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Objectives: The aim of our study to contribute to the field of morphometrics by including measurements of the SAC and SAF and their distances from surrounding structures, particularly for surgeons involved in retrosigmoid approach for internal acoustic meatus tumor surgery and cerebellopontine angle surgery. Although there is limited information in the literature regarding the role of the subarcuate fossa (SAF) and subarcuate canal (SAC), it has been suggested that the SAC may be a potential pathway for infection from the middle ear to the posterior cranial fossa, and cerebellar abscesses may have this origin., Methods: For the images of our study, computerized tomography images of 118 individuals (59 females and 59 males) between the ages of 18-65 who applied to Bayındır Health Group., Results: The width of the cranial opening of the subarcuate canal was determined as 44 ± 0.54 mm, width of the labyrinth opening of the subarcuate canal was determined as 60 ± 0.42 mm, Length of the subarcuate canal was determined as 8.79 ± 2.31 mm, width of the subarcuate canal was determined as 5.54 ± 1.75 mm, and depth of subarcuate fossa was determined as 1.67 ± 0.69 mm. The distance of the cranial opening of the subarcuate canal to the superior semicircular canal (SSC-SAC/C) was measured as 5.33 ± 1.81 mm, The distance of the labyrinth opening of the subarcuate canal to the superior semicircular canal (SSC-SAC/L) was measured as 3.90 ± .98 mm, length of the petrous part of the temporal bone medial to the anterior semicircular canal measured from the apex to the SSCD (PLM) was measured as 33.56 ± 0.42 mm. No statistically significant differences were found between the right and left sides., Conclusions: The morphometric measurements obtained in this study can provide useful information for neurosurgeons, neurotologist and otolaryngologists involved in retrosigmoid approach for internal acoustic meatus tumor surgery and cerebellopontine angle surgery, and for patients undergoing cochlear implant planning with a retrofacial approach., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: Lateral semicircular canal (LSCC) malformations  are one of the most common inner ear malformations. The purpose of this study is to analyze the prevalence and type of hearing losses associated with LSCC malformations, compared to a control group., Materials and Methods: We retrospectively included 109 patients (166 ears) presenting with a CT-confirmed LSCC malformation, compared to a control group (24 patients). The bony island surface and the width of the inner portion of the LSCC were measured to confirm the malformation. There results were correlated to audiogram data: sensorineural (SHNL), mixed (MHL) or conductive hearing loss (CHL) by an otologist., Results: In the LSCC group, 60.9% of patients presented with an audiogram-confirmed hearing loss, especially SNHL (39.2%, n = 65) and MHL (12.7%, n = 21). Hearing was normal in 39.2% (n = 65) of the cases. Bilateral LSCC malformations (n = 57) were frequently associated with hearing loss (80.7%), SNHL in most of the cases (33.3%). Unilateral LSCC malformations were associated with hearing alterations (51.9%, n = 27), but we also observed a high rate (81%, n = 42) of contralateral abnormalities of the audiogram., Conclusion: LSCC malformations are commonly associated with hearing loss (61%), especially SHNL (39%). The high rate (81%) of contralateral hearing disturbances in unilateral LSCC malformations should be taken into account in the patient's daily life to avoid triggering or exacerbating any hearing loss. Otologists and radiologists must cooperate to ensure that all malformations are correctly described on CT, especially to improve the patient's education regarding hearing preservation.

To provide an overview of anomalies of the temporal bone in CHARGE syndrome relevant to cochlear implantation (CI), anatomical structures of the temporal bone and the respective genotypes were analysed. In this retrospective study, 42 CTs of the temporal bone of 42 patients with CHARGE syndrome were reviewed in consensus by two head-and-neck radiologists and two otological surgeons. Anatomical structures of the temporal bone were evaluated and correlated with genetic data. Abnormalities that might affect CI surgery were seen, such as a vascular structure, a petrosquamosal sinus (13 %), an underdeveloped mastoid (8 %) and an aberrant course of the facial nerve crossing the round window (9 %) and/or the promontory (18 %). The appearance of the inner ear varied widely: in 77 % of patients all semicircular canals were absent and the cochlea varied from normal to hypoplastic. A stenotic cochlear aperture was observed in 37 %. The middle ear was often affected with a stenotic round (14 %) or oval window (71 %). More anomalies were observed in patients with truncating mutations than with non-truncating mutations. Temporal bone findings in CHARGE syndrome vary widely. Vascular variants, aberrant route of the facial nerve, an underdeveloped mastoid, aplasia of the semicircular canals, and stenotic round window may complicate cochlear implantation., Competing Interests: All authors declare that they have no conflict of interest. Ethical approval All procedures performed in the studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent Informed consent was obtained from all individual participants included in the study.

