Relevant anatomical details in rats regarding otologic research / Detalles anatómicos relevantes en ratas para la investigación otológica

SUMMARY: The objective of the study was to provide a detailed anatomical description of the rat's ear anatomy that will prove insightful to different experimental otologic surgical procedures regardless of scope. Three male Wistar rats were enrolled in the study. Candidates were screened for systemic and otologic pathology. External ear canal endoscopy was carried out with a 30˚ rigid endoscope through an image capture system. Middle ear anatomical elements were analyzed under stereomicroscopy. 3D computer tomography image reconstruction was realized with a micro-CT to describe the anatomy. Image data from all three rats were analyzed. Anatomical annotations and surgical exposure recommendations were added for key elements. The most relevant images from all three rats were selected for representation. Detailed visualization of the structural elements of the tympanic cavity were clearly visible: promontory, round window, stapedial artery, stapes, incus, and tympanic membrane were all constant findings. We describe a step wise ventral surgical approach of the middle and inner ear for which we found that the clavotrapezius muscle was a reliable landmark. For the transtympanic approach the endoscopic transcanal access was an easy and reliable method for which a detailed anatomical representation was depicted. Further, anatomical similarities to humans were observed by stereomicroscopy and Micro-CT imaging reiterating that the rat model is suitable for otologic research. The endoscopic approach to the tympanic membrane is comfortable and less expensive than a microscope. The tendon of the clavotrapezius muscle can be a reliable landmark for discovering the tympanic bulla when considering a ventral approach. 3D Micro-CT reconstruction allows intact evaluation of the samples, simultaneously being a diagnostic and also a learning tool.

RESUMEN: El objetivo de este trabajo fue proporcionar una descripción anatómica detallada de la anatomía del órgano vestíbulococlear de la rata que resultará útil para diferentes procedimientos quirúrgicos otológicos experimentales, independientemente del alcance. En el estudio se usaron tres ratas Wistar macho. Los ejemplares fueron evaluados por patología sistémica y otológica. La endoscopía del meato acústico externo se realizó con un endoscopio rígido de 30˚ a través de un sistema de captura de imágenes. Los elementos anatómicos del oído medio se analizaron bajo estereomicroscopía. La reconstrucción de la imagen de tomografía computarizada en 3D se realizó con un micro-CT para describir la anatomía. Se analizaron los datos de imagen de las tres ratas. Se agregaron anotaciones anatómicas y recomendaciones de exposición quirúrgica para elementos clave. Las imágenes más relevantes de las tres ratas fueron seleccionadas para su representación. La visualización detallada de los elementos estructurales de la cavidad timpánica era claramente visible: promontorio timpánico, ventana coclear, arteria estapedial, estapedio, yunque y membrana timpánica eran hallazgos constantes. Describimos un abordaje quirúrgico ventral escalonado del oído medio e interno para el cual encontramos que el músculo clavotrapecio era un punto de referencia confiable. Para el abordaje transtimpánico, el acceso transcanal endoscópico fue un método fácil y confiable para el cual se describió una representación anatómica detallada. Además, se observaron similitudes anatómicas con los humanos mediante estereomicroscopía e imágenes Micro-CT, lo que reitera que el modelo de rata es adecuado para la investigación otológica. El abordaje endoscópico de la membrana timpánica es cómodo y menos costoso que un microscopio. El tendón del músculo clavotrapecio puede ser un punto de referencia fiable para descubrir la bulla timpánica cuando se considera un abordaje ventral. La reconstrucción 3D Micro- CT permite la evaluación intacta de las muestras, siendo simultáneamente una herramienta de diagnóstico y también de aprendizaje.

Inner ear salivary gland choristoma extending to the middle ear with congenital profound hearing loss and facial palsy: a case report.

