Lateral Semicircular Canal Fistula 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.

Clues for facial canal dehiscence in chronic otitis media

Introduction and objectivesThe goal of this study was to determine the impact of external and middle ear findings in the incidence of facial canal dehiscence (FCD) during mastoidectomy for chronic otitis media. Material and methodsWe examined the operative details of 186 patients who underwent primary tympanomastoidectomy for chronic otitis media between January 2015 and January 2020 retrospectively.In this study we only evaluated the second portion of the facial nerve canal. ResultsThe global prevalence of FCD was 22.6% (42/186 patients) with a higher incidence, of 38.7% (36/93), in patients with chronic otitis media with cholesteatoma (C-COM).Associations were found between facial canal dehiscence, labyrinthine fistula (p˂ .001) and facial nerve paralysis (p˂ .001).Ossicular erosions were observed at a significant level in patients with facial canal dehiscence, the incidence of FCD was significantly higher (p=.005, Odds ratio 5.489) when malleus and incus were eroded, incus plus stapes were eroded (p=.014; OR 4.059) and malleus, incus, and stapes together were eroded (p=.002; OR 4.929). ConclusionsThis study revealed an incidence of facial canal dehiscence of 22.6%. It also revealed that the presence of lateral semicircular canal fistula is associated with a higher prevalence of facial canal dehiscence.The same was noted in the case of some ossicular erosions, especially the combinations of eroded malleus and incus, incus and stapes, and all 3 ossicles.These findings raise awareness about the usefulness of middle ear findings in predicting FCD, thus providing valuable information for the otological surgeon to avoid iatrogenic injuries.

Transcanal endoscopic management of lateral semicircular canal fistula: preliminary experience.

Labyrinthine fistula is one of the most frequent complications of cholesteatoma (CHO), occurring in about 8% of cases in the literature. In about 90% of cases, it is located at the level of the lateral semicircular canal, and its clinical manifestation includes vertigo, nystagmus and positive Hennebert and Tullio signs. The management of lateral semicircular canal fistula (LSCF) secondary to CHO classically requires a retroauricular access by performing a canal wall-up (CWU) or canal wall-down (CWD) mastoidectomy. However, in case of a CHO confined to the tympanic cavity causing a LSCF on the ampullar arm, a transcanal exclusive endoscopic approach could be considered. The aim of this study is to describe the feasibility of a transcanal exclusive endoscopic approach in the management of a CHO confined to the tympanic cavity causing a LSCF on the ampullar arm. From January 2019 to December 2020, three patients with LSCF secondary to mesotympanic CHO underwent transcanal exclusive endoscopic ear surgery repair at the Department of Otolaryngology-Head and Neck Surgery, University Hospital of Modena, Italy. This technique was successfully employed to treat LSCF in all three cases and was planned as a two-stage surgery, performing ossiculoplasty after 12-18 months. Functional outcomes were also satisfactory: complete eradication of CHO, hearing preservation and complete resolution of symptoms. In case of a CHO confined to the tympanic cavity causing an LSCF on the ampullar arm, a transcanal exclusive endoscopic approach could be considered as a feasible and safe technique.

