中耳机械模型的建立及听骨赝复物传音特性的研究

目的探讨对人工听骨赝复物传音功能进行评价的客观方法，以及钛金属人工听骨赝复物不同质量和不同顶盘面积在中耳机械模型中对传音功能的影响。方法用两块圆形的弹性膜分别代替鼓膜和前庭窗，两膜之间放置人工听骨，在人工外耳道侧给予纯音刺激，同时记录其声强，在前庭窗膜处用激光测振仪测量前庭窗膜的振动速度，通过比较振动速度的大小来比较人工听骨的传音特性；将质量不同和面积不同的2组钛人工听骨分别安放于中耳机械模型中测量其传音特性。结果模型感觉阈曲线和正常人听阈曲线对比，两者走势基本相同。钛听骨顶盘面积较小的听骨在1500-4000Hz其传音特性优于顶盘面积较大的听骨；质量小的听骨在高频区传音好，质量大的听骨在低频区传音比较好，但总体上质量小的听骨传音特性较好。结论中耳机械模型是检验人工听骨传音特性并进行人工听骨赝复物客观评价的理想工具之一；钛人工听骨的质量和顶盘的面积对其传音特性均有影响，在设计人工听骨时或手术要同时考虑到质量和顶盘面积对传音的影响。     

The leaking labyrinthine lesion resulting from direct force through the auditory canal: report of five cases

The leaking labyrinthine lesion is treated by conservative methods or surgical procedures. With respect to the stapes, the surgical treatment is controversial. Five cases of middle ear injuries accompanying oval window rupture are reported herein. In each case, direct force through the auditory canal damaged not only the ossicular chain but also the oval window. Initial symptoms were sudden hearing loss with significant conductive disturbance and various degrees of unsteadiness. Spontaneous horizontal nystagmus directed toward the uninvolved ear was observed in each case. Tympanic cavities were promptly explored under general anesthesia and oval window injuries were confirmed. In each case, the damaged stapes was temporally removed from the oval window. Perilymphatic leakage was recognized in each case. Two patients had subluxation of the stapes with a paucity leakage. Three had complete luxation of the stapes with a relatively huge oval window fistula. Disrupted oval windows were repaired with temporalis muscle fascial grafts that were inserted under the middle ear mucosae surrounding the oval windows. The stapes were replaced in the repaired oval windows, and the ossicular chains were reconstructed without artificial grafts. Vestibular dysfunctions disappeared within 7 days, and satisfactory audiologic results were obtained in each case.     

Comparative study of the clinical results obtained by means of Plastipore and ceramic ossicular prosthesis and bone allografts

We present a comparative study of the clinical and audiologic results obtained by means of Plastipore and ceramic ossicular prostheses and bone allografts in reconstructive middle ear surgery. We stress the excellent tolerance for ceramic and bone allografts in comparison to Plastipore. Functionally, the best results were obtained with partial prostheses using bone allografts and with total ceramic ossicular prostheses. Air-bone gaps less than 10 dB (37%) and 20 dB (69%) were achieved in patients with partial prostheses; in patients with total prostheses, 38% had an air-bone gap of less than 10 dB and 62% of less than 20 dB.     

Tissue reactions to glass ceramics in the middle ear*

The bioactive glass ceramic ‘Ceravital’ was used to fashion protheses for the replacement of various ossicles in the middle ear. They were tested in 70 rabbit ears, where they were accepted in osseous areas without formation of surrounding fibrous tissue. Histological examinations regularly showed an osseous bond with the surrounding bony tissue. Mucous membrane covered these ossicular chain prostheses and showed no evidence of inflammatory reactions. Glass ceramic implants were also used to reconstruct the ossicular chain and the posterior wall of the outer ear canal in 100 patients. The functional results were satisfactory in all cases.     

Congenital absence of the oval window

From 1983 to 1987, seven patients with conductive hearing loss were found to have congenital absence of the oval window. Six of these patients underwent vestibulotomies and reconstruction with House wires or total ossicular reconstruction prostheses. Surgical findings included absent or rudimentary stapes in all cases, abnormal facial nerves in four cases, and abnormal long processes of the incus in four cases. All patients had normal external ear canals and tympanic membranes. Hearing initially improved 20 to 45 dB in four of the six patients reconstructed. Over time, however, much of this initial hearing gain was lost. A marked difference in hearing results was evident between this series of absent oval window cases and a recent series of major atresia cases.     