BACKGROUND: Salivary gland choristoma (SGCh) is a rare benign tumor reported in several unusual sites, such as the gastrointestinal tract, the optic nerve, and the internal auditory canal, but never reported in the inner ear. CASE PRESENTATION: An 8-year-old girl with a history of left profound congenital hearing loss presented to us with ipsilateral progressive severe facial nerve palsy (House-Brackmann Grade VI). The left tympanic membrane was swollen with a pulsatile tumor. Radiological investigations revealed a multilocular tumor in the inner ear extending into the middle ear and internal auditory canal (IAC). We performed a partial resection of the tumor by transmastoid approach to preserve the anatomical structure of the facial nerve. The tumor was pathologically diagnosed as SGCh. Two years after surgery, her facial function recovered to House-Brackmann Grade II and the residual tumor did not show regrowth on MRI. CONCLUSIONS: Although the natural course of this rare tumor is unknown, a partial resection is an acceptable treatment procedure when functional recovery of the facial nerve is anticipated.

The use of near infrared fluorescence imaging with indocyanine green for vascular visualization in caudal auricular flaps in two cats.

OBJECTIVES: To describe the use of near infrared fluorescence (NIRF) imaging with indocyanine green (ICG) for vascular visualization in two caudal auricular axial pattern flaps (APF). ANIMALS: Two client-owned cats with upper eyelid masses. STUDY DESIGN: Clinical case report. METHODS: Wide surgical excision with enucleation was performed by using a caudal auricular APF for closure. Flap margins and perforating artery location were approximated with anatomical landmarks. The caudal auricular artery origin was then visualized percutaneously by using an exoscope with NIRF camera and light source after a single 2.5-mg dose of IV ICG. Margins were adjusted as required. The flaps were routinely elevated with continued intraoperative visualization of the artery and rotated to complete closure. RESULTS: After IV ICG administration, fluorescence was initially visualized after 15 to 18 seconds and remained visible for up to 26 minutes. The achieved visualization led to flap margin adjustments in cat 1. Both cats recovered with minimal flap congestion, excellent hair regrowth, and no long-term complications (>186 days). Cat 1 experienced 100% flap survival. Cat 2 experienced 10% partial thickness flap necrosis, but revision was not required, and the flap was healed at recheck 85 days postoperatively. CONCLUSION: The use of ICG for APF vessel visualization prior to and during flap elevation resulted in transcutaneous visualization of the perforating vessel and improved awareness of vessel location intraoperatively. These two cats experienced excellent flap survival without major complications. This report highlights the potential benefits of ICG NIRF in APF for animals undergoing reconstructive surgery.

Is There a Coexistence of Peritemporal Wormian Bones and Congenital Aural Atresia?

In this study, the percent of wormian bones in congenital aural atresia group was higher than healthy group, when tested by the Fisher exact test, there appeared to be no significant statistical difference. However, in congenital aural atresia surgery, surgical manipulation can dislodge these bones causing injury to the surrounding structures. Therefore, the radiologists should report the presence of wormian bones in the peritemporal area.

High-resolution computed tomography evaluation of congenital aural atresia - how useful is this?

OBJECTIVE: To depict various temporal bone abnormalities on high-resolution computed tomography in congenital aural atresia patients, and correlate these findings with auditory function test results and microtia subgroup. METHODS: Forty patients (56 ears) with congenital malformation of the auricle and/or external auditory canal were evaluated. Auricles were graded according to Marx's classification, divided into subgroups of minor (grades I and II) and major (III and IV) microtia. Other associated anomalies of the external auditory canal, tympanic cavity, ossicular status, oval and round windows, facial nerve, and inner ear were evaluated. RESULTS: Minor and major microtia were observed in 53.6 and 46.4 per cent of ears respectively. Mean hearing levels were 62.47 and 62.37 dB respectively (p = 0.98). The malleus was the most commonly dysplastic ossicle (73.3 vs 80.8 per cent of ears respectively, p = 0.53). Facial nerve (mastoid segment) abnormalities were associated (p = 0.04) with microtia subgroup (80 vs 100 per cent in minor vs major subgroups). CONCLUSION: Microtia grade was not significantly associated with mean hearing levels or other ear malformations, except for external auditory canal and facial nerve (mastoid segment) anomalies. High-resolution computed tomography is essential in congenital aural atresia, before management strategy is decided.

