Cochlear Implantation in Neurofibromatosis Type 2-Related Schwannomatosis: Long-Term Hearing Outcomes.

OBJECTIVE: To evaluate long-term hearing outcomes following cochlear implantation in patients with neurofibromatosis type 2 and ipsilateral vestibular schwannoma. STUDY DESIGN: Retrospective study. SETTING: Tertiary general hospital. METHODS: Twenty-two patients undergoing cochlear implantation between 2004 and 2018 with at least 1 year of follow-up were included. Patients were categorized as "users" or "nonusers" of their cochlear implant (CI). For users, speech perception (disyllabic words) without lip-reading was assessed in quiet conditions 1-year postimplantation, and annually thereafter. CI users were classified into 2 groups on the basis of speech intelligibility (≥40% or <40%). Demographic data, treatment options, and tumor size were also recorded. RESULTS: One year after implantation, 16 (73%) patients used their CI daily. Twelve of these patients had a speech intelligibility ≥40% (mean: 74 ± 21.9%). Three had a Koos stage IV tumor. At the last visit (mean duration of follow-up: 6 ± 5 years), 12 of these 16 patients were still using their implant daily, and 6 had a speech intelligibility ≥40%. No predictive factors for good performance at 1 year or performance stability were identified. CONCLUSION: Neurofibromatosis type 2 is a complex disease profoundly affecting patient quality of life, and cochlear implantation should always be considered on a case-by-case basis. In some individuals, cochlear implantation can provide good speech intelligibility for extended periods, even posttreatment or in cases of large tumors.

Exploring Trauma Patterns and Contributing Factors With Slim Straight Electrode Array After Cochlear Implantation.

OBJECTIVE: To assess trauma patterns associated with the insertion of lateral wall electrode arrays. The study focused on 3 categories-scala tympani (ST), intermediate, and scala vestibuli (SV)-to identify traumatic patterns and contributing factors. STUDY DESIGN: Retrospective study. SETTING: Data from 106 cochlear implant recipients at a tertiary otologic center. METHODS: Demographic and surgical data were collected from recipients who underwent cochlear implantation manually and with RobOtol®. Measurements included cochlear dimensions, angular depth of insertion, and position of the first electrode. Three-dimensional reconstructions were used to analyze the electrode array location relative to the basilar membrane, categorized into ST, intermediate, and SV electrodes. Nontraumatic insertion was defined as all electrodes in the ST, while traumatic insertions had 1 or more electrodes in intermediate or SV locations. RESULTS: Out of 106 cases, 44% had nontraumatic and 56% had traumatic insertions. Demographic and surgical characteristics showed no association with traumatic insertions. A deeper position of the first electrode, relative to the round window, was associated with traumatic insertions (P = .03). Three trauma patterns were observed: distal (facing the apical electrodes), proximal (facing the middle electrodes around 180°), and distal/proximal. CONCLUSION: This study considers the intermediate position which could be associated with basilar membrane lesions. Risk zones for intracochlear trauma with lateral wall arrays were identified distally and proximally. Traumatic insertions were independently linked to deeper array placement. Future studies should explore whether gentler insertion, without insisting on further electrode array insertion depth, could reduce the trauma during cochlear implantation.

Long-term clinical and radiological results for fat graft obliteration in subtotal petrosectomy and cochlear implant surgery: a retrospective clinical study.

