Endoscopic Transclival Approach Research Articles

Augmented Reality, Surgical Navigation, and 3D Printing for Transcanal Endoscopic Approach to the Petrous Apex.

Otolaryngologists increasingly use patient-specific 3-dimensional (3D)–printed anatomic physical models for preoperative planning. However, few reports describe concomitant use with virtual models. Herein, we aim to (1) use a 3D-printed patient-specific physical model with lateral skull base navigation for preoperative planning, (2) review anatomy virtually via augmented reality (AR), and (3) compare physical and virtual models to intraoperative findings in a challenging case of a symptomatic petrous apex cyst. Computed tomography (CT) imaging was manually segmented to generate 3D models. AR facilitated virtual surgical planning. Navigation was then coupled to 3D-printed anatomy to simulate surgery using an endoscopic approach. Intraoperative findings were comparable to simulation. Virtual and physical models adequately addressed details of endoscopic surgery, including avoidance of critical structures. Complex lateral skull base cases may be optimized by surgical planning via 3D-printed simulation with navigation. Future studies will address whether simulation can improve patient outcomes.

Transcanal endoscopic infracochlear vestibular neurectomy: A pilot cadaveric study

PurposeEffective operative approaches for the treatment of refractory vertigo in Meniere's disease are invasive. Vestibular neurectomy can preserve hearing and has been shown to be effective; however, current approaches require an extensive craniotomy. Transcanal endoscopic approaches to the internal auditory canal (IAC) with cochlear preservation have been recently described and may offer a minimally invasive approach to selectively sectioning the distal vestibular nerves while preserving residual hearing. Materials and methodsThree cadaveric human heads were imaged using high resolution computed tomography (CT). Anatomic analysis of preoperative CT scans showed adequate diameters (>3 mm) of the infracochlear surgical corridor for access to the IAC. A transcanal endoscopic approach was attempted to section the vestibular nerve. Post-operative CT scans were assessed to define the operative tract, determine cochlear preservation and assess cochlear and facial nerve preservation. ResultsTranscanal endoscopic approach was successfully performed (n = 3) using 3 mm-diameter, 14 cm-length 0°, 30°, and 45° endoscopes and microsurgical drills. In all cases the tympanomeatal flap and ossicular chain remained intact. Internal auditory canalotomy was performed using angled instruments and confirmed in real time via lateral skull base navigation. The vestibular nerves were readily identified and sectioned with preservation of the facial and cochlear nerves. Post-procedure CT showed no violation of the cochlea. ConclusionA transcanal, infracochlear approach to the IAC may permit a minimally invasive approach to distal vestibular neurectomy in cadavers with appropriate anatomy.

Novel Surgical and Radiologic Classification of the Subtympanic Sinus: Implications for Endoscopic Ear Surgery.

Objective The aim of this study is to describe the endoscopic anatomy of the subtympanic sinus (STS), establish a classification according to its extension regarding the level of the facial nerve (FN), and assess the feasibility of the transcanal endoscopic approach to the STS. Study Design Experimental anatomic research. Setting Temporal bone laboratory. Methods We performed endoscopic dissection of 34 human whole head and ear block specimens. Of those, 29 underwent high-resolution computed tomography. The STS was classified according to its extension regarding the level of the FN: type A, no extension medial to the FN; type B, extension to the medial limit of the FN; type C, extension of the sinus medially and posteriorly from the FN into the mastoid cavity. Results The majority of cases (n = 21, 72%) showed a shallow type A STS. We observed a deep type B configuration in 6 cases (21%) and a type C in 2 cases (7%). The STS was completely exposable with a 0° endoscope in 44% of the specimens. Using a 45° endoscope, we gained complete insight in 79%. However, in 21% of the cases, the posteromedial extension of the STS was too deep to be completely explored by an endoscopic transcanal approach. Conclusion The majority of the STS is shallow and does not extend medially from the FN. This morphologic variant allows complete transcanal endoscopic visualization. In more excavated STS, a complete endoscopic exploration is not achievable, and a retrofacial approach may be adopted to completely access the STS.

Transcanal Endoscopic Ear Surgery for Congenital Cholesteatoma.

