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Brachycephaly in French bulldogs and pugs is associated with narrow ear canals 短头犬法国斗牛犬和巴哥犬与耳道狭窄相关性 作者：Tanja Topfer, Claudia Kohler, Sarah Rosch and Gerhard Oechtering 翻译：王帆 Background–Brachycephalic dog breeds have multiple skull malformations which may lead to anatomical changes in the external auditory canal. It is our frequent observation that in the otoscopic examination of the external ear in these breeds we are unable to visualise the tympanic membrane as a consequence of extreme narrowing of the proximal ear canal. Additionally brachycephalic dogs reportedly are predisposed to otitis externa (OE) and otitis media. Objectives–To characterizse the transition of the cartilaginous ear canal to the bony meatus acusticus externus using computed tomography (CT) and to investigate a possible association with OE in brachycephalic dogs. Materials and methods–Seventy-five client-owned dogs [pugs (n = 20), French bulldogs (n = 55)] were included and assessed for OE using an owner questionnaire and otoscopic and cytological examinations. In dorsal plane CT scans, the diameter of the porus acusticus externus was measured using novel methodology. The results were compared with a normocephalic control group without preexisting otological disorders. Results–Brachycephalic dogs had a significantly smaller porus acusticus externus diameter (2.6 mm) than normocephalic dogs (5.0 mm). Of the brachycephalic dogs, 32% had OE yet this was not statistically significantly related to the diameter of the porus acusticus externus. Middle ear effusion (44%) and narrowing of the external ear canal (82.6%) were significantly more frequent in brachycephalic dogs. Only five of 150 eardrums could be visualised otoscopically. Conclusions and clinical relevance–Malformation of the porus acusticus externus causes severe stenosis of the proximal ear canal in brachycephalic dogs. A connection between stenosis of the external auditory canal and OE could not be confirmed. 摘要 背景-短头犬品种具有多发性颅骨畸形, 可能导致外耳道解剖结构改变。我们经常观察到, 在这些品种的外耳耳镜检查中, 由于近端耳道极度狭窄, 我们无法观察到鼓膜。此外, 据报告短头犬易患外耳炎(OE)和中耳炎。 目的-使用计算机断层扫描(CT)观察耳道软骨向骨性外耳道的转变, 并研究短头犬OE与之可能存在的相关性。 材料和方法-纳入75只家养犬[巴哥犬(n = 20),法国斗牛犬(n = 55)], 并使用主人问卷以及耳镜和细胞学检查评估OE。在背侧平面CT扫描中, 采用新方法测量外耳道孔径。将结果与无耳病病史的正常头部对照组进行比较。 结果-短头犬的外耳道孔径(2.6 mm)显著小于正常头部犬(5.0 mm)。在短头犬中, 32%患有OE, 但这与外耳道孔径无统计学显著相关性。中耳积液(44%)和外耳道狭窄(82.6%)在短头犬中明显较多。150个鼓膜只有5个可以通过耳镜观察到。 结论和临床相关性-外耳道畸形导致短头犬近端耳道严重狭窄。无法证实外耳道狭窄与OE之间的联系。 Introduction 介绍 Upper airway obstruction has been described frequently in brachycephalic dogs. These breeds have several abnormalities of the skull, including deformities of the nasal cavity, frontal sinus and orbita. Several studies have demonstrated that brachycephalic syndrome involves more than the upper respiratory tract, and includes the spine, skin, eyes and teeth. In addition, brachycephalic dogs appear to be predisposed to fluid accumulation in the tympanic bullae. Computed tomography (CT) and magnetic resonance imaging (MRI) examinations of the head in bulldogs and pugs frequently have detected sub-clinical tympanic bulla changes, with a reported prevalence of ≤36%. French bulldogs (FB) and pugs have more rostrally located tympanic bullae, with thicker walls and a smaller volume than other breeds. 短头犬常见上呼吸道阻塞。这些品种多个畸形头骨，包括鼻腔、额窦和眼眶的畸形。多项研究表明，短头综合征不仅涉及上呼吸道，还包括脊柱、皮肤、眼睛和牙齿。此外，短头犬似乎更容易在鼓泡积液。斗牛犬和巴哥犬头部的计算机断层扫描(CT)和磁共振成像(MRI)检查经常发现亚临床症状的鼓泡病变，据报道发病率为≤36%。法国斗牛犬(FB)和巴哥犬鼓泡向喙部更突出，与其他品种相比，鼓室壁厚，容积小。
