Temporal Bone Computed Tomography Research Articles

Prevalence of Superior Semicircular Canal Dehiscence in Coronal Images of Temporal Bone Computed Tomography and Its Diagnostic Value in Korean Population

Background and Objectives This study aimed to analyze the prevalence of superior semicircular canal dehiscence (SSCD) in the coronal images of high-resolution temporal bone computed tomography (TBCT) and to evaluate the diagnostic accuracy of coronal images for SSCD syndrome. Subjects and Method We retrospectively reviewed high-resolution TBCT scans of 217 patients (434 ears) with SSCD due to various causes. The dehiscence ratio (slices showing dehiscence/total slices showing the superior semicircular canal) in the coronal images of TBCT was calculated, and the optimal cutoff value for the diagnosis of SSCD syndrome was determined using the receiver operating characteristics (ROC) curve. Results Of the 434 ears, 64 (14.7%) presented SSCD in more than one slice of the coronal images of TBCT, but only three patients (0.7%) were confirmed with SSCD syndrome. Based on the ROC curve analysis for the dehiscence ratio of 64 ears, the optimal cutoff value for the diagnosis of SSCD syndrome was 0.67 with 100% sensitivity and 90.2% specificity. Conclusion The majority of cases diagnosed with SSCD syndrome using the coronal images of TBCT were asymptomatic or false-positive. The dehiscence ratio in the coronal images of TBCT combined with a typical symptom can be a highly sensitive and specific diagnostic tool for SSCD syndrome. Key words: Computed tomography ㆍ ROC curve ㆍ Semicircular canals

Augmented Reality of the Middle Ear Combining Otoendoscopy and Temporal Bone Computed Tomography.

Augmented reality (AR) may enhance otologic procedures by providing sub-millimetric accuracy and allowing the unification of information in a single screen. Several issues related to otologic procedures can be addressed through an AR system by providing sub-millimetric precision, supplying a global view of the middle ear cleft, and advantageously unifying the information in a single screen. The AR system is obtained by combining otoendoscopy with temporal bone computer tomography (CT). Four human temporal bone specimens were explored by high-resolution CT-scan and dynamic otoendoscopy with video recordings. The initialization of the system consisted of a semi-automatic registration between the otoendoscopic video and the 3D CT-scan reconstruction of the middle ear. Endoscope movements were estimated by several computer vision techniques (feature detectors/descriptors and optical flow) and used to warp the CT-scan to keep the correspondence with the otoendoscopic video. The system maintained synchronization between the CT-scan image and the otoendoscopic video in all experiments during slow and rapid (5-10 mm/s) endoscope movements. Among tested algorithms, two feature-based methods, scale-invariant feature transform (SIFT); and speeded up robust features (SURF), provided sub-millimeter mean tracking errors (0.38 ± 0.53 mm and 0.20 ± 0.16 mm, respectively) and an adequate image refresh rate (11 and 17 frames per second, respectively) after 2 minutes of procedure with continuous endoscope movements. A precise augmented reality combining video and 3D CT-scan data can be applied to otoendoscopy without the use of conventional neuronavigation tracking thanks to computer vision algorithms.

Determination of variations in temporal bone anatomical distances in CSOM and non-CSOM patients using computed tomography and intraoperative patient analysis

Tympanomastoidectomy surgery for chronic suppurative otitis media (CSOM) requires an understanding of the 3-dimensional anatomic structures of the middle ear. Although these structures can be evaluated radiologically, differences between CSOM and non-CSOM patients have not yet been determined, and the agreement between preoperative and intraoperative measurements has not been evaluated. This cross-sectional study was conducted at Cipto Mangunkusumo Hospital, Jakarta, Indonesia. The aim of this study was to evaluate differences in the temporal bone distances between CSOM and non-CSOM patients using computed tomography (CT) data from 30 consecutive cases and to evaluate the agreement between temporal bone distances measured using CT and intraoperative microscopy in 5 consecutive CSOM patients within a 9-month period. CSOM patients had smaller distances from the superior wall of the ear canal to two points on the tegmen, as well as a more acute sinodural angle and narrower aditus ad antrum. There was a good agreement between the temporal bone CT and intraoperative measurements of the distance from the posterior wall of the ear canal to the sigmoid sinus.

