Changes of Temporal Processing and Hearing in Noise after Use of a Monoaural Hearing Aid in Patients with Sensorineural Hearing Loss: A Preliminary Study.

BACKGROUND AND OBJECTIVES: The relationship between hearing aid (HA) use and improvement in cognitive function is not fully known. This study aimed to determine whether HAs could recover temporal resolution or hearing in noise functions. Materials and. METHODS: We designed a prospective study with two groups: HA users and controls. Patients older than 45 years, with a pure tone average threshold of worse than 40 dB and a speech discrimination score better than 60% in both ears were eligible. Central auditory processing tests and hearing in noise tests (HINTs) were evaluated at the beginning of the study and 1, 3, 6, and 12 months after the use of a monaural HA in the HA group compared to the control group. The changes in the evaluation parameters were statistically analyzed using the linear mixed model. RESULTS: A total of 26 participants (13 in the HA and 13 in the control group) were included in this study. The frequency (p<0.01) and duration test (p=0.02) scores showed significant improvements in the HA group after 1 year, while the HINT scores showed no significant change. CONCLUSIONS: After using an HA for one year, patients performed better on temporal resolution tests. No improvement was documented with regard to hearing in noise.

Does Rapid Eye Movement Sleep Aggravate Obstructive Sleep Apnea?

OBJECTIVES: To investigate the apnea-hypopnea index (AHI) according to the sleep stage in more detail after control of posture. METHODS: Patients who underwent nocturnal polysomnography between December 2007 and July 2018 were retrospectively evaluated. Inclusion criteria were as follows: age >18 years, sleep efficacy >80%, and patients who underwent polysomnography only in the supine position (100% of the time). Patients were classified into different groups according to the methods the first, rapid eye movement (REM)-dominant group (AHIREM/AHINREM >2), non-rapid eye movement (NREM)-dominant group (AHINREM/AHIREM >2), and non-dominant group; and the second, light sleep group (AHIN1N2>AHISWS) and slow wave sleep (SWS) group (AHISWS>AHIN1N2). RESULTS: A total of 234 patients (mean age, 47.4±13.9 years) were included in the study. There were 108 patients (46.2%) in the REM-dominant group, 88 (37.6%) in the non-dominant group, and 38 (16.2%) in the NREM-dominant group. The AHI was significantly higher in the NREM-dominant group than in the REM-dominant group (32.9±22.9 events/hr vs. 18.3±9.5 events/hr, respectively). There were improvements in the AHI from stage 1 to SWS in NREM sleep with the highest level in REM sleep. A higher AHISWS than AHIN1N2 was found in 16 of 234 patients (6.8%); however, there were no significant predictors of these unexpected results except AHI. CONCLUSION: Our results demonstrated the highest AHI during REM sleep stage in total participants after control of posture. However, there were 16.2% of patients showed NREM-dominant pattern (AHINREM/AHIREM >2) and 6.8% of patients showed higher AHISWS than AHIN1N2. Therefore, each group might have a different pathophysiology of obstructive sleep apnea (OSA), and we need to consider this point when we treat the patients with OSA.

Cochlear Implantation in Postlingually Deaf Adults is Time-sensitive Towards Positive Outcome: Prediction using Advanced Machine Learning Techniques.

Given our aging society and the prevalence of age-related hearing loss that often develops during adulthood, hearing loss is a common public health issue affecting almost all older adults. Moderate-to-moderately severe hearing loss can usually be corrected with hearing aids; however, severe-to-profound hearing loss often requires a cochlear implant (CI). However, post-operative CI results vary, and the performance of the previous prediction models is limited, indicating that a new approach is needed. For postlingually deaf adults (n de120) who received CI with full insertion, we predicted CI outcomes using a Random-Forest Regression (RFR) model and investigated the effect of preoperative factors on CI outcomes. Postoperative word recognition scores (WRS) served as the dependent variable to predict. Predictors included duration of deafness (DoD), age at CI operation (ageCI), duration of hearing-aid use (DoHA), preoperative hearing threshold and sentence recognition score. Prediction accuracy was evaluated using mean absolute error (MAE) and Pearson's correlation coefficient r between the true WRS and predicted WRS. The fitting using a linear model resulted in prediction of WRS with r = 0.7 and MAE = 15.6 ± 9. RFR outperformed the linear model (r = 0.96, MAE = 6.1 ± 4.7, p < 0.00001). Cross-hospital data validation showed reliable performance using RFR (r = 0.91, MAE = 9.6 ± 5.2). The contribution of DoD to prediction was the highest (MAE increase when omitted: 14.8), followed by ageCI (8.9) and DoHA (7.5). After CI, patients with DoD < 10 years presented better WRSs and smaller variations (p < 0.01) than those with longer DoD. Better WRS was also explained by younger age at CI and longer-term DoHA. Machine learning demonstrated a robust prediction performance for CI outcomes in postlingually deaf adults across different institutes, providing a reference value for counseling patients considering CI. Health care providers should be aware that the patients with severe-to-profound hearing loss who cannot have benefit from hearing aids need to proceed with CI as soon as possible and should continue using hearing aids until after CI operation.

