pure tone average (PTA) (500, 1,000, 2,000, 3,000 Hz).

RESULTS

Among 202 repairs, 57% were bilateral SCD disease and 9% had previous surgery on the affected ear. The approach significantly narrowed ABG at 250, 500, and 1,000 Hz. The narrowing of ABG was achieved by both decreased AC and increased BC at 250 Hz, but mediated primarily by increased BC at 500 Hz and 1,000 Hz. Among cases without previous ear surgery, mean PTA remained in the normal hearing range (mean: preop, 21 dB; postop, 24 dB) and clinically important hearing loss (PTA increased by ≥10 dB) after the approach was noted in 15% of cases. Among cases with previous ear surgery, mean PTA remained in the mild hearing loss range (mean: preop, 33 dB; postop, 35 dB) and clinically important hearing loss after the approach was noted in 5% of cases.

CONCLUSION

This is the largest study to date examining the audiometric outcomes after the middle cranial fossa approach for SCD repair. Findings of this investigation support that the approach is effective and safe with long-term hearing preservation for most.

Positioning for Middle Cranial Fossa Repair of Superior Semicircular Canal Dehiscence

Superior semicircular canal dehiscence (SCD) repair through the middle cranial fossa approach is typically performed on a patient in the supine position and the patient’s head is turned to the contralateral side and secured with surgical pinions or supported on a headrest. However, traditional supine positioning method may place strain on the patient’s neck, limit the surgeon’s visualization of the dehiscence due to inadequate head rotation, and compromise the ergonomic positioning of the surgeon. Here, we present a novel positioning method for middle fossa SCD repair that allows for optimal head rotation in a semi-supine position, requires less set-up and patient manipulation than the park bench position, and does not require the use of surgical pins.

Manual neuronavigation for superior semicircular canal dehiscence surgery

Background

Intraoperative identification of a superior semicircular canal (SSC) dehiscence via the middle cranial fossa approach (MCFA) remains a difficult endeavor without a neuronavigation system. To address these challenges, we propose a technique to localize the SSC dehiscence intraoperatively using certain anatomical landmarks.

Method

Three anatomical landmarks should be identified on preoperative radiological images: the distance from the squamous part of the temporal bone to the dehiscent SSC, the lower limit of the craniotomy, and the exact location of the craniotomy in relation to the bony external auditory canal. The use of these landmarks intraoperatively can allow the surgeon to correctly identify the position of the SSC. Two instructional videos explaining this technique are presented.

Conclusion

The proposed manual neuronavigation technique seems to be an accurate, safe, and cost-effective alternative technique for use in SSC dehiscence surgery.

Postoperative Pneumolabyrinth Following the Middle Cranial Fossa Approach for Superior Semicircular Canal Dehiscence Repair, 2014-2020

OBJECTIVE

The present study investigates risk factors and clinical outcomes of postoperative pneumolabyrinth following the middle cranial fossa approach for superior semicircular canal dehiscence repair, a complication that has not been documented previously.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary/quaternary care referral center.

METHODS

We conducted a retrospective review of 332 middle cranial fossa procedures from 2014 to 2020 at a tertiary/quaternary care institution. Upon identifying pneumolabyrinth cases from postoperative computed tomography temporal bone scans, we conducted multivariable logistic regression analysis to explore demographic and clinical factors that were independently linked to this complication. We also compared the rates of postoperative symptoms among patients with different grades of pneumolabyrinth.

RESULTS

We identified 41 (12.3%) pneumolabyrinth cases. Patients with older age, higher preoperative pure tone average, and frank dehiscence were at higher risk for pneumolabyrinth. Furthermore, patients with pneumolabyrinth reported significantly higher rates of postoperative dizziness and exhibited significantly greater pure tone average and air-bone gap postoperatively as compared with patients without pneumolabyrinth. Finally, higher-grade pneumolabyrinth was associated with increased rates of postoperative hearing loss, and grade III pneumolabyrinth was associated with higher rates of postoperative tinnitus vs grade I and II cases.

CONCLUSION

Pneumolabyrinth following the middle cranial fossa approach was associated with poor clinical outcomes, including dizziness and auditory impairment. Old age, high preoperative pure tone average, and frank dehiscence were risk factors for this complication. The highlighted parameters may be important to note when considering this approach as a treatment option and while monitoring postoperative recovery.