Little is currently known about whether the described anatomical changes also extend to the external auditory canal. Otoscopic examination of these breeds repeatedly has shown extreme narrowing of the external auditory canal and problems with eardrum visualisation (Figure 1). These changes repeatedly have been found in both symptomatic and asymptomatic dogs in our clinic. Unfortunately, these changes complicate the diagnosis of middle ear diseases and the treatment of inflammation in the external ear canal, because, for example, myringotomy is not possible under video-otoscopic view. Therefore, it is important to determine the anatomical cause of the stenosis. 解剖改变是否也延伸到外耳道目前所知甚少。这些品种的耳镜检查经常显示外耳道极度狭窄，鼓膜看不到(图1)。我们的临床中，无论是有症状的犬还是无症状的犬，都经常发现这些变化。不幸的是，这些变化使诊断中耳疾病和治疗外耳道炎症复杂化，因为，例如，在视频耳镜下，无法对鼓膜切开术进行观察。因此，明确狭窄的解剖学病因很重要。
The prevalence of otitis externa (OE) in dogs ranges from 10 to 20%; however, in brachycephalic dogs, the percentage appears to be significantly higher. The causes of ear disease usually are multi-factorial and it is unclear how significant a factor stenosis of the ear canal is in these breeds. 犬外耳炎(OE)患病率为10 - 20%;然而，在短头犬中，这一比例似乎要高得多。耳病病因通常是多因素的，目前还不清楚这些品种的耳道狭窄的因素有多重要。
The objectives of the present study were as follows: (i) to evaluate the acoustic meatus in brachycephalic dog breeds, particularly the porus acusticus externus, using CT images, and to compare these findings with a group of normocephalic dogs, and (ii) to determine the presence of and possible association with OE by means of otoscopic and cytological findings. 本研究的目的如下:(i)利用CT图像评估短头犬的耳道，特别是外耳道，并将这些结果与一组正常头型犬进行比较;(ii)通过耳镜和细胞学检查，确定OE的存在及其与OE的可能关联。
Materials and methods 材料和方法 Ethical approval was not required because CT and otological examination were part of our standard work-up for the brachycephalic syndrome. By answering the questionnaire, all owners agreed to become part of the study.
不需要伦理批准，因为CT和耳科检查是我们短头综合征标准检查的一部分。通过回答问卷，所有宠主同意研究。
Study population 研究对象 A prospective group of two breeds of brachycephalic dogs (FB and pugs) were examined. All brachycephalic dogs were referred to the Ear, nose and throat (ENT) Unit of the Small Animal Department, University of Leipzig, for surgical correction of brachycephalic airway syndrome. The dogs’ owners completed an anamnestic questionnaire and gave consent to participate in this study.
我们对两个品种的短头犬(FB和巴哥犬)进行了研究。所有短头犬转诊至莱比锡大学小动物系耳鼻喉科（ENT），接受短头气道综合征的手术矫正。宠主完成了一份记忆问卷，并同意参与这项研究。
The dogs were anaesthetised for further diagnosis. After a CT examination of the head with special attention to the air-filled structures such as the nose, nasopharynx, middle ear and auditory canal, the upper airways and the external auditory canals were examined endoscopically, and swab samples were taken for cytological examination. This procedure is part of our standardised work-up before airway surgery for brachycephalic syndrome. 犬被麻醉以作进一步诊断。对头部进行CT检查，特别注意鼻、鼻咽、中耳和耳道等充满空气的结构，内窥镜检查上呼吸道和外耳道，拭子采样进行细胞学检查。这个程序是我们短头综合征气道手术前标准化检查的一部分。
Retrospective image data of normocephalic dogs were used for the comparison of CT measurements. The selection criterion was a body mass of 6–16 kg. The exclusion criteria were anamnestic indications for the presence of otitis and other ear pathologies such as trauma or neoplasia. 采用正常头型犬的回顾性图像数据进行CT测量的比较。选择标准为体重6-16kg。排除标准为存在耳炎和其他耳病如创伤或肿瘤。
Questionnaire and otoscopic and cytological examination 问卷和耳镜及细胞学检查 All brachycephalic animals were assessed for the presence of OE using three evaluation criteria: an owner questionnaire and otoscopic and cytological examinations of the external ear canals. If a positive response to two or more criteria was given, the dog was classified as having OE. Based on these results the dogs were divided into two groups: otitis externa (OE) and non-otitis externa (N-OE). 使用三个评价标准评估所有短头动物是否存在OE:宠主问卷和外耳道耳镜和细胞学检查。如果对两个或两个以上的标准有确定存在，犬被归类为OE。将实验犬分为外耳炎(OE)组和非外耳炎(N-OE)组。
All dog owners were given a questionnaire (see Supporting information, Appendix S1) asking about present and past clinical signs of OE and otitis media (OM), such as head shaking, scratching and ear pain, and any concurrent dermatological signs and treatment history for otitis. If two or more of the eight questions were answered positively, the evaluation criterion questionnaire was rated as abnormal. 所有的宠主都得到了一份问卷(参见附录S1)，询问了OE和中耳炎(OM)的当前和既往的临床症状，如甩头、搔抓和耳痛，以及任何同时出现的皮肤病症状和耳炎治疗史。如果8个问题中有2个或2个以上得到肯定回答，则评价标准问卷被评为异常。
