Giant skull base collision tumors in neurofibromatosis type 2–related schwannomatosis (NF2-SWN) pose a complex surgical challenge in young patients with lifelong tumor burden. Gross total resection is often impossible without severe neurological morbidity, and data on operative timing and durability are limited. We assessed long-term outcomes of planned, selective resection prioritizing neurological preservation. We queried a prospective institutional database for NF2-SWN patients undergoing surgery for giant (≥ 4.0 cm) intracranial skull base collision tumors (≥ 2 neoplasms forming one mass) from January 2009 to December 2025. Surgery targeted symptomatic or high-risk components, accepting residual disease. Outcomes included time to reoperation, overall survival, and functional status. Thirteen patients underwent 31 skull base operations. Mean age at first surgery was 27 years (range 19–42), with mean tumor diameter 5.0 cm (range 4.0–7.7 cm). Most (69

Purpose NF2 -related schwannomatosis (NF2) is characterized by bilateral vestibular schwannomas (VS) often causing hearing and neurologic deficits, with currently no FDA-approved drug treatment. Pre-clinical studies highlighted the potential of mTORC1 inhibition in delaying schwannoma progression. We conducted a prospective open-label, phase II study of everolimus for progressive VS in NF2 patients and investigated imaging as a potential biomarker predicting effects on growth trajectory. Methods The trial enrolled 12 NF2 patients with progressive VS. Participants received oral everolimus daily for 52 weeks. Brain imaging was obtained quarterly. As primary endpoint, radiographic response (RR) was defined as ≥ 20% decrease in target VS volume. Secondary endpoints included other tumors RR, hearing outcomes, drug safety and quality of life (QOL). Results Eight participants completed the trial and four discontinued the drug early due to significant volumetric VS progression. After 52 weeks of treatment, the median annual VS growth rate decreased from 77.2% at baseline to 29.4%. There was no VS RR and 3 of 8 (37.5%) participants had stable disease. Decreased or unchanged VS volume after 3 months of treatment was predictive of stabilization at 12 months. Seven of eight participants had stable hearing during treatment except one with a decline in word recognition score. Ten of twelve participants reported only minimal changes to their QOL scores. Conclusions Volumetric imaging at 3 months can serve as an early biomarker to predict long-term sensitivity to everolimus treatment. Everolimus may represent a safe treatment option to decrease the growth of NF2-related VS in patients who have stable hearing and neurological condition. TRN: NCT01345136 (April 29, 2011).

OBJECTIVE:To evaluate the safety of 3 Tesla (T) magnetic resonance imaging (MRI) in patients with auditory brainstem implants (ABI) with the magnet removed at implantation and report incidence of complications.STUDY DESIGN:Retrospective chart review.SETTING:Tertiary neurotology ambulatory practice.PATIENTS:Patients with diagnosis of Neurofibromatosis, type 2 (NF2) with functional ABIs.INTERVENTIONS:Observational recordings.MAIN OUTCOME MEASURES:Of the 89 patients meeting inclusion criteria, 7 patients underwent 3T MRI, with a total of 39 scans done. Three patients had 1 scan each, one patient had 4 scans, one patient had 5 scans, one patient had 6 scans, and one patient had 21 scans. The mean time between ABI placement and first 3 T scan was 118 ± 73 months. The most common indication for imaging was surveillance of NF2 lesions. The most frequent scans were MRI brain (25.6%), followed by MRI of cervical (15%), thoracic (15%) and lumbar (15%) spine, and MRI IAC (8%). There were no reported complications for any of the scans. No scans were interrupted due to patient discomfort. There were no device malfunctions.CONCLUSIONS:3 T MRIs are safe in patients with ABIs as long as the magnet is removed. It is recommended that the magnet be removed at the time of implantation in all NF2 patients, who require frequent surveillance.