PURPOSE: The study aimed to evaluate the long-term clinical, radiological, and functional results for subtotal petrosectomy and cochlear implant surgery with closure of the external auditory canal and fat obliteration. METHODS: We retrospectively included all consecutive cases of simultaneous subtotal petrosectomy and cochlear implant surgery performed at a tertiary referral center between 2009 and 2016 using the same surgical technique. All patients underwent postoperative high-resolution computed tomography (HRCT) and annual audiological assessments. A 5-year minimum clinical, radiological, and audiological follow-up was performed. The early and late postoperative results were compared. The main outcome measures were complications, postauricular retraction, fat graft reabsorption, and audiological outcomes. RESULTS: Twenty-nine procedures performed in 23 patients (six bilateral) met the inclusion criteria. The mean age of the patients was 67 ± 13.4 years and mean follow-up duration was 7.5 ± 2 years. At follow-up, postauricular retraction was detected in 24 cases (82.8%), including five cases (17.1%) with subcutaneous protrusion of implant and array. Fat graft volume was significantly reduced at late-HRCT in terms of maximum diameter (2.24 ± 1.0 cm vs 3.69 ± 0.7 cm; p < 0.0005) and surface area (1.88 ± 1.2 vs 4.24 ± 1.6 cm2, p < 0.0005). Six patients had extracochlear electrodes at late-HRCT (3/6 had an increased number of extracochlear electrodes), with a lowering of this group's performance of - 15% (p < 0.005) in the follow-up speech comprehension test. CONCLUSIONS: Subtotal petrosectomy with cochlear implantation is an effective long-term technique in selected cases. Fat grafts showed significant reabsorption at long-term follow-up with reaeration of the middle ear spaces. Prolonged clinical and radiological follow-up is recommended for monitoring implant performances and late complications.

Spontaneous shrinkage of sporadic vestibular schwannomas: a clinical and radiological analysis.

OBJECTIVE: The natural history of sporadic vestibular schwannoma (VS) is unpredictable, as tumors may or may not grow and can even spontaneously regress. A spontaneous VS shrinkage MRI-based pattern has been proposed with either a scalloped tumor aspect in the cerebellopontine angle or the appearance of a CSF-filled space surrounding the intracanalicular (IC) tumor within an enlarged canal. The authors of this retrospective study aimed to describe the evolution of sporadic VSs with radiological signs of VS regression and to identify prognostic factors for tumor shrinkage. METHODS: All MRI scans obtained during patient follow-up were reviewed for extracanalicular (EC) and IC size and tumor characteristics. Volumetric measurements were performed on the first and last MRI scans. Shrinkage was considered to have occurred if the tumor size had decreased by ≥ 2 mm in its largest diameter and/or if the volume had decreased by ≥ 20%. Audiometric data were also collected. RESULTS: Among 512 patients under observation for sporadic VSs, 66 (13%) had at least one radiological sign of VS regression and 31 of these (6% overall) had confirmed tumor shrinkage. The mean follow-up was 4 ± 2.5 years. One radiological sign was present on initial MRI in 58% of patients and appeared during the follow-up period in the remaining 42%. Two groups were identified: 31 patients (47%) demonstrated progressive tumor regression during follow-up, and tumors in 35 patients (53%) remained stable once signs of regression were identified (assuming a stabilized regression). The prognostic factors for VS regression were as follows: EC VS extension (p = 0.02), cystic lesion (p = 0.002), and central necrosis (p = 0.02). The mean pure-tone average (PTA) was 43 ± 26.2 dB at the time of diagnosis and 53 ± 28.3 dB at the last visit (p < 0.0001). Among patients with an observed tumor shrinkage, ∆PTA was lower if the inner ear signal on the high-resolution T2-weighted image had improved (-3 ± 8.9 dB, n = 11) than if the inner ear signal had not improved (-10 ± 6.9 dB, n = 20) (p = 0.02) between the initial and last MRI scans. CONCLUSIONS: Spontaneous shrinkage of sporadic VSs could be suspected based on two radiological aspects that are indicative of VSs in progressive or stabilized regression and is an additional argument for the conservative management of these tumors. During follow-up, recovery from a reduced to a normal cochlear fluid MRI signal is a good indicator for hearing preservation.

Auditory outcomes after scala vestibuli array insertion are similar to those after scala tympani insertion 1 year after cochlear implantation.