Location of the stapedius muscle with reference to the facial nerve in patients with unilateral congenital aural atresia: implication for active middle ear implants surgery.

Background: Detailed investigations of the stapedial muscle (SM) in congenital aural atresia (CAA) patients have yet to be adequately conducted.Objectives: To assess image variations in the mastoid segment of the facial nerve (FN) and SM in CAA.Materials and methods: A total of nine patients comprising of 9 ears with unilateral CAA were studied. The courses of the FN and SM were evaluated from the basic point to 1 mm intervals between the mastoid portion of FN, and measured from the mean X and Y values in each group.Results: The atresia side of FN among the Y values showed significant differences compared to the contralateral side. In terms of the SM, there were no significant differences in both the X and Y values. The stapedial muscle of the CAA patients was located medially to the FN. Conversely, the distance from the PSC to the FN revealed no significant differences with regard to the X and Y values for each group.Conclusion: The current observations revealed that the SM is located more posterior to the FN in CAA patients, and this is mainly attributed to the laterally and anteriorly displaced FN.

2D browsing software and 3D PDF of canine ear based on real color sectioned images / Software de navegación 2D y PDF en 3D del oído canino basado en imágenes seccionadas en color real

Dog ear is very important because of disease vulnerability. Therefore, gross anatomy and sectional anatomy on CT and MRI of the dog ear should be mastered by veterinarian. The purpose of this research was to present the digital atlases which high quality sectioned images and 3D models of detailed structures of dog ear could be displayed freely. In the sectioned images of a female beagle, ear structures were reconstructed by surface modeling to make 3D models. The sectioned images and 3D models were put into the browsing software and PDF file, respectively. Using the browsing software and the PDF file, gross and radiological anatomy of dog ear could be learned easily and accurately. The auditory tube of a dog was placed anterior to the tympanic cavity unlike human. The tensor tympani muscle of a dog was connected to the dorsal wall of the tympanic cavity with the malleus. No remarkable difference in the auditory ossicles, semicircular ducts, facial nerve, and endolymphatic duct was observed between dogs and humans. The software and the PDF file will be provided to other researchers freely to help contribute to veterinary research and education.

La oreja del perro es importante debido a la vulnerabilidad de enfermedad. Por lo tanto, el veterinario debe conocer plenamente la anatomía macroscópica y la anatomía seccional en la TC y la RM del oído del perro. El objetivo de esta investigación fue presentar los atlas digitales que podían mostrar imágenes seccionadas de alta calidad y modelos 3D de estructuras detalladas de orejas de perro. En las imágenes seccionadas de una hembra Beagle, las estructuras de las orejas se reconstruyeron mediante modelado de superficie con el objetivo de crear modelos 3D. Las imágenes seccionadas y los modelos 3D se colocaron en un software de navegación y un archivo PDF. El uso de software de navegación y el archivo PDF permiten un aprendizaje fácil y preciso de la anatomía macroscópica y radiológica de la oreja de perro. El músculo tensor del tímpano de un perro estaba conectado a la pared dorsal de la cavidad timpánica con el martillo. No se observaron diferencias notables en los huesecillos auditivos, los conductos semicirculares, el nervio facial y el conducto endolinfático entre perros y humanos. El software y el archivo PDF estarán disponibles libremente para los investigadores para ayudar en la investigación y educación veterinaria.

Endoscopic-Assisted Cochlear Implantation in Children with Malformed Ears.

