Semicircular Canal Research Articles

Cochlear Implantation in Patients With Osteolytic Labyrinthitis: A Case Series.

To describe the rare process of osteolytic labyrinthitis, previously referred to as labyrinthine sequestrum, which involves progressive obliteration of the bony and membranous labyrinth with eventual supplantation with soft tissue and, in some cases, bony sequestrum. Three patients with diverse presentations of osteolytic labyrinthitis from two tertiary care academic medical centers. Case series report analyzing the relevant clinical, radiologic, pathologic, and surgical data on our patients with osteolytic labyrinthitis and comparing these index cases to the existing literature. We describe the varying image findings seen in osteolytic labyrinthitis on computed tomography and magnetic resonance imaging. Also, we report successful surgical intervention and hearing rehabilitation with cochlear implantation in patients with osteolytic labyrinthitis. Our three patients presented with profound sudden sensorineural hearing loss and vertigo consistent with labyrinthitis. None of the three patients had a history of chronic otitis media. Imaging workup revealed varying degrees of erosion to the otic capsule bone demonstrating the spectrum of disease seen in osteolytic labyrinthitis. Although two cases showed osteolytic changes to the semicircular canals and vestibule, the first case revealed frank bony sequestrum within the obliterated labyrinth. The three cases were taken for surgical debridement and cochlear implantation. We propose the new term, osteolytic labyrinthitis-previously referred to as labyrinthine sequestrum-to describe the rare spectrum of disease characterized by destruction of the osseous and membranous labyrinth and potential supplantation with bony sequestrum. Cochlear implantation is a viable option in selected patients with osteolytic labyrinthitis.

Endoscopic-Assisted Cochlear Implantation in Far Advanced Otosclerosis.

To evaluate the effectiveness of cochlear implantation (CI) in case of far advanced otosclerosis and to evaluate the value of using intraoperative otoendoscopy to facilitate the identification of the round window membrane and the scala tympani without the need to remove the posterior canal wall or to perform a subtotal petrosectomy. Retrospective case-series study. Tertiary academic CI center. This study was conducted on patients with far advanced otosclerosis who underwent endoscopic-assisted CI between January 2010 and June 2020 at the same CI center. The minimum follow-up period was 2 years after surgery. Fourteen patients were included in the study. Ten patients had undergone a previous stapedotomy. Electrode insertion in the scala tympani was successfully accomplished in all cases included in the study. There was a statistically significant improvement in pure-tone average and speech discrimination scores in all cases of the study group (p < 0.0001). There were no statistically significant differences in postoperative pure-tone average or speech discrimination scores between cases with and without cochlear ossification or between cases with and without a previous stapedotomy (p > 0.05). Endoscopic-assisted CI is an effective option for hearing restoration in patients with far advanced otosclerosis. Otoendoscopy can facilitate visualization and access to the scala tympani without the need to remove the posterior canal wall or to perform a subtotal petrosectomy.

Age dependent vestibulo-ocular reflex gain in video head impulse test among normal Indians.

Determination of the normative data of Vestibulo-Ocular Reflex gain using VHIT of all three semicircular canals (anterior, posterior, horizontal) on both sides in different age groups is of interest. This is an observational study comprised of 10 healthy individuals in each decade from less than 10 years to 80 years of both sexes making a total of 80. The study was done using the equipment SYNAPSYS VHIT ULMER with Software EVOLUTION 3.0. Mean VOR gain of each decade for all the semicircular canals is calculated and they are compared using ANOVA (Analysis of variance). In our study, percentage of patients with overt saccades is nil. Hence, in our study, the occurrence of covert saccades was insignificant as compared to the above studies. Age dependent VOR gain in normal individuals did not have any significance in our study of 80 patients performed by video head impulse test. VOR gain in our study is not affected by age. Normative data for different age groups obtained compared among different age groups showing no significant difference in Mean VOR gain. The normative values of VOR gain can be compared to patients with dizziness thus helping in determining any vestibular loss.

Measuring absorbed energy in the human auditory system using finite element models: A comparison with experimental results.