PURPOSE: In cochlear implantation, a scala vestibuli (SV) insertion of an electrode array is a rare occurrence and is reported to be linked to poor hearing outcomes. Using the same electrode array, the auditory performance of patients with a complete SV location was compared with that of patients having a complete scala tympani (ST) location 1 year after implantation. METHODS: Thirty-three patients were included in this retrospective case-control study (SV, n = 12; ST, n = 21). The matching criteria were electrode array type, age at implantation, and duration of severe or profound deafness. The array location was analyzed using 3D reconstruction of postoperative CT scans. Postoperative audiological evaluation of the implanted ear was performed using pure-tone audiometry, speech recognition of monosyllabic words in quiet, and words and sentences in noise. RESULTS: On the preoperative CT scan, six patients in the SV group presented with both round window (RW) and ST ossification, three with RW ossification alone, and three with no RW ossification. Auditory performance did not differ between SV and ST groups 1 year after cochlear implantation. Speech recognition of words was 49 ± 7.6% and 56 ± 5.0% in quiet and 75 ± 9.5% and 66 ± 6.0% in noise in SV and ST groups, respectively. CONCLUSION: ST insertion is the gold standard that allows the three cochlear scalae to preserve scalar cochlear integrity. However, 1 year after implantation, a planned or unexpected SV insertion is not detrimental to hearing outcomes, providing similar auditory performance in quiet and noise to ST insertion.

Monitoring Cochlear Nerve Action Potential for Hearing Preservation in Medium/Large Vestibular Schwannoma Surgery: Tips and Pitfalls.

The diagnosis of large vestibular schwannomas (VS) with retained useful hearing has become increasingly common. Preservation of facial nerve (FN) function has improved using intraoperative EMG monitoring, hearing preservation remains challenging, with the recent use of cochlear nerve action potential (CNAP) monitoring. This prospective longitudinal series of VS with useful hearing operated on using a retrosigmoid approach included 37 patients with a mean largest extrameatal VS. diameter of 25 ± 8.7 mm (81% of Koos stage 4). CNAP was detected in 51% of patients, while auditory brainstem responses (ABR) were present in 22%. Patients were divided into two groups based on the initial intraoperative CNAP status, whether it was present or absent. FN function was preserved (grade I-II) in 95% of cases at 6 months. Serviceable hearing (class A + B) was preserved in 16% of the cases, while 27% retained hearing with intelligibility (class A-C). Hearing with intelligibility (class A-C) was preserved in 42% of cases when CNAP could be monitored in the early stages of VS resection versus 11% when it was initially absent. Changes in both the approach to the cochlear nerve and VS resection are mandatory in preserving CNAP and improve the rate of hearing preservation.

Simultaneous Bilateral Cochlear Implantation in Very Young Children Improves Adaptability and Social Skills: A Prospective Cohort Study.

OBJECTIVES: To investigate the value of using the Gesell Development Diagnosis Scale (GDDS) to predict developmental outcomes in very young children who undergo simultaneous bilateral cochlear implantation. DESIGN: In this prospective cohort study, a repeated-measures investigation was conducted in a tertiary referral hospital. A total of 62 children receiving simultaneous bilateral cochlear implantations were enrolled from April 2017 to August 2018. They were divided into 2 groups depending on the operative age: "Infants" group (6 to 12 months, N = 38) or "Children" group (12 to 36 months, N = 24). Data on the surgical outcomes, auditory development, speech production, and developmental indicators were collected until 2 years after the initial fitting. The primary outcome measure was the GDDS, a neuropsychological development examination. Secondary outcomes included the following: complication rate, aided pure-tone average, Infant-Toddler Meaningful Auditory Integration Scale, Categories of Auditory Performance-II, Meaningful Use of Speech Scale, Speech Intelligibility Rating, and the LittlEARS Auditory Questionnaire. RESULTS: The mean ages at implantation in infants and children groups were 9.2 ± 1.17 and 16.6 ± 3.60 months, respectively. Significant differences were found in the social skills ( p = 0.001) and adaptability ( p = 0.031) domains of GDDS. The younger the age of bilateral cochlear implants surgery, the higher developmental quotient of language, social skills, and adaptability the child could achieve after 2 years. The complication rates in the infants and children groups were 0% versus 2.1% ( p = 0.57). There was no surgical complication in the infants group. In the children group, 1 case with enlarged vestibular aqueduct and Mondini malformation had a receiver-implant misplacement on the right side (2%, 1/48). In the two groups, auditory performance and speech production had improved similarly. In the infants group, social skills developmental quotient at baseline had a significant positive relationship with Meaningful Use of Speech Scale after 2 years. CONCLUSIONS: Simultaneous bilateral cochlear implantation in younger children improves adaptability and social skills. GDDS is a sensitive tool of evaluating short-term effect of bilateral cochlear implants in neuropsychological development and constitutes a reliable predictor of speech production for the very younger pediatric cochlear implant users.

