Semicircular Canal Defect Research Articles

Cholesteatoma Surgery With Three Different Methods: A Clinical Study For Recidivism Research

Introduction: The study aimed to determine the rates of recidivistic disease after primary surgery, localization of cholesteatoma, pathologic findings detected during the operation, and the additional surgical procedures performed in patients with chronic otitis media with cholesteatoma. Materials and Methods: Three hundred forty-five patients suspected of chronic otitis media with cholesteatoma searched their files and operation notes in Cukurova University Hospital between January 2010 and January 2020 retrospectively. Three surgical techniques were applied: Canal Wall Down (CWDM), Canal Wall Up (CWUM), and Radical (RM) mastoidectomy. Cholesteatoma localization, ossicular system status, condition of the facial canal, semicircular canal defects, tegmen defect, tympanoplasty, and whether hearing reconstruction is performed were investigated. In follow-up, revision surgeries were performed on 61 patients with suspicions of recidivistic disease. The revision surgery region was where cholesteatoma was detected, and the condition of the ossicles was investigated. Patients' demographic characteristics, follow-up time, the recidivism rate in surgical method, cholesteatoma localization in the first surgery, and cholesteatoma localization in revision surgery were compared. Results: 27.2% of 345 patients were CWUM, 23.5% were CWDM, and 49% were RM. Cholesteatoma localization was 60.9% of them in mastoid cavities, 59,4% of them in the attic and epitympanum, 56,2% of them in the middle ear, and 12,8% of them in only sinus tympani and facial recesses. Patients were followed for a mean of 36 months. In the follow-up period, revision mastoidectomy was performed for ten patients with recidivistic disease. Revision rates after CWUM were 62,3%, revision rates after CWDM were 9,8%, and revision rates after RM was 27,9%. Conclusions. The choice of surgical procedure is an essential parameter in forming a recidivistic disease. Especially in open technical surgeries (CWDM and RM), the risk of recidivistic disease is significantly lower than that of closed technical surgeries (CWUM). Keywords: Cholesteatoma, recidivistic disease, ossicle erosion, radical mastoidectomy

Total Transcanal Endoscopic Ear Surgery for Cholesteatoma.

This study aimed to evaluate the outcomes of total transcanal endoscopic cholesteatoma surgery. Twenty-seven cholesteatoma patients that had undergone transcanal endoscopic ear surgery (TEES) were included in the study. Age, sex, operation date of patients, operated side, need for ossiculoplasty, graft material, and surgical technique were recorded. All patients were evaluated through otoscopic, endoscopic, and audiological examinations and followed up for at least five months after surgery. All patients were staged using the European Academy of Otology and Neurotology/Japan Otological Society (EAONO/JOS) Staging System on Middle Ear Cholesteatoma. Mean age of the patients was 36.4 years (range, 4-67 years). According to the EAONO/JOS Staging System, 11 patients were stage 1, while 11 were stage 2, and five were stage 3. Two had lateral semicircular canal defect, one had facial canal dehiscence, and one had oval window defect. The average follow-up period was 19 months (range, 5-41 months), during which two patients experienced retraction pocket and hearing loss and one patient had perforation. One patient underwent revision surgery during follow-up and no recurrence or residual cholesteatoma was observed. The preoperative and postoperative air-bone gaps were 25.14±13.93 dB and 22.22±12.64 dB with no significant difference. TEES is a minimally invasive and safe procedure with low complication and recurrence rates. As with all surgical procedures, experience is essential, and as experience increases, the capability to perform endoscopic otologic surgery on more complex cases may become possible.

Transmastoid approach for surgical repair of superior canal dehiscence syndrome

Patients with superior canal dehiscence syndrome may present with a myriad of auditory and/or vestibular complaints. Treatment of superior canal dehiscence syndrome depends on severity of symptoms and impact on quality of life. Surgery is recommended for patients with debilitating auditory and/or vestibular symptoms. The goal of surgery is to create a durable and watertight seal of the bony superior semicircular canal defect, thereby eliminating the “third window”. Repair involves either resurfacing and/or plugging of the dehiscent superior canal to eliminate the third window and reduce symptoms. Surgical options include middle fossa craniotomy or transmastoid (TM) approach. The main advantages of a TM approach includes (1) avoidance of a craniotomy, (2) lower risk of CSF leak, and (3) no brain retraction. The TM approach is ideal for superior petrosal sinus superior canal dehiscence cases as the defect is found medial along the skull base and can be isolated indirectly without direct manipulation of the brain and sinus. This chapter discusses the surgical technique of TM approach.

