猫外侧鼓泡截骨术的术后形态学特征

王帆

Morphological aspects of tympanic bulla after lateral osteotomy in cats

猫外侧鼓泡截骨术的术后形态学特征

作者：Adelina Maria da Silva , Wilson Machado de Souza, Roberto Gameiro de Carvalho, Gisele Fabrino Machado , Silvia Helena Venturoli Perri

 

翻译：王帆

 

ABSTRACT

Purpose: To evaluate tympanic bulla healing after experimental lateral osteotomy in cats. Methods: Twenty adult cats were submitted to unilateral lateral bulla osteotomy and divided into two groups: cats of B1 group (n=10) were euthanized at 8 weeks and cats of B2 group (n=10), at 16 weeks postoperative. Results: Oblique lateral radiographs taken immediately postoperative showed interruption in the contour of the external acoustic meatus of the operated bullae in all cats of both groups (McNemar test: p=0.0010*). This feature was still observed in the radiographs taken after 8 and 16 weeks postoperative (McNemar test: B1 p=0.0020*; B2 p=0.0312*). Macroscopic examination showed that the operated bullae were similar to the normal ones, with preservation of the tympanic cavity. Connective tissue at the osteotomy site was significantly found in the operated bullae in both groups (McNemar test: B1 p=0.0020*; B2 p=0.0010*). The length of connective tissue at the osteotomy site was measured by histomorphometry. There was no statistically significant difference between the values of B1 group and B2 group (Mann-Whitney test: p=0.0524). Conclusions: Experimental lateral osteotomy did not alter significantly the tympanic bulla conformation and complete regeneration of the tympanic bulla frequently did not occur before 16 weeks of postoperative period. Key words: Ear, middle. Ear neoplasms. Cats.

摘要

目的:观察猫实验性外侧截骨术后鼓泡愈合情况。方法:将20只成年猫行单侧外侧鼓泡截骨术，分为两组:B1组(n=10)于术后8周安乐死，B2组(n=10)于术后16周安乐死。结果:术后立即拍斜侧位x光片显示，两组所有猫的手术鼓泡外耳道轮廓均出现中断(McNemar检验:p=0.0010*)。术后8周和16周的x光片仍然观察到这一特征(McNemar检验:B1 p=0.0020*;B2 p = 0.0312 )。肉眼检查显示，手术鼓泡与正常鼓泡相似，鼓室保存完好。两组手术鼓泡截骨部位均可见结缔组织(McNemar检验:B1 p=0.0020;B2 p = 0.0010 *)。用组织形态术测量截骨部位结缔组织的长度。B1组与B2组比较差异无统计学意义(Mann-Whitney检验:p=0.0524)。结论:实验性外侧截骨术对鼓泡形态无明显改变，术后16周前鼓泡未发生完全再生。关键词:耳部、中耳、耳肿瘤、猫

 

Introduction

介绍

Total ear canal ablation with lateral tympanic bulla osteotomy (TECA/LBO) is most frequently indicated for cats with neoplastic disease of the ear.  The most common ear tumors in these animals are ceruminous gland adenocarcinoma and squamous cell carcinoma. The tympanic bulla in cats is divided into a dorsolateral and a ventromedial compartment by an incomplete septum in the caudomedial aspect of the smaller compartment that allows communication between the cavities. Thus, when lateral bulla osteotomy is performed, part of this septum must be removed for proper curettage and drainage of both compartments, and the surgeon has to avoid injuries to the structures of hearing and balance or to the nerve tracts that cross the middle ear.