Changes of video head impulse test results in lateral semicircular canal plane by different peak head velocities in patients with vestibular neuritis.

BACKGROUND: The peak head velocity influences on the video head impulse test (vHIT) results, but it has been not known how much the difference is. AIMS: To evaluate the clinical evidence for the superiority of high-velocity compared to low-velocity vHIT. MATERIAL AND METHODS: vHIT was performed in 30 patients with vestibular neuritis using two peak head velocities (mean 80 vs. 240°/s). vHIT gains and parameters of corrective saccades (CSs) were compared. A vHIT gain of ≤0.8 or a peak CS velocity of ≥100°/s was considered pathologic. RESULTS: The vHIT gains were significantly lower (mean 0.5 vs. 0.6), and GA was larger (35 vs. 25%) at high-velocity vHIT, compared to low-velocity vHIT. CSs were significantly more frequent (100 vs. 80%) and peak CS velocities were larger (252 vs. 112°/s) at high-velocity vHIT. The abnormal rates based on vHIT gains were higher (90% vs. 73%) and CSs occurred more frequently (100% vs. 80%) at high-velocity vHIT. The abnormal rates based on the peak CS velocity were significantly higher at high-velocity vHIT (100% vs. 57%). CONCLUSION: High-velocity vHIT is superior to low-velocity vHIT with a difference of 17-20% based on pathologic vHIT gains and presence of CSs.

Prognostic roles of preoperative CT findings and air-bone gaps in type 1 tympanoplasty.

BACKGROUND: Although CT has been used widely, the role of preoperative CT findings including other factors in tympanoplasty has not been elucidated comprehensively. AIMS/OBJECTIVES: To evaluate relationship of CT findings with other factors and audiological results in type 1 tympanoplasty. MATERIAL AND METHODS: A cohort of consecutive 175 patients with type 1 tympanoplasty was enrolled. Addition of mastoidectomy was based on the presence of soft tissue in antrum on CT. Postoperative air-bone gap (ABG) and reperforation rate were analyzed. RESULTS: Positive soft tissue in antrum on CT was found in 52 (29.7%) patients and showed larger preoperative ABG than the negative group. Successful ABG closure (≤20 dB) was obtained in 97% when preoperative ABG ≤20 dB, but it decreased as the preoperative ABG increased (83% with preoperative ABG of 21-30 dB, and 0% with preoperative ABG >30 dB). Postoperative reperforation rate was positively related to the preoperative ABG, but not the presence of soft tissue in the antrum, the size, or locations of preoperative perforations. CONCLUSIONS AND SIGNIFICANCE: Our findings showed that temporal bone CT was helpful in determining addition of mastoidectomy and the presence of soft tissue in the antrum was associated with large ABG.

Diagnostic Value of Gains and Corrective Saccades in Video Head Impulse Test in Vestibular Neuritis.

Objectives We investigated changes in video head impulse test (vHIT) gains and corrective saccades (CSs) at the acute and follow-up stages of vestibular neuritis to assess the diagnostic value of vHIT. Study Design Case series with chart review. Setting Tertiary medical center. Subjects and Methods Sixty-three patients with vestibular neuritis who underwent vHIT at an initial presentation and an approximately 1-month follow-up were included. vHIT gains, gain asymmetry (GA), peak velocities of CS, and interaural difference of CS (CSD) were analyzed. Results Mean vHIT gains increased significantly from the acute stage to the follow-up exam. The mean GA, peak velocities of CS, and CSD had decreased significantly at the follow-up. The incidence of CSs was also significantly decreased at the follow-up. The abnormal rate (87%) considering both gain and CS value was significantly higher than that (62%) considering vHIT gain only at the follow-up, although the abnormal rates did not differ at the acute stage (97% vs 87%). Conclusion The abnormal rates based on both vHIT gains and CS measurements are similar at the acute stage of VN but are considerably higher at the follow-up stage compared with the abnormal rates based on vHIT gains alone. It is thus advisable to check both CS and vHIT gain while performing vHIT to detect vestibular hypofunction.