Celsr1 coordinates the planar polarity of vestibular hair cells during inner ear development

Vestibular hair cells of the inner ear are specialized receptors that detect mechanical stimuli from gravity and motion via the deflection of a polarized bundle of stereocilia located on their apical cell surfaces. The orientation of stereociliary bundles is coordinated between neighboring cells by core PCP proteins including the large adhesive G-protein coupled receptor Celsr1. We show that mice lacking Celsr1 have vestibular behavioral phenotypes including circling. In addition, we show that Celsr1 is asymmetrically distributed at cell boundaries between hair cells and neighboring supporting cells in the developing vestibular and auditory sensory epithelia. In the absence of Celsr1 the stereociliary bundles of vestibular hair cells are misoriented relative to their neighbors, a phenotype that is greatest in the cristae of the semicircular canals. Since horizontal semi-circular canal defects lead to circling in other mutant mouse lines, we propose that this PCP phenotype is the cellular basis of the circling behavior in Celsr1 mutants.

Prominent scapulae mimicking an inherited myopathy expands the phenotype of CHD7-related disease.

CHD7 variants are a well-established cause of CHARGE syndrome, a disabling multi-system malformation disorder that is often associated with deafness, visual impairment and intellectual disability. Less severe forms of CHD7-related disease are known to exist, but the full spectrum of phenotypes remains uncertain. We identified a de novo missense variant in CHD7 in a family presenting with musculoskeletal abnormalities as the main manifestation of CHD7-related disease, representing a new phenotype. The proband presented with prominent scapulae, mild shoulder girdle weakness and only subtle dysmorphic features. Investigation revealed hypoplasia of the trapezius and sternocleidomastoid muscles and semicircular canal defects, but he did not fulfill diagnostic criteria for CHARGE syndrome. Although the shoulders are often sloping and anteverted in CHARGE syndrome, the underlying neuromuscular cause has never been investigated. This report expands the phenotypes associated with CHD7 mutations to include a musculoskeletal presentation, with hypoplasia of the shoulder and neck muscles. CHD7 should be considered in patients presenting in childhood with stable scapular winging, particularly if accompanied by dysmorphic features and balance difficulties.

Three-Dimensional Printed Prosthesis for Repair of Superior Canal Dehiscence.

Outcomes following repair of superior canal dehiscence (SCD) are variable, and surgery carries a risk of persistent or recurrent SCD symptoms, as well as a risk of hearing loss and vestibulopathy. Poor outcomes may occur from inadequate repair of the SCD or mechanical insult to the membranous labyrinth. Repair of SCD using a customized, fixed-length prosthesis may address current operative limitations and improve surgical outcomes. We aim to 3-dimensionally print customized prostheses to resurface or occlude bony SCD defects. Dehiscences were created along the arcuate eminence of superior semicircular canals in cadaveric temporal bones. Prostheses were designed and created using computed tomography and a 3-dimensional printer. The prostheses occupied the superior semicircular canal defect, reflected in postrepair computed tomography scans. This novel approach to SCD repair could have advantages over current techniques. Refinement of prosthesis design and materials will be important if this approach is translated into clinical use.

Delayed fusion and altered gene expression contribute to semicircular canal defects in Chd7 deficient mice

Proper morphogenesis of inner ear semicircular canals requires precise regulation of cellular proliferation, epithelial-to-mesenchymal transition, and fusion of epithelial plates. Epigenetic regulation of these processes is not well understood, but is likely to involve chromatin remodeling enzymes. CHD7 is a chromodomain-containing, ATP dependent helicase protein that is highly expressed in the developing ear and is required for semicircular canal development in both humans and mice. Here we report that mice with heterozygous loss of Chd7 function exhibit delayed semicircular canal genesis, delayed Netrin1 expression and disrupted expression of genes that are critical for semicircular canal formation (Bmp2, Bmp4, Msx1 and Fgf10). Complete loss of Chd7 results in aplasia of the semicircular canals and sensory vestibular organs, with reduced or absent expression of Otx1, Hmx3, Jagged1, Lmo4, Msx1 and Sox2. Our results suggest that Chd7 may have critical selector gene functions during inner ear morphogenesis. Detailed analysis of the epigenetic modifications underlying these gene expression changes should provide insights into semicircular canal development and help in the design of therapies for individuals with inner ear malformations.