Antibiotics in mastoid and epitympanic obliteration with S53P4 bioactive glass: A retrospective study.

Objective: The role of antibiotics in ear surgery is still controversial. The aim of this study was to assess their need in cholesteatoma surgery when performing obliteration with S53P4 bioactive glass, a biocompatible material with antibacterial properties. Methods: This retrospective cohort study was conducted in a tertiary referral center between January 2017 and May 2019. Sixty-nine consecutive patients, who underwent surgery for cholesteatoma removal and/or rehabilitation of canal-wall-down mastoidectomy with mastoid and epitympanic obliteration using S53P4 granules were included. Before 2019, antibiotics were routinely used (group "w/AB"). Patients received intravenous antibiotics during surgery, oral treatment was continued for 7 days and topical antibiotics for 1 month. After 2019, no antibiotics were administered (group "w/oAB"). The primary outcome was the occurrence of early surgical site infection. Secondary outcomes were late infection, anatomic and functional results at 3 and 12 months. Results: Twenty-three patients were included in group "w/oAB" and 46 in group "w/AB", with no significant differences in demographics, medical history or follow-up. Five ears (22%) in group "w/oAB" developed an early infection compared with 2 (4%) in group "w/AB" (p = .03). The relative risk was 6.11, 95CI%[1.09;31.96]. Infections were successfully treated with antibiotics, and no patient underwent surgical removal of the granules. No late infections or complications were observed. There was no difference in graft failure or air-bone gap closure at 1 year. Conclusion: Peri-/post-operative antibiotics prevent early infection in obliteration surgery with S53P4 granules. Infections can be treated medically without complications or require removal of the implanted material. Level of evidence: 4.

Robotics, automation, active electrode arrays, and new devices for cochlear implantation: A contemporary review.

In the last two decades, cochlear implant surgery has evolved into a minimally invasive, hearing preservation surgical technique. The devices used during surgery have benefited from technological advances that have allowed modification and possible improvement of the surgical technique. Robotics has recently gained popularity in otology as an effective tool to overcome the surgeon's limitations such as tremor, drift and accurate force control feedback in laboratory testing. Cochlear implantation benefits from robotic assistance in several steps during the surgical procedure: (i) during the approach to the middle ear by automated mastoidectomy and posterior tympanotomy or through a tunnel from the postauricular skin to the middle ear (i.e. direct cochlear access); (ii) a minimally invasive cochleostomy by a robot-assisted drilling tool; (iii) alignment of the correct insertion axis on the basal cochlear turn; (iv) insertion of the electrode array with a motorized insertion tool. In recent years, the development of bone-attached parallel robots and image-guided surgical robotic systems has allowed the first successful cochlear implantation procedures in patients via a single hole drilled tunnel. Several other robotic systems, new materials, sensing technologies applied to the electrodes, and smart devices have been developed, tested in experimental models and finally some have been used in patients with the aim of reducing trauma in cochleostomy, and permitting slow and more accurate insertion of the electrodes. Despite the promising results in laboratory tests in terms of minimal invasiveness, reduced trauma and better hearing preservation, so far, no clinical benefits on residual hearing preservation or better speech performance have been demonstrated. Before these devices can become the standard approach for cochlear implantation, several points still need to be addressed, primarily cost and duration of the procedure. One can hope that improvement in the cost/benefit ratio will expand the technology to every cochlear implantation procedure. Laboratory research and clinical studies on patients should continue with the aim of making intracochlear implant insertion an atraumatic and reversible gesture for total preservation of the inner ear structure and physiology.

Hearing recovery after surgical resection of non-vestibular schwannoma cerebellopontine angle tumors.