Inner ear bone malformations are one cause of profound sensorineural hearing loss. This investigation focused on those affecting the posterior labyrinth, especially enlarged vestibular aqueduct syndrome, which is associated with fluctuating and progressive hearing loss. The objectives of this study were to analyze the behavior of the electrical stimulation, auditory functionality and linguistic development in patients with inner ear malformations involving the posterior labyrinth. The study included ten patients undergoing cochlear implantation (cases: five with enlarged vestibular aqueduct, two with vestibular aqueduct stenosis/aplasia, and three with semicircular canal disorders). Post-implantation, data were gathered on the electrical stimulation threshold and maximum comfort levels and on the number of functioning electrodes. Evaluation of Auditory Responses to Speech (EARS) subtests were used to assess auditory functionality and language acquisition at 6, 12, and 24 months post-implantation. Results were compared with findings in a control group of 28 cochlear implantation patients without these malformations. No significant differences were found between case and control groups in electrical stimulation parameters; auditory functionality subtest scores were lower in cases than controls, although the difference was only statistically significant for some subtests. In conclusion, cochlear implantation patients with posterior labyrinth bone malformations and profound hearing loss, including those with enlarged vestibular aqueduct syndrome, showed no significant difference in electrical stimulation threshold with controls. Although some auditory functionality test results were lower in cases than in controls, cochlear implantation appears to be beneficial for all patients with these malformations.

CHARGE syndrome is a rare, polymalformative disease, representing one of the major causes of associated blindness and deafness. Bilateral, severe-profound, sensorineural hearing loss is common in CHARGE children. Aim of this study is to present our results in children with "CHARGE syndrome" submitted to cochlear implantation (CI). The frequency of anatomic anomalies, possible variations in the surgical technique of CI, and the audiological/rehabilitative benefits attained in our patients are reported. we submitted 5 children affected by CHARGE syndrome with profound, bilateral, sensorineural hearing loss to CI. Otoacoustic emissions, auditory brainstem response, acoustic impedance testing, cranial computed tomography and magnetic resonance were carried out preoperatively in all children. CI was performed using the mastoidotomy-posterior tympanotomy approach in two cases, and the suprameatal approach in three children. Infant toddler-meaningful auditory integration scale was used to evaluate kid's audiological performance before and after CI. Intra-operatory findings and postsurgical complications were evaluated. Among our patients, intraoperative anatomical malformations were cochlear hypoplasia (100 %), ossicles malformations (100 %), semicircular canals aplasia (100 %), oval window atresia (60 %), round window atresia (40 %), widening of the aqueduct of the vestibule (20 %), and aberrant course of the facial nerve (20 %). No intra- or postoperative complication was recorded in relation to implant positioning. After a follow-up ranging from 1 to 4.5 years, only 2/5 patients used oral language as the sole mean of communication, 1 started utilizing oral language as the main mean of communication, while 2 patients did not develop any linguistic ability. In conclusion, CI in patients with CHARGE association is feasible and, despite results variability, it should be carried out in CHARGE children with severe hearing loss as soon as possible. Although the selection of a specific surgical technique does not seem to influence the audiological outcome, the suprameatal access is valuable when important surgical landmarks (i.e. lateral semicircular canal and incus) are absent.

Objective: To determine features of hypoplasia and aplasia of the vestibulocochlear nerve (VCN) in combination with inner ear malformations (IEMs)., Methods: Index cases were retrospectively selected from all IEMs collected since 1995. CT and MRI data were reviewed by two neuroradiologists. The number and thickness of visible nerves in the cerebellopontine angle cistern and inside the internal auditory canal (IAC) were analysed., Results: MR images for 176 patients with IEMs were analysed. Labyrinthine aplasia and otocyst deformity showed 100% correlation, and IAC malformations exhibited 92% correlation with VCN aplasia. Cochlear aplasia, complete aplasia of the semicircular canals, severe cochlear hypoplasia, common cavity, incomplete partition type 1 and mild cochlear hypoplasia showed decreasing degrees of correlation with hypoplasia of the VCN. The remaining types of IEM did not demonstrate VCN hypoplasia., Conclusions: Certain forms of IEM show 100% correlation with hypoplasia or aplasia of the VCN, while others correlate less strongly and some do not usually exhibit VCN hypoplasia. MRI should always be carried out for those forms often correlated with VCN hypoplasia., Key Points: Vestibulocochlear nerve deficiency can be strongly suspected in certain inner ear malformations • Bony cochlear aplasia and cochlear nerve aplasia are strongly correlated • In semicircular canal aplasia, hypoplasia of the vestibular nerve can be found • Before cochlear implantation, the type of any IEM should be fully understood.