Importance of Diameter of Long Process of Incus in Stapedotomy-New Findings From In Vivo Study

Abstract Introduction Stapes surgery for otosclerosis is a precise surgical procedure. To achieve excellent hearing results, a firm and stable attachment of the prosthesis to the long process of incus (LPI) is necessary. The present study provides details on the attachment site in two dimensions to choose an appropriate prosthesis and to ensure firm attachment for better surgical outcomes. Objective To study the diameter of the LPI and its relevance in determining the piston, used in stapes surgery by an in vivo method. Methods This study was conducted in 41 patients who underwent stapedotomy, where both Anteroposterior (AP) and Mediolateral (ML) diameters of the LPI were measured at the site of attachment of the piston using specially designed instruments, intraoperatively. Radiological data were obtained to measure the LPI diameter from the normal ears of 46 patients. It was measured from both the right and left side, hence 92 LPI diameters were obtained. Results The most commonly used site for prosthesis attachment is between 1-1.5 mm away from the tip of the LPI. We found great variability in the diameters of LPI in the attachment site, with the AP diameter ranging between 0.6 -1.5mm and the ML diameter ranging between 0.5mm-1.2mm. Conclusion Pistons by design have characteristics of gripping incus that will vary between types. Based on LPI dimensions, ideal piston types with appropriate inner loop diameters are suggested in this study. HRCT before surgery should include measurements of the LPI as a guide to the choice of the prosthesis during surgery.

Anatomical and morphometric study of goat middle ear ossicles (Capra aegagrus hircus) / [Estudo anatômico e morfométrico dos ossículos da orelha média de caprinos (Capra aegagrus hircus)]

The social and economic roles of goat farming in Northeastern Brazil, allied to the fact that the use of goat middle ear ossicles for research and human ear surgery training has not yet been proposed, justify the study of their applicability as an experimental model. The middle ears of 19 goats (Capra aegagrus hircus) from the bone collection of the Laboratory and Didactic Anatomy Museum of Domestic and Wild Animals of the Federal University of Vale do São Francisco (UNIVASF) were dissected. The malleus, incus, and stapes were evaluated regarding their macroscopic morphology and biometry (length, width, and height). Ossicle morphology was similar to sheep, human, and bovine morphology. The malleus was 1.3 times heavier and 2.2 times longer than the incus, and 9.0 times heavier and 3.7 times longer than the stapes. The size relationship was positive between the stapes and the malleus and negative between the stapes and the incus. It is concluded that the middle ear size and the anatomical similarities with human ossicles make goats a useful model for experimental scientific studies, reconstructive surgery practice of the ossicular chain, and human ear surgery training.(AU)

Tanto o papel social quanto o econômico da caprinocultura na região Nordeste do Brasil, somados ao fato de que o uso de ossículos da orelha média de caprinos para estudos e treinamento cirúrgico otológico humano ainda não foi proposto, justificam o estudo de sua aplicabilidade como modelo experimental. Foram dissecadas as orelhas médias de 19 caprinos (Capra aegagrus hircus), provenientes do ossuário do Laboratório e Museu Didático de Anatomia dos Animais Domésticos e Silvestres - Universidade Federal do Vale do São Francisco. Martelos, bigornas e estribos tiveram a morfologia macroscópica e a biometria (comprimento, largura e altura) avaliadas. A morfologia dos ossículos assemelhou-se a de ovinos, humanos e bovinos. O martelo foi 1,3 vez mais pesado e 2,2 vezes mais comprido que a bigorna e 9,0 vezes mais pesado e 3,7 vezes mais comprido que o estribo. A relação de tamanho entre o estribo e o martelo foi positiva, e entre o estribo e a bigorna negativa. Conclui-se que o tamanho da orelha média e as semelhanças anatômicas com os ossículos humanos tornam os caprinos um modelo útil para estudos científicos experimentais, prática cirúrgica reconstrutiva da cadeia ossicular e treinamento cirúrgico otológico humano.(AU)

