Facial Canal Research Articles

What is the most important factor to preserve hearing in lateral semicircular canal fistula surgeries, fistula size or bony structure?

Cholesteatoma on lateral semicircular canal (LSCC) fistula > 2mm in size is likely to be unmanipulated due to the risk of sensorineural hearing loss. However, the matrix can be successfully removed without hearing loss when it is > 2mm. The purpose of the study was to evaluate surgical experience over the past 10years and to suggest the important factor for the hearing preservation in LSCC fistula surgeries. According to the fistula size and symptoms, 63 patients with LSCC fistula were grouped as follows: Type I (fistula < 2mm), Type II (≥ 2mm and < 4mm without vertigo), Type III (≥ 2mm and < 4mm with vertigo), Type IV (≥ 4mm), and Type V (any size fistula but with deafness at the initial visit). The cholesteatoma matrix was meticulously manipulated and removed by experienced surgeons. Only two patients completely lost their hearing after surgery (4.5%). However, the loss was inevitable because their cholesteatomas were highly invasive and there was also facial nerve canal involvement; thus, the bony structure of the LSCC was already destroyed by the cholesteatoma. Unlike these two Type IV patients, Type I-III patients, and those with a fistula size < 4mm, did not lose their sensorineural hearing. If the structure of the LSCC was maintained, hearing loss did not occur even if the fistula size ≥ 4mm. The preservation of the labyrinthine structure is more important than the defect size of the LSCC fistula. If the structure is intact, cholesteatoma matrices lying on the defect can be safely removed, even though the size of bony defect is large.

Drilling accuracy evaluation of a mouldable surgical targeting system for minimally invasive access to anatomic targets in the temporal bone.

Minimally invasive cochlear implant surgery using a micro-stereotactic surgical targeting system with on-site moulding of the template aims for a reliable, less experience-dependent access to the inner ear under maximal reduction of trauma to anatomic structures. We present an accuracy evaluation of our system in ex-vivo testing. Eleven drilling experiments were performed on four cadaveric temporal bone specimens. The process involved preoperative imaging after affixing the reference frame to the skull, planning of a safe trajectory preserving relevant anatomical structures, customization of the surgical template, execution of the guided drilling and postoperative imaging for determination of the drilling accuracy. Deviation between the drilled and desired trajectories was measured at different depths. All drilling experiments were successfully performed. Other than purposely sacrificing the chorda tympani in one experiment, no other relevant anatomy, such as facial nerve, chorda tympani, ossicles or external auditory canal were harmed. Deviation between the desired and achieved path was found to be 0.25 ± 0.16mm at skulls' surface and 0.51 ± 0.35mm at the target level. The closest distance of the drilled trajectories' outer circumference to the facial nerve was 0.44mm. We demonstrated the usability for drilling to the middle ear on human cadaveric specimen in a pre-clinical setting. Accuracy proved to be suitable for many applications such as procedures within the field of image-guided neurosurgery. Promising approaches to reach sufficient submillimetre accuracy for CI surgery have been outlined.