单纯中耳畸形的临床分析

目的 :分析单纯中耳畸形的临床和听力学特征 ,手术探查明确畸形形式 ,避免和减少对该病的误诊、误治。方法 :9例 11耳单纯性中耳畸形患者均行鼓室探查术 ,部分行听骨链重建术 ,其中 ,行镫骨切除加钢丝结绨组织栓人工听骨重建 4耳 ,前庭开窗加人工听骨重建 2耳 ,砧镫关节松解术 1耳 ,高分子材料TORP重建听骨1例 ,蜗窗不明确的 3耳 ,仅做鼓室探查。结果 :术中发现砧骨畸形最多 (10 / 11) ,豆状突细小或缺失 ,砧骨游离 ,长突缺失、变细或变粗 ;镫骨缺如 (2 / 11) ;其他 (7/ 11)包括镫骨不完整或游离、固定、前后脚融合 ;砧镫关节粘连(1/ 11) ;面神经和前庭窗无法辨认 (4 / 11) ;鼓岬表面凹凸不平 ,无法辨认圆窗 (3/ 11)。 3例并发其他全身异常。听骨重建后患者听力满意 ,纯音测听示低频比高频提高明显 ,言语频率平均提高 2 4dB。无并发症发生。结论 :单纯先天中耳畸形最终确诊靠鼓室探查术 ,一定条件下镫骨切除或前庭开窗加钢丝结绨组织栓人工听骨重建术可满意提高听力     

听骨链CT扫描并三维重建的临床应用

目的:探讨CT仿真内镜(CTVE)显示中耳正常结构的显示方法,评价中耳病变特别是听骨链连接状态的价值及意义,确立显示听骨链及其他中耳结构的位点和方法。方法:选择40例无耳科疾病的志愿者(正常组)和30例疑有中耳疾病的患者(病例组),分别采用德国西门子(Siemens SOMATOM Sensation 16)螺旋CT机Inner Ear扫描程序对患者进行轴位扫描,重建原始图像,用Fly-through软件经选择的A、B、C点入路进行CTVE成像研究。重点显示听骨链连接状态,并对慢性中耳炎的显示结果与手术中探查图像进行对照。结果:正常组CTVE中锤骨、砧骨、鼓岬、面神经管水平段、外半规管隆凸显示率均为100%;而镫骨头、两足弓的显示率在3个显示层面则分别为57.5%、70.0%,97.5%;圆窗、卵圆窗为90.0%、93.0%、97.5%。在中耳炎、外伤、颞骨畸形等情况下可显示听小骨损伤、移位、中断、缺失和畸形。结论:CTVE在显示3个听小骨之间的链接关系(如中断等方面)有一定优势。通过选择恰当的入路,CTVE在显示听小骨及其链接关系以及病理状态方面有相当优势。通过比较CTVE在3个不同显示层面观察镫骨的能力,明确CTVE是断层影像的有利补充。     

Severe injury of the middle ear

The author reports on a rare case of direct injury of the middle ear with elective luxation of the stapes in vestibulum, where the rest of the ossicular chain was intact. The patient had a paroxysmal vertigo and combined hearing loss. The stapes was extracted from the vestibulum the same day and was fixed to the incus with fibrin sealant in an anatomical position. The oval window was sealed with connective tissue. The inner ear function recovered immediately. After one year, the audiogram was normal and the stapedial reflex was present.     

Middle ear mechanics and their interface with respect to implantable electronic otologic devices

The understanding of construction principles of the middle ear and its mechanical behavior is valuable in the development of implantable hearing aids, as these devices have to adapt to the mechanics of the normal middle ear for optimal function. The input of the vibrational energy of a transducer into the ossicular chain follows the same mechanical fundamentals as in passive prostheses. Many aspects of middle ear mechanics, which are relevant for the acoustic quality of ossicular prostheses thus are also applicable for implantable transducers: the direction of vibrational mode, the stability of the contact zone between driver and ossicles, the increase of mass and impedance of the vibratory elements in the middle ear, the performance at changes of ambient air pressure, the potential feed back effects, and so forth.     

The facial nerve in congenital middle ear malformations

The two most common anomalies of the facial nerve encountered in patients with a congenital malformation of the middle ear are displacement of the nerve and lack of a bony cover, two conditions that place the nerve at risk of being injured by the unwary surgeon. Malformations of the stapes are often found in association with facial nerve anomalies and may range from underdevelopment to complete absence. A congenital absence of the oval window is not uncommon. The position of the facial nerve in relation to the location and maturation of the ossicles will determine the method of ossicular chain repair. Creation of a new oval window by drilling may require the surgeon to purposely displace the facial nerve to ensure a more direct alignment of the prosthesis with the vestibule. Any part of the incus or malleus may be contoured by drilling to accommodate the loop end of the wire-piston prosthesis. An aberrant course of the facial nerve was found in 13/54 (24%) ears having a congenital malformation of the middle ear. All 54 ears had a patent external ear canal and an identifiable tympanic membrane. Patients with atresia or stenosis of the external ear canal were specifically excluded from this study.     