Study to Determine the Incus Bone Erosion Ratio on Mastoid Exploration in Cases of Chronic Suppurative Otitis Media with Middle Ear Cholesteatoma

Aim: To evaluate the frequency of incus bone erosion during mastoid exploration in chronic suppurative otitis media with cholesteatoma of the middle ear. Study design: A cross-sectional descriptive study. Place and duration: In the ENT Department of Services Hospital Lahore for the one-year duration from January 2018 to January 2019. Methods: 70 chronic suppurative otitis media patients with the middle ear cholesteatoma were prospectively evaluated and selected with a non-probability purposive sampling technique. The operation was performed on 70 patients under general anaesthesia in the operating room. A standard questionnaire was prepared and history, examination, laboratory data, and treatment were recorded for each patient. Results: One of the usual common diseases of the ear, nose and throat is chronic suppurative otitis media. Previously this disease was called atticoantral type was considered usually unsafe, is mostly caused by marginal perforation with cholesteatoma, the distinguishing feature of this condition and is taken as a complicating element. A total of 70 patients with chronic suppurative otitis media with middle ear cholesteatoma were included in the study. Forty-five (64.28%) are men and 25 (35.71%) are women. 2: 1 was the M: F ratio. There were 10 patients in the first age group from 1 to 10 years 10 (14.28%), in the second age group patients from 11 to 20 years 35 (50%), in the third age group 21-30 years 12 (17.14%), in the fourth age group, 31 to 40 years of age 5 (7.14%), in the fifth age group, 41 to 50 years age 5 (7.14%), and in the sixth age group, 3 patients were >50 years (4.28%). The mean ± standard deviation in the age group was 21.2 ± 11.9 years. The mastoidectomy was performed in 64 patients (91.42%) and a modified radical mastoidectomy was performed in 6 patients (8.57%). Bone erosion due to suppurative otitis media with middle ear cholesteatoma was absent in 59 patients (84.28%) and 11 patients (15.71%) without bone erosion.

Effect of Incudostapedial Reconstruction Using Conchal Cartilage Interposition Graft on Hearing Outcome

Abstract Introduction Chronic otitis media is a widely prevalent condition in developing countries and is a cause of correctable hearing loss. The most frequent ossicular chain defect found during surgery for chronic otitis media has been a discontinuity of the incudostapedial joint. This study observes the effect of incudostapedial reconstruction using conchal cartilage on the hearing of the patient. Objectives To evaluate improvement in hearing by incudostapedial reconstruction using conchal cartilage interposition graft in tympanoplasty and to identify the independent factors associated with erosion of the long process of incus among patients with chronic suppurative otitis media tubotympanic type. Methods This study was conducted in the department of ear, nose and throat (ENT) amongst 22 patients with tubotympanic-type chronic suppurative otitis media who were found to have erosion of the long process during tympanoplasty. These patients underwent incudostapedial reconstruction using conchal cartilage. Their hearing was again reassessed at 12 weeks postsurgery, and the changes were observed. Results A statistically significant improvement in air conduction by 15.14 dB was found after undergoing incudostapedial reconstruction using conchal cartilage (p < 0.001). There was no statistically significant change in bone conduction (p value > 0.05). A total of 59.1% of patients in the study had an improvement in hearing ranging from11 to 20 dB. It was also found that 50% of the patients had a postoperative hearing of 10 to 20 dB. Conclusion Conchal cartilage interposition graft effectively improved hearing when used for the reconstruction of the incudostapedial joint during tympanoplasty in patients of chronic suppurative otitis media.