There are different ways to analyze energy absorbance (EA) in the human auditory system. In previous research, we developed a complete finite element model (FEM) of the human auditory system. In this current work, the external auditory canal (EAC), middle ear, and inner ear (spiral cochlea, vestibule, and semi-circular canals) were modelled based on human temporal bone histological sections. Multiple acoustic, structure, and fluid-coupled analyses were conducted using the FEM to perform harmonic analyses in the 0.1-10 kHz range. Once the FEM had been validated with published experimental data, its numerical results were used to calculate the EA or energy reflected (ER) by the tympanic membrane. This EA was also measured in clinical audiology tests which were used as a diagnostic parameter. A mathematical approach was developed to calculate the EA and ER, with numerical and experimental results showing adequate correlation up to 1 kHz. Another published FEM had adapted its boundary conditions to replicate experimental results. Here, we recalculated those numerical results by applying the natural boundary conditions of human hearing and found that the results almost totally agreed with our FEM. This boundary problem is frequent and problematic in experimental hearing test protocols: the more invasive they are, the more the results are affected. One of the main objectives of using FEMs is to explore how the experimental test conditions influence the results. Further work will still be required to uncover the relationship between middle ear structures and EA to clarify how to best use FEMs. Moreover, the FEM boundary conditions must be more representative in future work to ensure their adequate interpretation.

Changes of video head impulse test before and after translabyrinthectomy in patients with acoustic neuroma.

Acoustic neuroma (AN) is a benign tumor that usually affects a patient's hearing and balance function. For the screening and diagnosis of AN, the traditional approach mainly relies on audiological examination and magnetic resonance imaging (MRI), often ignoring the importance of vestibular function assessment in the affected area. As an emerging method of vestibular function detection, video head impulse test (vHIT) has been widely used in clinic, but research on its use in AN diagnosis is relatively limited. This study aims to explore the value of vHIT in the diagnosis of AN, vestibular dysfunction assessment, and postoperative compensation establishment in unilateral AN patients undergoing unilateral AN resection through labyrinthine approach. This retrospective study was conducted on 27 AN patients who underwent unilateral AN resection via labyrinthine approach from October 2020 to March 2022 in the Department of Otolaryngology-Head and Neck Surgery, the Second Xiangya Hospital, Central South University. vHIT was performed 1 week before surgery to assess vestibular function, pure tone audiometry (PTA) was used to assess hearing level, and ear MRI was used to assess tumor size. Follow-up vHIT was conducted at 1 week, 1 month, 6 months, and 1 year post-surgery. The correlation of vHIT with hearing and tumor size was analyzed. Preoperative vHIT showed that the posterior semicircular canal on the affected side was the most common semicircular canal with reduced vestibulo-ocular reflex (VOR) gain. There was a correlation between the VOR gain of vHIT on the affected side and the hearing level (r=-0.47, P<0.05) or tumor size (r=-0.54, P<0.01). The results of vHIT on the affected side showed that the hearing level and mean VOR gain of the anterior semicircular canal increased slightly with time, and the amplitude and saccade percentage of the dominant saccades of the 3 semicircular canals increased, while the latency time decreased, with the most obvious changes occurring 1 week post-surgery. vHIT can effectively monitor the changes of vestibular function in AN patients before and after surgery and has application value in assisting the diagnosis of vestibular dysfunction in AN patients.

