Perspective on Temporomandibular Joint Disorder: Foramen Tympanicum Defect.

BACKGROUND: Foramen tympanicum (FT) is a defect located anterior-inferior to the external acoustic meatus. We evaluated its prevalence, location, size, and relationship with temporomandibular joint (TMJ) disorders. METHODS: Cone beam computed tomography was performed for 200 patients who presented to the Karamanoglu Mehmetbey University Ahmet Kelesoglu Faculty of Dentistry Hospital. The location and size of the FT in the axial and sagittal planes were evaluated. Descriptive statistics were used to compare the study parameters among age and sex groups. Patients with FT were reevaluated by two maxillofacial surgeons at the study centre. RESULTS: In total, 200 images from 400 joints were examined. Unilateral and bilateral FT (19 [9.5%] and 8 [4%], respectively) was detected in 35 (17.5%) images from 27 (13.5%) patients. Examinations were performed for TMJ disorders in 24 patients. Participants with bilateral defects had the highest rates of presence of sounds and ear pain on the left and right sides (p < .05). CONCLUSION: Foramen tympanicum can lead to TMJ disorders and spread of tumours or infections from the external auditory canal to the infratemporal fossa. The increased prevalence of such disorders in patients with bilateral FT suggests an association between them.

Morphological relationships between external auditory canal and vital structures of tympanic cavity.

PURPOSE: We aimed to evaluate the morphology of the external auditory canal (EAC) using a three-dimensional (3D) reconstruction of computed tomography (CT) scans of the temporal bone to corroborate and predict important anatomical structures involved in middle ear surgery based on the EAC morphology. METHODS: Temporal bone CT from 62 patients (120 ears) was used to perform 3D reconstruction (maximum intensity projection), of which 32 patients (60 ears) had chronic otitis media and 30 patients (60 ears) had normal temporal bones. The anatomical morphology of the EAC, tympanic sinus, vertical portion of the facial nerve, and jugular bulb were measured, and the anatomical relationship between the EAC morphology and important structures of the middle ear was analyzed. RESULTS: In ears with chronic otitis media, the overhang of the inferior wall of the EAC was significantly more than that in normal ears, and the antero-posterior length of the bony tympanic ring was short. Furthermore, the tympanic sinus was shallow, and vertical portion of the facial nerve tended to run outward. The EAC morphology correlated with the tympanic sinus depth and outward orientation of the vertical portion of the facial nerve. CONCLUSION: A severe overhang of the inferior wall of the EAC and short antero-posterior length of the bony tympanic ring indicates a higher possibility of a shallow tympanic sinus and an outward orientation of the vertical portion of the facial nerve. These findings aid in predicting the difficulty of tympanic sinus operation and reducing facial nerve damage risk during EAC excision.

Extracranial landmarks for surgical skull base approaches / Puntos de referencia extracraneales para abordajes quirúrgicos de la base del cráneo

SUMMARY: Surgical operations regarding to skull base are challenging and reliable anatomical landmarks are required. There is a lack of knowledge on anatomical variations in this region. The aim of this study was to determine the safe extracranial landmarks for surgical approach to the skull base. In this study, 23 adult dry skulls were evaluated: the age and sex of the specimens were unknown. All measurements were taken from external surface of inferior aspect of the skull by using digital calipers accurate to 0.01 mm. In right and left sides; the distances between the external acoustic meatus (EAM) and the following anatomical landmarks were measured: articular tubercle (AT); anterior margin of squamous suture (ASS); superior margin of squamous suture (SSS); posterior margin of squamous suture (PSS); end point of styloid process (SP); midpoints of pterygomaxillary fissure (PMF); foramen ovale (FO); foramen spinosum (FS); and of carotid canal (CC).The distances of the external acoustic meatus to the anatomical structures on the right and left sides were: EAM-SP; 24.24±3.19 mm, 23.16±3.17 mm; EAM-PMF; 46.56±4.51mm, 46.25±3.96 mm; EAM-FO; 27.57±2.87 mm, 28.70±2.85 mm; EAM-FS; 22.53±3.19 mm, 22.72±3.47 mm; EAM-CC; 17.35±3.56 mm, 17.19±3.39 mm; EAM-AT; 19.31±3.79 mm, 18.95±3.42 mm; EAM-ASS; 43.14±4.80 mm, 46.82±4.61 mm; EAM-SSS; 49.17±4.74 mm, 48.83±3.34 mm and EAM-PSS; 36.15±4.24 mm, 35.39±4.25 mm, respectively. We think that the findings obtained from this study related to external acoustic meatus can be an important reference for surgical anatomy and surgical procedures in skull base.