All dogs were anaesthetised for CT, otoscopic examination and sample collection using a standardised anaesthetic protocol. 所有犬麻醉后进行CT、耳镜检查和样本采集，采用标准化麻醉方案。
The swab specimens (nonsterile cotton-tipped applicator) for cytological examination were obtained from the junction of the vertical and horizontal ear canals with 360° rotation, rolled onto a glass microscope slide, air-dried and stained using a modified Wright’s stain (Henry Schein; Melville, NY, USA). Stained slides were inspected first under 940 magnification to identify a representative area (Axios-kop 20, Carl Zeiss; Jena, Germany). Samples were obtained by one investigator; they were then blinded and evaluated microscopically by another independent examiner blinded to the otoscopic results. During this examination, 10 oil immersion fields (OIF) (*1,000) were counted in areas with optimal layer thickness without artifacts, and the average number of neutrophils, yeast and bacteria per sample then was calculated. If five or more yeast cells or cocci per OIF, or one or more rod or neutrophilic granulocytes per OIF were observed, the evaluation criterion cytology was rated positive. 用于细胞学检查的拭子样本(非无菌棉签)从垂直和水平耳道连接处360度旋转采样，滚到玻璃显微镜载玻片上，风干后使用改良的Wright染色。染色玻片首先在40倍放大下检查以确定一个代表区域。样本由一名调查人员采集;然后对他们进行盲法检查，由另一名独立审查员对耳镜检查结果进行显微镜检查。在检测过程中，在无伪影的最佳层厚区域计算10个油浸视野(OIF)(1000倍)，然后计算每个样本的中性粒细胞、酵母菌和细菌的平均数量。如果在每个OIF中观察到5个或5个以上的酵母菌或球菌，或在每个OIF中观察到一个或多个杆菌或中性粒细胞，则细胞学评价标准为阳性。
Otoscopic examination was performed using a rigid endoscope [Hopkins telescope (0°, 2.7° and 18 cm), Karl Storz; Tuttlingen, Germany). The course of the entire examination was documented (Image1 S with three-chip full HD camera head TH100; Karl Storz), stored digitally (AIDA, release 1.3, 100–240 VAC, 50–60 Hz; Karl Storz), and evaluated using the Otitis Index Score (OTIS3). Videos were obtained by one investigator and then blind-evaluated by another examiner independently of the cytological results. Here, the presence of the clinical parameters erythema, oedema/swelling, erosions/ulceration, and exudate was documented, and their severity was graded from 0 to 3 (0, none; 1, mild; 2, moderate; 3, severe). The number of all parameters formed the total clinical score (from 0 to 12). Clinical scores ≥4 differentiated those with abnormal endoscopic findings from healthy ears. Additionally, the unobstructed view of the eardrum, its integrity and the presence of hair in the ear canal were documented. 耳镜检查采用硬质内窥镜。记录整个检查过程，数字存储，并使用耳炎指数评分(OTIS3)进行评估。视频由一名研究者获得，然后由另一名审查员独立于细胞学结果进行盲法评估。这里记录了临床参数红斑、水肿/肿胀、糜烂/溃疡和分泌物，其严重程度从0到3级(0，无;1、轻度;2、中度;3、重度)。所有参数的分数构成了临床总分(0-12)。临床评分≥4分将内窥镜检查结果异常的耳与健康的耳区分开。此外，还记录了通透可见耳道鼓膜，其完整性和耳道中毛发的存在。
Computed tomography 计算机断层扫描 In all dogs, CT of the head was performed preoperatively for the planning of intranasal surgery for brachycephalic syndrome. 所有犬术前均进行头部CT，以规划短头综合征鼻内手术。
A multi-line spiral CT (Mx8000 Brilliance, 6-line, Philips Healthcare; Hamburg, Germany) was used for examination of the head and neck region. The animals were placed in sternal recumbency, and the upper jaw was fixed with a positioning aid to align the hard palate parallel to the table. The field of view extended from the nasal planum to the first cervical vertebra. The slice thickness was 1 mm, with 200 mAs, 120 kV and automatic dose adjustment, for the pitch 0.6 and 0.5 increments on a modified lung window (WL –300, WW 2,500) from reconstructed dorsal plane images. IntelliSpacePortal 11 (Koninklijke Philips N.V.; Eindhoven, the Netherlands) was used to display and evaluate the soft tissue and bone structure images. For the measurement, the level was chosen in which the junction to the vertical part of the auditory canal and eardrum was clearly visible, and the horizontal part of the acoustic meatus could be seen in its entire length and width. 一台多线螺旋CT用于头颈部检查。动物胸骨平卧保定，上颌固定与定位辅助对齐硬腭与台面平行。视野从鼻平面延伸到第一颈椎。在重建的背平面图像上，对修改后的肺窗(WL -300, WW 2500)进行间距0.6和0.5的增量，切片厚度为1 mm, 200 mAs, 120 kV，剂量自动调节。IntelliSpacePortal 11被用来显示和评估软组织和骨骼结构图像。测量时，选择能清晰看到耳道垂直部分与鼓膜交界处，且能看到整个耳道水平部分的水平段的水平段。
