Preclinical evaluation of a tool for insertion force measurements in cochlear implant surgery.

PURPOSE: Trauma that may be inflicted to the inner ear (cochlea) during the insertion of an electrode array (EA) in cochlear implant (CI) surgery can significantly decrease the hearing outcome of patients with residual hearing. Interaction forces between the EA and the cochlea are a promising indicator for the likelihood of intracochlear trauma. However, insertion forces have only been measured in laboratory setups. We recently developed a tool to measure the insertion force during CI surgery. Here, we present the first ex vivo evaluation of our tool with a focus on usability in the standard surgical workflow. METHODS: Two CI surgeons inserted commercially available EAs into three temporal bone specimens. The insertion force and the orientation of the tool were recorded together with camera footage. The surgeons answered a questionnaire after each insertion to evaluate the surgical workflow with respect to CI surgery. RESULTS: The EA insertion using our tool was rated successful in all 18 trials. The surgical workflow was evaluated to be equivalent to standard CI surgery. Minor handling challenges can be overcome through surgeon training. The peak insertion forces were 62.4 mN ± 26.7 mN on average. Peak forces significantly correlated to the final electrode insertion depth, supporting the assumption that the measured forces mainly correspond to intracochlear events and not extracochlear friction. Gravity-induced forces of up to 28.8 mN were removed from the signal, illustrating the importance of the compensation of such forces in manual surgery. CONCLUSION: The results show that the tool is ready for intraoperative use. In vivo insertion force data will improve the interpretability of experimental results in laboratory settings. The implementation of live insertion force feedback to surgeons could further improve residual hearing preservation.

Drilling accuracy evaluation of a mouldable surgical targeting system for minimally invasive access to anatomic targets in the temporal bone.

PURPOSE: Minimally invasive cochlear implant surgery using a micro-stereotactic surgical targeting system with on-site moulding of the template aims for a reliable, less experience-dependent access to the inner ear under maximal reduction of trauma to anatomic structures. We present an accuracy evaluation of our system in ex-vivo testing. METHODS: Eleven drilling experiments were performed on four cadaveric temporal bone specimens. The process involved preoperative imaging after affixing the reference frame to the skull, planning of a safe trajectory preserving relevant anatomical structures, customization of the surgical template, execution of the guided drilling and postoperative imaging for determination of the drilling accuracy. Deviation between the drilled and desired trajectories was measured at different depths. RESULTS: All drilling experiments were successfully performed. Other than purposely sacrificing the chorda tympani in one experiment, no other relevant anatomy, such as facial nerve, chorda tympani, ossicles or external auditory canal were harmed. Deviation between the desired and achieved path was found to be 0.25 ± 0.16 mm at skulls' surface and 0.51 ± 0.35 mm at the target level. The closest distance of the drilled trajectories' outer circumference to the facial nerve was 0.44 mm. CONCLUSIONS: We demonstrated the usability for drilling to the middle ear on human cadaveric specimen in a pre-clinical setting. Accuracy proved to be suitable for many applications such as procedures within the field of image-guided neurosurgery. Promising approaches to reach sufficient submillimetre accuracy for CI surgery have been outlined.

A Tool to Enable Intraoperative Insertion Force Measurements for Cochlear Implant Surgery.

OBJECTIVE: Residual hearing preservation during cochlear implant (CI) surgery is closely linked to the magnitude of intracochlear forces acting during the insertion process. So far, these forces have only been measured in vitro. Therefore, the range of insertion forces and the magnitude of damage-inducing thresholds in the human cochlea in vivo remain unknown. We aimed to develop a method to intraoperatively measure insertion forces without negatively affecting the established surgical workflow. Initial experiments showed that this requires the compensation of orientation-dependent gravitational forces. METHODS: We devised design requirements for a force-sensing manual insertion tool. Experienced CI surgeons evaluated the proposed design for surgical safety and handling quality. Measured forces from automated and manual insertions into an artificial cochlea model were evaluated against data from a static external force sensor representing the gold standard. RESULTS: The finalized manual insertion tool uses an embedded force sensor and inertial measurement unit to measure insertion forces. The evaluation of the proposed design shows the feasibility of orientation-independent insertion force measurements. Recorded forces correspond well to externally recorded reference forces after reliable removal of gravitational disturbances. CI surgeons successfully used the tool to insert electrode arrays into human cadaver cochleae. CONCLUSION: The presented positive evaluation poses the first step towards intraoperative use of the proposed tool. Further in vitro experiments with human specimens will ensure reliable in vivo measurements. SIGNIFICANCE: Intraoperative insertion force measurements enabled by this tool will provide insights on the relationship between forces and hearing outcomes in cochlear implant surgery.

