Investigation of serum calcium and vitamin D levels in superior semicircular canal dehiscence syndrome: A case control study

Objective: It remains unknown whether calcium metabolism has any effect on the clinical presentation of superior semicircular canal dehiscence(SSCD). Our aim was to analyse the adjusted calcium and vitamin D levels in SSCD patients compared to a control group.Methods: This was a prospective case-control study performed in a tertiary referral center, university teaching hospital in the UK. It included all new patients with SSCD seen in a dedicated skull base clinic over a 5-year period(2015-2019) compared to a gender and age matched control group. The main outcome of the study was adjusted calcium and Vitamin D levels between the two groups.Results: A total of 31 SSCD patients were recruited with a matched number of control patients. The mean Vitamin D level on the SSCD group was 44.8 nmoL/l(SD: 20.8) compared to 47.5 nmoL/l(SD: 27.4) on the control group(p = 0.702). Mean Adjusted calcium level was 2.34 mmoL/l(SD: 0.7) for SSCD compared to2.41 mmoL/l(SD: 0.11) for controls(p = 0.01), being within normal limits for both the SSCD and the control group.Conclusion: Our study did not identify a link between Vitamin D levels and presence of SSCD. Normal adjusted calcium values were found in both groups. Despite that a statistically significant lower calcium level was found in the SSCD group which could indicate that suboptimal levels of calcium may affect the micro-environment of the otic capsule at the SSC region.

An evidenced-based diagnostic tool for superior semicircular canal dehiscence syndrome

Purpose:To construct a symptoms-based prediction tool to assess the likelihood of superior canal dehiscence(SSCD)on high-resolution CT.Materials and methods:Mathematical modeling was employed to predict radiologic evidence of SSCD at a tertiary neurotology referral center.Results:A total of 168 patients were included,of which 118 had imaging-confirmed SSCD.On univariate analysis significant predictors of SSCD presence were:sound/pressure-induced vertigo(p?0.006),disequilibrium(p?0.008),hyperacusis(p?0.008),and autophony(p?0.034).Multivariate analysis enabled a 14-point symptom-weighted tool to be developed,wherein a score of6 raised the suspicion of SSCD(70%likelihood of being present),R2?0.853.Conclusions:The likelihood of SSCD on CT scan can be determined with a high degree of certainty based on symptoms recorded at presentation.Using the evidenced-based diagnostic tool validated herein,a score6 with any symptom combination justifies ordering a CT scan.

Quick repositioning maneuver for horizontal semicircular canal benign paroxysmal positional vertigo

Objective:To investigate the efficacy of quick repositioning maneuver for horizontal semicircular canal benign paroxysmal positional vertigo (H-BPPV). Methods:Clinical data of 67 patients with H-BPPV who underwent quick repositioning maneuver in our hospital from July 2009 to November 2014 were retrospectively analyzed. The maneuver involved rotating the patient in the axial plane for 180? from the involved side towards contralateral side as quickly as possible. Results:Complete symptom resolution was achieved in 61 patients (91.0%) at one week and in 64 patients (95.5%) at 3 months post-treatment. During the repositioning maneuver process, there were no obvious untoward responses except transient nausea with or without vomiting in a few patients. Conclusion:The results indicate that the quick repositioning maneuver is an easy and effective alternative treatment in the management of H-BPPV. Copyright ? 2015 The Authors. Production & hosting by Elsevier (Singapore) Pte Ltd On behalf of PLA General Hospital Department of Otolaryngology Head and Neck Surgery. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Elastic-plastic behavior of a semicircular frame being pressed against a rigid plane

As a simplified structural model, a semicircular frame is used to study the crashworthiness behavior of an aircraft fuselage. The quasi-static large elastic-plastic deformation of a semicircular frame in the process of its being pressed against a rigid ground is analyzed. First, based on the linear elastic assumption, the quasi-static large deformation contact process of the frame can be divided into three phases, i.e., point contact, line contact and post-buckling. By means of a shooting method, the relations between the displacement and contact force as well as the distribution of bending moment in the three phases are obtained. Then, by assuming an elastic, perfectly-plastic moment-curvature relationship for the semi-circular frame, the contact process is analyzed in detail to reveal the plastic collapse mechanism, the traveling of plastic hinge and the force-displacement relationship. In order to verify the analysis, a preliminary experiment was conducted, in which two types of half rings with clamped ends were pressed by a rigid plate. In addition, a numerical simulation is also conducted by employing ABAQUS to analyze both rectangular cross-sectional beam and I-beam. Finally, the theoretical predictions are compared with the experimental results and numerical solutions, showing that the elastic-plastic analysis can predict the contact process very well.

