Radiographic Assessment and Surgical Implications of Arcuate Eminence Pneumatization.

BACKGROUND: The middle cranial fossa (MCF) approach is a valuable yet technically challenging technique. Identification of the superior semicircular canal (SCC) using the arcuate eminence (AE) was proposed as a surface landmark. However, the AE is sometimes absent, with inconsistent relationship to the SCC. Air cells in the AE area facilitate safer identification of the SCC. The aim of this study is to determine the radiographic prevalence of AE pneumatization. METHODS: Two hundred consecutive fine-cut temporal bone CT scans were retrospectively reviewed. The region of the petrosal bone at and above the level of the SCC dome was assessed for the presence of air cells, and graded 0 (no pneumatization) to 2 (well pneumatized). RESULTS: Four hundred temporal bones were studied. The average age was 49 years (range 18-89). Of all AE assessments, 47 (12%) were nonpneumatized, 62 (15%) partially pneumatized, and 291 (73%) well pneumatized. There was no significant correlation between patient age and pneumatization grade (p = 0.72). CONCLUSION: The SCC is a valuable landmark in MCF surgery as it holds consistent relationships to adjacent critical structures. Surrounding air cells should facilitate safer initial identification of the SCC, as the AE region is well pneumatized in 73% of patients.

Contemporary Neuroradiographic Assessment of the Cochleo-Carotid Partition.

PURPOSE: The cochleo-carotid partition (CCP) describes the intimate anatomic relationship between the petrous carotid artery and the cochlear basal turn. This partition bears significant surgical and unique clinical relevance. The purpose of this paper is to radiographically assess the CCP and discuss its clinical implications. METHODS: A total of 155 consecutive fine-cut temporal bone CT scans were retrospectively reviewed, and study scans were digitally analyzed in both axial and coronal views. The shortest distance between the petrous carotid canal and the cochlear basal turn was measured. RESULTS: In all, 310 temporal bones were studied, with a mean CCP of 1.9 mm (range 0.2-8.5, SD 1.1). The following CCP measurements were obtained: ≤1.0 mm [n = 46 (14.8%)]; 1.1-2.0 mm [n = 161 (51.9%)]; 2.1-3.0 mm [n = 29 (9.4%)], and ≥4.0 mm [n = 12 (4.2%)]. One temporal bone (0.3%) had complete CCP dehiscence. There was a positive correlation between each patient's right and left CCP measures (p < 0.005) and a significant negative correlation between CCP grade and age (p = 0.027). CONCLUSIONS: The CCP is a narrow anatomic confinement measuring ≤2 mm in 66.7% of patients. Potential implications of the CCP include iatrogenic risks, its possible function as a third inner ear window in patients with audiovestibular symptoms, and pathophysiology of new-onset tinnitus following cochlear implantation.

The cavernous sinus: An anatomic study with clinical implication.

Objective: The management of lesions involving the cavernous sinus remains a formidable challenge. To optimize care for patients with tumors extending into this skull base region a detailed understanding of the surrounding osteology as well as neural and vascular relationships is requisite. This thesis examines the gross anatomy of the region and highlights important surgical implications drawn from these as well as previously published studies. Methods: A review of the historical scientific, anatomic, clinical, and surgical literature extending to the present (1992) relating to the cavernous sinus has been performed and discussed. Additionally, the author has performed and described cadaveric dissections revealing novel details about the macroscopic (dural and neurovascular anatomic relationships) and microscopic structure of the cavernous sinus. A series of cases of cavernous sinus pathologies that were addressed in an interdisciplinary surgical approach at the author's institution is also reported. Results: Included in this report is a comprehensive review of the embryology of the cavernous sinus and its associated neurovascular structures. Cadaveric dissections have also revealed novel details about dural/meningeal compartments of the cavernous sinus as well as well as associated arterial, venous, and neural relationships. Microscopic observations also reveal novel fundamental insights into the components and structure of the cavernous sinus. Clinical examples from 20 patients illustrate the critical importance for clinical application of cavernous sinus anatomic knowledge to the surgical treatment of pathologies in this region. Conclusion: The cavernous sinus is a tripartite venous osteomeningeal compartment intimately neighboring vital structures including the optic tracts, pituitary gland, cranial nerves III, IV, V, V, VI, and the internal carotid artery. Surgical management of cavernous sinus lesions has and continues to evolve with increasing anatomic and clinical study as well as advancements in diagnostic and surgical methodologies. Level of Evidence: NA.