Ex Vivo Evaluation of a Minimally Invasive Approach for Cochlear Implant Surgery.

OBJECTIVES: Drilling a minimally invasive access to the inner ear is a demanding task in which a computer-assisted surgical system can support the surgeon. Herein, we describe the design of a new micro-stereotactic targeting system dedicated to cochlear implant (CI) surgery and its experimental evaluation in an ex vivo study. METHODS: The proposed system consists of a reusable, bone-anchored reference frame, and a patient-specific drilling jig on top of it. Individualization of the jig is simplified to a single counterbored hole drilled out of a blank. For accurate counterboring, the setup includes a manufacturing device for individual positioning of the blank. The system was tested in a preclinical setting using twelve human cadaver donors. Cone beam computed tomograph (CBCT) scans were obtained and a drilling trajectory was planned pointing towards the basal part of the cochlea. The surgical drill was moved forward manually and slowly while the jig constrained the drill along the predetermined path. RESULTS: Drilling could be performed with preservation of facial nerve in all specimens. The mean error caused by the system at the target point in front of the cochlea was 0.30 mm ± 0.11 mm including an inaccuracy of 0.09 mm ± 0.03 mm for counterboring the guiding aperture into the jig. CONCLUSION: Feasibility of the proposed system to perform a minimally invasive posterior tympanotomy approach was shown successfully in all specimens. SIGNIFICANCE: First evaluation of the new system in a comprehensive ex vivo study demonstrating sufficient accuracy and the feasibility of the whole concept.

Toward a cochlear implant electrode array with shape memory effect for post-insertion perimodiolar positioning.

For cochlear implants (CI) a final position of the electrode array (EA) along the inner wall of the spirally shaped cochlea is considered to be beneficial because it results in a closer proximity to the auditory nerve fibers. A shape memory effect (SME) could facilitate such shift of the EA toward the cochlear inner wall, but its implementation remains to be solved. The current study presents an EA prototype featuring the SME with minute adjustments of the material properties of Nitinol, a shape memory alloy, in combination with a suitable cooling strategy to prevent premature curling. Ten samples were successfully inserted by a CI surgeon into an artificial cochlear model submerged into a temperature-controllable water bath to simulate temporary hypothermia of the inner ear (31°C). Gentle insertions were possible, with an average insertion speed of 0.81 ± 0.14 mm/s. After recovery of body temperature, the desired position shift toward the modiolus was observed in all trials. Angular insertion depth increased by approximately 81.8° ± 23.4°. We demonstrate for the first time that using the body temperature responsive SME for perimodiolar EA positioning is feasible and does not impede a gentle surgical insertion.

The Effect of Ultra-slow Velocities on Insertion Forces: A Study Using a Highly Flexible Straight Electrode Array.