Outcomes of canal wall down mastoidectomy in cholesteatoma: a 5-year experience

BackgroundCholesteatoma is an atticoantral disease that potentially causes life-threatening complications. Therefore, canal wall down mastoidectomy is a well-established technique to eradicate the disease, especially in extensive cholesteatoma.AimTo evaluate the status of dry ear and hearing outcome post-retrograde canal wall down mastoidectomy.MethodsA retrospective study of patients with cholesteatoma who underwent modified radical mastoidectomy (MRM), a form of canal wall down mastoidectomy between January 2014 and December 2018.ResultsFifty-seven patients were included with a mean age of 40 years. The majority of cases were adults, 86%, and 14% were children. Most of them complained of ear discharge (73.7%), followed by hearing loss (31.6%). Intraoperatively, cholesteatoma was primarily found in cases involving mastoid air cells, antrum, attic, and mesotympanum (47.4%). The presence of granulation tissue with cholesteatoma was noted in 57.9% of cases. Furthermore, 73.7 % of ossicular chain erosion cases involved erosion of all ossicles (47.6 %). In 26.3 % of cases, tegmen erosion was identified. Facial canal dehiscence accounted for 15.8% of MRM cases, sclerotic mastoid was noted for 10.5%, and lateral semicircular canal dehiscence involved 5.3%. Up to 3 months of follow-up post-MRM showed 70.2% had a dry ear. After 6 months, there were 15.8% complaints of ear discharge in the subsequent follow-up. In this study, 33 out of 57 patients underwent a postoperative hearing evaluation, and 21.2 % of patients showed an improvement in the air-bone gap.ConclusionCanal wall down mastoidectomy is a treatment of choice in extensive cholesteatoma to achieve a dry and safe ear with maintaining functional hearing outcomes.

THE RATIO OF THE LENGTH OF THE LABYRINTH SEGMENT TO THE LENGTH AND WIDTH OF THE SKULL IN VARIOUS CRANIOTYPIC FORMS OF THE SKULL

The aim of the study was to study the ratio of the length of the labyrinthine part of the facial canal to the length and width of skulls with different cranial indices, as well as different age groups. Material and methods. The material for the study was 133 tomograms taken from the archives of the radiological department and the department of radiation diagnostics and therapy of the Educational and Surgical Clinic of the Azerbaijan Medical University. The material is divided according to age groups. All skulls are divided into brachiocranes (80.0 and above), dolichocranes (74.9 and below) and mesocranes (75.0-79.9) according to the cranial index. The length of the labyrinth segment of the facial canal was measured in the axial (sagittal) and coronal projections of the tomogram slices. Research results. Comparison of the ratio of the length of the labyrinth segment to the length of the skull between age groups shows that the difference is significant on the right side (PH=0.024) in brachiocranial skulls and on the left side (PH=0.008) in dolichocranial skulls. In mesocranial skulls, this ratio does not have significant differences. The difference in the ratio of the length of the labyrinth segment to the width of the skull is also noted on the right in brachiocranial skulls and on the left in dolichocranial skulls. Statistical analysis of this indicator did not reveal a significant difference in mesocranial skulls. Conclusions. Thus, the difference in the ratio of the length of the labyrinth segment to the length and width of the skull revealed asymmetry, which was on the right side of the skulls of the brachiocranial type and on the left side of the dolichocranial type. In mesocranial-type skulls, statistical differences in these parameters were not found either in age groups or on the right and left sides.

Surgical issues and managements in cochlear reimplantation in 32 children

Objective:To summarize the clinical characteristics of children undergoing surgery of cochlear reimplantation, focus on various problems and management in cochlear reimplantation, in order to avoid related problems in surgery of cochlear reimplantation and the initial implantation. Methods:A total of 32 children who underwent cochlear reimplantation in Peking University Third Hospital from July 2018 to July 2022 were retrospectively analyzed, and the duration from the initial implantation was from 1 year to 8 years. The cochlear implant mapping was performed 4 weeks after the operation, and the auditory performance was evaluated. Results:Special intraoperative issues included 32 cases with bone and soft tissue hyperplasia at various sites（2 cases with obvious bone hyperplasia in cochlear window, 1 case with obvious bone hyperplasia in subperiosteal tunnel of wire）, 5 cases with bone defects in important structures（including the posterior wall of the external auditory canal, the facial nerve canal, and the subperiosteal pocker of the receiver-stimulator）, 1 case with cholesteatoma, 4 cases with other lesions or foreign bodies, 4 cases with abnormal position of the electrodes（migration or reversal）. All operations were successfully completed without complications. Postoperative recoveries were smooth. Conclusion:In the initial cochlear implantation, attention should be paid to retain residual hearing as much as possible, fully consider the possibility of postoperative bone hyperplasia, avoid large amounts of non-absorbable adhesive materials, avoid bone defects in important structures（such as facial nerve canal or posterior wall of the external auditory canal）, pay attention to the depth and orientation of electrode implantation. The possibility of "hidden injury" mentioned above should be fully considered in surgery of cochlear reimplantation to avoid new injury or complication.

