Abstract An experimental test section with horizontal and vertical heated plates forming an inverted L-shape is filled with 3 M Novec 7000 dielectric fluid at atmospheric pressure. Both plates of 64 ...× 40 mm 2 dimensions are heated with wall heat fluxes ranging from 0 to 20 W cm −2 . There is natural convection for low heat fluxes, medium heat fluxes trigger boiling and for higher power, the critical heat flux is reached. The wall temperature and heat flux are calculated from in-wall thermocouple measurements in steady state. The bubbly flow on the vertical surface is observed with a high-speed camera through a window. The confinement between the vertical heated surface and the wall is varied from 0.5 to 15 mm . In the range of this study, the heat transfer coefficient in natural convection and nucleate boiling regimes increases when the spacing decreases. However, since the critical heat flux decreases when it is more confined, the film boiling regime is reached faster. From the visualizations and the thermal measurements we try to model these different behaviors. Depending on which plate is switched on or off we observed different behaviors. The confinement of the vertical plate does not have any influence on the horizontal one since the plate width is much bigger than the gap change. Also, the horizontal plate heating does not influence the heat transfer on the vertical plate in this study. However, there is an influence of the vertical boiling on the horizontal one, stronger when there is a confinement than in free configuration.
Professional musicians (PMs) are at high risk of developing hearing loss (HL) and other audiological symptoms such as tinnitus, hyperacusis, and diplacusis. The aim of this systematic review is to ...(A) assess the risk of developing HL and audiological symptoms in PMs and (B) evaluate if different music genres (Pop/Rock Music-PR; Classical Music-CL) expose PMs to different levels of risk of developing such conditions. Forty-one articles including 4618 PMs were included in the study. HL was found in 38.6% PMs; prevalence was significantly higher among PR (63.5%) than CL (32.8%) PMs; HL mainly affected the high frequencies in the 3000-6000 Hz range and was symmetric in 68% PR PMs and in 44.5% CL PMs. Tinnitus was the most common audiological symptom, followed by hyperacusis and diplacusis. Tinnitus was almost equally distributed between PR and CL PMs; diplacusis was more common in CL than in PR PMs, while prevalence of hyperacusis was higher among PR PMs. Our review showed that PR musicians have a higher risk of developing HL compared to CL PMs; exposure to sounds of high frequency and intensity and absence of ear protection may justify these results. Difference in HL symmetry could be explained by the type of instruments used and consequent single-sided exposure.
Dementia and hearing loss share radiologic and biologic findings that might explain their coexistence, especially in the elderly population. Brain atrophy has been observed in both conditions, as ...well as the presence of areas of gliosis. The brain atrophy is usually focal; it is located in the temporal lobe in patients with hearing loss, while it involves different part of brain in patients with dementia. Radiological studies have shown white matter hyperintensities (WMHs) in both conditions. WMHs have been correlated with the inability to correctly understand words in elderly persons with normal auditory thresholds and, the identification of these lesion in brain magnetic resonance imaging studies has been linked with an increased risk of developing cognitive loss. In addition to WMHs, some anatomopathological studies identified the presence of brain gliosis in the elderly’s brain. The cause-effect link between hearing loss and dementia is still unknown
,
despite they might share some common findings. The aim of this systematic review is to analyze radiologic and biomolecular findings that these two conditions might share, identify a common pathological basis, and discuss the effects of hearing aids on prevention and treatment of cognitive decline in elderly patients with hearing loss.
Oral supplements (OS) support the immune system in fighting upper airways infection. This study aimed to analyze the effect of Difensil Immuno (DI) on the recurrence of tonsillitis and fever in ...children. A multicentric randomized clinical trial was conducted. One-hundred and twenty children with chronic tonsillitis were randomly assigned to group A, B or control. Patients in group A were treated with 10 mL of DI for 90 consecutive days, patients in group B underwent treatment with 15 mL of DI for 45 consecutive days. The following data were collected at baseline (T0), T1 and T2: tonsillitis and fever episodes, tonsillar volume, blood test results. One-way ANOVA was used to analyze within and between variances. Patients in group A and B statistically improved their clinical parameters (episode of tonsillitis and fever, tonsillar volume) when compared to control group both at T1 and T2. However, T1 variances were more consistent in group A than in group B. All patients in the study groups improved their clinical outcomes. No statistically significant variances were observed in blood parameters both at T1 and T2. Our results suggest that children treated with DI had fewer episodes of tonsillitis and fever and a reduction in their tonsillar volume.