English

BACKGROUND Chronic otitis media (COM) of squamosal type is associated with cholestatoma with potential complications. Clinical examination and high resolution computed tomography (HRCT) scans are necessary to assess the disease site and extension. The purpose of the study was to compare the preoperative HRCT findings with the intraoperative surgical findings in squamosal type of chronic otitis media as well as various parameters in HRCT temporal bone and intraoperative findings. METHODS A prospective study was conducted on 30 patients aged between 18 and 60 years of both the genders who presented with chronic otitis media squamosal type, for a period of 22 months who attended the outpatient department of ENT. RESULTS HRCT findings and intraoperative findings were compared and results were analysed. Facial canal erosion (P - 0.0031), tegmen plate erosion (P - 0.0001), sigmoid sinus plate erosion (P - 0.002) were found to be statistically significant. Lateral semicircular canal fistula (P - 0.36) and ossicular status malleus (P - 1.000), incus (P - 0.949), stapes suprastructure (P - 0.984), and stapes footplate erosion (P - 0.977) were found to be statistically insignificant. CONCLUSIONS In our study, HRCT imaging for COM squamosal type, accurately depicted the soft tissue mass, erosion of tegmen plate, sigmoid sinus plate, scutum, lateral semicircular canal fistula, incus and suprastructure of stapes erosion and the same were found intraoperatively as well. Our study showed good comparison between the preoperative HRCT scans and the surgical findings in cholesteatoma cases. HRCT is confirmed to be valuable in the diagnosis and in guiding the surgical management of cholesteatoma. KEY WORDS Chronic Otitis Media, Cholesteatoma, HRCT Temporal Bone, Modified Radical Mastoidectomy

Role of High Resolution Computed Tomography of Temporal Bone in Patients with Cholesteatoma, in a Tertiary Care Health Center.

The aim of this study is to evaluate the necessity of high resolution computed tomography (HRCT) temporal bone in patients with active squamosal chronic otitis media, by comparing the preoperative HRCT temporal bone findings with intra operative findings in a tertiary care health center where patient load is tremendous.This study was conducted in the department of otorhinolaryngology, over a period of two years from November 2017 to November 2019 in which 100 patients with active squamosal chronic otitis media diagnosed clinically were taken. All patients underwent preoperative HRCT temporal bone and subsequent tympanomastoidectomy.The results of HRCT temporal bone of all the patients were evaluated and correlated with intraoperative findings which revealed that HRCT is highly sensitive for detecting,soft tissue extension, tympanic membrane perforation, ossicular erosion, tegmen erosion, sigmoid sinus erosion, facial canal dehiscence and lateral semicircular canal fistula, which helps in guiding the surgical approach and treatment plan preoperatively.

Intracranial and extracranial complications of chronic otitis media and their management at a tertiary care center: a descriptive study

&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;In the pre-antibiotic era complications from otitis media occurred abundantly, accompanied by high morbidity and mortality. With availability of higher antibiotics, morbidity and mortality due to chronic otitis media (COM) has reduced, but still complications due to COM remain a significant problem in developing countries. The aim is to study clinical presentation, management and outcomes of intracranial and extracranial complications of COM. Study design is retrospective case series study.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods:&lt;/strong&gt; Patients admitted in department of otorhinolaryngology and head and neck surgery, S. Nijalingappa medical college and H.S.K hospital and research center, Bagalkot from May 2018 to April 2020 with COM associated with intracranial or extracranial complications were included in the study. Data of clinical presentation, associated complications, management, and follow-up were analyzed.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results:&lt;/strong&gt; A total of 20 patients were reviewed during study period. Of these seventeen patients had extracranial (EC) complications, while one had intracranial (IC) complications and two had both. Otalgia, otorrhea and fever were the main presenting symptoms. The encountered IC complication were lateral sinus thrombophlebitis, cerebellar abscess. Among the EC complications most common were post-auricular subperiosteal abscess, lateral semicircular canal fistula and facial paralysis. Most commonly isolated organism was staphylococcus. Surgery was main modality of treatment.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; COM is still a significant problem in developing countries in spite of availability of antibiotics and early diagnosis is crucial in the management of complications associated. This study emphasizes the importance of early diagnosis and prompt treatment to limit the morbidity.&lt;/p&gt;

Comparison of preoperative high resolution computerized tomography of temporal bone with intra-operative findings in patients with cholesteatoma

