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.

Mid-term evaluation of the surgical management of patulous Eustachian tube dysfunction: a STROBE observational study

INTRODUCTION

Patulous Eustachian tube (PET) is a condition affecting approximately 0.3% to 6.6% of the population, with autophony being the predominant complain. The management of PET lacks a well-defined standard in the literature as no effective medical treatments have been documented but various surgical options are available. This study aims to report mid-term outcomes following surgical management of PET.

MATERIALS AND METHODS

All patients who underwent surgical intervention for PET between September 2017 and June 2022 were enrolled. Data encompassing general demographics, quality of life (GBI), and procedure-specific data were collected.

RESULTS

A total of 30 PET cases (in 19 patients) underwent surgical intervention including 9 injections of hyaluronic acid, 13 fat injections, 6 endoscopic shim insertions, 1 cartilage graft, and 1 injection of hydroxy apatite. After an average follow-up of 22 ± 14 months, 16 cases (53%) achieved complete symptom relief, while 8 cases (26.6%) reported partial relief. Additionally, 11(36%) cases required multiple surgeries. No specific surgical technique demonstrated superiority. Quality of life improved in 77% of cases based on 10 out of 13 GBI collected. Recurrence of PET symptoms occurred on average 10.6 ± 9.7 months after initial surgery, with an estimated global risk of 75% at 3 years. Transient serous otitis media was observed in only 4 cases (13.3%).

CONCLUSION

Surgical intervention for PET was found to be effective, achieving complete symptom relief in 53% of cases and significantly improving quality of life 2 years post-surgery. However, a substantial portion of cases necessitated one or more re-interventions. The durability of effectiveness appears to diminish over time.

Quantitative measurement of airborne particles during endoscopic and microscopic ear surgery in the operating room

OBJECTIVE

This study aimed to quantitatively investigate airborne particle load in the operating room during endoscopic or microscopic epitympanectomy or mastoidectomy.

METHOD

In the transcanal endoscopic ear surgery group, drilling was performed underwater. A particle counter was used to measure the particle load before, during and after drilling during transcanal endoscopic ear surgery or microscopic ear surgery. The device counted the numbers of airborne particles of 0.3, 0.5 or 1.0 μm in diameter.

RESULTS

The particle load during drilling was significantly higher in the microscopic ear surgery group (n = 5) than in the transcanal endoscopic ear surgery group (n = 11) for all particle sizes (p < 0.01). In the transcanal endoscopic ear surgery group, no significant differences among the particle load observed before, during and after drilling were seen for any of the particle sizes.

CONCLUSION

Bone dissection carries a lower risk of airborne infection if it is performed using the endoscopic underwater drilling technique.

Initial Experience With Robotic-Assisted Otologic and Lateral Skull Base Surgery

Robotic-assisted surgery has gained popularity for otolaryngology procedures. It provides high-definition images and surgical precision to perform diverse procedures. It is an alternative to the operating microscope, endoscope, or exoscope when reaching hidden anatomical structures in the ear. In this proof-of-concept study, we aim to demonstrate the possibility of using a robotic-assisted device to perform ear surgery in conjunction with the microscope or the endoscope. In total, there were 9 ear and lateral skull base procedures performed with the use of robotic-assisted surgery. All surgeons underwent surveys to assess the performance and workload of the device compared to the microscope or endoscope. There were no postoperative complications. Robotic-assisted surgery was optimal for providing high image quality, ergonomics, and maintaining surgical performance. The size of the device and mental demand were higher compared to the microscope or endoscope. Robotic-assisted surgery can be an adjuvant to perform otologic and neurotologic surgery.

Surgical results of 29 ears with congenital middle ear anomalies; Microscopic vs. endoscopic ear surgery

OBJECTIVE

Although congenital middle ear anomalies include various types of ossicular anomalies, all of these can be treated by ossiculoplasty or stapes surgery. Transcanal endoscopic ear surgery (TEES) is a minimally invasive surgical method for middle ear disease with an excellent surgical view that has been widely adopted worldwide. To determine the efficacy of TEES for middle ear anomalies, we describe the surgical results and compare the hearing outcomes between patients treated by TEES and microscopic ear surgery (MES).

METHODS

A total of 39 ears with congenital middle ear anomalies were treated surgically at the University Hospital of Kochi Medical School between January 2011 and December 2021. In total, 29 ears of 23 patients were included in the study. Demographics, type of anomaly, surgical methods, pre- and postoperative hearing thresholds, and surgical complications were investigated by retrospective chart review.

RESULTS

Of the 29 ears, 11 were treated by MES and 18 were treated by TEES. There were no differences in sex, age, preoperative hearing thresholds, or rate of stapes surgery between the two groups. The mean air-bone gap improvement was 20.6 dB in the MES group and 28.8 dB in the TEES group; these values were not significantly different. The median operation time was not significantly different between the MES and TEES groups (125 and 130 min, respectively). The improvements of air conduction in class 1 and 2 (stapes surgery) and class 3 (ossiculoplasty) cases were also not different between the groups.

CONCLUSIONS

TEES achieved comparable hearing outcomes to MES without postauricular or endaural incisions. Further, class 1 and 2 anomalies demonstrated hearing improvement similar to class 3 without major complications. Since the surgical field limited around the ossicular chain, coupled with the fact that the middle ear anomaly itself does not exhibit inflammation leading to unfavorable bleeding, TEES is a feasible surgical procedure for all types of congenital ossicular anomalies.

Intralabyrinthine schwannoma: Surgical management and cochlear lumen preservation

The present video reports the surgical removal of an intralabyrinthine schwannoma. The video contains patient's medical history, preoperative radiological evaluations and detailed description of surgical steps of the procedure, consisting in labyrinthectomy, cochleostomy and insertion of a dummy electrode in the preserved cochlear lumen within the context of a subtotal petrosectomy.

Educational Benefit of the Three-Dimensional Exoscope Versus Operating Microscope in Otologic Surgery

OBJECTIVE

To compare observation of otologic surgery using a traditional operating microscope (OM) and a three-dimensional exoscope.

STUDY DESIGN

Prospective, nonrandomized, noncontrolled study.

SETTING

Tertiary care center.

METHODS

Senior medical students and otolaryngology trainees observing otologic surgery performed with OM and exoscope were asked to complete a questionnaire comparing the two experiences. The key variables were image clarity, depth perception, observer's level of motion sickness during the surgery, the participant's understanding of middle ear anatomy, and their overall preference between OM and exoscope.

RESULTS

Twenty-two observers participated in the study. Subjective clarity of the image was significantly better with the exoscope compared with the OM (9.7 ± 0.6 versus 6.9 ± 1.7, p = 0.0004) as well as the depth perception (9.25 ± 0.87 versus 5 ± 2.69, p = 0.0007). Observers subjectively had an improved understanding of middle ear anatomy after observing an exoscopic surgery, but not a microscopic surgery. All but one observer preferred the exoscope.

CONCLUSION

The three-dimensional exoscope may be a valuable educational tool for teaching trainees otologic surgery. More objective studies are needed in the future to assess the degree of improvement.

Low-Lying Tegmen and Surgical Outcomes Following the Middle Cranial Fossa Repair of Superior Canal Dehiscence

OBJECTIVE

To compare treatment response from the middle cranial fossa repair of superior canal dehiscence (SCD) between cases with and cases without low-lying tegmen (LLT).

STUDY DESIGN

Cohort study.

SETTING

Single tertiary care institution.

METHODS

Two investigators independently reviewed preoperative high-resolution temporal bone computed tomography images and classified the ipsilateral tegmen as either "low-lying" or "control." Patients completed a symptom questionnaire and underwent audiometric testing pre- and post-operatively. Multivariable regression models assessed for symptomatic resolution and audiometric improvement following surgery with tegmen status as the primary predictor. Models controlled for patient age, sex, bilateral SCD disease, dehiscence location, prior ear surgery status, surgery duration, and follow-up duration.

RESULTS

Among a total of 410 cases included, we identified 121 (29.5%) LLT cases. Accounting for all control measures, patients with LLT were significantly less likely to experience overall symptom improvement (adjusted odds ratio: 0.32, 95% confidence interval [CI]: 0.18-0.57, p < .001) and reported a significantly lower proportion of preoperative symptoms that resolved following surgery (adjusted β: -25.6%, 95% CI: -37.0% to -14.3%, p < .001). However, audiometric outcomes following surgery did not differ significantly between patients with and patients without LLT.