Surgical and nonsurgical treatment outcomes in traumatic facial nerve palsy.

Facial nerve decompression surgery is performed on patients with immediate, complete traumatic facial palsy. However, the clinical advantage of the surgical treatment has weak evidence because of lack of control groups in previous studies. Therefore, this study compared facial function outcomes between the patients who underwent surgery and those who did not. Furthermore, in cases of bilateral traumatic facial palsy, the outcomes of the surgical and nonsurgical sides were also discussed. A retrospective medical chart review of immediate and severe (House-Brackman [HB] grade V and VI) traumatic facial palsy was conducted. Twenty-five ears from the surgical group and eight ears from the conservative treatment group were enrolled. Among the patients, three with immediate and severe bilateral facial palsy underwent unilateral surgery. The average HB grade after 1-year follow-up was 1.7 in the surgical group and 1.5 in the nonsurgical group. Four patients who have definite facial canal disruption in the imaging study have recovered to HB grades I-III without surgical intervention. In patients with bilateral facial palsy, the nonsurgical side showed the same or better facial functions than the surgical side. Compared with nonsurgical conservative treatment, facial nerve decompression surgery did not show superior outcomes in immediate HB grade V-VI traumatic facial palsy. The clinical advantage of facial nerve decompression is questionable and should be re-evaluated in a prospectively designed study.

Evaluation of the Morphometry of the Stylomastoid Foramen in the Turkish Population: A Retrospective Study Using Cone-Beam Computed Tomography (CBCT).

Objectives This study aimed to investigate the morphometric features of the stylomastoid foramen (SMF) and the facial canal in the Turkish population using cone-beam computed tomography (CBCT) retrospectively. Methods The randomly selected 479 patients aged from 8 to 87 years were examined, and a total of 958 CBCT images of the SMF and facial canal (FC) were analyzed. The diameter of the SMF and FC at the mastoid segment and their relation to age, gender, and side were evaluated. Statistical analyses were performed using Kolmogorov-Smirnov, one-way analysis of variance, Student's t -test, chi-squared test, Tukey's honestly significant difference, and Fisher-Freeman-Halton exact test. p -Values < 0.05 were accepted as statistically significant at the 95% confidence interval. Results The mean age of the patients was 40.49 ± 19.73 years. The mean diameter of the right SMF was 2.24 ± 0.58 and 2.50 ± 0.63 mm in females and males. The mean diameter of the left SMF was 2.25 ± 0.56 and 2.44 ± 0.62 mm in females and males. The mean diameter of the right FC was 1.60 ± 0.35 and 1.70 ± 0.34 mm in females and males. The mean diameter of left FC was 1.55 ± 0.35 and 1.66 ± 0.33 mm in females and males. A statistically significant difference was found between the age groups in terms of the mean SMF and FC diameter on both sides ( p < 0.05). Conclusion Information obtained from this study regarding the morphometric features of the SMF and thereby FC may assist surgeons in treatment plans and reduce the risk of neurosurgical complications.

Three-dimensional structure of the facial canal and related blood vessels and nerves in the temporal bone.

There are only limited anatomical data on nerves, veins, and arteries in the temporal bone. More detailed anatomical data are required to improve planning of treatments targeting the temporal bone region. Herein, we performed a detailed analysis of the facial canal (FC) and the related carotid artery and vein. We examined the bony structure of the middle ear and FC, jugular foramen, and carotid canal in 30 Japanese elderly donor cadavers. Three-dimensional reconstruction of the canal structure was achieved using cone beam computed tomography, while macroscopic and histological analyses were also performed. The FC form was classified as either straight (28%) or bent (72%). There were significant differences in the diameter of the FC and the distance between the internal jugular vein, other FC branches, and the FC. Principal component analysis (PCA) was performed for the FC using 29 factors. Two principal components significantly explained 30.9% (component 1, 18.6%; component 2, 12.3%) of the FC. Histological observation showed numerous ganglion cells and shrunken neurons in the geniculate ganglion of the facial nerve of elderly samples. FC diameter is an important contributor to the relationship between the FC and the jugular foramen. The FC and the internal jugular vein are located close to each other, which is useful information for the trans-canal surgery of the otology. Furthermore, the geniculate ganglion contains numerous ganglion cells and shrunken neurons, which may affect the FC structure during bone matrix remodeling with aging.

