Video Head Impulse Test Demonstrates a Residual Function after Plugging of Dehiscent Superior Semicircular Canal.

OBJECTIVE: Plugging a symptomatic dehiscent superior semicircular canal (SSCC) often leads to a nonfunctional postoperative canal. However, in some instances, a residual function has been described. This study attempts to describe what factors may lead to such residual function. STUDY DESIGN: Retrospective study. SETTING: Tertiary referral center. PATIENTS: Thirty-five patients with confirmed SSCC dehiscence. INTERVENTION: Video head impulse test was conducted pre- and postoperatively to assess any difference in the function of the SSCC. MAIN OUTCOME MEASURES: Mean gain and pathological saccades were recorded according to well-established thresholds along with dehiscence length and location to evaluate any associations to residual canal function. RESULTS: When comparing preoperative to postoperative SSCC abnormal gains, a significant increase was observed after plugging ( p = 0.023). This also held true when abnormal gain and pathologic saccades were taken together ( p < 0.001). Interestingly, 55.3% of patients were observed to remain with a residual SSCC function 4 months postoperatively even with a clinical improvement. Of these, 47.6% had normal gain with pathologic saccades, 38.1% had an abnormal gain without pathologic saccades, and 14.3% had normal gain without pathologic saccades (normal function). Preoperatively, SSCC abnormal gain was associated with a larger dehiscence length mean ( p = 0.002). Anterosuperior located dehiscences were also associated with a larger dehiscence length mean ( p = 0.037). A residual SSCC function after plugging was associated with a shorter dehiscence length regardless of location ( p = 0.058). CONCLUSION: Dehiscence length and location may be useful in predicting disease symptomatology preoperatively and canals function recovery after plugging. These factors could be used as indicators for preoperative counseling and long-term management.

Vestibular Migraine versus Méniere's Disease: Diagnostic Utility of Electrocochleography.

Objectives: The diagnostic criteria for vestibular migraine (VM) and Méniere's disease (MD) present an important overlap, which leads to a difficult diagnosis in patients presenting with headache, vertigo, hearing loss, ear fullness, and tinnitus. The objective of our study is to determine whether the area-under-the-curve ratio of the summating potentials (SP) and action potentials (AP) curves on electrocochleography (ECoG) helps differentiate VM from MD with or without the use of the well-established clinical criteria. Method: A retrospective review of patients filling either VM or MD criteria was undertaken between September 2015 and December 2018. All patients underwent ECoG before the introduction of anti-migraine therapy. The prediction of symptom improvement between the clinical criteria and ECoG results was compared by using the Vertigo Symptom Scale. Results: In total, 119 patients were included. An overlap of 36% exists between patients filling VM and MD criteria. Clinical criteria alone did not demonstrate a significant prediction of symptom response to anti-migraine therapy (VM 83%, MD 51%; p = 0.10). However, ECoG results alone did demonstrate adequate prediction (VM 94%, MD 32%; p < 0.001). A negative ECoG result combined with the clinical criteria of VM (100% symptom improvement) was shown to be more predictive of treatment response when compared to clinical criteria alone (83% symptom improvement) (p = 0.017). Finally, when used in patients filling both the VM and MD criteria (VMMD), ECoG was able to predict symptom improvement, thus better differentiating both diseases (normal ECoG: 95%, abnormal ECoG 29%; p < 0.001). Conclusion: Combining VM criteria with normal ECoG using the AUC ratio seems superior in predicting adequate symptom improvement than VM criteria alone.

Investigating Performance of cVEMP and oVEMP in the Identification of Superior Canal Dehiscence in Relation to Dehiscence Location and Size.

Compare the sensitivity and specificity of cVEMP (500 Hz), oVEMP (500 Hz and 4 kHz) in the identification of SSCD. A secondary objective was to identify the influence of dehiscence size and location on cVEMP and oVEMP responses. Methods: Individuals with unilateral (n = 16) and bilateral (n = 10) scan confirmed SSCD were assessed using air-conducted cVEMP and oVEMP Results: For cVEMP, an amplitude cutoff of 286.9 µV or a threshold cutoff of 67.5 dBnHL revealed, respectively, a sensitivity of 75% and 70.6% and a specificity of 69.4% and 100%. For oVEMP (500 Hz), an amplitude cutoff of 10.8 µV or a threshold cutoff of 77.5 dBnHL revealed a sensitivity of 83.33% and a specificity of 87.5% and 80%, respectively. oVEMP (4 kHz), an amplitude cutoff of 3.1 µV, revealed a high specificity of 100% but a low sensitivity of 47.2%. A positive correlation was noted between the length of the SSCD and the cVEMP and oVEMP (500 Hz) thresholds and cVEMP amplitude. Conclusions: Our results support the use of oVEMP in the identification of SSCD. The presence of oVEMP (500 Hz) with an amplitude higher or equal to 10.8 µV, a threshold lower or equal to 77.5 dBnHL or oVEMP (4 kHz) amplitude of 3.1 µV represents the most useful to identify SSCD.

Predictable prosthesis length on a high-resolution CT scan before a stapedotomy.

OBJECTIVE: (1) To assess the correlation between preoperative high-resolution CT (HRCT) imaging measurement from the long process of the incus to the footplate and the length of intraoperative selected prosthesis. (2) To determine if HRCT has a predictive value of prolapsed facial nerve during stapedotomy. MATERIALS AND METHODS: We evaluated in our tertiary care center, in a retrospective case series, 94 patients undergoing primary stapedotomy. Preoperative temporal bone HRCT scans were reformatted in the plane of the stapes to measure on the same section the distance between the long process of the incus and the footplate. Measurement was performed by otolaryngology resident and neurotologist. We analyze the interobserver correlation and the mean length measured on the HRCT to the selected prosthesis size intraoperatively. RESULTS: Mean HRCT measurement of the incus long process/footplate distance assessed by the otolaryngology resident and neurotologist was 4.34 and 4.38 mm, respectively. Interobserver correlation was statistically significant [intraclass correlation coefficient (ICC) of 0.679 (p < 0.001)]. Mean selected prosthesis length intraoperatively was 4.36 mm. Correlation between the mean selected length prosthesis and the mean HRCT measurement was also statistically significant [ICC of 0.791 (p < 0.001)]. Postoperatively, a statistical improvement was shown in air conduction (p < 0.001), bone conduction (p < 0.001) and air-bone gap reduction (p < 0.001). 2 cases of facial nerve covering one-half of the oval window were identified by HRCT and confirmed intraoperatively. CONCLUSION: HRCT is a valuable tool to predict preoperatively the length of the stapedotomy prosthesis. Moreover, it might be helpful to identify a potential prolapsed facial nerve, to confirm the diagnosis of otosclerosis and to rule out other abnormalities. Ultimately, it may optimize the stapedotomy procedure planning.