Estimating Cognitive Workload Using Task-Related Pupillary Responses in Simulated Drilling in Cochlear Implantation.

OBJECTIVES: Training of temporal bone drilling requires more than mastering technical skills with the drill. Skills such as visual imagery, bimanual dexterity, and stress management need to be mastered along with precise knowledge of anatomy. In otorhinolaryngology, these psychomotor skills underlie performance in the drilling of the temporal bone for access to the inner ear in cochlear implant surgery. However, little is known about how psychomotor skills and workload management impact the practitioners' continuous and overall performance. METHODS: To understand how the practitioner's workload and performance unfolds over time, we examine task-evoked pupillary responses (TEPR) of 22 medical students who performed transmastoid-posterior tympanotomy (TMPT) and removal of the bony overhang of the round window niche in a 3D-printed model of the temporal bone. We investigate how students' TEPR metrics (Average Pupil Size [APS], Index of Pupil Activity [IPA], and Low/High Index of Pupillary Activity [LHIPA]) and time spent in drilling phases correspond to the performance in key drilling phases. RESULTS: All TEPR measures revealed significant differences between key drilling phases that corresponded to the anticipated workload. Enlarging the facial recess lasted significantly longer than other phases. IPA captured significant increase of workload in thinning of the posterior canal wall, while APS revealed increased workload during the drilling of the bony overhang. CONCLUSION: Our findings contribute to the contemporary competency-based medical residency programs where objective and continuous monitoring of participants' progress allows to track progress in expertise acquisition. Laryngoscope, 2024.

An evaluation of morphometry and dehiscence of facial canal: a systematic review and meta-analysis of observational studies.

INTRODUCTION: The facial canal (FC) is an extensive bony canal that houses the facial nerve and occupies a central position in the petrous part of temporal bone. It is of utmost significance to otologists due to its dehiscence and relationship to the inner or middle ear components. The main objectives of current investigation are to detect variations in the reported values ​​of FC anatomy that may occur due to different methodology and to elucidate the influence of age and ethnic factors on the morphological features of FC. METHODS: The methodology is adapted to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Pooled weighted estimation was performed to calculate the mean length, angle, and prevalence of dehiscence. RESULTS: The cross-sectional shape of FC varied from circular to ellipsoid index and is 1.45 [95% CI, 0.86-2.6]. The mean length of the FC is 34.42 mm [95% CI, 27.62-40.13 mm] and the mean width or diameter is 1.35 mm [95% CI, 1.013-1.63 mm]. The length of the FC in fetuses and children is 21.79 mm [95% CI, 18.44-25.15 mm], and 26.92 mm [95% CI, 23.3-28.3 mm], respectively. In meta-regression, age is observed as a predictor and accounts for 36% of the heterogeneity. The prevalence of FC dehiscence in healthy temporal bones is 29% [95% CI, 20-40%]. CONCLUSION: The different segments of the FC exhibit significant variability and an unusually high incidence of dehiscence, which could potentially have clinical implications for the etiopathogenesis of facial nerve dysfunction.

Temporal Bone Histopathology of Atypical Cogan Syndrome.

Cogan's syndrome is a rare disorder first clinically defined in 1945, characterized by nonsyphilitic interstitial keratitis and progressive audiovestibular symptoms. Later, patients with audiovestibular dysfunction and various types of inflammatory eye disease were classified as having atypical Cogan's syndrome. The etiology and pathogenesis of Cogan's syndrome remain largely unknown. Here, we report a case of atypical Cogan's syndrome with a histological assessment of the temporal bone during the acute disease period. Temporal bone histology was compared to age- and gender-matched normal control, and our findings revealed endolymphatic hydrops and degenerative changes in various parts of the inner ear. Laryngoscope, 2024.

Synthetic temporal bone CT generation from UTE-MRI using a cycleGAN-based deep learning model: advancing beyond CT-MR imaging fusion.