The following CT features were recorded for each ear: • Maximum diameter of the porus acusticus externus; a detailed description of the measurement method is provided below (Figure 2). • Material/fluid in the tympanic bulla; if present, it was graded as mild, moderate or severe depending on the percentage of the bulla that was occupied (<30%, 30–60% or > 60%, respectively). • Material/fluid within the bony external ear canals was graded as normal, mild, moderate or severe depending on 0%, <30%, 30%–60% or > 60% filling of the ear canal diameter, respectively (Figure 3). 记录每耳以下CT特征:
•外耳道最大直径;测量方法的详细描述如下(图2)。
•鼓泡内的物质/液体;如果存在，则根据鼓泡所占比例分为轻度、中度或重度(分别为<30%、30-60%或> 60%)。
•根据骨性外耳道内的物质/液体占耳道直径比例0%、<30%、30% - 60%或> 60%，分为正常、轻度、中度或重度(图3)。
Measurement of the porus acusticus externus 外耳道孔径的测量 The porus acusticus externus was selected for the description and measurement of the auditory canal’s irregular course. A newly developed measurement technique was used to determine the maximum diameter of the left and right porus in millimetres (Figure 2). The cranial and caudal bony walls of the horizontal part of the ear canal were idealised with a straight line in the dorsal CT representation. At the outer edge of the cranial wall, a perpendicular line was measured to connect the two straight lines as an idealised maximum diameter of the porus acusticus externus. 选择外耳道孔径来描述和测量耳道的不规则发展。使用一种新开发的测量技术来确定左右孔的最大直径(以毫米为单位)(图2)。耳道水平部分的颅侧和尾侧骨壁在背侧CT表现中用一条直线理想化。在颅壁外边缘，测量一条垂直线连接两条直线，作为外耳道孔径的理想最大直径。
All CT measurements were compared to those obtained from the normocephalic group. 将所有CT测量值与头型正常组进行比较。
Statistical methods 统计方法 Statistical analysis was performed using PRISM (v7, GraphPad Software; La Jolla, CA, USA). The D‘Agostino–Pearson normality test was carried out to check if the values were normally distributed. For the normally distributed data, a one-way ANOVA was used after testing for equality of variance using Brown–Forsythe and Bartlett’s tests, followed by post hoc Bonferroni correction for the alpha error accumulation. The results are presented as mean ±standard deviation. For non-normally distributed data, the Kruskal–Wallis test was used before Dunn’s multiple comparisons test. The results are presented as median values with interquartile ranges (IQRs). Statistical significance was set at P<0.05. To investigate the relative risk of a characteristic with brachycephalic or normocephalic head shape, contingency tables were examined using Fisher’s exact test (two-sided, 95% confidence interval). The relative risk, odds ratio and sensitivity/specificity were investigated via the Koopmann Asymptotic Score, Baptista–Pike method and hybrid Wilson–Brown method, respectively. 使用PRISM。进行D Agostino Pearson正态性检验，检验值是否正态分布。对于正态分布数据，在使用Brown Forsythe和Bartlett s检验检验方差的平等后，使用单向方差分析，然后对alpha误差积累进行事后Bonferroni校正。结果以平均标准差表示。对于非正态分布的数据，先采用Kruskal Wallis检验，再采用Dunn多重比较检验。结果以四分位范围(iqr)的中值形式呈现。P＜0.05具有统计学意义。为了调查短头型或正常头型头部特征的相对风险，使用Fisher精确检验(双面，95%置信区间)检查列联表。通过Koopmann渐进评分法、Baptista Pike法和混合Wilson Brown法分别研究相对风险、优势比和敏感性/特异性。
Results 结果 A total of 75 brachycephalic dogs (20 pugs, 55 FB) were included in this prospective study. Of these, 54 were male (three of these neutered) and 21 were female. From our database, CT examinations of 37 nonbrachycephalic dogs were evaluated retrospectively. The breed distribution is listed on Table 1. They were examined radiologically for reasons other than ear diseases. The comparison of age, weight and diameter of the porus acusticus externus of pugs, FB and the control group is summarized on Table 2. The median diameter of the porus acusticus externus was 2.6 mm (IQR 2.3–2.9) in brachycephalic patients and 5 mm (4.5–5.5) in the control group (P < 0.0001). No significant difference in the right and left diameters was found in any group [right side: median 2.5 mm (IQR 2.2–2.8), left side: median 2.6 mm (IQR 2.3–2.9)] (Figure 4). 本前瞻性研究共纳入75只短头犬(20只巴哥犬，55只FB)。其中，54只雄性(其中3只已绝育)，21只雌性。从我们的数据库中，对37只非短头犬的CT检查进行了回顾性评估。品种分布见表1。由于耳病以外的原因对他们进行了放射检查。巴哥犬、FB组和对照组的年龄、体重和外耳道孔径的比较见表2。短头畸形组外耳道孔径中位数为2.6 mm (IQR 2.3-2.9)，对照组为5 mm (4.5-5.5) (P＜0.0001)。各组左、右直径均无明显差异[右侧中位2.5 mm (IQR 2.2-2.8)，左侧中位2.6 mm (IQR 2.3-2.9)](图4)。