Relationship Between Facial Bone Fractures and the Risk of Posttraumatic Complications: A Hypothesis on the Cushion Effect of the Facial Skeletons in Temporal Bone Fractures.

This study investigated whether concomitant facial bone (FB) fractures reduce temporal bone (TB) injuries, such as posttraumatic facial palsy and vertigo, through an impact absorbing effect, so-called "cushion effect," in severe trauma patients. A total of 134 patients with a TB fracture were included. They were divided into two groups according to their concomitant facial fractures: group I (no FB fracture) and group II (FB fracture). We compared clinical characteristics, such as brain injury, trauma severity, and complications of TB fracture, between the two groups. In group II, immediate facial palsy was more frequent (11.6% vs. 1.5% in group I), and the Injury Severity Score was higher (19.0 ± 5.9 vs. 16.7 ± 7.3, P = 0.020). Delayed facial palsy (12.3% in group I vs. 4.3% in group II) and posttraumatic vertigo (24.6% vs. 7.2%) occurred more often in group I. FB fractures significantly decreased the incidence of posttraumatic vertigo (odds ratio [OR], 0.276; 95% confidence interval [CI], 0.083-0.914). Intraventricular hemorrhage (OR, 20.958; 95% CI, 2.075-211.677), facial nerve canal injury (OR, 12.229; 95% CI, 2.465-60.670), and FB fractures (OR, 16.420; 95% CI, 1.298-207.738) increased the risk of immediate facial palsy. Concomitant FB fractures reduced the risk of the occurrence of delayed facial palsy and posttraumatic vertigo in injured patients with TB fracture. Particularly, an anterior force may be reduced by the cushion effect of the bony fracture.

An Exploratory Study of High Resolution Computed Tomography of Temporal Bone in Chronic Otitis Media

Introduction: Among various modalities used in the evaluation of chronic otitis media, HRCT of the temporal bone is the most reliable and valuable imaging modality as it provides excellent anatomic information. It can display minute anatomical and pathological details by providing a direct visual window into the temporal bone. Methods: This is a prospective cross-sectional study done at the department of Radiodiagnosis and imaging of Birat Medical College, Teaching hospital over 1 year with a total of 50 patients enrolled in the study. The findings were compared with the post-operative findings and data were entered. HRCT was done on 64 slices of multidetector CT scan. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of various parameters were calculated. Results: Out of 50 patients were enrolled in this study. Among them 52%(26) were females and 48%(24) were males. HRCT showed 100% sensitivity for the lateral semicircular canal and sigmoid plate erosion. The sensitivity and specificity of cholesteatoma were 79.06% and 42.85% respectively. It also offered a sensitivity of 75% and 95% for the erosion of the facial nerve canal and tegmen tympani respectively Conclusions: High-resolution computed tomography is a reliable diagnostic tool for the pre-operative evaluation of chronic otitis media. It helps the operating surgeon to evaluate the anatomical extent of the disease process and aids in the surgical approach that helps prevent probable complications during surgery

Utilization of computed tomography in pediatric temporal fractures: A dose reduction approach