Congenital Unilateral Hearing Loss from Cochlear Nerve Canal Stenosis

A 2-month-old baby girl presented with a failed neonatal otoacoustic emission (OAE) hearing screening in the left ear. Combined Auditory Brainstem Response/Auditory Steady-State Response (ABR/ASSR) testing confirmed the presence of a unilateral left moderate to severe hearing loss. No Joint Committee on Infant Hearing (JCIH) risk factors for early childhood hearing loss1 were identified. She subsequently underwent computed tomography (CT) of the temporal bones to determine the presence of any inner ear malformation. No abnormalities of the internal auditory canal, cochlea, semicircular canals and ossicles were noted by the radiologist, and the study was officially reported as a “normal temporal bone CT scan.” Independent review of the CT imaging revealed the presence of a visually apparent disparity in the width of the cochlear nerve canals. (Figure 1) Measurement of the cochlear nerve canal width in the axial plane parallel to the infraorbitomeatal line2 using the length measurement tool in the DICOM imaging software (RadiAnt DICOM Viewer, Version 2024.1, Medixant) indicated a cochlear nerve canal width of 2.18 mm on the right and 1.02 mm on the left. (Figure 2) Applying the suggested cutoff point of 1.2 mm as described by Lin et al.,2 we identified the presence of left cochlear nerve canal stenosis as the etiology of the congenital unilateral hearing loss. The cochlear nerve canal, which has also been referred to as the bony canal for the cochlear nerve (BCNC), cochlear aperture, and cochlear fosette, is the bony transition point between the internal auditory canal and the cochlear modiolus. A relationship between a hypoplastic cochlear nerve canal and congenital sensorineural hearing loss was first suggested by Fatterpekar et al. in 2000.3 Subsequent studies confirmed the association between cochlear nerve canal stenosis and sensorineural hearing loss that ranges from near-normal to profound, with a statistically significant relationship between the degree of hearing loss and the degree of stenosis.4 Various cutoff points to define stenosis of the cochlear nerve canal have been identified in the medical literature. These cutoff points range from 1.2 mm to 1.7 mm when the canal width is measured in the axial plane.2 This particular case demonstrated clear-cut evidence of cochlear nerve canal stenosis, as it satisfied the smallest cutoff criteria (&lt; 1.2 mm) seen in the medical literature. The identification of cochlear nerve canal stenosis as the cause of congenital sensorineural hearing loss is important not only from a diagnostic point, but also from a prognostic perspective. Cochlear nerve deficiency has been noted to be highly prevalent among pediatric patients with cochlear nerve canal stenosis,5 and this has significant negative implications in relation to rehabilitation with external hearing devices and cochlear implants.

Comparing Approaches for Repair of Superior Semicircular Canal Dehiscence.

Compare outcomes for subjects who underwent middle cranial fossa (MCF) or transmastoid (TM) repair of superior semicircular canal dehiscence (SSCD). Retrospective cohort study. Quaternary-care, academic neurotology practice. 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. 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). 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.

Morphometric Analysis of the Retrolabyrinthine Approach to the Posterior Fossa

The retrolabyrinthine approach provides shorter working distance and less cerebellar retraction compared with the retrosigmoid approach to the internal acoustic canal (IAC) and cerebellopontine angle cistern. However, exposure of the ventral surface of the brainstem and petroclival region may be restricted. Trautmann's triangle (TT), an area intimately related to this region, demonstrates significant anatomical variability, which may adversely affect the ease of the approach. The aim of this study is to evaluate anatomic parameters of the posterior fossa that may anticipate a challenging situation in approaching the IAC and the petroclival region through the retrolabyrinthine approach. It was performed a radioanatomic analysis of 75 cerebral angiotomography exams to identify parameters that could potentially reduce areas of surgical exposure. Large variations were observed in the area of exposure of the TT (553%) and the height of the jugular bulb (234%). Shorter distances from the sigmoid sinus to the posterior semicircular canal and high-riding jugular bulb were associated with smaller areas of exposure. Dominant and laterally positioned sigmoid sinuses and less pneumatized mastoids were associated with potentially unfavorable conditions, including a narrower angle of attack to the IAC. Increased petrous slopes and petroclival angles were associated with smaller petroclival areas and shallower clival depths. This study of the posterior fossa reveals remarkable anatomic variation in the region. These findings should be taken into consideration during the preoperative planning of retrolabyrinthine approaches in order to offer safer and more effective surgical procedures.

Comparison of Depth of Mastoid Antrum on High Resolution Computed Tomography and Per Operatively in Cases Undergoing Mastoidectomy.