Superior Canal Dehiscence Syndrome Associated With the Superior Petrosal Sinus in Pediatric and Adult Patients

To determine whether pediatric and adult patients with superior canal dehiscence (SCD) at the superior petrosal sinus (SPS) develop superior canal dehiscence syndrome (SCDS). Retrospective review. Tertiary care academic medical center. Pediatric and adult patients with SPS-associated SCD were identified from a database of 131 patients with SCD based on high-resolution temporal bone computed tomography. One pediatric patient experienced incapacitating exercise-induced vertigo, and this patient's superior semicircular canal defect was plugged via a transmastoid approach. The 11 remaining patients were managed by observation. Clinical symptoms and signs, audiologic testing, vestibular evoked myogenic potentials, and radiologic data. Twelve patients, aged 15 to 84 years, with SCD caused by the SPS contacting the superior semicircular canal were identified. The most characteristic clinical feature in this population (5/12) was dizziness related to exercise and exertion. Bilateral SCD was observed in 3 patients. Eleven patients did not have severe symptoms and were managed conservatively. One patient, aged 15, required surgical intervention for incapacitating vertigo and experienced relief of symptoms with reversal of diagnostic indicators postoperatively. This is the first reported surgical repair of SCDS in a pediatric patient. This is the first series of patients who have SCDS due to contact of the SPS with the superior semicircular canal. Exercise and exertion-related symptoms are common in patients who have SCD owing to this cause. Transmastoid superior canal plugging is feasible and successful in treating SCDS in the pediatric patient.

The Correlation of Temporal Bone CT With Surgery Findings in Evaluation of Chronic Inflammatory Diseases of The Middle Ear

Aim: Computerized tomography (CT) examination of temporal bone is a routine procedure in the diseases of the middle ear. The aim of this study is to establish the efficacy of CT in the diagnosis of the complications due to inflammatory pathologies of middle ear. Method: Patients with suspected middle ear pathology were undergone temporal CT examination between August 2006- June 2008. 56 patients who underwent operation with various complications due to chronic otitis media and choleostatoma were included in the study group. Complications that developed chronic inflammation secondary were established as tympanosclerosis, ossicle erosion, scutum erosion, tegmen erosion, irregularity in mastoid bone cortex and contour of facial nerve, semicircular canal defect and chronic mastoiditis. Result: Sensitivity, specificty, positive and negative predictive value of complications were 84.6%, 88.3%, 68.7% and 95% for timpanosclerosis, 80%, 46.1%, 83.3% and 42% for ossicle erosion, 80%, 90.4%, 84.8% and 73.7% for scutum erosion, 0%, 97.7%, 0% and 80% for tegmen erosion, 40%, 97.8%, 80% and 88.2% for irregularity in mastoid bone cortex, 66.6%, 98%, 80% and 96.07% for irregularity in bone contour of facial nerve, 45.4%, 95.5%, 71.4% and 87.7% for SSC defect, 0.02%, 100%, 100% and 27.2% for chronic mastoiditis. Conclusion: In the evaluation of the complications, surgical findings were highly compatible with tympanosclerosis, ossicle erosion, scutum erosion, irregularity in bone contour of facial nerve. However, CT findings were inconsistent with surgical findings in terms of tegmen erosion, irregularity in mastoid bone cortex, chronic mastoiditis, SSC defects. We suggest that these inconsistencies were related to the surgical technique and CT limitations.

