Assessment of Middle Ear Anatomy Teaching Methodologies Using Microscopy versus Endoscopy: A Randomized Comparative Study.

Teaching methodologies for the anatomy of the middle ear have not been investigated greatly due to the middle ear's highly complex structure and hidden location inside of the temporal bone. The aim of this randomized study was to quantitatively compare the suitability of using microscope- and endoscope-based methods for teaching the anatomy of the middle ear. We hypothesize that the endoscopic approach will be more efficient compared to the microscopic approach. To answer the study questions, 33 sixth-year medical students, residents and otorhinolaryngology specialists were randomized either into the endoscopy or the microscopy group. Their anatomical knowledge was assessed using a structured anatomical knowledge test before and after each session. Each participant received tutoring on a human cadaveric specimen using one of the two methods. They then performed a hands-on dissection. After 2-4 weeks, the same educational curriculum was repeated using the other technique. The mean gains in anatomical knowledge for the specialists, residents, and medical students were +19.0%, +34.6%, and +23.4%, respectively. Multivariate analyses identified a statistically significant increase in performance for the endoscopic method compared to the microscopic technique (P < 0.001). For the recall of anatomical structures during dissection, the endoscopic method outperformed the microscopic technique independently of the randomization or the prior training level of the attendees (P < 0.001). In conclusion, the endoscopic approach to middle ear anatomy education is associated to an improved gain in knowledge as compared to the microscopic approach. The participants subjectively preferred the endoscope for educational purposes

Accuracy and feasibility of a dedicated image guidance solution for endoscopic lateral skull base surgery.

OBJECTIVE We aimed to design, build and validate a surgical navigation system which fulfills the accuracy requirements for surgical procedures on the ear and the lateral skull base, and which integrates with the endoscopic workflow and operating room setup. MATERIALS AND METHODS The navigation system consists of portable tablet computer (iPad Pro, Apple Computer, USA) and an optical tracking system (Cambar B1, Axios3D, Germany), both connected via a wireless Bluetooth link and attached directly to the OR table. Active optical tracking references are rigidly fixed to both the patient and surgical tools. Software to support image import, registration and 2D/3D visualization has been developed. Two models were used for targeting accuracy assessment: a technical phantom model and an ex vivo temporal bone model. Additionally, workflow integration and usability of the navigation system during endoscopic lateral skull base procedures was investigated in ex vivo experiments on 12 sides of cadaver head specimens. RESULTS The accuracy experiments revealed a target registration error in the technical phantom model of 0.20 ± 0.10 mm (n = 36) and during the ex vivo assessment of 0.28 ± 0.10 mm (n = 21). Navigation was successfully carried out in n = 36 procedures (infracochlear, suprageniculate and transpromontorial approach), with navigated instruments usable without interference with the endoscope. The system aided in the successful and accurate identification of vital anatomical structures. CONCLUSIONS Useful surgical navigation is, to a large extent, a result of sufficiently accurate tracking technology. We have demonstrated sufficient accuracy and a potentially suitable integration for surgical application within endoscopic lateral skull base procedures

Acquisition of basic ear surgery skills: a randomized comparison between endoscopic and microscopic techniques.

BACKGROUND Endoscopic ear surgery is gaining increasing popularity and has an important impact on teaching middle ear anatomy and basic surgical skills among residents and fellows. Due to the wide-angled views offered, the approach significantly differs from the established microscopic technique. This randomized study compares the acquisition of basic ear-surgery skills using the endoscopic and microscopic technique under standardized conditions. We aim to investigate the required surgical times, attempts and accidental damages to surrounding structures (errors) in surgeons with different training levels. METHODS Final-year medical students (n = 9), residents (n = 14) and consultants (n = 10) from the Department of Otorhinolaryngology, Head and Neck Surgery at the University Hospital of Bern, Switzerland were enrolled in the present study. After randomization every participant had to complete a standard set of grasping and dissecting surgical tasks in a temporal bone model. After the first session the participants were crossed over to the other technique. RESULTS Time required for completion of the surgical tasks was similar for both techniques, but highly dependent on the training status. A significant increase in the number of damages to the ossicular chain was observed with the microscopic as compared to the endoscopic technique (p < 0.001). Moreover, students beginning with the endoscopic technique showed an overall significantly lower amount of time to complete the tasks (p = 0.04). From the subjective feedback a preference towards the endoscopic technique mainly in medical students was observed. CONCLUSIONS The endoscopic approach is useful and beneficial for teaching basic surgical skills, mainly by providing a reduction of damage to surrounding tissues with similar operating times for both techniques. Moreover, medical students performed significantly faster, when first taught in the endoscopic technique. Especially for young surgeons without previous training in ear surgery, the endoscope should be considered to improve surgical skills in the middle ear