NUMERICAL AND EXPERIMENTAL INVESTIGATION OF FLOW OVER A SEMICIRCULAR WEIR

The water flow over a semicircular weir is investigated numerically and experimentally in this paper. The numerical model solves the Reynolds equation for a mean flow field with thek-ε-turbulent model. To trace the motion of the free surface, the COF method with geometric reconstruction is employed. The velocity of the flow is measured by means of LDV technique. Four types of flow patterns, the position of the separation and reattachment point, the distribution of shear stress on the bed at downstream of the weir are presented and discussed. The numerical results agree well with the experiment data.

Temporal bone anatomy characteristics in superior semicircular canal dehiscence

Introduction: Superior semicircular canal dehiscence(SCD) remains difficult to diagnose despite advances in high-resolution computed tomography(HRCT) imaging. We hypothesize possible associations between gross temporal bone anatomy and sub-millimeter pathology of the semicircular canals, which may supplement imaging and clinical suspicion. This pilot study investigates differences in gross temporal bone anatomic parameters between temporal bones with and without SCD.Methods: Records were reviewed for 18 patients referred to an otology clinic complaining of dizziness with normal caloric stimulation results indicative of non-vestibular findings. Eleven patients had normal temporal bone anatomy while seven had SCD. Three-dimensional reconstruction of every patient's temporal bone anatomy was created from patient-specific computational tomography images. Surface area(SA),volume(V), and SA to V ratios(SA:V) were computed across temporal bone anatomical parameters.Results: SCD temporal bones have significantly smaller V, and larger temporal bone SA. Mean(±SD) V was 21,484 ± 3,921 mm^3 in temporal bones without SCD and 16,343 ± 34,471 mm^3 for those with SCD. Their respective SA were 13,733 ± 1,603 mm^2 and 18,073 ± 3,002 mm^2.Temporal bone airspaces and lateral semicircular canals did not demonstrate significant differences where SCD was and was not present. Plots of MV_(warm)response against computed SCD temporal bone anatomic parameters(SA, V and SA:V) showed moderate to strong correlations:temporal bone SA:V(r= 0.64), temporal bone airspace V(r= 0.60), temporal bone airspace SA(r= 0.55), LSCC SA(r= 0.51), and LSCC-toTM Distance(r= 0.65).Conclusions: This analysis demonstrated that SCD is associated with decreased temporal bone volume and density. The defect in SCD does not appear to influence caloric responses.

Study of Partial Coefficients for Design of Semicircular Breakwaters

In the present study, the reliability design of semicircular breakwater is based on the verification of the rules defined by standard specifications, where partial coefficients are introduced to ensure safety. The reliability of the semicircular breakwaters has been analyzed by using the Hasofer-Lind method to determine the reliability index of structure that has correlated loads, utilizing the long-term observed wave data at a given place. The relation curve between reliability index and safety factor in the traditional design method, as well as the relationships between reliability index and partial coefficients, have been obtained. This paper proposes values of partial coefficients for the design expression of semicircular breakwaters in the cases of anti-sliding and anti-overturning.

Scattering of SH-wave from interface cylindrical elastic inclusion with a semicircular disconnected curve

Scattering of SH wave from an interface cylindrical elastic inclusion with a semicircular disconnected curve is investigated. The solution of dynamic stress concentration factor is given using the Green＇s function and the method of complex variable functions. First, the space is divided into upper and lower parts along the interface. In the lower half space, a suitable Green＇s function for the problem is constructed. It is an essential solution of the displacement field for an elastic half space with a semi-cylindrical hill of cylindrical elastic inclusion while bearing out-plane harmonic line source load at the horizontal surface. Thus, the semicircular disconnected curve can be constructed when the two parts are bonded and continuous on the interface loading the undetermined anti-plane forces on the horizontal surfaces. Also, the expressions of displacement and stress fields are obtained in this situation. Finally, examples and results of dynamic stress concentration factor are given. Influences of the cylindrical inclusion and the difference parameters of the two mediators are discussed.