Usefulness Of Various Measurements Of Incus To Determine The Sexual Dimorphism

Background: The incus is the intermediately placed ear ossicle in the middle ear cavity between the malleus andthe stapes.Materials and Methods: In present study, various measurements of incus were taken for the purpose of sexualdimorphism. Out of total 60 incus used in the present study, 30 were retrieved from the male cadavers and 30were retrieved from the female cadavers.Results and Discussion: Mean of total length of incus, mean of total width of incus, mean of maximum distancebetween the tips of the processes of incus and mean of index of incus in male are more as compared to female inthe present study.Conclusion: Among all the measurements taken in the present study; total length of incus and total width of incushaving statistically significant difference between the male and female incus and both can be used for the sexualdimorphism of incus for Kachchhi Gujarati population of present study.

A study on the outcome of tympanoplasty with various graft materials

Background: Chronic Suppurative Otitis Media (CSOM) is one of the most common causes of preventable hearing loss especially in developing countries CSOM is a disease condition characterized by persistent perforation of tympanic membrane with recurrent or persistent mucopurulent Otorrhoea Aim: This study was undertaken to review the outcomes (hearing improvement) achieved by using various graft materials like temporalis fascia (TF), tragal cartilage (TC), Conchal cartilage (CC), autologous sculpted incus (I), autologous cortical bone (BG) in tympanoplasty surgery Material and methods: This study comprised of 14 males and 16 females patients with age ranging from 12 years to 55 years They were selected for surgery after adequate history taking, clinical, otoscopic and microscopic examination Type 1 tympanoplasty was done in 19 patients, Type 3 tympanoplasty + Modified Radical Mastoidectomy (MRM) was done in 11 patients by using various graft materials The results were evaluated in the form of rate of graft success, hearing gain, and the pre and post-operative Air Bone gap Results: Out of 30 patients, in 20 TF graft patients AB gap improvement seen in 14 patients, 5 patients did not show any change and 1 patient did not come for follow up In 2 TC graft patients, both showed improvement in AB gap In 1 patient where CC graft was used showed improvement in AB gap In 6 patients I graft was used, 2 patients showed improvement, 2 patients did not show any change, 1 patient did not come for follow up and in 1 patient AB gap worsened In 1 patient BG was used and no change in AB gap was seen Out of 30 cases graft uptake was seen in 25 cases and graft rejection was seen in 3 cases and 2 patients did not come for follow up Graft rejection was documented in one case where TF was used, one case where incus graft was used and in another case where BG was used Harinarayana N, Srikanth M A study on the outcome of tympanoplasty with various graft materials IAIM, 2018; 5(12): 77- 82 Page 78 Conclusion: Post-operative hearing gain obtained was found to be better in patients operated upon with tubotympanic disease than those operated upon with atticoantral disease The post-operative hearing improvement depends not only on the graft material used and the type of tympanoplasty but also on the pre-operative status of the ossicular chain

Low power consumption structure design of an incus-stimulating middle ear implant based on piezoelectric stack / 医用生物力学

Objective To improve the design plan and get a piezoelectric actuator with displacement magnification structure,so as to reduce power consumption of the existing incus-stimulating piezoelectric actuator for middle ear implant.Methods Based on anatomical structure of human ear,the piezoelectric actuator with displacement magnification structure,and the one only composed of piezoelectric stack were designed,respectively,then the corresponding coupled mechanical models of the middle ear with the piezoelectric actuator were established.By comparing the calculation results from the two types of coupled mechanical models,the hearing compensation property and power consumption of the actuator before and after the implantation with the displacement magnification structure were analyzed.Results After adding the displacement magnification structure,the sound pressure level (SPL) at 1 kHz frequency was increased from 100 dB to 113 dB when the piezoelectric actuator was stimulated by 10.5 V effective voltages.In addition,for the piezoelectric stack,its power consumption at the frequency of 1,2 and 4 kHz were 6.42,1.56 and 0.28 mW,respectively;after introducing the displacement magnification structure,the power consumption at the above-mentioned 3 frequencies decreased to 0.39,0.09 and 0.01 mW,respectively.Conclusions Piezoelectric actuator with displacement magnification structure in this study can improve hearing compensation ability of the incus-stimulating middle ear implant,and effectively reduce the power consumption.The research findings will help to further improve the structure design of middle ear implant,thus achieving better hearing compensation effect.