To compare the depth of mastoid antrum on High Resolution Computed Tomography and per operatively in cases undergoing mastoidectomy. This prospective observational study was done in a tertiary care Army Hospital with 35 patients meriting cortical mastoidectomy surgery. The patients underwent HRCT of temporal bone as a routine pre-operative work up, where depth of mastoid antrum was measured from dome of lateral semicircular canal to outer cortex of temporal bone. Depth was also recorded per-operatively with the help of measuring scale. Measurements were correlated and data was analysed statistically. There were 12 male patients and 23 females. 6 patients were < 3years of age and 29 above. Study included 29 cases of Chronic Otitis Media and 6 of Bilateral Congenital Sensorineural Hearing Loss. Mean depth of mastoid antrum was 1.625cm ± 0.228 on HRCT, and 1.651cm ± 0.245 per-operatively. Depths of mastoid antrum on HRCT and per operatively amongst paediatrics as well as adult cases were comparable, but were more than the standard depth of 1cm in 5 (82.3%) paediatrics cases and ˃1.5cm in 24 (82.9%) adult patients. In absence of Koerner's Septum, mean HRCT depth was 1.60cm ± SD 0.23 and per operatively was 1.63cm ± SD 0.21; whereas in its presence mean HRCT depth was 1.84cm ± SD 0.069 and per-operatively was 1.85cm ± SD 0.42. Significant difference in depth was noted between adults and children, and between the cases with or without Koerner's Septum. However, difference in depth was not significant when compared between different genders, laterality of disease or disease pathology.

Toward Automating Diagnosis of Middle- and Inner-ear Mechanical Pathologies With a Wideband Absorbance Regression Model.

During an initial diagnostic assessment of an ear with normal otoscopic exam, it can be difficult to determine the specific pathology if there is a mechanical lesion. The audiogram can inform of a conductive hearing loss but not the underlying cause. For example, audiograms can be similar between the inner-ear condition superior canal dehiscence (SCD) and the middle-ear lesion stapes fixation (SF), despite differences in pathologies and sites of lesion. To gain mechanical information, wideband tympanometry (WBT) can be easily performed noninvasively. Absorbance, the most common WBT metric, is related to the absorbed sound energy and can provide information about specific mechanical pathologies. However, absorbance measurements are challenging to analyze and interpret. This study develops a prototype classification method to automate diagnostic estimates. Three predictive models are considered: one to identify ears with SCD versus SF, another to identify SCD versus normal, and finally, a three-way classification model to differentiate among SCD, SF, and normal ears. Absorbance was measured in ears with SCD and SF as well as normal ears at both tympanometric peak pressure (TPP) and 0 daPa. Characteristic impedance was estimated by two methods: the conventional method (based on a constant ear-canal area) and the surge method, which estimates ear-canal area acoustically.Classification models using multivariate logistic regression predicted the probability of each condition. To quantify expected performance, the condition with the highest probability was selected as the likely diagnosis. Model features included: absorbance-only, air-bone gap (ABG)-only, and absorbance+ABG. Absorbance was transformed into principal components of absorbance to reduce the dimensionality of the data and avoid collinearity. To minimize overfitting, regularization, controlled by a parameter lambda, was introduced into the regression. Average ABG across multiple frequencies was a single feature.Model performance was optimized by adjusting the number of principal components, the magnitude of lambda, and the frequencies included in the ABG average. Finally, model performances using absorbance at TPP versus 0 daPa, and using the surge method versus constant ear-canal area were compared. To estimate model performance on a population unknown by the model, the regression model was repeatedly trained on 70% of the data and validated on the remaining 30%. Cross-validation with randomized training/validation splits was repeated 1000 times. The model differentiating between SCD and SF based on absorbance-only feature resulted in sensitivities of 77% for SCD and 82% for SF. Combining absorbance+ABG improved sensitivities to 96% and 97%. Differentiating between SCD and normal using absorbance-only provided SCD sensitivity of 40%, which improved to 89% by absorbance+ABG. A three-way model using absorbance-only correctly classified 31% of SCD, 20% of SF and 81% of normal ears. Absorbance+ABG improved sensitivities to 82% for SCD, 97% for SF and 98% for normal. In general, classification performance was better using absorbance at TPP than at 0 daPa. The combination of wideband absorbance and ABG as features for a multivariate logistic regression model can provide good diagnostic estimates for mechanical ear pathologies at initial assessment. Such diagnostic automation can enable faster workup and increase efficiency of resources.

Vestibular Disorders Limited to the Vertical Semicircular Canals.