Effect of middle ear fluid on sound transmission and auditory brainstem response in guinea pigs

Combined measurements of middle ear transfer function and auditory brainstem response (ABR) in live guinea pigs with middle ear effusion (MEE) are reported in this paper. The MEE model was created by injecting saline into the middle ear cavity. Vibrations of the tympanic membrane (TM), the tip of the incus, and the round window membrane (RWM) were measured with a laser vibrometer at frequencies of 0.2-40?kHz when the middle ear fluid increased from 0 to 0.2?ml (i.e., full fill of the cavity). The click and pure tone ABRs were recorded as the middle ear fluid increased. Fluid introduction reduced mobility of the TM, incus and RWM mainly at high frequencies (f?>?1?kHz). The magnitude of this reduction was related to the volume of fluid. The displacement transmission ratio of the TM to incus varied with frequency and fluid level. The volume displacement ratio of the oval window to round window was approximately 1.0 over most frequencies. Elevation of ABR thresholds and prolongation of ABR latencies were observed as fluid level increased. Reduction of TM displacement correlated well with elevation of ABR threshold at 0.5-8?kHz. Alterations in the ratio of ossicular displacements before and after fluid induction are consistent with fluid-induced changes in complex ossicular motions.     

Fibrin tissue adhesive and glass ceramic strut for ossicular chain replacement. Electrophysiologic and histologic findings

The tolerance of the inner ear to fibrin tissue adhesive was tested. In experimental surgery on thirty-four chinchilla ears, Fibrin Sealant was applied to the inner ear contents by closing the oval window with a connective tissue graft dipped in the adhesive and gluing a Macor glass ceramic strut between this graft and tympanic membrane. No inner ear changes or tissue damage were found. The loss in auditory sensitivity monitored by auditory brain stem response thresholds was commensurate with the amount of loss to be expected with ossicular chain replacement. The findings suggest that this tissue glue can be safely applied to the labyrinth.     

Die Therapie der Tympanosklerose

Tympanosclerosis is a scarring process with a remarkable variability in its localization within the middle ear. It can lead to conductive hearing loss in many cases. It is usually caused by recurrent chronic inflammation of the middle ear. It is generally accepted that functionally relevant tympanosclerotic findings of the middle ear structures should be treated by surgery. Depending on the extent of the surgical resection, the tympanic membrane and the ossicular chain must be reconstructed individually. In cases of isolated myringosclerosis with no hearing loss, no surgery is required. When the ossicular chain is affected by the sclerosis, sound conduction can often be restored only by interposition of grafts. Stapes footplate fixation can be treated by a stapesplasty. Tympanosclerosis of the oval window combined with other chronic inflammation usually requires two-stage surgery. Tympanosclerotic findings without any clinical symptoms should not be removed. The fitting of conventional or implantable hearing aids is the only treatment if chain reconstruction fails or is impossible.     

Treatment of tympanosclerosis

Tympanosclerosis is a scarring process with a remarkable variability in its localization within the middle ear. It can lead to conductive hearing loss in many cases. It is usually caused by recurrent chronic inflammation of the middle ear. It is generally accepted that functionally relevant tympanosclerotic findings of the middle ear structures should be treated by surgery. Depending on the extent of the surgical resection, the tympanic membrane and the ossicular chain must be reconstructed individually. In cases of isolated myringosclerosis with no hearing loss, no surgery is required. When the ossicular chain is affected by the sclerosis, sound conduction can often be restored only by interposition of grafts. Stapes footplate fixation can be treated by a stapesplasty. Tympanosclerosis of the oval window combined with other chronic inflammation usually requires two-stage surgery. Tympanosclerotic findings without any clinical symptoms should not be removed. The fitting of conventional or implantable hearing aids is the only treatment if chain reconstruction fails or is impossible.     

Vestibulotomy about the displaced facial nerve]

OBJECTIVE: To investigate the feasibility of vestibulotomy above the displaced facial nerve. METHODS: From January 2000 to January 2002, eight patients with severe congenital conductive hearing loss underwent the vestibulotomy above displaced facial nerve and reconstruction of the ossicular chain with a total ossicular replacement prosthesis, which all for the congenital middle ear deformity and the facial nerve overhang and concealed the oval window niche or lied inferior to the oval window. In four of eight cases, the facial nerve was transposed in order to access the oval window niche. RESULTS: Hearing of this patients improved 15 dB in 2 ears, 16-25 dB in 3 ears and 26 dB or more in 3 ears. In no case was there a postoperative facial paresis. With 4 months to 28 months follow-up, the postoperative hearing gain was stable. CONCLUSIONS: Vestibulotomy above displacement of the facial nerve allows a final chance of achieving serviceable hearing through surgery. The lack of facial nerve injury and the potential for hearing restoration make this procedure feasible in otherwise marginal or poor surgical candidates.     

