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Background: Temporal bone resection (TBR) with or without neck dissection (ND) is performed for otologic malignancies with occult or clinical cervical lymph node metastases. To date, characterization of post-operative complications in single institution case series may be non-representative of real-world outcomes. Here, we used data from the National Inpatient Sample (NIS) to comprehensively assess the complications encountered, their frequencies, and to identify underlying risk factors to improve future outcomes. Methods: The population was patients undergoing TBR and ND derived from the NIS between the years of 2017 and 2019. We utilized ICD-10 diagnosis codes to identify patients with post-operative complications, those discharged to non-home facilities (DNHF), and those with increased length of stay (LOS). Multivariable regression was performed to identify significant variables related to the above outcomes. Results: Ninety of 277 patients that underwent LTBR with ND had postoperative complications. Wound complications were the most frequent complication, occurring in 11 (4%) of patients, followed by CSF leak (n = 6; 2.2%), with acute respiratory failure being the most common medical complication (n = 4; 1.4%). Sixteen percent (45/277) were discharged to a facility besides home. Dementia (OR = 7.96; CI95 3.62-17.48), anemia (OR = 2.39; CI95 1.15-4.99), congestive heart failure (OR = 5.31; CI95 1.82-15.45), COPD (OR = 3.70; CI95 1.35-10.16), and history of prior stroke (OR = 8.50; CI95 1.55-46.68) increased the odds of DNHF. When evaluating LOS (median = 5 days, IQR = 1, 9), anemia (OR = 5.49; CI95 2.86-10.52), and Medicaid insurance (OR = 3.07; CI95 1.06-10.52) were found to increase the LOS. Conclusions: The vast majority of patients undergoing LTBR with ND have no complications and are discharged within a week. Liver disease is a risk factor for medical complications and increased charges. Patients with dementia or a prior stroke are at risk for DNHF, and those with prior anemia are at risk for a wound complication. Lay Summary: This study identified factors related to worse post-operative outcomes in patients undergoing temporal bone resection and neck dissection. Although safe for most patients, an existing diagnosis of liver disease, stroke, dementia, and anemia specifically are at risk for developing negative outcomes. Level of Evidence: 3. [ABSTRACT FROM AUTHOR]

Rosai-Dorfman Disease (RDD) is a rare, benign, idiopathic histiocytic proliferative disorder, with its occurrence in the cranial bones being particularly uncommon and prone to misdiagnosis in preoperative radiological examinations. This article reports a case of RDD in the left temporal bone. The radiological presentation of intraosseous RDD includes osteolytic bone destruction, infrequent periosteal reaction, clearly defined tumor margins, and marked uniform enhancement on contrast-enhanced scans. However, these radiological features lack specificity, highlighting the necessity of histopathological examination for a definitive diagnosis, especially for the rarer extranodal subtypes of RDD. Surgical excision of the lesion can lead to favorable therapeutic outcomes. [ABSTRACT FROM AUTHOR]

Objective: Temporal bone dissection is a difficult skill to acquire, and the challenge has recently been further compounded by a reduction in conventional surgical training opportunities during the coronavirus disease 2019 pandemic. Consequently, there has been renewed interest in ear simulation as an adjunct to surgical training for trainees. We review the state-of-the-art virtual temporal bone simulators for surgical training. Materials and methods: A narrative review of the current literature was performed following a Medline search using a pre-determined search strategy. Results and analysis: Sixty-one studies were included. There are five validated temporal bone simulators: Voxel-Man, CardinalSim, Ohio State University Simulator, Melbourne University's Virtual Reality Surgical Simulation and Visible Ear Simulator. The merits of each have been reviewed, alongside their role in surgical training. Conclusion: Temporal bone simulators have been demonstrated to be useful adjuncts to conventional surgical training methods and are likely to play an increasing role in the future. [ABSTRACT FROM AUTHOR]

Purpose: The opportunities for surgical training and practice in the operating room are in decline due to limited resources, increased efficiency demands, growing complexity of the cases, and concerns for patient safety. Virtual reality (VR) offers a novel opportunity to enhance surgical training and provide complementary three-dimensional experience that has been usually available in the operating room. Since VR allows viewing and manipulation of realistic 3D models, the VR environment could enhance anatomical and topographical knowledge, in particular. In this study, we explored whether incorporating VR anatomy training improves novices' performance during mastoidectomy over traditional methods. Methods: Thirty medical students were randomized into two groups and taught mastoidectomy in a structured manner. One group utilized a VR temporal bone model during the training while the other group used more traditional materials such as anatomy books. After the training, all participants completed a mastoidectomy on a 3D-printed temporal bone model under expert supervision. Performance during the mastoidectomy was evaluated with multiple metrics and feedback regarding the two training methods was gathered from the participants. Results: The VR training method was rated better by the participants, and they also needed less guidance during the mastoidectomy. There were no significant differences in operational time, the occurrence of injuries, self-assessment scores, and the surgical outcome between the two groups. Conclusion: Our results support the utilization of VR training in complete novices as it has higher trainee satisfaction and leads to at least as good results as the more traditional methods. [ABSTRACT FROM AUTHOR]

Background: Eagle's syndrome or stylalgia is a relatively rare condition that usually presents with throat pain and dysphagia. Most cases are asymptomatic, and diagnosis is difficult owing to the vague nature of the symptoms. There is a female preponderance. In most cases, the bony tip of the styloid process (SP) is palpable upon careful palpation of the ipsilateral tonsillar fossa. X-ray (Towne's view) or an orthopantomogram indicates the length of the styloid process or the ossified stylohyoid complex (OSHC). Computerized tomography (CT) of the skull base, apart from measuring length, provides additional details such as medial or ventral angulation and relation to the surrounding neurovascular structures. Case presentation: A 40-year-old female patient who presented to our hospital with left-sided throat pain and pricking sensation. After workup, she was diagnosed with left-sided stylalgia. X-ray (Towne's view) showed that the left styloid process was 27 mm long, and the right styloid process was 24 mm long. CT of the skull base measured the length and angulation of the styloid process on both sides (sagittal and transverse angles), which were found to be 60° and 61° on the left and 64° and 60° on the right side, respectively. The patient underwent left styloidectomy under general anesthesia. Postoperatively, the symptoms were completely relieved by day 7. Conclusion: Stylalgia is usually diagnosed on the basis of the elongated styloid process. Solely using the length of the styloid process as a parameter for diagnosis leads to misdiagnosis of cases that present with normal length of the styloid process. This article highlights the importance of CT scans in measuring the angulation of the ossified stylohyoid complex in such cases for accurate diagnosis. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic led to a temporary lapse in the development of otolaryngology trainee operative skills due to the cancellation of elective procedures and redeployment of trainees and attendings to COVID-19 units. Although transient, this disruption provided an opportunity for otolaryngology programs to develop contingency plans and formalize nascent simulation training curricula. Integration of formal simulation training alongside current didactic and surgical education may offset lost exposure during surgically lean times while providing the framework and resources for enhanced baseline training. Here, we provide an up-to-date overview of surgical simulation models in otolaryngology and identify easily implementable, low-cost, low fidelity models for junior trainees. By taking advantage of rapid advancements in technology and a paradigm shift to a more hands-on approach in medical education, formal simulation training may prove to be a beneficial tool at all stages of residency training, allowing for expanded peer-mentored skill development and providing a safe haven during unforeseen disruptions in surgical case volume. [ABSTRACT FROM AUTHOR]

