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Multiphoton imaging for morphometry of the sandwich-beam structure of the human stapedial annular ligament
摘要： Background: The annular ligament of the human stapes constitutes a compliant connection between the stapes footplate and the peripheral cochlear wall at the oval window. The cross section of the human annular ligament is characterized by a three-layered structure, which resembles a sandwich-shaped composite structure. As accurate and precise descriptions of the middle-ear behavior are constrained by lack of information on the complex geometry of the annular ligament, this study aims to obtain comprehensive geometrical data of the annular ligament via multiphoton imaging. Methods: The region of interest containing the stapes and annular ligament was harvested from a fresh-frozen human temporal bone of a 46-years old female. Multiphoton imaging of the unstained sample was performed by detecting the second-harmonic generation of collagen and the autofluorescence of elastin, which are constituents of the annular ligament. The multiphoton scans were conducted on the middle-ear side and cochlear side of the annular ligament to obtain accurate images of the face layers on both sides. The face layers of the annular ligament were manually segmented on both multiphoton scans, and then registered to high-resolution mCT images. Results: Multiphoton scans of the annular ligament revealed 1) relatively large thickness of the core layer compared to the face layers, 2) asymmetric geometry of the face layers between the middle-ear side and cochlear side, and variation of their thickness and width along the footplate boundary, 3) divergent relative alignment of the two face layers, and 4) different fiber composition of the face layers along the boundary with a collagen-reinforcement near the anterior pole on the middle-ear side. Conclusion and outlook: Multiphoton microscopy is a feasible approach to obtain the detailed three-dimensional features of the human stapedial annular ligament along its full boundary. The detailed description of the sandwich-shaped structures of the annular ligament is expected to contribute to modeling of the human middle ear for precise simulation of middle-ear behavior. Further, established methodology in this study may be applicable to imaging of other middle-ear structures.
关键词： Stapes,Two-photon microscopy,Multiphoton microscopy,Core layer,Face layer,Annular ligament
更新于2025-09-23 15:23:52
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Mid-term evaluation of perioperative i.v. corticosteroid treatment efficacy on overall and audiological outcome following CO2 laser stapedotomy: a retrospective study of 84 cases
摘要： Purpose Our aim was to determine whether perioperatively administered corticosteroid treatment has any beneficial effect on the outcome of stapes surgery, with special regard to the audiological results and early postoperative morbidity. Methods 84 CO2 laser stapedotomies performed in our institute between 2013 and 2018 were included in our investigation. All cases underwent preoperative and mid-term postoperative pure-tone audiometric evaluation. Vestibular complications were also evaluated. The cases were subdivided into two groups, 23 patients received perioperative i.v. methylprednisolone treatment (“S”) while the other 61 patients (“nS”) did not receive any adjuvant pharmacological therapy. The data were analyzed retrospectively using IBM SPSS Statistics. Results CO2 laser stapedotomy proved to be a successful intervention with a significant improvement in ABG and AC thresholds as well. Long-term BC levels were significantly better compared to preoperative ones in the S group; however, in the nS group, no difference could be shown. Hearing and ABG gain were significantly superior in group S [28.1?dB (SD11.2) vs. 18.1?dB (SD 10.9) and 23.9?dB(SD 9.8) vs. 17.2?dB (SD 9.5), respectively]. Conclusion No significant inner ear damage was detectable in the results of our CO2 laser stapedotomy method; however, the positive effect of corticosteroid treatment could be demonstrated through the postoperative hearing levels. We found no statistical difference in early postoperative morbidity. According to our data, the routine administration of corticosteroids during stapes surgery could be an issue worthy of consideration. The effects of perioperative treatment vs that on the first day after surgery, and topical vs. systemic treatment could be the subject of further investigation in a prospective manner.
关键词： Middle ear,Stapes surgery,Otosclerosis,Stapedotomy,Corticosteroid therapy,Audiology,CO2 laser
更新于2025-09-19 17:13:59
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Risks of Intracochlear Pressures From Laser Stapedotomy
摘要： Hypothesis: Surgical manipulations during laser stapedotomy can produce intracochlear pressure changes comparable to pressures created by high-intensity acoustic stimuli. Background: New-onset sensorineural hearing loss is a known risk of stapes surgery and may result from pressure changes from laser use or other surgical manipulations. Here, we test the hypothesis that high sound pressure levels are generated in the cochlea during laser stapedotomy. Methods: Human cadaveric heads underwent mastoidectomy. Fiber-optic sensors were placed in scala tympani and vestibuli to measure intracochlear pressures during key steps in stapedotomy surgery, including cutting stapedius tendon, lasering of stapedial crurae, crural downfracture, and lasering of the footplate. Results: Key steps in laser stapedotomy produced high-intensity pressures in the cochlea. Pressure transients were comparable to intracochlear pressures measured in response to high intensity impulsive acoustic stimuli. Conclusion: Our results demonstrate that surgical manipulations during laser stapedotomy can create significant pressure changes within the cochlea, suggesting laser application should be minimized and alternatives to mechanical downfracture should be investigated. Results from this investigation suggest that intracochlear pressure transients from stapedotomy may be of sufficient magnitude to cause damage to the sensory epithelium and affirm the importance of limiting surgical traumatic exposures.
关键词： Stapedectomy,Noise induced hearing loss,Stapedotomy,Intracochlear pressure,Stapes prosthesis
更新于2025-09-12 10:27:22