Objectives1)Determine the sensitivity and specificity of CT brain to detect temporal bone fractures.2)Calculate the additional ionizing radiation exposure incurred from a TBCT. MethodsRetrospective chart review was performed of pediatric patients who underwent CT brain as part of a trauma pan-scan and dedicated temporal bone CT in the setting of head trauma. The original CT images were re-reviewed by two board certified Neuroradiologists in a blinded manner to determine the presence or absence of temporal bone fracture and if present, fracture line involvement of the 5 critical temporal bone anatomic structures. The dose length product (DLP), a measure of approximate total radiation dose delivered during CT scan (mGy-cm), was noted from the data available. ResultsThere were 24 temporal bone fractures in a total of 29 patients (4 with bilateral fractures). There were 21 of 24 fractures that were correctly identified on trauma pan-scan CT with dedicated temporal bone CT considered as the diagnostic gold standard. There was a combined sensitivity and specificity of 91 % and 100 % respectively. The sensitivity and specificity in identifying involvement of critical structures were as follows: carotid canal (100 % and 100 %); ossicular chain (75 % and 100 %); tegmen tympani (60 % and 97.9 %); facial nerve canal (25 % and 100 %); otic capsule (N/A and 98.5 %). The median DLP for trauma pan-scan CT and temporal bone CT were 627 mGy-cm and 267 mGy-cm respectively. ConclusionDedicated TBCT is not required to accurately diagnose and characterize temporal bone fractures seen on trauma pan-scan CT. The radiation exposure of concurrent or subsequent dedicated temporal bone imaging is equal to approximately one half of the original trauma pan-scan CT.

Improved Prediction of Hearing Loss after Temporal Bone Fracture by Applying a Detailed Classification for Otic Capsule-Violating Fracture: A Wide Scope Analysis with Large Case Series.

This study aimed to analyze the predictability of temporal bone (TB) fracture-associated hearing loss by applying a detailed classification separating individual injury of the cochlea, vestibule, and semicircular canals (SCC). In this retrospective study, patients with otic capsule-violating (OCV) fractures were further classified as OCV-C(VS) when the cochlea was involved regardless of vestibule or SCC involvement, OCV-V(S) when the vestibule was involved regardless of SCC involvement, and OCV-S when the fracture only involved SCC. Hearing changes were compared by applying the above-mentioned classification, and TB fracture-induced facial palsy was also analyzed. A total of 119 patients were included. Patients with OCV fractures had significantly worse bone conduction (BC) and air conduction (AC) thresholds (59.1 ± 25.3 and 87.0 ± 29.5 dB) than those with otic capsule-sparing (OCS) fractures (20.1 ± 17.9 and 36.5 ± 21.9 dB; p < 0.001 for each comparison). The BC and the AC thresholds of OCV-C(VS) (77.5 ± 11.0 and 114.2 ± 14.3 dB) and OCV-V(S) (69.3 ± 27.7 and 98.0 ± 22.2 dB) were significantly higher than OCV-S (40.1 ± 22.9 and 62.1 ± 25.6 dB; p < 0.001 for each comparison). The BC hearing thresholds were not significantly improved in the last pure tone audiometry when compared for total, OCV, or OCS cases. The AC threshold significantly improved in OCS cases. In a considerable number of cases with facial palsy, causative fracture lines involved the geniculate ganglion or tympanic segment without the involvement of the otic capsule. Most cases showed significant improvement; however, recovery was limited in cases with obvious fallopian canal disruption. The cases with sole involvement of SCC had significantly better hearing thresholds than those with cochlear or vestibule involvement, even in OCV fracture cases.