Preoperative simulation using a three‐dimensional printer is effective to perform safe surgery by knowing the range limit of drilling in the temporal bone. Moreover, simulations using models are thought to be useful for education of young surgeon. [ABSTRACT FROM AUTHOR]

Stapes gusher is a massive flow of perilymph and cerebrospinal fluid leak that fills the middle ear immediately after surgical opening of the labyrinth, such as during stapedectomy. Stapes gusher usually occurs as the result of a congenital malformation that causes an abnormal communication between the perilymphatic space and the subarachnoid space involving the internal auditory canal or the cochlear duct. To date, the potential risk of stapes gusher cannot be assessed preoperatively, as there are not pathognomonic signs suggestive of this complication. However, high-resolution computed tomography scan (HRCT) of the temporal bone can provide information that may help recognizing patients at risk. Recently, an anatomic evaluation of the inner ear with oblique reformation at HRCT has been described. This reformation offers a new and more detailed topographic vision of temporal bone structures compared to the classic axial and coronal planes and may help identifying anatomical alterations otherwise not visible. In this article, we present a case of stapes gusher and the role of preoperative HRCT with oblique reformation in its prevention. [ABSTRACT FROM AUTHOR]

Purpose: Temporal bone surgery requires excellent surgical skills and simulation-based training can aid novices' skills acquisition. However, simulation-based training is challenged by early stagnation of performance after few performances. Structured self-assessment during practice might enhance learning by inducing reflection and engagement in the learning task. In this study, structured self-assessment was introduced during virtual reality (VR) simulation of mastoidectomy to investigate the effects on subsequent performance during cadaveric dissection. Methods: A prospective educational study with comparison with historical controls (reference cohort). At a temporal bone dissection course, eighteen participants performed structured self-assessment during 3 h of VR simulation mastoidectomy training before proceeding to cadaver dissection (intervention cohort). At a previous course, eighteen participants received identical VR simulation training but without the structured self-assessment (reference cohort). Final products from VR simulation and cadaveric dissection were recorded and assessed by two blinded raters using a 19-point modified Welling Scale. Results: The intervention cohort completed fewer procedures (average 4.2) during VR simulation training than the reference cohort (average 5.7). Nevertheless, the intervention cohort achieved a significantly higher average performance score both in VR simulation (11.1 points, 95% CI [10.6–11.5]) and subsequent cadaveric dissection (11.8 points, 95% CI [10.7–12.8]) compared with the reference cohort, who scored 9.1 points (95% CI [8.7–9.5]) during VR simulation and 5.8 points (95% CI [4.8–6.8]) during cadaveric dissection. Conclusions: Structured self-assessment is a valuable learning support during self-directed VR simulation training of mastoidectomy and the positive effect on performance transfers to subsequent cadaveric dissection performance. [ABSTRACT FROM AUTHOR]

Abstract Preoperative simulation using a three‐dimensional printer is effective to perform safe surgery by knowing the range limit of drilling in the temporal bone. Moreover, simulations using models are thought to be useful for education of young surgeon.

Objective: The Portsmouth Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity ('P-POSSUM') is a two-part scoring system that includes a physiological assessment and a measure of operative severity. This study sought to determine whether risk estimates for this scoring system could be used in major head and neck reconstructive surgery. Method: A retrospective review was performed of patients undergoing resection for a temporal bone malignancy in a single head and neck centre in Dublin, Ireland, from 2002 to 2021. Results: The mean ± standard deviation morbidity estimate calculated using the scoring system was 47.6 per cent ± 19.5 per cent. The actual rate of complications was 47 per cent. The optimal cut-off for the scoring system was calculated using the Youden index from the receiver operating characteristic curve, which was 40.5 per cent in this case. Conclusion: The study indicates that the Portsmouth Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity is a useful tool for predicting morbidity risk in patients undergoing head and neck resection with reconstruction for temporal bone malignancies. [ABSTRACT FROM AUTHOR]

Objective: Temporal bone simulation is now commonly used to augment cadaveric education. Assessment of these tools is ongoing, with haptic modeling illustrating dissimilar motion patterns compared to cadaveric opportunities. This has the potential to result in maladaptive skill development. It is hypothesized that trainee drill motion patterns during printed model dissection may likewise demonstrate dissimilar hand motion patterns. Methods: Resident surgeons dissected 3D-printed temporal bones generated from microCT data and cadaveric simulations. A magnetic position tracking system (TrakSTAR Ascension, Yarraville, Australia) captured drill position and orientation. Skill assessment included cortical mastoidectomy, thinning procedures (sigmoid sinus, dural plate, posterior canal wall) and facial recess development. Dissection was performed by 8 trainees (n = 5 < PGY3 > n = 3) using k-cos metrics to analyze drill strokes within position recordings. K-cos metrics define strokes by change in direction, providing metrics for stroke duration, curvature, and length. Results: T -tests between models showed no significant difference in drill stroke frequency (cadaveric = 1.36/s, printed = 1.50/s, P <.40) but demonstrate significantly shorter duration (cadaveric = 0.37 s, printed = 0.16 s, P <.01) and a higher percentage of curved strokes (cadaveric = 31, printed = 67, P <.01) employed in printed bone dissection. Junior staff used a higher number of short strokes (junior = 0.54, senior = 0.38, P <.01) and higher percentage of curved strokes (junior = 35%, senior = 21%, P <.01). Conclusions: Significant differences in hand motions were present between simulations, however the significance is unclear. This may indicate that printed bone is not best positioned to be the principal training schema. [ABSTRACT FROM AUTHOR]