Experimental investigations on middle ear prostheses with an integrated micro joint

BACKGROUND: Quasi static pressure changes as they occur in altitude changes or Valsalva's manoeuvre are causing great tympanic membrane displacements. These can produce a prosthesis dislocation from the stapes footplate, in case of using a TORP for reconstruction. Additionally, prostheses extrusions can occur in the chronically poor ventilated middle ear. Anatomical studies on the ostrich demonstrate that the flexible columella in the avian middle ear provides a good sound transmission and features an effective inner ear protection in pressure changes. MATERIAL AND METHODS: Focusing on this bionic attempt, we designed a new micro joint TORP by interposing a silicone ball joint in the prosthesis shaft. This prototype was used for frequency response measurements with the laser Doppler vibrometer in the ventilated middle ear and under conditions of increased pressure in the external auditory canal. RESULTS: Frequency response measurements showed comparable results to those using a conventional TORP. Investigations on pressure changes in the external auditory canal demonstrated a significant decrease in footplate excursion after reconstruction with the new micro-joint prosthesis then compared to a common TORP. CONCLUSIONS: The insertion of the new silicone bordered micro joint into a TORP shaft provides an effective method to decrease the potentially damaging stapes footplate excursions after complete ossicular reconstruction. Limited deflections of the prosthesis shaft reduce the occurring forces on the stapes footplate as they partly bore the quasi static pressure changes. Thus, the micro joint can reduce the risk of prostheses dislocation and annular ligament damage and is additionally providing a proper sound transmission through the reconstructed middle ear. Moreover, the bionic modification of a TORP reflects the remaining possibilities for further improvements in prosthetic reconstruction.     

Tympanoplasty in pediatric patients

OBJECTIVE: The aim of this study is to analyze the clinical features and follow-up of a series of pediatric patients with chronic otitis media undergoing tymponaplasty surgery and to identify the effect of the factors on the course. METHODS: Forty-one children (mean age 15.1+/-2.62 years, range from 8 to 16 years) who had undergone tympanoplasty with or without ossicular reconstruction were evaluated. Age, gender, size and site of perforation, status of operated ear (dry/discharging), status of the contralateral ear, underlying cause of the perforations, surgical technique, preoperative and postoperative hearing levels, average postoperative follow-up time, and postoperative complications were recorded. RESULTS: Myringoplasty in 28 patients (68.3%), incus interposition in 7 patients (17.1%), partial ossicular replacement prostheses in 4 patients (9.7%) and total ossicular replacement prostheses in 2 patients (4.9%) were performed. In the 37 (90.2%) of patients, intact graft was determined during postoperative follow-up. Surgical success including intact graft and postoperative air-bone gap of less than 25 dB were obtained in 34 (82.9%) cases. CONCLUSIONS: The present study suggested that tympanoplasty was a quite successful method in the appropriate pediatric patients between the ages of 8 and 16 years. In the preoperative evaluation for surgery success, some factors, such as dry middle ear, healthy contralateral ear and concordant to postoperative care should be considered.     

Multifrequency tympanometry: experimental application after implantation of ossicular replacement prosthesis in rabbits.

HYPOTHESIS: We used multiple-frequency tympanometry (MFT) to evaluate the influence of a newly developed ossicular replacement prosthesis on transmission characteristics of middle ear. BACKGROUND: Multiple-frequency tympanometry is a technique for evaluating the emittance of the middle ear over a wide frequency range. It has been shown to be sensitive to certain middle ear conditions that are not detected by conventional 226-Hz tympanometry. In the field of experimental evaluation, MFT has been shown in certain animal studies to be useful in monitoring diseases. METHODS: Thirty-six prostheses composed of titanium dioxide ceramic were implanted into the right middle ear of female rabbits. Bilateral measurements using conventional 226-Hz and MFT were performed before implantation and after 28, 84, and 300 days postoperatively. The results of the preoperative examinations yielded reference values for physiological resonance frequency. After dissecting the temporal bone, we opened the middle ear and analyzed both the surrounding tissue and the position of the prosthesis. RESULTS: The constant values for compliance revealed by both preoperative and postoperative measurements indicate good reproducibility of 226-Hz tympanometry. Postoperatively, resonance frequency increased continuously up to the 300th day. The observation supports the assumption that the higher stiffness level of connective tissue influenced resonance frequency. CONCLUSION: The reference values in this study can serve as guidelines for further experimental trials.