RESUMEN: Las cirugías relacionadas con la base del cráneo son un desafío, las cuales requieren puntos de referencia anatómicos confiables. Existe una falta de conocimiento sobre las variaciones anatómicas en esta región. El objetivo de este estudio fue determinar los puntos de referencia extracraneales seguros para el abordaje quirúrgico de la base del cráneo. En este estudio se evaluaron 23 cráneos secos adultos: se desconocía la edad y el sexo de los ejemplares. Las medidas se tomaron de la superficie externa de la cara inferior del cráneo utilizando calibradores digitales con una precisión de 0,01 mm. En lados derecho e izquierdo se midieron las distancias entre el meato acústico externo (MAE) y los siguientes puntos de referencia anatómicos: tubérculo articular (TA); margen anterior de la sutura escamosa (MASE); margen superior de sutura escamosa (MSSE); margen posterior de sutura escamosa (MPSE); punto final del proceso estiloides (PFPE); puntos medios de la fisura pterigomaxilar (PMFP); foramen oval (FO); foramen espinoso (FE); y del canal carotídeo (CC). Las distancias del meato acústico externo a las estructuras anatómicas de los lados derecho e izquierdo fue- ron: MAE-PFPE; 24,24 ± 3,19 mm, 23,16 ± 3,17 mm; MAE-PMFP; 46,56 ± 4,51 mm, 46,25 ± 3,96 mm; MAE-FO; 27,57 ± 2,87 mm, 28,70 ± 2,85 mm; MAE-FE; 22,53 ± 3,19 mm, 22,72 ± 3,47 mm; MAE-CC; 17,35 ± 3,56 mm, 17,19 ± 3,39 mm; MAE-TA; 19,31 ± 3,79 mm, 18,95 ± 3,42 mm; MAE-MASE; 43,14 ± 4,80 mm, 46,82 ± 4,61 mm; MAE-MSSE; 49,17 ± 4,74 mm, 48,83 ± 3,34 mm y MAE-MPSE; 36,15 ± 4,24 mm, 35,39 ± 4,25 mm, respectivamente. Creemos que los hallazgos obtenidos de este estudio relacionados con el meato acústico externo pueden ser una referencia importante para la anatomía quirúrgica y los procedimientos quirúrgicos en la base del cráneo.

Estudio anatómico de la dehiscencia timpánica (foramen de Huschke) en la población arqueológica de Tutuquén, Región del Maule, Chile / Anatomical study of tympanic dehiscence (foramen of Huschke) in the archaeological population of Tutuquén, Maule Region, Chile

RESUMEN: La dehiscencia timpánica o Foramen de Huschke (FH) se considera un rasgo craneal morfológico menor, hipostósico, no estocástico, transitorio, ubicado en laplaca timpánica del hueso temporal, cuya expresión se considera fisiológica hasta los 5 años de edad, denominándose como persistente su presencia a mayor edad. La mención de este rasgo en la literatura anatómica se presenta de manera escasa, debido a una muy baja presencia en poblaciones modernas, situación que cambia al estudiar poblaciones arqueológicas. El propósito de este estudio es describir la expresión del foramen de Huschke en una población arqueológica de Chile central. Fueron analizados 27 huesos temporales obtenidos de los restos óseos de la población del Monumento Arqueológico Cementerio Tutuquén, los cuales están depositados en el Museo Regional de Rancagua, Chile. Se evaluó presencia y ubicación del foramen, sexo, temporalidad y rango etáreo para cada muestra incluida. El FH se presentó en un 77,78% de los temporales, siendo 47,62% restos masculinos, 28,57% femeninos y 23,81% de sexo indeterminado. La totalidad de los restos de niños y subadultos presentaron FH, mientras que en adultos su expresión disminuye hasta un 68,42%. La ubicación fue un 38,10% en cuadrante inferomedial, 33,33% superolateral, 23,81% superomedial, 4,71% central. No se encontraron FH de ubicación inferolateral. El único temporal observable del período 10.000 AP (antes del presente, 1950) presentó FH, mientras que, en el período 7.000 AP se presentó en 6/7 temporales y en 14/19 temporales del período 1.000 AP. Los datos aportados complementan el conocimiento anatómico del proceso de osificación del hueso timpánico y la expresión de la dehiscencia timpánica como rasgo morfológico menor desde el estudio de poblaciones arqueológicas.

