Angled Endoscopes Research Articles

Endoscopic-Assisted Presigmoid Approach to the Internal Auditory Canal. A Feasibility Study.

The retrolabyrinthine (presigmoid) approach has been utilized in various skull base surgeries but has not been fully utilized in the management of internal auditory canal (IAC) lesions, such as vestibular schwannoma (VS). Microsurgical retrolabyrinthine approach provides limited visualization of the IAC, while endoscopic-assisted techniques allow for further lateral exposure with labyrinthine preservation. Traditional approaches to the IAC have the disadvantage of hearing sacrifice or retraction of brain tissue. With the introduction of endoscopic techniques and enhanced visualization, access to this region of complex anatomy is possible. Radiomorphometric and anatomical dissection was performed on two cadaveric temporal bones. High-resolution computed tomography was used to segment and delineate the volume of the IAC. Projected accessible IAC was compared to actual postdissection data with preservation of the posterior semicircular canal (PSCC) via the retrolabyrinthine corridor. While preserving the PSCC, the 0° and 30° endoscopes visualized 57.1% and 78.6% of the IAC for cadaver 1, and 64.0% and 76.0% of the IAC for cadaver 2, respectively. Sacrificing the PSCC, the 0° and 30° endoscopes provided visualization of 78.6% 85.7% of the IAC for cadaver 1, and 88.0% and 95.1% of the IAC for cadaver 2, respectively. Retrolabyrinthine approach to resection of VS is a potentially viable hearing-preserving alternative to traditional approaches. This approach provides access to the majority of the IAC, while angled endoscopes or sacrifice of the PSCC can provide additional access toward the fundus. Further studies are needed to determine the clinical feasibility of this approach.

Endoscopy for T10 nerve sheath tumor.

Minimally invasive surgery (MIS) is increasingly being adopted for spinal intradural tumors. Through the use of conventional microscopy or exoscopy for large lobulated nerve sheath tumors, the posterior root attachment is often visualized only after mobilizing the tumor. Here, the authors describe the utility of angled endoscopy with its panoramic view for a T10 nerve sheath tumor. Gross-total extracapsular excision was achieved utilizing a minimally invasive right paraspinous approach, fenestration, lateral durotomy, sliding delivery of the tumor, sharp dissection of radicular attachments under neuromonitoring, and dural closure with oblique clips. Angled endoscopes help visualize the attachments behind large multilobulated tumors and confirm the totality of excision. The video can be found here: https://stream.cadmore.media/r10.3171/2024.1.FOCVID23214.

Neuroradiological Correlation of the Lateral Third Periventricular, Pituitary Gland and Stalk, Pineal Gland, Cerebral Aqueduct, and Foramen Magendie and Luschka With Intraventricular Neuroendoscopic Images: A Case Series.

Neuroendoscopy procedures in pediatrics have expanded beyond the endoscopic third ventriculostomy. As such, a direct and angled endoscope allows further visualization around the corner, capturing the surrounding anatomy. Intraoperative live images look different than radiological images. Hence, in this single institutional experience, we correlate neuroradiology images with intraoperative intraventricular endoscopic views of the third-fourth ventricle, pituitary, pineal gland, cerebral aqueduct, and foramen magendie and luschka. Our collective case series reveals a few interesting case scenarios of normal and abnormal findings during the procedure. Careful navigation of the neuroendoscope is crucial to prevent injury to the neurovascular bundle. A close relationship with normal anatomy from radiological imaging is necessary to prevent it from getting lost once inside the ventricular cavity.

Contralateral Nasofrontal Trephination: A Novel Corridor for a "Dual Port" Approach to the Petrous Apex.