OBJECTIVE: The present study sought to 1) characterize insertion forces resulting from a flexible straight electrode array (EA) inserted at slow and ultra-slow insertion velocities, and 2) evaluate if ultra-slow velocities decrease insertion forces independent of other variables. BACKGROUND: Low insertion forces are desirable in cochlear implant (CI) surgery to reduce trauma and preserve hearing. Recently, ultra-slow insertion velocities (lower than manually feasible) have been shown to produce significantly lower insertion forces using other EAs. METHODS: Five flexible straight EAs were used to record insertion forces into an inelastic artificial scala tympani model. Eleven trial recordings were performed for each EA at five predetermined automated, continuous insertion velocities ranging from 0.03 to 1.6 mm/s. RESULTS: An ultra-slow insertion velocity of 0.03 mm/s resulted in a median insertion force of 0.010 N at 20 mm of insertion depth, and 0.026 N at 24.3 mm-the final insertion depth. These forces represent only 24 to 29% of those measured using 1.6 mm/s. After controlling for insertion depth of the EA into the artificial scala tympani model and trial insertion number, decreasing the insertion velocity from 0.4 to 0.03 mm/s resulted in a 50% decrease in the insertion forces. CONCLUSION: Using the tested EA ultra-slow velocities can decrease insertion forces, independent of variables like insertion depth. Our results suggest ultra-slow velocities can reduce insertion forces at least 60%, compared with humanly feasible continuous velocities (≥0.9 mm/s).

Reducing Sound Exposure During Ocular Vestibular Evoked Myogenic Potential Testing for Superior Semicircular Canal Dehiscence Syndrome.

BACKGROUND: Ocular vestibular evoked myogenic potentials (oVEMP) testing in response to air-conducted sound (ACS) has excellent sensitivity and specificity for superior semicircular canal dehiscence syndrome (SCDS). However, patients with SCDS may experience vertigo with the test, and recent works recommend minimizing acoustic energy during VEMP testing. PURPOSE: To develop an oVEMP protocol that reduces discomfort and increases safety without compromising reliability. METHODS: Subjects: Fifteen patients diagnosed with SCDS based on clinical presentation, audiometry, standard VEMP testing, and computed tomography (CT) imaging. There were 17 SCDS-affected ears and 13 unaffected ears. In nine (53%) of the SCDS-affected ears surgical repair was indicated, and SCD was confirmed in each. oVEMPs were recorded in response to ACS using 500 Hz tone bursts or clicks. oVEMP amplitudes evoked by 100 stimuli (standard protocol) were compared with experimental protocols with only 40 or 20 stimuli. RESULTS: In all three protocols, oVEMP amplitudes in SCDS-affected ears were significantly higher than in the unaffected ears (p < 0.001). 500 Hz tone bursts evoked oVEMPs with excellent (>90%) sensitivity and specificity in each of the three protocols. However, in the unaffected ears, lowering to 20 stimuli reduced the detection of oVEMP responses in some ears. Following surgical repair, oVEMPs normalized in each of the protocols. CONCLUSION: In oVEMP testing using ACS for SCDS, reducing the number of trials from 100 to 40 stimuli results in a more tolerable and theoretically safer test without compromising its effectiveness for the diagnosis of SCDS. Reducing to 20 stimuli may degrade specificity with clicks.

Teacher Prescreening for Hearing Loss in the Developing World.

The goal of this prospective cohort study was to characterize the ability of teachers to identify schoolchildren at risk of hearing loss in order to maximize hearing screening efficiency in low-resource settings. At 4 semirural schools in Malindi, Kenya, preselected schoolchildren perceived as hearing impaired were compared to children thought to have normal hearing using portable audiometry. Eight of 127 children (54% male) failed hearing screening, all of who were identified by schoolteachers as having a high risk of hearing loss. Thus, for every 5 children prescreened by schoolteachers, an average of 1 child would be identified as having hearing loss. Overall, teacher prescreening had a 100% hearing loss identification rate and a 20% referral rate. In conclusion, in resource-limited settings, where universal hearing screening is challenging, teachers can effectively identify children with hearing loss for early intervention.

A simple tool to automate the insertion process in cochlear implant surgery.

