OBJECTIVE: This study aims to discern the disparities in the electrode-to-modiolus distance (EMD) between cochleostomy and round window approaches when performed sequentially in the same temporal bone. Additionally, the study seeks to identify the cochlear metrics that contribute to these differences.
METHODS: A cross-sectional study was conducted, involving the sequential insertion of a 12-electrode array through both round window and cochleostomy approaches in cadaveric temporal bones. Postimplantation high-resolution CT scans were employed to calculate various parameters.
RESULTS: A total of 12 temporal bones were included in the imaging analysis, revealing a mean cochlear duct length of 32.892 mm. The EMD demonstrated a gradual increase from electrode 1 (C1) in the apex (1.9 ± 0.07 mm; n = 24) to electrode 12 (C12) in the basal turn (4.6 ± 0.24 mm; n = 12; p < 0.01). Significantly higher EMD values were observed in the cochleostomy group. Correlation analysis indicated a strong positive correlation between EMD and cochlear perimeter (CP) (rs = 0.64; n = 12; p = 0.03) and a strong negative correlation with the depth of insertion (DOI) in both the middle and basal turns (rs = - 0.78; n = 20; p < 0.01). Additionally, EMD showed a strong negative correlation with the DOI-CP ratio (rs = -0.81; n = 12; p < 0.01).
CONCLUSIONS: The cochleostomy group exhibited a significantly higher EMD compared with the round window group. The strong negative correlation between EMD and DOI-CP ratio suggests that in larger cochleae with shallower insertions, EMD is greater than in smaller cochleae with deeper insertions.
METHODS: N/A Laryngoscope, 2024.

Relapsing polychondritis is an autoimmune disorder causing inflammation of cartilaginous structures, sensory epithelium, and cardiovascular system. Hearing loss is a rare and dreadful complication of this pathology. We report a case of relapsing polychondritis in a 38-year-old female who developed gradually progressive bilateral profound hearing loss. She did not have any improvement with medical management. Cochlear implantation was performed to rehabilitate her hearing. As the scala tympani was obliterated, a scala vestibuli insertion was performed. A complete insertion was possible with a compressed electrode, and she had good evoked compound action potential scores. Her categories of auditory performance scores were 6 at the end of one year. Patients with relapsing polychondritis can progress to profound hearing loss in rare cases and should be carefully followed up to identify early labyrinthine ossification. A scala vestibuli insertion can be performed with good outcomes in cases with ossification involving scala tympani. The surgeon should be ready for a middle-turn cochleostomy or a drill-out procedure in patients with advanced ossification.

UNASSIGNED: For experimental studies on sound transfer in the middle ear, it may be advantageous to perform the measurements without the inner ear. In this case, it is important to know the influence of inner ear impedance on the middle ear transfer function (METF). Previous studies provide contradictory results in this regard. With the current study, we investigate the influence of inner ear impedance in more detail and find possible reasons for deviations in the previous studies.
UNASSIGNED: 11 fresh frozen temporal bones were prepared in our study. The factors related to inner ear impedance, including round window membrane stiffness, cochleostomy, cochlea fluid and cochlea destruction were involved in the experimental design. After measuring in the intact specimen as a reference (step 1), the round window membrane was punctured (step 2), then completely removed (step 3). The cochleostomy was performed (step 4) before the cochlear fluid was carefully suctioned through scala tympani (step 5) and scala vestibuli (step 6). Finally, cochlea was destroyed by drilling (step 7). Translational and rotational movement of the stapes footplate were measured and calculated at each step. The results of the steps were compared to quantify the effect of inner ear impedance changing related to the process of cochlear drainage.
UNASSIGNED: As the inner ear impedance decreases from step 1 to 7, the amplitudes of the METF curves at each frequency gradually increase in general. From step 6 on, the measured METF are significantly different with respect to the intact group at high frequencies above 3 kHz. The differences are frequency dependent. However, the significant decrement of rotational motion appears at the frequencies above 4.5 kHz from the step 5.
UNASSIGNED: This study confirms the influence of inner ear impedance on METF only at higher frequencies (≥3 kHz). The rotational motions are more sensitive to the drainage of fluid at the higher frequency. Study results that found no influence of cochlea impedance may be due to incomplete drainage of the cochlea.