Cochlear implant surgery in far-advanced otosclerosis can be challenging due to the degenerative process that affects the cochlea. We used OTOPLAN® to plan and define the details of surgery in a ...patient with such severe alteration of the cochlea that cochlear implant could be contraindicated. A 73-year-old man affected by bilateral far-advanced otosclerosis, previously treated by bilateral stapedotomy, presented 0% of speech discrimination using bilateral hearing aids. A unilateral cochlear implant was planned. The patient underwent radiologic investigation pre-surgery with temporal bone computer tomography, magnetic resonance imaging, and OTOPLAN. Radiology confirmed bilaterally advanced signs of fenestral and cochlear otosclerosis with large osteolytic cavities along the whole cochlea leading to the mixture of endolymph and perilymph. The OTOPLAN identified the alteration of the cochlea in detail. Based on the results of the software, we used a perimodiolar implant on the left ear. No intraoperative or post-operative surgical complications were observed. The patient was checked 6 months after surgery, he did not refer any problems and obtained 75% of speech discrimination at 65 dB. Our case suggests that OTOPLAN is a useful tool in far-advanced otosclerosis because careful planning of the surgery can positively affect the results. Despite the complexity of the anatomy, the software exactly described the real intrasurgical finding. We think that the use of OTOPLAN might improve the surgical indication.
Arachnoid cyst in the internal auditory canal is a quite rare pathology but due to its compressive action on the nerves in this district should be surgically removed. Several surgical techniques have ...been proposed but no surgeons have used the minimally assisted endoscope retrosigmoid approach for its removal.
To investigate the feasibility of using a minimally invasive endoscope assisted retro-sigmoid approach for surgical removal of arachnoid cysts in the internal auditory canal.
Minimally invasive endoscope assisted retrosigmoid approach allows to access to the internal auditory canal through a minimally invasive retrosigmoid approach that combines the use of a microscope and an endoscope. It is performed in six steps: soft tissue step, bone step, dura step, cerebellopontine angle step (performed using an endoscope and a microscope), microscope-endoscope assisted arachnoid cysts removal and closure. We tested minimally invasive endoscope assisted retrosigmoid approach for removal of arachnoid cysts in the internal auditory canal on two human cadaveric heads (specimens) of subjects affected from audio-vestibular disorders and with arachnoid cysts in the internal auditory canal confirmed by magnetic resonance imaging.
The mass was completely and successfully removed from the two specimens with no damage to the nerves and/or vessels in the surgical area.
The results of our study are encouraging and support the feasibility of using minimally invasive endoscope assisted retrosigmoid approach for removal of arachnoid cysts in the internal auditory canal. While further clinical in-vivo studies are needed to confirm the accuracy and safety of using the minimally invasive endoscope assisted retrosigmoid approach for this specific surgery, our group has successfully used the minimally invasive endoscope assisted retrosigmoid approach in the treatment of microvascular compressive syndrome, schwannoma removal and vestibular nerve resection.
Aim
We investigated if loop characteristics correlate with audio-vestibular symptoms or hemifacial spasm in patients with a vascular loop in the root entry zone (VII and VIII) and in the internal ...auditory canal.
Materials and methods
A retrospective, multicenter study analyzed 2622 consecutive magnetic resonance imaging (MRI) scans of the cerebellopontine angle of patients with asymmetric audio-vestibular symptom or hemifacial spasm; patients’ symptoms were confirmed by clinical tests. MRIs displaying vascular loops visible in the axial view were analyzed using multiplanar reconstruction. We evaluated (1) depth of penetration of the loop into the internal auditory canal (IAC); (2) largest diameter of the vessel; (3) nerve(s) involved in the vascular impingement, position of the loop relative to such nerve(s) and number of contacts between vessel and nerve(s); (4) length of such contact. The loop metrics described above were correlated with the patients’ audio-vestibular symptoms and hemifacial spasm.
