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

Surgical decision-making in superior canal dehiscence syndrome with concomitant otosclerosis

OBJECTIVE

The diagnosis and management of Superior Canal Dehiscence Syndrome (SCDS) with concomitant otosclerosis can be a challenge. Otosclerosis can mask SCDS symptoms and stapes surgery may reveal or exacerbate vestibular symptoms. Our aim is to present four cases of SCDS with concomitant otosclerosis and thereby informing the reader about the possibility of this dual occurrence and its implications for treatment.

CASES

Four patients with SCDS and concomitant otosclerosis are presented. Two patients underwent surgical treatment for both SCDS and otosclerosis and two patients opted for conservative management.

OUTCOMES

The main differences between surgically and non-surgically treated cases are the presence of autophony and pressure-induced vertigo and a more severe experience of symptoms in surgically treated cases. Surgically treated cases achieved a sizeable reduction in postoperative air-bone gap and resolution of vestibular symptoms.

CONCLUSION

The subjective severity of symptoms in combination with shared decision-making is key in determining the appropriate treatment plan for SCDS and concomitant otosclerosis.

Analysis of postoperative effects of different semicircular canal surgical technique in patients with labyrinthine fistulas

Objective

Different semicircular canal surgery techniques have been used to treat patients with labyrinthine fistulas caused by middle ear cholesteatoma. This study evaluated postoperative hearing and vestibular function after various semicircular canal surgeries.

Materials and methods

In group 1, from January 2008 to December 2014, 29 patients with middle ear cholesteatoma complicated by labyrinthine fistulas were treated with surgery involving covering the fistulas with simple fascia. In group 2, from January 2015 to October 2021, 36 patients with middle ear cholesteatoma complicated by labyrinthine fistulas were included. Cholesteatomas on the surface of type I labyrinthine fistulas were cleaned using the “under water technique” and capped with a “sandwich” composed of fascia, bone meal, and fascia. Cholesteatomas on the surface of type II and III fistulas were cleaned using the “under water technique,” and the labyrinthine fistula was plugged with a “pie” composed of fascia, bone meal, and fascia, and then covered with bone wax.

Results

Some patients with labyrinthine fistulas in group 1 exhibited symptoms of vertigo after surgery. In group 2 Patients with type II labyrinthine fistulas experienced short-term vertigo after semicircular canal occlusion, but no cases of vertigo were reported during long-term follow-up. “sandwich.” In patients with type II labyrinthine fistulas, the semicircular canal occlusion influenced postoperative hearing improvement. However, postoperative patient hearing was still superior to preoperative hearing.

Conclusion

The surface of type I labyrinthine fistulas should be capped by a “sandwich” composed of fascia, bone meal, and fascia. Type II and III labyrinthine fistulas should be plugged with a “pie” composed of fascia, bone meal, and fascia, covered with bone wax.

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.

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

Background

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

Objective

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

Methods

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

Results

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

Conclusion

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

Supplementary Information

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

Prospective Analysis of an Evidence-Based Symptom Set in Superior Canal Dehiscence Syndrome

INTRODUCTION

Superior canal dehiscence syndrome (SCDS) is characterized by a defect in the bone overlying the superior semicircular canal. This third mobile window generates an abnormal low-impedance pathway for sound/pressure transmission into the inner ear resulting in the characteristic symptoms.

OBJECTIVE

To perform a prospective analysis of symptoms in patients with SCDS.

METHODS

An aggregated symptom set was studied prospectively and compared with a healthy control group. The 31 items inquired about the presence and severity of symptoms. Initial comparison between both groups was performed using the Kolmogorov-Smirnov test and nonparametric Mann-Whitney U test. For analysis of the internal consistency, the Cronbach's alpha coefficient was determined. Finally, the prevalence of symptoms obtained in the present study was compared to the prevalence of symptoms obtained as part of a recent retrospective systematic review.

RESULTS

Responses from the 29 patients with SCDS in the case group and the 58 healthy controls were not normally distributed. Those with SCDS had a higher prevalence and more severe symptoms for almost all items. The Cronbach's alpha coefficient of 0.969 indicates an excellent internal consistency. The prospective prevalence of most symptoms was higher than the retrospective prevalence reported earlier.