全耳道消融加外侧鼓泡截骨术(TECA/LBO)最常用于猫耳肿瘤性疾病。在这些动物中最常见的耳肿瘤是耵聍腺腺癌和鳞状细胞癌。猫的鼓泡被一个在尾内侧有小孔的不完整的鼓室中隔，分为背外侧和腹内侧两个腔室。因此，当进行外侧鼓泡截骨术时，必须切除部分鼓室中隔，进行适当的刮除和引流，术者必须避免损伤听力和平衡结构或横过中耳的神经束。

 

A better understanding of the consequences of TECA/LBO may improve the management of recurrences, reoperations and changes in middle-ear function, since this procedure is increasingly common in cats. In spite of this, we have not found experimental studies about this surgery in cats. In fact, healing of tympanic bulla after TECA/LBO has been evaluated mostly in dogs, whose bulla consists of a single compartment.Therefore, this study evaluates the morphology of the tympanic bulla after TECA/LBO in cats by radiographic, macroscopic, histopathological and histomorphometric examinations. Risks of nerve and inner ear damage were also assessed.

更好地理解TECA/LBO的后果可以改善对复发、再手术和中耳功能变化的管理，因为这一过程在猫中越来越常见。尽管如此，我们还没有在猫上发现关于这种手术的实验研究。事实上，鼓泡在TECA/LBO后的愈合大多在犬上进行评估，犬的鼓泡只有一个腔室。因此，本研究通过x线、肉眼评估、组织病理学和组织形态学检查评价猫TECA/LBO后鼓泡的形态。神经和内耳损伤的风险也进行了评估。

 

Methods

方法

This study was approved by the Ethics Committee for Animal Research of the São Paulo State University – campus Araçatuba.
这项研究得到了São保罗州立大学动物研究伦理委员会的批准。

 

Animals and experimental design

动物与实验设计

Twenty healthy young adult (aging between 8 and 24 months) mixed breed cats (weighing 3,0 ± 0,4kg) were utilized. Ten spayed females and 10 neutered males were used. Experimental total ear canal ablation with lateral tympanic bulla osteotomy (Figure 1) was performed at random in either the right or left ear. Animals were divided into two groups, according to the postoperative observation time: cats of B1 group (n=10) were euthanized at 8 weeks and cats of B2 group (n=10), at 16 weeks postoperative.
实验采用20只健康的年轻成年(年龄在8到24个月之间)杂交猫(体重为3.0±0.4 kg)。使用了10只已绝育雌性和10只已去势雄性。随机在右耳或左耳进行实验性全耳道消融和外侧鼓泡截骨术(图1)。根据术后观察时间将动物分为两组:B1组(n=10)于术后8周安乐死，B2组(n=10)于术后16周安乐死。

 

Surgical procedure

手术过程

Food was withheld for 12 hours prior to anesthesia. The cats were premedicated with atropine (0.05mg/kg SC) and xylazine (2mg/kg SC). Anesthesia was induced with ketamine (15mg/kg, SC), and maintained with thiopental (5mg/kg IV) and fentanil (0.0125mg/kg IM). Lactated Ringer’s solution (10ml/kg IV) was administered throughout anesthesia. Enrofloxacin (5mg/kg SC) and ketoprofen (2mg/ kg SC) were administered preoperatively and for 3 days postoperatively.

麻醉前禁食12小时。预先给猫注射阿托品(0.05mg/kg SC)和赛拉嗪(2mg/kg SC)。以氯胺酮(15mg/kg, SC)诱导麻醉，以硫喷妥钠(5mg/kg IV)和芬太尼(0.0125mg/kg IM)维持麻醉。整个麻醉过程中均给予乳酸林格氏液(10ml/kg IV)。术前和术后3天分别给予恩诺沙星(5mg/kg SC)和酮洛芬(2mg/ kg SC)。

 