A Case of Incus Extrusion into the External Auditory Canal after Head Trauma

Various types of ossicular chain interruption may occur in temporal bone fractures. The most common type is incudostapedial joint disruption. Incus is the most vulnerable to traumatic injury as compared with malleus or stapes, because it is suspended only by ligamentous structures and connected to the incudomalleolar and incudostapedial joints. Incus may rarely be pushed through tympanic membrane or pass through a fracture of posterosuperior external auditory canal. However, a case of complete extrusion of incus into the external auditory canal has not been reported. The author presents a rare case of incus extrusion into the external auditory canal with temporal bone fracture after head trauma.

Low power consumption structure design of an incus-stimulating middle ear implant based on piezoelectric stack / 医用生物力学

Objective To design an improvement plan of piezoelectric actuator with displacement magnification structure, so as to reduce power consumption of the existing incus-stimulating piezoelectric actuator for middle ear implant. Methods First, based on anatomical structure of human ear, the piezoelectric actuator with displacement magnification structure and the one just composed of piezoelectric stack were designed, respectively, and the corresponding coupled mechanical models of the middle ear and the piezoelectric actuator were established. By comparing the calculation results from the two types of coupling mechanical models, the hearing compensation property and power consumption of the actuator before and after the implantation of displacement magnification structure were analyzed. Results After adding the displacement magnification structure, the sound pressure level (SPL) at 1 kHz frequency was increased from 100 dB to 113 dB, when the piezoelectric actuator was stimulated by 10.5 V effective voltage. In addition, when the actuator was stimulated by the piezoelectric stack, its power consumption at the frequency of 1, 2 and 4 kHz were 6.42, 1.56 and 0.28 mW, respectviely; after introducing the displacement magnification structure, power consumption at the above-mentioned 3 frequencies decreased to 0.39, 0.09 and 0.01 mW, resepectively. Conclusions Piezoelectric actuator with displacement magnification structure in this study can improve hearing compensation ability of the incus-stimulating middle ear implant and effectively reducing the power consumption. The research findings will help to further improve the structure design of middle ear implant, thus achieving better hearing compensation effect.

Low power consumption structure design of an incus-stimulating middle ear implant based on piezoelectric stack / 医用生物力学

Objective To improve the design plan and get a piezoelectric actuator with displacement magnification structure,so as to reduce power consumption of the existing incus-stimulating piezoelectric actuator for middle ear implant.Methods Based on anatomical structure of human ear,the piezoelectric actuator with displacement magnification structure,and the one only composed of piezoelectric stack were designed,respectively,then the corresponding coupled mechanical models of the middle ear with the piezoelectric actuator were established.By comparing the calculation results from the two types of coupled mechanical models,the hearing compensation property and power consumption of the actuator before and after the implantation with the displacement magnification structure were analyzed.Results After adding the displacement magnification structure,the sound pressure level (SPL) at 1 kHz frequency was increased from 100 dB to 113 dB when the piezoelectric actuator was stimulated by 10.5 V effective voltages.In addition,for the piezoelectric stack,its power consumption at the frequency of 1,2 and 4 kHz were 6.42,1.56 and 0.28 mW,respectively;after introducing the displacement magnification structure,the power consumption at the above-mentioned 3 frequencies decreased to 0.39,0.09 and 0.01 mW,respectively.Conclusions Piezoelectric actuator with displacement magnification structure in this study can improve hearing compensation ability of the incus-stimulating middle ear implant,and effectively reduce the power consumption.The research findings will help to further improve the structure design of middle ear implant,thus achieving better hearing compensation effect.