Prevalence of Extracochlear Electrodes: Computerized Tomography Scans, Cochlear Implant Maps, and Operative Reports.

To quantify and compare the number of cochlear implant (CI) electrodes found to be extracochlear on postoperative computerized tomography (CT) scans, the number of basal electrodes deactivated during standard CI mapping (without knowledge of the postoperative CT scan), and the extent of electrode insertion noted by the surgeon. Retrospective. Academic Medical Center. Two hundred sixty-two patients underwent standard cochlear implantation and postoperative temporal bone CT scanning. Scans were analyzed to determine the number of extracochlear electrodes. Standard CI programming had been completed without knowledge of the extracochlear electrodes identified on the CT. These standard CI maps were reviewed to record the number of deactivated basal electrodes. Lastly, each operative report was reviewed to record the extent of reported electrode insertion. 13.4% (n = 35) of CIs were found to have at least one electrode outside of the cochlea on the CT scan. Review of CI mapping indicated that audiologists had deactivated extracochlear electrodes in 60% (21) of these cases. Review of operative reports revealed that surgeons correctly indicated the number of extracochlear electrodes in 6% (2) of these cases. Extracochlear electrodes were correctly identified audiologically in 60% of cases and in surgical reports in 6% of cases; however, it is possible that at least a portion of these cases involved postoperative electrode migration. Given these findings, postoperative CT scans can provide information regarding basal electrode location, which could help improve programming accuracy, associated frequency allocation, and audibility with appropriate deactivation of extracochlear electrodes.

Surgeon Oriented Preoperative Radiologic Evaluation in Cochlear Implantation - Our experience with a Proposed Checklist.

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

Electrocochleography Results in Patients With Bilateral Vestibular Paresis and Sound- or Pressure-Induced Horizontal Nystagmus

To describe the electrocochleography (ECochG) findings in patients with bilateral vestibular paresis and sound- and/or pressure-induced horizontal nystagmus. Retrospective case series. Tertiary care center. Three adult patients with bilateral vestibular paresis and sound- and/or pressure-induced horizontal nystagmus were evaluated from 2012 to 2016. All patients underwent ECochG, vestibular evoked myogenic potential (VEMP) testing, bithermal caloric testing, rotary chair testing, audiometric testing, and temporal bone computed tomography (CT). For ECochG, the summating potential (SP) to action potential (AP) ratio was determined. All patients had normal temporal bone CT, reduced caloric responses bilaterally, decreased gain on rotary chair, and abnormal ECochG. For two subjects, the SP/AP was elevated bilaterally. One subject had unilateral SP/AP elevation. Cervical VEMPs were present in all subjects, but at reduced thresholds in two subjects. SP/AP elevation was found in all three patients with the syndrome of bilateral vestibular paresis and/or sound- or pressure-induced horizontal nystagmus. As the etiology of this syndrome remains unclear, understanding the basis for abnormal ECochG may shed insight into the pathophysiology of this condition.

The Role of Preoperative Computed Tomography of Temporal Bone in Atticotomy as a New Tool for Determining the Approach.