SUMMARY: The tympanic dehiscence or Foramen of Huschke (FH) is considered a transient minor, hypostosic, non-stochastic cranial feature, located in the tympanic plate of the temporal bone. Its expression is considered physiological until the age of five, and its presence is constant after that. This characteristic is seldom mentioned in anatomical literature since it is infrequent in modern populations. However, there is a difference when archaeological populations are studied. The purpose of this study is to describe the expression of the Huschke foramen in an archaeological population of central Chile. For this analysis, 27 temporal bones were obtained from human skeletal remains of the Tutuquén Cemetery Archaeological Monument. Presence and location of the foramen, sex, time period and age range were evaluated for each sample. The FH occurred in 77.78% of the temporal bones, with 47.62% male, 28.57% female and 23.81% of undetermined sex. All children and subadults presented FH, while in adults it decreased to 68.42%. The location was 38.10% in the inferomedial quadrant, 33.33 % superolateral, 23.81% superomedial, 4.71% central, and no FH was found at the inferolateral position. The only temporal bone identified in the 10,000 BP (before the present 1950) presented FH, while in the 7,000 BP period, it presented in 6/7 temporal bones and in the 1000 BP period, it was found in 14/ 19 temporal bones. The data provided complements anatomical knowledge of the tympanic bone ossification process, and in archaeological population studies, tympanic dehiscence presents as a lesser morphological characteristic.

Does tranexamic acid improve intra-operative visualisation in endoscopic ear surgery? A double-blind, randomised, controlled trial.

OBJECTIVE: To assess the effect of tranexamic acid on intra-operative bleeding and surgical field visualisation. METHODS: Fifty patients undergoing various endoscopic ear surgical procedures, including endoscopic tympanoplasty, endoscopic atticotomy or mastoidectomy, endoscopic ossiculoplasty, and endoscopic stapedotomy, were randomly assigned to: a study group that received tranexamic acid or a control group which received normal saline. The intra-operative bleeding and operative field visualisation was graded using the Das and Mitra endoscopic ear surgery bleeding and field visibility score, which was separately analysed for the external auditory canal and the middle ear. RESULTS: The Das and Mitra score was better (p < 0.05) in the group that received tranexamic acid as a haemostat when working in the external auditory canal; with respect to the middle ear, no statistically significant difference was found between the two agents. Mean values for mean arterial pressure, heart rate and surgical time were comparable in both groups, with no statistically significant differences. CONCLUSION: Tranexamic acid appears to be an effective haemostat in endoscopic ear surgery, thus improving surgical field visualisation, especially during manipulation of the external auditory canal soft tissues.

Surgically-Relevant Anatomy of the External Auditory Canal Bulge and Scutum.

HYPOTHESIS: Anatomic study of the external auditory canal's (EAC) anterior bulge, scutum, and ossicular chain will generate knowledge applicable to safe ear surgery and instrument design. BACKGROUND: The EAC contains two structures that obscure view of the middle ear: the anterior bulge and the scutum. The dimensions of these structures and their relationships to the ossicular chain have not been previously described. METHODS: Cadaveric temporal bones underwent computed tomography scanning, and three-dimensional reconstructions were created. Dimensions and angles of the EAC, its anterior bulge and scutum were measured. Distances to ossicular landmarks and the facial nerve were examined. RESULTS: The anterior EAC had a swan-neck shape. The thinnest portion was located medially and correlated with the canal thickness at the anterior bulge. However the thickness of the anterior bulge was not correlated with its angulation. The scutum averaged 3.8 mm long with a base thickness of 2.3 mm and a mean tip angle of 33 degrees. The short process of the incus was significantly closer to the scutum than other ossicular landmarks. CONCLUSION: Prominent anterior canal bulges are formed by posterior temporomandibular joints, not thicker bone. The scutum has asymmetric distances to various portions of the ossicles with the incus short process sometimes as close as 0.2 mm, placing it at risk of injury.