The lateral cranial and cervical regions were clipped, prepared, and draped under sterile technique. Cats were positioned in lateral recumbency. A T-shaped skin incision was made over the vertical ear canal, encircling the external ear canal opening. Using blunt and sharp dissection, the cartilage of the vertical ear canal was dissected from the overlying skin and surrounding soft tissue. Upon reaching the osseous external acoustic meatus, the cartilaginous ear canal was transected with scissors. A rongeur was used to remove the ventral rim of the osseous external acoustic meatus and a portion of the lateral wall of the tympanic bulla (circa 8mm x 5mm). Removal of the tympanic membrane and malleus was attempted with a curved mosquito hemostat. The septum of the bulla was opened with a curette. The epithelium and lamina propria lining the osseous external acoustic meatus was removed with an electric driven burr. The tympanic cavities of the two compartments were curetted and irrigated with 0.9% saline. A 1-cm diameter Penrose drain was placed at the edge of the tympanic cavity, exited through a separate stab incision in the skin ventrally to the surgical wound. Subcutaneous layer was closed with 4-0 polyglactin 910. Skin closure was with 4-0 nylon. The Penrose drain was removed after 3 days and skin sutures removed on day 7.

颅侧和颈部区域在无菌技术下剃毛、备皮和覆盖。猫取侧卧位。在垂直耳道上做一个T型皮肤切口，环绕外耳道开口。采用钝性和锐性分离方法，将垂直耳道的软骨从上面的皮肤和周围软组织中分离出来。到达骨性外耳道后，用剪刀剪断软骨耳道。用咬骨钳切除骨性外耳道腹侧缘和鼓泡外侧壁的一部分(约8mm × 5mm)。用弯曲的蚊式钳取出鼓膜和锤骨。用刮匙打开鼓泡的鼓室中隔。用电驱动磨钻去除骨性外耳道内的上皮和固有层。刮除两个腔室，用0.9%生理盐水冲洗。在鼓室边缘放置直径1厘米的Penrose引流管，通过皮肤腹侧的进行单独切口引流出。皮下用4-0聚glactin 910缝合。皮肤闭合用4-0尼龙。3天后取出Penrose引流管，第7天取出皮肤缝合线。

 

Postoperative observations and radiographs

术后观察和x光片

After bulla osteotomy the cats were monitored for clinical signs of Horner’s syndrome, damage to the inner ear and facial nerve paralysis.

在鼓泡截骨术后，观察猫是否出现霍纳氏综合征、内耳损伤和面神经麻痹的临床症状。

 

Radiographs were performed immediately after surgery and at the end of the study, i.e., after 8 (B1) and 16 (B2) weeks postoperative. Oblique lateral, ventrodorsal, and open-mouth views of the tympanic bullae were taken.

在术后立即和研究结束时，即术后8 (B1)和16 (B2)周后进行x光片检查。分别拍鼓泡斜侧位、腹背位和张口位。

 

Macroscopic analysis, histolopathology and histomorphometry

肉眼评估、组织病理和组织形态测量学

The cats were euthanized with thiopental (45mg/ kg IV) after 8 (B1 group) and 16 weeks (B2 group) postoperative. The normal and operated tympanic bullae of each cat obtained at necropsy were fixed in 10% formalin and decalcified in an aqueous solution of 5.66 formalin 10% to 1 of nitric acid (v/v). Then, each of these bullae was divided into two segments longitudinal to the larger axis of the osteotomy. The specimens were processed routinely and thin sections were made and stained with hematoxylin-eosin for microscopic evaluation.

术后8周(B1组)和16周(B2组)分别给予硫喷妥钠(45mg/ kg IV)安乐死。取每只猫的正常侧和手术侧鼓泡在10%福尔马林固定，并在5.66福尔马林10%到1硝酸(v/v)的水溶液中脱钙。然后，每个鼓泡沿纵向截骨大轴分为两部分。常规处理标本，制作薄切片，用苏木精-伊红染色进行显微镜评价。

 

For the histomorphometry, the images of sections were captured using a Leica DMLS microscope connected to a Sony Power HAD 3 CCD video camera, and transferred to an image analyzer (Leica QWIN). In this planimetric study, the connective tissue length at the osteotomy site was measured in µm. The largest value obtained from each cat was included in data analysis.