Low power consumption structure design of an incus-stimulating middle ear implant based on piezoelectric stack / 医用生物力学

Objective To improve the design plan and get a piezoelectric actuator with displacement magnification structure,so as to reduce power consumption of the existing incus-stimulating piezoelectric actuator for middle ear implant.Methods Based on anatomical structure of human ear,the piezoelectric actuator with displacement magnification structure,and the one only composed of piezoelectric stack were designed,respectively,then the corresponding coupled mechanical models of the middle ear with the piezoelectric actuator were established.By comparing the calculation results from the two types of coupled mechanical models,the hearing compensation property and power consumption of the actuator before and after the implantation with the displacement magnification structure were analyzed.Results After adding the displacement magnification structure,the sound pressure level (SPL) at 1 kHz frequency was increased from 100 dB to 113 dB when the piezoelectric actuator was stimulated by 10.5 V effective voltages.In addition,for the piezoelectric stack,its power consumption at the frequency of 1,2 and 4 kHz were 6.42,1.56 and 0.28 mW,respectively;after introducing the displacement magnification structure,the power consumption at the above-mentioned 3 frequencies decreased to 0.39,0.09 and 0.01 mW,respectively.Conclusions Piezoelectric actuator with displacement magnification structure in this study can improve hearing compensation ability of the incus-stimulating middle ear implant,and effectively reduce the power consumption.The research findings will help to further improve the structure design of middle ear implant,thus achieving better hearing compensation effect.

Minocycline Induced Ossicular Chain Pigmentation.

Pigmentation is a well-recognized complication of minocycline use. This is the first reported case of ossicular chain pigmentation as a consequence of this drug. Isolated pigmentation of the lenticular process of the incus bone was noted. The structural integrity and function of the ossicular chain was not influenced by these changes.

Use of incus as an interposition graft in ossiculoplasty for type IIb tympanoplasty.

Background: In cases of chronic suppurative otitis media, the most common cause for the discontinuity in the ossicular chain is erosion of lenticular or long process of incus. To study hearing results, sequel and complications of using autologous incus as interposition graft in type IIb osiculoplasty. Methods: We studied 30 patients who required ossiculoplasty using autologous incus. The pre-operative audiograms were done. Post operatively patients were followed up to 2 years during which complete otological examination with audiogram was done. Results: According to the American Academy of Otolaryngology-Head and Neck Surgery guidelines, a successful hearing result is the one with post-operative air-bone gap of 20 decibels or less. Hence, by this standard our success rate is 77 percent and in all of our patients we have air-bone gap closure to below 30 decibles. Average closure in air-bone gap (gain) in our patients is 25.9 decibles with average pre-operative and post-operative air-bone gap being 47.70 decibles and 16.9 decibles there was no extrusion of incus. 3 patients had residual perforation and 2 patients had retracted grafts. All the patients with retracted grafts or residual perforation had oedematous middle ear mucosa and Eustachian tube dysfunction and high MER index. Conclusions: Autologous incus is an excellent interposition graft for ossiculoplasty. There is no risk of transmission of disease and no extra cost involved. Higher values of Middle Ear Risk Index, oedematous middle ear mucosa and Eustachian tube dysfunction are poor prognostic factor for success of ossiculoplasty.

Morphological variations in human fetal ear ossicles-a study.

Aim: To study the morphological variation, if any, of the ear ossicles in the human fetuses and use of the study in medical applications. Materials and Methods: This study was performed on 100 sets of middle ear ossicles, each set consisting of Malleus, Incus and Stapes, which were taken from 50 fetal cadavers on either side. Observations: All the three ossicles showed variations in their morphology and more so in the stapes. Discussion: There are few studies in the literature on individual differences in these ossicles and these studies were on either adult or different species. Conclusion: the ear ossicles of the destitute human fetuses can be used as homografts to replace eroded adult middle ear ossicles.