OBJECTIVE: Complex middle and inner ear malformations are considered an important limitation for cochlear implant (CI) with traditional microscopic techniques. The aim of the present study is to describe the results of the endoscopic-assisted CI procedure in children with malformed ears. STUDY DESIGN: Case series with chart review of consecutive patients. SETTING: Two tertiary referral centers: University Hospital of Verona and University Hospital of Modena, Italy. SUBJECTS AND METHODS: In total, 25 children underwent endoscopic-assisted cochlear implantation between January 2013 and January 2018. The audiologic and neuroradiologic assessment showed profound hearing loss and malformation of the middle and inner ear in all children. A complete review of anatomic features, surgical results, and audiologic outcomes was performed. The surgical technique is described step-by-step, and the outcomes are detailed. RESULTS: All patients (mean age, 3.6 years; range, 2.8-9 years) underwent a transattical/endoscopic-assisted CI procedure. All children showed varying degrees of auditory benefit, as measured by routine audiometry, speech perception tests, and Categories of Auditory Performance scores (mean, 6). No immediate or late postoperative complications were noted. CONCLUSION: The endoscopic-assisted approach proved to be successful in cochlear implantation. The direct visualization and magnification allow (1) exploration of the tympanic cavity; (2) confirmation of all anatomic features, with strict control of the course of the facial nerve, round window area, and inner ear; and (3) performance of the cochleostomy with adequate insertion of the array.

Visualizing Interactions of Circulating Tumor Cell and Dendritic Cell in the Blood Circulation Using In Vivo Imaging Flow Cytometry.

OBJECTIVE: Visualizing cell interactions in blood circulation is of great importance in studies of anticancer immunotherapy or drugs. However, the lack of a suitable imaging system hampers progress in this field. METHODS: In this work, we built a dual-channel in vivo imaging flow cytometer to visualize the interactions of circulating tumor cells (CTCs) and dendritic cells (DCs) simultaneously in the bloodstream. Two artificial neural networks were trained to identify blood vessels and cells in the acquired images. RESULTS AND CONCLUSION: Using this technique, single CTCs and CTC clusters were readily distinguished by their morphology. Interactions of CTCs and DCs were identified, while their moving velocities were analyzed. The CTC-DC clusters moved at a slower velocity than that of single CTCs or DCs. This may provide new insights into tumor metastasis and blood rheology. SIGNIFICANCE: This in vivo imaging flow cytometry system holds great potential for assessing the efficiency of targeting CTCs with anticancer immune cells or drugs.

Posterior Distraction First or Fronto-Orbital Advancement First for Severe Syndromic Craniosynostosis.

PURPOSE: Posterior calvarial vault expansion using distraction osteogenesis is performed for syndromic craniosynostosis as the first choice. This procedure allows far greater intracranial volume than fronto-orbital advancement (FOA). This study aimed to determine the most suitable timing of posterior distraction or FOA to sufficiently increase the intracranial volume and remodel the skull shape. PATIENTS AND METHODS: From 2014 to 2017, the authors performed posterior distraction in 13 patients with syndromic craniosynostosis. Data on premature suture fusion, age at first visit, age at surgery, skull thickness, and complications were collected. RESULTS: Five patients underwent posterior distraction at approximately 12 months of age and had no complications, including cerebrospinal fluid leakage or gull wing deformity. However, during the waiting period for the operation, the skull deformity continues to extend upward (turribrachycephaly). To prevent progress of the skull deformity, the authors performed the operation at approximately 6 months of age in 7 patients. However, in 3 of 7 patients whose lambdoid sutures were opening, gull wing deformity occurred. From these results, in a patient with severe Beare-Stevenson syndrome, the authors performed FOA first at 5 months of age, followed by posterior distraction at 12 months of age, and achieved favorable results. CONCLUSIONS: Treatment patterns are patient specific and should be tailored to premature suture fusion, specific skull deformity, and required intracranial volume of each patient.

Imaging of Pediatric Hearing Loss.

Temporal bone high-resolution computed tomography (HRCT) and magnetic resonance (MR) imaging are valuable tools in the evaluation of pediatric hearing loss. Computed tomography is important in the evaluation of pediatric conductive hearing loss and is the imaging modality of choice for evaluation of osseous abnormalities. MR imaging is the modality of choice for evaluation of sensorineural hearing loss. A broad spectrum of imaging findings can be seen with hearing loss in children. HRCT and MR imaging provide complementary information and are often used in conjunction in the preoperative evaluation of pediatric candidates for cochlear implantation.

Common Otologic Surgical Procedures: Clinical Decision-Making Pearls and the Role of Imaging.