Long-term functional outcome after laryngeal cancer treatment.

BACKGROUND The functional outcome after the treatment of laryngeal cancer is tightly related to the quality of life of affected patients. The aim of this study is to describe the long-term morbidity and functional outcomes associated with the different treatment modalities for laryngeal cancer. METHODS Retrospective chart review of 477 patients undergoing curatively intended treatment for laryngeal cancer at our tertiary referral center from 2001 to 2014: Details on patient and disease characteristics, diagnostics and treatment related functional outcomes were analyzed. RESULTS With a median follow-up of 51 months, the crude rate of functional larynx preservation was 74.6%. Radiotherapy +/- chemotherapy was the dominant treatment modality (n = 359-75.3%), whereas 24.7% (n = 118) underwent primary surgery, with 58.5% (69) receiving adjuvant treatment. The 5-year laryngectomy-free survival was 57% (95% CI, 48-66%) after surgery vs. 69% (95% CI, 64-75%) after chemoradiotherapy (p < 0.01). In stage III-IVB, these rates were 26% (95% CI, 16-39%) vs. 47% (95% CI, 36-59%), respectively (p < 0.01). Aspiration occurred in 7%, tracheostomy was necessary in 19.8% and feeding tube placement in 25.4%. Feeding tube and tracheostomy necessity was higher in the initially surgically treated group. Primary surgery (HR: 1.67, 95% CI: 1.19-2.32; p < 0.01), stage III-IVB (HR: 4.07, 95% CI: 2.97-5.60; p < 0.01) and tumor recurrence (HR: 3.83, 95% CI: 2.79-5.28; p < 0.01) remained as adverse factors for laryngectomy-free survival. CONCLUSIONS Preserving the laryngeal function after cancer treatment is challenging. Advanced tumor stages, primary surgery and recurrence are related to a poor functional outcome. Therefore, the criteria for initial decision-making needs to be further refined

Robotic middle ear access for cochlear implantation: first in man

To demonstrate the feasibility of robotic middle ear access in a clinical setting, nine adult patients with severe-to-profound hearing loss indicated for cochlear implantation were included in this clinical trial. A keyhole access tunnel to the tympanic cavity and targeting the round window was planned based on preoperatively acquired computed tomography image data and robotically drilled to the level of the facial recess. Intraoperative imaging was performed to confirm sufficient distance of the drilling trajectory to relevant anatomy. Robotic drilling continued toward the round window. The cochlear access was manually created by the surgeon. Electrode arrays were inserted through the keyhole tunnel under microscopic supervision via a tympanomeatal flap. All patients were successfully implanted with a cochlear implant. In 9 of 9 patients the robotic drilling was planned and performed to the level of the facial recess. In 3 patients, the procedure was reverted to a conventional approach for safety reasons. No change in facial nerve function compared to baseline measurements was observed. Robotic keyhole access for cochlear implantation is feasible. Further improvements to workflow complexity, duration of surgery, and usability including safety assessments are required to enable wider adoption of the procedure

Minimally Invasive Lateral Endoscopic Multiport Approach to the Infratemporal Fossa: A Cadaveric Study.