Introduction The advent of the video head impulse test (vHIT) enables the study of each one of the six semicircular canals. In the present study, certain patients present disorders related only to the vertical semicircular canals, and they were carefully evaluated. Objective To investigate vestibular disorders limited to the vertical semicircular canals. Methods In total, 9,891 patients were submitted to the vHIT in our clinic; 26 (2.63%) of them, 11 men and 15 women, showed reduced vestibulo-ocular reflex (VOR) limited to the vertical canals. All of these patients had vestibular symptoms. Results These patients presented different disorders of the vestibular system, and ten of them presented vestibular neuritis. Conclusion Now, vestibular disorders limited the vertical canals can be evaluated through the vHIT. These disorders, however, may relate do different labyrinthine diseases.

Superior semicircular canal dehiscence postoperative outcomes: a case series of 350 repairs

BackgroundSuperior Semicircular Canal Dehiscence (SSCD) is a dehiscence of the otic capsule which normally lies over the superior semicircular canal. This database constitutes the largest series of SSCD patients to date.ObjectiveTo determine what preoperative factors, if any, contribute to postoperative outcomes and evaluate symptom resolution in a large SSCD patient cohort.MethodsA single-institution, retrospective chart review collected patient demographics, intraoperative findings, and pre-and postoperative symptoms. Fisher's exact t-test was performed for unpaired categorical variables, with a significance level of p < 0.05.Results350 SSCD repairs were performed. The median age was 52 years (range: 17—86 years, ± 6.4 years), and the median follow-up duration was 4.6 months (range: 0.03—59.5 months, ± 6.8 months). Preoperative hearing loss was significantly associated with female sex (p = 0.0028). The most reported preoperative symptoms were tinnitus (77.4%), dizziness (74.0%), autophony (66.3%), amplification (63.7%), and disequilibrium (62.6%). Between patients who received unilateral versus bilateral SSCD repair, the greatest postoperative symptomatic resolution was seen in autophony (74.9%, p < 0.001), amplification (77.3%, p = 0.00027), hyperacusis (77.4%, p = 0.023), hearing (62.9%, p = 0.0063), and dizziness (54.6%, p < 0.001) for patients with unilateral SSCD repair.ConclusionSurgical repair via the middle cranial fossa approach can significantly resolve auditory, vestibular, and neurological symptoms of patients with SSCD. Although this is one of the largest single-institution SSCD studies to date, future multi-institutional, prospective studies would be beneficial to validate these results.

Canal cholesteatoma: an alarming sequela of congenital aural atresia

Congenital aural atresia is an external ear malformation that may have diverse clinical presentations ranging from conductive hearing loss to the formation of canal cholesteatoma. Canal cholesteatoma, once developed can aggressively erode the bony boundaries of the middle ear cleft and lead to dangerous complications. Here we present the clinical outlook and surgical management of a child with congenital aural atresia with extensive canal cholesteatoma and complications. A twelve-year-old girl with congenital aural atresia and microtia of the right ear presented with right sided infra-auricular abscess with overlying skin ulceration. She also had right sided grade 4 facial paralysis. Pure tone audiometry revealed severe conductive hearing loss on the right side. In contrast, a high-resolution computed tomography scan showed extensive soft tissue on the right side completely destroying the posterior bony canal wall, with erosion of the sigmoid plate and the mastoid tip. We performed a right sided modified radical mastoidectomy and canal atresia repair along with the removal of the necrotic and infected tissues. The little girl recovered uneventfully with improved facial nerve function and without any sign of cholesteatoma recidivism. In congenital aural atresia, early surgical intervention is the key to prevent the formation of canal cholesteatoma and subsequent complications.

Assessing the Vestibulo-ocular Reflex of Contralesional Sides According to Head Impulse Velocity Utilizing the Video Head Impulse Test in Patients with Vestibular Neuritis.