Clinical benefit of wideband-tympanometry: a pediatric audiology clinical study.

PURPOSE: Wideband-tympanometry (WBT) could give more informative data about the tympanic condition than the conventional tympanometry. In the actual literature, the clinical profit of wideband-tympanometry in pediatric audiological settings is not well evaluated. The aim of this study was to analyze the additional clinical benefit. METHODS: 150 children (281 ears) with normal hearing, at the age from 11 days up to 14;10 years, checked with pure tone audiometry or auditory brainstem responses (ABR) participated in this retrospective study. We divided in four age ranges (≤ 6 month; > 6 month ≤ 3 years; > 3 years ≤ 11 years; > 11 years). All children were evaluated with ENT examination including ear microscopy, conventional 226-Hz or 1000-Hz tympanometry and WBT. Ear canal volumes were determined. RESULTS: Compared with literature data, our patients aged ≤ 3 years showed smaller mean ear canal volumes (≤ 4 ml). We found a good statistical correlation between the WBT-results and 1000-Hz tympanometry but a rare correlation between WBT-results and ear microscopic findings. In the patients with pathologic ear microscopic results in all groups of age, a significant reduction of WBT-absorbance in 1000 Hz and 2000 Hz was found. CONCLUSIONS: This study confirms that WBT collects additive data to detect the correct middle ear status. In pediatric audiology, WBT is an additional useful method to value middle ear problems and to analyze the character of infantile hearing loss. Standard guidelines for the interpretation of the pediatric population are needed. Hence, it will be necessary to determine these findings in a larger number of infantile ears.

Feasibility of High-Resolution Computed Tomography Imaging for Obtaining Ear Impressions for Hearing Aid Fitting.

OBJECTIVE: This study investigated the feasibility of obtaining ear impressions for hearing aids by using 3-dimensional high-resolution computed tomography (HRCT) images. STUDY DESIGN: Case series. SETTING: One referral tertiary center. SUBJECTS AND METHODS: Hearing-impaired adults who were fitted with 1 or 2 behind-the-ear hearing aid(s) and had undergone temporal bone HRCT for various ear pathologies were enrolled in this study. Earmolds were fabricated from the impressions obtained using the conventional ear canal silicone injection technique and the HRCT reconstructed technique. Outer ear canal resonance frequencies and amplitude in open ears and those measured with silicon and HRCT reconstructed earmolds were determined through real-ear gain measurements, including real-ear unaided gain (REUG) and real-ear occluded gain (REOG), for comparison. RESULTS: A total of 50 HRCT reconstructed earmolds were compared with 50 conventional silicon injection earmolds. The average value of open ear canal resonance amplitude (REUG) for each ear was 0.41 to 16.76 dB. No statistically significant difference in resonance amplitude (REOG) was observed between silicon and reconstructed earmolds (paired t test, P > .05). The mean insertion loss (REOG-REUG) at all frequencies also did not differ significantly between the two earmolds (paired t test, P > .05). CONCLUSION: According to our real-ear measurements, acoustic characteristics of the HRCT reconstructed earmolds were compatible with those of the silicone injection earmolds. Despite concerns about increased cost and radiation exposure, the HRCT reconstructed technique is a clinically useful and applicable method and can reduce potential safety complications for difficult cases.

Endoscopic classification of the external auditory canal for transcanal endoscopic ear surgery.

