The auditory ossicles amplify and transmit sound from the environment to the inner ear. The distribution of bone mineral density is crucial for the proper functioning of sound transmission as the ossicles are suspended in an air-filled chamber. However, little is known about the distribution of bone mineral density along the human ossicular chain and within individual ossicles. To investigate this, we analyzed fresh-frozen human specimens using synchrotron-based phase-contrast microtomography. In addition, we analyzed the volume and porosity of the ossicles. The porosity for the auditory ossicles lies, on average, between 1.92% and 9.85%. The average volume for the mallei is 13.85 ± 2.15 mm3, for the incudes 17.62 ± 4.05 mm3 and 1.24 ± 0.29 mm3 for the stapedes. The bone density distribution showed a similar pattern through all samples. In particular, we found high bone mineralization spots on the anterior crus of the stapes, its footplate, and along areas that are crucial for the transmission of sound. We could also see a correlation between low bone mineral density and holey areas where the bone is only very thin or missing. Our study identified a similar pattern of bone density distribution within all samples: regions exposed to lower forces generally show higher bone density. Further, we observed that the stapes shows high bone mineral density along the anterior crus and its footplate, which may indicate its importance in transmitting sound waves to the inner ear.

OBJECTIVE: To describe the new semisynthetic total ossicular replacement prosthesis (New-SSTORP) and to evaluate the New-SSTORP ossiculoplasty results both with the presence and absence of the stapes superstructure.
METHODS: Prospective study.
METHODS: Tertiary referral center.
METHODS: From April 2023 to May 2023, 18 New-SSTORP ossiculoplasties were performed by the first author. In all patients, the New-SSTORP was interposed between the footplate and the eardrum. The study group was divided into two groups (group A and group B). Group A included 13 patients with the absence of stapes superstructure. Group B included five patients with the presence of stapes superstructure. A successful reconstruction was defined as a postoperative air-bone gap ABG ≤20 dB. For all patients of groups A and B, the last audiometric control considered was performed in January 2024. The mean follow-up was 8½ months. The χ2 test was used to compare results. p < 0.05 was considered significant.
METHODS: Mean postoperative ABG ≤20 dB.
RESULTS: At the end of follow-up, the overall success rate (ABG ≤20 dB) of New-SSTORP ossiculoplasty was obtained in 88.8% (n = 16 of 18) of cases. In group A, the success rate of New-SSTORP ossiculoplasty occurred in 84.6% (n = 11 of 13) of cases, and in group B, the success rate of New-SSTORP ossiculoplasty occurred in 100% (n = 5 of 5) of cases. There was no audiological statistically significant difference between groups A and B (Fisher value is 1; p < 0.05). In all cases, the time for positioning of New-SSTORP was about 5 minutes.
CONCLUSIONS: The New-SSTORP has a minimal technical challenge for building and placement. The New-SSTORP ossiculoplasty results are very good both with the presence and absence of SS.

Sound transmission to the human inner ear by bone conduction pathway with an implant attached to the otic capsule is a specific case where the cochlear response depends on the direction of the stimulating force. A finite element model of the temporal bone with the inner ear, no middle and outer ear structures, and an immobilized stapes footplate was used to assess the directional sensitivity of the cochlea. A concentrated mass represented the bone conduction implant. The harmonic analysis included seventeen frequencies within the hearing range and a full range of excitation directions. Two assessment criteria included: (1) bone vibrations of the round window edge in the direction perpendicular to its surface and (2) the fluid volume displacement of the round window membrane. The direction of maximum bone vibration at the round window edge was perpendicular to the round window. The maximum fluid volume displacement direction was nearly perpendicular to the modiolus axis, almost tangent to the stapes footplate, and inclined slightly to the round window. The direction perpendicular to the stapes footplate resulted in small cochlear responses for both criteria. A key factor responsible for directional sensitivity was the small distance of the excitation point from the cochlea.