There is a lack of comparative studies examining changes in vestibulo-ocular reflex (VOR) gain with head velocity in the video head impulse test (vHIT) of patients with vestibular neuritis (VN). Thus, the purpose of present study was to identify the effect of head impulse velocity on the gain of the VOR during the vHIT in patients with VN. Head impulse velocities ranging from 100%-200°/s [158.08 ± 23.00°/s in the horizontal canal (HC), 124.88 ± 14.80°/s in the anterior canal (AC), and 122.92 ± 14.26°/s in the posterior canal (PC) were used during vHIT trials of 32 patients with VN. Differences in VOR gain on the ipsilesional and contralesional sides according to head velocity were analyzed. The mean VOR gains in ipsilesional side were decreased to 0.47 in the HC and 0.56 in the AC, leading to marked asymmetry compared to the contralesional side; PC gain was relatively preserved at 0.82 in the ipsilesional side. The mean head impulse velocity applied during vHIT trials in each semicircular canal plane did not differ bilaterally. On the contralesional side, VOR gain was negatively correlated with head impulse velocity (R2=0.25, P=.004 in HC; R2=0.17, P=.021 in AC; R2=0.24, P=.005 in PC), while VOR gain on the ipsilesional sides of the HC and AC was not. Head impulse velocity may have a differential impact on VOR gain, depending on the degree of deficit. Increasing head velocity in vHIT may be considered to identify subtle deficits on the contralesional side of patients with VN.

Management of recurrent benign paroxysmal positional vertigo.

Benign paroxysmal positional vertigo is the most common episodic vestibular disorder, although it is often quiescent by the time patients visit a specialist clinic, making the diagnosis difficult to confirm. Patients fear the consequences of a relapse and it is not clear what follow up should be provided. This evaluation reviewed the results of an open access pathway that offered priority appointments to patients with a history of positional vertigo. In total, 664 patients were included in the analysis, 52 per cent of whom had unconfirmed benign paroxysmal positional vertigo. Open follow up improved diagnostic rates by approximately 40 per cent. The rate of benign paroxysmal positional vertigo recurrence was 34 per cent in patients with follow up of at least one year, 41 per cent with follow up of one to two years, and 53 per cent with follow up of two years or more. One in five recurrences occurred in a different semi-circular canal. These results suggest that specialist follow up is required for management of recurrent benign paroxysmal positional vertigo.

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

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

Anatomical Analysis of the Eustachian Tube in the Temporal Bone Through the Middle Fossa Window.

This cadaveric anatomical study aimed to explore precise morphometric measurements of the eustachian tube (ET) and adjacent structures in the middle cranial fossa, focusing on identifying reliable surgical landmarks when traditional markers are compromised due to tumors or trauma. Twenty-two temporal bones from 11 adult cadavers (mean age: 75.70 ± 13.75 yr, range: 40-90 yr; sex: 5 females and 6 males) were dissected bilaterally. Surgical tools, including an operation microscope, endoscope, and digital caliper, were used for meticulous measurements. Parameters such as ET dimensions, distances between key points, and relevant angles were quantified, ensuring precise anatomical data. ET width at the foramen spinosum (FS) level, the midline level, and the eustachian orifice level were measured as 2.18 ± 0.68, 2.42 ± 0.70, and 2.30 ± 0.74 mm, respectively. The distances from the zygomatic root (ZR) to FS, ET, superior semicircular canal (SSC), and internal carotid artery (ICA) were 29.61 ± 2.56, 23.28 ± 2.61, 26.53 ± 2.56, and 32.61 ± 3.69 mm, respectively. The angles between SSC-ZR-ICA and FS-ZR-ICA were measured as 36.57 ± 10.32 and 13.63 ± 3.72 degrees, respectively. No statistical difference was found between right-left or male-female measurements ( p > 0.05). The present study offers invaluable insights for neurotological surgeons performing middle fossa approaches. ET and ZR may serve as crucial reference points, enhancing surgical orientation and minimizing risks during complex procedures. These precise anatomical data may empower surgeons, ensuring safer and more confident middle cranial fossa operations, even in challenging clinical scenarios.

Comparing Video Head Impulse Testing With Rotary Chair in Pediatric Patients: A Controlled Trial.