CONCLUSION

This is the first investigation on the relationship between LLT and surgical outcomes following the middle fossa repair of SCD. Patients with LLT reported less favorable symptomatic response but exhibited a similar degree of audiometric improvement.

Training in Endoscopic Ear Surgery: A Scoping Review

OBJECTIVE

Despite the increasing popularity of Endoscopic Ear Surgery (EES), there is a lack of evidence to guide trainees as they introduce EES into practice. This review aims to evaluate training in EES including the optimal introductory procedures, methods of training, the learning curve, and the determination of competency in EES. In addition, this review seeks to identify any areas falling within these themes requiring further clarification.

DATA SOURCES

A database search of Pubmed, Embase and the Cochrane Library was conducted in June 2022. Original articles, systematic reviews, and meta-analyses reporting on training in EES, introduction into practice, learning curves, and competency assessment were included.

REVIEW METHODS

A scoping review was carried out in accordance with the Joanna Briggs Institute guidelines and reported according to PRISMA guidelines for scoping reviews. A qualitative assessment of results grouped thematically was performed.

RESULTS

Twenty-eight studies met the inclusion criteria, with 24 rating as "fair" or "good" on quality assessment. Surgical simulation was the most frequently described method of training as utilized in 11 studies. The most suggested introductory procedure was tympanoplasty which was advocated for in five studies. Heterogeneity existed in the outcomes and methodologies used to measure EES learning curves, with an overreliance on surgical times. No robust definition of competency in EES procedures exists at present.

CONCLUSIONS

Surgical simulation appears to be a beneficial training methodology for EES. However, there is a marked lack of objective data to describe the optimal introductory procedures or assessment of competency in EES. Laryngoscope, 133:3269-3278, 2023.

[Experiences with endoscopic ear surgery of a German tertiary hospital for otolaryngology]

BACKGROUND

The aim of this article is to report on the integration of endoscopic ear surgery (EES) into daily clinical practice.

MATERIAL AND METHODS

In a monocentric prospective study, the endoscopy unit was set up during even weeks over a period of 10 months and the procedure was primarily started endoscopically via a transmeatal approach. In odd weeks, the endoscopy was omitted. A total of 60 procedures in 59 patients were evaluated. Points of comparison were intraoperative vision, incision-suture time, postoperative hearing outcome, and postoperative otoscopic findings.

RESULTS

With the exception of the facial nerve (p = 0.15 Mann-Whitney U‑test), the EES showed significantly improved visualization of all areas in the middle ear. The incision-suture times were similar in both methods. If bimanual placement of an ossicular prosthesis was necessary, the incision-suture time increased disproportionately (MES: 57.18 ± 9.7 min, EES: 76.83 ± 24.99 min; p = 0.019, *). There were no statistically significant changes related to hearing outcomes when comparing EES with the microscopic technique. There were no postoperative complications in the EES surgery group.

CONCLUSION

Integration of EES proved to be successful and advantageous in a real patient collective at this location.

[Clinical application of retrosigmoid approach for BONEBRIDGE implantation after auricle reconstruction using expanded postauricular flap]

Objective: To explore the safety and reliability of retrosigmoid approach BONEBRIDGE implantation in patients with auricle reconstruction using skin expansion flap. Methods: A retrospective analysis was conducted on 43 congenital aural atresia cases (43 ears) who underwent BONEBRIDGE implantation from September 2019 to January 2023 in Beijing Tongren Hospital. 30 males and 13 females were included in this work. The implantation age was 9-36 years old (median age=10 y/o). All cases underwent auricle reconstruction surgery using the posterior ear flap expansion method, with 36 cases using the single expanded postauricular flap method and 7 cases using two-flap method. BONEBRIDGE implant surgery was performed during the third stage of auricle reconstruction or after all stages. The hearing improvements were evaluated by comparing the changes in pure tone hearing threshold and speech recognition rate of patients before and after BONEBRIDGE implantation. Routine follow-up was conducted to observe the hearing results and complications. SPSS 14.0 software was applied for data statistical analysis. Results: All 43 patients healed well and had no surgical complications when discharge. The average bone conduction hearing threshold after surgery was (8.2±6.6) dBHL, and there was no statistically significant difference compared to the preoperative [(8.1±5.7) dBHL] (P=0.95). After surgery, the threshold of hearing assistance with power on was significantly lower than that without hearing assistance [(32.8±4.6) dBHL vs (60.5±5.5) dBHL], and the difference was statistically significant (P<0.001). The speech recognition rate of monosyllable words, disyllabic words and short sentences in quiet environment increased to 72%, 84%, and 98% respectively. The differences were statistically significant (P<0.001). The speech recognition rate of monosyllabic words, disyllabic words, and short sentences in noise environment was significantly increased by 70%, 80%, and 92% respectively (P<0.001). After a follow-up of 4 to 47 months (median=24 months), the hearing results were stable and the aesthetic outcomes were satisfying. One patient had delayed hematoma around coil of the implant. After aspiration and compressed dressing for one week, hematoma was not recurrent. Conclusion: For patients after auricle reconstruction using expanded postauricular flap, the preference of retrosigmoid approach is a good choice in terms of safety and reliability of operation, as well as aesthetic appearance.

Management of a Posterior Mesotympanic Cholesteatoma using the Transcanal Endoscopic Approach

With the constant evolution in the role of endoscopy in middle ear surgery, this article presents a technical note on the transcanal endoscopic approach to resection of a cholesteatoma limited to the posterior mesotympanum. We believe that this technique provides a suitable, minimal-invasive alternative to the classic microscopic transmastoid approach.

Comparison of artefact reduction possibilities with the new active transcutaneous bone conduction implant (Bonebridge)

OBJECTIVE

This study aimed to evaluate the possibilities of artefact reduction using different anatomical implant positions with the Bonebridge bone-conduction hearing implant 602 for a patient with an acoustic neuroma requiring regular diagnostic magnetic resonance imaging of the tumour position.

METHOD

Three implant positions and magnetic resonance imaging examinations with and without customised sequences for metal artefact suppression were investigated. The diagnostic usefulness was rated by a radiologist (qualitative evaluation), and the relation between the area of artefact and the total head area was calculated (quantitative evaluation).

RESULTS

Following the qualitative analysis, the radiologist rated the superior to middle fossa implant placement significantly better for diagnostic purposes, which is in agreement with the calculated artefact ratio (p < 0.0001). The customised slice-encoding metal artifact correction view-angle tilting metal artifact reduction technique sequences significantly decreased the relative artefact area between 5.13 per cent and 25.02 per cent. The smallest mean artefact diameter was found for the superior to middle fossa position with 6.80 ± 1.30 cm (range: 5.42-9.74 cm; reduction of 18.65 per cent).

CONCLUSION

The application of artefact reduction sequencing and special anatomical implant positioning allows regular magnetic resonance imaging in patients with the bone-conduction hearing implant 602 without sacrificing diagnostic imaging quality for tumour diagnosis.

Updates in paediatric cholesteatoma

PURPOSE OF REVIEW

The management of paediatric patients with cholesteatoma is complex, as the disease process is more aggressive in children than adults. New technologies and practice adaptations currently help optimize the surgical management and monitoring of these challenging patients.

RECENT FINDINGS

Several options of surgical management are available and are associated with equal if not improved outcomes. Technologic advancements in endoscopic ear surgery, the discovery of chemical-assisted dissection of cholesteatoma and advanced imaging protocols have enabled surgeons to better care for patients with this complex disease process.

SUMMARY

The advances in endoscopic ear surgery, the discovery of Mesna as a chemically assisted dissection agent to improve recidivism rates and the use of specific diffusion-weighted MRI protocols enable the otologic surgeon to better care for these paediatric patients.

Endoscopic Ear Surgery in Dhulikhel Hospital: A decade of Experience

Endoscopic ear surgery is one of the most commonly performed surgeries in Dhulikhel hospital. In the past eleven years, there have been different endoscopic ear surgeries performed with a very good outcome. The main benefit of endoscopic ear surgery is; to let the surgeon see better, proceed with the surgery through the trans-canal, teaching and training of the students. There are some drawbacks of endoscopic ear surgery like the one-handed technique and learning curve. With repeated practice and the help of motion parallax, the trainee can overcome the drawback of the procedure.