OBJECTIVES: The aim of this study is to develop a deep-learning model to create synthetic temporal bone computed tomography (CT) images from ultrashort echo-time magnetic resonance imaging (MRI) scans, thereby addressing the intrinsic limitations of MRI in localizing anatomic landmarks in temporal bone CT. MATERIALS AND METHODS: This retrospective study included patients who underwent temporal MRI and temporal bone CT within one month between April 2020 and March 2023. These patients were randomly divided into training and validation datasets. A CycleGAN model for generating synthetic temporal bone CT images was developed using temporal bone CT and pointwise encoding-time reduction with radial acquisition (PETRA). To assess the model's performance, the pixel count in mastoid air cells was measured. Two neuroradiologists evaluated the successful generation rates of 11 anatomical landmarks. RESULTS: A total of 102 patients were included in this study (training dataset, n = 54, mean age 58 ± 14, 34 females (63%); validation dataset, n = 48, mean age 61 ± 13, 29 females (60%)). In the pixel count of mastoid air cells, no difference was observed between synthetic and real images (679 ± 342 vs 738 ± 342, p = 0.13). For the six major anatomical sites, the positive generation rates were 97-100%, whereas those of the five major anatomical structures ranged from 24% to 83%. CONCLUSION: We developed a model to generate synthetic temporal bone CT images using PETRA MRI. This model can provide information regarding the major anatomic sites of the temporal bone using MRI. CLINICAL RELEVANCE STATEMENT: The proposed algorithm addresses the primary limitations of MRI in localizing anatomic sites within the temporal bone. KEY POINTS: CT is preferred for imaging the temporal bone, but has limitations in differentiating pathology there. The model achieved a high success rate in generating synthetic images of six anatomic sites. This can overcome the limitations of MRI in visualizing key anatomic sites in the temporal skull.

Temporal bone mucocele with extension to mastoid in a 60-year-old male: a case report and literature review.

Introduction: Mucoceles, characterized by cystic lesions with sterile mucus accumulation, mostly occur in the paranasal but rarely affect the temporal-mastoid bone. The pathogenesis involves obstruction of natural drainage or cyst enlargement. Here, the authors present a rare case of temporal-mastoid mucocele with temporal hypertrophy. Case presentation: A 60-year-old male presented with progressive painless right temporal region swelling associated with diminished hearing, headache, fever and ear symptoms. Audiometry indicated a profound hearing loss in the right ear. Computed tomography (CT) of the right temporal bone and MRI brain revealed a large, destructive lesion involving the right temporal mastoid suggesting temporal-mastoid mucocele. Surgical excision of the mucocele and mastoid exploration were performed. Postoperative recovery was uneventful, with significant improvement in symptoms. Clinical discussion: Temporal bone mucoceles are rare, with few cases reported in the literature. Their etiology remains unclear, although chronic otitis media may be associated in some cases. Clinical presentations may vary, ranging from asymptomatic to symptoms such as serous otitis media, retroauricular edema, or cholesteatoma. Expansion of the mucocele cavity can lead to bone erosion or remodeling, potentially causing hearing loss. Differentials should include cholesteatoma, histiocytosis, and cholesterol granuloma. Imaging such as temporal bone CT and MRI are crucial for diagnosing, with characteristic findings on T2W images helping in differentiation. Surgical treatment, such as mastoidectomy with marsupialization or complete lesion removal, is indicated to prevent complications and reduce the risk of recurrence. Conclusion: This study reports a unique case of concomitant temporal-mastoid mucocele with involvement of organs of hearing with temporal bone hypertrophy.

The Role of Computed Tomography in the Diagnosis of Congenital Sensorineural Hearing Loss.

Introduction One of the paths in the investigation of congenital sensorineural hearing loss (CSNHL) is to try to characterize its etiology through the inner ear evaluation using high resolution computer tomography (CT) scans. With minor malformation, it is not always possible for a simple visual inspection to recognize if the structure in the inner ear is normal or not. Objective To verify if measurements of the inner ear are predictive of sensorineural hearing loss (SNHL) and suggest cutoff points of size limits. Methods Retrospective cross-sectional study of inner ear CT scan measurements of 214 patients, 50 with congenital SNHL (CSNHL) and 164 acquired SNHL (ASNHL) (control group). Results In the CSNHL group, central bony island (CBI) were 0.48 mm smaller ( p < 0.001), cochlear nerve aperture was (CNA) 0.10 mm smaller ( p < 0.001), and cochlea height was (CH) 0.15 mm smaller ( p < 0.001). Vestibular aqueduct (VA) and cochlea width (CW) were similar between groups (0.70 vs 0.72, p = 0.19, and 7.20 vs 7.15 p = 0.23). The predictive cutoff points for CSNHL were CBI = 3.6 mm, CAN = 1.4 mm, CH = 3.4 mm, CW = 7.0 mm, and VA = 0.9 mm. Conclusion Congenital sensorineural hearing loss determined a decrease in CBI, opening of the cochlear nerve (OCN), and CW. Thus, these measures, at the cutoff points indicated, should make us aware of the diagnosis of congenital hearing loss.