PURPOSE: Post-operative outcomes for hearing after resection surgery to remove cerebellopontine angle (CPA) tumors other than vestibular schwannomas (VS) are not well understood. This study presents a series of patients with significant post-operative hearing recovery, trying to define the incidence among all patients operated on for removal of non-VS CPA tumors. METHODS: This is a retrospective observational case series of 8 patients among 69 operated on for removal of non-VS CPA tumors between 2012 and 2020. All patients had pre- and post-operative hearing measurement with pure-tone average (PTA) and speech discrimination score (SDS), according to the American Academy of Otolaryngology-Head and Neck Surgery recommendations, auditory brainstem response (ABR) measurements and imaging. RESULTS: Six meningiomas and two lower cranial nerve schwannomas operated on with a retrosigmoid approach were included for analysis. The mean pre-operative PTA and SDS were 58 ± 20.7 dB and 13 ± 17.5%, respectively. All patients had pre-operative class D hearing and asynchronous ABRs. They all showed significant hearing recovery, with an improvement of 36 ± 22.2 dB (p = 0.0025) and 85 ± 16.9% (p = 0.0001) in PTA and SDS, respectively, with mean follow-up of 21 ± 23.5 months. Seven patients recovered to a class A hearing level and one patient to class B. The ABRs became synchronous for three patients. The incidence of auditory recovery was 13% for patients operated on with a conservative approach (n = 60). CONCLUSION: A significant post-operative improvement in hearing could be a reasonable expectation in non-VS tumors extending into the CPA and a retrosigmoid approach should always be considered regardless of pre-operative hearing status.

Robot-Assisted Middle Ear Endoscopic Surgery: Preliminary Results on 37 Patients.

Background: Endoscopy during middle ear surgery is advantageous for better exploration of middle ear structures. However, using an endoscope has some weaknesses as surgical gestures are performed with one hand. This may trouble surgeons accustomed to using two-handed surgery, and may affect accuracy. A robot-based holder may combine the benefits from endoscopic exposure with a two-handed technique. The purpose of this study was to assess the safety and value of an endoscope held by a teleoperated system. Patients and Methods: A case series of 37 consecutive patients operated using endoscopic exposure with robot-based assistance was analyzed retrospectively. The RobOtol® system (Collin, France) was teleoperated as an endoscope holder in combination with a microscope. The following data were collected: patient characteristics, etiology, procedure type, complications, mean air and bone conduction thresholds, and speech performance at 3 months postoperatively. Patients had type I (myringoplasty), II (partial ossiculoplasty), and III (total ossiculoplasty) tympanoplasties in 15, 14, and 4 cases, respectively. Three patients had partial petrosectomies for cholesteatomas extending to the petrous apex. Finally, one case underwent resection of a tympanic paraganglioma. Ambulatory procedures were performed in 25 of the 37 patients (68%). Results: Complete healing with no perforation of the tympanic membrane was noted postoperatively in all patients. No complications relating to robotic manipulation occurred during surgery or postoperatively. The mean air conduction gain was 3.8 ± 12.6 dB for type I (n = 15), 7.9 ± 11.4 dB for type II (n = 14), and -0.9 ± 10.8 for type III tympanoplasties (n = 4), and the postoperative air-bone conduction gap was 13.8 ± 13.3 dB for type I, 19.7 ± 11.7 dB for type II and 31.6 ± 13.0 dB for type III tympanoplasty. They was no relapse of cholesteatoma or paraganglioma during the short follow-up period (<1 year). Conclusion: This study indicates that robot-assisted endoscopy is a safe and trustworthy tool for several categories of middle ear procedures. It combines the benefits of endoscopic exposure with a two-handed technique in middle ear surgery. It can be used as a standalone tool for pathology limited to the middle ear cleft or in combination with a microscope in lesions extending to the mastoid or petrous apex.

Restoration of High Frequency Auditory Perception After Robot-Assisted or Manual Cochlear Implantation in Profoundly Deaf Adults Improves Speech Recognition.