Facial canal dehiscence in patients undergoing surgery for chronic otitis media: analysis of 850 patients.

ntroductionIn all otologic surgeries, the facial nerve can be considered the most important structure that must be protected. The surgical damage risk of the facial nerve will be increased in presence of facial canal dehiscence (FCD).AimIn this study, we aimed to evaluate the FCD and its associated situations in patients with chronic otitis media undergoing mastoidectomy.Materials and Methods850 patients who performed ear surgery were reviewed. Patients who did not perform mastoidectomy were excluded. In patients, the ratios, localization of FCD, and association of facial canal dehiscence with cholesteatoma were researched. Association between FCD and closed-cavity tympanomastoidectomy, open-cavity tympanomastoidectomy, and radical mastoidectomy procedures, and also an association between FCD and primary or revision surgery was evaluated. ResultsFacial canal dehiscence was found in 8.4% of patients. The relationship between dehiscence and cholesteatoma was found significant (p&lt;0.001). In the comparison of radical mastoidectomy and closed-cavity tympanomastoidectomy, dehiscence was higher in the radical mastoidectomy group (p&lt;0.03). In revision cases, dehiscence was seen more frequently (p&lt;0.003). FCD incidence was higher in adult patients than in pediatric patients (p&lt;0.001). Twenty of 468 patients who were operated on for cholesteatoma had congenital cholesteatoma. ConclusionFacial canal dehiscence can be seen especially in cases with cholesteatoma and when performing radical mastoidectomy and revision surgeries. Therefore, a detailed evaluation of the status of facial nerve and determination of situations in which occurrence of FCD is more likely both preoperatively and intraoperatively will minimalize potential complications.Keywords: Cholesteatoma, tympanic, radical mastoidectomy, oval window, tympanomastoidectomy.

Effect of the vertical facial canal to round window distance concerning neural response telemetry during cochlear implantation in children.

To assess the correlation of the distance from the round window (RW) to the vertical facial canal (VFC) with neural response telemetry thresholds (T-NRT), which may have an influence on the insertion trajectory and aid in preoperative surgical planning and electrode selection. An observational study was conducted on 30 prelingually deaf children under five years diagnosed with bilateral severe to profound hearing loss and received a cochlear implant. The preoperative high resolution computed tomography (HRCT) images in the axial cut bone window setting at the round window level was used to calculate the distance from the RW to the VFC on the RadiAnt DICOM Viewer. The intraoperative distance was measured with ScopyDoc version 8.2.4 software. In Auto-NRT mode, software-based recordings (Cochlear's Custom Sound EP 6.0) were used to measure and evaluate the T-NRT current level. A statistically significant positive correlation of the RW to VFC distance with the average T-NRT p=0.02, r=-0.4 and with the mid-frequency, T-NRT p=0.003, r=-0.5 was found. The insertion trajectory can be ascertained by a statistically significant correlation between average T-NRT and mid-frequency T-NRT with RW and VFC distance, and this reliable factor can be taken into account in future surgical technique modulation, electrode selection, and electrode design.

Facial nerve stimulation in adult cochlear implant recipients with far advanced otosclerosis.

The objective of this study was to predict occurrence of facial nerve stimulation (FNS) in cochlear implanted patients for far-advanced otosclerosis (FAO) by correlating preoperative computed tomography (CT)-scan data to FNS and to evaluate FNS impact on hearing outcomes. Retrospective analysis on 91 ears (76 patients) implanted for FAO. Electrodes were straight (50%) or perimodiolar (50%). Demographic data, extension of otosclerosis on preoperative CT scan, occurrence of FNS, and speech performance were analyzed. Prevalence of FNS was 21% (19 ears). FNS appeared during the first month (21%), 1-6months (26%), 6-12 months (21%), and over 1year (32%) postimplantation. Cumulative incidence of FNS at 15 years was 33% (95% CI=[14-47%]). Extension of otosclerotic lesions on preimplantation CT-scan was more severe in FNS ears compared to No-FNS (p < .05): for Stage III, 13/19 (68%) and 18/72 (25%) ears for FNS and No-FNS groups, respectively (p < .05). Location of otosclerotic lesions relative to the facial nerve canal was similar whatever the presence or not of FNS. Electrode array had no impact on FNS occurrence. At 1 year post-implantation, duration of profound hearing loss (≥5 years) and previous stapedotomy were negatively associated with speech performance. FNS did not impact hearing outcomes, despite a lower percentage of activated electrodes (p < .01) in the FNS group. Nevertheless, FNS were associated with a decrease of speech performance both in quiet (p < .001) and in noise (p < .05). Cochlear implanted patients for FAO are at greater risk of developing FNS affecting speech performance over time, probably due to a higher percentage of deactivated electrodes. High resolution CT-scan is an essential tool allowing FNS prediction but not time of onset. 2b, Laryngoscope Investigative Otolaryngology, 2022.