CONCLUSIONS

SCDS causes a variety of vestibular and auditory symptoms. This prospective study demonstrates that their prevalence and severity are higher than reported previously. This symptom set demonstrates excellent internal consistency and will serve as a foundation toward developing a disease-specific patient-reported outcome measure for SCDS.

LEVEL OF EVIDENCE

NA.

Impact of Superior Canal Dehiscence Syndrome on Health Utility Values: A Prospective Case-Control Study

Introduction: Superior canal dehiscence syndrome (SCDS) is a condition characterized by a defect in the bone overlying the superior semicircular canal, creating a third mobile window into the inner ear. Patients can experience disabling symptoms and opt for surgical management. Limited data are available on the impact of SCDS on health-related quality of life (HRQoL) and disease-specific HRQoL more specifically.

Objective: To perform a prospective analysis on generic HRQoL in SCDS patients compared to healthy age-matched controls.

Methods: A prospective study was performed on patients diagnosed with SCDS and who did not undergo reconstructive surgery yet. Patients were recruited between November 2017 and January 2020 and asked to complete the Health Utility Index (HUI) Mark 2 (HUI2)/Mark 3 (HUI3) questionnaire. For the control group, age-matched participants without otovestibular pathology or other chronic pathology were recruited. The multi-attribute utility function (MAUF) score was calculated for the HUI2 and HUI3. Results of both groups were compared using the Mann-Whitney U test.

Results: A total of 20 patients completed the questionnaire. Age ranged from 37 to 79 years with a mean age of 56 years (45% males and 55% females). The control group consisted of 20 participants with a mean age of 56.4 years and ranged from 37 to 82 years (35% males and 65% females). For the case group, median HUI2 MAUF score was 0.75 and median HUI3 MAUF score was 0.65. For the control group, the median scores were 0.88 and 0.86 respectively. There was a statistically significant difference for both HUI2 (p = 0.024) and HUI3 (p = 0.011). SCDS patients had a worse generic HRQoL than age-matched healthy controls. One patient with unilateral SCDS had a negative HUI3 MAUF score (−0.07), indicating a health-state worse than death.

Conclusion: SCDS patients have significantly lower health utility values than an age-matched control group. This confirms the negative impact of SCDS on generic HRQoL, even when using an instrument that is not designed to be disease-specific but to assess health state in general. These data can be useful to compare impact on HRQoL among diseases.

Audiometric and cVEMP Thresholds Show Little Correlation With Symptoms in Superior Semicircular Canal Dehiscence Syndrome

OBJECTIVE

Evaluate the relationship between objective audiometric and vestibular tests and patient symptoms in superior canal dehiscence (SCD) syndrome.

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary care center.

PATIENTS

Ninety-eight patients with SCD, preoperative threshold audiograms, cervical vestibular evoked myogenic potential (cVEMP) thresholds, and computed tomography (CT) imaging were included. Clinical reports were reviewed for self-reported SCD symptoms. Twenty-five patients completed the Hearing Handicap Inventory (HHI), Dizziness Handicap Inventory (DHI), Autophony Index (AI), and the 36-item Short Form Survey (SF-36).

MAIN OUTCOME MEASURES

Correlations between preoperative low-frequency air-bone gap (ABG), cVEMP thresholds, and symptoms (including HHI, DHI, AI, and SF-36). Symptoms included hearing loss, aural fullness, autophony, hyperacusis, tinnitus, vertigo, imbalance and sound-, pressure and exercise provoked dizziness. Secondary outcome measure: Correlations between changes of objective and subjective measures before and after surgery.

RESULTS

Patients who reported hearing loss had larger ABGs at 250 Hz than patients without subjective hearing loss (p = 0.001). ABGs and cVEMP thresholds did not correlate with any other symptom. No significant correlation was found between ABG or cVEMP threshold and the HHI, DHI, AI or Health Utility Value (derived from the SF-36 quality of life score). Following SCD surgery, ABG decreased (p < 0.001), cVEMP thresholds increased (p < 0.001) and overall symptoms, handicap scores and quality-of-life improved; however, there was no significant relationship between these measures.

CONCLUSION

While threshold audiometry and cVEMP are important tools to diagnose SCD and monitor surgical outcomes, these measures showed no significant correlation with vestibular and most auditory symptoms or their severity.