Implantable Hearing Devices in Ontario: A Population-Based Study of Access to Care and Access to Devices.

INTRODUCTION: The prevalence of hearing loss in Canada is high, with many patients requiring implantable hearing devices (IHDs) as treatment for their disease severity. Despite this need, many eligible patients do not pursue these interventions. The objective of this study was to examine rates of IHD based on geographic location to understand locoregional variation in access to care. STUDY DESIGN: This was a retrospective population-based cohort study. SETTING: All hospitals in the Canadian province of Ontario. METHODS: Of all patients with IHD between April 1, 1992, and March 31, 2021, cochlear implants (CIs) (4,720) and bone-anchored hearing aids (BAHA) (1,125) cohorts were constructed. Place of residence was categorized based on Local Health Integrated Network (LHIN). Summary statistics for place of surgical institution based on LHIN at first surgery, name of institution of first surgery and "as the crow flies" distance (in km) between place of residence and surgical institution were calculated. Rate of implantations was calculated for LHIN regions based on number of surgeries per 1,000,000 persons/years. RESULTS: Toronto Central, Central, Central East, and Champlain regions had >10% of patients undergoing BAHA and CI. 1,019 (90.6%) and 4,232 (89.7%) of patients receiving BAHA and CI, respectively, resided in urban/suburban regions and 94 patients (8.4%) and 436 (9.2%) resided in rural regions. The median distance between residential location and the institution was 46.4 km (interquartile range [IQR], 18.9-103.6) and 44.7 km (IQR, 15.7-96.9) for BAHA and CI, respectively. From 1992 to 2021, the number of CI and BAHA performed across Ontario increased by 17 folds and 6 folds, respectively. CONCLUSION: This large comprehensive population study provides longitudinal insight into the access to care of IHD based on geographic factors. Our findings of the present population-based study indicate an overall increase in access to devices with disproportionate access to care based on geographic locations. Further work is needed to characterize barriers to IHD access to align with demands.

Transcanal endoscopic ear surgery for glomus tympanicum removal: A case series on the necessity of preoperative embolization.

BACKGROUND: Transcanal endoscopic ear surgery (TEES) has become popular in recent years in the treatment of glomus tympanicum tumors (GTT). The most significant risk for TEES is bleeding. In some cases, preoperative vascular embolization is performed to mitigate bleeding during TEES. However, guidelines regarding the necessity and efficacy of preoperative vascular embolization have not been established yet. CASE PRESENTATION: This report aimed to assess the necessity and usefulness of preoperative vascular embolization in TEES for GTT by comparing the surgical findings of TEES without preoperative vascular embolization (Case 1) and TEES with preoperative vascular embolization (Case 2). Compared to Case 1, Case 2 included less bleeding and a more convenient procedure. However, no significant difference was observed. CONCLUSIONS: For GTT confined to the middle ear cavity (Glasscock-Jackson Grade II or less), when performed by a proficient otolaryngologist, TEES alone is sufficient without preoperative vascular embolization.

Bone cement repair of malleus handle fractures: Intraoperative video and case report of two patients.

Isolated malleus fractures are a rare occurrence with few reported cases in the literature. Symptoms include sudden otalgia, hearing loss, tinnitus and aural fullness. Work-up and diagnosis are based on a combination of thorough anamnesis and careful otoscopic evaluation or high-resolution computer tomography. We present two cases of isolated malleus handle fractures who were diagnosed based on a combination of pneumatic otoscopy and tympanometry. Both fractures were surgically repaired using hydroxyapatite bone cement as showcased in the supplemental video material. Post-operative audiometry showed improvement in the pure-tone-average of both patients as well as normalisation of tympanometry. Isolated malleus fracture should be suspected in cases of sudden hearing loss and tinnitus following digital manipulation of the outer ear canal together with a conductive hearing loss with a mostly high-frequent air-bone-gap and hypercompliant tympanometry with hypermobility of the tympanic membrane on pneumatic insufflation. Surgical repair of the fracture using bone cement has good hearing outcomes and leads to improvement in auditory symptoms.

Comparison of capabilities and limitations of endoscopes in endoscopic ear surgeries using 3D printed models.