Antropometría del yunque y articulaciones incudo-maleolar e incudo-estapedial en humanos: un estudio anatómico directo / Anthropometry of the incus and incudomalleolar and incudostapedial joints in humans: a direct anatomical study

Los estudios actuales sobre variaciones anatómicas del yunque en humanos a partir del registro morfométrico son insuficientes. Las características estructurales y dimensionales del yunque son registradas en 23 muestras de población mestiza adulta Colombiana. Las medidas registradas involucraron el cuerpo, la articulación incudo-maleolar, el proceso largo, el proceso corto y la articulación incudo-estapedial. Solo ocho de los treinta y cinco registros tomados en este estudio pudieron ser comparados concienzudamente con otros estudios anteriores que mostraron similitudes. El largo total del yunque fue de 6,51 mm (DE 0,32), la longitud del proceso largo del yunque fue de 5,35 mm (DE 0,25), la distancia entre proceso largo y corta fue de 6,06 mm (DE 0,35) y la proporción de longitudes entre ambos procesos fue de 82,18 por ciento (DE 8,9). Conforme a la población estudiada se encontró variación pareada en la anatomía del yunque en solo tres de los registros tomados, sin embargo, consideramos que es un hueso morfométricamente uniforme y estable.

Current studies on anatomical variations of the incus in humans from the morphometric register are insufficient. Structural and dimensional characteristics of the incus are registered in 23 samples of Colombian adult mestizo population. Registered measures involved incus body, incudo-maleolar joint, long process, short process and incudo-stapedial joint. Only eight of the thirty-five records taken in this study could be thoroughly compared to other anterior studies, which showed similarities. The total length of the anvil was 6,51 mm (SD 0.32), the length of the long process of the incus was 5.35 mm (SD 0.25), the distance between processes long and short was 6.06 mm (SD 0.35) and the ratio of lengths between both processes was 82.18 percent (SD 8.9 percent). In accordance with the studied population we found paired variation in the anatomy of the incus in only three of the records taken, however, we believe that it is a uniform and morphometrically stable bone.

Audiologic Results of Ossiculoplasty Using Malleus Footplate Assembly: The Comparison between Autologous Incus and Hydroxyapatite

BACKGROUND AND OBJECTIVES: Absence of incus is one of the most common ossicular anomalies and also frequently found in chronic otitis media or chornic otitis media with cholesteatoma. Ossiculoplasty with malleus footplate assembly (MFA) can be an excellent option in the above situations. We reviewed our procedures and evaluated the hearing results of ossiculoplasty using the MFA. SUBJECTS AND METHODS: This study retrospectively reviews a series of 32 patients who underwent MFA ossiculoplasty between September 2001 and March 2010 in an academic tertiary referral center. The autologous incus or hydroxyapatite (HA) was used as materials for reconstruction. RESULTS: Thirteen of 32 patients (40.6%) had ossicular chain anomaly, 9 patients (28.1%) had congenital cholesteatoma and 8 patients (25.0%) had chronic otitis media with cholesteatoma and 2 patients (6.3%) had chronic otitis media. The patients with ossicular chain ano-maly showed the greatest air-bone gap (ABG) closure. Overall, postoperative ABG was 17.7+/-11.7 dB at postoperative 6 months and 19.7+/-14.3 dB at postoperative 1 year, compared with preoperative ABG of 37.9+/-9.3 dB. There was no statistical difference of ABG at postoperative 12 months, 24 months between MFA using incus (n=17) and HA (n=15)(p=0.300, and p=0.563). There was no meaningful difference of postoperative ABG between the patients with combined mastoidectomy (n=10) and those without mastoidecmoy (n=22)(p=0.555). No extrusions occurred. CONCLUSIONS: MFA can be an effective option in the case of absent incus expecting good postoperative hearing results.