OBJECTIVE: Revision stapes surgery is a challenging procedure performed in relatively small numbers compared to other middle ear procedures. Despite numerous data on hearing results of different middle ear surgeries, the audiological standards for successful outcome of this procedure are still not clarified. On the basis of well-documented data, we wanted to determine what the expected audiological results and complications are after revision stapes surgery in order to set a realistic threshold for surgical success.
METHODS: After the protocol registration in the PROSPERO database, a systematic review was performed in multiple databases (PubMed, Cochrane, Web of Science, Scopus, ScienceOpen, ClinicalTrials.gov, Google Scholar) according to PRISMA guidelines. Twelve articles were reviewed according to the inclusion criteria. A total of 1032 cases were obtained for evaluation. A modified version of Newcastle-Ottawa Scale (NOS) was used to assess publication quality.
RESULTS: Average air-bone gap (ABG) gain was 17.3 dB, average air conduction (AC) gain was 17.5 dB. The average postoperative air-bone gap was 11.1 dB. The postoperative ABG distribution was the following 0-10 dB: 53.3%, > 10-20 dB: 28.2%, > 20 dB: 18.5%. SNHL as a surgical complication was described in a total of 17 cases (1.6%), no equilibrium disorder was reported.
CONCLUSIONS: The pooled data suggest that revision stapes surgery is an effective solution after failure of previous stapes surgery. However, the results are clearly inferior to those of primary stapedotomies. Hence, we need to apply different expectations and use different standards in the indication and evaluation of this type of surgery.

The current work investigated the effects of mass-loading the eardrum on wideband absorbance in humans. A non-invasive approach to mass-loading the eardrum was utilized in which water was placed on the eardrum via ear canal access. The mass-loaded absorbance was compared to absorbance measured for two alternative middle ear states: normal and stiffened. To stiffen the ear, subjects pressurized the middle ear through either exsufflation or insufflation concurrent with Eustachian tube opening. Mass-loading the eardrum was hypothesized to reduce high-frequency absorbance, whereas pressurizing the middle ear was hypothesized to reduce low- to mid-frequency absorbance. Discriminant linear analysis classification was performed to evaluate the utility of absorbance in differentiating between conditions. Water on the eardrum reduced absorbance over the 0.7- to 6-kHz frequency range and increased absorbance at frequencies below approximately 0.5 kHz; these changes approximated the pattern of changes reported in both hearing thresholds and stapes motion upon mass-loading the eardrum. Pressurizing the middle ear reduced the absorbance over the 0.125- to 4-kHz frequency range. Several classification models based on the absorbance in two- or three-frequency bands had accuracy exceeding 88%.

The cause of sudden conductive loss in the absences of other vestibulo-audiologic abnormalities can be isolated to specific subsites of the ossicular chain using audiometric testing. In the absence of such abnormalities, a rare etiology may be the cause after an inciting trauma. Laryngoscope, 2024.

OBJECTIVE: To examine the clinical features and surgical outcomes in patients with congenital absence of the oval window (CAOW), and to investigate the potential factors that affect audiologic results.
METHODS: A retrospective chart review.
METHODS: A tertiary academic center.
METHODS: A total of 17 ears among 16 patients were confirmed to have CAOW. Among them, 13 ears underwent vestibulotomy for hearing reconstruction. Clinical parameters associated with the hearing outcomes were analyzed.
METHODS: A mean air-bone gap (ABG) after 6-month and long-term follow-up was compared with preoperative measurements.
RESULTS: Intraoperative findings showed that anomalies of the malleus or incus were observed in 11 ears (64.7%), stapes anomalies were present in all ears (100%), and facial nerve anomalies were present in 10 ears (58.8%). Because of unfavorable facial nerve anomalies, hearing reconstruction was aborted in four cases (23.5%). In the hearing reconstruction group, the mean ABG at 6 months postoperation was significantly reduced after compared with the preoperative value (44.0 ± 8.4 dB versus 58.8 ± 9.1 dB, p = 0.006). After dividing ears into a success subgroup (ABG ≤ 30 dB, seven ears) and non-success subgroup (ABG > 30 dB, six ears), the use of a drill during vestibulotomy was significantly related to a poor hearing outcome (100% versus 16.7%, p = 0.015). The long-term follow-up result (mean, 60 mo) revealed no deterioration compared with the 6-month postoperative result. Five ears (29.4%) underwent revision surgery, and three of them showed ABG improvements. No serious complications were reported.
CONCLUSIONS: Vestibulotomy is an effective and safe option for hearing restoration in patients with CAOW, particularly when the use of a drill is not required. The long-term audiologic outcome is also reliable.