PURPOSE: Endoscopic ear surgery has become a popular operative approach to treat middle ear diseases. Surgeons use either 0° or 30° endoscopes worldwide. The main aim of the work was to compare the properties of these two types of endoscopes. MATERIAL AND METHODS: Since this type of evaluation is hard to perform in vivo during the actual surgery, we designed 3D printed temporal bone models with different levels of complexity. The evaluation of endoscopes was based on image analysis or visibility of anatomical structures. RESULTS: The results show that a 30° endoscope offers a view of lateral walls from 4 mm distance, contrary to a 0° endoscope which cannot see lateral walls from this distance at all. On the other hand, visible area of the anterior wall is up to 40 % larger using 0° endoscope, compared to 30° endoscope. Angled endoscope distorts the picture and leads to the deterioration of the image. At commonly used distances above 5 mm from middle ear structures, resolution and image distortion is comparable between both endoscopes. CONCLUSIONS: Our results do not offer a definitive opinion on which endoscope is better for ear surgery. Both types of endoscopes have advantages and disadvantages, and the choice depends on the surgeon's personal preference and on the type of planned procedure.

Hearing rehabilitation in children with malformed ears: The endoscopic-assisted approach for cochlear implantation.

BACKGROUND: Cochlear implantation (CI) in children with malformed ears can be challenging through the standard surgical technique. Several alternative approaches have been described. The endoscopic-assisted approach can be chosen as an effective and safe surgical technique, overcoming the drawbacks of the traditional approach. MATERIAL: We further describe a combined technique based on a limited mastoidectomy with no posterior tympanotomy and an endoscopic transmeatal approach to the round window (RW): the electrode is driven from the mastoid to the middle ear through the attic. RESULTS: The concomitant endoscopic assistance allows for improved surgical vision, reducing the risk of major complications. The main advantages of this technique are related to better visualization of the RW for safe insertion of the electrode; avoidance of damage to the facial nerve (FN), due to direct visualization, and sparing the posterior tympanotomy; avoidance of subtotal petrosectomy, if not necessary. CONCLUSION: The purpose of this article, supported with a video file, is to describe step by step this endoscopic-assisted procedure in a patient with middle ear malformation.

Preliminary investigation of endoscopic surgery for tympanic membrane perforation: Regenerative treatment compared with conventional surgery.

PURPOSE: To compare surgical outcomes of regenerative treatment (RT) including basic fibroblast growth factor (bFGF) (Group-R) with the conventional method (Group-C) for patients with tympanic membrane perforation (TMP), both of whom underwent transcanal endoscopic ear surgery. METHODS: The study population of Group-R included 61 ears of 59 patients treated with RT-TMP in which TMP edges were disrupted mechanically and a gelatin sponge immersed in bFGF was inserted into the TMP. Fibrin glue was then dripped over the sponge. Group-C consisted of 13 patients who underwent conventional surgery before adopting the RT-TMP. Patients' characteristics and outcomes including TMP closure rates, and change in hearing level were evaluated three or more weeks after the surgery. RESULTS: The baseline characteristics including size of TMP were not significantly different between the two groups. Although Group-R had significantly shorter operating time than Group-C, the complete TMP closure rates were 69 % (9/13) and 85 % (52/61), respectively. Air-conduction hearing thresholds showed significant improvements, and analysis of variance showed that Group-R achieved significant interactions other than at 8 kHz, implying better improvement in cases with TMP closure. The air-bone gaps also improved at all frequencies in both groups. Specifically, at 4 kHz, there was a trend showing better improvement in Group-R. CONCLUSION: RT-TMP had a high TMP closure rate and good hearing improvement, with no significant differences compared with those of conventional surgery. This new therapy is simple and safe, and requires less operating time, and it could help improve the quality of life of patients with TMP.

Efficacy and safety of a self-expandable retainer in endoscopic ear surgery.