Objectives As endoscopic instrumentation, techniques and knowledges have significantly improved recently, endoscopic ear surgery has become increasingly popular. Transcanal endoscopic ear surgery (TEES) can provide better visualization of hidden areas in the middle ear cavity during congenital cholesteatoma removal. We aimed to describe outcomes for TEES for congenital cholesteatoma in a pediatric population.Methods Twenty-five children (age, 17 months to 9 years) with congenital cholesteatoma confined to the middle ear underwent TEES by an experienced surgeon; 13 children had been classified as Potsic stage I, seven as stage II, and five as stage III. The mean follow-up period was 24 months. Recurrence of congenital cholesteatoma and surgical complication was observed.Results Congenital cholesteatoma can be removed successfully via transcanal endoscopic approach in all patients, and no surgical complications occurred; only one patient with a stage II cholesteatoma showed recurrence during the follow-up visit, and the patient underwent revision surgery. The other patients underwent one-stage operations and showed no cholesteatoma recurrence at their last visits. Two patients underwent second-stage ossicular reconstruction.Conclusion Although the follow-up period and number of patients were limited, pediatric congenital cholesteatoma limited to the middle ear cavity could be safely and effectively removed using TEES.

Endoscopic push-through technique compared to microscopic underlay myringoplasty in anterior tympanic membrane perforations.

Microscopic myringoplasty is the most frequently performed procedure for repairing tympanic membrane perforations. The endoscopic transcanal approach bypasses the narrow ear canal segment and provides a wider view. An open-label randomised clinical trial was conducted on 56 patients with small anterior tympanic membrane perforations. Perforations were repaired with an endoscopic push-through technique (n = 28) or a microscopic underlay technique (n = 28). Follow up was conducted using endoscopic examination and pure tone audiometry three months' post-operatively. Graft success rate was 92.9 per cent in the endoscopic group versus 85.7 per cent in the microscopic group. The corresponding pre-operative mean air-bone gaps were 17.4 dB and 18.5 dB, improving to 6.1 dB and 9.3 dB post-operatively (p > 0.05). Mean air-bone gap closure was 11.4 dB in the endoscopic group and 9.2 dB in the microscopic group (p > 0.05). Mean operative time and estimated blood loss were 37.0 minutes and 29 ml in the endoscopic group, versus 107 minutes and 153 ml in the microscopic group (both p < 0.05). The endoscopic push-through technique for anterior tympanic membrane perforations is as effective as microscopic underlay myringoplasty; furthermore, it is less invasive and takes less operative time.

Endoscopic transcanal myringoplasty:Is learning curve a myth?

ObjectiveTo investigate the feasibility of transcanal endoscopic myringoplasty in the hand of young beginner surgeons who had just completed the residency programme. MethodsIn a three year period (August 2012 to August 2015), 44 ears in 42 patients were operated upon by a beginner surgeon through the transcanal endoscopic approach in a subdistrict level hospital located in the north western ranges of the Himalayan region. ResultsOf the 42 patient, 19 were male and 23 female. The mean age was 26.23 years (range: 15–47 years). In 40 ears, complete perforation closure was achieved at six months (success rate: 90.9%). The mean air conduction PTA preoperatively was 40.84 dB HL and improved to 28.06 dB HL postoperatively (p < .001). The mean AB gap preoperatively was 22.40 dB, which improved to 9.1 dB postoperatively (p < .001). ConclusionEndoscopic transcanal myringoplasty is safe and reliable even in young beginners' hands. Surgeons can consider endoscopic approach early in their careers without the fear of learning curve. The cost of endoscopic equipment is about one tenth as compared to open approach under a operating microscope, and an added advantage.

The Impact of the Transcanal Endoscopic Approach and Mastoid Preservation on Recurrence of Primary Acquired Attic Cholesteatoma.

We aim to investigate the factors associated with recurrent disease following surgery for primary acquired attic cholesteatoma. We hypothesize that minimal invasive, mucosal sparing operation techniques have beneficial effects on the outcome in terms of recurrence. Retrospective study. Tertiary referral center. A total of 110 patients presenting with primary acquired attic cholesteatoma were enrolled in the study. Patients undergoing revision surgery or a canal wall down procedure, as well as patients with residual disease were excluded from the study. During follow-up recurrence was assessed and classified into normal, self-cleaning retraction pockets, or recurrent cholesteatoma requiring revision surgery. We observed during follow-up statistically significant decrease (p = 0.036) in the occurrence of retraction pockets and recurrence in patients operated by the transcanal endoscopic approach (n = 55, 11% re-retraction, 9% recurrence) compared with those who underwent a canal wall up procedure (n = 55, 16% re-retraction, 22% recurrence). However, the multivariate model did not demonstrate statistically significant predictors regarding the outcome. Moreover, the preservation or direct reconstruction of the ossicular chain had a beneficial effect on the outcome. We observed 11% re-retraction and 9% recurrence in cases with preserved or reconstructed ossicular chain versus 18% re-retraction and 24% recurrence (p = 0.011) in cases of nonpreserved or non-reconstructed ossicular chain. A score was established according to the intraoperative mucosal damage and correlated to the occurrence of recurrence (p = 0.02). The risk of recurrence increased by 23.6% (95% confidence interval: 3.22-48.1) with each additional mucosal damage site. Transcanal endoscopic approaches that preserve the mastoid may play an important role in preventing recurrence and underscores the importance of the mucosa and mastoid air cells on middle ear homeostasis.