Evaluation of Current Triological Society Thesis Trends and Membership Demographics.

OBJECTIVES: (1) Identify the time required for completion, submission, and acceptance of a Triological Thesis and trends for thesis acceptance. (2) Determine the current Triological Society demographics and identify variances based on separated age groups of the current membership. STUDY DESIGN: Retrospective review of The Triological Society database and survey of candidates and fellows. METHODS: Data from the records of all candidates and fellows of the Triological Society were reviewed to determine the number of years from candidate to active fellow status for all members inducted into the Triological Society from 1990 to 2018. In addition, all current candidates, active and senior fellows were surveyed online to capture demographic data and opinions regarding the Triological Society. RESULTS: Since 1990, there has been a steady increase in the number of candidates and theses accepted. Of candidates successfully completing theses, 73% did so within 3 years and 90% within 5 years. Based on the 514 of 809 (64%) active and senior fellows responding to the survey, 83% reported being male and 15% female. Also, 73% reported as Caucasian, 12% Asian, 2% Hispanic, 2% Black, 0% Native American, and 2% Mixed Race. Of the 93 of 178 (52%) active candidates (those authorized to prepare a thesis) responding to the survey, 70% reported as male, 28% female, 58% Caucasian, 17% Asian, 6% Hispanic, 5% Black, 0% Native American, and 3% Mixed Race. CONCLUSIONS: The Triological Society continues to grow, and its membership is becoming more diverse, including more women and wider ethnic diversity. Candidates should plan for submitting their thesis as early as possible as data demonstrates the greatest likelihood of success if done within 3 years. LEVEL OF EVIDENCE: NA Laryngoscope, 133:73-78, 2023.

Quantification of Fat Graft Retention in the Translabyrinthine Approach Using Magnetic Resonance Imaging Volumetric Analysis.

OBJECTIVE: To characterize the viability and volume of autologous free fat grafts over time, determine clinical/patient factors that may affect free fat graft survival and assess the clinical impact of free fat graft survival on patient outcomes in the translabyrinthine approach for lateral skull base tumor resection. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary neurotologic referral center. PATIENTS: Forty-two adult patients who underwent translabyrinthine craniotomy for resection of a lateral skull base tumor with the mastoid defect filled by autologous abdominal fat graft and subsequently underwent more than one postoperative magnetic resonance imaging (MRI) scans of the brain. INTERVENTIONS: Mastoid obliteration with abdominal fat after craniotomy, postoperative MRI. MAIN OUTCOME MEASURES: Rate of fat graft volume loss, fraction retention of original fat graft volume, initial fat graft volume, time to steady-state fat graft retention, rate of postoperative cerebrospinal fluid (CSF) leak, and/or pseudomeningocele formation. RESULTS: Patients were followed postoperatively with MRI for a mean of 31.6 months with a mean of 3.2 postoperative MRIs per patient. Initial graft size was a mean of 18.7 cm3 with a steady-state fat graft retention of 35.5%. Steady-state graft retention (<5% loss per year) was achieved at a mean of 24.96 months postoperatively. No significant association was found in multivariate regression analysis of clinical factors impact on fat graft retention and CSF leak/pseudomeningocele formation. CONCLUSIONS: In the use of autologous abdominal free fat graft for filling mastoid defects after translabyrinthine craniotomy, there is a logarithmic decline in fat graft volume over time, reaching steady state in 2 years. Rates of CSF leak or pseudomeningocele formation were not significantly affected by initial volume of the fat graft, rate of fat graft resorption, nor the fraction of original fat graft volume at steady state. In addition, no analyzed clinical factors significantly influenced fat graft retention over time.

A proposed classification system for presigmoid approaches: a scoping review.