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; Aim was to study the correlation between high resolution computed tomography (HRCT) scan and intraoperative findings during surgery in cases of chronic otitis media with cholesteatoma.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; This was a descriptive study conducted on 72 patients with acquired cholesteatoma at Govt TD Medical College, Alappuzha for a period of 18 months. All the patients were subjected to HRCT of the temporal bone. Radiological correlation was done with the intra-operative findings. Sensitivity, specificity, positive and negative predictive values were calculated. &lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; Total 24 (33.3%) patients had holotympanic cholesteatoma, 21 (29.2%) had involvement of the attic alone and 16 (22.2%) had attic and antrum involved. 100% correlation was found with bony wall erosions, whereas 96.9% and 75% sensitivity were noted in incus and stapes erosions respectively. 100% specificity was obtained in facial canal and sinus plate erosion, while a specificity of 96.9% in tegmen erosion and 98% in were seen in malleus erosion. By chi square test the difference in correlation was not significant (p value&amp;gt;0.01). Good correlation was seen for lateral semicircular canal fistula. Contrast CT is more specific, but MRI with diffusion weighted sequences is the best in imaging cholesteatoma, especially residual lesions. &lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; Good correlation was found between HRCT scan and intra-operative findings in cases of cholesteatoma in relation to bony wall erosion of the surrounding structures. CT scan alone cannot differentiate soft tissue masses.&lt;/p&gt;

Treatment of cholesteatoma associated with a lateral semicircular canal fistula leading to a rapidly progressive inner ear disorder

Treatment of cholesteatoma associated with a lateral semicircular canal fistula leading to a rapidly progressive inner ear disorder

Serum prolidase, malondialdehyde and catalase levels for the evaluation of oxidative stress in patients with peripheral vertigo.

We aimed to evaluate oxidative stress in patients with peripheral vertigo by measuring serum prolidase, malondialdehyde (MDA) and catalase levels. A total of 30 patients (age: 60 <) with peripheral vertigo and 30 healthy subjects were recruited. Blood samples were collected from both groups and serum prolidase levels were measured using enzyme-linked immunosorbent assay (ELISA). MDA and catalase levels were measured by the spectrophotometric method. The most common cause of vertigo was BPPV (53.3%), followed by Ménière's disease (16.6%), vestibular neuritis (13.3%), lateral semicircular canal fistula (3.3%), and idiopathic vertigo (13.3%). Mean serum prolidase activity and MDA levels were significantly higher in the vertigo patients than in the control subjects (P < 0.05); however, there was no statistically significant difference in mean serum catalase levels between the groups (P > 0.05). We concluded that serum prolidase and MDA levels may be used as markers of oxidative stress in patients with peripheral vertigo.

Diagnostic efficacy of high-resolution computed tomography findings in patients of chronic suppurative otitis media atticoantral type

&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;High resolution computed tomography (HRCT) provides information about anatomy and pathology of temporal bone and middle ear cleft, thus becoming important imaging modality in diagnosis and pre-operative planning in patients of chronic suppurative otitis media (attico-antral) CSOM (AA) type. The aim of study was to study disease extension and plan surgery accordingly in patients of CSOM (AA) and to study correlation between the HRCT findings and intra-operative findings of CSOM (AA) like soft tissue density mass, ossicular chain erosion, facial canal dehiscence, semi-circular canal erosion.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;Study of 70 patients clinically diagnosed of having CSOM (AA) in period between August 2018 to March 2020 was done at Sola civil hospital, Ahmedabad. All patients were advised HRCT temporal bone except those who had contraindications to CT scan, analysed and operated. Pre-operative CT-scan findings and intra-operative findings were compared for statistical analysis.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;Soft tissue density was found in 100% of cases on HRCT temporal bone. Bony erosion seen in 25% of cases. 90% showed ossicular erosion. Lateral semi-circular canal fistula was observed in 10% of cases with facial canal dehiscence in 10% of cases. Intra-operative findings showed accuracy of HRCT in detecting soft tissue density to be 100%; bony erosion was observed in 25% cases. 10% patients had lateral semi-circular canal fistula. Facial canal dehiscence was seen in 15% cases.&lt;/p&gt;&lt;strong&gt;Conclusion: &lt;/strong&gt;HRCT has proved quite useful and reliable to identify the disease extension before surgery and plan surgery accordingly.&lt;p&gt; &lt;/p&gt;