PURPOSE: During endoscopic ear surgery (EES), it is important to maintain a clear view of the endoscopic camera to achieve a clean field. In this study, a self-expandable external auditory canal (EAC) retainer was developed to enable a more efficient and safer EES. This study aimed to evaluate the retainer's efficacy and safety in EES. METHODS: Among adult patients scheduled for endoscopic tympanoplasty, 50 participants were recruited. They were assigned to either the retainer or control group in a 1:1 ratio. The anatomical characteristics, number of endoscopic cleanings during surgery, surgeon's satisfaction, and other factors were evaluated. RESULTS: No differences were observed in the surgical direction, EAC size measured on preoperative temporal bone computed tomography scans, location and size of tympanic membrane perforation, or bleeding degree between the two groups. When comparing the surgical time, including retainer insertion and removal, the time was similar between groups (retainer group, 35 min; control group, 33.2 min). The frequency of endoscopic cleaning per minute was statistically significantly lower in the retainer group than in the control group (0.18 times per minute, p = 0.048). No side effects, including sensory abnormalities or allergic reactions, were reported in any patient who used the retainer. CONCLUSION: A reduction in unnecessary endoscopic cleaning during EES was observed while using the self-expandable retainer, leading to increased surgeon satisfaction and efficiency. Furthermore, as a safe method without side effects, the retainer could be widely used to various indications for EES beyond tympanoplasty.

Exclusive endoscopic management of incus long process major defects: conventional incus interposition versus malleostapediopexy.

PURPOSE: The aim of the current study is to compare the surgical and audiometric results of conventional incus interposition (IP) versus malleostapediopexy (MS) in incus long process large defects. METHODS: A total of 71 patients (incus IP group n = 37, MS group n = 34) were enrolled in this study. All patients enrolled in the current study underwent ossiculoplasty via an exclusive endoscopic transcanal approach. Pre- and postoperative audiometric measurements and air-bone gap (ABG) values were compared, and if the postoperative ABG value was less than 20 dB, ossiculoplasty was considered successful. Graft success rates and complications were also compared. RESULTS: The average auditory gain was 14.7 ± 4.2 dB in the incus IP group and 18.3 ± 5.1 dB in the MS group. The auditory gain was significantly greater in the MS group relative to the incus IP group (p = 0.012). Ossiculoplasty success (postoperative ABG value < 20 dB) rate was 70.3% in the incus IP group patients and 88.2% in the MS group patients (p < 0.001). There was no significant difference in terms of graft success rate between groups (p > 0.05) and the overall graft uptake rate was 91.5% (65/71). CONCLUSION: Malleostapediopexy-bridging of malleus and stapes using bone cement-is an effective, reasonable, and more efficient technique in terms of auditory outcomes relative to the conventional incus interposition in endoscopic transcanal management of incus long process major defects.

Registration of preoperative temporal bone CT-scan to otoendoscopic video for augmented-reality based on convolutional neural networks.

PURPOSE: Patient-to-image registration is a preliminary step required in surgical navigation based on preoperative images. Human intervention and fiducial markers hamper this task as they are time-consuming and introduce potential errors. We aimed to develop a fully automatic 2D registration system for augmented reality in ear surgery. METHODS: CT-scans and corresponding oto-endoscopic videos were collected from 41 patients (58 ears) undergoing ear examination (vestibular schwannoma before surgery, profound hearing loss requiring cochlear implant, suspicion of perilymphatic fistula, contralateral ears in cases of unilateral chronic otitis media). Two to four images were selected from each case. For the training phase, data from patients (75% of the dataset) and 11 cadaveric specimens were used. Tympanic membranes and malleus handles were contoured on both video images and CT-scans by expert surgeons. The algorithm used a U-Net network for detecting the contours of the tympanic membrane and the malleus on both preoperative CT-scans and endoscopic video frames. Then, contours were processed and registered through an iterative closest point algorithm. Validation was performed on 4 cases and testing on 6 cases. Registration error was measured by overlaying both images and measuring the average and Hausdorff distances. RESULTS: The proposed registration method yielded a precision compatible with ear surgery with a 2D mean overlay error of 0.65 ± 0.60 mm for the incus and 0.48 ± 0.32 mm for the round window. The average Hausdorff distance for these 2 targets was 0.98 ± 0.60 mm and 0.78 ± 0.34 mm respectively. An outlier case with higher errors (2.3 mm and 1.5 mm average Hausdorff distance for incus and round window respectively) was observed in relation to a high discrepancy between the projection angle of the reconstructed CT-scan and the video image. The maximum duration for the overall process was 18 s. CONCLUSIONS: A fully automatic 2D registration method based on a convolutional neural network and applied to ear surgery was developed. The method did not rely on any external fiducial markers nor human intervention for landmark recognition. The method was fast and its precision was compatible with ear surgery.