Thirty-three of the 75 brachycephalic dogs (44%) had soft tissue isodense material in the tympanic cavity (20 unilateral, 13 bilateral). In total, 46 of 150 (30.7%) middle ears of pugs and FB were affected (Table 3). One dog in the control group had soft tissue/fluid material unilaterally in the tympanic cavity without any changes in the bulla wall and mild graduation. The dog was diagnosed with chronic idiopathic rhinitis (Figure 5). 75只短头犬中有33只(44%)鼓室软组织密度(20只单侧，13只双侧)。巴哥犬和FB的150只中耳中有46只(30.7%)患病(表3)。对照组的一只犬有单侧鼓室软组织/液体密度，鼓泡壁没有任何变化和轻度分级。犬被诊断患有慢性特发性鼻炎(图5)。
Soft tissue/fluid-attenuating material within the osseous external ear was detectable in 124 of 150 (82.6%) of the examined auditory canals of pugs and FB (Table 3). The finding was unilateral in 12 (17.6%) brachycephalic dogs and bilateral in 56 (82.4%). Only 14 of 74 (18.9%) dogs in the control group had soft tissue/fluid-attenuating material within the osseous external ear (mild, 10; moderate, one; severe, three). 巴哥犬和FB的150只外耳道中，有124只(82.6%)发现骨性外耳道内软组织/液体密度(表3)。12只(17.6%)短头犬单侧发现，56只(82.4%)双侧发现。对照组74只犬耳中只有14只(18.9%)在骨性外耳道内有软组织/液体密度(轻度：10只;中度：1只;重度：3只)。
In order to estimate the correlation between CT characteristics and otitis externa, all brachycephalic dogs were divided into OE and N-OE groups based on the owner questionnaire, and cytological and endoscopic findings. Overall, 53 of 75 (70.6%) owner questionnaires, 21 of 75 (27.9%) cytological examinations and 22 of 75 (29.3%) endoscopies were deemed suspicious for OE. A total 24 of 75 animals (32%) had at least two of three evaluation criteria and hence were included as the OE group. The remaining 51 of 75 dogs were included in the N-OE group. There was no significant difference in group allocation between the two brachycephalic breeds (OE-group, pugs 35%, FB 30,9%). 为了评估CT特征与外耳炎的相关性，根据宠主问卷、细胞学检查和内镜检查结果将所有短头犬分为OE组和N-OE组。总体而言，75例中有53例(70.6%)接受了问卷调查，75例中有21例(27.9%)接受了细胞学检查，75例中有22例(29.3%)接受了内窥镜检查。75例中有24例(32%)至少符合三项评价标准中的两项，因此被纳入OE组。75只犬中其余51只属于N-OE组。两种短头犬的组分配差异不显著(OE组，巴哥犬；35%，FB：30,9%)。
When considering the maximum diameter of the porus acusticus externus, there was no significant difference between the OE and N-OE groups. Furthermore, there was no correlation between OE/N-OE and soft tissue isodense material in the tympanic cavity. Of 46 tympanic cavities with soft tissue density detected, OE could be detected in 24, and no otitis was detected in 22. By contrast, we could detect material/fluid within the bony external ear canals significantly more frequently in animals with OE. Otitis externa was found in 47 of 124 obstructed auditory canals. 在考虑外耳道孔径最大直径时，OE组与N-OE组之间无显著差异。此外，OE/N-OE与鼓室软组织密度无相关性。检测到软组织密度的46个鼓室中，24个检出OE, 22个未检出耳炎。相比之下，我们可以在OE动物中更频繁地检测到骨性外耳道内的物质/液体。124个耳道㹴阻者中有47个发现外耳炎。
An important endoscopic examination result was that only five of 150 eardrums (3.3%) could be visualised otoscopically and were intact. In total, 145 tympanic membranes were not visible (Figure 1). 一个重要的内窥镜检查结果是150个鼓膜中只有5个(3.3%)可以通过内窥镜看到并且完好无损。共有145个鼓膜不可见(图1)。
Discussion 讨论 All brachycephalic animals showed a high degree of stenotic malformation of the proximal external auditory canal. On CT examination, stenosis of the porus acoustic externus with a reduction of the lumen to 50% of the normocephalic control group was found. However, no statistical difference between stenosis of the external auditory canal and OE was found.