Human oscicular chain articulations: asymmetric sound transmission / Articulaciones de la cadena oscicular humana: transmisión asimétrica del sonido

The mechanism for conducting acoustic energy via middle ear oscicles is still a controversial topic and will remain so until consensus is reached regarding whether it amplifies or reduces sound transmission. 22 paired human temporal bone blocks and 1 left block were studied. Digital measurements were taken of the tympanic membrane, oscicular articulations and the oval window; the results were then correlated. A relationship of non-lineal areas was found amongst the structures being studied, suggesting a sound transmission relationship combining both sound reduction and amplification. A complex relationship of levers could be observed originating in an oscicular and articular asymmetric relationship suggesting an amplifying function in initial sound transmission and also a final reducer destination for such conduction.

El mecanismo para conducir la energía acústica a través de oscículos del oído medio es todavía un tema controvertido y lo seguirá siendo hasta alcanzar un consenso con respecto a si se amplía o reduce la transmisión del sonido. Fueron estudiados 22 pares de bloques de hueso temporal izquierdo y uno derecho hmanos. Mediciones digitales fueron tomadas de la membrana timpánica, articulaciones osciculares y de la ventana oval, siendo estos resultados correlacionados. Una relación de las áreas no-lineal se encontró entre las estructuras, lo que sugiere una relación de transmisión de sonido que incluye tanto la reducción de sonido y amplificación. Una compleja relación de las palancas se pudo observar originando una relación oscicular y articular asimétrica, lo que sugiere una función de amplificación de la transmisión del sonido inicial y también un destino reductor final para su conducción.

Isolated Congenital Incus Anomaly / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: A non-progressive and conductive hearing loss with normal eardrum, which has no history of trauma and infection is highly suggestive of a congenital ossicular malformation. Among ossicular anomalies, the most common anomalous ossicle is stapes. However, incus anomaly is sometimes encountered with or without stapes anomaly. The objectives of this study are to describe patterns of incus anomaly, encountered in patients who have a normal eardrum and to analyze their surgical results with special reference to the patterns of incus anomaly. SUBJECTS AND METHOD: We reviewed 26 patients (31 ears) with congenital incus anomaly, which were confirmed through exploratory tympanotomy at Ajou University Hospital from 1994 to 2005. We analyzed temporal bone CT, preoperative and postoperative audiometric findings, and surgical findings. RESULTS: 10 anomalous patterns were detected out of 31 cases of congenital incus anomaly. Incus without its long process was the most common anomalous pattern. In 15 out of 26 cases (57.7%), incus anomaly was associated with stapes anomaly, which was usually unilateral. We could get hearing improvement in 26 out of 31 ears (89.1%). CONCLUSION: Various anomalous patterns of incus were noted in our series. Incus anomaly was often associated with stapes anomaly, which was usually unilateral. The surgical result of incus anomaly was excellent except the cases without stapes.

A Case of Incus Dislocation into the External Auditory Canal after Head Trauma / 대한이비인후과학회지

Temporal bone fracture is usually the result of blunt head injury as ossicular disruption or isolated dislocation of individual ossicles may occur after temporal bone trauma. The incus is particularly prone to displacement because of its fragile ligamentous support. We report a rare case of incus dislocation into the external auditory canal associated with an underlying temporal bone fracture.

Clinical observe of the middle ear malformation / 临床耳鼻咽喉头颈外科杂志

Objective: To analyze the diagnosis and therapeutic effect of the middle ear abnormalities.Method: 65 ears from 1967 to 1996 were reviewed. The degrees of the ossicular abnormalities were analyzed,operative effect were valued. Result:In the 65 ears,incus abnormalities was 57 ears (87.7％),stapes was 55 ears(84.6％), mixed malformation was dominant. 47 ears were operated with ossicular chain reconstruction. 44 ears(93.6％) had hearing improvement, 32ears (68.1％) had obviously improvement (＞20 dB). They werefollowed up over one year, 44 ears had steadily heraring and had not any complications. Conclusion:If diagnosisand interference were all proper, operation would obtain good result.