Expanded endonasal approaches (EEAs) have proven safe and effective in treating select petrous apex (PA) pathologies. Angled endoscopes and instruments have expanded indications for such approaches; however, the complex neurovascular anatomy surrounding the petrous region remains a significant challenge. This study evaluates the feasibility, anatomic aspects, and limitations of a contralateral nasofrontal trephination (CNT) route as a complementary corridor improving access to the PA. Expanded endonasal and CNT approaches to the PA were carried out bilaterally in 15 cadaveric heads with endovascular latex injections. The distance to the PA, angle between instruments through the 2 approach portals, and surgical freedom were measured and compared. Three-dimensional DICOM-based modeling and visualization indicate that the CNT route reduces the distance to the target located within the contralateral PA by an average of 3.33 cm (19%) and affords a significant increase in the angle between instruments (15.60°; 54%). Furthermore, the vertical vector of approach is improved by 28.97° yielding a caudal reach advantage of 2 cm. The area of surgical freedom afforded by 3 different approaches (endonasal, endonasal with an endoscope in CNT portal, and endonasal with an instrument in CNT portal) was compared at 4 points: the dural exit point of the 6th cranial nerve, jugular foramen, foramen lacerum, and petroclival fissure. The mean area of surgical freedom provided by both approaches incorporating the CNT corridor was superior to EEA alone at each of the surgical targets ( P = <.001). The addition of a CNT portal provides an additional avenue to expand on the classical EEA to the PA. This study provides insight into the anatomic nuances and potential clinical benefits of a dual-port approach to the PA.

Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Surgical Anatomy of the Endoscopic Endonasal Middle-Inferior Clivectomy, Odontoidectomy, and Far-Medial Approach.

Introduction The clival, paraclival, and craniocervical junction regions are challenging surgical targets. To approach these areas, endoscopic endonasal transclival approaches (EETCAs) and their extensions (far-medial approach and odontoidectomy) have gained popularity as they obviate manipulating and working between neurovascular structures. Although several cadaveric studies have further refined these contemporary approaches, few provide a detailed step-by-step description. Thus, we aim to didactically describe the steps of the EETCAs and their extensions for trainees. Methods Six formalin-fixed cadaveric head specimens were dissected. All specimens were latex-injected using a six-vessel technique. Endoscopic endonasal middle and inferior clivectomies, far-medial approaches, and odontoidectomy were performed. Results Using angled endoscopes and surgical instruments, an endoscopic endonasal midclivectomy and partial inferior clivectomy were performed without nasopharyngeal tissue disruption. To complete the inferior clivectomy, far-medial approach, and partially remove the anterior arch of C1 and odontoid process, anteroinferior transposition of the Eustachian-nasopharynx complex was required by transecting pterygosphenoidal fissure tissue, but incision in the nasopharynx was not necessary. Full exposure of the craniocervical junction necessitated bilateral sharp incision and additional inferior mobilization of the posterior nasopharynx. Unobstructed access to neurovascular anatomy of the ventral posterior fossa and craniocervical junction was provided. Conclusion EETCAs are a powerful tool for the skull-base surgeon as they offer a direct corridor to the ventral posterior fossa and craniocervical junction unobstructed by eloquent neurovasculature. To facilitate easier understanding of the EETCAs and their extensions for trainees, we described the anatomy and surgical nuances in a didactic and step-by-step fashion.

Endoscope-Assisted Visualization of the Internal Auditory Canal Using the Middle Fossa Approach.

Angled endoscopes have been postulated to increase visualization of the internal auditory canal (IAC); however, few studies have quantified the extent of IAC visualization using endoscopes of varying angles. Preservation of the bony labyrinth in middle fossa (MF) vestibular schwannoma surgery may limit visualization of the lateral IAC. We sought to determine the extent to which IAC visualization is increased with endoscopes in these situations. Computed tomography (CT) scans were acquired before and after two cadaveric MF bony drill-outs. An atlas-based method was used to localize the IAC in the preprocedure CT and then registered with the postprocedure CT using standard image registration methods. Virtual microscope and endoscope positions and angles of approach were determined in a 3D rendering environment. Using ray casting techniques, the percentage of IAC surface area visible (unobscured by bony structures) with the microscope and 0°, 30°, and 45° endoscopes was calculated. For cadaver 1, the microscope led to visible IAC surface areas of 72%, whereas 0°, 30°, and 45° endoscopes visualized 58%, 79%, and 84%, respectively. For cadaver 2, the microscope led to visible surface areas of 67%, whereas the same endoscopes visualized 66%, 84%, and 84%, respectively. Using a microscope yields similar proportions of visible IAC surface area to a 0° endoscope in MF bony drill-outs. Increased visualization of the IAC is possible with more angled endoscopes. Using angled endoscopes may facilitate improved tumor dissection in the lateral IAC with neural and vascular preservation in vestibular schwannoma surgery aimed at hearing preservation.