Relationship between Eustachian Tube Dimensions and Middle Ear Cholesteatoma

Objective: To compare intact and diseased ears for Eustachian tube (ET) length and width in patients with unilateral chronic otitis media (COM), and to assess the relationship between cholesteatoma spread, stapes erosion, lateral semicircular canal (LSCC) fistula and ET width and length retrospectively. Methods: Subjects with unilateral COM (122 subjects with 244 ears) who underwent surgery for cholesteatoma were evaluated retrospectively for this study. The width of the distal orifice of the bony segment and the length of the bony segment of the ET for both the diseased and healthy ear were measured. Subjects’ healthy and diseased ears were compared for ET length and width. The diseased sides were compared to assess the relationship between ET dimensions and cholesteatoma spread, stapes erosion and LSCC fistula. Results: The mean ET length and width in healthy and diseased ears was 11.38±1.7 and 1.43±0.37 mm, and 10.99±1.6 and 1.27±0.35 mm, respectively; the difference was statistically significant (p<0.001). No significant differences were found in terms of ET length and width between the subjects with and without stapes erosion and LSCC fistula (p=0.765, p=0.573, and p=0.436, p=0.790, respectively). No significant relation was found between cholesteatoma spread and ET length and width (p=0.647). Conclusion: ET dysfunction is frequently associated with COM. Chronic otitis media with cholesteatoma is significantly related to ET length and width. Measurement of ET length and width in CT scans is a basic method that can be used in clinical practice.

The Medially-Invasive Cholesteatoma: An Aggressive Subtype of a Common Pathology.

Describe the outcomes of treatment for patients with cholesteatomas that are medially invasive to the otic capsule, petrous apex, and/or skull base. Retrospective case series. Two tertiary care academic centers. Patients surgically managed for medially-invasive cholesteatoma at two tertiary care institutions from 2001 to 2017. Surgical management of medially-invasive cholesteatomas. The presenting symptoms, imaging, pre- and post-operative clinical course, and complications were reviewed. Seven patients were identified. All patients had pre-operative radiographic evidence of invasive cholesteatoma with erosion into the otic capsule beyond just a lateral semicircular canal fistula. Five patients had a complex otologic history with multiple surgeries for recurrent cholesteatoma including three with prior canal wall down mastoidectomy surgeries. Average age at the time of surgery was 41.3 years (range 20-83). Two patients underwent a hearing preservation approach to the skull base while all others underwent a surgical approach based on the extent of the lesion. Facial nerve function was maintained at the pre-operative level in all but one patient. No patient developed cholesteatoma recurrence. The medially-invasive cholesteatoma demonstrates an aggressive, endophytic growth pattern, invading into the otic capsule or through the perilabyrinthine air cells to the petrous apex. Surgical resection remains the best treatment option for medially-invasive cholesteatoma. When CSF leak is a concern, a subtotal petrosectomy with closure of the ear is often necessary.

Prevalence of facial canal dehiscence and other bone defects by computed tomography.

The facial nerve is the most vulnerable structure during otological surgeries. Facial canal dehiscence (FCD) is the main risk factor for iatrogenic injuries. Its prevalence in clinical studies ranges between 6 and 33.3%, while anatomical studies report 25-57%. The objective was to determine the prevalence of FCD stratified by age and gender in a healthy population. Temporal bones from high-resolution computed tomography (CT) were analyzed. Patients with a history of trauma or tumors of the temporal bone, cholesteatomas, chronic middle ear disease, and any pathology that could modify the bone's anatomy, were excluded. A total of 184 temporal bones were included. FCD was observed in 94 (51.2%) of the analyzed bones. The tympanic portion was the most frequently affected site with 91 (49.5%), followed by the mastoid segment with 3 (1.6%). No dehiscence was found in the labyrinth portion. We observed 30 (31.9%) of the FCD involved the oval window. Other bone defects identified with the FCD included: 11 (11.7%) with a lateral semicircular canal fistula and 7 (7.4%) with tegmen tympani erosions. FCD has a high prevalence among healthy patients. A pre-surgical otological evaluation using high-resolution CT should be indicated to properly assess the patient and reduce the risk of injury.

