Anatomical and morphometric study of goat middle ear ossicles (Capra aegagrus hircus)

ABSTRACT The social and economic roles of goat farming in Northeastern Brazil, allied to the fact that the use of goat middle ear ossicles for research and human ear surgery training has not yet been proposed, justify the study of their applicability as an experimental model. The middle ears of 19 goats (Capra aegagrus hircus) from the bone collection of the Laboratory and Didactic Anatomy Museum of Domestic and Wild Animals of the Federal University of Vale do São Francisco (UNIVASF) were dissected. The malleus, incus, and stapes were evaluated regarding their macroscopic morphology and biometry (length, width, and height). Ossicle morphology was similar to sheep, human, and bovine morphology. The malleus was 1.3 times heavier and 2.2 times longer than the incus, and 9.0 times heavier and 3.7 times longer than the stapes. The size relationship was positive between the stapes and the malleus and negative between the stapes and the incus. It is concluded that the middle ear size and the anatomical similarities with human ossicles make goats a useful model for experimental scientific studies, reconstructive surgery practice of the ossicular chain, and human ear surgery training.

Are Hounsfield Unit Measurements of Bony Absorption Changes in Cholesteatoma Helpful?

Introduction High-resolution computed tomography (HRCT) scans of the temporal bone are used to assess the bony erosion of the middle-ear structures whenever cholesteatoma is suspected. Objective To study the differences in HRCT Hounsfield unit (HU) index measurements of middle-ear bony structures between an ears with and without cholesteatoma. Methods A retrospective study of 59 patients who underwent surgery due to unilateral cholesteatoma. The HRCT HU index of the scutum, of three middle-ear ossicles, of the lateral semicircular canal (LSCC), and of the fallopian canal was measured in both ears. A comparison was made between the cholesteatoma and the non-cholesteatomatous ear (control). All measurements were conducted by an otolaryngologist. To assess the interobserver bias, 10% of the samples were randomly and independently assessed by another otolaryngologist and a neuroradiologist who were blinded. Results The average HU index was lower in the ear with cholesteatoma when compared with the non-cholesteatomatous ear. While the differences were statistically significant regarding the measurements of the scutum (516.02 ± 311.693 versus 855.64 ± 389.999; p = 0.001), the malleus (1049.44 ± 481.765 versus 1413.47 ± 313.376; p = 0.01), and the incus (498.03 ± 264.184 versus 714.25 ± 405.631; p = 0.001), the differences in the measurements of the LSCC (1042.34 ± 301.066 versus 1154.53 ± 359.609; p = 0.69) and of the fallopian canal (467.19 ± 221.556 versus 543.51 ± 263.573; p = 0.108) were not significantly different between both groups. The stapes was immeasurable in both groups due to its small size. Conclusion Hounsfield unit index measurements are a useful tool that may aid in the diagnosis of early-stage cholesteatoma.

Hearing loss in Morquio disease: a scoping review protocol (Preprint)

UNSTRUCTURED Objective: This scoping review aimed to understand the extent and type of evidence in relation to physiopathology, classification, epidemiology, clinical management, and effect of therapy for hearing loss in patients with mucopolysaccharidosis (MPS) IVA. Introduction: Mild to moderate hearing loss is common in patients with MPS IVA. The hearing loss can be conductive, sensorineural, or mixed. However, in these patients, the mixed form is frequent, attributed to the combination of conductive and neurosensory elements, with a slowly progressive evolution. Conductive hearing loss may be secondary to recurrent upper respiratory tract infections, serous otitis media, and deformity of the ear ossicles due to accumulation of glycosaminoglycans (GAGs). Meanwhile, the sensorineural form is mainly attributed to the accumulation of GAG in the auditory system.. Inclusion criteria: This scoping review include participants of both sexes, without specific age, who are diagnosed with mucopolysaccharidosis IVA and who develop hearing loss as a comorbidity. None exclusion criteria (country, language or document type) will be applicable. Methods: This scoping review includes participants of both sexes, without specific age, who are diagnosed with MPS IVA and develop hearing loss as comorbidity. No exclusion criteria (country, language, or document type) will be applicable. The information sources will include experimental and quasi-experimental, analytical observational, observational, and qualitative studies. Unpublished literature will not be covered. Gray literature will not be covered. Two independent reviewers will participate in the process of screening the literature, paper selection, and data extraction, and this process will be performed blindly. When all manuscripts have been selected by two reviewers, disagreements that arise between the reviewers at each stage of the selection process will be resolved through discussion or with an additional reviewer. Results will be reported with descriptive statistics and diagrammatic or tabular displayed information as explained in the JBI guidelines.

How Is the Cochlea Activated in Response to Soft Tissue Auditory Stimulation in the Occluded Ear?

Soft tissue conduction is an additional mode of auditory stimulation which can be initiated either by applying an external vibrator to skin sites not overlying skull bone such as the neck (so it is not bone conduction) or by intrinsic body vibrations resulting, for example, from the heartbeat and vocalization. The soft tissue vibrations thereby induced are conducted by the soft tissues to all parts of the body, including the walls of the external auditory canal. In order for soft tissue conduction to elicit hearing, the soft tissue vibrations which are induced must penetrate into the cochlea in order to excite the inner ear hair cells and auditory nerve fibers. This final stage can be achieved either by an osseous bone conduction mechanism, or, more likely, by the occlusion effect: the vibrations of the walls of the occluded canal induce air pressures in the canal which drive the tympanic membrane and middle ear ossicles and activate the inner ear, acting by means of a more air conduction-like mechanism. In fact, when the clinician applies his stethoscope to the body surface of his patient in order to detect heart sounds or pulmonary air flow, he is detecting soft tissue vibrations.

Radio-surgical correlation of chronic suppurative otitis media

<p class="abstract"><strong>Background:</strong> Chronic suppurative otitis media (CSOM) because of disease nature and location of vital structures like middle ear ossicles, facial nerve, and lateral semicircular canal poses clinical as well as radiological challenge in diagnosis, especially the squamosal variety. Hence this study to evaluate radio-surgical correlation in cases of CSOM.</p><p class="abstract"><strong>Methods:</strong> We retrospectively analysed 92 case records who met the inclusion criteria. Their pre-operative high-resolution computed tomography (HRCT) temporal bone imaging was evaluated for erosion of the ossicular chain and the fallopian canal. This was correlated with the surgical findings noted intra-operatively. The appropriate statistical analysis was carried out. The radio-surgical correlation was evaluated by Cohen’s kappa value. </p><p class="abstract"><strong>Results:</strong> The kappa value for status of ossicular chain was 0.805 and 0.384 for status of fallopian canal. HRCT imaging had a positive predictive value and negative predictive value of 94.3% and 85.3% respectively, in detecting ossicular chain erosion. In detecting fallopian canal erosion, HRCT showed a sensitivity of 33.3%. Analysing the individual ossicles, we found kappa to be 0.266 for malleus, 0.463 for incus and 0.827 for stapes.</p><p class="abstract"><strong>Conclusions:</strong> There was excellent radio-surgical correlation for ossicular chain erosion while it was poor for fallopian canal erosion. HRCT showed excellent radio-surgical correlation for stapes, moderate for incus and poor for malleus. In-spite of its shortcomings in differentiating cholesteatoma and non-cholesteatomatous pathologies of the middle ear cleft, HRCT imaging plays a key role in assessing the status of the ossicles and fallopian canal.</p><p> </p>