The temporal bone is a complex anatomical structure and so preoperatively computed tomography (CT) of the temporal bone is important for choice of the surgical procedure. In this study, evaluation of the surgical difficulty to conduct transmastoid atticotomy with the coronary cut of CT temporal bone. Additional, attic pathology intraoperative is evaluated. The current research is a retrospective study of 79 patients with chronic suppurative otitis media (safe type) with the preoperative opacity of the attic in CT temporal bone. The researcher correlates difficulty to do transmastoid attictomy with the distance in mm between the roof of external audiatory canal (EAC) and tegmen with ruler directly in the coronary cut of CT temporal bone at the the level of internal auditory canal (IAC). The researcher also compares attic pathology intraoperative with preoperative CT attic opacity. In group of surgically difficulty average distance between the superior wall of EAC and tegmen on preoperative CT at the level of IAC is 2-5mm while distance in easily surgical approach is from 6 to 10mm. 68.4%(54/79) of cases had pathology in attic in the form of granulation tissue in 50 cases and glue in 4 cases. Preoperative CT temporal bone is very important to detect atticotomy approach either transmastoid or transcanal, through measuring the distance in mm between the roof of EAC and tegmen with ruler directly in the coronal cut of CT temporal bone at the level of internal auditory canal. The opacity of the attic in Preoperative CT does not mean that there is a pathology in the attic.

Benefit of Preoperative Temporal Bone CT for Atraumatic Cochlear Implantation.

Evaluate the benefit of preoperative surgical planning using computed tomography (CT) for atraumatic cochlear implantation. The surgical technique has a direct impact on hearing and structure preservation. Much interest has been given to depth of electrode insertion. We focused on electrode diameter depending on exposure of round window membrane (RWM) as calculated on preoperative CT. Measurements were calculated radiologically and anatomically on 10 temporal bones. Results were compared with CT scans of a control population. Thereafter, preoperative CT scan measurements were applied to seven additional temporal bones that underwent cochlear implantation with the insertion of two electrodes of different diameters (14 implantations) to validate radiological analysis. RWM size was 1.5 ± 0.2 mm on CT and 1.2 ± 0.2 mm during dissection; posterosuperior bony overhang of round window niche was 1.1 ± 0.1 mm on CT and 1.3 ± 0.2 mm during dissection. There was no statistically significant difference between radiological and anatomical measurements and between radiological measurements of cadaveric temporal bones and control population (p > 0.05 for both). Also, preoperative surgical planning was reliable in the seven temporal bones implanted with two electrode types (accuracy 93%, sensitivity 85.7%, specificity 100%) yielding no damage to intracochlear structures. Difficulties to access RWM could be predicted on preoperative CT of temporal bones and control population, which correlated well with anatomical dissections and surgical findings during cochlear implantation. According to CT planning, electrode insertion through RWM was feasible in most patients, with or without drilling posterosuperior bony overhang of round window niche. Promontory cochleostomy could be recommended when electrode apical diameter exceeded maximal RWM exposure. There was no case of intracochlear trauma on microdissections.

Efficacy of Tympanoplasty Without Mastoidectomy for Treating Chronic Otitis Media in Patients With Mastoid Cavity Opacification in Temporal Bone Computed Tomography Findings.

Objectives Combined mastoidectomy is generally preferred to tympanoplasty alone when treating patients with chronic otitis media (COM), particularly when temporal bone computed tomography (TBCT) shows that the mastoid cavity contains opacification of soft tissue density. However, in cases with Eustachian tube dysfunction, a mastoid cavity volume may be a burden to its function. We hypothesized that tympanoplasty alone might be better than tympanoplasty combined with mastoidectomy because soft tissue in the mastoid cavity is a sequel to a protective physiological response. Thus, we explored the efficacy of tympanoplasty without mastoidectomy in COM patients exhibiting mastoid air cell opacification on TBCT.Methods Between 2010 and 2014, a total of 33 patients, diagnosed with COM and with evidence of mastoid cavity opacification on TBCT, underwent tympanoplasty without mastoidectomy. All ears had been dry for ≥3 months before surgery. All procedures were performed by the same surgeon. We retrospectively analyzed the preoperative otoscopic findings, pre- and postoperative pure tone averages (PTAs; the mean of the values at 0.5, 1, 2, and 4 kHz), surgical procedures, and complications or recurrence.Results Of the 33 patients, 28 (84.8%) exhibited hearing improvement after surgery. The mean pre- and postoperative PTAs were 46.9±21.2 dB and 29.4±17.0 dB, respectively (P<0.001). The air-bone gap decreased from 25.7±10.7 dB to 10.3±8.7 dB (P<0.001). Thirty-two patients (97.0%) did not develop any COM recurrence or cholesteatoma; one patient developed attic retraction of the tympanic membrane. Other minor complications were transient otorrhea caused by myringitis (two cases) and a pinpoint perforation (one case).Conclusion Tympanoplasty alone, i.e., without mastoidectomy, may adequately control COM, if it shows dry-up status for at least 3 months even though mastoid cavity opacification is detected in TBCT.