A Clinicopathological Study of Aural Polyps: A Retrospective Analysis in a Tertiary Care Hospital.

Introduction Aural polyps are a misnomer. Any lesion can present as a mass in the external auditory canal. Aural polyps are proliferation of the granulation tissue due to long standing inflammatory process with associated otalgia and otorrhea. Objectives To document the clinicoradiological presentations, intraoperative findings, and histopathological diagnosis of aural polyp, correlating them. Methods In our study 81 patients underwent treatment for aural polyps in the department of Ear, Nose, and Throat (ENT) from April 1997 to April 2022. Results were tabulated, a simple descriptive analysis was done using the Statistical Package Social Sciences software, and the results obtained were represented as percentages and presented in tables. Results The majority (38) of the patients presenting with aural polyps were diagnosed with mucosal and squamous type of CSOM, and 22 with simple granulation polyps. There were also 5 patients with malignant otitis externa, 3 patients had glomus tumors, 2 patients with retained foreign bodies, and 3 patients with brain herniation. We also identified aberrant internal carotid artery, high jugular bulb, one patient had facial nerve neuroma, one patient had polyp from the tragus diagnosed with tuberculosis, one patient with keratosis obturans, and one with exostosis. Conclusion A thorough detailed examination and mastoid exploration with radiological and histopathological evaluation is mandatory for better defining the definitive treatment. Utmost care and meticulousness are advised for the surgeons while dealing with aural polyps to avoid any complications.

Changes in paranasal sinus volumes, temporal bone pneumatization, internal acoustic canal and olfactory cleft dimensions over the centuries: a comparison of skulls from different epochs in Anatolia.

OBJECTIVES: Investigating changes in temporal bone pneumatization (TBP) and paranasal sinus volumes (PSV) across different eras may help understanding not only changes in skull anatomy but also pathophysiology of chronic otitis media and sinusitis, respectively, which are common health problems. METHODS: Eight skulls from the second century AD, 20 skulls were from the 10th-11th centuries AD, 20 skulls from the 16th-19th centuries AD, and 60 contemporary skulls were included in this cross-sectional observational study. Using computerized tomography (CT) scans, the PSV were calculated by multiplying the height, width, and antero-posterior distance of the sinuses. TBP was divided into three types. Internal acoustic canal (IAC) length and width, and olfactory cleft (OC) width were measured. RESULTS: No statistically significant differences were found between the paranasal sinus (frontal, maxillary, and sphenoid) volumes between the groups. However, TBP decreased statistically significantly over time on both sides of the skulls (p = 0.001). The contemporary IAC and OC measures were found to be significantly lower on both sides compared to the skulls from the other three eras (p < 0.001 for both). CONCLUSIONS: Although no significant change was observed in PSV, decreases were evident in TBP, OC width and IAC length and width over time. It appears a fair inference that changes in size of OC and IAC might be another indication of the fact that olfaction and hearing were more vital for survival in old eras. Since we do not know incidence of chronic ear problems in old eras, we cannot speculate outcome of increased TBP in terms of developing chronic ear diseases. On the contrary, increased TBP was likely to play a protective role in traumas in old ears. Additionally, the environmental influences may be crucial role in the development of paranasal sinuses.

Artificial Intelligence for Otosclerosis Detection: A Pilot Study.

The gold standard for otosclerosis diagnosis, aside from surgery, is high-resolution temporal bone computed tomography (TBCT), but it can be compromised by the small size of the lesions. Many artificial intelligence (AI) algorithms exist, but they are not yet used in daily practice for otosclerosis diagnosis. The aim was to evaluate the diagnostic performance of AI in the detection of otosclerosis. This case-control study included patients with otosclerosis surgically confirmed (2010-2020) and control patients who underwent TBCT and for whom radiological data were available. The AI algorithm interpreted the TBCT to assign a positive or negative diagnosis of otosclerosis. A double-blind reading was then performed by two trained radiologists, and the diagnostic performances were compared according to the best combination of sensitivity and specificity (Youden index). A total of 274 TBCT were included (174 TBCT cases and 100 TBCT controls). For the AI algorithm, the best combination of sensitivity and specificity was 79% and 98%, with an ideal diagnostic probability value estimated by the Youden index at 59%. For radiological analysis, sensitivity was 84% and specificity 98%. The diagnostic performance of the AI algorithm was comparable to that of a trained radiologist, although the sensitivity at the estimated ideal threshold was lower.