Endoscopic Ear Surgery for Congenital Cholesteatoma in Children

BACKGROUND

Endoscopic ear surgery is a promising technique for removing congenital cholesteatoma in children. It can provide greater visual access to hidden areas of the middle ear and facilitate middle-ear manipulation. This study compares a single-center experience in manag- ing congenital cholesteatoma with an endoscopic approach with that in managing congenital cholesteatoma with a conventional microscopic approach.

METHODS

Records of consecutive patients aged under 8 with congenital cholesteatoma confined to the middle ear at our tertiary referral hospital from January 2013 to December 2018 were retrospectively reviewed. Operation time, hospital stay, postoperative complications, and recurrence/residue of congenital cholesteatoma were compared between patients receiving microscopic versus endoscopic surgery.

RESULTS

A total of 33 pediatric patients aged from 19 months to 7 years were enrolled; 12 children underwent microscopic surgery, and 21 received an endoscopic approach for removing congenital cholesteatoma. The mean operative time was 1.61 hours for the microscopic group and 1.49 hours for the endoscopic group without statistical difference. No postoperative sensorineural hearing loss and complications were reported. Four cases of recurrence/residue were observed on the follow-up endoscopic exam or computed tomography, and no differences were shown between the 2 groups. Of the total patients, 94.7% (n=11) in the microscopic group and 90.5% (n=19) in the endoscopic group demonstrated an intact tympanic membrane without perforation or retraction after surgery. No audiological differences were reported between the 2 groups.

CONCLUSION

Endoscopic ear surgery can effectively and safely remove congenital cholesteatoma in children and is not inferior to conventional microscopic approaches.

"Transcanal view" computed tomography reformat: Applications for transcanal endoscopic ear surgery

PURPOSE

Transcanal endoscopic ear surgery (TEES) is an increasingly used surgical approach for otologic surgeries, but no en face preoperative imaging format currently exists. We aim to assess the utility of a transcanal high resolution computed tomography (HRCT) reformat suitable for TEES preoperative planning.

MATERIALS AND METHODS

Preoperative HRCTs of patients with middle ear pathologies (cholesteatoma, otosclerosis, and glomus tympanicum) who underwent TEES were obtained. Axial image series were rotated and reformatted -90 or +90 degrees for left and right ear surgeries, respectively, where additional rotation along the left-right axis was performed to align the transcanal series with the plane of the external auditory canal. Quantitative measurements of middle ear structures were recorded. Consecutive transcanal reformatted sections were then reviewed to identify critical middle ear anatomy and pathology with corresponding TEES cases.

RESULTS

The aforementioned methodology was used to create three transcanal view HRCTs. The mean left-right axis degree of rotation was 4.0 ± 2.2 degrees. In the cholesteatoma transcanal HRCT, areas of cholesteatoma involvement in middle ear compartments (e.g. epitympanum) and eroded ossicles were successfully identified in the corresponding case. In the otosclerosis transcanal HRCT, areas for potential otosclerotic involvement were visualized such as the round window as well as a low-hanging facial nerve. In the glomus tympanicum transcanal HRCT, the span of the glomus tympanicum was successfully visualized in addition to a high riding jugular bulb.

CONCLUSION

A transcanal HRCT reformat may aid preoperative planning for middle ear pathologies. This novel reformat may help highlight patient-specific anatomy.

Complete Removal of Stage II Congenital Cholesteatoma Destroying Temporomandibular Joints Using Transcanal Endoscopic Ear Surgery With a Mirror Technique: A Case Report

Transcanal endoscopic ear surgery (TEES) provides wide-angle clear vision for otologic surgery. We report the utility of TEES with the mirror technique for the complete removal of a congenital cholesteatoma in a 3-year-old boy. A white mass was observed through the tympanic membrane, and a congenital cholesteatoma was suspected during the conservative treatment of otitis media with effusion. Pre-operative computed tomography (CT) revealed an irregular mass lesion in the left middle ear, with bone erosion in the hypotympanum. During surgery, an open-type cholesteatoma was observed, mainly in the middle lower tympanum. The cholesteatoma had destroyed the periphery of the temporomandibular joint, which was widely exposed. The cholesteatoma had also spread to the tympanic sinus. Careful observation with a forward-oblique viewing endoscope and a variable angle tympanic mirror enabled complete removal of the mass under endoscopic guidance. No recurrence was observed during the postoperative follow-up, although residual open-type congenital cholesteatoma may often result in recurrence. We believe that careful removal of the lesion under TEES, which allowed us to perform surgery under a secure view with illumination and magnification, may have facilitated complete removal and prevented recurrence.

Otoplasty: a modified Chong-Chet technique with positive long-term results

BACKGROUND

In the last few decades, many techniques have been developed to correct prominent ear deformities. Modified Chong-Chet otoplasty represents a new and improved classical Chong-Chet procedure for prominent ear surgery. This study evaluates and compares the long-term results of standard Chong-Chet otoplasty with the modified technique.

METHODS

A retrospective study was conducted on patients undergoing otoplasty at the Special Hospital S-tetik Banja Luka between January 17, 2017, and February 5, 2019. The total number of patients undergoing the procedure was 129. The first group (48 patients) underwent otoplasty using the Chong-Chet technique, while the second group (81 patients) underwent a modified Chong-Chet procedure. All patients were randomly selected on the condition that the antihelix was absent.The data were processed and analyzed using the Statistical Package for the Social Sciences version 24 using nonparametric tests (χ2 test, Mann-Whitney U test and Kruskal-Wallis test).

RESULTS

Every second patient was satisfied (19 patients were partially satisfied and five patients were completely satisfied) with the results of the classical Chong-Chet technique. Seven patients were neither satisfied nor dissatisfied, while 17 patients were dissatisfied (11 patients were completely dissatisfied and 6 patients were mostly dissatisfied). As for the modified method, on average, nine out of 10 patients (73 or 90.1%) were satisfied, of which 49 patients (60.5%) were completely satisfied and 24 patients (29.6%) were mostly satisfied.The statistical significance was P < .05.Research results point to the modified Chong-Chet technique being a significant improvement to the classical method.

CONCLUSION

Modified Chong-Chet technique increases the number of positive long-term results and significantly improves the standard method.

Subtotal temporal bone resection en bloc with the parotid gland and temporomandibular joint: a 2-dimensional operative video