Facial sinus endoscopic evaluation, radiologic assessment, and classification.

To describe facial sinus anatomy from an endoscopic perspective and present a radiologic classification. Facial sinus was studied by endoscopy and high-resolution computed tomography (HRCT) scan in 39 temporal bones that underwent exclusive transcanal endoscopic approach. A radiomorphologic classification based on the relationship between the facial sinus and the mastoid portion of the facial nerve is created as follows. In type A facial sinus, the pneumatization of the facial sinus did not extend medially or posteriorly to the mastoid portion of the facial nerve. In type B facial sinus, the pneumatization extended posteriorly to the mastoid portion of the facial nerve. In type C facial sinus, the pneumatization extended posteriorly and medially to the mastoid portion of the facial nerve. In all the specimens that underwent HRCT (n = 31), facial sinus could be identified, and its depth classified, in relation to the facial nerve. In this group, 58% type A, 29% type B, and 13% type C facial sinuses were identified. In all the specimens (n = 39), the facial sinus could be assessed by means of an exclusive endoscopic transcanal approach, and anatomical variants of the chordiculus, previously known as chordal ridge, could be described: ridge (39%), bridge (18%), incomplete (15%), and absent (28%). Endoscopic exploration of the retrotympanum guarantees a very good exposure of the facial sinus, allowing detailed anatomic descriptions of its conformation and relationships with other structures. Improvement in our knowledge of its anatomy might decrease the possibility of residual disease during cholesteatoma surgery. Angled endoscopes (e.g. 45 °, 70 °) can guarantee a better view of the facial sinus. NA. Laryngoscope, 128:2397-2402, 2018.

Transnasal Endoscopic and Lateral Approaches to the Clivus: A Quantitative Anatomic Study.

Transnasal endoscopic approaches to the clivus have been established recently. Comparative analyses with classic lateral approaches are limited. In this study, we compared transnasal endoscopic and lateral approaches to the clivus, quantifying the exposure and working volume of each approach in the anatomy laboratory. High-resolution computed tomography scans were performed on 5 injected specimens (10 sides). In each specimen, transnasal endoscopic approaches (i.e., paraseptal, transrostral, extended transrostral, transethmoidal, and extended transclival without and with intradural hypophysiopexy) and lateral approaches (i.e., retrosigmoid, far-lateral, presigmoid retrolabyrinthine and translabyrinthine) to the clivus were performed. An optic neuronavigation system and dedicated software (ApproachViewer; Guided Therapeutics Program, University Health Network, Toronto, Ontario, Canada) were used to quantify the working volume and exposed clival area of each approach. Statistical evaluation was performed with the Kruskal-Wallis test and Steel-Dwass-Critchlow-Fligner post hoc test. Endoscopic transnasal transclival approaches showed higher working volume and larger clival exposure compared with lateral approaches. Incremental volumetric values were evident for transnasal approaches; presigmoid approaches provided less working volume than retrosigmoid approaches. A transnasal transclival approach with hypophysiopexy provided significant exposure of the upper clivus (84.4%). The transrostral approach was the first transnasal approach providing satisfactory access to the midclivus (66%); retrosigmoid and far-lateral approaches provided exposure of approximately one half of the midclivus. The lower clivus was optimally exposed with endoscopic transclival approaches (83%), whereas access to this region was limited with lateral approaches. This quantitative anatomic study shows that endoscopic transnasal approaches to the clivus provide a larger working volume and wider exposure of the clivus compared with lateral approaches.

Endoscopic Transcanal Approach to Lateral Skull Base Lesions

Endoscopic Transcanal Approach to Lateral Skull Base Lesions

Discovering Middle Ear Anatomy by Transcanal Endoscopic Ear Surgery: A Dissection Manual.