Comparison of Video Head Impulse Test (vHIT) Gains Between Two Commercially Available Devices and by Different Gain Analytical Methods.

OBJECTIVES: To evaluate whether video head impulse test (vHIT) gains are dependent on the measuring device and method of analysis. STUDY DESIGN: Prospective study. METHODS: vHIT was performed in 25 healthy subjects using two devices simultaneously. vHIT gains were compared between these instruments and using five different methods of comparing position and velocity gains during head movement intervals. RESULTS: The two devices produced different vHIT gain results with the same method of analysis. There were also significant differences in the vHIT gains measured using different analytical methods. The gain analytic method that compares the areas under the velocity curve (AUC) of the head and eye movements during head movements showed lower vHIT gains than a method that compared the peak velocities of the head and eye movements. The former method produced the vHIT gain with the smallest standard deviation among the five procedures tested in this study. CONCLUSION: vHIT gains differ in normal subjects depending on the device and method of analysis used, suggesting that it is advisable for each device to have its own normal values. Gain calculations that compare the AUC of the head and eye movements during the head movements show the smallest variance.

Bone mineral density and serum 25-hydroxyvitamin D in patients with idiopathic benign paroxysmal positional vertigo.

The aim of this study was to evaluate the relationship between bone mineral density (BMD) and 25-hydroxyvitamin D with the occurrence and recurrence of BPPV. The records of 130 idiopathic BPPV patients (55±12 years old, 30 men and 100 women) and 130 age- and sex-matched controls who underwent bone mineral densitometry between April 2012 and September 2015 were reviewed retrospectively. We compared the BMD and serum 25-hydroxyvitamin D between the patients and controls, and also compared the BMD between recurrent and non-recurrent BPPV groups. Among the female subjects, the BPPV group showed a significantly decreased BMD compared to the controls (p < 0.05). The men in the control group had significantly higher 25-hydroxyvitamin D levels than the men with BPPV (p < 0.05). Sixty-three patients (48%) reported recurrent attacks of BPPV. The women with recurrent BPPV were significantly older and showed a significantly lower BMD than non-recurrent women (p < 0.001). However, multiple regression analysis revealed that age alone was significantly associated with the recurrence of BPPV in women. BMD in women and serum 25-hydroxyvitamin D levels in men are associated with the occurrence of BPPV. Only age is an independent predictor of recurrence, though a low BMD and age correlate with the recurrence of BPPV.

What Is the Sensitive Period to Initiate Auditory Stimulation for the Second Ear in Sequential Cochlear Implantation?

OBJECTIVES: Bilateral cochlear implants (CI) are the standard treatment for bilaterally deaf children, but it is unclear how much the second CI can be delayed in sequential bilateral CI. We investigated the performances of sequential CI to answer this question. STUDY DESIGN: Retrospective case series review. SETTING: Tertiary referral center. METHODS: We studied a cohort of congenitally deaf children (n = 73) who underwent sequential CI without any inner ear anomaly or combined disabilities. Hearing threshold levels and speech perception were evaluated by aided pure tone audiometry and Asan-Samsung Korean word recognition test. The scores were analyzed by the ages at surgery and compared among the different age groups. RESULTS: When the second CI was performed before 3.5 years (the optimal period for the first CI), the second CI scores (96.9%) were comparable to the first CI scores. Although the first CI scores were more than or equal to 80% when the first CI was implanted before the age of 7 years, the second CI scores were more than or equal to 80% when the second CI was implanted before the age of 12 to 13 years. The hearing threshold levels were not different regardless of the ages and between the first and second CIs. CONCLUSION: Our cohort demonstrated that the second CI showed comparable results to the first CI when implanted before 3.5 years, suggesting that optimal periods for the first CI and the second CI are same. However, the sensitive period (12-13 yr) for the second CI with good scores (≥80%) was much longer than that (7 yr) of the first CI, suggesting that the first CI prolongs the sensitive period for the second CI. The second CI should be implanted early, but considered even at a later age.

A cadaver study of mastoidectomy using an image-guided human-robot collaborative control system.

