Manual neuronavigation for superior semicircular canal dehiscence surgery

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

A Rare Case of Large Skull Base Meningioma Mimicking Otitis Media with Effusion

A 48-year-old woman presented with unilateral hearing loss and tinnitus for three years associated with middle ear effusion. Previous treatments, including antibiotics, corticoids, and transtympanic tube, were ineffective. Otomicroscopy showed a greyish retrotympanic mass associated with middle ear effusion. High resolution CT scan of the mastoid was in favor of chronic oto-mastoiditis without any evidence of tegmen dehiscence. Surgical exploration revealed a polypoid greyish mass filling the tympanic cavity. Histological examination postoperatively revealed a meningothelial meningioma. Postoperative magnetic resonance imaging (MRI) was obtained and showed a large skull base meningioma, extending from the clivus anteriorly to the porus acusticus posteriorly with middle ear invasion. After discussion with the multidisciplinary tumor board, it was managed by stereotactic radiotherapy due to the high surgical associated neurovascular risks. In conclusion, middle ear meningioma, although still a rare presentation, should be suspected in the presence of atypical chronic OME

Reply to Hornibrook, J. Comment on “Tabet et al. Vestibular Migraine versus Méniere’s Disease: Diagnostic Utility of Electrocochleography. <i>Audiol. Res.</i> 2023, <i>13</i>, 12–22”

We appreciate the comments made by Hornibrook (2024) [...

Reliability of Monothermal Caloric Test as Screening Test of Vestibular System

This retrospective study completed at a tertiary care center aimed to assess the monothermal caloric test (MCT) as a screening test, using the bithermal caloric test (BCT) as a reference. Additionally, it attempts to measure the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of a fixed inter-auricular difference (IAD) value for both cold and warm stimuli using water irrigation. Medical records of 259 patients referred for vestibular symptoms who underwent BCT with water irrigation were reviewed. Patients with bilateral vestibular weakness and caloric tests using air irrigation were excluded. BCT showed 40.9% unilateral weakness. Two formulas were used to determine the monothermal caloric asymmetry (MCA-1 and MCA-2). The measurement of agreement Kappa between the two formulas in comparison with BCT revealed moderate agreement at 0.54 and 0.53 for hot and cold stimulation, respectively. The monothermal warm stimulating test (MWST) using MCA-2 showed better results, with a sensitivity of 80%, specificity of 91%, PPV of 83.1%, and NPV of 89.2%. Thirty-four patients had horizontal spontaneous nystagmus (HSN) with a mean velocity of 2.25°/s. These patients showed better sensitivity but lower specificity after adjustment of HSN using the MCA-2 formula at warm temperatures. Therefore, they should complete the caloric test with cold irrigation to perform the BCT. MCT is efficient as a screening test if the warm stimulus is used with the MCA-2 formula fixed at 25%. If present, HSNs should be adjusted. Negative IAD (normal) in the absence or presence of adjusted HSN or slow-phase eye velocity ≤ 6°/s at each right and left warm stimulation should be accomplished by the BCT

Hearing Outcomes Following Endolymphatic Duct Blockage Surgery and Factors Associated with Improved Audition at Two Years Follow-Up

Objective: To evaluate hearing outcomes at 2 years post endolymphatic duct blockage (EDB) surgery, with an analysis of factors that may predict hearing improvement. Study Design: Retrospective comparative study. Setting: Tertiary care center. Subjects: Definite Ménière’s Disease (MD) patients undergoing EDB for refractory disease. Methods: Chart review was conducted to assign cases to one of the three hearing outcome groups (deteriorated, stable, and improved). All cases that met our inclusion criteria were selected. Preoperative data collected were audiograms, bithermal caloric tests, preoperative vertigo episodes, history of previous ear surgery for Ménière, intratympanic steroid injections (ITS) and intraoperative endolymphatic sac (ELS) tear or opening. Postoperative data collected at 24 months were audiograms, vertigo episodes and bithermal caloric testing. Results: Preoperative vertigo episodes, caloric paresis and history of surgery, ITS injections or ELS integrity, as well as postoperative vertigo class distribution and caloric paresis changes were not different between our groups. Preoperative word recognition score (WRS) was lowest in the improved hearing group (p = 0.032). The persistence of tinnitus at 2 years postoperatively was associated with deteriorated hearing (p = 0.033). Conclusions: There are no strong predictors of hearing improvement on presentation pre-EDB, but low preoperative WRS may be the best estimator available. Therefore, ablative interventions should be considered very carefully in patients presenting with low WRS, as they may benefit more from EDB; there is a fair chance of a good hearing outcome with EDB surgery. Persistence of tinnitus can reflect deteriorating audition. Vertigo control and hearing preservation are independent outcomes of EDB surgery, making it desirable as an early intervention for refractory MD cases

Vestibular Migraine versus M&eacute;niere&rsquo;s Disease: Diagnostic Utility of Electrocochleography

Objectives: The diagnostic criteria for vestibular migraine (VM) and M&eacute;niere&rsquo;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 &lt; 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 &lt; 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