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.

Postoperative Outcomes of Patients with Thin Bone Overlying the Superior Semicircular Canal: A Single Institution's Experience

BACKGROUND

Superior semicircular canal dehiscence (SSCD) is defined by a bony defect overlying the superior semicircular canal (SSC) in the middle cranial fossa floor, causing a myriad of vestibular and auditory symptoms. Patients with thin bone without full dehiscence overlying the SSC also present with similar symptoms. There are currently no guidelines for surgical management of patients with thin bone. The authors offer their experience with thin bone patients to characterize their symptomatology and explore whether these patients benefit from surgical intervention typically offered to SSCD patients.

METHODS

Two hundred fifty-six patients evaluated for SSCD from 2011 to 2019 were reviewed. High-resolution coronal computed tomography scans with 0.6-mm slice thickness of the temporal bones were assessed to determine whether the patient had a true dehiscence or a thin bone covering overlying the SSC. Bone that was ≤0.5 mm was considered to be "thin bone." Parameters of interest included patient demographics as well as preoperative and postoperative symptomatology. A P value < 0.05 was considered statistically significant.

RESULTS

Forty-eight patients met inclusion criteria of having "thin bone." The mean age was 48.13 ± 12.03 years, and 65.5% of patients were female. Of the preoperative symptoms evaluated, the greatest postoperative symptomatic resolution was noted in hearing loss (92.3%), vertigo (94.4%), and oscillopsia (100%). Dizziness (56.5%) had the lowest symptomatic resolution rate.

CONCLUSIONS

Surgical management of thin bone patients via middle fossa craniotomy, a similar technique to SSCD repair, provides significant symptomatic resolution. Therefore, surgery should be considered in thin bone patients with debilitating symptoms, albeit not having a true dehiscence.

Superior semi-circular canal dehiscence syndrome: quantifying the effectiveness of treatment from the patient's perspective

Background

Superior semi-circular canal dehiscence syndrome is a disorder characterised by auditory and vestibular symptoms that can significantly impact quality of life, and yet it has no disease-specific quality of life instrument.

Method

Thirty-six patients who underwent transmastoid superior semicircular canal resurfacing and plugging were included from an initial cohort of 60 surgically managed patients. A sub-cohort of 19 consecutive patients completed validated symptom and quality of life questionnaires before and after surgery. Of the 36 patients, 31 participated in a telephone semi-structured interview post-operatively.

Results

Following surgery, there was a statistically significant improvement in autophony index score (p = 0.02), symptom severity score (p < 0.001) and sound hypersensitivity (p = 0.01). Thematic analysis of telephone interviews suggested three main symptom themes: auditory hypersensitivity, dysequilibrium, headache and concentration difficulties. Dysequilibrium was found to persist post-operatively.

Conclusion

Surgery improves overall symptoms and quality of life. However, important symptom themes may be overlooked using the outcome measures that are currently available. A unified disease-specific outcome measure is urgently required to better understand the impact of symptoms and measure treatment effects.

Long-Term Outcomes of Round Window Reinforcement for Superior Semicircular Canal Dehiscence Syndrome

OBJECTIVE

To report long-term patient reported outcome measures (PROMs) after standardized round window rein-forcement (RWR) with thin cartilage and perichondrium for superior semicircular canal dehiscence syndrome (SSCDS).

METHODS

Cross-sectional survey in 2020 and retrospective longitudinal study of outcomes at 3 months, 1 year, and last follow-up after 28 consecutive RWRs. Endpoints were the last follow-up for PROMs and 1 year postoperatively for audiometry and cVEMP.

RESULTS

At the last follow-up (mean 2.4 years postoperatively), improvement was reported for 19/28 ears (68%) in symptoms overall; for 17/27 ears (63%) in auditory symptoms, and for 12/24 (50%) in vestibular symptoms. Nine ears (32%) required further surgery. No major complications occurred. On the group level, postoperative improvement at 3 months declined significantly for auditory and vestibular symptoms over time, and stayed stable beyond 1 year. Improved ears had on average 2.9 years follow-up. Improvement correlated significantly with SSCD length, and was associated with contralateral dehiscence. Thirteen ears (46%) had another potential cause of vestibular symptoms. This group showed significantly less improvement. Audiometric test results did not predict PROMs.