Primary temporal bone squamous cell carcinoma is sporadic. According to previous studies, margin-negative resection provides the best prognosis (Nakagawa et al., 2006; Moody et al., 2000; Yin et al., 2006; Komune et al., 2021 [1-4]). When tumors extend behind the tympanic membrane, lateral temporal bone resection, which is a well-established procedure, is insufficient to achieve a tumor-free margin. For these cases, subtotal temporal bone resection (STBR) can achieve a complete en bloc resection with a tumor-free margin. Furthermore, STBR en bloc with surrounding structures, including the temporomandibular joint and parotid gland, complicates surgical techniques. We previously reported this surgical procedure in a stepwise manner using cadaveric dissection (Komune et al., 2014 [5]). The STBR en bloc with the parotid gland and temporomandibular joint is composed of three approaches according to our previous report: high cervical exposure (neck dissection), a subtemporal-infratemporal fossa approach, and a retromastoid-paracondylar approach. However, we currently lack demonstrative surgical videos. According to our previous report, this video first demonstrates STBR en bloc with the parotid gland and temporomandibular joint (Komune et al., 2014 [5]). The histopathological diagnosis of a 57-year-old woman suffering from a large tumor protruding from her auricle indicated squamous cell carcinoma; after the diagnosis she was referred to our hospital. Computed tomography revealed the full extent of the tumor, which was about 8 cm in diameter and had damaged the middle cranial base, mastoid bone, and middle ear cavity. Magnetic resonance imaging indicated invasion of the glenoid fossa and parotid gland, equivalent to a Pittsburg stage cT4 tumor. The patient underwent STBR en bloc with the parotid gland and temporomandibular joint. Lower cranial nerves (CN IX-XII) were preserved, and the patient achieved normal oral intake without additional procedures after surgery. At six months post-operation, no recurrence was noted. In this video, we first demonstrate the surgical procedure of the STBR en bloc with the parotid gland and temporomandibular joint for far-advanced temporal bone squamous cell carcinoma, and it can be one of the surgical options to achieve the complete resection without exposure of the tumor. Informed consent was obtained from the patient. The video was reproduced with the written informed consent of the patient. Primary temporal bone squamous cell carcinoma is sporadic. According to previous studies, margin-negative resection provides the best prognosis (Nakagawa et al., 2006; Moody et al., 2000; Yin et al., 2006; Komune et al., 2021 [1-4]). When tumors extend behind the tympanic membrane, lateral temporal bone resection, which is a well-established procedure, is insufficient to achieve a tumor-free margin. For these cases, subtotal temporal bone resection (STBR) can achieve a complete en bloc resection with a tumor-free margin. Furthermore, STBR en bloc with surrounding structures, including the temporomandibular joint and parotid gland, complicates surgical techniques. We previously reported this surgical procedure in a stepwise manner using cadaveric dissection (Komune et al., 2014 [5]). The STBR en bloc with the parotid gland and temporomandibular joint is composed of three approaches according to our previous report: high cervical exposure (neck dissection), a subtemporal-infratemporal fossa approach, and a retromastoid-paracondylar approach. However, we currently lack demonstrative surgical videos. According to our previous report, this video first demonstrates STBR en bloc with the parotid gland and temporomandibular joint (Komune et al., 2014 [5]). The histopathological diagnosis of a 57-year-old woman suffering from a large tumor protruding from her auricle indicated squamous cell carcinoma; after the diagnosis she was referred to our hospital. Computed tomography revealed the full extent of the tumor, which was about 8 cm in diameter and had damaged the middle cranial base, mastoid bone, and middle ear cavity. Magnetic resonance imaging indicated invasion of the glenoid fossa and parotid gland, equivalent to a Pittsburg stage cT4 tumor. The patient underwent STBR en bloc with the parotid gland and temporomandibular joint. Lower cranial nerves (CN IX-XII) were preserved, and the patient achieved normal oral intake without additional procedures after surgery. At six months post-operation, no recurrence was noted. In this video, we first demonstrate the surgical procedure of the STBR en bloc with the parotid gland and temporomandibular joint for far-advanced temporal bone squamous cell carcinoma, and it can be one of the surgical options to achieve the complete resection without exposure of the tumor. Informed consent was obtained from the patient. The video was reproduced with the written informed consent of the patient.

Effects of vestibular neurectomy and neural compensation on head movements in patients undergoing vestibular schwannoma resection

The vestibular system is vital for maintaining balance and stabilizing gaze and vestibular damage causes impaired postural and gaze control. Here we examined the effects of vestibular loss and subsequent compensation on head motion kinematics during voluntary behavior. Head movements were measured in vestibular schwannoma patients before, and then 6 weeks and 6 months after surgical tumor removal, requiring sectioning of the involved vestibular nerve (vestibular neurectomy). Head movements were recorded in six dimensions using a small head-mounted sensor while patients performed the Functional Gait Assessment (FGA). Kinematic measures differed between patients (at all three time points) and normal subjects on several challenging FGA tasks, indicating that vestibular damage (caused by the tumor or neurectomy) alters head movements in a manner that is not normalized by central compensation. Kinematics measured at different time points relative to vestibular neurectomy differed substantially between pre-operative and 6-week post-operative states but changed little between 6-week and > 6-month post-operative states, demonstrating that compensation affecting head kinematics is relatively rapid. Our results indicate that quantifying head kinematics during self-generated gait tasks provides valuable information about vestibular damage and compensation, suggesting that early changes in patient head motion strategy may be maladaptive for long-term vestibular compensation.

Beyond Tympanomastoidectomy: A Review of Less Common Postoperative Temporal Bone CT Findings

Postoperative temporal bone imaging after surgical procedures such as ossiculoplasty, tympanomastoidectomy, cochlear implantation, and vestibular schwannoma resection is often encountered in clinical neuroradiology practice. Less common otologic procedures can present diagnostic dilemmas, particularly if access to prior operative reports is not possible. Lack of familiarity with the less common surgical procedures and expected postoperative changes may render radiologic interpretation challenging. This review illustrates key imaging findings after surgery for Ménière disease, superior semicircular canal dehiscence, temporal encephalocele repairs, internal auditory canal decompression, active middle ear implants, jugular bulb and sigmoid sinus dehiscence repair, and petrous apicectomy.

Endoscopic Management of Pediatric Chronic Ear Disease

Pediatric chronic ear disease and its sequelae often necessitate surgical intervention, such as ear tube insertion, ossiculoplasty, tympanoplasty, and cholesteatoma removal. Although these procedures have traditionally been performed with the microscope, use of rigid endoscopes provides an alternative method for visualization. The endoscope offers improved visualization of the middle ear space and adjacent structures and can either be used alone to perform surgery through the ear canal or together with the microscope if mastoidectomy is required. Endoscopic ear surgery can reduce the need for a postauricular incision or mastoidectomy while resulting in equivalent hearing outcomes compared with those performed with the microscope. In addition, use of the endoscope is associated with lower rates of residual disease following primary cholesteatoma procedures.

Tolerance and safety of 45S5 bioactive glass used in obliteration procedures during middle ear surgery: Preliminary results

OBJECTIVE

Otologists face many disadvantages after extensive mastoid drilling and canal wall down technique in cholesteatoma surgery. Mastoid and epitympanic cavity obliterations or reconstructions after canal wall down procedure using bioactive glass seem to be an interesting solution to overcome some of these disadvantages. Bioactive glass offers many benefits including the availability when there are no sufficient autologous materials for obliteration, its antibacterial activity in chronic infected ear and decreasing the recidivism of cholesteatoma. The objective of this study is to evaluate the tolerance and safety of 45S5 bioactive glass as a filing bone-synthetic material by clinical, audiological and radiological examinations.

METHODOLOGY

A retrospective study of 42 patients who had undergone obliteration of mastoid or/and epitympanic cavity with 45S5 bioactive glass between, November 2017 to January 2019. Data from clinical follow-ups, audiological assessment, CT-scan and MRI were analyzed.

RESULT

The patients' mean age was 49.8 years old. Microscopic examinations showed dry well-healed tympanic membranes and external auditory canals for 95.2% of the patients after 1 year. Inner ear injuries after obliteration were not observed by comparing pre and post-operative bone conduction audiometry (p value 0.457). No facial palsy was reported post-operatively. One-year postoperative radiological assessments did not reveal any silent implantation of cholesteatoma or residual disease.

CONCLUSION

Mastoid and epitympanic obliterations with 45S5 bioactive glass seem to be a tolerable and safe option in cholesteatoma surgery with favorable outcomes similar to other member of bioactive glass especially the S53P4.

Nuances in transcanal endoscopic surgical technique for glomus tympanicum tumors

OBJECTIVE

To describe the utility and nuances of transcanal endoscopic surgery (TCES) on glomus tympanicum tumors from a single surgeon's experience.

PATIENTS/INTERVENTION

Twelve patients, eight female and four males, diagnosed pre-operatively with glomus tympanicum tumors. They all underwent endoscopic resection by a single surgeon.

MAIN OUTCOME MEASURES

Feasibility of endoscopic resection of glomus tympanicum tumors without conversion to a microscopic approach. Secondary outcomes include tumor stage, pre and post-operative audiometry, vertigo, sensorineural hearing loss (SNHL) and integrity of the facial nerve, ossicles, chorda tympani and tympanic membrane.

RESULTS

Twelve patients underwent TCES, eight patient's pathology results were glomus tympanicum, ranging from Glasscock-Jackson grade I-III. Due to loss in follow up, 6/8 patients had complete audiometric data, which were analyzed. Average pre-operative air-bone-gap (ABG) was 5.41 compared to post-operative ABG of 5.08 (p > 0.89). No patients resulted in any, post-operative vertigo, tinnitus, SNHL, facial nerve injury or chorda tympani nerve injury. Two patients had intentional tympanic membrane perforations secondary to tumor adherence to the membrane. They were repaired with tragal perichondrium graft. No patients have had any recurrences.

CONCLUSIONS

Endoscopic resection of glomus tympanicum tumors is a feasible and effective, alternative visualization modality for the neurotologist. Surgical pearls are described herein.

Radiologic evaluation of the mastoid segment of the facial nerve tract in the intact temporal bone

PURPOSE

To localize the facial nerve course in the mastoid segment and to measure its distances relative to the tympanic membrane.