Risk of Posterior Semicircular Canal Trauma when using a Retrosigmoid approach for Acoustic Neuroma Surgery and role of Endoscopy: An Imaging Study

Benzalkonium chloride (BAC) is a bactericidal preservative excipient commonly found in steroid nasal sprays used to treat allergic rhinitis and nasal polyposis. In rare cases, BAC can be responsible for type I and type IV hypersensitivity reactions that can manifest as rhinorrhea, which a clinician might misinterpret as a lack of response to nasal spray therapy rather than a complication of it. We report 3 cases of type IV hypersensitivity reactions in patients who were being treated with mometasone nasal spray. We describe the epidemiology, clinical features, diagnosis, and treatment of these reactions.

Risk of posterior semicircular canal trauma when using a retrosigmoid approach for acoustic neuroma surgery and role of endoscopy: An imaging study.

The rate of hearing preservation after vestibular schwannoma surgery is variable and is not as high as expected, possibly due to injuries to the posterior semicircular canal while exposing the tumor. The aim of this study was to estimate the risk of posterior semicircular canal injuries using temporal bone computed tomography (CT) scan findings. Temporal bone CT scans of 30 patients selected between 2013 and 2015 were studied. The median age of the patients was 40 years. Two planes were studied: (1) the axial plane that shows the common crus of the posterior semicircular canal and (2) the coronal plane that shows the two crura of the posterior semicircular canal. Five lines were drawn and four angles and three distances were measured. In this study, we divided the patients into three groups consisting of 10 patients each: (1) patients with no evidence of inflammatory or neoplastic disease, (2) those with chronic ear disease, and (3) those with vestibular schwannomas. The portion of the internal auditory canal that was exposed by drilling while preserving the posterior semicircular canal was 53 to 64% and 61 ± 9% in whole temporal bones in the three groups. The mean angle of vision with an endoscope was less than 105° in 56% of cases, which means even with a 30° endoscope, the fundus could not be visualized. Therefore, according to our data, it seemed impossible to expose the whole length of the internal auditory canal from the porus to the fundus without causing injury to the posterior semicircular canal. However, the use of endoscopes may help to prevent injury.

A novel method to measure the external auditory canal: Normative data and practical implications

PurposeTo accurately measure external auditory canal (EAC) dimensions by high resolution computed tomography (CT), and compare results with a traditional method of EAC measurement. MethodsUsing an advanced multidimensional open source digital imaging and communications in medicine (DICOM) analysis program (OsiriX, Pixmeo, Geneva, Switzerland) 91 adult EACs were analyzed on a previously obtained temporal bone CT scan. Tympanometric data were also recorded for each ear. The methods were compared using a linear mixed effect model. ResultsEAC volume was compared between tympanometrically calculated volumes and CT measured volumes. It was found that CT measured volumes are, on average, smaller (1.12cm3, SE=0.04) than tympanometry volumes (1.27cm3, SE=0.04cm3). There was a significant difference in CT measured volume between genders (p=0.0125), with males having larger measured volumes (1.23cm3, SD=0.28cm3) than females (1.06cm3, SD=0.20cm3). There was a significant difference in average circumference between ear laterality (p=0.0071), with the right ear having a slightly larger average circumference (2.49cm, SD=0.23cm) than the left ear (2.44cm, SD=0.50cm).There was also a significant difference in minimum circumference between age groups (p=0.0448), with patients younger than 60years having larger minimum circumferences (1.89cm, SD=0.21cm) than older patients (1.78cm, SD=0.25cm). ConclusionsThis study demonstrates that CT analysis can provide more information about EAC dimensions than traditional techniques. Moreover, slight but statistically significant differences are associated with age, gender and laterality. Accurate estimation of EAC dimensions is important for the development of hearing aids and personal protective equipment and can also be helpful for surgical planning, specifically otoendoscopy. Future research will focus on simplifying computation, developing cross-cultural cohort comparisons, and application to otoendoscopic procedures.

