Outcomes of Transmastoid Surgery for Superior Semicircular Canal Dehiscence Syndrome

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.

Insights from therapeutic strategies in superior canal dehiscence syndrome: is there anything beyond surgical treatment?

INTRODUCTION

Superior semicircular canal dehiscence syndrome (SCDS) is a clinical syndrome that can cause instability, vertigo, fullness, tinnitus, autophony, hearing loss (HL), Tullio phenomenon, or Hennebert's sign. Historically, surgery has been the primary treatment reported in the literature, although some medical treatments may also be proposed. This study aims to comprehensively characterize SCDS in a large series of patients from clinical, auditory, and vestibular perspectives, and explore medical alternatives to conventional surgical treatments by comparing their results and evolution.

METHODS

A retrospective observational study was designed in a tertiary care center. Audiovestibular tests evaluated included pure-tone audiometry (PTA), VEMPs, video head impulse test (vHIT), and CT imaging. Improvement was assessed over a follow-up period of up to 6 months for seven cardinal symptoms to verify the efficacy of the proposed treatments.

RESULTS

71 subjects with SCDS and a mean age of 51.20 ± 12.22 years were included in the study. The most common symptom found in our sample was instability in 31 patients (43.66%), followed by aural fullness or tinnitus in 29 subjects (40.85%). 36 patients (43.66%) received medical treatment, with 28 of them (77.78%) showing symptom reduction. Surgical repair was indicated in five patients, with all showing symptom improvement. Statistically significant improvement (p < 0.05) was observed, particularly with surgical treatment and acetazolamide, in both symptoms and objective tests such as pure-tone audiometry and VEMPs.

CONCLUSION

SCDS shows significant similarities with other otic capsule dehiscences. It is essential to perform VEMPs and CT scans to complete the diagnosis, which is usually accompanied by clearly recognizable clinical criteria. Surgery for SCDS is effective, safe, and without complications. However, in cases where symptoms are mild to moderate, addressing this condition with medical treatment using diuretics such as acetazolamide has shown promising results.

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.

Evaluation of Superior Semicircular Canal Dehiscence Anatomical Location and Clinical Outcomes: A Single Institution's Experience

BACKGROUND

Superior semicircular canal dehiscence (SSCD) is becoming increasingly recognized as a pathology underlying various auditory and vestibular complaints. To date, our understanding of the pathology has yet to attribute specific symptoms to the anatomic location of dehiscence in patients with SSCD. This study aims to address this issue by evaluating the relationship between symptomatology and anatomic location of dehiscence.

METHODS

A single-institution retrospective review of SSCD patients was performed. Information was collected on patient demographics, symptomatology, and anatomic location of dehiscence. High-resolution computed tomography scans of the temporal bones were used to categorize the anatomic SSCD location into 1 of 3 groups: anterior limb, apex, and posterior limb. Lastly, we performed statistical analysis to determine the degree of association between each of the various perioperative factors and anatomic SSCD location.

RESULTS

We studied 54 patients in total (32 women, 22 men). Mean age at diagnosis was 53 years (range: 20-82 years) and mean follow-up length was 5.5 months (range: 0.03-27.0 months). The most common anatomical location of superior semicircular canal dehiscence was the apex, which was seen in 68.5% of cases. While preoperative symptomatology was similar among the 3 cohorts, those with apical dehiscences had a significantly higher rate of postoperative improvement of autophony (P = 0.03), aural fullness (P = 0.03), and tinnitus (P = 0.05) as compared to their counterparts.

CONCLUSIONS

Although our results do not support an association between preoperative characteristics-including symptomatology-and anatomic SSCD location, our findings do suggest that apical dehiscences are associated with greater postoperative symptomatic resolution.

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.

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.

Superior Semicircular Canal Dehiscence Revision Surgery Outcomes: A Single Institution's Experience

BACKGROUND

Superior semicircular canal dehiscence (SSCD) is an abnormality of the otic capsule, which normally overlies the superior semicircular canal. Surgical management is indicated in patients with persistent and debilitating symptoms. Given the complexity of the disease, there are patients who experience less favorable surgical outcomes and require revision surgery. The purpose of this study was to report to the rate of postoperative symptomatic improvement in patients who required revision surgery.

METHODS

A retrospective analysis of patients undergoing SSCD surgical repair at a single institution was performed. Information on patient demographics, primary and secondary surgical approaches, surgical outcomes, and follow-up length was collected.

RESULTS

Seventeen patients underwent 20 revision surgeries. There were eleven (65%) females and six (35%) males. Mean age of the cohorts was 50 years (range 30-68 years), and mean follow-up length was 6.8 months (range 0.1-31.1 months). Cerebrospinal fluid leak was noted in 67% of cases. The greatest postoperative symptomatic resolution was reported in oscillopsia (100%), headache (100%), and internal sound amplification (71%), while the least postoperative symptomatic resolution was reported in tinnitus (42%), aural fullness (40%), and dizziness (29%).

CONCLUSIONS

Revision surgery can provide symptomatic improvement in select SSCD patients; however, patients should be cautioned about the possibility of less favorable outcomes than in index surgery. Revision surgeries are associated with a considerably higher rate of perioperative cerebrospinal fluid leak.

Superior Semicircular Canal Dehiscence Outcomes in a Consecutive Series of 229 Surgical Repairs With Middle Cranial Fossa Craniotomy

BACKGROUND

Superior semicircular canal dehiscence (SSCD) is the appearance of a third mobile window between the middle fossa and the superior semicircular canal. Surgical management is indicated in patients with persistent and debilitating symptoms. The purpose of this study was to evaluate the association between preoperative variables that may impact postoperative symptomatic resolution.