METHODS

This is a cross-sectional descriptive study. During 2019 in a tertiary hospital, 129 non-contrast and non-pathologic temporal CT images were studied in a tertiary hospital. Facial nerve distances were measured from the planes passing through the annulus in the axial cross-sections at superior, umbo, and inferior levels of the tympanic membrane. It was done in two different dimensions which are anteroposterior (toward the plane of the ear canal wall) and mediolateral (toward the plane of the tympanic membrane).

RESULTS

The least mean anteroposterior distance between the facial nerve and the posterior ear canal wall was at the level of umbo (3.66 ± 0.76 mm). The nearest point of the nerve toward the tympanic membrane was the inferior level (- 0.03 ± 0.81 mm). Overall external ear canal lengths were statistically significantly lower in women rather than men. There was a reverse correlation between the age and the ear canal length.

CONCLUSION

Posterior canalplasty seems to be safe unless dissection does not cross the plane of annulus. In this study, the safe margin was 1.4 mm in posterior canal wall drilling. It also should be performed carefully if it extends to the inferior side of the canal. Measuring the mediolateral dimension of the nerve toward the annulus in the axial CT images seems to be practically beneficial, especially in the inferior where the ear canal wall turns and might not act as a good landmark. Paying attention to this plane may reduce the risks of nerve injury in any procedures with transcanal approaches, particularly in inferior canaloplasty.

Optimizing Management of Otophyma: A Case Series Highlighting the Role of Surgical and Retinoid Therapy

Otophyma is a rare condition that can result in conductive hearing loss. Current otophyma literature does not examine validated treatment outcomes for patients. Utilizing a medical and surgical approach to maintain a patent canal can lead to significant objective improvements. The aim of this case series is to describe a combined successful approach in 3 cases from an academic, multidisciplinary center. The main outcomes analyzed were pre and post air-bone gap audiogram analysis and disimpaction frequency. The results showed that post-management, patient 1 had substantial improvement in hearing, recovering 49 dB in his right ear and 25 dB in his left ear, demonstrating near complete air-bone gap closure. Patient 2 showed a similar dermatologic and functional improvement, although objective audiometric assessment related to otophyma could not be performed due to coexisting chronic otitis media and cholesteatoma. Patient 3, in the 12 months prior to comanagement, had 8 bilateral disimpactions, and following comanagement had 2 disimpactions in 23 months. All 3 patients were pleased with the resultant functional and physical appearance following comanagement. By presenting this approach and objective measures of treatment, we hope to improve future clinical decision-making in a rare condition.

Minimization of skin incision at preauricular sinusectomy using a trans pit approach

BACKGROUND

We introduced a surgical procedure which includes a simple sinusectomy without opening the sinus whilst attempting to minimize the skin incision.

METHODS

A total of 34 patients with preauricular sinus were treated. In six patients, this technique was performed bilaterally, so a total of 40 ears were enrolled and analyzed for recurrence rate and surgical outcome in retrospective observational study. A database was created which included patient age, the preoperative and postoperative incision size, suture materials used, and complications. Incisional size according to the previous infection condition and incision and drainage (I & D) history were analyzed.

RESULTS

The mean initial skin incision length was 0.75 ± 0.40 cm and mean incision length after skin suture was 0.81 ± 0.42 cm. The young group under 10 years of age had a mean initial skin incision length of 0.56 ± 0.06 cm, and mean incision length after skin suture was 0.58 ± 0.08 cm. Suture materials were Nylon 6-0 for 14 ears, Nylon 7-0 for 20 ears, and Nylon 8-0 for 6 ears. The incidence of minor complications (immediate wound dehiscence, wound opening at a previous I & D region, keloid formation) was 7.5%.

CONCLUSION

Our method overcomes potential problems with esthetics in addition to reducing the recurrence rates of preauricular sinusectomy. With our technique, minimization of skin incision length is possible without the risk of recurrence. The use of fine suture materials and not using drainage avoids additional skin trauma.

Grading of the Position of the Mastoid Tegmen in Human Temporal Bones - A Surgeon's Perspective

OBJECTIVES

To establish a new surgically relevant classification system of the anatomic variations of the temporal bone tegmen plate as well as to perform a comparative analysis, with respect to the pneumatization patterns in the cadaveric temporal bones.

MATERIALS AND METHODS

Microdissection of the human cadaveric temporal bones was performed after obtaining ethical approval from the Institutional Ethical Committee (F.8-522/A-522/2017/RS). The pneumatization pattern of the temporal bones was noted as "under-pneumatized" or "well-pneumatized." The tegmen mastoid (TM) was classified into two grades as per the position of the tegmen plate and the visibility of the superior semicircular canal (SSCC) and the aditus. The latter two structures were well visualized in Grade A and poorly visualized in Grade B. The data were analyzed using Stata 14.0 (Stata Corp, 4905, Lakway drive, College Station, Texas, USA).

RESULTS

Ninety-three temporal bones were dissected under microscope. Fifty-eight bones were well-pneumatized and 35 were under-pneumatized. The tegmen plates were classified as Grade-A in 49 bones (well-pneumatized -37 and under-pneumatized -12), and as Grade-B in 44 bones (well-pneumatized-21, poorly-pneumatized-23). Grade-A classification was significantly more common in well-pneumatized temporal bones, while Grade-B was more common in under-pneumatized bones (p=0.0057).

CONCLUSION

We propose a surgically relevant classification for TM positioning. A well-pneumatized temporal bone is associated with a significantly higher position of the tegmen plate (Grade-A TM).

Combined surgical approach to intralabyrinthine schwannoma

INTRODUCTION

Intralabyrinthine schwannoma (ILS) is a tumor originating from the Schwann cells in the inner ear. Various surgical approaches can be used for the resection of ILS. The aim of this report is to describe a case involving a 60-year-old man who was treated successfully with a combined surgical approach.

CASE REPORT

The patient underwent a combined microscopic (transmastoid labyrinthectomy) and endoscopic procedure for surgical excision of ILS involving the vestibule and the lower half of the cochlear basal turn. The combined surgical technique enabled a complete removal of the ILS without removal of the unaffected cochlea as well as the external auditory canal. Besides additional exclusion of the middle ear, blind-sac closure of the external auditory canal and cavity obliteration were avoided. No postoperative complications were observed.

DISCUSSION

A combined microscopic and endoscopic approach to surgery enables removal of the ILS involving the vestibule and the lower half of the cochlear basal turn while helping to reduce surgical radicality.

Audiologic prognostic factors for hearing preservation following vestibular schwannoma surgery

BACKGROUND

Postoperative hearing loss after vestibular schwannoma (VS) removal still remains a lifelong problem for the patients. The present study analyzes the problem of hearing preservation after VS removal from a different angle than available professional literature on this topic.

OBJECTIVES

To identify audiologic factors which determine the extent of hearing loss in patients operated on for VS.

MATERIAL AND METHODS

The study group included 86 patients operated on due to VS accessed via the middle cranial fossa. The analyses involved the effect on absolute hearing loss, which was calculated on the basis of the results of pure-tone audiometry performed preand postoperatively, and factors included in the preoperative audiologic tests, such as pure-tone audiometry, speech audiometry, auditory brainstem response (ABR), and impedance audiometry.

RESULTS

The following parameters were demonstrated to have a prognostic value: 1. hearing thresholds at 125 Hz, 500 Hz and 1,000 Hz for the operated ear, Pure Tone Average (PTA) - calculated specifically at 500 Hz, 1,000 Hz and 2,000 Hz and at 500 Hz, 1,000 Hz, 2,000 Hz, and 4,000 Hz for the operated ear, and normal audiometric curve; 2. speech discrimination ranging from 55 dB to 75 dB for the operated ear, speech detection threshold (SDT) in the operated ear and interaural difference at 25-35 dB (non-operated vs operated ear); 3. presence of wave V, the values of I-V and III-V intervals for the operated ear, the amplitude of wave V, and the interaural ratio of wave V amplitudes; 4. intensity level for obtaining stapedial reflex or an abnormal reflex at Ipsi 500 Hz, 1,000 Hz and 2,000 Hz, and Contra 500 Hz, 1,000 Hz, 2,000 Hz, and 4,000 Hz.