Posterior semicircular canal dehiscence in asymptomatic ears

Conclusions: This study revealed that, in the adult population, the final diagnosis of this entity can only be made by combining imaging with clinical tests. Objective: We developed the largest temporal bone multislice computed tomography (CT) scan study so far by including 410 cases to investigate the prevalence of posterior semicircular canal dehiscence in patients with symptoms unrelated to the inner ear. Methods: A prospective study was performed in 410 consecutive adult individuals who underwent temporal bone multislice CT scan examinations. Results: The prevalence of posterior semicircular canal dehiscence was determined to be 1.2%. No superior or lateral semicircular canal defect was detected in these five patients. All cases with posterior semicircular canal defect were male. In two cases the canal was located unilaterally, while in three cases the defects were present bilaterally. Otological examination and audiovestibular tests revealed no abnormal findings in any of the individuals.

Defects in vestibular sensory epithelia and innervation in mice with loss of Chd7 function: Implications for human CHARGE syndrome

CHD7 is a chromodomain gene mutated in CHARGE syndrome, a multiple anomaly condition characterized by ocular coloboma, heart defects, atresia of the choanae, retarded growth and development, genital hypoplasia, and ear defects including deafness and semicircular canal dysgenesis. Mice with heterozygous Chd7 deficiency have circling behavior and semicircular canal defects and are an excellent animal model for exploring the pathogenesis of CHARGE features. Inner ear vestibular defects have been characterized in heterozygous Chd7-deficient embryos and early postnatal mice, but it is not known whether vestibular defects persist throughout adulthood in Chd7-deficient mice or whether the vestibular sensory epithelia and their associated innervation and function are intact. Here we describe a detailed analysis of inner ear vestibular structures in mature mice that are heterozygous for a Chd7-deficient, gene-trapped allele (Chd7(Gt/+)). Chd7(Gt/+) mice display variable asymmetric lateral and posterior semicircular canal malformations, as well as defects in vestibular sensory epithelial innervation despite the presence of intact hair cells in the target organs. These observations have important functional implications for understanding the clinical manifestations of CHD7 mutations in humans and for designing therapies to treat inner ear vestibular dysfunction.

Circling behavior in the Ecl mouse is caused by lateral semicircular canal defects.

The epistatic circler mouse (Ecl mouse) is a preexisting mutant, which displays a circling phenotype and hyperactivity. It has been shown that the circling phenotype in this mutant results from a complex inheritance pattern, but the vestibular pathology has not been analyzed. The present study deals with the morphological and functional basis responsible for the circling behavior in the Ecl mouse. Morphological examination of the inner ears revealed a bilateral malformation of the horizontal (lateral) semicircular canal and duct. No cochlear abnormalities were detected, and auditory brainstem response (ABR) measurements indicated that the auditory system is not affected. Investigation of the vestibuloocular reflex (VOR) in Ecl mice showed that their horizontal VOR on stimulation is virtually absent, which correlates with the morphological findings.

ENU mutagenesis reveals a highly mutable locus on mouse Chromosome 4 that affects ear morphogenesis

Chemical mutagenesis followed by screening for abnormal phenotypes in the mouse holds much promise as a method for revealing gene function. This method is particularly well-suited for discovering genes involved in hearing or balance function, as these defects are relatively easy to screen for in the mouse. We report here the inner ear abnormalities and genetic localization of seven new dominant mutations created by ENU mutagenesis. All seven mutant stocks were identified because of circling and/or head-weaving behavior, which is an indication of balance dysfunction. Investigation of the inner ears of the seven mutant stocks revealed very similar lateral and posterior semicircular canal defects. Studies of the development of the canals in one mutant stock revealed that the affected canals showed reduced outgrowth and delayed canal fusion. Physiological studies performed in one mutant stock showed raised average compound-action-potential thresholds of approximately 10-20 dB sound pressure level (SPL) (depending on frequency), indicating a mild hearing impairment, although scanning electron microscopy performed in several of the mutant stocks revealed no obvious structural defects in the organ of Corti. All seven mutations mapped to the proximal portion of Chromosome (Chr) 4, near the centromere. On the basis of their similar phenotype and map location, we suggest that the seven mutant genes may be allelic and represent a highly mutable locus on Chr 4 that may be particularly susceptible to ENU-induced mutation on the BALB/c genetic background.