对于组织形态测量，使用连接到索尼Power HAD 3 CCD摄像机的徕卡DMLS显微镜捕获切片图像，并传输到图像分析仪(徕卡QWIN)。在这项平面测量研究中，截骨部位的结缔组织长度以µm为单位进行测量。从每只猫上获得的最大值被纳入数据分析。

 

Statistical analysis

统计学分析

Non-parametric tests were utilized for the data analysis, taking into consideration the nature of the variables. McNemar’s test was used to compare data between operated bullae and contralateral unoperated bullae. Mann-Whitney’s test was used to compare histomorphometric data between groups B1 and B2. Significance was set at p≤0.05.

考虑到变量的性质，采用非参数检验进行数据分析。采用McNemar检验比较手术鼓泡与对侧未手术鼓泡的资料。Mann-Whitney检验用于比较B1组和B2组之间的组织形态学数据。显著性设置为p≤0.05。

 

Results

结果

None of the operated cats showed clinical signs of either Horner’s syndrome or damage to the inner ear. Clinical signs of facial nerve damage were observed in 6 cats. There was one case of facial neuropraxia in one cat from B1 group. The neurological deficit of this animal was resolved by 32 days postoperative. Facial paralysis occurred in 2 cats from B1 group, which remained with a wide palpebral fissure. Postoperative facial neuropraxia was observed in 3 cats from B2 group, but the signs resolved within 25, 27 and 60 days, respectively, for each animal.

所有接受手术的猫都没有表现出霍纳氏综合征或内耳损伤的临床症状。观察了6只猫面神经损伤的临床症状。B1组1只猫出现面神经损伤。术后32天神经损伤得到解决。B1组2只猫出现面瘫，但仍有较宽的睑裂。B2组3只猫术后出现面神经损伤，但症状分别在25、27和60天内消退。

 

Oblique lateral radiographs performed immediately postoperative showed an interruption in the contour of the osseous external acoustic meatus of the operated bulla in all cats of both groups (Figure 2; McNemar’s test p=0.0010*) . This feature was still observed in 9 cats from B1 group (p=0.0020*) and in 5 cats from B2 group (p=0.0312*) in the radiographs taken after 8 (Figure 3) and 16 weeks postoperative, respectively.

术后立即进行的斜侧位x光片显示，两组所有猫的手术鼓泡骨性外耳道的轮廓出现中断(图2;McNemar’s 检验p=0.0010*)。在术后8周(图3)和16周的x光片中，B1组的9只猫(p=0.0020*)和B2组的5只猫(p=0.0312*)仍然观察到这一特征。

 

The macroscopic examination revealed that the operated tympanic bullae were similar to the normal ones, with preservation of the tympanic cavity, in both B1 and B2 groups (Figure 4). In group B1, 3 operated bullae presented a slight protuberance in the inner surface of the larger compartment. Also in group B1 the orifice made in the bone septum was still open in one cat, the malleus was still present in 7 tympanic bullae and accumulation of secretion near the external acoustic meatus was observed in 2 cats. In B2 cats the slight protuberance in the inner surface of the larger compartment was present in 3 tympanic bullae. The bone septum was thicker in one cat. The malleus was still present in 4 tympanic bullae. Accumulation of secretion near the external acoustic meatus was observed in 7 cats.

肉眼检查显示，B1组和B2组手术后的鼓泡与正常鼓泡相似，鼓室完整保留(图4)。B1组3个手术后的鼓泡在大腔室内表面有轻微突起。同样在B1组中，1只猫的鼓室中隔孔仍然开放，7只猫的鼓泡中仍有锤骨存在，2只猫的外耳道附近有分泌物积累。B2猫的3个鼓泡内表面有轻微的突起。其中一只猫的鼓室中隔较厚。4个鼓泡内仍有锤骨存在。7只猫在外耳道附近观察到分泌物堆积。

 

Connective tissue was detected in 9 and 10 operated bullae, from groups B1 and B2, respectively (Figure 5), and only one cat from B1 group showed complete regeneration of the larger compartment after lateral osteotomy. The result of McNemar’s test was significant for both groups B1 (p=0.0020*) and B2 (p=0.0010*).