所有短头动物均表现为外耳道近端高度狭窄畸形。CT检查发现外耳道近端狭窄，孔径缩小到正常头型对照组的50%。然而，外耳道狭窄与OE之间并无统计学差异。
In recent years, various studies have focused on breeding-induced malformations of the middle ear in brachycephalic dogs. Primarily, the conformation of the tympanic bulla and the content of the tympanic cavity have been investigated. However, there is almost no knowledge about the stenotic malformation of the external auditory canal in brachycephalic breeds, which is a common finding in everyday clinical practice. This stenosis complicates the treatment of OE and OM because it is difficult during otoscopic examination to visualise the tympanic membrane in brachycephalic dogs. To date, the cause of this narrowing is not known and, according to the results of our study, it could be due to malformation in the bony part of the acoustic meatus. 近年来，各种研究都集中短头犬品种畸形导致的中耳炎。本文主要对鼓泡形态和鼓室内容物进行了探讨。然而，关于短头犬外耳道狭窄畸形的认识几乎为零，这在日常临床中是常见的现象。这种狭窄使OE和OM的治疗复杂化，因为在耳镜检查中很难看到短头犬的鼓膜。到目前为止，这种狭窄的原因尚不清楚，根据我们的研究结果，它可能是由于骨性外耳道的畸形。
A possible cause of stenosis of the acoustic meatus in brachycephalic breeds is malformation of the entire skull with extreme shortening of the craniofacial bone structures, as well as the discrepancy between the viscerocranium and neurocranium. The porus acusticus externus and the middle ear are located in the pars petrosa of the temporal bone and are therefore affected by neurocranium malformation. This anatomical deviation is supported by results of a previous study that found a change in position and reduction in the size of the middle ear of FB. It is possible that these shifts also extend to the external auditory canal. To date, no studies have measured the bony structures in this area in brachycephalic dogs. Positive contrast ear canalography in dogs revealed stenosis, particularly in the proximal part of the cartilaginous auditory canal in pugs and Pekingese. In comparison to all other breeds that were examined, the tympanic membrane of these dogs could not be visualised by X-ray after contrast media had been placed in the ear canal, as the fluid could not penetrate to the tympanic membrane due to stenosis. 短头犬耳道狭窄的一个可能原因是整个颅骨畸形，颅面骨结构极度缩短，以及面颅和脑颅之间的差异。外耳道孔径和中耳位于颞骨岩部，因此受到脑颅畸形的影响。这一解剖学偏差得到了先前研究结果的支持，即发现FB的中耳位置改变和大小缩小。这些变化也有可能延伸到外耳道。迄今为止，还没有研究测量过短头犬这一区域的骨结构。犬耳道造影阳性显示狭窄，尤其是巴哥犬和京巴犬耳道软骨近端狭窄。与其他犬种相比，在耳道注入造影剂后，由于狭窄，液体无法流到鼓膜，x线无法看到鼓膜。
Classic primary causes of chronic OE are hypersensitivity disorders such as atopic dermatitis (AD) or abnormal anatomy of the auditory canal. Therefore, we hypothesised that, in brachycephalic dogs, anatomical narrowing may exacerbate pre-exisiting inflammatory processes in the external auditory canal such as AD. In this hypothesis, the bony stenosis leads to a lack of self-cleaning, an accumulation of secretions and hair, and, finally, to the onset of OE. Because the evaluation of co-morbidities was not part of this study, the primary or secondary role of stenosis in the onset of otitis could not be confirmed. However, it should be noted that the brachycephalic dogs in our study had a higher prevalence (32%) of OE than is generally reported for dogs (10–20%). 慢性OE的原发病因是过敏性疾病，如特应性皮炎(AD)或耳道解剖异常。因此，我们假设，在短头犬中，解剖学上的狭窄可能会加剧已存在的外耳道炎症过程，如AD。在这一假说中，骨结构狭窄导致自我清洁下降，分泌物和毛发的积累，最终导致OE的发生。由于评估并发病不在本研究的范围内，狭窄在耳炎发病中的原发或继发作用尚不能确定。然而，值得注意的是，在我们的研究中，短头犬的OE患病率(32%)高于一般报道的犬的患病率(10%-20%)。