Success and safety of endoscopic versus microscopic resection of temporal bone paraganglioma: a meta-analysis.

PURPOSE: Temporal bone paraganglioma (TBP) are the most common tumors of the middle ear. They pose a challenge in otologic surgery due to their extensive vascularity and intricate location within the middle ear. This meta-analysis aimed to compare the safety and efficacy of two surgical approaches, microscopic middle ear surgery (MMES) and endoscopic middle ear surgery (EMES), in the resection of TBP. METHODS: Eligible studies published after 1988 were identified through systematic searches of "PubMed", "Scopus" and "Google Scholar". Retrospective studies and randomized/non-randomized control trials reporting on surgical approaches for TBP with a minimum of five adult patients were included. RESULTS: A total of 595 records were initially identified. After removing 229 duplicates, 349 articles were excluded based upon article subject, title and abstract. Following the review of full texts, 13 articles were assessed for eligibility. The pooled analysis included a total of 529 ears, with a complication rate of 7.8% for EMES and 14.2% for MMES. Subgroup differences indicated no significant variation between the two methods (p = 0.2945). CONCLUSION: Both EMES and MMES demonstrated favorable surgical outcomes with low complication rates for TBP resection. These findings suggest that EMES is a safe and effective method for TBP resection and one that is comparable to MMES. Since the risk of bleeding is significant in these tumors, a third-hand technique, endoscopic bipolar cautery or laser-assisted hemostasis should be considered. Conversion to MMES is another option when visibility is critically affected by bleeding.

A study on the efficacy of combined surgery in advanced-stage congenital cholesteatoma with canal-wall-up surgery.

PURPOSE: This study aimed to compare the outcomes of patients with advanced congenital cholesteatoma who underwent microscopic or endoscope-combined Canal Wall Up Tympanomastoidectomy (CWUT) in our clinic and to determine the contribution of endoscope use in reducing recurrence/residual rates. METHODS: In this retrospective study, the data of individuals who underwent microscopic or combined endoscopic surgery between 2008 and 2022 in our clinic were scanned from the database. Demographic data, preoperative computed tomography (CT) findings, preoperative and postoperative hearing results, operation and intraoperative status of the ossicles, duration of surgery, postoperative follow-up period, recurrence and residual disease status during follow-up were investigated. RESULTS: The data of 37 pediatric cases operated in our clinic were included in the study. All of the included cases were Potsic Stage 4 patients who underwent CWUT. The mean age of the operated individuals was 8.7 years (5-12 years) and the mean follow-up period was 47.3 months (12-112 months). 19 cases were performed microscopically only, 2 recurrences and 5 residuals were detected. 18 cases were performed combined and 1 recurrence and 1 residual was found. CONCLUSION: In this study, it was determined that using an endoscope together with a microscope in congenital cholesteatoma cases, decreased the rate of recurrence and residual disease by protecting the external auditory canal in patients with advanced mastoid invasion.

Endoscopic ear surgery in the treatment of chronic otitis media with atelectasis.

PURPOSE: Atelectasis otitis media (AtOM) is a chronic condition where the tympanic membrane (TM) becomes retracted towards the middle ear and the ossicular chain. Surgical treatment for this condition could be indicated based on stage of atelectasis, patient's clinical condition and hearing loss. Over the years, AtOM has been treated with various types of tympanoplasty under microscopic view. The aim of this study is to present the results of endoscopic ear surgery in AtOM. METHODS: Forty-five patients who underwent endoscopic trans-canal tympanoplasty were included in the study. Preoperative features, intraoperative findings and postoperative outcomes were collected. RESULTS: Preoperatively, none of the study's patients were classified with a Sadè Grade I, whereas grades II, III and IV were 3 (6.6%), 23 (32.1%) and 19 (67.8%) respectively. The 3 patients with Sadè grade II showed a conductive hearing loss higher than 20 dB and a continuous ear fullness, therefore they were surgically treated. The postoperative graft success rate was estimated at 95.5%. During follow-up, 2 patients showed a TM perforation (at 6 and 12 months after surgery) whereas 1 patient experienced a recurrence of atelectasis in the TM (16 months after surgery). The overall success rate at the final follow-up was calculated at 88.8%. The average preoperative air-conduction threshold was 51.1 ± 21.5, which reduced to 34.6 ± 22.1 (p = 0.04) at follow-up. The preoperative air-bone gap decreased from 28 ± 7.2 to 11.8 ± 10 (p = 0.002) after surgery. CONCLUSION: Atelectasis otitis media might be suitable for exclusive endoscopic surgical treatment, as it appears to exhibit a low recurrence rate and promising audiological outcomes.