OBJECTIVE: The "presigmoid corridor" covers a spectrum of approaches using the petrous temporal bone either as a target in treating intracanalicular lesions or as a route to access the internal auditory canal (IAC), jugular foramen, or brainstem. Complex presigmoid approaches have been continuously developed and refined over the years, leading to great heterogeneity in their definitions and descriptions. Owing to the common use of the presigmoid corridor in lateral skull base surgery, a simple anatomy-based and self-explanatory classification is needed to delineate the operative perspective of the different variants of the presigmoid route. Herein, the authors conducted a scoping review of the literature with the aim of proposing a classification system for presigmoid approaches. METHODS: The PubMed, EMBASE, Scopus, and Web of Science databases were searched from inception to December 9, 2022, following the PRISMA Extension for Scoping Reviews guidelines to include clinical studies reporting the use of "stand-alone" presigmoid approaches. Findings were summarized based on the anatomical corridor, trajectory, and target lesions to classify the different variants of the presigmoid approach. RESULTS: Ninety-nine clinical studies were included for analysis, and the most common target lesions were vestibular schwannomas (60/99, 60.6%) and petroclival meningiomas (12/99, 12.1%). All approaches had a common entry pathway (i.e., mastoidectomy) but were differentiated into two main categories based on their relationship to the labyrinth: translabyrinthine or anterior corridor (80/99, 80.8%) and retrolabyrinthine or posterior corridor (20/99, 20.2%). The anterior corridor comprised 5 variations based on the extent of bone resection: 1) partial translabyrinthine (5/99, 5.1%), 2) transcrusal (2/99, 2.0%), 3) translabyrinthine proper (61/99, 61.6%), 4) transotic (5/99, 5.1%), and 5) transcochlear (17/99, 17.2%). The posterior corridor consisted of 4 variations based on the target area and trajectory in relation to the IAC: 6) retrolabyrinthine inframeatal (6/99, 6.1%), 7) retrolabyrinthine transmeatal (19/99, 19.2%), 8) retrolabyrinthine suprameatal (1/99, 1.0%), and 9) retrolabyrinthine trans-Trautman's triangle (2/99, 2.0%). CONCLUSIONS: Presigmoid approaches are becoming increasingly complex with the expansion of minimally invasive techniques. Descriptions of these approaches using the existing nomenclature can be imprecise or confusing. Therefore, the authors propose a comprehensive classification based on the operative anatomy that unequivocally describes presigmoid approaches simply, precisely, and efficiently.

Predictive Effect of Bone Conduction Pattern on Hearing Outcomes of Stapes Surgery.

OBJECTIVE: Examine the effect of preoperative bone conduction pattern on outcomes of stapedotomy/stapedectomy. STUDY DESIGN: Retrospective case series. SETTING: Tertiary-care academic medical center. PATIENTS: Patients who underwent stapedotomy or stapedectomy from 2013 to 2019. INTERVENTIONS: Primary small-fenestra stapedotomy or partial stapedectomy. MAIN OUTCOME MEASURES: Association between preoperative bone conduction patterns and hearing after stapes surgery. RESULTS: Complete audiometric data were available for 137 patients who had surgery. The mean preoperative air-bone gap (ABG) was 26.8 dBHL. The ABG was closed to less than 20 and 10 dBHL in 88.7 and 65.2% of patients, respectively. A notch at 2000 Hz was present in 32.1% of operated ears and was rarely found at other frequencies. There was no statistically significant association between the presence of a notch and hearing outcomes. The slope of the bone conduction line had no association with hearing outcomes, though an increased bone conduction PTA compared with the contralateral ear was associated with ABG closure less than 10 dBHL and overclosure (odds ratio: 2.14, p = 0.027 and odds ratio: 2.20, p = 0.04). CONCLUSION: In properly selected otosclerosis patients, depressions in bone conduction other than near 2000 Hz are rare and hearing outcomes are generally favorable regardless of the preoperative bone conduction pattern. Despite the association with otosclerosis, the presence of a notch at 2000 Hz is not associated with better hearing outcomes with surgery.

Middle Cranial Fossa Approach to Vestibular Schwannoma Resection in the Older Patient Population.