Middle-ear cholesteatoma co-existing with labyrinthine fistula and vestibular schwannoma

BackgroundMany conditions, among them vestibular schwannoma and middle ear cholesteatoma with lateral semicircular canal destruction, may be associated with asymmetrical sensorineural hearing loss (SNHL) and vertigo. However, the probability that these two distinct disease entities causing the same symptoms occur in a single patient is very low, approximately 1 per 28 billion per 1 year.MethodsWe present the case of a 40-year-old male admitted to our clinic because of chronic middle ear inflammation with concomitant tinnitus vertigo, and deafness in the right ear. The patient was diagnosed with lateral semicircular canal fistula caused by middle-ear cholesteatoma and concomitant vestibular schwannoma. Canal wall-down surgery was carried out to remove the cholesteatoma, followed by gamma knife radiosurgery for the vestibular schwannoma.ResultsVertigo and tinnitus resolved within 3 days after the ear surgery, and gamma knife treatment resulted in the complete involution of the vestibular schwannoma. The patient presented with completely dry middle-ear cavity and no recurrence of the cholesteatoma was observed during a 3-year follow-up.ConclusionAs the hereby reported condition is very rare, the results cannot be compared with any similar report published previously. Nevertheless, based on the outcome, the treatment strategy seems to be both reasonable and effective.

Video Head Impulse Test in Labyrinthine Fistula due to Middle Ear Cholesteatoma.

To assess and monitor lateral semicircular canal (LSC) function over time in patients affected by chronic otitis media with cholesteatoma (CHO) complicated by fistula of LSC (LSC-F) before and after surgery using video Head Impulse Test (vHIT). Eight patients aged 18-67 years affected by CHO with imaging-ascertained LSC-F were included in this preliminary prospective study. The following protocol has been applied: oto-microscopic diagnosis with patient's history; computed tomography scan of the temporal bone; surgery with concomitant resurfacing of LSF-F; audiological and vestibular evaluation before surgery (T0) and at 30 days (T1), 6 months (T2), and 1 year after surgery (T3). vHIT was used to assess vestibulo-ocular reflex (VOR) in LSC. None of the patients showed deterioration of bone conduction hearing levels during the different time of evaluation. Three patients showed a reduced VOR gain and catch-up saccades at T0, with VOR gain normalization at T2. This finding remained stable at the 1-year follow-up. The VOR gain in the nonaffected side generally experienced an increase, paralleled by the normalization on the affected side, with statistically significant correlation. The subjects with normal vHIT before surgery did not show any variation following surgery. vHIT allows the assessment of LSC function in case of fistula. The adopted surgical fistula repair did not induce deterioration of the auditory or LSC function, but indeed, it could prevent worsening and help promoting recovery to the normal function.