CONCLUSIONS

The better the preoperative hearing status, the more substantial surgery-related hearing loss was observed. A number of preoperative parameters of the basic diagnostic set of audiologic tests present a prognostic value for the degree of surgery-related hearing loss in VS patients.

Stapes hypermobility as a possible cause of hyperacusis

OBJECTIVE

Hyperacusis is a reduction of normal tolerances for everyday sounds. Although several publications have been produced demonstrating that minimally invasive surgical procedures may improve patient symptoms, the precise etiology of hyperacusis often remains elusive. This study describes 21 patients, 7 of whom stapes hypermobility is believed to be a mechanical genesis of their hyperacusis symptoms.

STUDY DESIGN

A prospective, repeated-measure single-arm design was used for this study.

SETTING

All patients were evaluated and treated at a tertiary level otologic referral center.

SUBJECTS AND METHODS

21 patients (Cohort A) with severe hyperacusis underwent oval and round window reinforcement. Seven patients (Cohort B) intraoperatively appeared to have subjective hypermobility of the stapes. Additional reinforcement of the stapes superstructure was performed in these patients.

RESULTS

In Cohort A, loudness discomfort level (LDL) values improved on average from 72.7 dB to 81.9 dB. Hyperacusis questionnaire (HQ) scores improved from 30.1 to 14.7. Numeric Rating Scale scores (0-10) decreased from 8.5 to 4.0. In Cohort B, values similarly improved from an average of 72.4 dB to 88.2 dB. HQ scores improved from 35.8 to 18.9. Numeric Rating Scale scores fell from 10.0 to 3.7. Postoperatively there were no complaints of hearing loss. Sixteen out of 21(76%) reported improved quality of life and diminished symptoms of hyperacusis.

CONCLUSION

It is possible that patients suffering from hyperacusis may have a mechanical cause for their symptoms. Further research is necessary to clarify stapes mobility in patients with these symptoms. Excess temporalis tissue reinforcement of the stapes along with round window reinforcement shows promise as a minimally invasive surgical option for patients suffering from hyperacusis.

Surgical management of patients with Eagle syndrome

OBJECTIVE

Eagle syndrome, a spectrum of disease resulting from an elongated styloid process and/or calcified stylohyoid ligament, lacks standardized recommendations regarding indications for surgical intervention and approach.

STUDY DESIGN

Retrospective cohort study.

SETTING

Single tertiary care institution.

SUBJECTS

Patients treated surgically for Eagle syndrome between January 2011 and June 2017.

METHODS

Patients were diagnosed with Eagle syndrome based on thorough clinical workup and assessment. The primary outcome was improvement in pain severity following surgery, with complete resolution of pain being considered clinically meaningful. Wilcoxon rank-sum tests and Fisher's exact were used to compare numerical and categorical variables, respectively.

RESULTS

Twenty-one patients were diagnosed with Eagle syndrome and underwent surgical resection of the styloid process. Patients most often complained of neck pain (81%), throat pain (62%), and ear pain (48%). Among these patients, 57% of procedures featured a transcervical approach, while the remaining 43% were transoral. The vast majority (90%) of patients experienced improvement in pain severity from a median of 6.0 before surgery to 0.0 afterwards (p < 0.01) as 62% experienced complete resolution. Using multivariable linear regression to model changes in pain severity, neck pain (β = -1.69, p < 0.01) and jaw pain (β = -0.93, p = 0.03) predicted greater relief, while headache (β = 0.82, p = 0.04) predicted an inferior response. Adverse events were uncommon and typically resolved within three months, with 24% experiencing first bite syndrome and 19% reporting numbness.

CONCLUSIONS

Transcervical and transoral styloidectomy are effective treatments for Eagle syndrome with minimal adverse effects. Patients with classic symptoms of neck or jaw pain benefit most from surgery.

Perioperative Care of the Patient With Acoustic Neuroma

Acoustic neuromas, also known as vestibular schwannomas, are slow-growing, benign tumors that develop on the eighth cranial nerve. Common signs and symptoms of an acoustic neuroma include hearing loss and balance disturbances. A physical examination, a hearing evaluation, and diagnostic imaging assist in the diagnosis of an acoustic neuroma. Patients with a confirmed tumor have three treatment options: observation, stereotactic radiosurgery, and surgical removal. Complications include cerebrospinal fluid leakage, damage to ancillary brain structures, facial nerve damage, and bleeding or vascular injury. This article focuses on the surgical removal of an acoustic neuroma and the role of the perioperative nurse in the perioperative care of the patient.

Middle cranial fossa approach for the repair of superior semicircular canal dehiscence is associated with greater symptom resolution compared to transmastoid approach

BACKGROUND

Superior semicircular canal dehiscence (SSCD) is a disorder of the skull base that is gaining increasing recognition among neurosurgeons. Traditionally, the middle cranial fossa (MCF) approach has been used for the surgical repair of SSCD. However, the transmastoid (TM) approach is an alternative strategy that has demonstrated promising results.

METHODS

We performed independent searches of a popular database to identify studies that described outcomes following the surgical repair of SSCD through MCF and TM approaches. The primary outcome was symptom resolution.

RESULTS

Our analysis included 24 studies that described 230 patients that underwent either an MCF (n = 148, 64%) approach or a TM (n = 82, 36%) approach for primary surgical repair of SSCD. A greater percentage of patients in the MCF group experienced resolution of auditory symptoms (72% vs 59%, p = 0.012), aural fullness (83% vs 55%, p = 0.049), hearing loss (57% vs 31%, p = 0.026), and disequilibrium (75% vs 44%, p = 0.001) when compared to the TM group. The MCF approach was also associated with higher odds of symptom resolution for auditory symptoms (odds ratio [OR] 1.79, 95% confidence interval [CI] 1.14-2.82), aural fullness (OR 4.02, 95% CI 1.04-15.53), hearing loss (OR 2.91, 95% CI 1.14-7.42), and disequilibrium (OR 3.94, 95% CI 1.78-8.73). The mean follow-up was 9 months.

CONCLUSIONS

The literature suggests that the MCF approach for the repair of SSCD is associated with greater symptom resolution when compared to the TM approach. This information could help facilitate patient discussions.

Imaging Evaluation of the Location and Fenestration of Sellar Floor During Endonasal Transsphenoidal Surgery in Patients with Pituitary Adenomas

OBJECTIVE

To evaluate clinical value of three-dimensional (3D) computed tomography (CT) reconstruction of the sphenoid sinus separation in localizing sellar floor during endonasal transsphenoidal surgery and determine size and location of sellar floor fenestration.

METHODS

There were 51 patients eligible for study inclusion. Preoperative CT scan of the paranasal sinus and CT scan and magnetic resonance imaging of the pituitary gland were obtained. Sphenoid sinus separation was reconstructed using Mimics 15.0 software, and quantity, shape, and orientation were observed and compared with intraoperative data to guide the localization of sellar floor. Anatomic variation of the sphenoid sinus and adjacent structures, tumor and sella turcica morphology, minimal distance between the cavernous segment of the internal carotid artery bilaterally, and shortest distance from the midline were measured.

RESULTS

Based on the shape of the sphenoid sinus separation, sellar floor was accurately localized in all cases. Intraoperative sphenoid sinus separation was consistent with preoperative three-dimensional CT reconstruction images. The sellar floor was extremely small in 2 patients, and insufficient fenestration of sellar floor negatively affected tumor resection. Preoperative three-dimensional CT reconstruction is helpful for accurate and rapid localization of sellar floor.

CONCLUSIONS

Anatomic variation of sphenoid sinus and adjacent structures, characteristics of tumor and sella, minimum distance between bilateral cavernous segment of the internal carotid artery, and shortest distance from midline are helpful for establishment of individualized sellar floor fenestration.

Acquisition of surgical skills for endoscopic ear and lateral skull base surgery: a staged training programme

SUMMARY

Endoscopic ear surgery is radically changing the treatment of several middle and inner ear pathology, but its learning presents well-known manual and technical difficulties. The aim of this paper is be to present a training programme based on a modular model of increased difficulties. The experience from 2007 to 2016 at the University Hospital of Modena and University Hospital of Verona was reviewed and analysed for further considerations and to establish stages of training. The increasing experience of expert surgeons who deal with this kind of surgery represented the main guide to establish the steps and progression of training. In addition, the potential risk of damage of vascular structures or nerves represents fundamental criteria for progression toward higher levels. Some not-mandatory skills were also suggested for stage of difficulty. Five stages of training were deemed appropriate for progressive learning of endoscopic ear and lateral skull base surgery, ranging from simple middle and external ear procedures to surgery of inner ear and internal auditory canal. Mastering of each level is suggested before attempting procedures at a higher level, in particular for procedures involving lateral skull base. Standardisation and adoption of modular incremental training are expected to facilitate improvement of otolaryngologists and neurosurgeons starting with endoscopic middle ear and lateral skull base surgery. Adherence to such a programme during the growth phase may potentially decrease the rate of complications, making the training programme safer.