CONCLUSIONS

Since long-term outcomes do not compare with those reported for plugging and repair, RWR is not suggested as a first line intervention for SSCDS. Considering the stable rates of improvement on average 2.9 years postoperatively and the absence of major complications, RWR may be an alternative to plugging or repair in fragile patients who do not accept the risk of complications with more invasive surgery, and who accept that results may deteriorate over time.

Hearing Outcomes of Transmastoid Plugging for Superior Canal Dehiscence Syndrome by Underwater Endoscopic Surgery: With Special Reference to Transient Bone Conduction Increase in Early Postoperative Period

OBJECTIVE

To investigate the influence on hearing of transmastoid plugging of the superior semicircular canal accompanied with membranous superior canal transection by underwater endoscopic ear surgery (UWEES) for the superior semicircular canal dehiscence syndrome.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center.

PATIENTS

Seven patients underwent plugging with membranous superior canal transection with UWEES from 2017 to 2019.

INTERVENTION

Bone conduction (BC) thresholds (250, 500, 1000, 2000, 4000 Hz) were repetitively examined in early postoperative period.

MAIN OUTCOME MEASURES

Subjective symptoms and pure-tone audiometry.

RESULTS

Transient BC threshold increase was detected in all cases in early postoperative period and hearing levels were ameliorated in 1 to 2 months. The mean maximum BC threshold elevations (dB) during the early postoperative period (within 1 mo) and the postoperative stable hearing period (after 2 mo) were 18.6 and 2.9 at 250 Hz, 24.3 and 8.6 at 500 Hz, 26.4 and 8.6 at 1000 Hz, 28.6 and 7.1 at 2000 Hz, and 30.0 and 0.8 (except for scale-out cases) at 4000 Hz. respectively. The mean maximum BC thresholds in the early period were significantly elevated compared with those in the stable period at each frequency (p < 0.01).

CONCLUSIONS

Hearing outcomes of transmastoid plugging with transection of the membranous superior canal by using UWEES were found favorable in a long-term follow-up. However, it caused transient reversible hearing loss in all cases. The BC increase in early postoperative period may not cause permanent hearing loss but improvement for the surgical technique may still be necessary.

Evaluation of the transmastoid plugging approach for superior semicircular canal dehiscences: a retrospective series of 30 ears

PURPOSE

The classical surgical approach for superior semicircular canal dehiscences (SSCD) is via the extradural middle cranial fossa. This pathway is used to resurface or to plug the SSC. In this paper, we present long-term data on an alternative route: the transmastoid pathway. The predictive factors for a successful surgery are equally presented in this paper.

METHODS

Thirty reports of patients operated between September 2007 to January 2020 were analysed. SSCD was confirmed by the association of concordant complaints, audiometric data, cervical vestibular evoked myogenic potentials (cVEMP) responses and computerized tomography findings. Before and after surgery, the following factors were analysed: auditory and vestibular subjective symptoms, Tullio phenomenon, pure-tone audiometry thresholds for air and bone conduction, air-bone gap, cVEMP threshold, and computerized tomography data, for instance the size of the dehiscence.

RESULTS

The follow-up is 21 months on average. The transmastoid approach significantly improves all symptoms (although there were less probing results for the vestibular symptoms). Objectively, we can observe, a closure of the audiometric air-bone gap on the low frequencies and an improvement in the cVEMP. The only correlation that was identified was between the preoperative cVEMP results and the postoperative air conduction.

CONCLUSIONS

The originality of this study is the long postoperative follow-up. It allowed us to evaluate the symptoms in the long term and to determine a predictive factor of postoperative complication, which has not yet been described until today.The transmastoid plugging technique is safe and effective. Additional long-term data with a larger cohort are needed to confirm our results and correlation studies.

Intraoperative Electrocochleography Correlates to Outcomes in Transmastoid and Middle Cranial Fossa Superior Semicircular Canal Dehiscence Repair

OBJECTIVE

To determine the degree to which electrocochleography (ECoG) correlates with auditory and vestibular outcomes after repair of superior semicircular canal dehiscence (SSCD) via transmastoid (TM) and middle cranial fossa (MCF) approaches.

STUDY DESIGN

Retrospective review.

SETTING

Academic tertiary referral center.

PATIENTS

Adults with SSCD who underwent repair between 2005 and 2019.