OBJECTIVE: Compare outcomes of middle cranial fossa approach (MCF) to vestibular schwannoma (VS) resection in patients 60 years of age and older to patients under 60. STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. PATIENTS: Charts of 216 consecutive VS patients over 18 years of age were reviewed to identify 67 patients who underwent MCF approach to VS resection between 2006 and 2017. INTERVENTION(S): Age at time of surgery. MAIN OUTCOME MEASURE(S): Measured outcomes included postoperative hearing results, facial nerve function, length of hospital stay, wound complications, cerebrospinal fluid leak, myocardial infarction, cerebrovascular accident, seizure, deep vein thrombosis, 30-day readmission, and return to operating room. RESULTS: Sixty-seven patients underwent VS resection via MCF approach including 16 patients > = 60 years (mean 64.4 SD 3.3) and 51 patients < 60 years (mean 45.7 SD 10.2). Between these two groups, there were no differences in sex, tumor laterality, tumor size (10.4 mm versus 9.8 mm, p = 0.6), or other demographic characteristics. Postoperatively, there were no differences between groups in complication rates. Rates of HB 1 or 2 facial nerve function were similar (93.8% versus 88.2%, p = 0.7) as were rates of maintenance of class A or B hearing (58.3% versus 44.4%, p = 0.7). CONCLUSIONS: Patients over 60 undergoing MCF for VS resection experienced similar rates of postoperative complications, facial nerve outcomes, and hearing preservation compared with younger patients. MCF for VS may be considered in the older population. Further research is warranted to evaluate appropriate limitations for this approach based on age.

Extended Anterior Petrosectomy Through the Transcranial Middle Fossa Approach and Extended Endoscopic Transsphenoidal-Transclival Approach: Qualitative and Quantitative Anatomic Analysis.

BACKGROUND: Petroclival tumors and ventrolateral lesions of the pons present unique surgical challenges. This cadaveric study provides qualitative and quantitative anatomic comparison for an anterior petrous apicectomy through the transcranial middle fossa (TMF) and expanded endoscopic transsphenoidal-transclival approaches. METHODS: In 10 silicone-injected heads, the petrous apex and clivus were drilled extradurally using middle fossa and endonasal approaches. With in situ and frameless stereotactic navigation, we defined consistent points to compare working areas, bone removal volumes, approach angles, and surgical freedom. RESULTS: Mean exposed TMF area (21.03 ± 3.46 cm2) achieved a 44.71 ± 4.13° working angle to the brainstem between cranial nerves V and VI. Kawase's rhomboid area measured 1.76 ± 0.34 cm2, and bone removal averaged 1.20 ± 0.12 cm3 at the petrous apex. Surgical freedom on the lateral brainstem was higher halfway between cranial nerves V and VI at the center of the rhomboid compared with midline at the basilar sulcus (P < 0.01). After clivectomy and petrous apicectomy, mean exposed expanded endoscopic transsphenoidal-transclival area was 5.29 ± 0.66 cm2. Approach from either nostril showed no statistically significant differences in surgical freedom at the foramen lacerum and midpoint basilar sulcus. At the petrous apex, bone volume removed and area exposed were significantly larger for the TMF approach (P < 0.001). CONCLUSIONS: Expanded transclival anterior petrosectomy through the TMF approach provides an adequate corridor to lesions in the upper ventrolateral pons. The expanded endoscopic transsphenoidal-transclival approach better fits midline lesions not extending laterally beyond cranial nerve VI and C3 carotid when evaluating normal anatomic parameters.

Is Longer Surgery More Dangerous? Operative Duration Not Associated With Complications After Vestibular Schwannoma Resection.

OBJECTIVE: To examine the association between operative duration and complications after vestibular schwannoma (VS) surgery. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral center. PATIENTS: One hundred forty-eight patients undergoing vestibular schwannoma resection in a single institution. INTERVENTION: Vestibular schwannoma resection. MAIN OUTCOME MEASURES: Operative duration, surgical approach, tumor size, and postoperative complications. RESULTS: Forty-one patients underwent middle cranial fossa (MCF) approach, 46 underwent translabyrinthine (TL) approach, and 61 underwent retrosigmoid (RS) approach. The mean operative duration overall was 407 minutes (MCF-339 min, TL-450 min, RS 420 min). When controlling for tumor size, there was no difference in procedure duration by approach (OR 0.92, CI 0.82-1.02, p=0.11).When controlling for approach, there was a significant increase in procedure duration by tumor size (OR 1.36, CI 1.23-1.50, p < 0.0001). Increased procedure duration was not associated with 30-day readmission (p = 0.82), cerebrospinal fluid leak (CSF) (p = 0.84), return to the operating room (p = 0.75), postoperative deep vein thrombosis (p = 1.0), postoperative stroke (p = 0.23), or postoperative wound complications (p = 0.70). Longer operative time was associated with increased hospital length of stay (p = 0.04). However, when controlling for tumor size and surgical approach, hospital length of stay was no longer associated with increased procedure duration (OR 1.15, CI 0.98-1.33, p = 0.3). CONCLUSION: Increased operative duration was associated with larger tumor size; however contrary to previous reports, increased operative duration was not associated with postoperative complications.