Applicability of ChOLE staging to preoperative HRCT temporal bone in chronic otitis media with cholesteatoma.

PURPOSE: Chronic otitis media with cholesteatoma is a frequent disease entity in otology, requiring surgery in overwhelming majority of cases. Despite the huge burden there is no established grading system available to assess the severity and extent of disease preoperatively until date. Aim of our study is to assess the applicability of ChOLE staging to preoperative HRCT temporal bone in Chronic otitis media with cholesteatoma. METHODOLOGY: Patients clinically diagnosed as COM with cholesteatoma, who underwent preoperative HRCT temporal bone imaging and mastoid exploration at our tertiary care centre were included. Preoperative radiology was assessed and a radiological ChOLE (r-ChOLE) was given by radiologist. This was then compared with the postop ChOLE. RESULTS: 21 patients were included in the study. Data was linear and normally distributed (Shapiro wilk test). Pearson's product-moment correlation used to see relationship between radiological and postop Total score showed strong statistically significant positive correlation with correlation coefficient (r) of 0.977. Paired t test showed p value was 0.329 (p > 0.05) suggesting no significant difference between radiological and postop Total scores. Cohen kappa test of agreement was applied. It revealed an overall strong agreement (p < 0.001). CONCLUSION: ChOLE staging may be extended to preoperative HRCT of temporal bone in COM with cholesteatoma (rCHOLE). A preoperative radiological staging will help in better prioritizing, planning and execution of tympanomastoid surgeries.

Exclusive endoscopic tympanoplasty efficacy in the treatment of cholesteatoma without mastoid involvement.

PURPOSE: The purpose of this study is to determine the recurrence rate of cholesteatoma in patients who have undergone exclusive endoscopic tympanoplasty at our tertiary referral institution. A secondary objective is to analyze different clinical aspects that could be considered risk factors for recurrence to establish if it is possible to determine when a second-look procedure is indicated instead of a clinical follow-up. METHODS: A retrospective study was performed on patients who had undergone exclusive endoscopic tympanoplasty for cholesteatoma in the last eight years and who were followed up for at least one year. The efficacy of the treatment performed only with the exclusive endoscopic technique was analyzed. Then, the anamnestic and intraoperative data were studied to identify possible factors that could increase the risk of recurrence. RESULTS: The recurrence rate (14.5%) in patients (164) who underwent primary surgery with the exclusive endoscopic technique between January 2014 and January 2022 was similar to that in patients who underwent the microscopic technique with mastoidectomy in literature. In addition, we analyzed several clinical factors such as age, ossicular chain erosion, extension and localization of the cholesteatoma finding that only the last one could potentially be a risk factor for recurrence in this selected population. CONCLUSION: Exclusive endoscopic tympanoplasty has been shown to be effective in removing cholesteatoma in patients without evidence of mastoid involvement, with recurrence rates comparable to traditional microscopic technique and a minimally invasive approach, even considering the patient's age, ossicular chain erosion and extension of the disease.

A new 3D-printed temporal bone: 'the SAPIENS'-specific anatomical printed-3D-model in education and new surgical simulations.