INTERVENTION

Pre-, intra-, and postoperative ECoG.

MAIN OUTCOME MEASURES

Patient-reported vestibular and auditory symptoms; pre-, intra-, and postoperative ECoG measures, dizziness handicap inventory (DHI) scores.

RESULTS

Forty-six patients underwent SSCD repair (40 unilateral, six bilateral) between 2005 and 2019, including 24 MCF and 28 TM approaches. There were no differences in preoperative, intraoperative, or postrepair ECoG SP/AP values between the MCF and TM groups (p 0.12, 0.77, 0.58). Patients had subjective improvement in vestibular symptoms (or stable vestibular function in patients operated for predominantly auditory manifestations) with both approaches (MCF: 87.5%; TM: 92.3%; p 0.64). A successful outcome correlated with intraoperative SP/AP ratio normalization (p 0.0005). Similarly, DHI scores were similar in both groups preoperatively (p 0.66) and returned to their preoperative baseline postoperatively with both (p 0.52). Reported vestibular symptoms persisted or worsened more often in patients with migraine (66.6% vs. 28.9%, p 0.03), and with persistently abnormal ECoG measures, though the latter was not statistically significant in this population (38% vs. 15%, p 0.10). Patients had subjective improvement or stability in auditory symptoms using either approach (MCF: 96%; TM: 100%; p 0.62), also correlating with SP/AP ratio normalization (p 0.008).

CONCLUSIONS

Correction of abnormal preoperative ECoG reliably correlates to patient symptom improvement after SSCD repair. No significant differences in postoperative outcomes were noted between patients undergoing TM versus MCF repair. Circumspection regarding the likelihood of an ideal outcome after SSCD repair should be exercised when counseling patients with concomitant migraine.

DEFINE PROFESSIONAL PRACTICE GAP AND EDUCATIONAL NEED

It is not certain whether outcomes differ between the two dominant approaches for SSCD repair. Surgeons and patients would benefit from an intraoperative metric that reflects satisfactory plugging of SSCD.

LEARNING OBJECTIVE

To highlight the reliability and unique utility of intraoperative ECoG and demonstrate the correlation between ECoG correction and symptom improvement for SSCD repair.

DESIRED RESULT

To report subjective and objective outcomes following SSCD repair and encourage adoption of intraoperative ECoG monitoring.

LEVEL OF EVIDENCE

Level V.

INDICATE IRB OR IACUC

IRB review considers this study exempt (HUM00169949).

OUP accepted manuscript

The superior semicircular canal dehiscence is a vestibular disease recognized condition in recent years, and surgical therapy has been modeling itself over the years to ensure the control of vestibular symptoms and auditory symptoms. In this case series, the authors have experienced an intervention aimed at closing the superior semicircular canal dehiscence through the insertion of bone paté between the meninx and the residual middle cranial fossa bone wall. Seven patients underwent this intervention, they reported an improvement in all vestibular and auditory symptoms, and hearing threshold remained stable. Despite the small sample size, the difference was significant in the control of dizziness and the reduction of pulsatile tinnitus. The technique described in this article allows the control of symptoms in superior semicircular canal dehiscence, and it is a type of surgery familiar to the otosurgeon and easily replicable as it involves a modified mastoidectomy. More data are needed.

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.

Surgical treatments of superior semicircular canal dehiscence: A single-centre experience in 63 cases

OBJECTIVE

Different procedures have been described to treat superior canal dehiscence. The present study aims to describe the results obtained with middle fossa approach, transmastoid approach, and round window reinforcement in a large series of patients.

METHODS AND DESIGN

In this single-center retrospective study, we report the results of the procedures performed between 2006 and 2019 using the three main surgical approaches, middle fossa approach (MFA), transmastoid approach (TMA), and round window reinforcement (RWR). The outcome on cardinal cochlear and vestibular symptoms, audiometric results, and changes in cervical vestibular evoked myogenic potentials (cVEMPs) were analyzed. The patients were also interviewed 12 months to 13 years post-treatment to establish their overall satisfaction following surgery.

RESULTS

Sixty-three patients were divided into three groups: 42 MFA; 12 RWR; 9 TMA. Postsurgical control rates exceeded 80% for the majority of symptoms in the MFA and TMA groups, and ranged from 11.1% to 83.3% for the RWR group. Over 90% of MFA or TMA patients and 60% of the RWR cohort were satisfied overall with their treatment. Hearing thresholds were intact following surgery in the MFA and TMA groups. There was one case of profound postoperative deafness in the RWR group.