The middle ear is located in the center of the temporal bone and bears a highly complex anatomy. The recently introduced exclusively endoscopic transcanal approach to the middle ear is a minimally invasive technique sparing the bone and mucosa of the mastoid bone, since the middle ear is accessed through the external auditory canal. This emerging method has several advantages over the traditional (microscopic) approaches to the middle ear such as the panoramic wide-angle views of the anatomy, the possibility to approach and magnify tiny structures, and the possibility of looking around the corner using angled endoscopes.The cadaveric dissection method presented here consists of an overview on the technical requirements and a precise description of a step-by-step protocol to discover the anatomy of the middle ear. Each step and anatomical structure is carefully described in order to provide a comprehensive guide to endoscopic ear anatomy. In our opinion, this is particularly important to any novice in endoscopic ear surgery as it provides thorough anatomical knowledge and may improve surgical skills.

Discovering Middle Ear Anatomy by Transcanal Endoscopic Ear Surgery: A Dissection Manual

The middle ear is located in the center of the temporal bone and bears a highly complex anatomy. The recently introduced exclusively endoscopic transcanal approach to the middle ear is a minimally invasive technique sparing the bone and mucosa of the mastoid bone, since the middle ear is accessed through the external auditory canal. This emerging method has several advantages over the traditional (microscopic) approaches to the middle ear such as the panoramic wide-angle views of the anatomy, the possibility to approach and magnify tiny structures, and the possibility of looking around the corner using angled endoscopes. The cadaveric dissection method presented here consists of an overview on the technical requirements and a precise description of a step-by-step protocol to discover the anatomy of the middle ear. Each step and anatomical structure is carefully described in order to provide a comprehensive guide to endoscopic ear anatomy. In our opinion, this is particularly important to any novice in endoscopic ear surgery as it provides thorough anatomical knowledge and may improve surgical skills.

Endoscopic Anatomy of the Tensor Fold and Anterior Attic.

Objectives The objectives of the study were to (1) study the anatomical variations of the tensor fold and its anatomic relation with transverse crest, supratubal recess, and anterior epitympanic space and (2) explore the most appropriate endoscopic surgical approach to each type of the tensor fold variants. Study Design Cadaver dissection study. Setting Temporal bone dissection laboratory. Subjects and Methods Twenty-eight human temporal bones (26 preserved and 2 fresh) were dissected through an endoscopic transcanal approach between September 2016 and June 2017. The anatomical variations of the tensor fold, transverse crest, supratubal recess, and anterior epitympanic space were studied before and after removing ossicles. Results Three different tensor fold orientations were observed: vertical (type A, 11/28, 39.3%) with attachment to the transverse crest, oblique (type B, 13/28, 46.4%) with attachment to the anterior tegmen tympani, and horizontal (type C, 4/28, 14.3%) with attachment to the tensor tympani canal. The tensor fold was a complete membrane in 20 of 28 (71.4%) specimens, preventing direct ventilation between the supratubal recess and anterior epitympanic space. We identified 3 surgical endoscopic approaches, which allowed visualization of the tensor fold without removing the ossicles. Conclusions The orientation of the tensor fold is the determining structure that dictates the conformation and limits of the epitympanic space. We propose a classification of the tensor fold based on 3 anatomical variants. We also describe 3 different minimally invasive endoscopic approaches to identify the orientation of the tensor fold while maintaining ossicular chain continuity.

Total Endoscopic Approach in Glomus Tympanicum Surgery

Glomus tympanicum (GT) is a benign primary tumor of the middle ear. The evolution of endoscopic ear surgery has allowed for an alternative approach to managing this vascular tumor. The purpose of this study was to evaluate an endoscopic approach in GT surgery, and also to investigate its applicability and feasibility. Prospectively, 13 class I and II patients, according to the Glasscock-Jackson glomus classification, were candidates for management via a transcanal endoscopic approach. Patients were categorized into three groups according to the location of the tumor in the middle ear. Group A consisted of patients with tumors located anteriorly while occupying the Eustachian tube. Group B were patients with tumors located on the promontory with entirely visible tumor borders. Patients in Group C had tumors that occupied the entire middle ear. Under specially designed flap elevation and hemostasis, the tumors were completely removed using an endoscopic technique. Based on the classification criteria, three patients fell into Group A (30%), six into Group B (46%), and three into Group C (23%). The principal chief complaint was pulsatile tinnitus that disappeared after surgery in most cases. Hearing status was mostly mixed hearing loss. No change was detected in bone conduction after surgery, but air conduction was improved in nine cases. No major complication or recurrence was observed over 30 months of follow up. Improved exposure and access in the endoscopic transcanal approach to GT leads to safe, rapid, and reliable tumor removal, as well as allowing comfortable surgery for both the surgeon and most patients.