分别在B1组和B2组的9个和10个手术鼓泡中检测到结缔组织(图5)，只有B1组的一只猫在外侧截骨后显示大腔室完全再生。McNemar 's检验结果对B1组(p=0.0020*)和B2组(p=0.0010*)均有显著意义。

 

In group B1, the operated tympanic bullae showed a thickened osseous wall in most of the histological sections; thickening of the bone septum also occurred. Ceruminous gland adenitis as well as foci of neutrophils, neovascularization and foamy macrophages in the areas of mononuclear infiltration were observed in the histological sections of one cat of B1 group. The operated tympanic bullae of the B2 group also showed a thickened osseous wall in most of the histological sections. Thickening of the bone septum was also observed. Sebaceous glands, most of them hypertrophied, were found in the histological sections of 6 cats of this group. In many sections the connective tissue was covered by a stratified keratinized squamous epithelium. Histological analysis revealed that the smaller compartment was lined with ciliated pseudostratified columnar epithelium with numerous goblet cells. Three cats from group B2 showed inflammatory processes. Intense infiltration of neutrophils and macrophages with connective tissue proliferation in the lamina propria was found in one cat. Mononuclear infiltrations in the lamina propria and purulent exudate covering the epithelial surface of the tympanic cavity was observed in another cat from B2 group. Severe suppurative inflammation in the osteotomy area filled with connective tissue occurred in the operated tympanic bulla of a third cat from this group. The length of connective tissue at the osteotomy site was measured by the histomorphometry. There was no statistically significant difference between the values for groups B1 and B2 (Mann-Whitney’s test, p=0.0524; Table 1) .

B1组，手术侧鼓泡大部分组织学切片显示骨壁增厚;鼓室中隔增厚也发生。B1组1只猫的组织学切片上可见耵聍腺腺炎，单核浸润区可见中性粒细胞灶、新生血管和泡沫状巨噬细胞。B2组的手术鼓泡在大部分组织学切片上也显示骨壁增厚。还观察到鼓室中隔增厚。该组6只猫的组织学切片显示皮脂腺多为肥厚性皮脂腺。许多切片结缔组织被层状角化鳞状上皮所覆盖。组织学分析显示，小腔室排列有纤毛假分层柱状上皮，有大量杯状细胞。B2组的三只猫出现炎症过程。在一只猫的固有层中发现中性粒细胞和巨噬细胞的强烈浸润和结缔组织增生。B2组另一只猫在固有层可见单核浸润，鼓室上皮表面可见化脓性渗出物。该组第三只猫的手术鼓泡发生了充满结缔组织的截骨区严重化脓性炎症。用组织形态术测量截骨部位结缔组织的长度。B1组和B2组间差异无统计学意义(Mann-Whitney检验，p=0.0524;表1)。

 

Discussion

讨论

Retrospective clinical reports cal reports have indicated a prevalence of 12 to 26% of Horner’s syndrome after TECA/LBO. Horner’s syndrome, classically presenting with miosis, prolapse of the third eyelid and ptosis of the eyelid, is a result of direct damage to the postganglionic sympathetic fibers coursing to the eyes and eyelids where they pass through the tympanic cavity. No cats in our study showed clinical signs of Horner’s syndrome, possibly because during surgery the inner septum was carefully perforated but not removed.

回顾性临床报告显示，TECA/LBO后霍纳氏综合征的患病率为12% - 26%。霍纳氏综合征，典型表现为缩小，第三眼睑脱垂和眼睑下垂，是神经节后交感神经纤维直接损伤的结果，这些纤维通过鼓室到达眼睛和眼睑。在我们的研究中，没有猫表现出霍纳氏综合征的临床症状，可能是因为在手术中，小心地对鼓室中隔打孔，但没有移除。

 

Clinical signs (nystagmus, ataxia and head tilt) indicative of damage to inner ear structures were not observed in any of the 20 cats studied, probably because curettage of the promontory was avoided. Retrospective clinical reports of lateral bulla osteotomy have not made mention of the prevalence of inner ear damage.