Objective: Surgical precision would be better achieved with the development of an anatomical monitoring and controlling robot system than by traditional surgery techniques alone. We evaluated the feasibility of robot-assisted mastoidectomy in terms of duration, precision, and safety. Study Design: Human cadaveric study. Materials and Methods: We developed a multi-degree-of-freedom robot system for a surgical drill with a balancing arm. The drill system is manipulated by the surgeon, the motion of the drill burr is monitored by the image-guided system, and the brake is controlled by the robotic system. The system also includes an alarm as well as the brake to help avoid unexpected damage to vital structures. Experimental mastoidectomy was performed in 11 temporal bones of six cadavers. Parameters including duration and safety were assessed, as well as intraoperative damage, which was judged via pre- and post-operative computed tomography. Results: The duration of mastoidectomy in our study was comparable with that required for chronic otitis media patients. Although minor damage, such as dura exposure without tearing, was noted, no critical damage to the facial nerve or other important structures was observed. When the brake system was set to 1 mm from the facial nerve, the postoperative average bone thicknesses of the facial nerve was 1.39, 1.41, 1.22, 1.41, and 1.55 mm in the lateral, posterior pyramidal and anterior, lateral, and posterior mastoid portions, respectively. Conclusion: Mastoidectomy can be successfully performed using our robot-assisted system while maintaining a pre-set limit of 1 mm in most cases. This system may thus be useful for more inexperienced surgeons. Level of Evidence: NA.

Prognostic Factors for Recovery from Sudden Sensorineural Hearing Loss: A Retrospective Study.

BACKGROUND AND OBJECTIVES: This study aimed to investigate prognostic factors in patients with idiopathic sudden sensorineural hearing loss (ISSNHL). SUBJECTS AND METHODS: From January 2007 to December 2011, a retrospective chart review identified 494 consecutive patients with ISSNHL. Demographic, audiometric, and clinical data were analyzed using a logistic regression test. RESULTS: Hearing recovery from ISSNHL was significantly associated with factors such as age, duration from onset of symptoms to commencement of treatment, severity of the initial pure tone threshold, and the treatment method. Intratympanic (IT) steroid administration alone showed a comparable efficiency to oral steroid administration with or without IT steroid injection. In patients who received IT steroid injection, the duration from onset to treatment, severity of initial hearing loss, and sequential IT steroid injection following systemic steroid administration were statistically associated with hearing improvement. CONCLUSIONS: Age, severity of initial pure tone threshold, duration from onset to treatment, initial speech discrimination, and initial pure tone threshold are statistically significant prognostic factors related to hearing improvement in ISSNHL. IT steroid injection as an initial single treatment is comparable to systemic oral steroid administration.

Efficacy of steroid therapy based on symptomatic and functional improvement in patients with vestibular neuritis: a prospective randomized controlled trial.

The aim of this study was to examine the efficacy of methylprednisolone in vestibular neuritis (VN) by objective and subjective measures. This prospective controlled randomized study was conducted at one tertiary hospital. Twenty-nine VN patients were randomized to either the steroid (n = 15) or the control (n = 14) group. The steroid group received methylprednisolone for 2 weeks, whereas control patients did not; both groups underwent regular vestibular exercises and were prescribed a Ginkgo biloba. Vestibular function tests including caloric test, video head impulse test (vHIT), and sensory organization test (SOT) were performed, and dizziness handicap index (DHI) was determined at enrollment; all tests were repeated at 1 and 6 months after enrollment. Both groups showed statistically significant improvements in caloric weakness and vHIT gain at 1- and 6-month follow-up evaluations compared to the initial examination; however, differences were not significant. The rates of normalization of canal paresis at 1 and 6 months were 50 and 64% in the control group and 33 and 60% in the steroid group, respectively, with no differences between the two groups. The rates of vHIT normalization at 1 and 6 months after treatment were 57 and 78% in the control group and 53 and 87% in the steroid group, respectively, with no differences between the two groups. Finally, there were no significant differences in the improvement of composite scores of SOT and the DHI scores between the two groups. In this prospective RCT, methylprednisolone had no additional benefit in patients with VN who underwent vestibular exercises and received a Ginkgo biloba. TRIAL REGISTRATION: Clinicaltrials.gov Identifier, NCT02098330; Trial title, The Efficacy of Steroid Therapy in Vestibular Neuritis.

Development of a murine model of traumatic benign paroxysmal positional vertigo: a preliminary study.