Clinical Importance of Temporal Bone Features for the Efficacy of Contrast-Enhanced Sonothrombolysis: a Retrospective Analysis of the NOR-SASS Trial.

Contrast-enhanced sonothrombolysis (CEST) seems to be a safe and promising treatment in acute ischemic stroke. It remains unknown if temporal bone features may influence the efficacy of CEST. We investigated the association between different temporal bone features on admission computed tomography (CT) scan and the outcome in acute ischemic stroke patients included in the randomized Norwegian Sonothrombolysis in Acute Stroke Study (NOR-SASS). Patients diagnosed as stroke mimics and those with infratentorial stroke or with incorrect insonation were excluded. We retrospectively assessed temporal bone heterogeneity (presence of diploë), diploë ratio, thickness, and density on admission CT scans. National institute of Health Stroke Scale (NIHSS) at 24h and modified Rankin Scale (mRS) at 3months were correlated with CT findings both in CEST and sham CEST patients. A total of 99 patients were included of which 52 were assigned to CEST and 47 to sham CEST. Approximately 20% patients had a heterogeneous temporal bone in both the CEST and sham CEST group. All temporal bone CT features studied were associated with female sex. In the CEST group, temporal bone heterogeneity (p=0.006) and higher temporal bone diploë ratio (p=0.002) were associated with higher NIHSS at 24h. There was no association between temporal bone features and mRS at 3months. Approximately 20% of acute ischemic stroke patients have heterogeneous temporal bone and may be resistant to standard 2-MHz transcranial Doppler ultrasound treatment. Sonothrombolysis resistance may easily be predicted by admission CT for better selection.

Can Preoperative CT Scans Be Used to Predict Facial Nerve Stimulation Following CI?

1) To determine the ability of preoperative computed tomography (CT) to predict facial nerve stimulation (FNS) after cochlear implantation (CI). 2) To recognize the limitations of CT in predicting FNS. Patient control study. Tertiary care academic medical center. Adult patients with CI from 2003 to 2015. Patients with severe FNS (n = 4) were compared with randomly selected CI patients (n = 28). Three blinded reviewers evaluated preoperative temporal bone CT scans to measure the distance from the labyrinthine segment of the facial nerve to the basal turn of the cochlea and attempted to predict whether or not the subject had FNS after CI. In total, 32 CT scans were evaluated representing 49 ears that underwent CI.The distances (mm) measured from the labyrinthine segment of the facial nerve to the basal turn of the cochlea in both the axial (0.3 ± 0.3 versus 0.6 ± 0.3) and coronal (0.4 ± 0.2 versus 0.6 ± 0.2) orientation were significantly different between the two groups (p = 0.0001 and p = 0.0034) respectively. The intraclass correlation coefficient demonstrated good (K > 0.7) reviewer correlation in both the reviewers' measurements and predictions. The sensitivity, specificity, positive predictive value, and negative predictive value for preoperative CT scans to predict FNS were 38.5, 85.1, 19.2, and 93.8% respectively. The reviewers were 23% accurate in predicting FNS. Based on a blinded retrospective patient-control study, CT scan measurements show a significantly reduced distance between the labyrinthine facial nerve and the basal turn of the cochlea in patients with FNS. However, it is difficult to predict who will have FNS based on these measurements.