在研究的20只猫中，没有观察到任何表明内耳结构损伤的临床症状(眼球震颤、共济失调和头倾斜)，可能是因为避免了对隆突刮除。回顾性的临床报告中，外侧鼓泡截骨术并没有提及内耳损伤的发生率。

 

The facial nerve was easily identified coursing along the caudolateral surface of the cartilaginous external acoustic meatus. It was stretched during dissection and facial nerve damage was observed in 6 cats. The clinical signs observed were lack of palpebral reflex and wide palpebral fissure. Drooping of the lip is a clinical sign cited by the literature but it was not observed in our experiment. In the clinical report of 15 cats submitted to TECA/LBO, Williams and White1 verified 4 cases of facial neuropraxia and 7 cases of facial paralysis. In this group, 11 cats had ear neoplastic disease, 3 had polyps and one showed chronic middle ear otitis.

面神经沿着外耳道软骨的尾外侧表面很容易识别。6只猫在分离过程中被拉伸，观察到面神经损伤。临床表现为睑反射缺失、睑裂宽。唇下垂是文献中引用的一个临床症状，但在我们的实验中没有观察到。在提交给TECA/LBO的15只猫的临床报告中，Williams和White1证实了4例面神经损伤和7例面瘫。在这组猫中，11只有耳肿瘤疾病，3只有息肉，1只有慢性中耳炎。

 

No abnormalities were found in the ventrodorsal radiographs of operated and normal bullae in the immediate postoperative period and at the end of the study in each group (B1 and B2). These abnormalities were probably masked by the overlap of cranial bones as described in a previous report on dogs submitted to experimental unilateral TECA/LBO. On the other hand, the open-mouth and oblique lateral radiographs afforded better visualization of the tympanic bulla, detached from the other cranial bones. This allowed the detection of some features in these projections. In all 20 cats from groups B1 and B2, the lateral osteotomy could be consistently detected through the interruption in the contour of the osseous external acoustic meatus in the oblique lateral radiographs taken immediately after surgery. Eight and 16 weeks after the lateral osteotomy, this interruption could still be seen on the radiographs of 9 cats from group B1 and 5 from group B2. Similar results were found in dogs submitted to experimental TECA/LBO. Bulla radiography is often useful in evaluating middle-ear disease. Radiographic evidence of bulla disease includes opacities in the tympanic cavity and thickening of the bulla wall. In the present study, increased density of the tympanic cavity was not found in any of the radiographs performed 8 (B1group) or 16 (B2 group) weeks after lateral osteotomy, indicating that the operated bulla remained filled with air and did not contain tissues or secretions. Thickening of the wall of the bulla was not observed either. A previous report in dogs found similar results.

各组(B1和B2)在术后即刻和研究结束时，手术侧鼓泡和正常侧鼓泡的腹背侧x线片均未发现异常。这些异常可能被先前提交给实验性单侧TECA/LBO的犬的报告中描述的颅骨重叠所掩盖。另一方面，开口位和斜侧位片能更好地显示避开颅骨的鼓泡。这使得能观察到这些影像位的一些特征。在B1组和B2组的所有20只猫中，通过术后立即拍摄的斜侧位片中，外侧截骨术后可一致观察到骨性外耳道轮廓的中断。外侧截骨术后8周和16周，在B1组的9只猫和B2组的5只猫的x光片上仍然可以看到这种中断。在接受TECA/LBO实验的犬上也发现了类似的结果。鼓泡x线片在评估中耳疾病时通常是有用的。鼓泡疾病的x线表现包括鼓室混浊和鼓泡壁增厚。在本研究中，在外侧截骨术后8周(b1组)或16周(B2组)的x线片中均未发现鼓室密度增加，表明手术鼓泡仍充满空气，不含组织或分泌物。鼓泡壁也未见增厚。此前一份关于犬的报告也发现了相似结果。