Background and Purpose: Robot-assisted cochlear implantation has recently been implemented in clinical practice; however, its effect on hearing outcomes is unknown. The aim of this preliminary study was to evaluate hearing performance 1 year post-implantation whether the electrode array was inserted manually or assisted by a robot. Methods: Forty-two profoundly deaf adults were implanted either manually (n = 21) or assisted by a robot (RobOtol®, Collin, Bagneux, France) with three different electrode array types. Participants were paired by age, and electrode array type. The scalar position of the electrode array in the cochlea was assessed by 3D reconstruction from the pre- and post-implantation computed tomography. Pure-tone audiometry and speech perception in silence (percentage of disyllabic words at 60 dB) were tested on the implanted ear 1 year post-implantation in free-field conditions. The pure-tone average was calculated at 250-500-750 Hz, 500-1,000-2,000-3,000 Hz, and 3,000-4,000-8,000 Hz for low, mid, and high frequencies, respectively. Results: One year after cochlear implantation, restoration of the high-frequency thresholds was associated with better speech perception in silence, but not with low or mid frequencies (p < 0.0001; Adjusted R 2 = 0.64, polynomial non-linear regression). Although array translocation was similar using either technique, the number of translocated electrodes was lower when the electrode arrays had been inserted with the assistance of the robot compared with manual insertion (p = 0.018; Fisher's exact test). Conclusion: The restoration of high-frequency thresholds (3,000-4,000-8,000 Hz) by cochlear implantation was associated with good speech perception in silence. The numbers of translocated electrodes were reduced after a robot-assisted insertion.

Robot-Assisted Electrode Array Insertion Becomes Available in Pediatric Cochlear Implant Recipients: First Report and an Intra-Individual Study.

Background: As an advanced surgical technique to reduce trauma to the inner ear, robot-assisted electrode array (EA) insertion has been applied in adult cochlear implantation (CI) and was approved as a safe surgical procedure that could result in better outcomes. As the mastoid and temporal bones are generally smaller in children, which would increase the difficulty for robot-assisted manipulation, the clinical application of these systems for CI in children has not been reported. Given that the pediatric candidate is the main population, we aim to investigate the safety and reliability of robot-assisted techniques in pediatric cochlear implantation. Methods: Retrospective cohort study at a referral center in Shanghai including all patients of simultaneous bilateral CI with robotic assistance on one side (RobOtol® system, Collin ORL, Bagneux, France), and manual insertion on the other (same brand of EA and CI in both side), from December 2019 to June 2020. The surgical outcomes, radiological measurements (EA positioning, EA insertion depth, mastoidectomy size), and audiological outcomes (Behavior pure-tone audiometry) were evaluated. Results: Five infants (17.8 ± 13.5 months, ranging from 10 to 42 months) and an adult (39 years old) were enrolled in this study. Both perimodiolar and lateral wall EAs were included. The robot-assisted EA insertion was successfully performed in all cases, although the surgical zone in infants was about half the size in adults, and no difference was observed in mastoidectomy size between robot-assisted and manual insertion sides (p = 0.219). The insertion depths of EA with two techniques were similar (P = 0.583). The robot-assisted technique showed no scalar deviation, but scalar deviation occurred for one manually inserted pre-curved EA (16%). Early auditory performance was similar to both techniques. Conclusion: Robot-assisted technique for EA insertion is approved to be used safely and reliably in children, which is possible and potential for better scalar positioning and might improve long-term auditory outcome. Standard mastoidectomy size was enough for robot-assisted technique. This first study marks the arrival of the era of robotic CI for all ages.

Thermal Safety of Endoscopic Usage in Robot-Assisted Middle Ear Surgery: An Experimental Study.

Objectives: The widespread application of endoscopic ear surgery (EES), performed through the external auditory canal, has revealed the limitations of the one-handed technique. The RobOtol® (Collin ORL, Bagneux, France) otological robotic system has been introduced to enable two-handed procedures; however, the thermal properties of dedicated endoscopes, which are usually used in neurosurgery, called "neuro-endoscopes," have not yet been clarified for the robotic systems. In this study, we aimed to profile the thermal characteristics of two dedicated neuro-endoscopes, as compared to endoscopes used routinely in manual EES, called "oto-endoscopes," and defined by a smaller diameter and shorter length, and to discuss the safe application of robotic assistance in EES. Methods: Two neuro-endoscopes (3.3 mm, 25 cm, 0°/30°) were studied using two routine light sources (LED/xenon), and two routine oto-endoscopes (3 mm, 14 cm, 0°/30°) were initially measured to provide a comprehensive comparison. Light intensities and temperatures were measured at different power settings. The thermal distributions were measured in an open environment and a human temporal bone model of EES. The cooling measures were also studied. Results: Light intensity was correlated with stabilized tip temperatures (P < 0.01, R 2 = 0.8719). Under 100% xenon power, the stabilized temperatures at the tips of 0°, 30° neuro-endoscopes, and 0°, 30° oto-endoscopes were 96.1, 60.1, 67.8, and 56.4°C, respectively. With 100% LED power, the temperatures decreased by about 10°C, respectively. For the 0° neuro-endoscope, the illuminated area far away 1cm from the tip was below 37°C when using more than 50% both power, while this distance for 30° neuro-endoscope was 0.5 cm. In the EES temporal bone model, the round window area could reach 59.3°C with the 0° neuro-endoscope under 100% xenon power. Suction resulted in a ~1-2°C temperature drop, while a 10 mL saline rinse gave a baseline temperature which lasted for 2.5 min. Conclusion: Neuro-endoscope causes higher thermal releasing in the surgical cavity of ESS, which should be especially cautious in the robotic system usage. Applying submaximal light intensity, a LED source and intermittent rinsing should be considered for the safer robot-assisted EES using a neuro-endoscope that allows a two-handed surgical procedure.