PURPOSE: Automated insertion of electrode arrays (EA) in cochlear implant surgery is presumed to be less traumatic than manual insertions, but no tool is widely available in the operating room. We sought (1) to design and create a simple tool able to automate the EA insertion process; and (2) to perform preliminary evaluations of the designed prototype. METHODS: A first prototype of a tool with maximum simplicity was designed and fabricated to take advantage of hydraulic actuation. The prototype facilitates automated forward motion using a syringe connected to an infusion pump. Initial prototype evaluation included: (1) testing of forward motion at different velocities (2) EA insertion trials into an artificial cochlear model with force recordings, and (3) evaluation of device handling, fixation and positioning using cadaver head specimens and a surgical retractor. Alignment of the tool was explored with CT imaging. RESULTS: In this initial phase, the prototype demonstrated easy assembly and ability to respond to hydraulic actuation driven by an infusion pump at different velocities. EA insertions at an ultra-slow velocity of 0.03 mm/s revealed smooth force profiles with mean maximum force of 0.060 N ± 0.007 N. Device positioning with an appropriate insertion axis into the cochlea was deemed feasible and easy to achieve. CONCLUSIONS: Initial testing of our hydraulic insertion tool did not reveal any serious complications that contradict the initially defined design specifications. Further meticulous testing is needed to determine the safety of the device, its reliability and clinical applicability.

Correlation of air-bone gap and size of Enlarged Vestibular Aqueduct in children.

OBJECTIVE: Enlarged vestibular aqueduct (EVA) is an inner ear malformation that represents an important cause of pediatric hearing loss. While certain elements in the history or audiogram may suggest EVA, it is most often diagnosed using computed tomography (CT). The present investigation was conducted to determine if the size of the audiometric air-bone gap (ABG) is correlated with the size of the vestibular aqueduct in the pediatric population using three vestibular aqueduct measurements. These included the fundus, midpoint, and porous widths of the vestibular aqueduct. STUDY DESIGN: This is a retrospective cohort study. SETTING: This study took place at a tertiary care referral center. PATIENTS: Fifty-five children (33 female; 22 male) with a confirmed diagnosis of unilateral or bilateral EVA as determined by prior imaging of the inner ear were included in the study. MAIN OUTCOME MEASURES: Associations of EVA measurements with ABGs at 0.5 and 1 kHz were evaluated using Pearson correlation coefficients. RESULTS: All of the correlation coefficients were positive, indicating that as EVA measurements increased so did the ABG. Only the correlation between fundus width and ABG at 1 kHz was not statistically significant. CONCLUSIONS: ABGs measured during audiometric testing correlate with the size of the EVA and ABGs can be clinical predictors of the severity of the bony abnormality. These data support the third window theory of conductive hearing loss in pediatric EVA.

Characterizing the size of the target region for atraumatic opening of the cochlea through the facial recess.

Surgical treatment with a cochlear implant (CI) for hearing rehabilitation requires a highly accurate and personalized opening of the inner ear (cochlea) to protect the delicate intra-cochlear fine structures, whose functional integrity needs to be maintained to preserve residual hearing. Spatial orientation within the complex anatomy of the lateral skull base during the procedure is a highly demanding task for the surgeon. In order to reduce risk of facial nerve palsy and loss of residual hearing as well as to establish minimally invasive CI surgery (minCIS), image-guided procedures incorporating surgical assistance systems are under development. However, there is a lack of an accuracy threshold value or range that such a system needs to fulfill to be considered sufficiently accurate for atraumatic opening of the inner ear. In this study, high resolution three-dimensional (3D) morphological images of eight human temporal bone specimens were manually segmented to build anatomical models of the human inner ear including all surgically relevant intra-cochlear structures as well as the facial recess. These 3D models were used to plan the surgical access path to the basal turn of the cochlea using the mastoidectomy posterior tympanotomy approach (MPTA). Therefore, custom-made image-processing software was developed to perform both path planning and identification of the valid target region- i.e., the largest possible region for atraumatic opening of the scala tympani. The developed 3D models provide visualization of the complex and variable anatomy of the basal portion of the human cochlear duct (also known as cochlear "hook region") as well as its spatial relationship to the facial recess. Their spatial arrangement directly impacts the accessibility of the hook region and limits the entry direction into scala tympani. The average diameter of the target region was found to be 1.56 mm ±â€¯0.10 mm (range: 1.43 to 1.72 mm). The anatomic variability and the need for a high safety level of at least 95% for hearing preservation CI surgery lead to a remaining safety margin of approximately 0.3 mm. In the future, this accuracy threshold value can serve as benchmark during the pre-clinical evaluation of image-guidance technologies to allow for highly accurate CI surgery.