Recreating the microscopic direct access Draf2a frontal sinusotomy in the endoscopic era and comparison to an angled instrument approach.

Microscopic Draf2a frontal sinusotomy relied on direct access. However, the modern-day endoscopic approach is hindered by the anterior-posterior dimensions of the frontal recess. The nasofrontal beak, angled endoscopes, and variable frontal recess anatomy make the surgery challenging. Carolyn's window frontal sinusotomy removes the limitation of anterior-posterior dimensions and is an endoscopic version of the microscopic Draf 2a. This study aims to compare the perioperative outcomes and morbidity from endoscopic direct access Draf2a compared to angled access Draf2a. Consecutive adult patients (>18years) seen at a tertiary referral clinic who underwent Draf2a frontal sinus surgery using either endoscopic direct access (Carolyn's window) or endoscopic angled instrumentation were included. Patients who underwent Carolyn's window were compared to those with angled Draf 2a frontal sinusotomy. One hundred patients (age 51.96 ± 15.85years, 48.0% female, follow-up 60.75 ± 17.34months) were included. 44% of patients used Carolyn's window approach. 100% [95% CI 98.2-100%] of patients achieved successful frontal sinus patency. Both groups were comparable for early morbidities (bleeding, pain, crusting, and adhesions) and late morbidities (retained frontal recess partitions). There were no other morbidities in the early and late postoperative periods. The endoscopic direct access Draf2a, or Carolyn's window, removes the anteroposterior diameter limitation. The frontal sinus patency and early and late surgical morbidities of direct access Draf2a were comparable with the angled Draf2a frontal sinusotomy. Surgical modifications, often with drills and bone removal, can be successfully made to enhance access in endoscopic sinus surgery without concern for additional morbidity.

Anatomical step-by-step dissection of common approaches to the third ventricle for trainees: surgical anatomy of the anterior transcortical and interhemispheric transcallosal approaches, surgical principles, and illustrative pediatric cases.

To create a high-quality, cadaver-based, operatively oriented resource documenting the anterior transcortical and interhemispheric transcallosal approaches as corridors to the third ventricle targeted towards neurosurgical trainees at all levels. Two formalin-fixed, latex-injected specimens were dissected under microscopic magnification and endoscopic-assisted visualization. Dissections of the transcortical and transcallosal craniotomies with transforaminal, transchoroidal, and interforniceal transventricular approaches were performed. The dissections were documented in a stepwise fashion using three-dimensional photographic image acquisition techniques and supplemented with representative cases to highlight pertinent surgical principles. The anterior transcortical and interhemispheric corridors afford excellent access to the anterior two-thirds of the third ventricle with varying risks associated with frontal lobe versus corpus callosum disruption, respectively. The transcortical approach offers a more direct, oblique view of the ipsilateral lateral ventricle, whereas the transcallosal approach readily establishes biventricular access through a paramedian corridor. Once inside the lateral ventricle, intraventricular angled endoscopy further enhances access to the extreme poles of the third ventricle from either open transcranial approach. Subsequent selection of either the transforaminal, transchoroidal, or interforniceal routes can be performed through either craniotomy and is ultimately dependent on individual deep venous anatomy, the epicenter of ventricular pathology, and the concomitant presence of hydrocephalus or embryologic cava. Key steps described include positioning and skin incision; scalp dissection; craniotomy flap elevation; durotomy; transcortical versus interhemispheric dissection with callosotomy; the aforementioned transventricular routes; and their relevant intraventricular landmarks. Approaches to the ventricular system for maximal safe resection of pediatric brain tumors are challenging to master yet represent foundational cranial surgical techniques. We present a comprehensive operatively oriented guide for neurosurgery residents that combines stepwise open and endoscopic cadaveric dissections with representative case studies to optimize familiarity with third ventricle approaches, mastery of relevant microsurgical anatomy, and preparation for operating room participation.

Full-endoscopic removal of third ventricular colloid cysts: technique, results, and limitations.