OBJECTIVE: Evaluation of an endoscopic anatomic classification of the external auditory canal (EAC) for transcanal endoscopic ear surgery. MATERIALS AND METHOD: The EAC Canal Endoscopic Scale (CES) was initially defined according to total or partial EAC narrowing on 0° transcanal endoscopy. A retrospective study was then conducted between September 2013 and March 2015 in a series of consecutive patients fulfilling the study inclusion criteria. RESULTS: A total of 83% of 5000 patients (10000 ears) were classified as CES 0: i.e., total visualization of the tympanic membrane. Various kinds of EAC narrowing were described. Results were comparable between right and left ears. CONCLUSIONS: 0° endoscopy provided total visualization of the tympanic membrane in most cases, thanks to its magnified lateral view. Preoperative CES classification allows use of angled endoscopes, curved instruments or drilling for canalplasty to be planned in the first step of transcanal endoscopic ear surgery.

Predictors of round window membrane visibility in pediatric cochlear implant surgery using temporal bone HRCT: A retrospective study.

OBJECTIVE: To predict round window membrane (RWM) visibility and electrode insertion sites using high-resolution computed tomography (HRCT) in pediatric cochlear implant surgery. MATERIALS AND METHODS: Sixty-two ears of 36 infants less than 1 year old were included in our study. Intraoperative RWM visibility was classified into three types corresponding to three different surgical approaches. Radiologic parameters were measured on preoperative axial temporal HRCT images and correlated with RWM visibility and surgical approaches. RESULTS: A significant correlation was found between the degree of RWM visibility and the following two parameters: 1) a line (lw) was drawn from the posterior margin of the RWM to the intersection point of the posterior wall of the external auditory canal (EAC) and mastoid cortex. Another line (lf) was drawn between the posterior margin of the RWM and the lateral margin of the FN. The angle between lw and lf was measured as angle A, P < 0.01, R2 = -0.809; 2) a line (lm) was drawn from the anterior to posterior margin of the RWM, and the angle between lm and lf was measured as angle B, P < 0.01, R2 = -0.850. A nonsignificant correlation was found between the degree of RWM visibility and the facial recess width, p > 0.05, R2 = -0.00015. CONCLUSION: RWM visibility showed a high correlation with the two angular measurements (angle A and angle B) and was associated with electrode insertion sites. In children less than one year old, surgeons can depend on those two parameters in predicting the RWM visibility.

The anatomical and radiological evaluation of the Vidian canal on cone-beam computed tomography images.

INTRODUCTION: The aim of this study is to explore the anatomy of the Vidian nerve to elucidate the appropriate surgical approach based on preoperative cone-beam computed tomography (CBCT) images. MATERIALS AND METHODS: The Vidian canal and its surrounding structures were morphometrically evaluated retrospectively in CBCT images of 400 cases by the Planmeca Romexis program. The types of the Vidian canal were determined and seven parameters were measured from the images. RESULTS: Three types of the Vidian canal according to the relationship with the sphenoid bone were found as follows: the Vidian canal totally protruded into the sphenoid sinus (19.75%), partially protruded into sphenoid sinus (44.37%) and embedded inside bony tissue of the body of sphenoid bone (35.87%). The position of the Vidian canal was medial (34.62%), on the same line (55.12%) and lateral (10.25%) to the medial plate of the pterygoid process. The distance between the Vidian canal and the vomerine crest, the mid-sagittal plane, the round foramen, the palatovaginal canal, and the superior wall of the sphenoid sinus, the length of the Vidian canal and the angle between the Vidian canal and the sagittal plane was found to be 16.69 ± 2.14, 13.80 ± 2.00, 8.88 ± 1.60, 5.83 ± 1.37, 23.98 ± 2.68, 13.29 ± 1.71 mm and 25.78° ± 3.68° in males, 14.62 ± 1.66, 11.43 ± 1.28, 8.51 ± 1.63, 5.78 ± 0.57, 22.37 ± 2.07, 12.91 ± 1.26 mm and 23.43° ± 3.07° in females, respectively. CONCLUSIONS: Our results may assist with proper treatment for surgical procedures around the Vidian canal with a high success rate and minimal complications. Therefore, the results obtained in this study contribute to the literature.

A Novel Noninvasive Patient-Specific Navigation Method for Orbital Reconstructive Surgery: A Phantom Study Using Patient Data.