Neuro-otologists rely on the expertise and judgment of a skilled neuroradiologist to identify radiographic abnormalities in the complicated regional anatomy of the temporal bone and middle and posterior fossa, and more importantly, to alert the surgeon to potential operative pitfalls. This article highlights some of the common otologic surgical procedures that stress this important dynamic. The surgical perspective on quick and effective clinical decision-making pearls to keep in mind during a thorough radiographic analysis of the ear and lateral skull base is presented.

Surgeon oriented preoperative radiologic evaluation in cochlear implantation - our experience with a proposed checklist

Introduction: Preoperative temporal bone imaging studies have been routinely performed prior to cochlear implantation. Radiologists need to report these examinations with special focus on the surgeon's expectations. Objectives: To provide a basic structured format, in the form of a checklist, for reporting preoperative computed tomography (CT) and to its clinical impact on operative findings. Methods: The preoperative temporal bone CT scans of 47 patients were analyzed and reported according to the proposed checklist. Intraoperative assessment of mastoidectomy, posterior tympanotomy and round window access was done by the surgeon in a blinded fashion and were correlated with the radiological findings to assess its significance. Results: The proposed radiological checklist was reliable in assessing operative difficulty during cochlear implantation. Contracted mastoid and lower tegmen position were associated with a greater difficulty of the cortical mastoidectomy. Presence of an air cell around the facial nerve (FN) was predictive of easier facial recess access exposure. Facial nerve location and posterior external auditory canal (EAC) wall inclination were predictive of difficult round window (RW) accessibility. Conclusion: Certain parameters on the preoperative temporal bone CT scan may be useful in predicting potential difficulties encountered during the key steps involved in cochlear implant surgery (AU)

Proposal of a Budget-Friendly Camera Holder for Endoscopic Ear Surgery.

Endoscopic ear surgery (EES) is increasingly a preferred technique in otologic society. It offers excellent visualization of the anatomical structures directly and behind the corners with variable angled telescopes. It also provides reduced operative morbidity due to being able to perform surgical interventions with less invasive approaches. Operative preparation and setup time and cost of endoscopy system are less expensive compared with surgical microscopes. On the other hand, the main disadvantage of EES is that the surgery has to be performed with 1 single hand. It is certainly restrictive for an ear surgeon who has been operating with 2 hands under otologic microscopic views for years and certainly requires a learning period and perseverance. Holding the endoscope by a second surgeon is not executable because of insufficient surgical space.Endoscope/camera holders have been developed for those who need the comfort and convenience afforded by double-handed microscopic ear surgery. An ideal endoscope holder should be easy-to-set up, easily controlled, providing a variety of angled views, allowing the surgeon to operate with 2 hands and, budget-friendly. In this article, a commercially available 11-inch magic arm camera holder is proposed by the authors to be used in EES due to its versatile, convenient, and budget-friendly features. It allows 2-handed EES through existing technology and is affordable for surgeons looking for a low-cost and practical solution.

Preoperative evaluation and intraoperative protection of the facial nerve in congenital aural atresia.

We conducted a prospective study to assess the value of high-resolution computed tomography (HRCT) in identifying facial nerve variations in patients with congenital aural atresia and to determine how they affect otologic reconstruction surgery. Our study population was made up of 65 patients (69 ears) aged 6 to 22 years (mean: 13.7) without regard to sex. They were classified into three groups according to their scores on the Jahrsdoerfer grading scale: 46 ears scored 8 or more, 18 had a score of 6 or 7, and 5 scored 5 or less. The course of each facial nerve as determined intraoperatively was compared with the preoperative HRCT findings. HRCT revealed that in most of the facial nerves, the tympanic segments overlapped the oval window partly or completely; this was confirmed by surgical findings in most cases. Three of the 69 facial nerves (4.3%) were bifurcated. It is interesting that in 1 ear in which the facial nerve completely covered the oval window, the angle of the second genu was acute, exhibiting a "sharp turn." We conclude that HRCT is undoubtedly of value in identifying the course of the facial nerve and is of critical importance in helping surgeons make correct decisions in otologic reconstruction surgery.

Three-dimensional assessment of the temporal bone and mandible deformations in patients with congenital aural atresia.