Otic capsule dehiscences create a pathological third window in the inner ear that results in a dissipation of the acoustic energy consequent to the lowered impedance. Superior semicircular canal dehiscence (SSCD) was identified by Minor et al in 1998 as a syndrome leading to vertigo and inner ear conductive hearing loss. The authors also reported the relation between the dehiscence and pressure- or sound-induced vertigo (Tullio's phenomenon). Prevalence rates of SSCD in anatomical studies range from 0.4% to 0.7% with a majority of patients being asymptomatic. The observed association with other temporal bone dehiscences, as well as the propensity toward a bilateral or contralateral "near dehiscence," raises the question of whether a specific local bone demineralization or systemic mechanisms could be considered. The present report regard a case of a patient with a previous episode of meningitis, with a concomitant bilateral SSCD and tegmen tympani dehiscence from the side of meningitis. The patient was affected by dizziness, left moderate conductive hearing loss, and pressure/sound-induced vertigo. Because of disabling vestibular symptoms, the patient underwent surgical treatment. A middle cranial fossa approach allowed to reach both dehiscences on the symptomatic side, where bone wax and fascia were used for repair. At 6 months from the procedure, hearing was preserved, and the vestibular symptoms disappeared. [ABSTRACT FROM AUTHOR]

Giant cell tumors (GCTs) and giant cell granulomas (GCGs) are giant cell-rich lesions that occur extremely rarely in the temporal bone and have similar clinical presentations. We aimed to analyze the clinical features and introduce our staging system and surgical treatment. Forty-six patients pathologically diagnosed with a giant cell lesion involving the temporal bone between October 2001 and October 2020 were reviewed retrospectively. The clinical characteristics, surgical approaches, and risk factors for recurrence were analyzed. GCTs and GCGs presented as masses centered on the temporomandibular joint with similar imaging features, including a thin, calcified shell and central scattered calcifications on a computed tomography scan. Differences were detected on magnetic resonance imaging in 29.6% (4/14) of GCG and 50% (16/32) of GCT cases; the remaining cases were not distinguishable. Based on our staging system and surgical strategy, 31.8% (7/22) of GCT and 10% (1/10) of GCG cases experienced recurrence, which compares to recurrence rates of 60% in GCT cases and 20% in GCG cases in previous studies. Specific clinical and preoperative imaging features help to make a diagnosis of temporal giant cell-rich lesions. Our staging system and surgical strategy could help surgeons tailor the surgical strategy. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the impact of 3D-printed temporal bone models with two different material transparencies on trainees' mastoidectomy performance., Methods: Eleven ORL residents performed two anatomical mastoidectomies with posterior tympanotomy on two 3D-printed models with different transparency and VR simulation training. Participants where divided into two groups based on their experience. Within each group participants were randomized to start with the model printed in a completely opaque material or in a material featuring some degree of transparency. After drilling on 3D-printed models, the participants performed two similar mastoidectomies on human cadavers: one on the left side of one cadaver and one on the right side of another cadaver. After drilling 3D-printed models and cadavers, the final-product performances were evaluated by two experienced raters using the 26-item modified Welling Scale. Participants also evaluated the models using a questionnaire., Results: Overall, the participants performed 25 % better on the 3D-printed models featuring transparency compared to the opaque models (18.6 points vs 14.9 points, mean difference = 3.7, 95 % CI 2.0-5.3, P < 0.001)). This difference in performance was independent of which material the participants had drilled first. In addition, the residents also subjectively rated the transparent model to be closer to cadaver dissection. The experienced group starting with the 3D-printed models scored 21.5 points (95 % CI 20.0-23.1), while the group starting with VR simulation training score 18.4 points (95 % CI 16.6-20.3)., Conclusion: We propose that material used for 3D-printing temporal bone models should feature some degree of transparency, like natural bone, for trainees to learn and exploit key visual cues during drilling., Competing Interests: Declaration of competing interest None., (Copyright © 2024. Published by Elsevier B.V.)

Hypothesis: Evaluation of the Slim Modiolar (SM) electrode in temporal bones (TB) will elucidate the electrode's insertion outcomes., Background: The SM electrode was designed for atraumatic insertion into the scala tympani, for ideal perimodiolar positioning and with a smaller caliber to minimize interference with cochlear biological processes., Methods: The SM electrode was inserted into TBs via a cochleostomy. First, the axial force of insertion was measured. Next, TBs were inserted under fluoroscopy to study insertion dynamics, followed by histologic evaluation of electrode placement and cochlear trauma. A subset of TBs were inserted with the Contour Advance (CA) electrode for comparison., Results: Sixteen of 22 insertions performed to measure the axial force of insertion had flat or near zero insertion force profiles. Six insertions had increased insertion forces, which were attributed to improper sheath depth before electrode insertion. Under real-time fluoroscopy, 23 of 25 TBs had uneventful insertion and good perimodiolar placement. There was 1 scala vestibuli insertion due to suboptimal cochleostomy position and 1 tip roll over related to premature electrode deployment. When compared with the CA electrode, 14 of 15 insertions with the SM electrode resulted in a more perimodiolar electrode position. No evidence of trauma was found in histologic evaluation of the 24 TBs with scala tympani insertions., Conclusion: TB evaluation revealed that the SM electrode exerts minimal insertion forces on cochlear structures, produces no histologic evidence of trauma, and reliably assumes the perimodiolar position. Nonstandard cochleostomy location, improper sheath insertion depth, or premature deployment of the electrode may lead to suboptimal outcomes., (Copyright © 2024, Otology & Neurotology, Inc.)

Abstract: A high-riding jugular bulb can complicate standard otologic and neurotologic approaches and must be taken into account during surgical planning., Competing Interests: M.-E.N. discloses that he is a shareholder of the following companies: 3M, Amgen, Pfizer, Johnson & Johnson, Kimberly Clark, Medtronic, and Nestle. P.W.G. discloses that he is a shareholder of the following companies: Amgen, Eli Lily, Medtronic, Merck, Novartis, Pfizer, and Roche. The remaining authors disclose no conflicts of interest., (Copyright © 2024, Otology & Neurotology, Inc.)

The petrosquamosal sinus is a rare and almost unknown emissary vein of the temporal bone. It traverses the middle cranial fossa along the petrosquamosal fissure and connects dural sinuses with extracranial venous networks. It is known to undergo normal involution during fetal and early postnatal life, and therefore is rarely found in humans. When encountered during surgery, it can be a significant source of bleeding hindering proper visualization of important surgical landmarks. Here we report the case of a PSS, encountered in a child during cochlear implantation surgery. We discuss its clinical significance and impact on the surgical approach. Laryngoscope, 134:4111-4113, 2024., (© 2024 The American Laryngological, Rhinological and Otological Society, Inc.)