In this study, the soft tissue structures in the acoustic meatus were not measured quantitatively; however, in 82.6% of dogs, soft tissue or fluid was identified in the lumen by CT. This correlated with the presence of OE and could therefore be both a consequence and cause of inflammation. Narrowing of the ear canal resulting from cartilage changes or an increase in soft tissue may play a role in the predisposition of brachycephalic breeds to OE. Previous CT examination of dogs with OM showed that FB was the most frequently affected breed at 15%, notably for proliferative otitis. This may be related to an increased rate of underlying hypersensitivity disorders or the special conformation of the ear or both. The high prevalence of soft tissue/fluid-attenuating material within the osseous external ear also was confirmed by the results of our endoscopic examinations, in which the view of the tympanic membrane was blocked by soft tissue in 96.7% of cases. Even in dogs without OE that had little or no secretion, it was impossible to view the tympanic membrane as a consequence of the extreme stenosis of the acoustic meatus. A general weakness of the cartilage, especially in the larynx of pugs, is described in the literature. This problem also is discussed as the cause of malfunction of the Eustachian tube. Pathohistological examinations should clarify whether this also applies to the cartilaginous part of the ear canal. 在本研究中，未对耳道内的软组织结构进行定量测量;然而，在82.6%的犬中，CT发现耳道内有软组织或液体。这与OE的存在相关，因此可能是炎症的结果和病因。软骨改变或软组织增加导致的耳道狭窄可能是短头犬易患OE的原因之一。以前对OM犬的CT检查显示FB是最常患病品种，占15%，特别是增生性耳炎。这可能与潜在过敏性疾病或耳部特殊构象或两者的发病率增加有关。我们的内镜检查结果也证实了骨性外耳道内软组织/液体密度的高患病率，其中96.7%的病例鼓膜的视野被软组织阻塞。即使是少量或没有分泌物的未患OE的犬，由于耳道极度狭窄也不可能看到鼓膜。在文献中描述，软骨普遍发育不良，特别是在巴哥犬的喉部。此问题也被认为是引起咽鼓管功能障碍的原因。应通过病理组织学检查明确这是否也适用于耳道的软骨部分。
In this study, 33 of 75 (44%) brachycephalic dogs had soft tissue isodense material in the tympanic cavity. A previous study found a similar prevalence (36%) of tympanic effusion in asymptomatic dogs that needed to undergo brachycephalic surgery. It was striking that pugs and bulldogs without OE had tympanic effusion similar to dogs with OE. This allows us to draw conclusions about the origin of the change. Generally, the transmission of OE to the middle ear is the most common cause of OM in dogs. However, this does not seem to be the case in this study. We did not perform myringotomy and cytological and cultural analysis of the middle ear contents, and therefore the origin of the effusion cannot be known for certain. The content of the tympanic bulla in brachycephalic dogs appears to be noninflammatory, which supports the theory of a drainage disorder. 在本研究中，75只短头犬中有33只(44%)在鼓室中有软组织密度。之前的一项研究发现，在需要接受短头畸形手术的无症状犬中，鼓室积液的发生率相似(36%)。令人惊讶的是，没有OE的巴哥犬和斗牛犬与患有OE的犬有相似的鼓室积液。这使我们能够对变化的起源作出结论。一般来说，OE发展到中耳是导致犬OM最常见的病因。然而，在这项研究中，情况似乎并非如此。我们没有进行鼓膜切开术，也没有对中耳内容物进行细胞学检查和培养分析，因此无法确定积液的来源。短头犬鼓泡内容物似乎是无炎症的，这支持了引流障碍的理论。
It is believed that dysfunction of the auditory tube in brachycephalic dogs could play a role here. The dogs in our study showed no clinical signs and no further evidence of OM such as lysis of the bulla wall on CT. 认为短头犬的咽鼓管功能障碍可能与此有关。在我们的研究中，犬没有临床症状，也没有进一步的证据显示OM，如鼓泡壁溶解。
We note two limitations in this study. First, the owner questionnaire (Appendix S1) used to assess the symptoms of OE is a subjective assessment and owner’s may have misinterpreted signs of otitis. Our criteria, namely cytology and endoscopy are more objective measurements. 我们注意到本研究的两个局限性。首先，用于评估OE症状的宠主问卷(附录S1)是一种主观评估，宠主可能误解了耳炎的症状。我们的标准，即细胞学检查和内窥镜是更客观的测量。
Secondly, the dogs presented for brachycephalic surgery were a preselected patient population and this could have biased the study participants. 其次，接受短头畸形手术的犬是一个预先选定的患者群体，这可能会使研究参与者产生偏见。
Conclusions 结论 The high-grade stenosis of the acoustic meatus in brachycephalic dog breeds, particularly the bony porus acusticus externus and the tympanic bulla, is evidence that the ear is an organ which is extremely disturbed in form and function by selective breeding practices. However, a connection between stenosis of the external auditory canal and OE could not be confirmed. The results of this clinical study reiterate that the extent of congenital brachycephalic malformation and functional disorders go far beyond malformations of the upper respiratory tract.