OBJECTIVE: To investigate the deformations of temporal bone and mandible combined with congenital aural atresia. METHODS: A total of 158 patients with congenital aural atresia were included in the study. The raw CT data of the temporal bone was imported into MIMICS v 12 and threshold dissection, region growing and three-dimensional (3D) calculation were used to calculate 3D models. The 3D characteristics of the temporal bone and upper part of mandible were assessed. RESULTS: The tympanic part of the temporal bone was all undeveloped. Of all the patients included, 14 patients were found to have severe maxillofacial malformations. Among them, 2 cases have floating arch, 4 cases have interrupted arch, 5 cases have mandibular processes hypoplasia and 3 cases have interrupted arch combined with severe maxillary malformation. Ten of the 14 patients were suffered from dysplasia of the mastoid part of the temporal bone as well. CONCLUSION: Maxillofacial malformations may sometimes coexist with congenital aural atresia. Otolaryngologists should not neglect the coexisted maxillofacial malformations and give timely referral to maxillofacial surgeons.

Anatomical measurement of the ossicles in patients with congenital aural atresia and stenosis.

OBJECTIVES: Our aims were to measure and compare anatomical parameters of the ossicles in normal, congenital aural stenosis (CAS), and congenital aural atresia (CAA) ears. METHODS: This retrospective study was performed using three-dimensional reconstructed images derived from computed tomography scans of 20 normal subjects, 20 CAS patients, and 20 CAA patients. RESULTS: The lengths of the malleus handle and long process of the incus were greater in normal ears than in CAS and CAA ears (all P < 0.05). The angles of the incudostapedial joint and between the short and long processes of the incus were smaller in normal ears than in CAS and CAA ears (all P < 0.05). There were no significant differences in the positions of the malleus head and incudomalleolar joint, the size of the malleus head, the length of the short process of the incus, or the angle of the incudomalleolar joint (P > 0.05). CONCLUSIONS: Anatomical parameters of the lower part, but not of the upper part, of the ossicular chain in CAS and CAA ears differed from those in normal ears. Different branchial arch origins of the upper and lower parts of the ossicular chain may explain these findings. Dysplasia of the second arch, which develops into the lower part of the ossicular chain, may contribute to ossicular malformation in CAA and CAS. Accurate radiographic measurement of malformed ossicles may be useful for reconstructive surgery of CAA and CAS using the patient's native ossicular chain and for choosing an appropriate place for active middle ear implants.

Predictive Factors for Hearing Outcomes After Canaloplasty in Patients With Congenital Aural Atresia.

OBJECTIVE: The aim of this study was to determine the most important factors in preoperative imaging, including components of Jahrsdoefer score (J score), and favorable prognostic factors for postoperative hearing results after canaloplasty for congenital aural atresia. STUDY DESIGN: Retrospective review of medical records. SETTING, PATIENTS, INTERVENTION, MAIN OUTCOME MEASURE: One hundred eight patients who underwent canaloplasty by a single surgeon between January 2011 and July 2014 were included. The influence of the following factors on the success for restoring of hearing was evaluated by univariable and multivariable logistic regression analyses: sex, atretic side, total J score, each component of Jahrsdoerfer grading scale, incudostapedial joint angle, inferior displacement of the tegmen, middle ear height, and inner ear anomaly. RESULTS: Successful hearing outcome was defined as postoperative air conduction ≤40 dB at 3 months after surgery, and it was achieved in 74 of 108 ears (70.5%). Univariable analysis revealed that the total J score, course of the facial nerve, presence of the malleus-incus complex, pneumatization of the mastoid, and middle ear height were significant as favorable predictive factors. Multivariable analysis revealed that middle ear height and inferior displacement of the tegmen were significant as favorable predictive factors. Inferior displacement of the tegmen was the most significant factor by the stepwise selection method in the final model. CONCLUSION: Middle ear height and inferior displacement of the tegmen are useful factors in predicting favorable hearing results after canaloplasty for congenital aural atresia. These factors might have a useful prognostic value supplementary to the J score.