Objective: To suggest a comprehensive algorithm for the surgical approach for correcting of sources of temporal bone CSF leaks., Methods: A case series for patients operated in a single academic tertiary referral center between 2011 and 4.2022. Included in the study were 46 patients, 5 of whom had a bilateral problem, resulting in 51 pathologic temporal bones. The presentation was an active CSF leak (38 patients) or bacterial otogenic meningitis (8 patients). Follow up ranged from 8 months to 5 years., Results: Of the 42 ears operated via the default middle fossa approach, 37 were successful (88 %) in controlling CSF leak. None had intracranial complications or sensorineural hearing loss. Location, number and size of the defects, hearing status, associated superior semicircular canal dehiscence, additional intra-temporal or intra-cranial pathologies may indicate a transmastoid approach. Of the six ears that had a canal wall up mastoidectomy as a primary procedure, one required revision due to ongoing CSF leak. Five revision cases and three primary cases were effectively sealed with a subtotal petrosectomy and obliteration. One was lost to follow-up. Hearing was reconstructed with bone-anchored hearing implants in 6 out of these 8 ears., Conclusions: The middle fossa approach could be used as a default approach for sealing TD. There are a number of indications for transmastoid approaches in both primary and revision cases. Obliteration of the ear was used in all revision cases. The suggested algorithm can help in planning surgery for temporal bone CSF leaks or a history of otogenic meningitis., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Anterior petrosectomy (AP) is a commonly recognized approach for accessing tumors located in the petrous apex region. The essence of AP lies in drilling the petrous part of the temporal bone within the Kawase quadrangle. In our study, we conducted radiological and anatomical analyses of the structures within the petrous portion of the temporal bone, evaluating their impact on the surgical field during AP., Methods: We conducted an analysis of 15 anatomical specimens and 20 3D reconstructions based on computed tomography scans of the middle ear. The analyzed structures included the impression of the trigeminal nerve, the groove of the greater petrosal nerve, the arcuate eminence, and the angle between eminentia arcuata and grove for greater petrosal nerve., Results: The mean surface area measured by radiological methods does not deviate significantly from the mean surface area measured by anatomical methods 276.265mm2 (interquartile range: 217.603-309.188) versus 233.21mm2 (interquartile range: 210.923-255.453) P = 0.051. We established a threshold 195,99mm2 for radiological determination of the surface area at which another approach should be considered. Additionally, we have developed corrections for specific radiological factors to enable a better assessment of anatomical conditions., Conclusions: Our results indicate that preoperative assessment of anatomical conditions based on 3D reconstructions of computed tomography of the middle ear can be a valuable tool in preoperative planning of surgery on tumors in the petroclival region using the AP. Further studies involving a larger sample size are necessary to validate the findings of our study., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Purpose: Otology and neuro-otology surgeries pose significant challenges due to the intricate and variable anatomy of the temporal bone (TB), requiring extensive training. In the last years 3D-printed temporal bone models for otological dissection are becoming increasingly popular. In this study, we presented a new 3D-printed temporal bone model named 'SAPIENS', tailored for educational and surgical simulation purposes., Methods: The 'SAPIENS' model was a collaborative effort involving a multidisciplinary team, including radiologists, software engineers, ENT specialists, and 3D-printing experts. The development process spanned from June 2022 to October 2023 at the Department of Sense Organs, Sapienza University of Rome. Acquisition of human temporal bone images; temporal bone rendering; 3D-printing; post-printing phase; 3D-printed temporal bone model dissection and validation., Results: The 'SAPIENS' 3D-printed temporal bone model demonstrated a high level of anatomical accuracy, resembling the human temporal bone in both middle and inner ear anatomy. The questionnaire-based assessment by five experienced ENT surgeons yielded an average total score of 49.4 ± 1.8 out of 61, indicating a model highly similar to the human TB for both anatomy and dissection. Specific areas of excellence included external contour, sigmoid sinus contour, cortical mastoidectomy simulation, and its utility as a surgical practice simulator., Conclusion: We have designed and developed a 3D model of the temporal bone that closely resembles the human temporal bone. This model enables the surgical dissection of the middle ear and mastoid with an excellent degree of similarity to the dissection performed on cadaveric temporal bones., (© 2024. The Author(s).)

Objective: The surgical treatment of Eagle syndrome involves an intra- or extraoral approach. This systematic review set out to consolidate current knowledge on the prevalence of complications associated with intraoral and external approaches., Methods: Seven main electronic and two gray literature databases were searched. Studies were blindly selected by two reviewers based on pre-defined eligibility criteria. Studies evaluating any type of complication in the treatment of Eagle syndrome were considered eligible. Risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal Checklist for studies reporting prevalence data, case reports, and case series. The Comprehensive Meta-Analysis software (Software version 3.0 - Biostat, Englewood, NJ, USA) was used to perform all meta-analyses., Results: Out of 1728 articles found on all databases, 36 were included for qualitative analysis. Twenty were included for quantitative analysis and meta-analysis., Conclusion: In this study, the highest rate of complications was found in the intraoral approach.