Colloid cysts (CCs) are rare benign lesions that usually arise from the roof of the third ventricle. They may present with obstructive hydrocephalus and cause sudden death. Treatment options include ventriculoperitoneal shunting, cyst aspiration, and cyst resection microscopically or endoscopically. This study aims to report and discuss the full-endoscopic technique for removing colloid cysts. A 25°-angled neuroendoscope with an internal working channel diameter of 3.1 mm and a length of 122 mm is used. The authors described the technique of resecting a colloid cyst by a full-endoscopic procedure and evaluated the surgical, clinical, and radiological results. Twenty-one consecutive patients underwent an operation with a transfrontal full-endoscopic approach. The swiveling technique (grasping the cyst wall and rotational movements) was used for CC resection. Of these patients, 11 were female, and ten were male (mean age, 41 years). The most frequent initial symptom was a headache. The mean cyst diameter was 13.9 mm. Thirteen patients had hydrocephalus at admission, and one needed shunting after cyst resection. Seventeen patients (81%) underwent total resection; 3 (14%), subtotal resection; and 1 (5%), partial resection. There was no mortality; one patient had permanent hemiplegia, and one had meningitis. The mean follow-up period was 14 months. Even though microscopic resection of cysts has been widely used as a gold standard, successful endoscopic removal has been described recently with lower complication rates. Applying angled endoscopy with different techniques is essential for total resection. Our study is the first case series to show the outcomes of the swiveling technique with low recurrence and complication rates.

Intraoperative endoscope view classification of neurovascular compression in hemifacial spasm condition: a single neurosurgeon prospective cross-sectional study.

This was a prospective, single center, single neurosurgeon, cross-sectional study conducted from November 2020 to August 2022. All patients received EAMVD, and the NVC culprit vessel, compression site, severity, and type were analyzed using a 30-degree endoscope. All 29 patients had successful interposition EAMVD without postoperative symptoms. The most common NVC site was REX (18 in 29 cases), the most common vessel to compress the seventh nerve was AICA (23 in 29 cases), while the most common type of NVC was loop (22 in 29 cases). NVC severity: 17 cases of mild compression, 4 cases of moderate compression, and 8 cases of severe compression. Without an angled telescope, we will miss the NVC in 12 cases (41.3%). EAMVD using an angled endoscope is a promising technique for treating hemifacial spasm. Intraoperative analysis of NVC can lead to a better understanding of the patterns of compression and may help in selecting appropriate decompression techniques.

Isolated Frontal Sinus Mucormycosis Post Covid 19-external Approaches Revisited!

Isolated frontal sinus involvement in mucormycosis is seen very infrequently. Recent technological advances including image guided navigation and angled endoscopes have shifted paradigm towards minimally invasive surgeries. Open approaches are still relevant for the disease of frontal sinus with lateral extension where effective clearance cannot be obtained if approached endoscopically. The objective of this study was to describe the presentation and management of patients of mucormycosis with isolated frontal sinus involvement with help of external approaches. The available records of the patients were retrieved and analysed. The literature, the associated contributory clinical features and management techniques were reviewed. 4 patients presented with isolated frontal sinus mucor involvement. 3 out of 4 patients had history of diabetes mellitus (75%). All patients had history of covid-19 infection (100%). 3 out of 4 patients had unilateral frontal sinus involvement and were operated by Lynch Howarth approach. Mean age of presentation was 46 years with male predominance. Bicoronal approach was used in one case with bilateral involvement. Although conservative endoscopic surgeries are preferred nowadays for frontal sinus clearance but the extensive bony destruction with lateral extension in our series of patients with isolated frontal sinus mucormycosis warranted the need for open procedures.