The Role of Temporal Bone Pneumatization on Fracture Line and Involved Cranial Structures.

OBJECTIVE: Temporal bone pneumatization (TBP) is speculated to serve as a shock absorber in temporal bone fractures (TBF), directing the fracture line away from vital structures. This study correlates TBP extent with TBF patterns and preservations of vital TB structures. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary referral medical center. METHODS: All TBF patients referred to a single tertiary center 2017 to 2023 were evaluated. A pneumatization index score for each of their TBs was derived by counting automated-voxel density in a 0 to 100 scale. Results were correlated to the TBF type and the violated structure(s). The ossification index was compared to previously detailed qualitative classification systems of TBP. RESULTS: One hundred and forty-five patients were enrolled (mean age 43 ± 17 years). Kinematics were motor vehicle accidents (46%), scooter (15%), bicycle (14%), falls (13%), and assaults (8%). The mastoid ossification index we used showed a strong correlation to all qualitative classification systems (sigmoid = 0.829; labyrinthine = 0.849; carotis = 0.863, infralabyrinthine = 0.869, all P < .001). The pneumatization index strongly correlated with capsule-violating TBFs, with a mean of 44 ± 23 for otic capsule-sparing TBF and 61 ± 20 for otic capsule-violating (OCV) TBF (P < .001). The facial nerve was violated in 30 patients. Facial canal (FC) involvement was not correlated to the ossification index: it was 49 ± 23 for FC-sparing and 44 ± 23 for FC-violating (P = .620). CONCLUSION: TBP serves as a protective mechanism against OCV TBF. The more pneumatized the TB, the less likely the otic capsule will be violated in the event of a TBF with the exception of the carotid and FCs. TBP index is in strong agreement with qualitative TBP classification systems.

Cranial Rosai-Dorfman disease: a case report and literature review.

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.

Temporal bone remodeling is an indicator of transverse sinus stenosis on computed tomography.

PURPOSE: The purpose of this study was to identify potential association between transverse sinus stenosis (TSS) and temporal bone thinning downstream of TSS on computed tomography (CT). MATERIALS AND METHODS: Clinical and radiological data of patients with venous pulsatile tinnitus due to TSS (TSS group) and treated with stenting from 2019 to 2022 were retrospectively collected. An age-matched control group of patients with venous or neutral pulsatile tinnitus (control group) was built. CT measurements of temporal bone thickness were performed at the level of transverse-sigmoid sinus junction (E1) and the occipitomastoid suture (E2). E1; E2 and E1/E2 ratios obtained in TSS and control groups were compared. RESULTS: A total of 122 patients with venous pulsatile tinnitus were included. There were 56 patients with TSS (TSS group; 56 women; mean age, 35.5 ± 11.3 [standard deviation] years) and 66 patients without TSS (control group; 54 women; mean age, 37.7 ± 10.5 [standard deviation] years). E1 measurements and E1/E2 ratios on the symptomatic and dominant sides were significantly lower in the TSS group by comparison with the contralateral side of the same group (P < 0.05) and the ipsilateral side of the control group (P < 0.05). There were no differences in median E2 values between the TSS group (6.8 mm; range: 3.5-10.8 mm) and the control group (7.1 mm; range: 2.9-11.2 mm) (P = 0.098). E1 = 0 mm was found only in the TSS group. At receiver operating characteristic (ROC) analysis, an E1/E2 ratio threshold of 0.562 maximized the ability to predict presence of TSS. An E1/E2 ratio < 0.562 was predictive of symptomatic TSS with an accuracy of 74% (95% confidence interval: 65-82%). The AUC for the diagnosis of TSS was 0.807 (95% CI: 0.729-0.885). CONCLUSION: Temporal bone thickness is significantly reduced downstream of the stenosis on the pulsatile tinnitus side and may be a good indicator of symptomatic TSS.