Bilateral congenital cholesteatoma: Surgical treatment and considerations

ObjectivesTo describe a multicenter study regarding surgical management of bilateral congenital cholesteatoma (BCC) and underline the importance of endoscopes in the management of this condition. In BCC, hearing preservation is more crucial than in unilateral cases. The endoscopic approach allows complete removal of cholesteatoma via a minimally invasive technique offering low residual disease rates while preserving the normal physiology of the middle ear and possibly the ossicular chain. Study designRetrospective chart and surgical video review of patients with BCC who underwent surgery at Otolaryngology Department of Modena and Verona University Hospitals and the Hospital for Sick Children, Toronto. MethodsFrom 2002 to November 2016, six patients were identified with bilateral congenital cholesteatoma and included in this study. Pre-operative assessments, surgical treatments and outcomes were collected and described. ResultsThe median age at presentation was 4 years (range 2–7 years). A microscopic post auricular tympanoplasty was performed in two ears, four underwent a canal wall up mastoidectomy procedure and in the other six a transcanal endoscopic approach (TEA) was used. No intra- or post-operative complications were observed in any patients. The mean follow up period was 54.5 months. ConclusionsWhen both ears are involved with congenital cholesteatoma, it is particularly important to use a minimally invasive technique that preserves normal ossicular and mastoid structure and function whenever possible. In many cases this can be achieved with TEA, even in young children. In addition the endoscope allows good surgical control of cholesteatoma removal from hidden recesses.

Endoscopic transcanal approach to the middle ear for management of pediatric cholesteatoma.

To describe outcomes for endoscopic ear surgery (EES) for pediatric cholesteatoma at a tertiary pediatric hospital. Retrospective case series of 65 pediatric cholesteatoma cases in 38 ears. Subgrouping based on cholesteatoma type and EES type. Surgical findings, outcomes, and demographic data were evaluated. Endoscopes were used in 65 pediatric cholesteatoma cases in 38 primary ears (34 patients), followed for an average of 2.6 years (9 months to 4.6 years). The endoscope was used as the primary visualization tool in 31 (81.6%) ears (EES 2 or 3), and as an adjunct to the microscope in seven ears (EES 1). Twenty-two (57.9%) ears and 35 (53.4%) cases were transcanal endoscopic ear surgery (EES 3 or TEES). Overall, there was recurrence in five (13.2%) ears and residual in four (10.5%) ears. Cholesteatoma was acquired in 27 ears, with average age 10.9 years; and congenital in 11 ears, with average age 3.8 years. Surgical time was longer for acquired cases (226 vs. 154 minutes). Hearing outcomes were comparable for both cholesteatoma types. Residual disease was seen in three (11.1%) acquired ears and one (9.1%) congenital ear. Overall, the lowest rates of recurrent and residual disease were seen in EES 3 cases, and relatively low rates in EES 2 and 3 ears, including four (12.9%) recurrences and two (6.5%) ears with residual disease. The endoscopes are a viable tool for resection of pediatric cholesteatoma and provide excellent visualization of the middle ear and associated recesses. 4. Laryngoscope, 127:2653-2658, 2017.

Quantitative imaging analysis of transcanal endoscopic Infracochlear approach to the internal auditory canal

PurposeA transcanal endoscopic infracochlear surgical approach to the internal auditory canal (IAC) in a human temporal bone model has previously been described. However, the proportion of patients with favorable anatomy for this novel surgical technique remains unknown. Herein, we perform a quantitative analysis of the transcanal endoscopic infracochlear corridor to the IAC based on computed tomography. Materials and methodsHigh resolution computed tomography scans of adult temporal bones were measured to determine the accessibility of the IAC when using an endoscopic transcanal, cochlear-sparing surgical corridor. ResultsThis approach to the IAC was feasible in 92% (35 of 38) specimens based on a minimum distance of 3mm between the basilar turn of the cochlear and the great vessels (jugular bulb and carotid artery). ConclusionsInfracochlear access to the IAC is feasible in the majority of adult temporal bones and has implications for future hearing preservation drug delivery approaches to the IAC.