BACKGROUND: Round window approach and cochleostomy approach can have different depth of electrode insertion during cochlear implantation which itself can alter the audiological outcomes in cochlear implant.
OBJECTIVE: The current study was conducted to determine the difference in the depth of electrode insertion via cochleostomy and round widow approach when done serially in same temporal bone.
METHODS: This is a cross-sectional study conducted in the Department of Otorhinolaryngology in conjunction with Department of Anatomy and Department of Diagnostic and Interventional Radiology over a period of 1 year. 12-electrode array insertion was performed via either approach (cochleostomy or round window) in the cadaveric temporal bone. HRCT temporal bone scan of the implanted temporal bone was done and depth of insertion and various cochlear parameters were calculated.
RESULTS: A total of 12 temporal bones were included for imaging analysis. The mean cochlear duct length was 32.892 mm; the alpha and beta angles were 58.175° and 8.350°, respectively. The mean angular depth of electrode insertion via round window was found to be 325.2° (SD = 150.5842) and via cochleostomy 327.350 (SD = 112.79) degree and the mean linear depth of electrode insertion via round window was found to be 18.80 (SD = 4.4962) mm via cochleostomy 19.650 (SD = 3.8087) mm, which was calculated using OTOPLAN 1.5.0 software. There was a statically significant difference in linear depth of insertion between round window and cochleostomy. Although the angular depth of insertion was higher in CS group, there was no statistically significant difference with round window type of insertion.
CONCLUSIONS: The depth of electrode insertion is one of the parameters that influences the hearing outcome. Linear depth of electrode insertion was found to be more in case of cochleostomy compared to round window approach (p = 0.075) and difference in case of angular depth of electrode insertion existed but not significant (p = 0.529).

The present video reports the surgical removal of an intralabyrinthine schwannoma. The video contains patient\'s medical history, preoperative radiological evaluations and detailed description of surgical steps of the procedure, consisting in labyrinthectomy, cochleostomy and insertion of a dummy electrode in the preserved cochlear lumen within the context of a subtotal petrosectomy.

Background: The persistent stapedial artery (PSA) is a rare congenital vascular malformation involving the middle ear. It is usually associated with pulsatile tinnitus and/or conductive hearing loss and can account for multiple risks during middle ear surgery. Case Report: we present a case of a 9-year-old male child with conductive hearing loss and persistent stapedial artery in his right ear, who was admitted to our ENT Department for hearing loss. During surgery, we discovered PSA along with congenital stapes agenesis and oval window atresia, as well as an abnormal trajectory of the mastoid segment of the facial nerve. After ossicular reconstruction (transcanal total ossicular replacement prosthesis) with cochleostomy, no surgical complications were recorded and hearing improvement was monitored by pre- and postoperative audiometry. Conclusion: Stapedial artery is a rare anatomical middle ear abnormality that can prevent proper surgical hearing restoration and can be associated with other simultaneous temporal bone malformations.

UNASSIGNED: Electrocochleography (ECochG) is increasingly used in cochlear implant (CI) surgery, in order to monitor the effect of insertion of the electrode array aiming to preserve residual hearing. However, obtained results are often difficult to interpret. Here we aim to relate changes in ECochG responses to acute trauma induced by different stages of cochlear implantation by performing ECochG at multiple time points during the procedure in normal-hearing guinea pigs.
UNASSIGNED: Eleven normal-hearing guinea pigs received a gold-ball electrode that was fixed in the round-window niche. ECochG recordings were performed during the four steps of cochlear implantation using the gold-ball electrode: (1) Bullostomy to expose the round window, (2) hand-drilling of 0.5-0.6 mm cochleostomy in the basal turn near the round window, (3) insertion of a short flexible electrode array, and (4) withdrawal of electrode array. Acoustical stimuli were tones varying in frequency (0.25-16 kHz) and sound level. The ECochG signal was primarily analyzed in terms of threshold, amplitude, and latency of the compound action potential (CAP). Midmodiolar sections of the implanted cochleas were analyzed in terms of trauma to hair cells, modiolar wall, osseous spiral lamina (OSL) and lateral wall.
UNASSIGNED: Animals were assigned to cochlear trauma categories: minimal (n = 3), moderate (n = 5), or severe (n = 3). After cochleostomy and array insertion, CAP threshold shifts increased with trauma severity. At each stage a threshold shift at high frequencies (4-16 kHz) was accompanied with a threshold shift at low frequencies (0.25-2 kHz) that was 10-20 dB smaller. Withdrawal of the array led to a further worsening of responses, which probably indicates that insertion and removal trauma affected the responses rather than the mere presence of the array. In two instances, CAP threshold shifts were considerably larger than threshold shifts of cochlear microphonics, which could be explained by neural damage due to OSL fracture. A change in amplitudes at high sound levels was strongly correlated with threshold shifts, which is relevant for clinical ECochG performed at one sound level.
UNASSIGNED: Basal trauma caused by cochleostomy and/or array insertion should be minimized in order to preserve the low-frequency residual hearing of CI recipients.

