New model of superior semicircular canal dehiscence with reversible diagnostic findings characteristic of patients with the disorder.

Autor:	Wackym PA; Department of Otolaryngology - Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, United States.; Rutgers Brain Health Institute, New Brunswick, NJ, United States., Balaban CD; Departments of Otolaryngology, Neurobiology, Communication Sciences and Disorders, Bioengineering and Mechanical Engineering and Materials Science, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States., Van Osch OJ; Department of Otolaryngology - Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, United States., Morris BT; Department of Otolaryngology - Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, United States., Tamakloe MA; Department of Otolaryngology - Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, United States., Salvatore VL; Department of Otolaryngology - Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, United States., Duwadi S; Department of Otolaryngology - Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, United States., Gay JD; Department of Otolaryngology - Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, United States., Mowery TM; Department of Otolaryngology - Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, United States.; Rutgers Brain Health Institute, New Brunswick, NJ, United States.
Jazyk:	angličtina
Zdroj:	Frontiers in neurology [Front Neurol] 2023 Jan 19; Vol. 13, pp. 1035478. Date of Electronic Publication: 2023 Jan 19 (Print Publication: 2022).
DOI:	10.3389/fneur.2022.1035478
Abstrakt:	Background: Third window syndrome is a vestibular-cochlear disorder in humans in which a third mobile window of the otic capsule creates changes to the flow of sound pressure energy through the perilymph/endolymph. The nature and location of this third mobile window can occur at many different sites (or multiple sites); however, the most common third mobile window is superior semicircular canal dehiscence (SSCD). There are two essential objective diagnostic characteristics needed to validate a model of SSCD: the creation of a pseudoconductive hearing loss and cVEMP increased amplitude and decreased threshold. Methods: Adult Mongolian gerbils ( n = 36) received surgical fenestration of the superior semicircular canal of the left inner ear. ABR and c+VEMP testing were carried out prior to surgery and over acute (small 1 mm SSCD, 1-10 days) or prolonged (large 2 mm SSCD, 28 days) recovery. Because recovery of function occurred quickly, condenser brightfield stereomicroscopic examination of the dehiscence site was carried out for the small SSCD animals post-hoc and compared to both ABRs and c+VEMPs. Micro-CT analysis was also completed with representative samples of control, day 3 and 10 post-SSCD animals. Results: The SSCD created a significant worsening of hearing thresholds of the left ear; especially in the lower frequency domain (1-4 kHz). Left (EXP)/right (CTL) ear comparisons via ABR show significant worsening thresholds at the same frequency representations, which is a proxy for the human pseudoconductive hearing loss seen in SSCD. For the c+VEMP measurements, increased amplitude of the sound-induced response (N1 2.5 ms and P1 3.2 ms) was observed in animals that received larger fenestrations. As the bone regrew, the c+VEMP and ABR responses returned toward preoperative values. For small SSCD animals, micro-CT data show that progressive osteoneogenesis results in resurfacing of the SSCD without bony obliteration. Conclusion: The large (2 mm) SSCD used in our gerbil model results in similar electrophysiologic findings observed in patients with SSCD. The changes observed also reverse and return to baseline as the SSCD heals by bone resurfacing (with the lumen intact). Hence, this model does not require a second surgical procedure to plug the SSCD. Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. (Copyright © 2023 Wackym, Balaban, Van Osch, Morris, Tamakloe, Salvatore, Duwadi, Gay and Mowery.)
Databáze:	MEDLINE
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