Squamous cell carcinoma of ear and temporal bone: A retrospective study on clinicopathological predictors.

BACKGROUND: Ear and temporal bone squamous cell carcinoma (ETBSCC) is a rare and aggressive malignant tumor with minimal clinicopathological studies. The object of this study was to retrospectively evaluate the predictive effect of clinicopathological variables on the 5-year overall survival (OS) rate of ETBSCC patients in a single tertiary medical center in Tianjin, China. METHODS: A cohort of 44 patients with diagnosed ETBSCC from December 2012 to August 2022 were retrospectively studied. Univariate and multivariate analysis were, respectively, performed for the assessment of clinicopathological predictors, including sex, age, history of chronic suppurative otitis media (CSOM), lesion side, diameter, the choice of surgical approach, parotidectomy, neck dissection, adjuvant therapies, T stage, lymph node metastasis, tumor grade, margin, perineural invasion (PNI), and Ki-67 index. RESULTS: Seventeen females and 27 males were included, with the mean age of 65 years old, ranging from 36 to 89 years. The 5-year OS rate was 43% (mean 51 months, 95% confidence interval [CI] = 39-64). Significant prediction of a worse prognosis for 5-year OS rate was observed under univariate analysis for advanced T stage, positive margin, identified PNI, and higher Ki-67 index, respectively. Advanced T stage was confirmed to be an independent prognostic factor strongly affecting 5-year OS rate among this cohort of patients using a multivariate cox proportional hazard model. CONCLUSION: We found that clinicopathological parameters, especially postoperative pathological parameters, play a critical role in predicting the prognosis of ETBSCC patients.

Anatomical and Radiological Analysis of Structures of Petrous Part of the Temporal Bone and Their Impact on Area of Anterior Petrosectomy.

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.

Three-dimensional replica of the temporal bone in the teaching of human anatomy.

PURPOSE: The current study proposes the comparison of the visualization and identification of anatomical details between natural human temporal bone, its respective copy from three-dimensional printing, and the virtual model obtained from CBCT. METHODS: The sample consisted of undergraduate students in Dentistry (Group UE, n = 22), Postgraduate students in Radiology and Imaging (Group P-RI, n = 20), and Postgraduate students in Forensic Odontology (Group P-FO, n = 24). All participants attended a theoretical class on specialized anatomy of the temporal bone and subsequently performed the markings of 10 determined structures. RESULTS: The number of correct identifications was similar in natural bone and printed three-dimensional models in all groups (p > 0.05). The virtual model showed a significantly lower number of correct structures (p < 0.05) in the 3 groups. In general, there were significantly higher percentages of accurate answers among postgraduate students compared to undergraduate students. Most graduate students believed that the printed three-dimensional model could be used to teach anatomy in place of natural bone, while undergraduate students disagreed or were unsure (p < 0.05). Regarding the virtual tomographic image, in all groups, students disagreed or were not sure that its use would be beneficial in replacing natural bone. CONCLUSION: Three-dimensional and virtual models can be used as auxiliary tools in teaching anatomy, complementing practical learning with natural bones.

Exploration of different electrode types inserted in a 3D model of a patient with incomplete partition type III inner ear malformation.

BACKGROUND: Incomplete partition type III (IP III) represents a rare malformation of the inner ear, posing challenges during cochlear implantation due to inevitable cerebrospinal fluid (CSF) leaks and the potential misplacement of electrodes within the internal auditory canal (IAC). Despite the absence of a consensus on electrode selection, literature suggests both straight and perimodiolar electrodes as viable options for proper insertion. Limited implantation series contribute to the ambiguity in electrode choice. In this study, we evaluated the insertion performance of three electrode types in a 3D model simulating an IP III patient's inner ear. METHODS: A 3D model replicating the inner ear of a patient with IP III undergoing surgery was created, incorporating a canal wall up mastoidectomy and an enlarged round window approach. Insertions were carried out using a straight electrode, a perimodiolar electrode, and a slim perimodiolar electrode, inserted through a sheath in the basal turn of the cochlea. Electrode positions were assessed after each insertion, with each type being tested 20 times. RESULTS: Successful insertion rates were 95 % for the slim perimodiolar electrode, 85 % for the perimodiolar electrode, and 75 % for the slim straight electrode. Notably, the slim perimodiolar electrode required an adapted insertion technique due to the altered cochlear position in IP III cases. Statistical analysis revealed the slim perimodiolar electrode's superiority over the slim straight electrode in achieving successful insertions. CONCLUSIONS: The 3D model of the IP III inner ear proved to be an effective tool for electrode testing and insertion training prior to surgery. Following multiple insertions in the 3D model, the slim perimodiolar electrode demonstrated the highest success rate, emphasizing its potential as the preferred choice for cochlear implantation in IP III cases.