A COMPARISON OF OTOENDOSCOPY WITH OTOMICROSCOPY FOR DIAGNOSTIC AND SURGICAL EVALUATION

Introduction: The tympanic membrane is the window into the middle ear, yet simply looking at it with the naked eye is insufcient to identify every condition. To visualize and document middle ear diseases, otologists now use an otomicroscope and an otoendoscope, which are required for surgical treatment [1]. Chronic Otitis Media is one of the common causes of hearing impairment and disability. The microscope revolutionized the surgical management of ear diseases, but the basic optical properties of the microscope have remained the same for the last 30 years [2]. The present study was intended to evaluate and compare the visualization of middle ear structures using an otomicroscope and 0 and 30-degree angled endoscopes in cases of Chronic Otitis Media (mucosal type) and also to make a surgical comparison in terms of advantages and disadvantages of the endoscope with the microscope in myringoplasty. Aims And Objectives: To visualize the middle ear structures by 0- and 30-degree angled endoscope and otomicroscope and to compare the results of endoscopic myringoplasty with that of myringoplasty done by using an operating microscope. Material And Methods: This was a comparative prospective study in which 100 patients, above the age of 15 years were examined by otomicroscopy and otoendoscopy. The visualization of various middle ear structures and the results of myringoplasty done with an endoscope and microscope were compared and statistically analysed. 30-degree angled endosc Results: ope provided better visualization of middle ear structures than with the microscope. Endoscopic myringoplasty showed good results in terms of accessibility, duration of surgery, postoperative pain, and cosmesis. Otoendoscopy provided better visualization of various middle ear Conclusion: structures as well as showed good outcomes in surgical aspects. Thus, endoscopes can be utilized for better diagnosis, and it can be a good alternative to microscopic myringoplasty

Sternberg’s canal: a rare site of CSF leak—our experience and management of a series of cases at a tertiary care hospital in South India

Abstract Background The lateral craniopharyngeal canal or Sternberg’s canal is located in the postero-lateral part of the sphenoid sinus. It is the weakest area of the skull base, originating due to defective fusion during embryological development in a small proportion of individuals. Hence, it can give rise to CSF leaks from that region. Due to the proximity of this region to the internal carotid artery, optic nerve, and cavernous sinus, it proves to be challenging to repair these defects. The exact location, role in the causation of CSF leaks, and clinical presentation with arachnoid herniation are also subject to much controversy. Results In our case series, we describe 7 patients with the rare clinical entity of CSF leak from the Sternberg’s canal, who had a mean age of 38.4 years, 4 of whom also had an arachnoid herniation through the canal. One patient already underwent prior endoscopic surgery for the CSF leak. We highlight a trans-nasal trans-sphenoid approach with multi-layer closure, i.e., fat plug, fascia, and a naso-septal flap with the use of an additional layer of muscle in one of the cases, following which all had good outcomes. Since the primary concern with this rare clinical scenario is correct identification and adequate exposure of the leak for repair, we additionally undertook a trans-pterygoid approach in 2 of our patients. Conclusions The key to the successful repair of the Sternberg’s canal leak lies in its accurate identification and exposure. In our series, we achieved good exposure by drilling the pterygoids and lateral sphenoid walls along with the use of angled endoscopes for visualization. Our case series highlights the linear relation of elevated BMI with spontaneous CSF leaks in the absence of benign intracranial hypertension and the reinforcement of repair with the use of a harvested naso-septal flap. Our multi-layered closure ensured good results and no recurrence of a leak in any of our patients.

Clinical application of a self-developed mouth opener with a tongue base retractor in the operation of deep part of tongue base

Objective:To test the application effect of a self-developed mouth opener with a tongue base retractor in the operation of the deep part of tongue base. Methods:The tongue base surgical field was exposed by using a self-developed mouth opener with a tongue base retractor in 8 patients who underwent deep tongue base operation via oral approach, the difficulty of operation, the effect of exposure of operation field, the tear of mucous membrane of the pharynx arch and the risk of tongue paralysis were observed. Results:The self-made mouth opener can expose the deep operative field of the tongue root by using the self-provided tongue root retractor during the operation, and the operation is conducted under the guidance of angle endoscope. The operative field of 8 patients was well exposed during the whole operation, there was no pharyngeal mucosa tearing and postoperative tongue paralysis. Conclusion:The self-made mouth opener has the advantages of simple operation, good exposure effect and less complications, but it needs rigid bending instruments in some operations.

HAPPY: Hip Arthroscopy Portal Placement Using Augmented Reality.