Early Experience With Telemedicine in Patients Undergoing Otologic/Neurotologic Procedures.

OBJECTIVE: Compare outcomes for patients who were seen via telemedicine visits after otology/neurotology surgical procedures with those who were seen in traditional office visits. STUDY DESIGN: Retrospective case review. SETTING: Tertiary care academic medical center. PATIENTS: Inclusion criteria were patients who underwent otologic/neurotologic surgery and were seen in at least one telemedicine visit for postoperative care. INTERVENTION (S): Telemedicine visit for postoperative care. MAIN OUTCOME MEASURE (S): Comparison of the number of patient calls, unplanned visits, and delayed complications between telemedicine patients and controls matched for age, procedure, and American Society of Anesthesiologists (ASA) status. RESULTS: Eighteen patients were seen in telemedicine visits postoperatively after the following otologic/neurotologic surgical procedures: cochlear implant surgery (10), vestibular schwannoma resection (4), combined middle fossa and transmastoid cerebrospinal fluid (CSF) leak repair (2), middle fossa repair of superior canal dehiscence (1), and stapedectomy (1). All telehealth visits were for the second postoperative visit. The mean number of patient calls after surgery was 2.3 for the telemedicine group and 1.9 for matched controls which was not a statistically significant difference (p = 0.466). Both groups each had two patients who went to the emergency room, with one in each group being admitted. There was one delayed complication in the control group. CONCLUSION: Our preliminary experience suggests telemedicine may be used safely in caring for patients after otologic/neurotologic surgery, though it may be associated with more patient phone calls. Further study and experience, including assessing patient satisfaction, will clarify the future role of telemedicine in otology and neurotology.

Is Hard Failure Still a Common Indication for Revision Surgery in Adult Cochlear Implant Recipients?

OUTCOME OBJECTIVES: STUDY DESIGN:: Retrospective chart review. SETTING: Single tertiary care center, 2001 to 2016. PATIENTS: Adult CI recipients were assessed. Inclusion required ≥1 revision surgeries, operative note(s), and postrevision follow-up of 6 months. INTERVENTIONS: Therapeutic/rehabilitative. MAIN OUTCOMES MEASURES: Indications for revision (HF, SF, WC, and MM) were tabulated. The incidence of each was compared between cohorts implanted before/after 2011. Additional outcomes included implant usage, explantation rates, and postrevision speech scores. RESULTS: Four hundred thirty-two patients received 512 CIs. Of these, 30 patients required 38 revisions. Median time to revision was 24.5 months. Frequency by indication was HF (n = 14), SF (n = 12), WC (n = 8), and MM (n = 4). The overall revision rate was 7.4%. There was a significant decline in overall revisions for patients implanted before/after 2011 (10.4 versus3.5%; p = 0.009). No patients implanted after 2011 experienced a HF (p = 0.002). Patients with WC/MM had significantly shorter time to revision compared with patients with HF/SF (p = 0.04). The overall median follow-up was 24 months. Twenty-three of 30 patients are still using their revised CI. Patients revised for HF and MM achieved the best outcomes. CONCLUSION: 7.4% of adult CI recipients required revision surgery. Explantation/immediate reimplantation was an effective management strategy. While HF was the most common indication overall, no patients implanted after 2011 have suffered this complication. The overall revision rate has significantly declined since 2011.

Application of Ultrasonic Bone Aspirator for Decompression of the Internal Auditory Canal via the Middle Cranial Fossa Approach.