BACKGROUND: The correction of orbital deformities is an ongoing challenge in maxillofacial surgery. Computer-assisted navigation can improve surgical outcomes. However, conventional registration methods for navigation are not appropriate for orbital reconstructive surgery. This study proposes an accurate, noninvasive, patient-specific navigation method and demonstrates its feasibility. METHODS: A noninvasive, patient-specific registration frame based on the external auditory canals and upper front teeth was designed using software developed in-house. A three-dimensional craniofacial model was segmented from patient computed tomographic data for the registration frame. A customized craniofacial phantom was also made using this three-dimensional model, with 20 embedded target points on the orbital model and 21 landmark points on the reference standard model. The proposed method was compared with two conventional registration methods: the dental splint-based method and the invasive marker frame-based method. Twenty trials were conducted for evaluation. Target registration error and surface registration error were computed to measure accuracy. RESULTS: The proposed method showed a target registration error of 1.05 ± 0.52 mm, with greater accuracy than conventional methods (dental splint, 2.10 ± 0.63 mm; invasive marker frame, 1.22 ± 0.46 mm). The proposed method yielded the best results for surface registration error, with 0.38 mm of deviation (dental splint, 0.82 mm; invasive marker frame, 0.60 mm). CONCLUSION: The proposed noninvasive patient-specific registration method demonstrated superior results for both target registration error and surface registration error compared with other conventional registration methods for computer-assisted navigation in orbital reconstructive surgery. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

External auditory canal: Inferior, posterior-inferior, and anterior canal wall overhangs.

OBJECTIVES: To characterize anatomic variants of the external ear canal (EAC), specifically canal wall overhangs. EAC overhangs are problematic since they obstruct the view of the tympanic membrane (TM) and middle ear, possibly creating diagnostic and surgical difficulties. METHODS: We reviewed pre-operative temporal bone CTs from children with cholesteatoma, and no history of EAC erosion or surgery. We measured the anterior canal wall overhang (ACOH), inferior (ICOH), and posterior-inferior (PICOH). A smaller angle means more EAC overhang. Angles >180° counted as 180° since they are non-obstructing. Analysis was performed between angular measurements and clinical and demographic data. RESULTS: 86 patients (88 ears total) were studied. Mean age was 8.3 years. Only obstructing angles were analyzed statistically (<180°). The ICOH was most severe and occurred in 72/88 (81.8%) ears with a mean of 145.9 ±â€¯12.8SD° (range 102-171°). ACOH occurred in 60/88 (68.2%) ears with a mean of 148.3 ±â€¯10.9SD° (range 120-169°). PICOH occurred in 59/88 (67%) ears with a mean of 150.4 ±â€¯9.2SD° (range 124-169°). Overall, ICOH was significantly more severe than PICOH (P = 0.026). ICOH had more Severe (142-102°) overhangs (27/88, 30.7%) than ACOH (17/88, 19.3%) or PICOH (11/88, 12.5%), but these were not significantly different. Analysis of clinical data showed that as the ICOH overhang became more severe, there was a history of significantly more (p = 0.039, r = -0.209) tympanostomy tubes placed. CONCLUSIONS: The greatest prevalence and severity of EAC overhang was the ICOH with a mean angle of 145.9°, compared with 148.3° and 150.4° for the ACOH and PICOH, respectively. This anatomic study demonstrates that ICOH and PICOH are prevalent anatomic variants and may possibly cause similar difficulties in otoscopic diagnosis and surgical TM and middle ear exposure as the well-known ACOH.

The Human Cochlear Aqueduct and Accessory Canals: a Micro-CT Analysis Using a 3D Reconstruction Paradigm.