 

The macroscopic examination revealed that the concavity of the operated bullae was similar to the normal ones, with preservation of the tympanic cavity. Only a slight protuberance in the inner surface of the larger compartment was verified in 6 operated bullae. This disagrees with the results of a previous experimental study in dogs, in which the entire lateral wall of the tympanic bulla was removed. These authors observed that partial or complete obliteration of the tympanic cavity occurred in most of the dogs due to connective tissue and bone proliferation. In another experimental study in dogs, the bulla osteotomy was restricted to a small area of the lateral wall and the tympanic cavity was preserved almost at its normal volume. The bone septum orifice was closed in most of the tympanic bullae of both B1 and B2 groups. However, the communication between the two compartments of the middle ear, naturally present in the caudomedial aspect of the smaller compartment, near the coclear window, was not affected by the osseous proliferation because this occurred only at the osteotomy site in both groups.

肉眼检查显示，手术鼓泡的凹陷度与正常鼓泡相似，鼓室保存完好。在6个手术鼓泡中，只在大腔室的内表面发现了轻微的突起。这与之前一项犬的实验研究结果不一致，在该实验中，鼓泡的整个外侧壁都被切除了。这些作者观察到，由于结缔组织和骨增生，大部分犬的鼓室发生部分或完全闭塞。在另一项犬的实验研究中，鼓泡截骨术被限制在外侧壁的一小块区域，鼓室几乎保持正常体积。B1组和B2组鼓泡大部分鼓室中隔孔闭合。然而，中耳两个腔室之间的交流，自然通过小腔室尾内侧，靠近耳蜗窗，此处没有受到骨增生的影响，因为骨增生只发生在两组的截骨部位。

 

Removal of the tympanic membrane and malleus was attempted with a curved mosquito hemostat, but as shown in the macroscopic examination, this procedure was not always successful since the malleus was still present in 11 of the 20 tympanic bullae submitted to lateral osteotomy. No great effort was made to grasp the malleus because this maneuver could push the auditory ossicles against the vestibular window, and consequently cause inner ear damage. Regeneration of the tympanic membrane was not observed in any of the 20 cats. In a experimental study, retention of the tympanic membrane was observed in 2 of 12 dogs submitted to TECA/LBO. Removal of the tympanic membrane and malleus was attempted in our study so that the epithelium and lamina propria lining the external acoustic meatus could be thoroughly removed. Nevertheless this goal was not totally attained, because the presence of secretion was verified in 9 of the 20 tympanic bullae submitted to lateral osteotomy. As the epithelium and lamina propria lining the external acoustic meatus were not entirely removed with the electric-driven burr, remnants of sebaceous glands developed postoperatively and secretions of these glands accumulated at the surgical site. That indicates that the curettage of the external acoustic meatus must be carefully done. The performance of this procedure under magnification with a loupe or operating microscope could obtain better results.

我们尝试用弯曲的蚊式钳切除鼓膜和锤骨，但如肉眼检查所示，这一过程并不总是成功的，因为在20个鼓泡中，有11个接受外侧截骨术的鼓泡中仍然存在锤骨。因为这个动作可能会把听小骨推到前庭窗，从而造成内耳损伤，所以不需要花大力气抓住锤骨。20只猫中没有观察到鼓膜再生。在一项实验研究中，12只接受TECA/LBO的犬中有2只被观察到鼓膜滞留。在我们的研究中，我们尝试切除鼓膜和锤骨，以便能够彻底切除外耳道的上皮细胞和固有层。然而，这一目标并没有完全达到，因为20个鼓泡中有9个被证实有分泌物存在。由于电驱动磨钻没有完全清除外耳道的上皮细胞和固有层，术后皮脂腺残余形成，这些腺体的分泌物在手术部位堆积。这表明刮除外耳道必须小心进行。在放大镜或操作显微镜下，可获得较好的结果。