OBJECTIVE: Evaluate the safety and efficacy of the ultrasonic bone aspirator (UBA) during middle cranial fossa (MCF) approach to vestibular schwannoma (VS). STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. PATIENTS: Charts of 192 consecutive VS patients over 18 years of age were reviewed to identify 65 patients who underwent MCF approach to VS resection between 2006 and 2017. A combination of UBA and high-speed drill (HSD) was used to decompress the internal auditory canal (IAC) in 25 patients and HSD alone was used in the other 40 patients. INTERVENTION(S): Use of UBA during vestibular schwannoma surgery via MCF approach for decompression of the IAC. MAIN OUTCOME MEASURE(S): Postoperative facial nerve outcomes assessed by the House-Brackmann (HB) facial nerve grading scale. Rates of gross total resection (GTR) and cerebrospinal fluid (CSF) leak. RESULTS: There were no significant differences in postoperative facial nerve function, in rate of GTR of tumor, or in rate of CSF leak. In the UBA group 24/25 (96%) had postoperative HB grade I-II compared with 36/40 (90%) in the HSD group (p-value = 0.66). GTR was achieved in 25/25 (100%) in the UBA group compared with 38/40 (95%) in the HSD group (p-value = 1). In the UBA group, there were 0/25 (0%) cases of CSF leak compared with 1/40 (2.5%) in the HSD group (p-value = 1). CONCLUSIONS: UBA use is a safe and effective alternative or adjunct to HSD during MCF approach to expose the IAC contents. This surgical tool allows for bone removal with low risk of injury to adjacent structures.

Cerebrospinal Fluid Leak Rate after Vestibular Schwannoma Surgery via Middle Cranial Fossa Approach.

Objective Evaluate the cerebrospinal fluid (CSF) leak rate after the middle cranial fossa (MCF) approach to vestibular schwannoma (VS) resection. Design Retrospective case series. Setting Quaternary referral academic center. Participants Of 161 patients undergoing the MCF approach for a variety of skull base pathologies, 66 patients underwent this approach for VS resection between 2007 and 2017. Main Outcome Measure Postoperative CSF leak rate. Results There were two instances of postoperative CSF leak (3.0%). Age, gender, and BMI were not significantly associated with CSF leak. In the two cases with CSF leakage, tumors were isolated to the internal auditory canal (IAC) and both underwent gross total resection. Both CSF leaks were successfully treated with lumbar drain diversion. For the 64 cases that did not have a CSF leak, 51 were isolated to the IAC, 1 was located only in the cerebellopontine angle (CPA), and 12 were located in both the IAC and CPA. 62 patients underwent gross total resection and 2 underwent near-total resection. Mean maximal tumor diameter in the CSF leak group was 4.5 mm (range: 3-6 mm) versus 10.2 mm (range: 3-19 mm) in patients with no CSF leak ( p = 0.03). Conclusions The MCF approach for VS resection is a valuable technique that allows for hearing preservation and total tumor resection and can be performed with a low CSF leakage rate. This rate of CSF leak is less than the reported rates in the literature in regard to both translabyrinthine and retrosigmoid approaches.

Utility of Magnetic Resonance Imaging in Differentiating Cerebrospinal Fluid Leak from Middle Ear Effusion.

OBJECTIVE: To demonstrate the clinical utility, sensitivity, and specificity of standard magnetic resonance imaging (MRI) sequences in differentiating temporal bone cerebrospinal fluid leaks from all other middle ear effusions. STUDY DESIGN: Retrospective imaging review. SETTING: Academic medical center. SUBJECTS: Patients with cerebrospinal fluid leaks or other middle ear effusions who also underwent MRI. METHODS: Patients were assigned to cerebrospinal fluid leak and other effusion cohorts based on clinical course, findings at surgery/myringotomy, and beta-2 transferrin fluid analysis. Reviewers blinded to the clinical outcome examined T1-weighted, T2-weighted, diffusion-weighted, fluid-attenuated inversion recovery (FLAIR), and 3-dimensional (3D) acquired T2-weighted MRI sequences. For each sequence, fluid imaged in the temporal bone was graded as either similar or dissimilar in signal intensity to cerebrospinal fluid in the adjacent subarachnoid space. Signal similarity was interpreted as being diagnostic of a leak. Test characteristics in predicting the presence of a leak were calculated for each series. RESULTS: Eighty patients met criteria (41 leaks, 39 other effusions). The 3D T2 series was 76% sensitive and 100% specific in diagnosing a leak, and FLAIR was 44% sensitive and 100% specific. The T1-weighted (73% sensitive, 69% specific), T2-weighted (98% sensitive, 5.1% specific), and diffusion-weighted (63% sensitive, 66% specific) series were less useful. CONCLUSIONS: MRI, with attention to 3D T2 and FLAIR series, is a noninvasive and highly specific test for diagnosing cerebrospinal fluid leak in the setting of an indeterminate middle ear effusion.