CONCLUSION: The results showed a gradual detachment of otoconia in the utricle after a single event of head vibration, possibly explaining the frequent recurrence of BPPV attacks and persistent dizziness after trauma. OBJECTIVES: This study developed a murine model of traumatic BPPV and observed the changes in otoconia detachment over time. METHODS: Six-week-old CBA mice were used in this study. Otoconia detachment was induced by vibrating the head for 2 min. Utricles of mice were harvested from different groups: before the head vibration and 1 day, 1 week, 1 month, and 3 months after vibration application. Using scanning electron microscopy and ImageJ software, the percentage of the intact area of otoconia in the utricle was calculated. Hearing thresholds were compared among the groups. RESULTS: The mean (± SD) percentages of the intact area of otoconia in the utricle were 98.1% ± 1.7% before the vibration and 93.6% ± 1.7%, 88.9% ± 5.3%, 78.2% ± 20.9%, and 38.9% ± 24.1% at 1 day, 1 week, 1 month, and 3 months after the vibration, respectively. The percentage decreased significantly over time after the vibration (p < .001). The hearing thresholds were not different among the groups.

Surgical outcomes of middle fossa approach in intracanalicular vestibular schwannoma.

CONCLUSION: Middle fossa approach (MFA) shows a hearing preservation rate of 86% and facial nerve function was preserved with HB grade I or II in 93%. MFA is a good treatment option for intra-canalicular vestibular schwannomas when surgical excision is needed. BACKGROUND: Surgical outcomes of vestibular schwannoma have progressively improved with the advancement of microsurgical instruments. MFA is known to have better chances to preserve hearing, while it has limited access to the posterior fossa, limitation of tumor size, and higher risk of post-operative facial nerve weakness. OBJECTIVES: To investigate surgical outcomes and clinical efficiency of MFA in vestibular schwannoma. METHODS: A retrospective study was done in 14 patients who underwent MFA for vestibular schwannoma in Asan Medical Center. RESULTS: The median age at diagnosis was 46.3 years. At initial presentation, 57% of the patients had vertigo, 43% hearing disturbance, and 64% tinnitus. The mean tumor size was 9.7 mm. The tumors were completely resected in 86% of the patients. Hearing was post-operatively preserved in 12 patients and two patients lost their hearing following surgery. Facial nerve function post-operatively remained unchanged in 12 patients (86%).

A Case of Squamous Cell Carcinoma in the External Auditory Canal Previously Treated for Verrucous Carcinoma.

Carcinoma in the external auditory canal (EAC) is a rare malignancy with an annual incidence of one per one million people, accounting for less than 0.2% of all head and neck cancers. The most common histopathological type of EAC cancer is squamous cell carcinoma. Verrucous carcinoma is a well-differentiated, low-grade variant of squamous cell carcinoma. It is a locally destructive, invasive, and slow growing tumor that rarely metastasizes. Verrucous carcinoma occurs predominantly in the oral cavity and larynx, and its occurrence in the EAC is extremely rare. In this report, we present a histologically confirmed case of verrucous carcinoma in the EAC and temporal bone, which for several years had been classified as epithelial hyperplasia. Two-and-a-half years after diagnosis of verrucous carcinoma, a recurrent mass was found and the lesion was then confirmed to be squamous cell carcinoma.

Vestibular Function Tests for Vestibular Migraine: Clinical Implication of Video Head Impulse and Caloric Tests.

Vestibular migraine (VM) is one of the most common causes of episodic vertigo. We reviewed the results of multiple vestibular function tests in a cohort of VM patients who were diagnosed with VM according to the diagnostic criteria of the Barany Society and the International Headache Society and assessed the efficacy of each for predicting the prognosis in VM patients. A retrospective chart analysis was performed on 81 VM patients at a tertiary care center from June 2014 to July 2015. Patients were assessed by the video head impulse test (vHIT), caloric test, vestibular-evoked myogenic potentials (VEMPs), and sensory organization test (SOT) at the initial visit and then evaluated for symptomatic improvement after 6 months. Complete response (CR) was defined as no need for continued medication, partial response (PR) as improved symptoms but need for continued medication, and no response (NR) as no symptomatic improvement and requiring increased dosage or change in medications. At the initial evaluation, 9 of 81 patients (11%) exhibited abnormal vHIT results, 14 of 73 (19%) exhibited abnormal caloric test results, 25 of 65 (38%) exhibited abnormal SOT results, 8 of 75 (11%) exhibited abnormal cervical VEMP results, and 20 of 75 (27%) exhibited abnormal ocular VEMP results. Six months later, 63 of 81 patients (78%) no longer required medication (CR), while 18 (22%) still required medication, including 7 PR and 11 NR patients. Abnormal vHIT gain and abnormal caloric results were significantly related to the necessity for continued medication at 6-month follow-up (OR = 5.67 and 4.36, respectively). Abnormal vHIT and caloric test results revealed semicircular canal dysfunction in VM patients and predicted prolonged preventive medication requirement. These results suggest that peripheral vestibular abnormalities are closely related to the development of vertigo in VM patients.