Results
Three hundred ninety-nine patients displayed a loop visible in the MRI axial view and out of them only 118 displayed a direct contact between loop and nerve. The cochlear nerve was involved in a contact in 57.7%. Loops in direct nerve contact had a calibre > 0.85 mm, were located in the middle portion of the IAC, and correlated with vertigo (
p
= 0.002), tinnitus (
p
= 0.003), and hemifacial spasm (
p
< 0.001). Asymmetric sensorineural hearing loss (SNHL) correlated with number of contacts (
p
< 0.001) and length of contact (
p
< 0.05). The contact was asymptomatic in 41.5% of patients.
Conclusion
Loop characteristics may help predict whether a vascular impingement is responsible for a symptom and guide the physician to select the best treatment.
Key Points
•
A vascular loop in the internal auditory canal was observed in 18–20% of the patients in this study; whether a loop can be responsible for a compressive syndrome is still unclear in particular referred to the vestibulocochlear nerve.
•
Compression by a loop on the facial nerve causes hemifacial spasm; compression by a loop on the cochlear or vestibular nerve may cause audio-vestibular symptoms.
•
In patients with a loop, the loop calibre, the loop position, and the number of loop-nerve(s) assessed via the multiplanar MRI reconstruction technique may help assess whether the patient will manifest audio-vestibular symptoms or hemifacial spasm.
OBJECTIVES: To identify the cochlear segment in which spiral ganglion neuron (SGN) loss may more severely impact discrimination thresholds. MATERIALS and METHODS: Thirteen temporal bones from 13 ...subjects between 55 and 77 years of age were analyzed. The organ of corti was analyzed to identify the loss of hair cells, and the number of SGNs in each cochlear segment were counted. The results of the speech perception test (SPT) and pure tone audiometry (PTA) tests were collected. PTA averages for low and high frequencies were calculated. One-way analysis of variance (ANOVA), Pearson, Spearman, and multilinear regression tests were performed. RESULTS: No statistically significant correlation was identified between the patient's age and number of SGNs. Statistically significant differences were observed between the number of SGNs in the different cochlear segments (one-way ANOVA: p<0.0001) and between poor PTA average and SPT scores (negative correlation) (p=0.03). A statistically significant correlation was identified between the overall number of cochlear SGNs and SPT scores (p=0.02) and between the number of SGNs in cochlear segments I (p=0.04) and II and the SPT score (p=0.03). CONCLUSIONS: We identified that residual SGNs in the basal and middle turns of the cochlea might be determinants of speech perception. KEYWORDS: Speech perception, spiral ganglions, cochlea segmentation, word understanding
Children hospitalized in Neonatal Intensive Care Units (NICU) present an increased risk for Sensorineural Hearing Loss (SNHL) due to prematurity, hypoxia-ischemia, hyperventilation, low birth weight ...and the use of ototoxic drugs. The aim of this study was to assess the prevalence of SNHL in newborns hospitalized in a NICU using Transient Evoked Otoacoustic Emissions (TEOAE) and Automated Auditory Brainstem Responses (A-ABR) and analyze the associated risk factors. A sample of 153 newborns hospitalized in NICU underwent TEOAE, A-ABR and clinical ABR to evaluate the presence of hearing deficits. Prevalence of SNHL was calculated and odds ratio for specific risk factors was measured. One-hundred fifteen babies (86.7%) presented normal hearing at TEOAE and A-ABR. Fifteen children had a REFER response at TEOAE and a PASS response at A-ABR. Twenty-five children (16.3%) had a REFER A-ABR and were addressed to clinical ABR. A diagnosis of SNHL was made in 12 (7.8%) newborns. An increased risk of SNHL was observed in preterm children <28 weeks (p=0.0135), in children with neurological disorders (p=0.02), that underwent surgery (p=0.0002), affected from premature retinopathy (p=0.0006), craniofacial malformation (p=0.007) and that had sepsis (p=0.04). Additional risk factors for SNHL in our sample were a maternal disease during pregnancy (p=0.0011), cesarean delivery (p<0.0001) and a twin pregnancy (p<0.0001). SNHL in newborns is correlated with hospitalization in NICU. An accurate hearing screening associated to a rigorous clinical medical collection of data is necessary to promptly identify cases of SNHL in children with a special attention to those hospitalized in NICU and plan proper intervention.