CONCLUSION

MFA and TMA are both safe and effective techniques in the treatment of disabling SSCD. Since MFA is the more invasive technique, we suggest that TMA should be proposed as first-line treatment, temporal bone anatomy permitting. RWR outcomes are more variable in term of symptomatic control, and this option could be offered to patients at risk under general anesthesia.

LEVEL OF EVIDENCE

Level 4 evidence.

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.

Superior Semicircular Canal Dehiscence by Superior Petrosal Sinus: Proposal for Classification

OBJECTIVES

This study aimed to present 3 different clinical stages in patients presenting with superior semicircular canal dehiscence (SSCD) by the superior petrosal sinus (SPS). A specific 3-class classification based on clinical, radiological, and audio-vestibular arguments is proposed.

MATERIALS AND METHODS

We retrospectively compared clinical and radiological findings in 3 patients with different degrees of audio-vestibular dysfunction in whom the imagery evocated the diagnosis of SSCD by SPS. Imaging sensitivity was improved by combining inner ear high-resolution computed tomography (HRCT) scan and magnetic resonance imaging in fusion, allowing us to compare and corroborate clinical and audio-vestibular findings in each case with the imagery.

RESULTS

HRCT and 3T inner ear fusion imaging highlighted a direct contact and/or compression between SPS and the membranous superior semicircular canal (SSC). We propose a new classification of SSCD by SPS. Class "A" corresponds to an HRCT image with a "cookie bite" and thin bone still covering the SSC. Class "B" corresponds to a "cookie bite" image with confirmed contact between the SPS wall and the membranous SSC in MRI labyrinthine sequences. Class "C" type corresponds to a "cookie bite" image, contact, and obvious compression of the membranous SSC by SPS on MRI sequences.

CONCLUSION

Anatomical systematization is needed for daily practice. This classification of SSCD by SPS would contribute to a better understanding of the wide variety and variability in the occurrence and onset of symptoms.

Wideband tympanometry in ears with superior canal dehiscence before and after surgical correction

OBJECTIVES

Wideband tympanometry (WBT) has been shown to be sensitive to mechanical changes in the ear. This study investigated the effect of surgical correction of superior canal dehiscence (SCD) on WBT (i.e. absorbance and middle ear resonance frequency) compared to those on common surgical outcomes such as symptom resolution, vestibular evoked myogenic potentials (VEMP), and hearing thresholds.

STUDY SAMPLE AND STUDY DESIGN

Seven patients (eight ears with SCD) who underwent surgical correction of SCD underwent WBT in addition to pure-tone audiometry and VEMP assessment.

RESULTS

Postoperatively, all ears showed normalised/decreased absorbance at low frequencies and slightly enhanced absorbance in the middle frequency range (7/8 ears). The middle ear resonance frequency, which was initially lower than normal in most patients, increased in 6/8 operated ears, and decreased in two ears with no/partial symptom relief. In comparison, complete symptom control was observed in 6/8 operated ears, VEMP amplitudes reduced or normalised in all ears, and hearing thresholds remained stable or improved in 6/8 ears and worsened in two ears.

CONCLUSIONS

Surgery seems to change the response to WBT in patients with SCD. The results of WBT may represent mechanical changes induced by SCD, and should be considered when evaluating surgical outcomes.

Audiologic Outcomes After Oval and Round Window Reinforcement Surgery

INTRODUCTION

Oval window (OW) and round window (RW) reinforcement surgery has been used for symptomatic treatment of multiple clinical entities, most commonly perilymphatic fistula and superior semicircular canal dehiscence. Owing to the theoretical acoustically negative effect of stiffening the windows, there has been concern of an unfavorable effect on audiologic outcomes due to the procedure. The purpose of this study is to specifically evaluate audiologic outcomes after OW and RW reinforcement.

METHODS

A retrospective review of patients undergoing transcanal OW or RW reinforcement was completed. Patients were evaluated both as a total group and as two groups separated into "third window" and "two-window" groups based on their specific diagnosis. Primary outcomes included changes in individual pure-tone thresholds, pure-tone average (PTA), air-bone gap, speech reception threshold (SRT), and word recognition scores (WRS) between the preoperative and postoperative groups.