UNASSIGNED: Stapes footplate thickness measurement using ultra-high-resolution CT has been described only in the lateral semicircular canal plane. The purpose of this study was to compare stapes footplate thickness between the lateral semicircular canal and stapes axial planes in patients with otosclerosis compared to controls.
UNASSIGNED: We performed a retrospective single-center study of patients undergoing high-resolution temporal bone CT. Two radiologists measured stapes footplate thickness in both the lateral semicircular canal and stapes axial planes.
UNASSIGNED: Between February 2020 and October 2022, we collected 81 ears from 49 patients (75% of women; mean age 51.22 ± 16.6 years, 17 otosclerosis, and 64 controls). In the stapes axial plane, there was a significant anterior thickening in otosclerosis patients (Reader 1: 0.52 ± 0.12 [0.3-0.7] vs. 0.41 ± 0.08 [0.3-0.6], p = 0.001; Reader 2: 0.54 ± 0.06 [0.5-0.7] vs. 0.39 ± 0.08 [0.2-0.6], P < 0.001) compared to controls. These differences were not significant using the lateral semicircular canal plane.
UNASSIGNED: The stapes footplate was thickened at its AC in otosclerosis patients using only the stapes axial plane.
UNASSIGNED: We propose to use the stapes axial plane instead of the lateral semicircular canal plane when analyzing the stapes.

OBJECTIVE: To describe the reliability of ultra-high-resolution computed tomography (UHR-CT) in the measurement of titanium stapes prostheses using manufacturer data as a reference.
METHODS: This retrospective study included patients treated by stapedectomy with titanium prostheses who underwent UHR-CT between January 2020 and October 2023. Images were acquired using an ultra-high-resolution mode (slice thickness: 0.25 mm; matrix, 1024 × 1024). Two radiologists independently evaluated the length, diameter, and intra-vestibular protrusion of the prosthesis. Post-operative air-bone gaps (ABGs) were recorded.
RESULTS: Fourteen patients were enrolled (mean age, 44.3 ± 13.8 [SD] years, 9 females), resulting in 16 temporal bone UHR-CTs. The exact length was obtained in 81.3 % (n = 13/16) and underestimated by 0.1 to 0.3 mm in the remaining 18.7 % (n = 3/16) CT scans for both readers (mean misestimation: -0.02 ± 0.06 [SD] mm, overall underestimation of 0.43 %). The exact diameter was reported in 75 % (n = 12/16) and 87.5 % (n = 14/16) of the CT scans for readers 1 and 2, respectively, and was off by 0.1 mm in all discrepancies (mean misestimation: 0.01 ± 0.04 [SD] mm, overall overestimation of 2.43 %). Intravestibular prosthesis protrusion was of 0.5 ± 0.43 [SD] mm (range: 0-1) and 0.49 ± 0.44 [SD] mm (range: 0-1.1) for readers 1 and 2, respectively, and did not correlate with ABGs (r = 0.25 and 0.22; P = 0.39 and 0.47 for readers 1 and 2, respectively). Intra and interobserver agreements were excellent.
CONCLUSIONS: UHR-CT provides 99.6 % and 97.6 % accuracy for prosthesis length and diameter measurements, respectively.

Elephants have a unique auditory system that is larger than any other terrestrial mammal. To quantify the impact of larger middle ear (ME) structures, we measured 3D ossicular motion and ME sound transmission in cadaveric temporal bones from both African and Asian elephants in response to air-conducted (AC) tonal pressure stimuli presented in the ear canal (PEC). Results were compared to similar measurements in humans. Velocities of the umbo (VU) and stapes (VST) were measured using a 3D laser Doppler vibrometer in the 7-13,000 Hz frequency range, stapes velocity serving as a measure of energy entering the cochlea-a proxy for hearing sensitivity. Below the elephant ME resonance frequency of about 300 Hz, the magnitude of VU/PEC was an order of magnitude greater than in human, and the magnitude of VST/PEC was 5x greater. Phase of VST/PEC above ME resonance indicated that the group delay in elephant was approximately double that of human, which may be related to the unexpectedly high magnitudes at high frequencies. A boost in sound transmission across the incus long process and stapes near 9 kHz was also observed. We discuss factors that contribute to differences in sound transmission between these two large mammals.