Cholesteatoma labyrinthine fistula: prevalence and impact

IntroductionLabyrinthine fistula is one of the most common complications associated with cholesteatoma. It represents an erosive loss of the endochondral bone overlying the labyrinth. Reasons for cholesteatoma-induced labyrinthine fistula are still poorly understood. ObjectiveEvaluate patients with cholesteatoma, in order to identify possible risk factors or clinical findings associated with labyrinthine fistula. Secondary objectives were to determine the prevalence of labyrinthine fistula in the study cohort, to analyze the role of computed tomography and to describe the hearing results after surgery. MethodsThis retrospective cohort study included patients with an acquired middle ear cholesteatoma in at least one ear with no prior surgery, who underwent audiometry and tomographic examination of the ears or surgery at our institution. Hearing results after surgery were analyzed according to the labyrinthine fistula classification and the employed technique. ResultsWe analyzed a total of 333 patients, of which 9 (2.7%) had labyrinthine fistula in the lateral semicircular canal. In 8 patients, the fistula was first identified on image studies and confirmed at surgery. In patients with posterior epitympanic and two-route cholesteatomas, the prevalence was 5.0%; and in cases with remaining cholesteatoma growth patterns, the prevalence was 0.6% (p=0.16). In addition, the prevalence ratio for labyrinthine fistula between patients with and without vertigo was 2.1. Of patients without sensorineural hearing loss before surgery, 80.0% remained with the same bone conduction thresholds, whereas 20.0% progressed to profound hearing loss. Of patients with sensorineural hearing loss before surgery, 33.33% remained with the same hearing impairment, whereas 33.33% showed improvement of the bone conduction thresholds’ Pure Tone Average. ConclusionLabyrinthine fistula must be ruled out prior to ear surgery, particularly in cases of posterior epitympanic or two-route cholesteatoma. Computed tomography is a good diagnostic modality for lateral semicircular canal fistula. Sensorineural hearing loss can occur post-surgically, even in previously unaffected patients despite the technique employed.

Chronic otitis media with cholesteatoma with canal fistula and bone conduction threshold after tympanoplasty with mastoidectomy.

To understand the third mobile window effect of chronic otitis media with cholesteatoma with inner ear fistula on the bone conduction threshold, we examined changes in the bone conduction audiogram after tympanoplasty with mastoidectomy for chronic otitis media with cholesteatoma with canal fistula. Retrospective case review. Tertiary referral center. According to the intraoperative classification of Dornhoffer and Milewski, we focused especially on Type IIa (anatomic bony fistula with no perilymph leak). We checked the bone conduction threshold at least 3 times: just before, just after, and 6 months after surgery in 20 ears with Type IIa lateral semicircular canal fistula. Tympanoplasty with mastoidectomy. Bone conduction thresholds before and after tympanoplasty with mastoidectomy. Compared with the preoperative bone conduction threshold, 6 cases were better, 12 cases were unchanged, and 2 cases were worse within the first postoperative week. Finally, 1 case was better, 15 cases were unchanged, and 4 cases were worse at the sixth postoperative month. Patients with a better bone conduction threshold in the low-tone frequencies immediately after surgery had a tendency to show no preoperative fistula symptoms. Postoperative spontaneous nystagmus had a tendency to be observed in patients with a worse bone conduction threshold in the high-tone frequencies. The better bone conduction threshold at low-tone frequencies immediately after tympanoplasty with mastoidectomy and no preoperative fistula symptoms might imply the third mobile window theory. The worse bone conduction threshold in high-tone frequencies with spontaneous nystagmus after surgery might indicate inner ear damage.

Relationships between facial canal dehiscence and other intraoperative findings in chronic otitis media with cholesteatoma

ObjectiveWe investigated the relationship between facial canal dehiscence and intraoperative middle ear and mastoid findings in patients operated on for cholesteatoma. MethodsWe examined retrospectively 334 patients who had been operated on for cholesteatoma in Izmir Katip Celebi University, Ataturk Research and Training Hospital, ENT Clinic, between April 1997 and April 2010. The patients were examined for facial canal dehiscence according to age, gender, side of the ear, surgery type, first or revision surgery, localization of the facial canal dehiscence, spread of the cholesteatoma, with the presence of lateral semi-circular canal (LSCC) fistula and any defect in the ossicle chain, and destruction in the posterior wall of the external auditory canal(EAC). ResultsOf the patients, 23.6% had facial canal dehiscence and detected most commonly in the right ear 28.9% and tympanic segment, 83.5%. Facial canal dehiscence was found to be 24.2-fold more common in patients with LSCC fistula and 4.1-fold more common in patients with destruction in the posterior wall of the (EAC). In patients located cholesteatoma in tympanic cavity+antrum and the tympanic cavity+all mastoid cells and with incus and stapes defect, increased incidence of dehiscence. Age, first or revision operation and canal wall down tympanoplasty (CWDT) or canal wall up tympanoplasty (CWUT) did not affect the incidence of dehiscence. ConclusionsThat the likelihood of facial canal dehiscence occurrence is increased in patients with LSSC fistulas, destruction in the posterior wall of the EAC, or a stapes defect is important information for surgeons.