Aksiyel düzlemde elde edilen kesitlerin rekonstrüksiyonuyla hangi temporal kemik anatomik ve patolojik oluşumları en iyi görüntülenebilir?

Objective: In this study, we aimed to identify the position in which temporal bone anatomical structures and pathologies could be best visualized by applying reconstruction to cross-sections obtained on an axial plane in temporal bone computed tomography (CT) scans. Methods: Sixty patients were examined with temporal bone CT between July 2008 and March 2009. We obtained multiplanar reformatted images by applying retro-reconstruction on various planes from the axial plane sections. Results: We determined that the reconstructed images increased the anatomical and pathological details and significantly contributed to evaluating the relationship between anatomical structures and their pathologies with other normal components. Conclusion: Obtaining multiplanar reformatted images by retro-reconstruction decreased the need for visualization of coronal sections used in standard temporal bone CT exams since the anatomical details were diversified using the new planes. In addition, the dose of radiation received by the patients and the duration of the examination could be reduced by eliminating routine coronal plane sections and obtaining new images using retro-reconstruction.

The role of preoperative computerized tomography in a safe posterior tympanotomy for cochlear implant surgery

A posterior tympanotomy is a technique performed to access round window area to insert cochlear implant electrode into round window membrane or through cochleostomy. In this study, we aimed to classify and evaluate the anatomical relationships between the facial nerve (FN) (vertical segment), chorda tympani nerve, and facial recess (FR) pneumatization in an axial temporal bone computerized tomography (CT) to be safe when performing a posterior tympanotomy. We performed a retrospective analytic study of temporal bone CT scans. A cohort of 51 patients who underwent cochlear implantation with classical mastoidectomy with posterior tympanotomy were included. All patients had preoperative diagnostic CT of the temporal bone from January 2014 to November 2015. Anatomical correlations were classified according to several parameters including protrusion of the FN into the antrum, FR pneumatization, and status of the facial canal. Anatomical relationships between the vertical segment and posterior tympanotomy were classified into three types: type 1, the FN has no protrusion with a regular facial canal with pneumatized FR; type 2, the FN has protrusion into the antrum with a regular facial canal and/or poorly pneumatized FR; and type 3, the FN has sclerotic mastoid with no FR pneumatization. These results enable preoperative evaluation of the FN’s status and difficulty while performing posterior tympanotomy, providing basic knowledge to prevent injury of the FN while performing a posterior tympanotomy.

Imaging of the temporal bone in children using low-dose 320-row area detector computed tomography.

The aim of this study was to compare the image quality obtained using low-dose and standard-dose 320-row temporal bone computed tomography (CT) in paediatric patients. Thirteen low-dose CT (120kV/50mAs) and nine standard-dose CT (120kV/100mAs) images from children up to 5years of age were compared for their image quality. The noise and signal-to-noise ratio for bone, fat and air were measured. Two observers assessed the overall image quality and ability to visualize 14 small anatomic structures using a 5-point scale, with a score of 3-5 indicating imaging of diagnostic quality. Noise was significantly higher and the signal-to-noise ratio was significantly lower with low-dose CT. Although the overall image quality and visibility of several structures on low-dose CT were significantly reduced when compared with standard-dose CT, all the image quality scores were 3 or >3. The dose-length products for low-dose CT and standard-dose CT were 59.6mGy·cm and 119.3mGy·cm, respectively. Low-dose CT of the temporal bone using 320-row CT provides images of diagnostic quality for assessment of middle and inner ear anatomy, similar to that provided by the standard-dose protocol, in spite of increased image noise.

Additive value of "otosclerosis-weighted" images for the CT diagnosis of fenestral otosclerosis.