A METHOD USING THE RECIPROCAL THEOREM TO SOLVE THE BENDING OF THIN ELASTIC SEMICIRCULAR PLATES

The bending of the thin elastic semicircular plates, because of its complicated boundary conditions, brings some difficulties for us to obtain its solution. This paper applies the reciprocal theorem to propose a general simple convenient method to obtain the transverse deflectional equations of the plates.

The Effects of Vestibular Rehabilitation after Bilateral Superior Semicircular Canal Dehiscence: A Case Report

Background and Purpose: Despite the strong body of evidence for vestibular rehabilitation, research is lacking for effective clinical management of patients with superior semicircular canal dehiscence (SSCD) and endolymphatic hydrops (EH). The purpose of this case report is to describe the effects of physical therapy in the treatment of a patient diagnosed with bilateral SSCD. Case Description: The patient was a 56-year-old woman with a long-standing otologic history involving bilateral SSCD and EH. The patient’s body structure and function impairments include constant headaches, dizziness with head rotation and eye movements, sensitivity to sounds and lights, and instability during gait. Her activity limitations include lower extremity dressing, driving, and playing her flute. Her participation restrictions include taking part in social gatherings, going to church, driving longer than 30 minutes, playing with her dogs, and teaching flute lessons. Interventions: Specific interventions included vestibular habituation and adaptation exercises, balance and gait training, and patient education. Physical therapy services were provided for approximately 11 weeks with a frequency of two times per week. Outcomes: After eleven weeks of physical therapy, the patient made improvements on the Lower Extremity Functional Scale (43/80 to 52/80), the Dynamic Gait Index (19/24 to 24/24), the Dizziness Handicap Inventory (86/100 to 68/100), and the Sharpened Romberg (2 seconds to >30 seconds). The patient improved in all her activity limitations and participation restrictions. She was able to play her flute for 20-minute intervals, play with her dogs, partake in social gatherings, and drive for 5 hours without symptoms. The patient had plans to pursue surgical intervention within the next year. Discussion: For a patient with a complex otologic history and a current diagnosis of bilateral SSCD, vestibular rehabilitation was an effective management option. The information from this case can be used to guide the effective treatment of similar patients diagnosed with vestibular dysfunction.

Complex nystagmus in traumatic benign paroxysmal positional vertigo:A case study on the critical value of knowing semicircular canal excitation and inhibition patterns

A 73-year-old female presented to the emergency department with chief complaint of dizziness after sustaining a fall one month prior to dizziness onset.Although careful examination of eye movement patterns during positional testing was attempted at varying stages of her inpatient admission,her complex nystagmus patterns as a result of traumatic benign paroxysmal vertigo were difficult to manage.In particular,the nystagmus pattern from this case suggests the BPPV was variable and affecting either 1)left posterior semicircular canal(pSCC)exclusively 2)left pSCC and right anterior semicircular canal,3)left and right pSCC canal.This case illustrates the importance of two critical details;positional testing should include observing nystagmus with fixation removed and an experienced clinician should be involved as early as possible.

Bilateral Superior Semicircular Canal Dehiscence without Signs of Vestibular Involvement about a Case

Superior semicircular canal dehiscence (SSCD) is a rare entity recently described whose typical clinical symptomatology is represented by dizziness triggered by a variation of pressure. We reported a case of SSCD which was diagnosed thanks to computed tomography (CT) scan of the petrous bone conducted systematically in front of mixed deafness with normal eardrum. The SSCD was bilateral and was revealed by mixed deafness on the left side and perception deafness on the right with a normal eardrum without the notion of vertigo. The cervical vestibular evoked myogenic potential (cVEMP) and an ultra-high resolution CT scan of the petrous bones in coronal and sagittal sections allowed the diagnosis. The SSCD should be considered in the presence of any conductive or mixed hearing loss with a normal eardrum. The CT scan in coronal and sagittal submillimetric sections allows the diagnosis.

Subtemporal Extradural Approach for Dehiscence of the Superior Semicircular Canal: Surgical Technique and Results in Three Consecutive Patients

We describe three patients with severe disabling symptoms of unilateral dehiscence of the superior semicircular canal (DSSC) who had surgical treatment. Each patient underwent a unilateral subtemporal extradural approach with resurfacing the DCCS. In all 3 patients, all symptoms were completely resolved and remained symptom free on the long term. There were no postoperative complications. Only one patient experienced a temporary CSF hypotension syndrome and some dizziness. The pseudo-conductive hearing loss improved or resolved in all patients. Surgical treatment should be considered in patients with severe, disabling DSSC symptoms. Surgical resurfacing of the DSSC is a safe and rewarding surgical technique. The long term success rate regarding the elimination of the pseudo-conductive hearing loss and resolution of vestibular symptoms outweigh the potential surgical risks of this technique in these patients.