Correct positioning of the endoscope is crucial for successful hip arthroscopy. Only with adequate alignment can the anatomical target area be visualized and the procedure be successfully performed. Conventionally, surgeons rely on anatomical landmarks such as bone structure, and on intraoperative X-ray imaging, to correctly place the surgical trocar and insert the endoscope to gain access to the surgical site. One factor complicating the placement is deformable soft tissue, as it can obscure important anatomical landmarks. In addition, the commonly used endoscopes with an angled camera complicate hand-eye coordination and, thus, navigation to the target area. Adjusting for an incorrectly positioned endoscope prolongs surgery time, requires a further incision and increases the radiation exposure as well as the risk of infection. In this work, we propose an augmented reality system to support endoscope placement during arthroscopy. Our method comprises the augmentation of a tracked endoscope with a virtual augmented frustum to indicate the reachable working volume. This is further combined with an in situ visualization of the patient anatomy to improve perception of the target area. For this purpose, we highlight the anatomy that is visible in the endoscopic camera frustum and use an automatic colorization method to improve spatial perception. Our system was implemented and visualized on a head-mounted display. The results of our user study indicate the benefit of the proposed system compared to baseline positioning without additional support, such as an increased alignment speed, improved positioning error and reduced mental effort. The proposed approach might aid in the positioning of an angled endoscope, and may result in better access to the surgical area, reduced surgery time, less patient trauma, and less X-ray exposure during surgery.

Rejuvenating The Shunned Art of Diagnostic Nasal Endoscopy Using Angled Endoscopes- A Descriptive Study

Nasal endoscopy is a minimally invasive, routine outpatient diagnostic procedure. With 0 degree scope being used as the first and often only endoscope in diagnostic nasal endoscopy, this study will explicate use of angled scopes to identify anatomical variants and common disease pointers. A Cross-sectional descriptive study involving 756 subjects, between age group of 12-80 years with chronic nasal complaints. All subjects underwent diagnostic nasal endoscopy with 0-, 30- &amp; 70-degree endoscopes. Common anatomical variants along with disease markers were identified. Anatomical variants embedded in lateral wall of nose such as accessory maxillary ostium (AMO) &amp; medialized uncinated (MU), were seen better on 30 &amp; 70 degree scopes (AMO -12% &amp; 12.8% respectively &amp; MU -7.6 and 8.1% of study population respectively), when compared to 0 degree scopes (AMO-5.6% &amp; MU-7 %). Disease pointers projected a general trend of being better visualized on angled scopes of 30 &amp; 70 degree endoscopes. It included discharging meati (27.9 % &amp; 26.3% subjects on 30 &amp; 70 degree vs 25 % subjects on 0 degree), polyposis (20.2 &amp; 19.6% on 30 &amp; 70 degree vs 13% on 0), eschar (6.1% &amp; 5.7% on 30 &amp; 70 degree vs 4.5% on 0), CSF rhinorrhoea (1.3% &amp; 2.1% on 30 &amp; 70degree vs 0.5% on 0). With inclusion of angled scopes in routine nasal endoscopies, one gains capability to diagnose early disease processes, mucosal changes and learn intra nasal anatomy better. The angulation of lenses provides a better field of vision with appropriate magnification and illumination.

Three-Dimensional Printed Models to Accelerate Resident Surgical Learning Curve for Standard Endoscopic Sinus Surgery Techniques.

Background: Endoscopic sinus surgery presents significant visuospatial challenges to surgical trainees. We tested the utility of novel 3D printed models to simulate sinus surgery tasks to improve endoscopic skillsets in resident trainees. Methods: This was a prospective quality improvement study of 10 ENT residents (PGY1-5). Participants rotated through 4 stations with different 3D simulation training modules designed to enhance endoscopic skillsets in the axial, sagittal and coronal planes (e.g., straight forceps to grasp a bead from a ledge, angled instruments to cannulate openings). Participants completed a self-assessment survey on the subjective sinus surgical skills using a visual analog scale before and after tasks. Two- tailed paired T-tests were used to analyze the data. Results: All residents rated their post-intervention "overall sinus surgery skills" higher than pre-intervention. They rated simulations to provide more significant utility as an adjunct to surgical education after the intervention. All but one participant reported improved spatial awareness working with the endoscopes and surgical instruments. There was subjectively improved proficiency in using 0-degree and angled endoscopes as well as cutting, grasping, and curved instruments after the intervention. The simulations led to subjective improvements in spatial awareness, bimanual dexterity, and increased confidence in selecting correct surgical instruments. Conclusion: Our set of novel 3D printed models to improve sinus surgery skillset was well accepted by the resident cohort. The 3D models can serve as an adjunct tool to traditional residency education.