To investigate the efficacy of video head impulse testing (VHIT) in detecting vestibular loss in pediatric patients with abnormal rotary chair testing, compared to a control group with normal rotary chair testing. Prospective, nonrandomized, controlled trial. Pediatric vestibular program at tertiary level children's hospital. Patients 3 to 18 years of age were recruited to undergo VHIT and rotary chair testing between September 2015 and November 2022. VHIT results were compared between an experimental group of 23 patients with vestibular symptoms and abnormal rotary chair testing results versus a control group of 14 patients without vestibular symptoms and with normal rotary chair testing results. The experimental group demonstrated reduced mean VHIT gain for the lateral semicircular canals (right = 0.83; left = 0.75) relative to the control group (right = 1.04, P = .005; left = 0.98, P < .001), but there was no significant difference between groups in superior and posterior canal responses. Among controls, there were no significant differences in mean gain values for each canal plane between age groups (3-7, 8-12, and 13-18 years) or between genders. A VHIT lateral canal gain value <0.85 and/or corrective saccades demonstrated 100% specificity and 100% positive predictive value for detecting vestibular loss on rotary chair, but only 69.6% sensitivity and 66.7% negative predictive value. VHIT is a useful test for detecting impairment of the lateral semicircular canals in children, though its sensitivity is limited relative to rotary chair. Its role in detecting vertical canal dysfunction in pediatric patients may be more limited and warrants further study.

Video head impulse test in subacute and chronic stroke survivors: new perspectives for implementation of assessment in rehabilitation.

The Video Head Impulse Test (vHIT) is a safe and reliable assessment of peripheral vestibular function. Many studies tested its accuracy in clinical settings for differential diagnosis and quantification of the vestibulo-oculomotor reflex (VOR) in various disorders. However, the results of its application after lesions of the CNS are discordant and have never been studied in rehabilitation. This study aims to assess the VOR performance in a sample of stroke survivors. This is a cross-sectional study on 36 subacute and chronic stroke survivors; only persons with first-ever stroke and able to walk independently, even with supervision, were included. We performed VOR assessments for each semicircular canal by vHIT and balance assessments by the Berg Balance Scale and the MiniBESTest scale. Two hundred and sixteen semicircular canals were assessed using the Head Impulse paradigm (in both the vertical and horizontal planes), while 72 semicircular canals were assessed using the Suppressed Head Impulse paradigm (horizontal plane). There was a high prevalence of participants with dysfunctional canals, particularly for the left anterior and right posterior canals, which were each prevalent in more than one-third of our sample. Furthermore, 16 persons showed an isolated canal dysfunction. The mean VOR gain for the vertical canals had confidence intervals out of the normal values (0.74-0.91 right anterior; 0.74-0.82 right posterior; 0.73-0.87 left anterior). Our findings suggest that peripheral vestibular function may be impaired in people with stroke; asystematic assessment in a rehabilitation setting could allow a more personalized and patient-centred approach.

Temporal bone marrow of the rat and its connections to the inner ear.

Calvarial bone marrow has been found to be central in the brain immune response, being connected to the dura through channels which allow leukocyte trafficking. Temporal bone marrow is thought to play important roles in relation to the inner ear, but is still largely uncharacterized, given this bone complex anatomy. We characterized the geometry and connectivity of rat temporal bone marrow using lightsheet imaging of cleared samples and microCT. Bone marrow was identified in cleared tissue by cellular content (and in particular by the presence of megakaryocytes); since air-filled cavities are absent in rodents, marrow clusters could be recognized in microCT scans by their geometry. In cleared petrosal bone, autofluorescence allowed delineation of the otic capsule layers. Within the endochondral layer, bone marrow was observed in association to the cochlear base and vestibule, and to the cochlear apex. Cochlear apex endochondral marrow (CAEM) was a separated cluster from the remaining endochondral marrow, which was therefore defined as "vestibular endochondral marrow" (VEM). A much larger marrow island (petrosal non-endochondral marrow, PNEM) extended outside the otic capsule surrounding semicircular canal arms. PNEM was mainly connected to the dura, through bone channels similar to those of calvarial bone, and only a few channels were directed toward the canal periosteum. On the contrary, endochondral bone marrow was well connected to the labyrinth through vascular loops (directed to the spiral ligament for CAEM and to the bony labyrinth periosteum for VEM), and to dural sinuses. In addition, CAEM was also connected to the tensor tympani fossa of the middle ear and VEM to the endolymphatic sac. Endochondral marrow was made up of small lobules connected to each other and to other structures by channels lined by elongated macrophages, whereas PNEM displayed larger lobules connected by channels with a sparse macrophage population. Our data suggest that the rat inner ear is surrounded by bone marrow at the junctions with middle ear and brain, most likely with "customs" role, restricting pathogen spread; a second marrow network with different structural features is found within the endochondral bone layer of the otic capsule and may play different functional roles.