良性阵发性位置性眩晕患者七年大数据回顾分析

目的良性阵发性位置性眩晕(BPPV)是最常见的外周性前庭疾病,但目前我国尚缺乏对BPPV大样本数据的回顾性分析,本研究旨在为BPPV患者家庭疾病预警和防范提供相应的理论依据。方法回顾性选取2014年6月—2021年6月中国人民解放军总医院眩晕诊疗中心数据库中眩晕患者45807例的临床资料,其中符合BPPV诊断患者5883例,根据其类型分类,统计患者年龄、性别、就诊时间、首诊BPPV类型、复诊BPPV类型等信息。使用Python 3.7进行数据可视化。结果BPPV患者中,女性3909例,男性1974例,50~59岁人群BPPV患者最多,且各BPPV类型中,女性患者比例均高于男性患者。所有眩晕患者位置性试验(+)阳性率为12.8%。不同类型BPPV比例中后管BPPV比例为64.5%,水平管BPPV比例为30.9%。有1092例BPPV复诊记录,首次诊断BPPV至复诊阴性有411例,234例患者BPPV类型在2~6次的就诊过程中有改变,BPPV类型转换比较常见的是左右耳PC-BPPV之间变化(71例)。结论本研究大数据显示,BPPV患者主要分布在50岁左右人群,女性患者约为男性的2倍。LC-BPPV患者比例远高于前期研究数据,约占所有BPPV患者的30.9%。在长期随访中,除大部分患者的BPPV类型没有发生变化外,主要的耳石变化存在后管侧别之间、后管与水平管之间进行转换的趋势。

拖拉机多路阀节流槽动态特性研究与试验

为优化部分拖拉机多路阀流量特性、减小压差等问题,设计一种具有U-半圆形节流槽结构的拖拉机多路阀,通过仿真试验研究U-半圆形节流槽拖拉机多路阀的动态特性。结果表明:U-半圆形节流槽出口流量呈现先小后大再小的特点。多路阀出口稳态流量为113 L/min,流量变化稳定无冲击,控制特性好。制定U-半圆形节流槽拖拉机多路阀试验方案,通过试验得出阀口压差随着阀芯位移的增大而减小,阀口最小压差为1.2 MPa;测得多路阀最大泄漏量为10.5 mL/min,满足泄漏指标。从而验证U-半圆形节流槽多路阀流量变化稳定,内泄漏量小。

桂枝加葛根汤联合当归芍药散治疗良性位置性眩晕的效果

目的 探讨桂枝加葛根汤联合当归芍药散治疗良性位置性眩晕(benign paroxysmal positional vertigo,BPPV)的效果。方法 选取2021年2月-2023年8月收治的80例老年后半规管BPPV痰瘀互阻证患者,按照掷硬币法分为2组,对照组(n=40)采取常规西药治疗,观察组(n=40)另用桂枝加葛根汤联合当归芍药散治疗,比较2组疗效。结果 治疗7 d、14 d后,观察组中医证候积分较对照组低(P<0.05)。14 d治疗后,观察组眩晕评分、血液流变学指标、血清同型半胱氨酸(homocysteine,Hcy)水平均优于对照组(P<0.05)。治疗后,观察组脑血流动力学较对照组优(P<0.05)。2组在治疗期间均未出现头痛、乏力不良反应。结论 对老年后半规管BPPV痰瘀互阻证患者采取桂枝加葛根汤联合当归芍药散治疗,可明显减轻患者眩晕症状和中医证候积分,改善其血液流变学和脑血流动力学,值得推广。