RESULTS

Seventy-one patients were included in the study. The combined cohort demonstrated a significant postoperative 2.75 dB increase in the air conduction hearing level at 4000 Hz (p < 0.05). This was almost entirely accounted for by a 2.18 dB increase in the air-bone gap at this frequency (p < 0.05). There were no significant changes in PTA, SRT, or WRS between in the combined group or in the subgroup analysis.

CONCLUSION

OW and RW tissue reinforcement resulted in a statistically significant but likely clinically insignificant decrease in hearing at the 4000 Hz frequency. There was no worsening of PTA, WRS, or SRT.

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.

Underwater Endoscopic Repair of Superior Canal Dehiscence

: Superior canal dehiscence (SCD) is a bony defect of the superior semicircular canal (SCC). Patients with SCD Syndrome (SCDS) may experience symptoms such as aural fullness, pulsatile tinnitus, hyperacusis, autophony, or pressure or noise-induced vertigo . The defect can be repaired in various ways, but there is potential for loss of perilymphatic fluid during transmastoid approaches that could result in postoperative sensorineural hearing loss . We hypothesize that if the procedure were performed "underwater" in balanced salt solution (BSS), loss of perilymphatic fluid would be minimized. CASE REPORT:: A 55-year-old male presented with right-sided autophony, pulsatile tinnitus, and hyperacusis. Audiometric testing demonstrated a low-frequency airbone gap and a supranormal bone-conduction threshold at 4 kHz. Ocular VEMP responses were increased amplitude. Temporal bone imaging revealed a SCC dehiscence.The patient was taken to the operating room for an underwater, endoscopic repair of the SCC using a transmastoid approach. A cortical mastoidectomy was performed using Landmarx image navigation. BSS filled the mastoid and a 0-degree endoscope with endoscrub was used to see the SCC underwater. The SCC was entered near the ampullated end with a bur. A stepwise plugging process included applying strips of wet and dried fascia and bone dust. The non-ampullated end was similarly plugged. BSS was suctioned, and under microscopic visualization, labyrinthotomies were capped with bone chips. The patient tolerated the procedure well and was discharged the next day. There was no sensorineural hearing loss postoperatively. CONCLUSION:: SCDS may be addressed surgically using multiple approaches. An underwater endoscopic repair of the SCC may be safe and effective surgical treatment.SDC video link: http://links.lww.com/MAO/A808.

Outcomes after mini-craniotomy middle fossa approach combined with mastoidectomy for lateral skull base defects

PURPOSE

Controversy exists regarding the ideal approach for repair of lateral skull base defects. Our goal is to report the outcomes following middle cranial fossa (MCF) mini-craniotomy combined with mastoidectomy for patients with superior semicircular canal dehiscence (SSCD), spontaneous cerebrospinal fluid (CSF) leak, and cholesteatoma.

MATERIALS AND METHODS

A retrospective database from chart review was formed consisting of 97 patients who met surgical criteria: SSCD, spontaneous CSF leak, and cholesteatoma. Mini-craniotomy MCF approach (<4 × 2 cm in size) combined with mastoidectomy was performed. All patients were admitted directly to the ICU postoperatively. Multiple factors were assessed, including need for revision surgery, duration of surgery, length of post-operative stay, and hospital readmission.

RESULTS

Average surgery time was 110 min with no intraoperative complications. The average length of hospitalization was 2 days with an average ICU stay of 1 day. There were no neurologic complications; however, there were 3 inpatient complications (3%) which included 1 patient (1%) that had wound breakdown and 2 patients (2%) that had severe post-operative vertigo. A total of 8 patients (8%) required revision surgery and these were primarily for SSCD. The 30-day readmission rate was 3%.

CONCLUSION

In the current series, all patients that underwent mini-craniotomy MCF surgery combined with mastoidectomy had minimal complications, short surgical time, limited hospital stay, low revision surgery rate and few hospital readmissions. This combined approach offers superior visualization of lateral skull base defects without the morbidity and risk typically associated with traditional, extensive MCF surgery.

Methodological Quality of Systematic Reviews and Meta-analyses Published in High-Impact Otolaryngology Journals

OBJECTIVE

To assess the methodological quality of intervention-focused systematic reviews (SRs) and meta-analyses (MAs) published in high-impact otolaryngology journals.