A novel imaging scoring method for identifying facial canal dehiscence: an ultra-high-resolution CT study

ObjectivesFacial canal dehiscence (FCD), typically found in the tympanic segment, is a risk factor for facial nerve injury. An imaging scoring method was proposed to identify FCD based on ultra-high-resolution CT.MethodsForty patients (21 females and 19 males, mean age 44.3 ± 17.4 years), whose tympanic facial canal (FC) was examined during otological surgery, were divided into the FCD group (n = 29) and the control group (n = 11) based on surgical findings. Imaging appearance of tympanic FC was scored 0–3: 0 = no evident bony covering, 1 = discontinuous bony covering with linear deficiency, 2 = discontinuous bony covering with dotted deficiency, and 3 = continuous bony covering. Both lateral and inferior walls were assigned a score as LFCD and IFCD, respectively. An FCD score was calculated as LFCD + IFCD. The diagnostic value of the FCD score was tested using the ROC curve.ResultsThe inter-observer agreement was moderate for the lateral wall (Cohen’s κ coefficient 0.416, 95% CI 0.193–0.639), and good for the inferior wall (Cohen’s κ coefficient 0.702, 95% CI 0.516–0.888). In the FCD group, the most common appearance for both walls was discontinuous bony covering with linear deficiency (LFCD = 1, 22/29, 75.9%; IFCD = 1, 15/29, 51.7%). An FCD score of less than 4 was associated with high sensitivity (0.82) and specificity (0.93) for identifying FCD, with an AUC of 0.928.ConclusionsUsing the proposed scoring method, FCD score < 4 could identify FCD of the tympanic segment with high concordance with surgical findings.Key Points• Imaging appearance of the tympanic facial canal (FC) is divided into four types based on ultra-high-resolution CT images.• The most common appearance of FC with facial canal dehiscence (FCD) is discontinuous bony covering with linear deficiency.• An FCD score, consisting of scores of the lateral and inferior walls, less than 4 is highly indicative of FCD.

Comparison of High-Resolution Computed Tomography and Surgical Findings in Patients with Temporal Bone Cholesteatoma

Objective: The present study aims to investigate the role of high-resolution computed tomography (HRCT) in temporal bone cholesteatoma. Materials and Methods: Eighty-two patients with a pathological diagnosis of chronic otitis media with cholesteatoma were included in this retrospective study. All patients had a complete preoperative otorhinolaryngologic examination, audiological assessment, and HRCT. Preoperative radiological findings were evaluated together with the findings obtained during surgery. Results: In HRCT, cholesteatoma was most common in pars flaccida (36.25%). The most common localization of cholesteatoma was holotympanic (36.25%). Erosion was most common in all ossicles (43.75%), but solitary erosion was most common in the incus (35%). The facial nerve canal was intact in 58 (72.5%) of the patients. The diagnostic sensitivities of HRCT in cholesteatoma cases were 97.6% for tissue mass, 97.6% for localization, 100% for malleus erosion, 84.8% for incus erosion, 100% for malleus and incus erosion, 40% for incus and stapes erosion, 94.6% for the erosion of all ossicles, and 100% for facial nerve canal erosion. Conclusion: Preoperative HRCT evaluation in patients with cholesteatoma may be considered indispensable for the location of the disease and the detection of destructive structures.

A Study of Intraoperative Incidence of Fallopian Canal Dehiscence in Cases of Cholesteatoma.