Microsurgery for patients diagnosed with neurofibromatosis type 2 complicated by vestibular schwannomas: Clinical experience and strategy for treatments

Most patients diagnosed with neurofibromatosis type 2 (NF2) have bilateral vestibular schwannomas (VS). Through reviewing surgical method and clinical outcomes, we tried to find out a strategy for treatments in NF2 patients with VS.We retrospectively reviewed patients diagnosed pathological NF2 and have had microsurgery (MS) for VS in the PLA Army General Hospital. Seventeen patients were included from January 2000 to December 2016. Fifteen patients had progressive hearing impairment, and 7 ears were totally deaf. Computed tomography and magnetic resonance imaging were used for preoperative and postoperative evaluation. House-Brackmann (H-B) classification was used to evaluate facial function, and the hearing outcome was classified according to American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) hearing classification system. The outcomes included functional hearing, facial function, and complications.In the 17 patients, 9 were men, and the mean age was 27.2 years old. The mean duration of disease was 38.4 months. Twenty-six VS were excised. Nine patients with bilateral VS and unilateral surgery had repeated surgery for the contralateral tumor after 3 to 12 months. The hearing preservation rate was 41.6%. In the 26 excisions for VS, 24 had intact facial nerve. In the other 2 tumor excision, damaged facial nerves had head-to-head adhesion using biological fibrin glue. The rate of facial nerve function preservation was 60%. No mortality or major complication was reported. The follow-up time ranged from 11 to 78 months with a mean value of 39 months.MS is an effective treatment for NF2 patients with VS. The operation for bilateral VS should be staged according to tumor size and bilateral hearing function. However, methods on how to preserve functional hearing and facial function remain the issue. Further randomized controlled studies are needed to find out a better treatment for NF2 patients with VS according to the overall condition.

Planning nonlinear access paths for temporal bone surgery

PURPOSE

Interventions at the otobasis operate in the narrow region of the temporal bone where several highly sensitive organs define obstacles with minimal clearance for surgical instruments. Nonlinear trajectories for potential minimally invasive interventions can provide larger distances to risk structures and optimized orientations of surgical instruments, thus improving clinical outcomes when compared to existing linear approaches. In this paper, we present fast and accurate planning methods for such nonlinear access paths.

METHODS

We define a specific motion planning problem in [Formula: see text] with notable constraints in computation time and goal pose that reflect the requirements of temporal bone surgery. We then present [Formula: see text]-RRT-Connect: two suitable motion planners based on bidirectional Rapidly exploring Random Tree (RRT) to solve this problem efficiently.

RESULTS

The benefits of [Formula: see text]-RRT-Connect are demonstrated on real CT data of patients. Their general performance is shown on a large set of realistic synthetic anatomies. We also show that these new algorithms outperform state-of-the-art methods based on circular arcs or Bézier-Splines when applied to this specific problem.

CONCLUSION

With this work, we demonstrate that preoperative and intra-operative planning of nonlinear access paths is possible for minimally invasive surgeries at the otobasis.

Effectiveness of Transmastoid Plugging for Semicircular Canal Dehiscence Syndrome

Objectives (1) Evaluate changes in subjective symptoms in patients following transmastoid canal plugging for superior semicircular canal dehiscence (SSCD) syndrome. (2) Quantify changes in hearing in patients who have undergone transmastoid canal plugging for SSCD syndrome. Study Design Case series with chart review. Setting Single tertiary care institution. Subjects and Methods We retrospectively reviewed patients with SSCD who underwent repair with canal plugging via a transmastoid approach between January 2012 and January 2017. Symptom severity was assessed prospectively (autophony, sound/pressure-induced vertigo, disequilibrium, aural fullness, and pulsatile tinnitus) and after surgery. Pure-tone and speech audiometry were measured before and after surgery. Two-sided Wilcoxon rank-sum tests were used to evaluate changes in subjective symptoms and audiometric outcomes. Results Seventeen patients (19 ears) met inclusion criteria. The superior canal was successfully plugged via the transmastoid approach in all cases. Patients reported a statistically significant improvement in autophony, vertigo, aural fullness, and pulsatile tinnitus ( P < .01), without significant improvement in disequilibrium rating ( P = .06). There were no changes noted in pure-tone average or word recognition score; however, there was a statistically significant improvement in air-bone gap at 250 Hz of 10.9 dB ( P = .04) with 12.9-dB improvement in air conduction thresholds ( P = .02) and no difference (0.9 dB, P = .9) in bone conduction thresholds. Conclusion In our study, patients with SSCD demonstrated excellent hearing outcomes and resolution of most otologic symptoms after surgical repair. Transmastoid canal plugging, which has been described to date only in smaller case series, is a safe and effective alternative to the traditional middle cranial fossa approach.

The transotic approach for vestibular schwannoma: indications and results

To analyze retrospectively the indications and the results obtained with the transotic approach in a series of patients with vestibular schwannoma. The study included 36 patients from 2007 to 2013 with a vestibular schwannoma that was removed with a transotic approach. All patients underwent preoperative pure tone audiometry, evaluation of facial function and CT and MR imaging. All patients having (1) a hearing loss of more than 50 dB, (2) an average tumor size of 2.7 cm (range 0.5–5.0 cm) and (3) signs of a contracted mastoid (high jugular bulb, anteriorly located sigmoid sinus, low middle cranial fossa, or reduced pneumatization) were selected. The tumor was totally removed in 34 and near-totally removed in 2 patients. The facial nerve was preserved in all patients. The postoperative facial function after 6 weeks was House–Brackmann grade I in 7, grade II in 27, and grade III in 2 patients. All patients presented postoperatively with unilateral total deafness. Seven patients experienced transitory postoperative imbalance. There were two patients who required revision surgery, one with intracranial hemorrhage and another with a CSF leak. There were no deaths and no severe complications such as hemiplegia or intracranial infections. The transotic approach has proven to be of value for the removal of vestibular schwannomas up to 5.0 cm in the presence of temporal bone contraction. Hearing was not preserved; however, other clinical outcomes were very favorable, including high rates of total tumor removal and facial nerve preservation, and low rates of complications.

The Existence of a Natural Plica at the Anatomical Base of the Antihelix and its Surgical Importance to Address Protruding Ears: An Anatomicosurgical Study

BACKGROUND

Protruding ears represent the main abnormality of the external ear, which has required numerous anatomic and surgical studies. Most studies give attention to the absence of the antihelix as the anatomic defect responsible for the clinical deformity of the lateral aspect of the ear that leads to its anteversion. The reason for this study is the controversial origin of the fold of the antihelix within the auricle framework, a field of interest for aesthetic otoplasty. The current study examined the medial surface of the cartilaginous ear frame from cadaver specimens with right morphology to investigate the starting point of the fold of the antihelix. This allowed for verification of a natural plica at the anatomic base of this antihelical fold, which to date has not had its topography described morphologically. It is acknowledged that relevant literature makes no reference to this innominate natural plica at the origin of the antihelix, whose anatomic and surgical importance is related in this report. This study aimed to show that the existence of a natural plica at the base of the antihelix in ear framing represents a landmark between normal and protruding ear morphology.

METHODS

For 8 years, 118 ears were carefully investigated within rigid ethical principles based on a thorough review of the pertinent literature. The study investigated 16 selected cadaver specimens and 102 protruding ears dissected by the senior author including 49 bilateral cases (26 males and 23 females) and 4 unilateral cases (2 males and 2 females). Bifacial anthropometric measurements by calipers were used for documentation.

RESULTS

A natural plica at the base of the antihelix was found in all cadaver ears selected with right morphology, whereas it was totally absent in every surgically treated protruding ear irrespective of color, gender, age, or ethnic origin. Ambilateral measures of the antihelix eminence certify the study object in normal specimens as well as its lack in abnormal ones.