Objectives: To analyze anatomic variations of the temporal bone in congenital aural atresia (CAA) and their correlation with the Jahrsdoerfer score, in order to guide clinical selection of surgical treatment methods., Material and Methods: We retrospectively studied 53 patients (72 ears) with unilateral or bilateral CAA, including 34 ears with normal hearing as controls. Audiological and imaging data were collected and analyzed. We evaluated the Jahrsdoerfer score and anatomical variations, including tegmen mastoideum position, anterior sigmoid sinus displacement, and elevated jugular bulb., Results: The average air conduction hearing threshold (PTA4) ranged from 0.5 to 4 kHz was 65.48 ± 8.19 dBHL, with an average Jahrsdoerfer score of 4.93 ± 2.78. In CAA group, there was a higher prevalence and severity of anterior sigmoid sinus and low position of the tegmen mastoideum (P < 0.01). However, there was no significant difference in incidence rates among groups with high jugular bulb (P > 0.05). Anterior sigmoid sinus and high jugular bulb showed no correlation with the Jahrsdoerfer score, while the low position of the tegmen mastoideum had a weak correlation. The Jahrsdoerfer score did not adequately predict temporal bone anatomical abnormalities in CAA patients., Conclusion: CAA exhibit a higher incidence and greater severity of temporal bone anatomical abnormalities compared to the control group, and the Jahrsdoerfer score inadequately assesses these abnormalities. Anomalies like low position of the tegmen mastoideum, anterior sigmoid sinus, and high jugular bulb should also be considered as independent factors influencing surgical decisions for atresiaplasty., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Hypothesis: The retrolabyrinthine (presigmoid) approach has been utilized in various skull base surgeries but has not been fully utilized in the management of internal auditory canal (IAC) lesions, such as vestibular schwannoma (VS). Microsurgical retrolabyrinthine approach provides limited visualization of the IAC, while endoscopic-assisted techniques allow for further lateral exposure with labyrinthine preservation., Background: Traditional approaches to the IAC have the disadvantage of hearing sacrifice or retraction of brain tissue. With the introduction of endoscopic techniques and enhanced visualization, access to this region of complex anatomy is possible., Methods: Radiomorphometric and anatomical dissection was performed on two cadaveric temporal bones. High-resolution computed tomography was used to segment and delineate the volume of the IAC. Projected accessible IAC was compared to actual postdissection data with preservation of the posterior semicircular canal (PSCC) via the retrolabyrinthine corridor., Results: While preserving the PSCC, the 0° and 30° endoscopes visualized 57.1% and 78.6% of the IAC for cadaver 1, and 64.0% and 76.0% of the IAC for cadaver 2, respectively. Sacrificing the PSCC, the 0° and 30° endoscopes provided visualization of 78.6% 85.7% of the IAC for cadaver 1, and 88.0% and 95.1% of the IAC for cadaver 2, respectively., Conclusions: Retrolabyrinthine approach to resection of VS is a potentially viable hearing-preserving alternative to traditional approaches. This approach provides access to the majority of the IAC, while angled endoscopes or sacrifice of the PSCC can provide additional access toward the fundus. Further studies are needed to determine the clinical feasibility of this approach., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024, Otology & Neurotology, Inc.)

Purpose: Determine whether adult cochlear implant users with radiographic superior semicircular canal dehiscence experience clinically significant differences in audiological outcomes when compared to cochlear implant users with normal temporal bone anatomy., Materials and Methods: Retrospective, single institution review. Adult, post-lingual deaf patients implanted between 2010 and 2020. Inclusion criteria included age 18 years or older, available preoperative computed tomography imaging, and preoperative and postoperative AzBio audiological data for at least 6 months of cochlear implant use. Preoperative and postoperative AzBio Sentence Test scores were compared between patients with normal temporal bone anatomy and those with radiographic superior semicircular canal dehiscence or near dehiscence., Results: 110 patients met inclusion criteria. Mean AzBio score for normal temporal bone anatomy group improved from 35.2 % (SD 28.2) preoperatively to 70.3 % (SD 25.7) postoperatively, an improvement of 35.1 % (SD 28.6). Mean AzBio score for near dehiscent temporal bone anatomy group improved from 26.6 % (SD 28.9) preoperatively to 64.5 % (SD 30.6) postoperatively, an improvement of 37.9 % (SD 27.9). Mean AzBio score for dehiscent temporal bone anatomy group improved from 26.3 % (SD 20.4) preoperatively to 65.1 % (SD 27.6) postoperatively, an improvement of 38.7 % (SD 26.9). Utilizing the one-way analysis of variance test, there was no significant difference in audiologic outcomes between the three groups., Conclusions: Patients with complete or near complete radiographic superior canal dehiscence at the time of cochlear implantation achieve similar improvements in speech perception scores compared to normal anatomy adult cochlear implant users., Competing Interests: Declaration of competing interest No relationship to paper. Seilesh Babu, MD 1. Acclarent/Johnson & Johnson Honorarium. 2. Cochlear Corporation research grant. 3. Oticon Medical research grant., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective: Demonstrate the utility of 3D printed temporal bone models in individual patient preoperative planning and simulation., Methods: 3D models of the temporal bone were made from 5 pediatric and adult patients at a tertiary academic hospital with challenging surgical anatomy planned for cochlear implantation or exteriorization of cholesteatoma with complex labyrinthine fistula. The 3D models were created from CT scan used for preoperative planning, simulation and intraoperative reference. The utility of models was assessed for ease of segmentation and production and impact on surgery in regard to reducing intraoperative time and costs, improving safety and efficacy., Results: Three patients received cochlear implants, two exteriorization of advanced cholesteatoma with fistulas (1 internal auditory canal/cochlea, 1 all three semicircular canals). Surgical planning and intraoperative referencing to the simulations by the attending surgeon and trainees significantly altered original surgical plans. In a case of X-linked hereditary deafness, optimal angles and rotation maneuvers for cochlear implant insertion reduced operating time by 93 min compared to the previous contralateral side surgery. Two cochlear implant cases planned for subtotal petrosectomy approach due to aberrant anatomy were successfully approached through routine mastoidectomy. The cholesteatoma cases were successfully exteriorized without necessitating partial labyrinthectomy or labyrinthine injury. There were no complications., Conclusion: 3D printed models for simulation training, surgical planning and use intraoperatively in temporal bone surgery demonstrated significant benefits in designing approaches, development of patient-specific techniques, avoidance of potential or actual complications encountered in previous or current surgery, and reduced surgical time and costs., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: The fronto-temporo-orbito-zygomatic (FTOZ) craniotomy is a commonly utilized surgical approach for many complex skull base lesions, especially lesions traversing skull base compartments. This craniotomy has evolved over multiple stages, originating from the classic pterional craniotomy and many variations that have emerged over time., Methods: Few clinical and anatomic studies have both shaped these craniotomies as well as provided immense information about instances in which they are most useful. We review the origin and history of the one-piece and two-piece fronto-temporo-orbito-zygomatic craniotomy and deliberate their advantages and disadvantages., Results: The FTOZ craniotomy provides access to the orbit as well as to multiple compartments in the cranium (anterior, middle and upper third posterior cranial fossae); thus, offering a multi-corridor approach to complex skull base lesions. The one-piece and two-piece fronto-temporo-orbitozygomatic craniotomies are two particularly notable variations that have stood the test of time. Selection between the two variations is mostly surgeon preference and comfort with the technique; however, there are certain indications that specifically suit each approach. Additionally, a pictorial review has been crafted to clearly illustrate the cuts to be made in both methods., Conclusion: Understanding the evolution of this craniotomy and surgical approach provides an insight into accessing complex skull base pathologies with minimal brain retraction via safe and viable corridors., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Introduction: Round window approach and cochleostomy approach can have different depth of electrode insertion during cochlear implantation which itself can alter the audiological outcomes in cochlear implant., Objective: The current study was conducted to determine the difference in the depth of electrode insertion via cochleostomy and round widow approach when done serially in same temporal bone., Methodology: This is a cross-sectional study conducted in the Department of Otorhinolaryngology in conjunction with Department of Anatomy and Department of Diagnostic and Interventional Radiology over a period of 1 year. 12-electrode array insertion was performed via either approach (cochleostomy or round window) in the cadaveric temporal bone. HRCT temporal bone scan of the implanted temporal bone was done and depth of insertion and various cochlear parameters were calculated., Result: A total of 12 temporal bones were included for imaging analysis. The mean cochlear duct length was 32.892 mm; the alpha and beta angles were 58.175° and 8.350°, respectively. The mean angular depth of electrode insertion via round window was found to be 325.2° (SD = 150.5842) and via cochleostomy 327.350 (SD = 112.79) degree and the mean linear depth of electrode insertion via round window was found to be 18.80 (SD = 4.4962) mm via cochleostomy 19.650 (SD = 3.8087) mm, which was calculated using OTOPLAN 1.5.0 software. There was a statically significant difference in linear depth of insertion between round window and cochleostomy. Although the angular depth of insertion was higher in CS group, there was no statistically significant difference with round window type of insertion., Conclusion: The depth of electrode insertion is one of the parameters that influences the hearing outcome. Linear depth of electrode insertion was found to be more in case of cochleostomy compared to round window approach (p = 0.075) and difference in case of angular depth of electrode insertion existed but not significant (p = 0.529)., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