Spontaneous Intraventricular Tension Pneumocephalus.

Here, we report a very rare case of spontaneous intraventricular tension pneumocephalus. This case concerns a 40-year-old patient with medical history of a tumor of the pineal region and a secondary hydrocephalus treated by multiple ventriculoperitoneal shunts. He presented in the emergency room because of unusual headaches, nausea, and visual loss. In addition, he reported slight rhinorrhea in the past few weeks. The initial brain computed tomography scan revealed a spontaneous intraventricular tension pneumocephalus. There was no history of recent head trauma and no sign of disconnection of the shunt system. A complementary radiologic assessment including a thin-slice bone computed tomography scan and a radioisotope cisternography revealed an osseous defect and an isotope leakage at the junction between the tegmen tympani and the squamous part of the left temporal bone. A middle cranial fossa surgery was performed to repair the osteo-meningeal breach.

Pediatric cerebrospinal fluid rhinorrhea caused by low flow vascular anomaly of the temporal bone: A case series.

OBJECTIVE: Atraumatic cerebrospinal fluid (CSF) rhinorrhea is uncommon in children and necessitates a multi-disciplinary evaluation for an etiology. Underlying osseous abnormality due to extensive or multifocal low flow vascular anomaly should be considered as a potential cause of spontaneous CSF leak. Treatment of multifocal low flow vascular anomalies may include medical and surgical approaches. In this series, we seek to determine the presenting signs and symptoms and medical and surgical treatment options for multifocal or extensive low flow vascular anomalies. METHODS: A retrospective case series at a quaternary care children's hospital was compiled. All children with CSF rhinorrhea diagnosed and treated for multifocal low flow vascular anomalies at our institution were included. A total of four patients were identified. RESULTS: All four patients had delay in initial diagnosis of underlying cause of meningitis and CSF rhinorrhea. Average age at diagnosis of multifocal low flow vascular anomaly was 7 years. This was on average 4 years after initial presentation for medical attention. Treatment approach was multidisciplinary and included medical management with sirolimus and bisphosphonates as well as surgical approaches to the skull base (lateral and anterior) to prevent CSF egress. CONCLUSION: Consideration of multifocal low flow vascular anomaly should be included in any pediatric patient presenting with CSF rhinorrhea.

Simulated Injuries of the Sheep Ossicular Chain: Correlations With Their Radiological Images.

Hypothesis We hypothesized that a sheep temporal bone would be a suitable model to study correlations between simulated middle ear injuries and their radiological appearances. Simulated ossicular chain injuries correlate well with their radiological images, and post-processing techniques provide optimal visualization of the sheep ossicles. Background The subtle ossicular trauma may be difficult to assess due to the small size of the structures. The precise radiological and clinical correlations of the ossicular injuries are not well documented. Methods The most common traumatic ossicular chain injuries were systematically simulated in the sheep temporal bone model. The images of the temporal bones were obtained with a high-resolution computed tomography scanner. The values of the dislocations were measured from the obtained images as well as in the temporal bones using calipers. Two observers independently evaluated the fine structures of the auditory ossicles using oblique multiplanar reconstructions (MPRs) and maximum intensity projections (MIPs). All segments of the facial nerve were also visualized. Results Optimal visualization planes of the sheep's middle ear joints have been obtained. The coincidence of simulated ossicular injuries in the specimens and MIPs was 40%. All structures of the ossicular chain were clearly distinguished except for the stapes footplate. Evaluation of the traumatic changes of the incudostapedial joint was challenging. Conclusions The sheep temporal bone is a suitable model for studying the correlations between pathological alterations in the ossicular chain and their radiological appearances. The post-processing MIP technique provides a more accurate and easier diagnosis of traumatic ossicular chain injuries than MPRs alone.