Transcanal endoscopic approach to lesions of the suprageniculate ganglion fossa

ObjectiveThe aim of this paper would be to describe the first case series of exclusive transcanal endoscopic approach to treat lesions with limited extension at the suprageniculate fossa. This endoscopic approach allowed a complete removal of suprageniculate disesases with low complication rates using a minimally invasive surgical route. MethodsThis is a retrospective chart analysis and a surgery video recording review of these patients were performed in August 2015. From November 2011 to November 2015, 29 patients were submitted to an endoscopic transcanal lateral skull base surgery. From those 29 subjects, in 6 patients an exclusive endoscopic transcanal suprageniculate approach was performed to remove lesions located into the geniculate fossa. Surgical indications, pre-operative assessment, results were collected and the surgical technique were described. ResultsThe final study group was composed of 6 patients. 3 male and 3 female; median age is 25.3 years old. In all 6 subjects it was possible to remove the lesions using an exclusive endoscopic transcanal suprageniculate approach. No intraoperaoperative complications were observed in any patients. The mean follow up period was 15.16 months. ConclusionExclusive endoscopic transcanal suprageniculate approach is definitely a minimally invasive technique and should be consider an optimal solution to treat lesions located in the suprageniculate fossa in some patients. We introduce a minimally invasive approach to the geniculate ganglion region in order to allow complete removal of suprageniculate disesases with low complication rates using a minimally invasive surgical route.

Endoscopic Management of Middle Ear Paragangliomas: A Case Series.

To investigate the efficacy and safety of endoscopic middle ear paraganglioma (glomus tympanicum) resection. Case series with chart review. Multi-institutional tertiary university medical centers. Adult patients with middle ear paragangliomas treated via a transcanal endoscopic approach from 1/2012 to 11/2015. All tumors were initially approached via a transcanal endoscopic technique. An operating microscope was used only if the tumor could not be adequately visualized or resected with endoscopic techniques alone. The main outcome was completeness of tumor resection via the endoscopic technique. Secondary measures were resolution of pulsatile tinnitus, audiometric outcomes, surgical duration, and surgical complications. Endoscopic resection was attempted on 14 middle ear paragangliomas. Thirteen patients (93%) were women with a mean age of 61.6 years. The mean tumor size was 6.2 mm (SD, 3.3). Eleven cases (79%) had complete resection via an exclusive endoscopic approach. The mean surgical duration was 108.1 minutes (SD, 55.6). One case required use of an operating microscope via a transcanal route and two cases required postauricular incisions with mastoidectomy. There were no significant postoperative complications. Two patients (14%) had tympanic membrane perforations repaired intraoperatively without residual perforation on follow-up. All patients had normal postoperative facial nerve function. Pulsatile tinnitus resolved after surgery in all 13 patients who presented with this symptom preoperatively. The mean pure-tone average improved by 5.9 dB (SD, 4.6) after surgery. Endoscopic management of middle ear paraganglioma is safe, feasible, and effective.

Endoscopic middle ear exploration in pediatric patients with conductive hearing loss

ObjectiveTo describe our indications, findings, and outcomes for transcanal endoscopic middle ear exploration in pediatric patients with conductive hearing loss of unknown etiology, without effusions. MethodsProspective case series for all pediatric patients undergoing totally endoscopic transcanal middle ear exploration between April 2012 and October 2015 at a pediatric tertiary care referral hospital. Demographic data, operative findings, and hearing results were reviewed. Results21 cases were performed in 20 ears (1 revision). Average age at surgery was 7.98 years and average follow up was 2.1 years. Middle ear pathology identified on CT imaging was confirmed in 55% of cases while identified in 45% of cases where pre-operative imaging was non-diagnostic. 6/20 patients (30%) had an ossicular deformity. 8/20(40%) had bony ossicular fixation. 5/20(25%) had ossicular discontinuity. 2/20(10%) had facial nerve dehiscence impinging on the stapes. 15% had adhesive myringosclerosis or severe granulation causing hearing loss. Prosthetic ossiculoplasty was done in 7/21 (33.3%) of the cases, with 1 TORP, 3 PORPs, and 3 IS joint replacements. Imaging was predictive of intra-operative findings in 13/20 cases (55%). Trainees assisted in 16/21(76%) of cases. The average improvement of PTA was 11.65 dB (range −10 to 36.25), and the average ABG improved 10.19 (range −11.25 to 28.75). There were no perioperative complications or adverse events. ConclusionsThe endoscopic transcanal approach for middle ear exploration offers excellent visualization and is one of the best applications for the endoscopes in pediatric otology cases. This is particularly helpful for “unexplained” conductive hearing loss where ossicular deformity/fixation/discontinuity is suspected. The etiology of the conductive hearing loss was definitively found in 100% of cases, and can be repaired in the same sitting when applicable.