PURPOSE: Otology and neuro-otology surgeries pose significant challenges due to the intricate and variable anatomy of the temporal bone (TB), requiring extensive training. In the last years 3D-printed temporal bone models for otological dissection are becoming increasingly popular. In this study, we presented a new 3D-printed temporal bone model named 'SAPIENS', tailored for educational and surgical simulation purposes. METHODS: The 'SAPIENS' model was a collaborative effort involving a multidisciplinary team, including radiologists, software engineers, ENT specialists, and 3D-printing experts. The development process spanned from June 2022 to October 2023 at the Department of Sense Organs, Sapienza University of Rome. Acquisition of human temporal bone images; temporal bone rendering; 3D-printing; post-printing phase; 3D-printed temporal bone model dissection and validation. RESULTS: The 'SAPIENS' 3D-printed temporal bone model demonstrated a high level of anatomical accuracy, resembling the human temporal bone in both middle and inner ear anatomy. The questionnaire-based assessment by five experienced ENT surgeons yielded an average total score of 49.4 ± 1.8 out of 61, indicating a model highly similar to the human TB for both anatomy and dissection. Specific areas of excellence included external contour, sigmoid sinus contour, cortical mastoidectomy simulation, and its utility as a surgical practice simulator. CONCLUSION: We have designed and developed a 3D model of the temporal bone that closely resembles the human temporal bone. This model enables the surgical dissection of the middle ear and mastoid with an excellent degree of similarity to the dissection performed on cadaveric temporal bones.

Blue laser for the exclusive endoscopic transcanal approach to middle ear paraganglioma.

BACKGROUND: The management of glomus tympanicum tumours can be challenging. Blue laser coagulation may improve bleeding control thus facilitating an endoscopic transcanal excision. The objective of this presentation is to illustrate the authors' experience using this novel tool. METHODS: Case report of a patient that underwent exclusive endoscopic transcanal blue laser surgery of a class A2 glomus tympanicum tumour in a tertiary referral center. CONCLUSION: The present study provides evidence of the safety and efficacy of endoscopic blue laser surgery, for the minimally invasive treatment of early-stage glomus tympanicum tumours.

To detach or not to detach the umbo in type I tympanoplasty: functional results.

PURPOSE: To compare the audiological outcomes, tympanic membrane (TM) healing rates and complication rates in patients undergoing endoscopic underlay and over-under tympanoplasty type I (TTI). METHODS: The study includes 95 patients who underwent endoscopic TTI in the period between 2018 and 2023: 56% of the patients had the underlay technique and 41% had the over-under technique. Data regarding pre- and postoperative hearing, perforation characteristics, surgical procedures, graft types and complications were retrospectively analyzed. Audiometrical assessment included air conduction (AC) and bone conduction (BC) pure tone averages (PTA) and air-bone gap (ABG), pre- and postoperatively. RESULTS: Both underlay and over-under techniques significant improved AC PTA, with a mean ABG improvements of 5.9 dB and 7.2 dB, respectively. There was no significant difference in BC PTA between pre- and post-operative, indicating no inner ear damage in both techniques. The over-under technique showed a significantly higher TM closure rate (94.4%) compared to the underlay technique (80.6%). Complications were rare, with only one case of TM lateralization requiring revision surgery. CONCLUSIONS: Endoscopic TTI is an effective treatment in improving auditory function in chronic middle ear diseases. In our cohort, the detachment of the umbo does not negatively influence the postoperative hearing results and does not increase rate of complications. Moreover, the over-under technique demonstrates superior TM closure rates, making it a valuable option for specific cases. However, future prospective studies with larger sample sizes and longer term follow-up are needed to validate these findings and provide more comprehensive insights.

Conventional one-handed compared to two-handed endoscopic ear surgery using an endoscope holder: a single center study.

INTRODUCTION: One-handedness is a challenge in conventional endoscopic ear surgery (EES). We present results on the first-ever application of the passive endoscope holder 'Endofix exo' (Co. AKTORmed GmbH, Neutraubling, Germany) in EES, which enables two-handed surgery. METHODS: This two-sided study compares cut-suture time, operating time, postoperative complications, graft take rates, hearing results and quality of life in patients who underwent first stage tympanoplasty due to tympanic membrane perforation with intact ossicular chain conditions. 25 patients received classic EES (EES-, mean age: 28 ± 21 years) and 15 received EES with the passive holder (EES+, mean age: 48 ± 21 years). RESULTS: Mean operating times (EES-: 96 ± 38 (SD) min; EES+: 107 ± 33 min), cut-suture times (EES-: 68 ± 30 min; EES+: 73 ± 31 min), complications, graft take rates and hearing results (preoperative air bone gap (ABG) (PTA4): 15 dB ± SD 8 dB (EES-); 16 dB ± SD 8 dB (EES+); postoperative ABG (PTA4): 11.25dB ± SD 11.3dB (EES-); 14 dB ± SD 10 dB (EES+)) did not differ significantly (p > 0.05) between the two groups. Postoperative hearing results and quality of life tended to improve in both groups (p > 0.05). DISCUSSION: The passive endoscope holder has been successfully applied during the course of the study. However, modifications of the endoscope holder and further studies are recommended focusing on positioning of grafts and prostheses to obtain conclusive results regarding the superiority of two-handed EES over one-handed conventional EES.