Obesity Is Not Associated With Postoperative Complications After Vestibular Schwannoma Surgery in a Large Single Institution Series.

OBJECTIVE: Determine whether elevated body mass index (BMI) is associated with postoperative complications after vestibular schwannoma (VS) surgery. STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. PATIENTS: Two hundred six patients undergoing surgery for VS between 2010 and 2017, grouped into obese and nonobese patients. INTERVENTION: Surgery for VS resection. MAIN OUTCOME MEASURES: Postoperative facial nerve outcomes, length of hospital stay, presence of postoperative cerebrospinal fluid leak, 30-day readmission, return to the operating room, wound complications, cardiovascular and thromboembolic complications. RESULTS: After excluding 1 patient for missing BMI, our cohort included 205 patients. Seventy-nine patients (38.5%) were obese (mean BMI 36.2 kg/m, range 30-55.1) and the remaining 126 (61.5%) were nonobese (mean BMI 25.0, range 18.8-29.8 kg/m). Compared with nonobese patients, obesity was not associated with postoperative cerebrospinal fluid leak (OR 1.1, 95% CI 0.93-1.1), length of hospital stay (OR 0.98, 95% CI 0.65-1.47), 30-day readmission rates (1.04, 95% CI 0.95-1.14), return to operating room (OR 1.05, 95% CI 0.98-1.11), or other wound-related complications (OR 0.99, 95% CI 0.94-1.04). CONCLUSION: In this cohort, elevated BMI was not associated with an increased risk for postoperative complications after VS surgery. Our findings may mitigate concerns associated with surgical management of VS in obese patients.

Evolution in the assessment and management of trigeminal schwannoma.

EDUCATIONAL OBJECTIVE: At the conclusion of this presentation, the participants should be able to understand the contemporary assessment and management algorithm used in the evaluation and care of patients with trigeminal schwannomas. OBJECTIVES: 1) Describe the contemporary neuroradiographic studies for the assessment of trigeminal schwannoma; 2) review the complex skull base osteology involved with these lesions; and 3) describe a contemporary management algorithm. STUDY DESIGN: Retrospective review of 23 cases. METHODS: Chart review. RESULTS: From 1984 to 2006, of 23 patients with trigeminal schwannoma (10 males and 13 females, ages 14-77 years), 15 patients underwent combined transpetrosal extirpation, 5 patients underwent stereotactic radiation, and 3 were followed without intervention. Of the 15 who underwent surgery, total tumor removal was achieved in 9 patients. Cytoreductive surgery was performed in six patients; of these, four received postoperative radiation. One patient who underwent primary radiation therapy required subsequent surgery. There were no deaths in this series. Cranial neuropathies were present in 14 patients pretreatment and observed in 17 patients posttreatment. Major complications included meningitis (1), cerebrospinal fluid leakage (2), major venous occlusion (1), and temporal lobe infarction (1). CONCLUSIONS: Trigeminal schwannomas are uncommon lesions of the skull base that may occur in the middle fossa, posterior fossa, or both. Moreover, caudal extension results in their presentation in the infratemporal fossa. Contemporary diagnostic imaging, coupled with selective use of both surgery and radiation will limit morbidity and allow for the safe and prudent management of this uncommon lesion.

Contemporary role of endolymphatic mastoid shunt surgery in the era of transtympanic perfusion strategies.

OBJECTIVES: Although there exist undisputed methods to permanently silence the aberrant end organ, controversy surrounds the durable efficacy of non-ablative interventions. This study provides a contemporary review of our institution's clinical experience in performing endolymphatic mastoid shunt surgery (EMSS) in patients with medically refractory endolymphatic hydrops, or Meniere's disease. METHODS: Between 1984 and 2002, 1,612 patients were referred to our institution with a diagnosis of Meniere's disease. Of these referrals, 1,172 patients met the criteria for Meniere's disease. Although 553 patients responded to medical management, 486 patients underwent EMSS and 133 patients had refractory disease that required chemical or surgical obliterative interventions. The retrospective study utilizes data collected on 226 patients who were followed for a minimum of 5 years. RESULTS: Overall, 78% patients responded favorably to EMSS, according to the functional level scale and class categories delineated by the American Academy of Otolaryngology-Head and Neck Surgery 1995 guidelines for control of vertigo. According to the Arenberg anatomic classification for endolymphatic sac location, EMSS achieved adequate control of vertigo in 86% of type I cases, 90% of type II cases, and 82% of type III cases. CONCLUSIONS: Endolymphatic mastoid shunt surgery is a relatively safe, effective procedure for the long-term control of vertigo in patients with medically refractory Meniere's disease.