With the advent of operable 3-dimensional (3D)-printed models, case preparation could occur outside of the cadaveric laboratory. The objective of this study was to design a mobile drilling station that can be used for surgical practice in a variety of clean workplaces. Using materials obtained from hardware stores and online retailers, a wheelable drilling station was constructed to mimic laboratory conditions while also being easily maneuverable into clinic rooms. The station houses the otologic drill, suction, and irrigation mechanisms, is height adjustable, and has a shielded workspace. The mobile drilling station was moved into a microscope-containing otolaryngology clinic room where faculty and trainees were asked to drill a pediatric 3D-printed temporal bone followed by completing an evaluation survey. This is the first mobile drilling station described in the literature and can be easily constructed, mobilized, and used in an otolaryngology clinic for dedicated surgical practice using 3D-printed models., (© 2024 American Academy of Otolaryngology–Head and Neck Surgery Foundation.)

Purpose: To assess the audiometric outcomes following surgical repair of spontaneous temporal bone cerebrospinal fluid otorrhea and compare different surgical approaches., Materials and Methods: Retrospective review of adults (≥18 years old) who underwent repair of spontaneous CSF leak between 2011 and 2022. Audiometric outcomes were compared across the three surgical groups: transmastoid, middle cranial fossa and combined., Results: Thirty-nine patients (40 ears) met the inclusion criteria (71.8 % females; mean age 59.77 +/- 12.4). Forty-two percent underwent transmastoid, 12.5 % middle cranial fossa and 45 % transmastoid-middle cranial fossa. Four patients (10 %) had recurrence, 3 in the transmastoid group and 1 in the combined approach. The mean change in air-bone gap (ABG) for all patients (postoperative-preoperative) was -7.4 (paired t-test, p-value = 0.0003). The postoperative ABG was closed in 28 (70 %) ears (postoperative ABG ≤ 15). The mean change in pure tone average (PTA) for all patients (postoperative-preoperative) was -4.1 (paired t-test, p-value = 0.13). The mean change in word recognition scores (WRS) for all patients (postoperative-preoperative) was -3 (paired t-test, p-value = 0.35). On multivariable analysis (controlling for site and reconstruction material), there was no significant difference in ABG, PTA and WRS change between surgical groups., Conclusions: Transmastoid, middle cranial fossa and combined approaches are all effective in treatment of spontaneous CSF leaks and all showed mean decrease in post-operative ABG. Transmastoid approach showed the greatest decrease in ABG and PTA (although middle cranial fossa approach shows the greatest decrease, when excluding profound hearing loss in a patient with superior canal dehiscence). Further studies comparing audiometric outcomes are needed., Competing Interests: Declaration of competing interest No conflicts of interest or funding were declared by any of the authors., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Lateral temporal bone resections are used in the management of locally advanced peri-auricular cutaneous squamous cell carcinomas, but there is still conflicting evidence regarding the staging, surgical and adjuvant treatment decisions. Methods: A retrospective analysis was performed on all patients who underwent lateral temporal bone resection for cutaneous squamous cell carcinoma between January 2015 and December 2019 at a dedicated tertiary oncology referral centre. Results: Twenty-nine patients were included, with a median age of 77 years. Computed tomography, magnetic resonance imaging and positron emission tomography showed good diagnostic accuracy in identifying disease in the parotid gland, external auditory canal and mastoid bone, but had poor sensitivity in identifying cervical nodal metastasis. Six patients had recurrence at a median of 4.8 months post-operatively. Tumour differentiation (p = 0.0040) and post-operative radiotherapy (p = 0.0199) were associated with significantly better recurrence-free survival. Conclusion: Lateral temporal bone resection for peri-auricular cutaneous squamous cell carcinoma requires careful surgical planning using clinico-radiological correlation, particularly in patients with poorly differentiated tumours. [ABSTRACT FROM AUTHOR]

It is still far away from most of us in that it requires complex 3D modeling. To investigate a more precision, simple, convenient and economical three-dimensional (3D) printed temporal bone model printed by a commercial desktop 3D printer, which can be widely promoted and applied in the training of beginners in otology. The CT data of the temporal bone were imported into Mimics to construct a 3D digital model of the temporal bone. After loaded into a high-precision 3D printer, a high-precision temporal bone model was printed at a scale of 1:1. Then, the model was evaluated by 5 senior attending physicians, including its morphological accuracy, simulation about surgery, advantages and educational value, using the 7-point Likert scale. A life-like temporal bone model was successfully printed out. Five senior attending physicians all thought that the printed model was similar to the natural temporal bone in physical properties and the haptic sensation of bone drilling, and was accurate, simple, convenient and effective. In addition, the model was considered to be of high application value in the teaching of temporal bone anatomy and surgery simulation, which had a material cost of only 3 dollars. The high-precision 3D printed temporal bone model is highly similar to the natural temporal bone, and can be conveniently and effectively used in the training of simulating temporal bone surgery for beginners in otology. Its production is simple and economical, so it can be popularized on a large scale. [ABSTRACT FROM AUTHOR]