DATA SOURCES

Ovid Medline, Embase, and Cochrane Library.

REVIEW METHODS

A comprehensive search was performed for SR and MA citations from 2012 to 2017 in the 10 highest impact factor otolaryngology journals. Abstracts were screened to identify published manuscripts in which the authors indicated clearly that they were performing an SR or MA. Applying a modified typology of reviews, 4 reviewers characterized the review type as SR, MA, or another review type. A simplified version of the AMSTAR 2 (A MeaSurement Tool to Assess systematic Reviews 2) tool was used to assess the reporting and methodological quality of the SRs and MAs that were focused on interventions.

RESULTS

Search and abstract screening generated 499 manuscripts that identified themselves as performing an SR or MA. A substantial number (85/499, 17%) were review types other than SRs or MAs, including 34 (7%) that were literature reviews. In total, 236 SRs and MAs focused on interventions. Over 50% of these SRs and MAs had weaknesses in at least 3 of the 16 items in the AMSTAR 2, and over 40% had weaknesses in at least 2 of the 7 critical domains. Ninety-nine percent of SRs and MAs provided critically low confidence in the results of the reviews.

CONCLUSION

Intervention-focused SRs and MAs published in high-impact otolaryngology journals have important methodological limitations that diminish confidence in the results of these reviews.

A Basis for Standardizing Superior Semicircular Canal Dehiscence Management

OBJECTIVES

(1) To determine how otologic/neurotologic surgeons counsel patients with superior semicircular canal dehiscence (SSCD). (2) To understand the plethora of presenting symptoms associated with SSCD and appropriate management. (3) To suggest appropriate management; oftentimes avoiding surgery.

METHODS

This was a survey study of both community and academic physicians. A 23-question survey was distributed to all members of the American Neurotological (ANS) and American Otologic Societies (AOS) via email in the Fall of 2018. A total of 54 responses were received from a possible pool of 279 for a response rate of 19.4%. Inferences were made about the population through sample proportions and confidence intervals.

RESULTS

All respondents use computed tomography (CT) in diagnosing SSCD and 11.1% use CT exclusively. Cervical vestibular evoked myogenic potential (VEMP; 77.8%) are used more often than ocular VEMPs (38.9%). Magnetic resonance imaging (7.4%) is used infrequently; 96.3% of surgeons surveyed have seen patients with SSCD on imaging that are asymptomatic. Following surgical treatment, respondents reported balance issues and mild-to-moderate high-frequency sensorineural hearing loss (88.4%); 32.6% reported that the majority (>50%) of their patients needed further intervention after surgery, typically aggressive vestibular rehabilitation.

CONCLUSIONS

There is a discrepancy in the systematic approach to SSCD between both the surgeons and the published literature. Patients with SSCD on ultra-high-resolution CT may have myriad symptoms while others are asymptomatic, and surgery may lead to additional complications. We will present a methodical recommendation to assist in the management of patients with SSCD depending upon their symptoms. This may improve patient selection, counseling, and outcomes.

Systematic Review of Round Window Operations for the Treatment of Superior Semicircular Canal Dehiscence

A review of the literature is presented to consider the role of round window (RW) operations in superior semicircular canal dehiscence (SSCD). Primary (PubMed) and secondary sources (TRIP, Cochrane database, Best Practice, and PubMed Clinical Queries) were used to identify relevant studies. Four original studies (three case series and one case report) were identified. All were retrospective reviews and used a number of subjective and objective outcome measures to assess the efficacy of a minimally invasive, transmeatal approach to perform RW surgery for SSCD. The current evidence suggesting that RW operations for SSCD are unlikely to replace more established surgical procedures as first-line treatment may be appropriate in a select group of patients. Further multicenter, randomized controlled trials are required to establish their efficacy in patients with SSCD.

Comparison of Transmastoid and Middle Fossa Approaches for Superior Canal Dehiscence Repair: A Multi-institutional Study

OBJECTIVE

To compare outcomes for patients undergoing a transmastoid approach versus a middle fossa craniotomy approach with plugging and/or resurfacing for repair of superior semicircular canal dehiscence. Outcome measures include symptom resolution, hearing, operative time, hospital stay, complications, and revision rates.