小脳膿瘍の原因となった真珠腫性中耳炎例

A case of bilateral cholesteatomas which caused a cerebellar abscess is reported herein. The patient was a 38-year-old male who had bilateral otorrhea and hearing loss from childhood. He presented with fever, a headache, and vertigo which had started in the summer, and he visited our hospital 2 months later because the symptoms did not improve. At the first visit, nystagmus was not present. CT images revealed bilateral cholesteatomas, and there was a lateral semicircular canal fistula with expansion of the cochlea and the posterior semicircular canal in the right ear. There was no bone defect of the middle- and post-cranial fossa. At first, we regarded the vertigo as peripheral, and planned a radical operation on the right middle ear. But, after hospitalization, the patient collapsed with a tendency to somnolence and Bruns’ nystagmus. MRI revealed an abscess in the right cerebellar hemisphere. To treat obstructive hydrocephalus and the cerebellar abscess, trepanning ventricular drainage and brain abscess drainage via a craniotomy were carried out. After treatment with antibiotics, the patient’s general state improved. Accordingly, a mastoidectomy with labyrinthectomy was performed on the right ear, and a staged tympanoplasty was carried out on the left ear. There has been no recurrence for 3 years until the time of writing. We presume that the infection route of this case was the internal auditory meatus. A cerebellar abscess secondary to cholesteatoma is rare, but early examination and treatment are necessary, because the fatality rate in these cases is higher when a brain, especially cerebellar abscess occurs.

Clinical and Radiographic Predictors of Lateral Semicircular Canal Fistula

Objectives: Lateral semicircular canal fistula (LSCCF) may occur in as many as 10% of patients with cholesteatoma. Despite improvements in diagnostic imaging, reliable preoperative identification of LSCC remains elusive. Our objective is to explore preoperative clinical variables and intraoperative findings in order to identify factors associated with the presence of LSCCF. Methods: A retrospective matched cohort study was conducted. All patients with LSCCF, determined by intraoperative diagnosis, that had preoperative temporal bone computed tomography (CT) available for review were identified. Subjects were matched to patients without LSCCF according to age, gender and year of surgery. Associations between LSCCF and preoperative vertigo, fistula test results, sensorineural hearing loss (SNHL), stapes superstructure erosion, facial nerve and dural dehiscence, and preoperative radiographic findings were evaluated. Results: Eighty-three patients with LSCCF met inclusion criteria and were matched to subjects without labyrinthine fistula. Patients with LSCCF more commonly had stapes superstructure erosion (34 vs 15, P &lt; .001), facial nerve dehiscence (55 vs 10, P &lt; .0001), and dural dehiscence (29 vs 4, P &lt; .0001) compared to subjects without LSCCF. The presence and severity of preoperative SNHL, vertigo, and fistula test results were unreliable predictors of LSCCF. Furthermore, of those patients with LSCCFs, only 28% were identified on pre-operative CT. Conclusions: Preoperative variables including SNHL, vertigo, fistula test results as well as preoperative temporal bone CT were not reliable predictors of LSCCF. However, intraoperative findings including stapes superstructure erosion, facial nerve and dural dehiscence were found to be associated with LSCCF and should raise suspicion of disease.