The endoscopic transcanal approach to the internal auditory canal: an anatomic study.

PURPOSE: The internal auditory canal (IAC) plays a key role in lateral skull base surgery. Although several approaches to the IAC have been proposed, endoscope-assisted transcanal corridors to the IAC have rarely been studied. We sought to provide a step-by-step description of the transcanal transpromontorial approach to the IAC and analyze anatomic relationships that might enhance predictability and safety of this approach. METHODS: Ten cadaveric specimens were dissected and the extended transcanal transpromontorial approach to the IAC was established. Various morphometric measurements and anatomic landmarks were reviewed and analyzed. RESULTS: The proposed technique proved feasible and safe in all specimens. There was no inadvertent injury to the jugular bulb or internal carotid artery. The chorda tympani, a key landmark for the mastoid segment of the facial nerve, was identified in all dissections. The spherical recess of the vestibule and middle turn of cochlea are important landmarks for identification of the labyrinthine segment of the facial nerve. Identification of all boundaries of the working area is also essential for safe access. Among various morphometric measurements, the modiolus-IAC angle (≈ 150°) proved particularly consistent; given its ease of use and low variability, we believe it could serve as a landmark for identification and subsequent dissection of the IAC. CONCLUSIONS: The extended transcanal transpromontorial approach to the IAC is feasible and safe. Relying on anatomic landmarks to ensure preservation of the involved neurovascular structures is essential for a successful approach. The modiolus-IAC angle is a consistent, reproducible landmark for IAC identification and dissection.

Validity of endoscopic ossiculoplasty immediately after its introduction for ossicular chain disruption.

BACKGROUND: Transcanal endoscopic ear surgery (TEES) reportedly requires a long learning curve and may be associated with more complications and longer operative times than microscopic ear surgery (MES). In this study, we aimed to examine the usefulness and validity of TEES for ossicular chain disruption in the early stages of its introduction in our institution. METHODS: TEES was performed on 11 ears (10 with congenital ossicular chain discontinuity and 1 with traumatic ossicular chain dislocation), and MES was performed with a retroauricular incision on 18 ears (6 with congenital ossicular chain discontinuity and 12 with traumatic ossicular chain dislocation) in a tertiary referral center. Postoperative hearing results, operative times, and postoperative hospital length of stay were retrospectively reviewed. The Mann-Whitney U test and Fisher's exact test was performed to compare variables between the TEES and MES groups. Pre- and postoperative air- and bone-conduction thresholds and the air-bone gap of each group were compared using the Wilcoxon signed-rank test. The Mann-Whitney U test and Wilcoxon signed-rank was performed to compare the pre- and postoperative air-bone gaps between the diagnoses. RESULTS: No significant differences in the postoperative air-conduction thresholds, bone-conduction thresholds, air-bone gaps, or incidence of air-bone gap ≤ 20 dB were observed between the TEES and MES groups. The air-conduction thresholds and air-bone gaps of the TEES group significantly improved postoperatively. The air-conduction thresholds and air-bone gaps of the MES group also significantly improved postoperatively. No significant difference was observed in the operative times between the groups (TEES group: median, 80 min; MES group: median, 85.5 min). The TEES group had a significantly shorter postoperative hospital stay (median, 2 days) than the MES group (median, 7.5 days). CONCLUSIONS: TEES was considered appropriate for the treatment of ossicular chain disruption, even immediately after its introduction at our institution. For expert microscopic ear surgeons, ossicular chain disruption may be considered a suitable indication for the introduction of TEES.