CONCLUSION

Technical and topographic knowledge that a natural plica exists at the anatomic base of the antihelix is a valuable key point in recognizing the normal external ear. In addition, the making of a natural plica is the first and most effective factor in the reconstruction of the antihelical fold and its absolute absence results in the pathologic condition for protruding ears.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the A3 online Instructions to Authors. http://www.springer.com/00266 .

Cadaveric Testing of Robot-Assisted Access to the Internal Auditory Canal for Vestibular Schwannoma Removal

HYPOTHESIS

An image-guided robotic system can safely perform the bulk removal of bone during the translabyrinthine approach to vestibular schwannoma (VS).

BACKGROUND

The translabyrinthine approach to VS removal involves extensive manual milling in the temporal bone to gain access to the internal auditory canal (IAC) for tumor resection. This bone removal is time consuming and challenging due to the presence of vital anatomy (e.g., facial nerve) embedded within the temporal bone. A robotic system can use preoperative imaging and segmentations to guide a surgical drill to remove a prescribed volume of bone, thereby preserving the surgeon for the more delicate work of opening the IAC and resecting the tumor.

METHODS

Fresh human cadaver heads were used in the experiments. For each trial, the desired bone resection volume was planned on a preoperative computed tomography (CT) image, the steps in the proposed clinical workflow were undertaken, and the robot was programmed to mill the specified volume. A postoperative CT scan was acquired for evaluation of the accuracy of the milled cavity and examination of vital anatomy.

RESULTS

In all experimental trials, the facial nerve and chorda tympani were preserved. The root mean squared surface accuracy of the milled cavities ranged from 0.23 to 0.65 mm and the milling time ranged from 32.7 to 57.0 minute.

CONCLUSION

This work shows feasibility of using a robot-assisted approach for VS removal surgery. Further testing and system improvements are necessary to enable clinical translation of this technology.

[The endoscopic anatomy of the middle ear (a dissection study)]

The objective of the present work was to study the specific endoscopic anatomical features of the middle ear using the dissected temporal bones with the intact tympanic membrane. The 18 cm long endoscopes 4 mm in diameter with a visual angle from 0 to 45 degrees in the combination with some other microinstruments, such as ear pincers, needles, curettes, elevators, and suction tubes, were used during the examination. It was shown that endomeato-transtympanic endosopy provides a panoramic view of almost all structures of the middle ear. After the resection of the posterior bone edge of 'annulus tympanicus', the use of the 45o endoscope ensured the panoramic view not only of certain structures of the middle ear (e.g. the tympanic chord, the stapedius muscle tendon, the entire pyramidal process) but also of the structures of the retrotympanic and anterior epitympanic spaces.

Hearing aid silicone impression material as a foreign body in the middle ear

We report an extremely rare case of hearing aid silicone impression material as a foreign body in the middle ear. Symptoms of the patient were otorrhea and vertigo after taking of a mold impression on his only hearing ear, and the symptoms mimicked chronic otitis media. A temporal bone CT scan revealed foreign body material in the middle ear and Eustachian tube. An intact canal wall mastoidectomy with a facial recess approach and type IV tympanoplasty was performed to remove the silicone impression material. In addition to the case report, we review the literature regarding impression material foreign bodies.

A blue middle ear mass: Cholesterol granuloma mimicking a glomus tumor and endolymphatic sac tumor

Cholesterol granuloma (CG) is the most common benign lesion of the petrous apex, however, it can grow significantly large and become destructive causing a diagnostic dilemma. This case presents a 25-year-old female with 2-year history of left-sided progressive and profound hearing loss, a transient left-sided facial paralysis and cranial nerve 10 palsy who presented with a blue middle ear mass. Her diagnosis did not become apparent until direct visualization intraoperatively. The objective of this case study is to highlight the destructive capabilities of CG and the importance to keep it in the differential diagnosis of a large, erosive, expansile skull base lesion in order to avoid overly aggressive resection or other unnecessary treatment.

Acute bacterial meningitis caused by acute otitis media in adults: A series of 12 patients

We conducted a retrospective chart review to characterize the outcomes of 12 patients-9 men and 3 women, aged 21 to 79 years (mean: 49)-who had been treated at our tertiary care center for acute bacterial meningitis caused by acute otitis media (ABMAO). Fever was the most common presenting sign/symptom, observed in 8 patients, followed by otalgia, neck stiffness, headache, and confusion. An opaque and bulging tympanic membrane was observed in 8 patients. Cultures were positive for Streptococcus pneumoniae in the cerebrospinal fluid, ear, and blood in 7, 5, and 3 patients, respectively. Immediate treatment included tympanocentesis, with aspirates sent for bacteriologic cultures. Seven patients (58.3%) underwent surgery; 5 were operated on early, and 2 underwent surgery at a later stage because of a suspected defect in the mastoid bone. A cortical mastoidectomy was performed in 6 of the 7 surgical patients; the remaining patient underwent a canal-wall-down procedure. Ten patients experienced a full recovery, 1 died, and 1 had a poor neurologic outcome (vegetative state); both of the latter 2 patients were older than 60 years. We conclude that early diagnosis, administration of antibiotics, and myringotomy are crucial for control of ABMAO. A cortical mastoidectomy with ventilation tube insertion can be reserved for patients who do not respond, which is common.

Residual cholesteatoma revealed by endoscopy after microsurgery

Residual cholesteatoma revealed by endoscopy after microsurgery.

OBJECTIVE

To endoscopically examine common sites of residual cholesteatoma occurrence after microscopic ear surgery.

METHODS

Thirty patients (15 men and 15 women; age range: 7-81 years) who underwent treatment for middle ear cholesteatoma (20 patients with pars flaccida :holesteatoma and 10 patients with pars tensa cholesteatoma) were selected. Following the removal of the cholesteatoma matrix via microscopy, residual matrix presence was assessed using an endoscope system. Additional resection was performed if the residual matrix was detected. Sites of residual matrix and their rates of incidence were then investigated.

RESULTS

Residual matrix was observed in nine out of the 30 (30%) patients by endoscopy after microscopic surgery. Residual matrix was observed in eight out of the 20 (40%) patients with pars flaccida cholesteatoma and in one out of :he 10 (10%) patients with pars tensa cholesteatoma. Residual matrix was observed in six out of the 14 (43%) patients who underwent canal wall up (CWU) tympanomastoidectomy and in three out of the 13 (23%) patients who underwent -anal wall down (CWD) tympanomastoidectomy. Sites of residual matrix included the tegmen tympani in two patients, he medial scutal surface in three patients, the tympanic sinus in two patients and the anterior epitympanic recess in three patients. The risk of residual matrix was greater in patients with pars flaccida cholesteatoma than in those with pars tensa :holesteatoma. The attic, tympanic sinus and anterior epitympanic recess are common sites of residual cholesteatoma.

CONCLUSION

Endoscopy is advantageous for the assessment of residual cholesteatoma in hidden areas.

Consolidative Technique Otoplasty: Comprehensive Approach in Combining Techniques

BACKGROUND

This study aimed to present the long-term results of the consolidative technique otoplasty (CTO).

METHODS

Patient age, sex, duration of follow-up, and how the deformity (bilateral-unilateral) occurred were determined. The kind of anesthesia, duration of surgery, surgical techniques used during the operation were reported, and the preoperative and postoperative distances between the ear and head were measured at four points (SUP: The highest point of the helix; SCA: the concha superior sticking points; ICA: stick point of Concha at the inferior; and lobular). Early- and late-term complications were recorded in the postoperative period.

RESULTS

A total of 63 (21M-42FM) patients whose average age of 21:41 ± 8.96 (7-41), 119 ears (Right: 58/Left: 61) were operated on with this technique between 2013 and 2015. Mean follow-up was 18:22 ± 9:42 months. Anterior scoring was performed for three patients; concha resection was performed in 17 patients. Fifty-five patients were operated on as primary otoplasties and eight were secondary otoplasties. When the preoperative and postoperative SUP, SCA, ICA, and lobule measurements for both ears were compared, the postoperative values were found to be significantly decreased (p < 0.001).

CONCLUSIONS

This technique may be an alternative in the repairs of prominent ears, and it provides an intervention opportunity for all the anatomical structures.

LEVEL OF EVIDENCE V

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