Intraoperative facial nerve electromyography parameters to optimize postoperative facial nerve outcome in patients with large unilateral vestibular schwannoma.

BACKGROUND: Decision-making for large sporadic vestibular schwannomas (VS) resection guided by the intraoperative change in supramaximal facial nerve (FN) amplitude and latency response to optimize post-operative FN outcome. METHODS: Prospectively study of 43 patients, from January to December 2018, of large sporadic VS with preoperative normal FN function at our center. Tumors were removed through retrosigmoid (81%) or translabyrinthine (19%) approaches with FN monitoring. Intraoperative pre- and post-VS resection supramaximal (2 mA) amplitude and latency responses at the proximal FN root were recorded. RESULTS: Total, near-/subtotal VS resections (TR, NTR, STR) were achieved in 51%, 38%, and 11% of tumors, respectively, guided by no more than 40% decrease in supramaximal amplitude. Pre- and post-resection supramaximal amplitude and latency responses were lower and longer, respectively, in NTR+STR than in TR. At day 8, FN function was grade I-II in 77% of patients and grade III-V in 23%, and after 6 months, it was in grade I-II in 95% and grade III in 5%, and there was no significant difference between TR and NTR+STR. Facial palsy occurred in older patients and in the case of severe FN adhesion. At day 8, pre- and post-resection supramaximal amplitude but not latency responses were different between FN grade III-V and grade I-II. Serviceable hearing was preserved in 28% of large VS. CONCLUSIONS: Intraoperative FN monitoring guided VS resection in large VS so that 49% retained some residual tumor. Accordingly, 95% good postoperative FN function and significant hearing preservation were achieved after 6 months.

Analysis of forces during robot-assisted and manual manipulations of mobile and fixed footplate in temporal bone specimens.

PURPOSE: To evaluate the forces involved in different manipulations, manual or robot-assisted, applied to the ossicular chain, on normal temporal bones and on an anatomical model of otosclerosis. METHODS: Thirteen cadaveric temporal bones, with mobile footplates or with footplates that were fixed using hydroxyapatite cement, were manipulated, manually or using a robotic arm (RobOtol®). "Short contact" of a mobile footplate was the weakest interaction on the incus. "Long contact" was the same manipulation held for 10 s. "Mobilization" was the smallest visualized movement of the mobile footplate, or the movement necessary to regain mobility of the fixed footplate. A six-axis force sensor (Nano17, ATI) measured the maximal peak of forces, summation of forces applied, and yank. RESULTS: Maximal forces during short (~4 mN) and long contact (~15 mN) were similar for manual and robot-assisted manipulations. For manual manipulation, yank measured during long contact was twice as high compared to robot-assisted manipulation: 6 ± 2.4 (n = 5) and 3 ± 1.3 mN/s (n = 5), respectively (mean ± SD, p < 0.02). For mobilization of the mobile footplate, maximal forces during mobilization were similar during manual and robot-assisted manipulations, respectively: 12 ± 2.5 (n = 6) and 19 ± 7.6 mN (n = 7). Compared with mobilization of a mobile footplate, mobilization of a fixed footplate required ~ 60 and ~ 27 times higher maximal forces for manual and robot-assisted manipulations, respectively: 724 ± 366.4 and 507 ± 283.2 mN. Yank was twice as high during manual manipulation compared to robot-assisted manipulation (p < 0.05). CONCLUSION: Robot-assisted manipulation of the ossicular chain was reliable. Our anatomical model of otosclerosis was successfully developed requiring higher forces for stapes mobilization.