Purpose: To provide practical guidance to the operative surgeon by mapping the location, where acceptable straight-line virtual cochlear implant electrode trajectories intersect the facial recess. In addition, to investigate the influence of facial recess preparation, virtual electrode width and surgical approach to the cochlea on these available trajectories. Methods: The study was performed on imaging data from eight cadaveric temporal bones within the University of Melbourne Virtual Reality (VR) Temporal Bone Surgery Simulator. The facial recess was opened to varying degrees, and acceptable trajectory vectors with varying diameters were calculated for electrode insertions via cochleostomy or round window membrane (RWM). The percentage of acceptable insertion vectors through each location of the facial recess was visually represented using heatmaps. Results: Seven of the eight bones allowed for acceptable vector trajectories via both cochleostomy and RWM approaches. These acceptable trajectories were more likely to lie superiorly within the facial recess for insertion via the round window, and inferiorly for insertion via cochleostomy. Cochleostomy insertions required a greater degree of preparation and skeletonisation of the junction of the facial nerve and chorda tympani within the facial recess. The width of the virtual electrode had only marginal impact on the availability of acceptable trajectories. Heatmaps emphasised the intimate relationship the acceptable trajectories have with the facial nerve and chorda tympani. Conclusion: These findings highlight the differences in the acceptable straight-line trajectories for electrodes when implanted via the round window or cochleostomy. There were notable exceptions to both surgical approaches, likely explained by the variation of hook region anatomy. The methodology used in this study holds promise for translation to patient specific surgical planning. [ABSTRACT FROM AUTHOR]

Objective: Self-directed training represents a challenge in simulation-based training as low cognitive effort can occur when learners overrate their own level of performance. This study aims to explore the mechanisms underlying the positive effects of a structured self-assessment intervention during simulation-based training of mastoidectomy. Methods: A prospective, educational cohort study of a novice training program consisting of directed, self-regulated learning with distributed practice (5x3 procedures) in a virtual reality temporal bone simulator. The intervention consisted of structured self-assessment after each procedure using a rating form supported by small videos. Semi-structured telephone interviews upon completion of training were conducted with 13 out of 15 participants. Interviews were analysed using directed content analysis and triangulated with quantitative data on secondary task reaction time for cognitive load estimation and participants’ self-assessment scores. Results: Six major themes were identified in the interviews: goal-directed behaviour, use of learning supports for scaffolding of the training, cognitive engagement, motivation from self-assessment, self-assessment bias, and feedback on self-assessment (validation). Participants seemed to self-regulate their learning by forming individual sub-goals and strategies within the overall goal of the procedure. They scaffolded their learning through the available learning supports. Finally, structured self-assessment was reported to increase the participants’ cognitive engagement, which was further supported by a quantitative increase in cognitive load. Conclusions: Structured self-assessment in simulation-based surgical training of mastoidectomy seems to promote cognitive engagement and motivation in the learning task and to facilitate self-regulated learning.

Purpose of Review: This systematic review investigates the recent literature and aims to determine the approach, efficacy, and timing of facial nerve decompression with or without grafting in temporal bone fractures with facial palsy., Recent Findings: The surgical management of facial palsy is reserved for a small population of cases in which electrophysiologic tests indicate a poor likelihood of spontaneous recovery. The transmastoid (TM), middle cranial fossa (MCF), and translabyrinthine (TL) approaches to the facial nerve provide access to the entire intracranial and intratemporal segments of the facial nerve. In temporal bone (TB) related facial palsy, the peri-geniculate and labyrinthine portions of the facial nerve are most commonly affected by either direct trauma and/or subsequent edema. When hearing is still serviceable, the combined TM/MCF approach provides the best access to these regions. In the presence of severe sensorineural hearing loss (SNHL), the TL approach is the most appropriate for total facial nerve exploration (this can be done in conjunction with simultaneous cochlear implantation if the cochlear nerve has not been avulsed). Grade I to III House-Brackmann (HB) results can be anticipated in timely decompression of facial nerve injury caused by edema or intraneuronal hemorrhage. Grade III outcomes, with slight weakness and synkinesis, is the outcome to be expected from the use of interpositional grafts or primary neurorrhaphy. In addition to good eye care and the use of systemic steroids (if not contraindicated in the acute trauma setting), surgical decompression with or without grafting/neurorrhaphy may be offered to patients with appropriate electrophysiologic testing, physical examination findings, and radiologic localization of injury., Summary: Surgery of the facial nerve remains an option for select patients. Here, we discuss the indications and results of treatment as well as the best surgical approach to facial nerve determined based on patient's hearing status and radiologic data. Controversy remains about whether timing of surgery (e.g., immediate vs. delayed intervention) impacts outcomes. However, no one with facial palsy due to a temporal bone fracture should be left with a complete facial paralysis., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Objectives: To evaluate the outcomes for patients after lateral temporal bone resection surgery for cutaneous squamous cell carcinoma and basal cell carcinoma, and to ascertain predictors of survival and treatment failure. Methods: A retrospective review was conducted of the medical records for all patients who underwent lateral temporal bone resection for cutaneous squamous cell carcinoma or basal cell carcinoma between 2007 and 2019 in Western Australia. Results: Thirty-seven patients underwent lateral temporal bone resection surgery. Median follow-up duration was 22 months. Twenty-five patients had squamous cell carcinoma and 12 had basal cell carcinoma. The overall survival rate at two years for patients with squamous cell carcinoma was 68.5 per cent. Pre-operative facial nerve involvement (determined via clinical or radiological evidence) was identified as a predictor of mortality (hazard ratio = 3.411, p = 0.006), with all patients dying before two years post-operatively. Locoregional tumour control was achieved in 81 per cent of cases (n = 30). Conclusion: Lateral temporal bone resection offers acceptable local control rates and survival outcomes. Caution should be used in offering this surgery to patients with clinical or radiological evidence of facial nerve involvement because of the relatively poorer survival outcomes in this subgroup. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the surgical procedures used to treat external auditory canal cancer with respect to avoiding postoperative infection of the temporal bone defect.Methods: Enrolled in the study were 52 patients with external auditory canal cancer surgically treated between July 2015 and October 2020 (38 lateral temporal bone resections, 12 subtotal temporal bone resections and 2 partial resections, accompanied by various combined procedures). Retrospective chart review was conducted taking into consideration postoperative infection, and univariate analysis of prognostic factors was performed.Results: In cases managed with subtotal temporal bone resection, no postoperative infections occurred. Cases managed with subtotal temporal bone resection demonstrated increased use of free-flap reconstruction, and longer antibiotic infusion period. On the other hand, analysis of cases managed with lateral temporal bone resection revealed 10 out of 38 patients with postoperative infection (26.3%). However, we couldn't find out any factors that contributed significantly to the prevention of postoperative infection, including the surgical procedures used to manage the defected space, which included free-flap implantation, obliteration with fat tissue, muscular flap rotation, and leaving the space empty without obliteration or reconstruction.Conclusion: In cases managed with lateral temporal bone resection, leaving the resected space empty did not increase the risk of infection. On the other hand, in cases with subtotal temporal bone resection, filling the surgical defect with an autologous bulk, including the free-flap reconstruction and fat obliteration, seems to prevent the infection. Moreover, prolonged antibiotic infusion may suppress postoperative infection of the temporal bone defect. [ABSTRACT FROM AUTHOR]