Community health workers obtain similar results using cell-phone based hearing screening tools compared to otolaryngologists in low resourced settings.

OBJECTIVE: To establish community health workers as reliable hearing screening operators in a technology-based pre-surgical hearing screening program in a low and middle-income country (LMIC). METHODS: This is a cross sectional study that evaluated community health worker driven hearing screening that took place in semi-rural Malindi, Kenya during an annual two-week otolaryngology surgical training mission in October 2017. At five separate locations (four schools) near Malindi, Kenya, children between the ages of 2-16 underwent hearing screening using screening audiometry (Android-based HearX Group). Children were screened by a community health worker who underwent a short training course, a senior otolaryngology resident, or both. Hearing screening results were compared to determine the reliability and concordance between independent, blinded community health worker and otolaryngology resident testing. RESULTS: One hundred and four participants (53% males) underwent hearing screening. Hearing screening pass rate was 93%. Community health workers obtained a similar result to otolaryngology residents 96% of the time (McNemar test: p = 0.16, OR 0.96, 95% CI 0.9-1.0). CONCLUSION: Community health workers can obtain reliable results using a technology-based, pre-surgical hearing screening platform when compared to otolaryngology residents. This finding has profound implications in low-resourced settings where hearing healthcare specialists (audiologists and otolaryngologists) are limited and can ultimately improve the surgical yield of patients presenting to local otolaryngologists in these settings.

Pre-operative Screening and Manual Drilling Strategies to Reduce the Risk of Thermal Injury During Minimally Invasive Cochlear Implantation Surgery.

This article presents the development and experimental validation of a methodology to reduce the risk of thermal injury to the facial nerve during minimally invasive cochlear implantation surgery. The first step in this methodology is a pre-operative screening process, in which medical imaging is used to identify those patients that present a significant risk of developing high temperatures at the facial nerve during the drilling phase of the procedure. Such a risk is calculated based on the density of the bone along the drilling path and the thermal conductance between the drilling path and the nerve, and provides a criterion to exclude high-risk patients from receiving the minimally invasive procedure. The second component of the methodology is a drilling strategy for manually-guided drilling near the facial nerve. The strategy utilizes interval drilling and mechanical constraints to enable better control over the procedure and the resulting generation of heat. The approach is tested in fresh cadaver temporal bones using a thermal camera to monitor temperature near the facial nerve. Results indicate that pre-operative screening may successfully exclude high-risk patients and that the proposed drilling strategy enables safe drilling for low-to-moderate risk patients.

Automatic Cochlear Duct Length Estimation for Selection of Cochlear Implant Electrode Arrays.

HYPOTHESIS: Cochlear duct length (CDL) can be automatically measured for custom selection of cochlear implant (CI) electrode arrays. BACKGROUND: CI electrode array selection can be influenced by measuring the CDL, which is estimated based on the length of the line that connects the round window and the lateral wall of the cochlea when passing through the modiolus. CDL measurement remains time consuming and inter-observer variability has not been studied. METHODS: We evaluate an automatic approach to directly measure the two-turn (2T) CDL using existing algorithms for localizing cochlear anatomy in computed tomography (CT). Pre-op CT images of 309 ears were evaluated. Two fellowship-trained neurotologists manually and independently measured CDL. Inter-observer variability between measurements across expert and automatic observers is assessed. Inter-observer differences for choice of electrode type are also investigated. RESULTS: Manual measurement of CDL by experts tends to underestimate cochlea size and has high inter-observer variability, with mean absolute differences between expert CDL estimations of 1.15 mm. Our results show that this can lead to a large number of cochleae for which a different electrode array type would be selected by different observers, depending on the specific threshold value of CDL used to decide between array type. CONCLUSION: Choosing the best CI electrode array is an important task for optimizing hearing outcomes. Manual cochleae length measurements are user-dependent, and errors impact upon the CI electrode array choice for certain patients. Measuring cochlea length automatically is less time consuming and generates more repeatable results. Our automatic approach could make use of CDL for patient-customized treatment more clinically adoptable.