UNASSIGNED: To characterize normative adult ranges for cochlear promontory thickness relevant to the development of subendosteal and transpromontory electrodes to rehabilitate various neurotologic disorders.
UNASSIGNED: Adults (≥18 years).
UNASSIGNED: In vivo radiologic assessment using a 192-slice CT scanner (Force-192; Siemens Healthcare) with ultrahigh-resolution scan mode combined and iterative reconstruction.
UNASSIGNED: Cochlear promontory thickness.
UNASSIGNED: Among 48 included patients (96 ears), the mean (SD) age was 56 (18) years (range 25-94) and included 25 (52%) women. Of that 12 patients (25%) had osteopenia (n = 6) or osteoporosis (n = 6). The mean (SD) body mass index was 28 (5) kg/m2. The mean (SD) promontory thickness for the 96 temporal bones under study was 1.22 (0.24) mm (range 0.55-1.85). There was not a statistically significant association between age and promontory thickness (correlation coefficient .08; p = .44). Promontory thickness was significantly greater for men than women (mean 1.28 vs. 1.17 mm; p = .03) and increased with increasing body mass index (correlation coefficient .30; p = .004). Last, promontory thickness was significantly less for patients with osteopenia or osteoporosis compared with those without these conditions (mean 1.09 vs. 1.27 mm; p = .002).
UNASSIGNED: Cochlear promontory thickness can vary by almost 1.5 mm across patients and is significantly associated with patient sex, body mass index, and comorbid osteopenia/osteoporosis. Subendosteal and transpromontory electrode placement techniques must account for this degree of variability.
UNASSIGNED: IV.

To study the postoperative visualisation of the electrode array insertion angle through transcanal Veria approach in both round window and cochleostomy techniques. Retrospective study. Tertiary care centre. 26 subjects aged 2-15 years implanted with a MED-EL STANDARD electrode array (31.5 mm) through Veria technique were selected. 16 had the electrode insertion through the round window, 10 through anteroinferior cochleostomy. DICOM files of postoperative computer tomography (CT) scans were collected and analysed using the OTOPLAN 3.0 software. Examined parameters were cochlear duct length, average angle of insertion depth. Pearson\'s Correlation Test was utilized for statistical analysis. Average cochlear duct length was 38.12 mm, ranging from 34.2 to 43 mm. Average angle of insertion depth was 666 degrees through round window insertion and 670 degrees through cochleostomy insertion. Pearson\'s correlation showed no significant difference in average angle of insertion depth between subjects with cochleostomy and round window insertion. Detailed study on the OTOPLAN software has established that there remains no difference between round window insertion or cochleostomy insertion when it comes to electrode array position and placement in the scala tympani. It is feasible to perform round window insertion and cochleostomy insertion through transcanal Veria approach as this technique provides good visualisation.
UNASSIGNED: The online version contains supplementary material available at 10.1007/s12070-022-03228-5.

Cochlear implant electrode array misplacement is a rare but serious complication that may result in failure of hearing rehabilitation, non-auditory percepts, vestibular disturbance, or damage to adjacent neurovascular structures. We present a case of an elderly patient who suffered electrode array misplacement into the posterior semicircular canal, resulting in vestibular symptoms and severe downstream sequelae. The risk of misplacement may be higher in patients with a history of chronic otitis media or prior otologic surgery, and with the use of pre-curved electrode arrays. Electrophysiological testing and intraoperative imaging may allow for early detection and intervention in these cases. Laryngoscope, 133:175-177, 2023.