Quantitative Study of Bone Removal Region in Transcanal Endoscopic Approach to the Attic and Antrum Using a 70° Endoscope.

Transcanal endoscopic ear surgery enables surgeons to operate with few blind areas, and using an angled endoscope expands its usefulness. We have previously reported the usefulness of a 70° endoscope in transcanal endoscopic ear surgery, but no quantitative study has been performed. We quantitatively clarified the difference between a microscope and various endoscopes in the bone removal region, especially a 70° endoscope, in the transcanal approach. A temporal bone model for ear surgery training was used to compare the use of a microscope, a 0° endoscope, a 30° endoscope, a 45°endoscope, and a 70° endoscope. The drilled mass during atticotomy or atticoantrostomy and the size of the reconstructed graft were measured when the formed pseudo-lesion was removed. The amount of bone excision was 57% and the size of the reconstructed graft was 32% when using a 70° endoscope compared with the case of using a microscope, both of which were the smallest of the various endoscopes. It was quantitatively shown that using a 70° endoscope in transcanal endoscopic ear surgery reduced the bone removal region. We believe that a 70° endoscope is a useful tool for performing a minimally invasive and reliable surgery.

Temperature and luminosity outputs of endoscopes used in transcanal endoscopic ear surgery: an experimental study.

To establish the relationship between endoscope temperatures and luminosity with a variety of light source types, endoscope ages, endoscope sizes, angles and operative distance in transcanal endoscopic ear surgery. Transcanal endoscopic ear surgery was simulated in an operating theatre using 7 mm plastic suction tubing coated in insulating tape. An ATP ET-959 thermometer was used to record temperatures, and a Trotec BF06 lux meter was used to measure luminosity. Luminosity and temperature recordings were taken at 0 mm and 5 mm from the endoscope tip. Thermal energy transfer from operating endoscopes is greatest when: the light intensity is high, there is a light-emitting diode light source and the endoscope is touching the surface. Additionally, larger-diameter endoscopes, angled endoscopes and new endoscopes generated greater heat. It is recommended that operative light intensity is maintained at the lowest level possible, and that the surgeon avoids contact between patient tissues and the endoscope tip.

Endonasal endoscopic removal of intra-orbital (extralacrimal, extraconjunctival) oculosporidiosis: Anatomical and surgical considerations.

This report illustrates the successful removal of a proper intra-orbital oculosporidiosis (extralacrimal, extraconjunctival) exclusively by the endonasal endoscopic approach. It also introduces the naso-orbital pseudofontanelle as an important surgical landmark and describes a hitherto undefined intra-orbital extramucosal three-dimensional potential wedge that harbored the Rhinosporidium seeberi infestation as a nodular conglomerate. The patient, a 50-year-old woman, was operated on three years ago for rhinosporidiosis of the nasal cavity and the distal lacrimal drainage system (lacrimal sac and nasolacrimal duct). The resulting alterations in regional anatomy were evident on imaging. They could explain the present recurrence and formation of the pseudofontanelle that allowed the conglomerate to bulge through the lateral nasal wall on digital pressure, making endoscopic intervention feasible. The primary principle for adopting this approach was to protect the facial skin from possible seeding. With an angled endoscope, the pseudofontanelle was breached and the intra-orbital extramucosal wedge between the bony orbital wall and the peri-orbita entered. The nodules that formed the conglomerate were densely adherent with the peri-orbita and skin. They were carefully and meticulously removed to avoid inadvertent injury to vital intra-orbital structures. Endonasal endoscopic intervention for a true intra-orbital oculosporidiosis has never been documented before. The surgical approach, the newly defined anatomical domain for the intra-orbital extramucosal oculosporidiosis, and the concept of pseudofontanelle characterize this report as a novel clinical experience worth presenting.