Objective improvement in adults with cerebellopontine angle arachnoid cysts after surgical treatment.

BACKGROUND: Intracranial arachnoid cysts are extra-axial benign lesions mainly found in the middle cerebral fossa. Rare case series report various cranial nerve dysfunctions associated with cerebellopontine angle (CPA) cysts and there is no consensus with regard to their surgical management; some reports claiming that subjective improvement in adults with intracranial arachnoid cysts cannot justify surgical treatment. METHODS: This retrospective study included all 12 consecutive adult patients treated by microsurgical fenestration for symptomatic CPA arachnoid cysts between 2010 and 2019 and using a retrosigmoid approach. Demographic, clinical, surgical, and radiological data were collected from medical files. RESULTS: The main symptoms were audiovestibular in 9 patients (75%) complaining of dizziness and 6 patients (50%) with hearing loss. In addition, 3 patients (25%) reported tinnitus, 3 patients (25%) presented vasovagal syncope, and 1 patient (8.3%) reported facial pain. Surgery improved 5 patients (83%) with pre-operative hearing loss, 7 patients (78%) reporting dizziness, and all patients with vasovagal syncope. All of the patients recovered from at least one symptom. No recurrence was observed with a mean follow-up of 5.5 years. CONCLUSION: Although most arachnoid cysts are asymptomatic, the CPA location may lead to cranial nerve impairments. Microsurgical fenestration seems to be a simple, safe, and effective technique.

Metachronous Bilateral Vestibular Schwannomas.

Bilateral vestibular schwannoma (BVS) is the hallmark of neurofibromatosis type 2 (NF2), both of them being present at diagnosis. We report four cases of metachronous BVS, a contralateral intracanalicular vestibular schwannomas (VS) being visible 2 to 13 years after resection of a unilateral VS. NF2 workup was negative except in one case where two NF2 gene mutations were found in tumor analysis. These cases raise the questions of whether the contralateral VS occurred by chance and how to manage it on the only hearing ear. Otologists should be aware of this rare eventuality for decision making of the first unilateral VS. Laryngoscope, 131:E250-E254, 2021.

Management and Outcomes of Sporadic Vestibular Schwannoma: A Longitudinal Study Over 12 Years.

OBJECTIVES: To evaluate the management of sporadic vestibular schwannomas (VS) with a 12-year follow-up. STUDY DESIGN: Retrospective study of all VS patients initially treated in 2005 in a tertiary referent center. METHODS: Initial decision making for microsurgical resection (MSR) or wait-and-scan (WaS) was according to VS size and hearing; subsequently, MSR or stereotactic radiosurgery (SRS) was proposed dependent on VS growth and size, hearing, and patient's age or willingness. RESULTS: Two hundred and one sporadic VS were included. The first management apportionment was 120 WaS (61.5%), 72 MSR (37%), three SRS (1.5%), and six others refused MSR and were lost to follow-up (LFU). Within 1 year, 95 (47%) VS were surgically removed; 17 (8.5%) were treated by SRS; and 35 (17.5%) were LFU. The proportions for SRS and LFU were virtually unchanged for the following years, and the proportion under MSR increased slightly within 3 years and then remained stable. Finally, at 12 years, 104 (51.5%) cases had been operated on, 21 (10.5%) treated by SRS, 23 (11.5%) still under WaS, and 53 (26.5%) LFU, which were mainly intracanalicular. The initially and subsequently operated cases presented similar hearing preservation rates and good facial nerve function outcomes. CONCLUSION: This longitudinal study of a large number of VS, which were diagnosed over a short period of time and followed for 12 years, provides new information on both the natural history of these benign tumors and individual patient concerns. This study recommends use of the WaS policy for small and mid-sized VS before active therapeutic decision making. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:E970-E976, 2021.