OBJECTIVE: We sought to study the anatomic variations of the cochlear aqueduct and its accessory canals in human temporal bones using micro-CT and a 3D reconstruction paradigm. More knowledge about the anatomic variations of these structures, particularly at the basal turn of the cochlea and round window niche, may be important to better preserve residual hearing as well as the neural supply during cochlear implant surgery. METHODS: An archival collection of 30 human temporal bones underwent micro-CT and 3D reconstruction. A surface enhancement paradigm was applied. The application displays reconstructed slices as a 3D object with realistic 3D visualization of scanned objects. Virtual sectioning or "cropping" of the petrous bone presented subsequent areas. Thereby, the bony canals could be followed from inside the basal turn of cochlea and middle ear to the jugular foramen. RESULTS: The cochlear aqueduct was always paralleled by an accessory canal containing the inferior cochlear vein. It ran from the basal turn of the cochlea and exited laterally in the jugular foramen. In 70% of the cases, a secondary accessory canal was observed and it derived mostly from a depression or infundibulum located in the floor of the round window niche. This canal also exited in the jugular foramen. The secondary accessory canal occasionally anastomosed with the primary accessory canal suggesting that it contains a vein that drains middle ear blood to the cranial sinus. CONCLUSION: Micro-CT with 3D surface reconstruction paradigm offers new possibilities to study the topographic anatomy of minor details in the human inner ear. The technique creates simulated transparent "castings" of the labyrinth with a coinciding surface view through enhancement of contrast between boundaries. Accessory canals that drain blood from the cochlea, spiral ganglion, and middle ear could be characterized three-dimensionally.

[The topographical and anatomical characteristic of the anterior part of the external auditory passage and the tympanic cavity]. / Topografoanatomicheskaia kharakteristika perednego otdela naruzhnogo slukhovogo prokhoda i barabannoi polosti.

The objective of the present work was to overview the currently available literature data on microtopographic anatomy of the anterior portion of the middle ear and the external auditory passage. Manipulations on these structures during miringoplasty surgery appear to be the most difficult and laborious operations because this space is anatomically very narrow and curved; moreover, it contains the important intimate structures of the middle ear and is located very close to the temporomandibular joint. The knowledge of microsurgical anatomy of the anterior part of the middle ear and the external auditory passage is paramount in the context of the improvement of the professional skills of the surgeons. The current literature data provide a basis for the conclusion that many aspects of microsurgical anatomy of the anterior part of the tympanic cavity and the external auditory passage thus far remain poorly explored. This assertion is especially true as regards the relief of the mucous membrane overlying these structure and their supply with arterial blood. Further clarification of these aspects is needed.

The anatomic applicability of transcanal endoscopic ear surgery in children.

OBJECTIVE: The feasibility of TEES in dealing with pediatric middle ear disease is still under investigation. The goal of this study was to compare anatomical dimensions of the EAC between children and adults, and to analyze the anatomic applicability of TEES in children. METHODS: Forty pediatric (18 years old and younger) and 20 adult patients who received TB-HRCT to evaluate middle ear conditions were enrolled from December 2010 to December 2015. Dimensions including the diameters of the EAC orifice, isthmus and tympanic membrane annulus, the length of EAC, the height of the middle ear, and the angle between tympanic membrane and EAC axis were determined according to the TB-HRCT data. RESULTS: The diameters of the EAC orifice and isthmus and length of EAC in the pediatric patients were slightly smaller than those in the adult patients. The anatomical dimensions of middle ear were similar in both groups. Simple regression analysis indicated that the diameters of the EAC orifice and isthmus and the length of the EAC were positively correlated with the age of the pediatric patients. In the pediatric patients, 67 ears (83.75%) had an EAC isthmus diameter larger than 4 mm and are sufficient with a 3-mm endoscope manipulation. CONCLUSION: TEES is applicable for most pediatric patients using an endoscope with a diameter of 3 mm or smaller. With an appropriate endoscope and instruments, TEES is a safe and effective alternative to treat pediatric middle ear disease.

Preoperative evaluation of cochlear implantation through the round window membrane in the facial recess using high-resolution computed tomography.