METHODS

A single-institution retrospective analysis was performed on patients who were surgically treated for SSCD. Patients were divided to different cohorts based on unilateral or bilateral nature of the disease. A P value <0.05 was considered statistically significant.

RESULTS

A total of 229 surgical repairs were analyzed. Mean age was 51 years (± 7.8 years), and 55.9% of patients were female. All cohorts were similar with respect to baseline demographics. The most commonly reported preoperative symptoms were tinnitus, dizziness, and autophony. The greatest symptomatic resolution was seen in autophony, internal sound amplification, hyperacusis, and oscillopsia. The unilateral SSCD cohort had significantly higher improvement of autophony (P = 0.003), aural fullness (P = 0.05), tinnitus (P = 0.006), hearing loss (P = 0.02), dizziness (P = 0.006), and headache (P = 0.007), compared with the bilateral SSCD cohorts. Among patients with bilateral disease, those with unilateral surgery reported greater symptomatic resolution with respect to hyperacusis (P = 0.03), hearing loss (P = 0.02), dizziness (P = 0.03), and disequilibrium (P < 0.001), than those with bilateral operations.

CONCLUSIONS

Surgical management of SSCD leads to high rates of postoperative symptomatic improvement. Patients with unilateral SSCD benefit greater symptomatic resolution compared to those with bilateral pathology.

Quality of life outcomes after transmastoid plugging of superior semicircular canal dehiscence

PURPOSE

This study was performed to evaluate the effectiveness and impact on quality of life in patients undergoing plugging of superior semicircular canal dehiscence using the transmastoid approach.

MATERIALS AND METHODS

Retrospective chart review with prospective outcomes assessment, using validated quantitative scoring systems, was performed on 10 patients (23-76 years) who underwent transmastoid plugging of superior semicircular canal dehiscence between February 2014 and February 2018 at a tertiary referral center. Pre-operative and post-operative autophony and vertigo were measured by The Autophony Index and the Dizziness Handicap Index. Overall quality of life following intervention was measured by the Glasgow Benefit Inventory. Subjective improvement, audiological changes, and subjective quality of life changes were also recorded.

RESULTS

A significant reduction in the total Dizziness Handicap Index was seen following transmastoid repair of superior semicircular canal dehiscence (p = 0.0078). This was also evident when subgroup analysis of the Dizziness Handicap Index was performed, as physical (p = 0.0273), emotional (p = 0.0078), and functional subgroups were all significantly reduced (p = 0.0117). Autophony was also significantly reduced following intervention (p = 0.0312). Overall quality of life was seen to be improved following surgery as measured by the Glasgow Benefit Inventory (p = 0.0345).

CONCLUSION

Our data suggest that transmastoid plugging of a dehiscence in the superior semicircular canal is a safe and effective means of improving autophony, dizziness and overall quality of life in these patients. We believe that these results should be taken into consideration in discussions regarding surgical approach for patients who are contemplating this procedure.

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.

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.

Long-Term Patient-Reported Outcomes After Surgery for Superior Canal Dehiscence Syndrome

OBJECTIVE

Evaluate the long-term patient-reported outcomes of surgery for superior canal dehiscence syndrome (SCDS).

STUDY DESIGN

Cross-sectional survey.

SETTING

Tertiary referral center.

PATIENTS

Adults who have undergone surgery for SCDS with at least 1 year since surgery.

MAIN OUTCOME MEASURE(S)

Primary outcome: change in symptoms that led to surgery.

SECONDARY OUTCOMES

change in 11 SCDS-associated symptoms, change in psychosocial metrics, and willingness to recommend surgery to friends with SCDS.

RESULTS

Ninety-three (43%) respondents completed the survey with mean (SD) time since surgery of 5.3 (3.6) years. Ninety-five percent of respondents reported the symptoms that led them to have surgery were "somewhat better," "much better," or "completely cured." Those with unilateral symptoms were more likely to report improvement than those with bilateral symptoms. There was no difference between those with short (1-5 yr) versus long (5-20 yr) follow-up. Each of the SCDS-associated symptoms showed significant improvement. The largest improvements were for autophony, pulsatile tinnitus, audible bodily sounds, and sensitivity to loud sound. Headaches, imbalance, dizziness, and brain fog showed the least improvements. Most patients reported improvements in quality of life, mood, and ability to function at work and socially. Ninety-five percent of patients would recommend SCDS surgery.

CONCLUSIONS

Respondents demonstrated durable improvements in the symptoms that led them to have surgery. Auditory symptoms had the greatest improvements. Headaches, imbalance, dizziness, and brain fog showed the least improvements. Nearly, all patients would recommend SCDS surgery to others. These results can be used to counsel patients regarding the lasting benefits of surgery for SCDS.

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.

Superior Canal Dehiscence Syndrome: Lessons from the First 20 Years

Superior semicircular canal dehiscence syndrome was first reported by Lloyd Minor and colleagues in 1998. Patients with a dehiscence in the bone overlying the superior semicircular canal experience symptoms of pressure or sound-induced vertigo, bone conduction hyperacusis, and pulsatile tinnitus. The initial series of patients were diagnosed based on common symptoms, a physical examination finding of eye movements in the plane of the superior semicircular canal when ear canal pressure or loud tones were applied to the ear, and high-resolution computed tomography imaging demonstrating a dehiscence in the bone over the superior semicircular canal. Research productivity directed at understanding better methods for diagnosing and treating this condition has substantially increased over the last two decades. We now have a sound understanding of the pathophysiology of third mobile window syndromes, higher resolution imaging protocols, and several sensitive and specific diagnostic tests. Furthermore, we have a treatment (surgical occlusion of the superior semicircular canal) that has demonstrated efficacy. This review will highlight some of the fundamental insights gained in SCDS, propose diagnostic criteria, and discuss future research directions.