Our study aimed to find the incidence of fallopian canal dehiscence during surgery for cholesteatoma, to compare this incidence with a homogenous control group (otosclerosis) and to find the incidence of a labyrinthine fistula if fallopian canal dehiscence is present. Prospective case control study design was used in the setting of a tertiary care referral center. Subjects included 60 patients. 30 patients diagnosed with cholesteatoma were taken as cases and 30 patients with conductive or mixed hearing loss suspected of otosclerosis were taken as controls. The method was identification of bony dehiscence under operating microscope. In case of finding of dehiscence of fallopian canal, presence of labyrinthine fistula was searched. The cases underwent modified radical mastoidectomy and controls underwent exploratory tympanotomy after giving a written informed consent. Institutional ethics committee clearance was obtained. Fallopian canal dehiscence was recorded in all subjects. 50% of cases and 3.3% of controls showed presence of fallopian canal dehiscence. This correlation was statistically significant (p < 0.001). Also 26.7% cases with fallopian canal dehiscence had a semicircular canal fistula (4 out of 15),but this finding was not significant (p = 0.100). From our study it was evident that there were very high chances of finding a fallopian canal dehiscence in cases of cholesteatoma than in cases undergoing exploratory tympanotomy. Also, presence of labyrinthine fistula with fallopian canal dehiscence was likely but not significant.

Labyrinthine Fistula in Chronic Otitis Media Surgery: Management and Outcomes.

The objective of this retrospective study was to present the experience on the management of labyrinthine fistula secondary to chronic otitis media in a tertiary center. 263 patients, who underwent tympanomastoidecomy, in Centro Hospitalar Universitário do Porto, between 2015 and 2020 were reviewed, to select only those with labyrinthine fistulas. 26 patients (9.89%) had cholesteatoma complicated by fistula of the lateral semicircular canal. Most frequent symptoms were unspecific, such as otorrhea, hearing loss and dizziness. Preoperative high-resolution computed tomography predicted fistula in 54%. Using the Dornhoffer and Milewski classification, 10 cases (38.46%) were identified as stage I, 15 (57.69%) at stage II, and 1 (3.85%) as stage III. The choice between open or closed surgical procedure was independent of the type of fistulae. The cholesteatoma matrix was completely removed from the fistula and immediately covered by autogenous material. In one patient matrix was left over the fistula. After surgery, hearing (bone conduction) was preserved or improved in 73% of the patients. There was no statistically significant relationship between the extent of the labyrinthine fistula, type of material used in fistula repair and the hearing outcome. Also, we didn't find a statistically significant relationship between extent of the labyrinthine fistula and the presence of facial nerve canal dehiscence, tegmen timpani erosion, sigmoid sinus exposure or ossicular bone erosions. In conclusion, a complete and nontraumatic removal of cholesteatoma matrix over the fistula in a single-staged procedure, is a safe and effective procedure, which achieves a hearing preservation or improvement in most cases.

Clinical Significance of Körner's Septum in Relation to Occurrence of Squamous Chronic Otitis Media.

The Körner's septum (KS), persistent petrosquamosal lamina, is a bony lamina (developmental remnant) that extends from the articular fossa to the mastoid apex, above the middle ear, and runs inferiorly and laterally to the facial nerve canal. The petrous and squamous bones meet at this septum. The anatomical structure of KS, which most frequently occurs at the level of the head of the malleus and/or the anterior semicircular canal, is described in depth in this work. The embryological elements of the temporal bone development that result in the formation of KS are taken into consideration. Clinically KS is consideredan important anatomical variation, in the development of chronic diseases of the ear like chronic otitis media, especially attic retraction pockets, and cholesteatoma as it can contributeto attic blockage. Also, studies have found a significant association between tympanosclerosis and KS. High-resolution computed tomography (HRCT) and cone-beam computed tomography are the two imaging methods most commonly used to identify KS. It is observed that KS was associated with an increased risk for chronic otitis media, and residual cholesteatoma. The purpose of this review article is to provide a general overview of the KS and its clinical implication, as well as to summarize and discuss the latest clinical data regarding this entity.