短头犬品种的耳道高度狭窄，特别是外耳道孔径和鼓泡，这证明了耳部是一个在形式和功能上被选择性育种严重干扰的器官。然而，外耳道狭窄与OE之间的联系尚未得到证实。本临床研究的结果再次表明，先天性短头畸形和功能障碍的范围远远超出上呼吸道畸形。 Figure 1. Otoscopic examination of the horizontal part of the external auditory canal in two French bulldogs (a, b). The ear canals show no signs of inflammation or secretions. The eardrum cannot be visualised otoscopically due to stenosis. 图1。耳镜检查2只法国斗牛犬的外耳道水平部分(a, b)。耳道无炎症或分泌物症状。由于耳道狭窄，耳镜无法看到鼓膜。 Figure 2. Measuring the diameter of the porus acusticus externus. The external auditory canal of a French bulldog is shown (dorsal cross-section) by computed tomography. The cranial (a) and caudal (b) bony wall of the horizontal part of the auditory canal was idealised with a straight line. Both lines are connected at right angles to each other at the outer bony margin. The distance between the two straight lines (x) is measured as the diameter of the porus acusticus externus. 图2。测量外耳道孔径。计算机断层扫描显示法国斗牛犬的外耳道(背侧横截面)。外耳道水平部分的颅侧(a)和尾侧(b)骨壁用一条直线理想化。两条线在外侧骨边缘以直角相互连接。两条直线之间的距离(x)测量为外耳道孔径。 Figure 3. Skull of a French bulldog shown in a dorsal cross-section from computed tomography (2,500/-300). The lumen of the bony part of the horizontal auditory canal is blocked by soft tissue and/or fluid (red arrow). 图3。计算机断层扫描显示的一只法国斗牛犬的背侧横截面颅骨(2500 /-300)。水平耳道骨性部分的管腔被软组织和/或液体阻塞(红色箭头)。
Table 1. Breed distribution of the dogs in the control group (n = 37) 表1。对照组犬品种(n = 37) Table 2. Median values (with interquartile range) for age, body weight and diameter of the porus acusticus externus of pugs, French bulldogs (FB) and control group. 表2。巴哥犬、法国斗牛犬(FB)和对照组的年龄、体重和外耳道孔径的中位数(四分位数范围)。 Figure 4. Diameter of the porus acusticus externus in mm determined using computed tomography for pugs (n = 20), French bulldogs (FB, n = 55) and normocephalic control dogs (N-CD, n = 37). Results are displayed as a box plot (interquartile range, median, minima, maxima); ****, P < 0.0001 (Kruskal–Wallis test). 图4。使用计算机断层扫描测定巴哥犬(n = 20)、法国斗牛犬(FB, n = 55)和正常头型对照犬(n - cd, n = 37)的外耳道孔径(mm)。结果显示为箱形图(四分位范围、中位数、最小值、最大值);****， P < 0.0001 (Kruskal-Wallis检验)。
Figure 5. The number of ears with otitis media (OM), defined as tympanic cavity effusion on computed tomography in brachycephalic (B-CD, 46 of 150) and normocephalic (N-CD, one of 74) dogs. The correlation between brachycephaly and middle ear effusion was highly statistically significant when compared to normocephaly and middle ear effusion using Fisher’s exact test; ****, P < 0.0001. 图5。中耳炎(OM)在短头型(B-CD, 46/150)和正常头型(N-CD, 1/74)犬的计算机断层扫描中定义为鼓室积液的耳数。采用Fisher精确检验，短头犬和中耳积液与正常头型和中耳积液之间的相关性具有高度统计学意义;****， p < 0.0001。
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发表于 2022-6-8 22:15:25
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