STUDY DESIGN

Multicenter retrospective comparative cohort study.

SETTINGS

Three tertiary neurotology centers.

SUBJECTS AND METHODS

All adult patients undergoing repair for superior canal dehiscence between 2006 and 2017 at 3 neurotology centers were included. Demographics and otologic history collected by chart review. Imaging, audiometric data, and vestibular evoked myogenic potential measurements were also collected for analysis.

RESULTS

A total of 68 patients (74 ears) were included in the study. Twenty-one patients underwent middle fossa craniotomy repair (mean age, 47.9 years), and 47 underwent transmastoid repair (mean age, 48.0 years). There were no significant differences in age or sex distribution between the groups. The transmastoid group experienced a significantly shorter duration of hospitalization and lower recurrence rate as compared with the middle fossa craniotomy group (3.8% vs 33%). Both groups experienced improvement in noise-induced vertigo, autophony, pulsatile tinnitus, and nonspecific vertigo. There was no significant difference among symptom resolution between groups. Additionally, there was no significant difference in audiometric outcomes between the groups.

CONCLUSION

Both the transmastoid approach and the middle fossa craniotomy approach for repair of superior canal dehiscence offer symptom resolution with minimal risk. The transmastoid approach was associated with shorter hospital stays and lower recurrence rate as compared with the middle fossa craniotomy approach.

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 Gopen-Yang Superior Semicircular Canal Dehiscence Questionnaire: development and validation of a clinical questionnaire to assess subjective symptoms in patients undergoing surgical repair of superior semicircular canal dehiscence

OBJECTIVE

To characterise subjective symptoms in patients undergoing surgical repair of superior semicircular canal dehiscence.

METHODS

Questionnaires assessing symptom severity and impact on function and quality of life were administered to patients before superior semicircular canal dehiscence surgery, between June 2011 and March 2016. Questionnaire sections included general quality of life, internal amplified sounds, dizziness and tinnitus, with scores of 0-100 points.

RESULTS

Twenty-three patients completed the questionnaire before surgery. Section scores (mean±standard deviation) were: 38.2 ± 25.2 for general quality of life, 52.5 ± 23.9 for internal amplified sounds, 35.1 ± 28.8 for dizziness, 33.3 ± 30.7 for tinnitus, and 39.8 ± 22.2 for the composite score. Cronbach's α statistic averaged 0.93 (range, 0.84-0.97) across section scores, and 0.83 for the composite score.

CONCLUSION

The Gopen-Yang Superior Semicircular Canal Dehiscence Questionnaire provides a holistic, patient-centred characterisation of superior semicircular canal dehiscence symptoms. Internal consistency analysis validated the questionnaire and provided a quantitative framework for further optimisation in the clinical setting.

Anterior Canal benign paroxysmal positional Vertigo following surgical Management of superior canal dehiscence

OBJECTIVE

Benign paroxysmal positional vertigo (BPPV) is a common post-surgical finding in patients managed for superior semicircular canal dehiscence (SSCD). The posterior semicircular canal has been reported as the involved canal in the majority of cases of post-surgical BPPV, with only two cases reported of lateral canal involvement. The objective of this report is to present a case in which an anterior semicircular canal BPPV response was identified in a patient following surgical management for SSCD.

METHOD

This case report presents an adult with residual dizziness following surgical management of SSCD and vestibular rehabilitation therapy (VRT). During subsequent evaluation of vestibular function, a transient and torsional, down-beating nystagmus was provoked along with vertigo during Dix-Hallpike positioning to the right. This was consistent with BPPV affecting the left superior (anterior) semicircular canal.

RESULTS

The patient was treated with a repositioning maneuver to manage anterior semicircular canal BPPV and no nystagmus response was recorded with post-repositioning Dix-Hallpike test. Review of radiographic images, obtained prior to vestibular function testing, showed a hyperintensity in the area of the left anterior semicircular canal ampulla. It was felt this was likely a bone chip from the SSCD repair that was pushing against the ampulla with further mobile debris within the canal.

CONCLUSION

It is reported that BPPV is a common complication in patients surgically managed for SSCD. Posterior semicircular canal BPPV is reported most often, with a couple of cases of lateral semicircular canal BPPV also reported. As far as we are aware, the current case represents the first report of anterior semicircular canal BPPV in this type of patient.

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.

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.