Tip Fold-over in Cochlear Implantation: Case Series.

OBJECTIVE: To describe the incidence, clinical presentation, and performance of cochlear implant (CI) recipients with tip fold-over. STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. PATIENTS: CI recipients who underwent postoperative computed tomography (CT) scanning. INTERVENTION(S): Tip fold-over was identified tomographically using previously validated software that identifies the electrode array. Electrophysiologic testing including spread of excitation or electric field imaging (EFI) was measured on those with fold-over. MAIN OUTCOME MEASURE(S): Location of the fold-over; audiological performance pre and postselective deactivation of fold-over electrodes. RESULTS: Three hundred three ears of 235 CI recipients had postoperative CTs available for review. Six (1.98%) had tip fold-over with 5/6 right-sided ears. Tip fold-over occurred predominantly at 270 degrees and was associated with precurved electrodes (5/6). Patients did not report audiological complaints during initial activation. In one patient, the electrode array remained within the scala tympani with preserved residual hearing despite the fold-over. Spread of excitation supported tip fold-over, but the predictive value was not clear. EFI predicted location of the fold-over with clear predictive value in one patient. At an average follow-up of 11 months, three subjects underwent deactivation of the overlapping electrodes with two of them showing marked audiological improvement. CONCLUSION: In a large academic center with experienced surgeons, tip fold-over occurred at a rate of 1.98% but was not immediately identifiable clinically. CT imaging definitively showed tip fold-over. Deactivating involved electrodes may improve performance possibly avoiding revision surgery. EFI may be highly predictive of tip fold-over and can be run intraoperatively, potentially obviating the need for intraop fluoroscopy.

Evaluation of Rigid Cochlear Models for Measuring Cochlear Implant Electrode Position.

OBJECTIVE: To investigate the accuracy of rigid cochlear models in measuring intra-cochlear positions of cochlear implant (CI) electrodes. PATIENTS: Ninety three adults who had undergone CI and pre- and postoperative computed tomographic (CT) imaging. MAIN OUTCOME MEASURES: Seven rigid models of cochlear anatomy were constructed using micro-CTs of cochlear specimens. Using each of the seven models, the position of each electrode in each of the 98 ears in our dataset was measured as its depth along the length of the cochlea, its distance to the basilar membrane, and its distance to the modiolus. Cochlear duct length was also measured using each model. RESULTS: Standard deviation (SD) across rigid cochlear models in measures of electrode depth, distance to basilar membrane, distance to modiolus, and length of the cochlear duct at two turns were 0.68, 0.11, 0.15, and 1.54 mm. Comparing the estimated position of the electrodes with respect to the basilar membrane, i.e., deciding whether an electrode was located within the scala tympani (ST) or the scala vestibuli (SV), there was not a unanimous agreement between the models for 19% of all the electrodes. With respect to the modiolus, each electrode was classified into one of the three groups depending on its modiolar distance: close, medium, and far. Rigid models did not unanimously agree on modiolar distance for approximately 50% of the electrodes tested. CONCLUSIONS: Inter-model variance of rigid cochlear models exists, demonstrating that measurements made using rigid cochlear models are limited in terms of accuracy because of non-rigid inter-subject variations in cochlear anatomy.

Pediatric Endoscopic Cholesteatoma Surgery.