Are Patients with Spontaneous CSF Otorrhea and Superior Canal Dehiscence Congenitally Predisposed to Their Disorders?

Objectives (1) Compare lateral skull base (LSB) height/thickness in patients with spontaneous cerebrospinal fluid otorrhea (CSF), superior canal dehiscence (SCD), acoustic neuromas (AN), and otosclerosis (OTO). (2) Perform correlations between age, body mass index (BMI), sex, and LSB height/thickness. Study Design Case series with chart review. Setting Tertiary referral center. Subjects and Methods Patients with CSF, SCD, AN, and OTO diagnosed from 2006 to 2016 were included if they had high-definition temporal bone computed tomography (CT) and absence of trauma, radiation, chronic ear disease, and/or congenital anomaly. CT-based measurements included LSB height/thickness and pneumatization rates overlaying the external auditory canal (EAC), tegmen tympani (TgT), perigeniculate region (PG), and internal auditory canal (IAC). LSB height/thickness, age, sex, and BMI were statistically correlated. In total, 256 patients and 493 ears (109 CSF, 115 SCD, 269 AN/OTO) were measured. Results Patients with CSF had significantly higher BMIs than the other groups ( P < .001). Patients with CSF and SCD had similar radiographic LSB phenotypes at most measured locations. Both groups exhibited a significantly lower LSB height compared to the AN and OTO groups (mean, 3.9-4.2 mm vs 4.9-5.6 mm; P < .001). Patients with CSF and SCD also demonstrated significantly lower pneumatization rates, as low as 17% to 23% overlaying the PG and IAC ( P < .001). There were no statistically significant correlations found between age, sex, BMI, and LSB height/thickness at any measurement location in any group. Conclusions Patients with CSF and SCD exhibit similar radiographic LSB phenotypes. Age, sex, and BMI do not significantly correlate with LSB height/thickness. These data support the theory that CSF and SCD arise via similar congenital pathoetiologic mechanisms.

Use of a novel ultrasonic surgical system for decompression of the facial nerve.

OBJECTIVE: The middle cranial fossa approach has been used to explore and decompress the facial nerve in patients with Bell's palsy and facial nerve tumors. Unfortunately, this approach is technically challenging and has a significant risk of injury to the facial nerve and to the cochleovestibular organs. One way to minimize the risk may be with the use of the Sonopet Omni ultrasonic aspirator (Synergetics Inc., St Charles, MO) instead of an otologic drill. METHODS: In this prospective study using cadaveric temporal bones, a total of 17 temporal bone specimens were used. Seven cadaveric temporal bones were used (4-left, 3-right) for the initial feasibility study. At a second session, an additional 10 temporal bones (5-left, 5-right) underwent decompression of the facial nerve from the fundus of the internal auditory canal (IAC) to the geniculate ganglion (ie, labyrinthine segment). The average time to decompress the labyrinthine segment was measured. The temporal bones were then examined for evidence of any injury. RESULTS: None of the 17 temporal bones showed any sign of injury to the superior semicircular canal or the cochlea. However, one specimen did have penetration of the IAC dura; another specimen did have penetration of the epineurium of the facial nerve. However, in neither case was there any evidence of injury to the facial nerve itself. At the first session, the average time for decompression of the labyrinthine segment was 10 minutes and 12 seconds. At the second session, the average time for decompression was 5 minutes and 0 seconds. CONCLUSION: The ultrasonic surgical system may be used as an alternative to the surgical drill for decompression of the facial nerve. Although a learning curve does exist, as with any new surgical tool or device, our results indicate that the device can be used safely and in a reasonable amount of time. However, before proceeding with intraoperative use of this device for otologic and neurotologic procedures, familiarization is first recommended on cadaveric temporal bone specimens.