PURPOSE: We evaluated the risk of cochlear implantation through the round window membrane in the facial recess through a preoperative analysis of the angle between the facial nerve-round window and the cranial midline using high-resolution temporal bone CT. METHODS: Temporal bone CT films of 176 patients with profound sensorineural hearing loss at our hospital from 2013 to 2015 were reviewed. The preoperative temporal bone CT scans of the patients were retrospectively analysed. The vertical distance (d value) from the leading edge of the facial nerve to the posterior wall of the external auditory canal and the angle (α value) between the line from the leading edge of the facial nerve to the midpoint of the round window membrane and the median sagittal line on the round window membrane plane were measured. Based on intraoperative observation, the round window membrane was divided into complete round window membrane exposure (group A), partial exposure (group B), and unexposed (group C) groups, and statistical analysis was performed. RESULTS: The α value could be effectively measured for all 176 patients (62.60 ± 7.12), and the d value could be effectively measured for 95 cases (5.53 ± 1.00). An analysis of the correlation between the α and d values of these 95 cases found a negative correlation. Of the 176 cases, one-way analysis of variance (ANOVA) showed that the differences among the groups were significant [P = 0.000 (< 0.05)]. CONCLUSION: The angle (α value) between the line connecting the leading edge of the facial nerve to the midpoint of the round window and the median sagittal line measured in preoperative CT scans was associated with the difficulty of intraoperatively exposing the round window membrane. When the α value was larger than a certain degree, the difficulty of exposing the round window membrane was increased. In such cases, the surgeon should fully expose the round window membrane during surgery, which could result decrease the likelihood of complications.

Aural exostoses (surfer's ear) provide vital fossil evidence of an aquatic phase in Man's early evolution.

For over a century, otolaryngologists have recognised the condition of aural exostoses, but their significance and aetiology remains obscure, although they tend to be associated with frequent swimming and cold water immersion of the auditory canal. The fact that this condition is usually bilateral is predictable since both ears are immersed in water. However, why do exostoses only grow in swimmers and why do they grow in the deep bony meatus at two or three constant sites? Furthermore, from an evolutionary point of view, what is or was the purpose and function of these rather incongruous protrusions? In recent decades, paleoanthropological evidence has challenged ideas about early hominid evolution. In 1992 the senior author suggested that aural exostoses were evolved in early hominid Man for protection of the delicate tympanic membrane during swimming and diving by narrowing the ear canal in a similar fashion to other semiaquatic species. We now provide evidence for this theory and propose an aetiological explanation for the formation of exostoses.

Evaluation of a low-fidelity ear surgery simulator in a low-resource setting.

OBJECTIVE: The provision of healthcare education in developing countries is a complex problem that simulation has the potential to help. This study aimed to evaluate the effectiveness of a low-cost ear surgery simulator, the Ear Trainer. METHODS: The Ear Trainer was assessed in two low-resource environments in Cambodia and Uganda. Participants were video-recorded performing four specific middle-ear procedures, and blindly scored using a validated measurement tool. Face validity, construct validity and objective learning were assessed. RESULTS: The Ear Trainer provides a realistic representation of the ear. Construct validity assessment confirmed that experts performed better than novices. Participants displayed improvement in all tasks except foreign body removal, likely because of a ceiling effect. CONCLUSION: This study validates the Ear Trainer as a useful training tool for otological microsurgical skills in developing world settings.

3D-printed pediatric endoscopic ear surgery simulator for surgical training.

INTRODUCTION: Surgical simulators are designed to improve operative skills and patient safety. Transcanal Endoscopic Ear Surgery (TEES) is a relatively new surgical approach with a slow learning curve due to one-handed dissection. A reusable and customizable 3-dimensional (3D)-printed endoscopic ear surgery simulator may facilitate the development of surgical skills with high fidelity and low cost. Herein, we aim to design, fabricate, and test a low-cost and reusable 3D-printed TEES simulator. METHODS: The TEES simulator was designed in computer-aided design (CAD) software using anatomic measurements taken from anthropometric studies. Cross sections from external auditory canal samples were traced as vectors and serially combined into a mesh construct. A modified tympanic cavity with a modular testing platform for simulator tasks was incorporated. Components were fabricated using calcium sulfate hemihydrate powder and multiple colored infiltrants via a commercial inkjet 3D-printing service. RESULTS: All components of a left-sided ear were printed to scale. Six right-handed trainees completed three trials each. Mean trial time (n = 3) ranged from 23.03 to 62.77 s using the dominant hand for all dissection. Statistically significant differences between first and last completion time with the dominant hand (p < 0.05) and average completion time for junior and senior residents (p < 0.05) suggest construct validity. CONCLUSIONS: A 3D-printed simulator is feasible for TEES simulation. Otolaryngology training programs with access to a 3D printer may readily fabricate a TEES simulator, resulting in inexpensive yet high-fidelity surgical simulation.