OBJECTIVES: (1) To describe and review a single center's pediatric endoscopic cholesteatoma experience, including surgical and audiologic outcomes. (2) To assess the most common locations of residual cholesteatoma following endoscopic removal. STUDY DESIGN: Case series with chart review. SETTING: Tertiary otologic referral center. SUBJECTS: Patients <19 years of age who underwent cholesteatoma removal with either endoscopic or microscopic visualization. METHODS: In a comparison of patients who underwent total endoscopic ear surgery (TEES), combined endoscopic-microscopic surgery, or microscopic surgery, analyzed outcomes included locations and incidence of recurrent and residual cholesteatoma, complications, and audiometric testing. RESULTS: Sixty-six patients (mean age, 10.9 years; range, 4-18 years; 43.4% female) with 76 ears met inclusion criteria. The average overall follow-up was 18.8 months (range, 6.7-48.3). Forty-seven (61.8%) ears underwent microscopic removal of cholesteatoma; 29 (38.1%) ears underwent combined endoscopic-microscopic removal; and 8 (10.5%) ears underwent TEES removal. Significantly more mastoidectomies were completed in microscopic cases as compared with endoscopic cases (P = .049). Though second-look procedures occurred in 15 (51.7%) endoscopic cases and 10 (21.3%) microscopic cases (P = .006), the rate of residual disease was 20.0% and 40.0% in endoscopic and microscopic cases, respectively (P = .38). When controlling for preoperative hearing, only the air-bone gap for TEES demonstrated significant improvement (P = .009). No complications were noted. CONCLUSION: The present report describes our experience with pediatric endoscopic cholesteatoma surgery, demonstrating similar hearing outcomes, rates of recurrence and residual disease, and complication rates as compared with traditional microscopic techniques.

Surgical and Audiologic Outcomes in Endoscopic Stapes Surgery across 4 Institutions.

OBJECTIVES: To investigate intra- and postoperative outcomes of endoscopic stapes surgery. STUDY DESIGN: Case series with chart review. SETTING: Four tertiary care otologic centers. SUBJECTS AND METHODS: Sixty-five subjects 18 years and older who underwent endoscopic stapes surgeries were analyzed. Variables analyzed included surgical techniques and intraoperative findings. Outcomes measured included postoperative hearing and complications to date. RESULTS: Fifty-one patients met inclusion and exclusion criteria. The average patient age was 48.1 years (range, 26-87 years), with 60.0% female patients. Patients had a median follow-up of 5.13 months (range, 0.8-57.4 months). Of the subjects, 71.7% required scutum removal. The chorda tympani nerve was manipulated in 94.0% of subjects and transected in 12.0%. At last follow-up visit, the median air-bone gap decreased from 34.5 dB hearing level (HL) preoperatively to 9.0 dB HL postoperatively (P < .0001). Ninety percent of subjects had closure of their air-bone gap ≤20 dB HL. Intraoperative complications included tympanic membrane tears in 8.0% of subjects, all of which resolved at first follow-up. Postoperatively, 10.0% of subjects complained of altered taste. CONCLUSIONS: The present multicentered study of endoscopic stapes surgery demonstrates similar audiometric and postoperative outcomes previously published in the literature, with a median postoperative air-bone gap of 9.0 dB HL. Future prospective endoscopic stapes surgery studies, addressing the need for scutum removal, postoperative taste changes, and pain scores, are merited.

Updates in anterior skull base reconstruction.

PURPOSE OF REVIEW: This article summarizes the indications and surgical techniques for the reconstructions of anterior skull base defects. RECENT FINDINGS: There is increasing popularity of the vascularized pedicled flaps in endoscopic skull base surgery for the successful reconstruction of anterior skull base defects, compared with the use of free-tissue grafts. The location and size of the defect as well as the rate of cerebrospinal fluid (CSF) flow are important considerations for selection of the most appropriate reconstructive approach. Recent literature provides evidence suggesting that pedicled flaps may be more effective for clival defects and high-flow CSF leaks, potentially reducing the incidence of postoperative CSF leaks. Although the nasoseptal flap (NSF) continues to be the mainstay of endoscopic skull base reconstruction, alternative vascularized flaps exist when the NSF is impractical or unavailable, and new surgical approaches continue to evolve. SUMMARY: Vascularized pedicled flaps, and especially the NSF, have greatly reduced complications associated with endoscopic skull base surgery. Multiple considerations should be taken into account during closure of skull base defects, and several options are available to accommodate different needs.