Background Otosclerotic foci are usually seen as minute low-density lesions and this may be attributed to relatively low sensitivity on visual assessment using computed tomography (CT). Otosclerotic foci can be detected by using the accurate region of interest (ROI) setting, while small ROI settings by less-experienced radiologists may result in false negative findings. Purpose To evaluate the diagnostic ability of our proposed method ("otosclerosis-weighted" imaging [OWI]), which is based on reversing the density, compared with conventional CT (CCT) imaging alone. Material and Methods Temporal bone CTs of consecutive patients with otosclerosis were analyzed. Gender- and age-matched control participants were also included. All CT images were obtained using a 64-detector row scanner. OWI was obtained by extracting the temporal bone region using the threshold technique and reversing the density (black to white). Four independent radiologists took part in two reading sessions. In the first session, the observers read only CCT imaging. In the second session, they read OWI along with the CCT imaging. Sensitivity was assessed for the four readers. Results Thirty temporal bones of 25 patients with otosclerosis (3 men, 22 women; mean age, 53.9 ± 9.0 years) and 30 temporal bones of 30 control participants (4 men, 26 women; mean age, 44.0 ± 16.2 years) were included. For all observers, reading with a combination of the two methods was associated with a higher sensitivity (63.3-80.0%) than with conventional CT images alone (30.0-60.0%; P < 0.05, each). Conclusion Application of our proposed method based on threshold value may help detect foci of fenestral otosclerosis.

Cochleariform Process Abutment on TBCT in Early Congenital Cholesteatoma.

To study the influence of the cochleariform process abutment (CPA) of early congenital cholesteatomas (CC) (ECCs) on surgical outcomes. Retrospective case review. University hospital otology referral clinic. Two hundred consecutive pediatric ECC patients. The patients were classified into three groups based on the temporal bone computed tomography (TBCT) findings of ECC: A) the absence of CPA, B) the presence of CPA, and C) the presence of CPA and extension posterior to the malleus handle. Residual CC according to each of the TBCT and surgical stages during 34.9 ± 20.1 months of follow-up. Group A was significantly associated with effortless delivery without matrix tearing (77%) even with simple myringotomy. Only 17% of group B experienced this outcome, and troublesome matrix tearing occurred in significantly more patients (p < 0.0001). Residual CCs were present in 17.5% of group B if matrix tears occurred, which was comparable to group C (22.0%) and significantly greater than group A (4.4%, p = 0.03). Normal hearing was preserved in 97.5% of the ECC patients both when the ECCs did not recur and when they recurred without CPA. However, residual ECCs with positive CPAs in five children (2.5%) required ossicle removal, and subsequent hearing loss. CPA is directly related to intraoperative matrix tear or increased recidivism, that CPA should be the landmark to distinguish stage II ECC from stage I. Surgeons should evaluate CPA on preoperative TBCTs of ECC patients, and restrict myringotomy approach to CPA negative ECC.

When to operate facial nerve schwannomas?

Facial nerve schwannomas are rare, benign slow-growing tumors arising from the Schwann cell sheath of the facial nerve. A 60-year-old female presented with a mass in the left parotid region for 6 months. It was associated with Grade 6 left lower motor neuron facial palsy. Malignancy of the parotid gland associated with facial nerve involvement was suspected. However, high-resolution computed tomography temporal bone and magnetic resonance imaging done showed a soft-tissue density along the vertical portion of the facial nerve and into the parotid gland. The lesion was eroding the skull base and was found to be in direct contact with the jugular bulb. She underwent excision of the tumor by a modified Blair incision along with a cortical mastoidectomy. Tumor abutting the jugular bulb was removed through transmastoid approach. Facial nerve was transected during tumor excision. Postoperatively, gold implant was inserted. Facial schwannomas can arise from any segment of the nerve, from the cerebellopontine angle to the extratemporal peripheral portion. About 650 cases have been reported in the world literature. The best timing for surgery depends on facial and hearing function, size, and intracranial mass effect.