Amplification of transcutaneous and percutaneous bone-conduction devices with a test-band in an induced model of conductive hearing loss.

OBJECTIVE: Transcutaneous devices have a disadvantage, the dampening effect by soft tissue between the bone and devices. We investigated hearing outcomes with percutaneous and transcutaneous devices using test-bands in an induced unilateral conductive hearing loss. DESIGN: Comparison of hearing outcomes of two devices in the same individuals. STUDY SAMPLE: The right ear was plugged in 30 subjects and a test-band with devices (Cochlear™ Baha® BP110 Power and Sophono® Alpha-2 MPO™) was applied on the right mastoid tip with the left ear masked. Sound-field thresholds, speech recognition thresholds (SRTs), and word recognition scores (WRSs) were compared. RESULTS: Aided thresholds of Sophono were significantly better than those of Baha at most frequencies. Sophono WRSs (86 ± 12%) at 40 dB SPL and SRTs (14 ± 5 dB HL) were significantly better than those (73 ± 24% and 23 ± 8 dB HL) of Baha. However, Sophono WRSs (98 ± 3%) at 60 dB SPL did not differ from Baha WRSs (95 ± 12%). CONCLUSION: Amplifications of the current transcutaneous device were not inferior to those of percutaneous devices with a test-band in subjects with normal bone-conduction thresholds. Since the percutaneous devices can increase the gain when fixed to the skull by eliminating the dampening effect, both devices are expected to provide sufficient hearing amplification.

Value of pre-operative caloric test in predicting speech perception after cochlear implantation in adults with post-lingual hearing loss.

CONCLUSION: This study shows that, in cochlear implantation (CI) surgery, pre-operative caloric test results are not correlated with post-operative outcomes of dizziness or speech perception. OBJECTIVES: To determine the role of pre-operative caloric tests in CI. METHODS: The records of 95 patients who underwent unilateral CI were reviewed retrospectively. Patients were divided into four groups according to caloric response. Forty-six patients with normal caloric responses were classified as Group A, 19 patients who underwent CI in the ear with worse caloric responses as Group B, 18 patients with bilateral loss of caloric responses as Group C, and 12 patients who underwent CI in the ear with better caloric responses as Group D. Speech performance and post-operative dizziness were compared between the four groups. Speech perception was determined by evaluating consonant-vowel phoneme detection, closed-set word and open-set mono-syllabic and bi-syllabic word identification, and sentence comprehension test scores. RESULTS: The speech perception and aided pure-tone average (PTA) test results at 3 and 6 months and at 1, 2, and 3 years after implantation were not significantly different between Groups A, B, C, and D (p > 0.05). Eight patients (8.4%) reported post-operative dizziness, but there was no significant difference between the four groups (p = 0.627).

Skull base osteomyelitis missed in mastoidectomy for cholesteatoma.

Conclusions A high suspicion of skull base involvement should be warranted, even if radiological findings are not atypical, in cases of chronic otitis media (COM) with cholesteatoma. Objective To investigate some clues indicating the development of skull base osteomyelitis (SBO) in patients who received mastoidectomy, through reviewing pre-operative temporal bone computed tomography (TBCT). Method Retrospective review of patients with SBO after mastoidectomy for COM. A total of five patients with SBO after mastoidectomy with available pre-operative TBCTs were enrolled in this study. Results All patients were diagnosed as COM with cholesteatoma and open cavity mastoidectomy was performed. After surgery, SBO were occurred. The recovery in these five patients was complicated by lower cranial nerve palsy, and one patient had a stroke due to lateral thrombophlebitis. Through re-interpretation of pre-operative TBCT, the bony destruction around the skull base missed at the initial diagnosis was observed in all cases.