 

The histological examination revealed that only one cat from group B1 showed a tympanic bulla similar to the normal one. In the other 19 cats, connective tissue was observed at the osteotomy site. The operated tympanic bullae of both groups showed a thickened osseous wall and inner septum. Sebaceous glands were found in the histological sections of 6 cats of group B2. Sections of one cat from group B1 and of 3 cats from group B2 presented inflammatory process. There was a trend for the connective tissue length at the osteotomy site to be longer in group B2 than in group B1. The lateral bulla osteotomy was initiated in the ventral rim of the osseous external acoustic meatus. The connective tissue filled the osteotomy area and advanced in a proximal direction, since in this region there was no demarcation by osseous tissue. Furthermore there was an empty space left by the total ear canal ablation.

组织学检查显示，B1组只有一只猫的鼓泡与正常的鼓泡相似。在其他19只猫中，在截骨部位观察到结缔组织。两组手术鼓泡均表现为骨壁增厚和鼓室中隔增厚。B2组6只猫在组织学切片上发现皮脂腺。B1组1只猫和B2组3只猫的切片出现炎症过程。B2组截骨部位结缔组织长度有比B1组长的趋势。外侧鼓泡截骨术始于骨性外耳道腹侧缘。结缔组织填充了截骨区，并向近端方向推进，因为在该区域没有骨组织划分。此外，全耳道消融后还留下了一个空腔。

 

As a concluding remark, lateral osteotomy did not alter the tympanic bulla conformation and complete regeneration of tympanic bulla frequently did not occur before 16 weeks of postoperative period.

综上所述，外侧截骨术并没有改变鼓泡的形态，而且在术后16周之前鼓泡通常没有完全再生。

 

 

FIGURE 1 - Photograph of a feline skull, showing the margins of the lateral tympanic bulla osteotomy (outlined by dashed line). Observe the malleus (arrow).

图1 -猫颅骨照片，显示外侧鼓泡截骨边缘(虚线勾勒)。可见锤骨(箭头所指)。

 

FIGURE 2 — Radiograph in oblique lateral projection of cat 27 from group B2 immediately postoperative. Observe the interruption in the contour of the external acoustic meatus of the operated tympanic bulla (arrow).

图2 -术后B2组27号斜侧位的x光片。观察手术鼓泡外耳道轮廓的中断(箭头)。

 

 

FIGURE 3 — Radiograph in oblique lateral projection of cat 26 from group B1 taken 8 weeks postoperative. Observe the interruption in the contour of the external acoustic meatus of the operated tympanic bulla (arrow).

图3 -术后8周B1组26只猫斜侧位的x光片。观察手术鼓泡外耳道轮廓的中断(箭头)。

 

 

FIGURE 4 - Macroscopic aspect of the tympanic bulla of cat 23 from group B2. The concavity of the operated bulla (o) is similar to the normal one (n). Observe the slight protuberance in the inner surface of the larger compartment (arrow).

图4 - B2组23只猫的鼓泡宏观切面。手术鼓泡(o)的凹度与正常鼓泡(n)相似。观察大腔室内表面的轻微突起(箭头)。

 

 

FIGURE 5 - Photomicrograph of the operated tympanic bulla of cat 35 from group B1. The arrow indicates connective tissue present at the osteotomy site. Observe the bone tissue (asterisk) (HE, 40x).

图5 - B1组35只猫手术后鼓泡显微照片。箭头表示截骨部位的结缔组织。观察骨组织(星号)(HE, 40x)。

 

 

TABLE 1 – Connective tissue length in mm at the osteotomy site of bullae of B1 group (8 weeks of postoperative) and B2 group (16 weeks of postoperative) measured by the histomorphometry.

表1 -用组织形态测量法测量B1组(术后8周)和B2组(术后16周)鼓泡截骨部位结缔组织长度(mm)。

 

 

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