The aim of this article was to feature the use of giant bilobed flaps in surgical reconstruction after total or subtotal petrosectomy in oncology cases. The Esser technique was renewed and adopted for coverage huge skin loss. The authors reported 4 cases illustrated pre- and postoperative photography and intraoperative planning and schema. Good coverage and healing with no need for use of free tissue transfer or skin expanders or skin grafts was obtained. In authors' opinion, the cosmetic effect was acceptable. Surgical times of operation were significantly shorter. [ABSTRACT FROM AUTHOR]

Background: Eagle syndrome is caused by an elongated styloid process affecting carotid arteries and cranial nerves. Pain, dysphagia, tinnitus, paresthesia (classic subtype), and neurovascular events (vascular subtype) may be triggered by head movements or arise spontaneously. However, Eagle syndrome remains underappreciated in the neurological community. We aimed to determine the most common neurological and non-neurological clinical presentations in patients with Eagle syndrome and to assess the clinical outcome post-surgical resection in comparison to non-surgical therapies., Methodology: We conducted a systematic review of patient-level data on adults with Eagle syndrome, following PRISMA guidelines. We extracted data on demographics, presenting symptoms, neurological deficits, radiological findings, and treatments, including outcomes and complications, from studies in multiple indexing databases published between 2000 and 2023. The study protocol is registered with PROSPERO., Results: In total, 285 studies met inclusion criteria, including 497 patients with Eagle syndrome (mean age 47.3 years; 49.8% female). Classical Eagle (370 patients, 74.5%) was more frequent than vascular Eagle syndrome (117 patients, 23.5%, p < 0.0001). Six patients (1.2%) presented with both variants and the subvariant for four patients (0.8%) was unknown. There was a male preponderance (70.1% male) in the vascular subtype. A history of tonsillectomy was more frequent in classic (48/153 cases) than in vascular (2/33 cases) Eagle syndrome (Odds Ratio 5.2, 95% CI [1.2-22.4]; p = 0.028). By contrast, cervical movements as trigger factors were more prevalent in vascular (12/33 cases) than in classic (7/153 cases) Eagle syndrome (Odds Ratio 7.95, 95% CI [2.9-21.7]; p = 0.0001). Headache and Horner syndrome were more frequent in vascular Eagle syndrome and dysphagia and neck pain more prominent in classic Eagle syndrome (all p < 0.01). Surgically treated patients achieved overall better outcomes than medically treated ones: Eighty-one (65.9%) of 123 medically treated patients experienced improvement or complete resolution, while the same applied to 313 (97.8%) of 320 surgical patients (Odds Ratio 1.49, 95% CI [1.1-2.0]; p = 0.016)., Conclusions: Eagle syndrome is underdiagnosed with potentially serious neurovascular complications, including ischemic stroke. Surgical treatment achieves better outcomes than conservative management. Although traditionally the domain of otorhinolaryngologist, neurologist should include this syndrome in differential diagnostic considerations because of the varied neurological presentations that are amenable to effective treatment., Competing Interests: The authors declare that they have no competing interests., (© 2024 Hassani et al.)

Rosai-Dorfman Disease (RDD) is a rare, benign, idiopathic histiocytic proliferative disorder, with its occurrence in the cranial bones being particularly uncommon and prone to misdiagnosis in preoperative radiological examinations. This article reports a case of RDD in the left temporal bone. The radiological presentation of intraosseous RDD includes osteolytic bone destruction, infrequent periosteal reaction, clearly defined tumor margins, and marked uniform enhancement on contrast-enhanced scans. However, these radiological features lack specificity, highlighting the necessity of histopathological examination for a definitive diagnosis, especially for the rarer extranodal subtypes of RDD. Surgical excision of the lesion can lead to favorable therapeutic outcomes., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Lv, Hu, Xu and Yu.)

Purpose: Patient-to-image registration is a preliminary step required in surgical navigation based on preoperative images. Human intervention and fiducial markers hamper this task as they are time-consuming and introduce potential errors. We aimed to develop a fully automatic 2D registration system for augmented reality in ear surgery., Methods: CT-scans and corresponding oto-endoscopic videos were collected from 41 patients (58 ears) undergoing ear examination (vestibular schwannoma before surgery, profound hearing loss requiring cochlear implant, suspicion of perilymphatic fistula, contralateral ears in cases of unilateral chronic otitis media). Two to four images were selected from each case. For the training phase, data from patients (75% of the dataset) and 11 cadaveric specimens were used. Tympanic membranes and malleus handles were contoured on both video images and CT-scans by expert surgeons. The algorithm used a U-Net network for detecting the contours of the tympanic membrane and the malleus on both preoperative CT-scans and endoscopic video frames. Then, contours were processed and registered through an iterative closest point algorithm. Validation was performed on 4 cases and testing on 6 cases. Registration error was measured by overlaying both images and measuring the average and Hausdorff distances., Results: The proposed registration method yielded a precision compatible with ear surgery with a 2D mean overlay error of 0.65 ± 0.60 mm for the incus and 0.48 ± 0.32 mm for the round window. The average Hausdorff distance for these 2 targets was 0.98 ± 0.60 mm and 0.78 ± 0.34 mm respectively. An outlier case with higher errors (2.3 mm and 1.5 mm average Hausdorff distance for incus and round window respectively) was observed in relation to a high discrepancy between the projection angle of the reconstructed CT-scan and the video image. The maximum duration for the overall process was 18 s., Conclusions: A fully automatic 2D registration method based on a convolutional neural network and applied to ear surgery was developed. The method did not rely on any external fiducial markers nor human intervention for landmark recognition. The method was fast and its precision was compatible with ear surgery., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)