OBJECTIVE Expanded endoscopic endonasal approaches to the infratemporal fossa (ITF) are increasingly performed due to the improved visualization and the less morbidity in comparison to the classic open approaches. However, only a few studies in the literature investigated the lateral endoscopic access to the ITF. The purpose of our study is to examine the ITF with the minimal invasive endoscopically assisted Gillies approach with the trial of its expansion through a double port technique. MATERIALS AND METHODS The ITF was examined in 10 sides of five cadaver heads using a lateral endoscopic assisted approach. Moreover, a double portal technique was developed to allow bimanual dissection. Specific long angled skull base instruments were used for the dissection under stereotactic guidance. RESULTS The endoscopic assisted Gillies approach permitted a minimally invasive access to the complete anteroposterior extension of the ITF with sufficient mobility of the surgical instruments. A new anatomical classification for the ITF from a lateral endoscopic perspective was introduced. The addition of the second port gave the opportunity for bimanual dissection. CONCLUSIONS This cadaveric study shows the feasibility of an endoscopically assisted lateral approach to the ITF. Furthermore, the addition of a posterior port expands the approach through increasing the working area and enable a bimanual dissection technique. Either performed alone or in combination with an anterior endoscopic transnasal approach, the hereby proposed technique can offer a minimally invasive access to the ITF. The development of specifically designed instruments would further improve the impact and ease of this promising approach

Pleomorphic Adenoma of External Auditory Canal: Case Report of First Endoscopic Resection and Literature Review

Ceruminous pleomorphic adenoma is a very rare, mostly benign tumor originating from the ceruminal glands in the external auditory canal. Histologically, it is a mixed tumor with epithelial and stromal parts of different proportions, and is recognized today by the World Health Organization (WHO) as a ceruminous adenoma. Similar to the pleomorphic adenoma of salivary glands, recurrence or malignant degeneration with cellular atypia and metastasis can occur on rare occasions. Here, we describe an 87-year old female patient with a growing spherical mass in the right external auditory canal. After exclusive endoscopic tumor resection, a ceruminous pleomorphic adenoma was histologically diagnosed. Due to the absence of nuclear pleomorphism, no increased mitotic rate, no perineural invasion and no fusion transcripts of the MYB or MYBL1 gene loci, an adenoid cystic carcinoma could be excluded. The postoperative course was without any evidence of complications. A literature review identified 44 articles with 49 patients that were considered. Hearing loss and ear sensations were the most commonly reported symptoms. Most cases underwent an excision via an endaural or retroauricular approach. Recurrences were described in four patients, three of which had a malignant transformation. Keywords: Pleomorphic adenoma; ceruminal gland tumor; ceruminous adenoma; endoscopic ear surgery; external auditory canal

Synchrotron radiation imaging revealing the sub-micron structure of the auditory ossicles.

PURPOSE Synchrotron-based X-ray Phase Contrast Imaging (SR X-PCI) allows, thanks to a highly coherent and powerful X-ray beam, the imaging of surface and cross-sectional tissue properties with high absorption-contrast. The objective of this study is to investigate the sub-micron structure of the ossicular chain. The understanding of its morphological properties at sub-micron scale will help to refine the understanding of its structural properties. The investigation of intact, non-decalcified and unstained ossicular bones allows to study the spatial relationship between surface properties, internal structure and tomographical slides. MAIN RESULTS The tomography datasets with a pixel size of 0.65 μm were reconstructed and 3D volume rendering models of all specimens were analyzed. Based on surface models, the surfaces of the articulations, the insertion of the tensor tympani and stapedial muscle tendons and the nutritional foramina, where the vessels penetrate the ossicles, were visualized. Moreover, a branched network of inner channels could be represented and its connection to the nutritional foramen was demonstrated. Looking at the tomographic structure of the three ossicles a mineralization pattern for every auditory bone was described, indicating a considerable variation throughout the bones. CONCLUSIONS This study investigates the submicron-structure of the auditory ossicles at a pixel size of 0.65 μm, which is to the best of our knowledge the highest resolution reported in the investigation of the human auditory system so far. The provided data helps in the further understanding of the anatomical conformation of the ossicular chain