基于位移等代法的深部直墙半圆拱形隧洞松动圈厚度预测

【目的】位移等代法是在工程实践中被广泛应用的一种等效圆法。为进一步探索该方法在深部非均匀应力场下预测松动圈厚度的工程效果,并建立具有工程适用性的等效圆半径计算公式,【方法】选取深部隧洞常采用的直墙半圆拱形断面为研究对象,根据位移等代法基本原理,利用FLAC~(3D)数值模拟和理论计算相结合的方式,建立了侧压系数λ为1.1~1.5,跨高比b_0/h为1.3~1.5条件下的等效圆半径函数关系式,并应用到江西曲江某煤矿水仓围岩的松动圈厚度预测。【结果】结果显示:根据等效圆公式计算出的水仓围岩松动圈的纵轴厚度为1.41 m,横轴为1.20 m,呈椭圆形;现场实测的松动圈也呈椭圆形,厚度平均值在1.15~1.45 m,其中最大均值在纵轴1.45 m,最小均值在横轴为1.15 m。理论预测值与实测值相吻合。【结论】结果表明:位移等代法适用于深部软岩松动圈厚度预测;所建等效圆半径公式具有良好的工程适用性,可为评价和预测类似隧洞工程松动圈厚度提供一种简化的、可借鉴的方法和思路。

病程对水平半规管良性阵发性位置性眩晕复位后残余症状的影响

目的 探讨不同病程对水平半规管良性阵发性位置性眩晕(horizontal canal benign paroxysmal positional vertigo,HC-BPPV)患者成功复位后残余症状的影响。方法 选取2021年7月—2022年3月上海交通大学医学院附属新华医院耳鼻咽喉头颈外科收治的HC-BPPV患者49例,根据发病至复位时间分为短病程组33例和长病程组14例。所有患者均采用转椅辅助下的Barbecue或Gufoni耳石复位治疗,成功复位后7~10 d进行复诊,复位前后均采用眩晕障碍量表(dizziness handicap inventory,DHI)进行评估,比较两组复位前后DHI各维度评分及总分差异。结果 复位前后,长病程组DHI总分均高于短病程组,差异有统计学意义(P<0.05)。复位前,长病程组DHI-F评分高于短病程组,差异有统计学意义(P<0.05);复位后,长病程组DHI-F评分、DHI-P评分、DHI-E评分均高于短病程组,差异均有统计学意义(P<0.05)。复位前后,两组DHI各维度评分差值及总分差值比较,差异均无统计学意义(P>0.05)。结论HC-BPPV复位后,出现残余症状的风险与复位前病程有关,病程越长,复位后出现残余症状的风险越大,残余症状可表现在躯体功能、社会功能及心理障碍等方面。

不同责任半规管BPPV与主诉症状关系分析

目的分析确诊良性阵发性位置性眩晕(BPPV)患者的位置性眩晕主诉特征,以及主诉症状与BPPV责任半规管定位诊断的相关性。方法对2022年2-3月因位置性眩晕就诊于该院患者100例完成详细病史问卷调查,以视频眼震图位置试验进行BPPV客观定位诊断,分析确定诊断BPPV与病史主诉的关系。结果100例患者中以坐起-躺下、左右翻身为眩晕主要主诉者分别为39、56例,两者分辨不清5例;位置试验阳性75例,其中BPPV确定诊断63例,其他前庭周围性眩晕12例。分析63例确定诊断BPPV患者的主诉症状,以坐起-躺下眩晕确诊垂直、水平半规管BPPV的灵敏度和特异度分别为70.7%和94.4%、5.6%和29.3%,以左右翻身眩晕确诊水平、垂直半规管BPPV的灵敏度和特异度分别为94.4%和70.7%、29.3%和5.6%。进一步分析63例BPPV患者其位置性眩晕的首发体位,以坐起-躺下者确诊垂直、水平半规管BPPV的灵敏度和特异度为76.9%和55.6%、44.4%和23.1%,左右翻身者确诊水平、垂直半规管BPPV的灵敏度和特异度为55.6%和76.9%、23.1%和44.4%。对30例可明确表述眩晕诱发较重体位侧别的BPPV患者进行分析,右侧位为较重侧13例,左侧位为较重侧17例,余33例对诱发眩晕的左右侧分别描述不清。结论位置性眩晕患者的主诉症状中,“坐起-躺下”和“左右翻身”性眩晕主诉分别对垂直、水平半规管BPPV诊断的灵敏度和特异度高,符合Ewald′s定律;而首发体位及症状较重的体位侧别,对BPPV责任半规管侧别定位诊断的灵敏度和特异度均不高。位置性眩晕患者主诉症状对BPPV快速筛查具有一定的临床价值,确定定位诊断要依靠位置试验。