The use of surgical decompression of facial hemispasm due to the loop in the internal auditory canal is not always accepted due to the risk related to the surgical procedure. Currently a new surgical ...technique allows surgeons to work in safer conditions.
To report the results with endoscope-assisted retrosigmoid approach for facial nerve microvascular decompression in hemifacial spasm due to neurovascular conflict. The surgical technique is described.
We carried out a prospective study in a tertiary referral center observing 12 (5 male, 7 female) patients, mean age 57.5 years (range 49–71) affected by hemifacial spasm, that underwent to an endoscope assisted retrosigmoid approach for microvascular decompression. We evaluated intra-operative findings, postoperative HFS resolution and complication rates.
Hemifacial spasm resolution was noticed in 9/12 (75%) cases within 24h after surgery and in 12/12 (100%) subjects within 45 days. A significant (p<0.001) correlation between preoperative historical duration of hemifacial spasm and postoperative recovery timing was recorded. Only 1 patient had a complication (meningitis), which resolved after intravenous antibiotics with no sequelae. No cases of cerebrospinal fluid leak, facial palsy or hearing impairment were recorded. Hemifacial spasm recurrence was noticed in the only subject where the neurovascular conflict was due to a vein within the internal auditory canal.
The endoscope assisted retrosigmoid approach technique offers an optimal visualization of the neurovascular conflict thorough a minimally invasive approach, thus allowing an accurate decompression of the facial nerve with low complication rates. Due to the less invasive nature, the procedure should be considered in functional surgery of the cerebellar pontine angle as hemifacial spasm treatment, specially when the procedure is performed by an otolaryngologist.
O uso de descompressão cirúrgica do espasmo hemifacial devido ao loop no canal auditivo interno nem sempre é aceito devido ao risco relacionado ao procedimento cirúrgico. Atualmente, uma nova técnica cirúrgica permite trabalhar em condições seguras.
Relatar os resultados que obtivemos com a abordagem retrosigmóidea assistida por endoscopia para a descompressão microvascular do nervo facial em casos de espasmo hemifacial devido a conflito neurovascular. A técnica cirúrgica é descrita.
Realizamos um estudo prospectivo em um centro de referência terciária observando 12 pacientes (5M, 7F), com média de idade de 57,5 (intervalo 49-71) anos com espasmo hemifacial submetidos a uma abordagem retrosigmóide assistida por endoscopia para descompressão microvascular. Foram avaliados os achados intraoperatórios, a resolução pós-operatória do espasmo hemifacial e as taxas de complicações.
A resolução do espasmo hemifacial foi observada em 9/12 (75%) dos casos nas 24 horas após a cirurgia e em 12/12 (100%) dos indivíduos até 45 dias. Uma correlação significativa (p<0,001) entre a duração do histórico pré-operatório de espasmo hemifacial e o tempo de recuperação pós-operatório foi registrado. Apenas um paciente apresentou uma complicação (meningite), que foi resolvida após administração de antibióticos por via intra venosa sem sequelas. Nenhum caso fístula liquórica, paralisia facial ou deficiência auditiva foi registrado. A recorrência do espasmo hemifacial foi observada em único indivíduo em quem o conflito neurovascular foi causado por um vaso no interior do canal auditivo interno.
A técnica da abordagem retrosigmóidea assistida por endoscopia oferece uma ótima visualização do conflito neurovascular através de uma abordagem minimamente invasiva, permite assim uma descompressão precisa do nervo facial com baixas taxas de complicações. Por ser menos invasivo, o procedimento deve ser considerado na cirurgia funcional do ângulo pontocerebelar como tratamento de espasmo hemifacial, especialmente quando o procedimento é feito por um otorrinolaringologista.
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