OBJECTIVE Cerebellopontine angle (CPA) meningioma can affect hearing function and require expeditious treatment to prevent permanent hearing loss. The authors sought to determine the factors associated with hearing functional outcome in CPA meningioma patients treated with surgery and/or radiation therapy either stereotactic radiosurgery or stereotactic radiation therapy. METHODS Consecutive patients with CPA meningioma who had presented at our hospital from 2008 to 2018 were identified through retrospective chart review. Hearing function-pure tone audiogram (PTA) and speech discrimination score (SDS)-was assessed before and after surgery for CPA meningioma. Hearing function with PTA>50 dB and SDS<69% were defined as poor hearing functional outcome. Multivariable Cox Proportional Hazards Regression model was used to assess the associations between pre-operative hearing functional assessment and post-operative hearing functional outcomes. RESULTS The study cohort included 31 patients (80.6% females, with a mean age of 61.3±15.2 years) with a median clinical follow-up of 5 months (range, 1 week-98 months). The mean pre-operative PTA and SDS were 23.8±11.2 dB and 64.4±22.2% respectively. At the last visit, there was a significant hearing recovery, with an improvement of 29.7±18.0 dB (p<0.001) and 87.6±17.8% (p<0.001) in PTA and SDS respectively. Multivariable cox proportional hazards regression model was conducted after adjusting for age, gender, tumor volume, location, and classification of the tumor, which revealed that patients undergoing surgery through retro sigmoid approach [Hazards Ratio (HR): 32.1, 95% Confidence Interval (CI): 2.11-491.0, p=0.01] and gross total resection (GTR) (HR: 2.99, 95%CI: 1.09-9.32, p=0.05) had significantly higher risk of poor hearing functional outcome. Moreover, patients with poor preoperative hearing had 85% higher chances of poor hearing functional outcome post operatively (HR: 0.15, 95%CI: 0.03-0.59, p=0.007). CONCLUSION Postoperative improvement in hearing is a reasonable expectation following surgery for CPA meningioma. Preoperative hearing, surgical approach and extent of surgical resection are predictive of postoperative hearing function outcome and can identify patients at higher risk of hearing loss.

Objective Data regarding the surgical advantages and anatomic constraints of a hearing-preserving endoscopic-assisted retrolabyrinthine approach to the IAC are scarce. This study aimed to define the minimum amount of retrosigmoid dural exposure necessary for endoscopic exposure of the IAC and the surgical freedom of motion afforded by this approach. Methods Presigmoid retrolabyrinthine approaches were performed on fresh cadaveric heads. The IAC was exposed under endoscopic guidance. The retrosigmoid posterior fossa dura was decompressed until the fundus of the IAC was exposed. Surgical freedom of motion at the fundus was calculated after both retrolabyrinthine and translabyrinthine approaches. Results The IAC was entirely exposed in nine specimens with a median length of 12mm (range: 10-13mm). Complete IAC exposure could be achieved with 1cm of retrosigmoid dural exposure in eight of nine mastoids. For the retrolabyrinthine approach, the median anterior-posterior surgical freedom was 13degrees (range: 6-23degrees) compared with 46degrees (range: 36-53degrees) for the translabyrinthine approach ( p =0.014). For the retrolabyrinthine approach, the median superior-inferior surgical freedom was 40degrees (range 33-46degrees) compared with 47degrees (range: 42-51degrees) for the translabyrinthine approach ( p =0.022). Conclusion Using endoscopic assistance, the retrolabyrinthine approach can expose the entire IAC. We recommend at least 1.5cm of retrosigmoid posterior fossa dura exposure for this approach. Although this strategy provides significantly less instrument freedom of motion in both the horizontal and vertical axes than the translabyrinthine approach, it may be appropriate for carefully selected patients with intact hearing and small-to-medium sized tumors involving the IAC.

OBJECTIVE:To discuss indications for bilateral auditory brainstem implants (ABIs), compare audiometric outcomes of unilateral vs bilateral ABIs, and determine if patients have improved outcomes with addition of a second-side implant.STUDY DESIGN:Retrospective review of 24 patients with neurofibromatosis 2 (NF2) who underwent sequential placement of ABIs from 1989 to 2019.SETTING:Tertiary referral center.METHODS:Charts were reviewed for indication for second-side surgery, use of implants, and audiometric outcomes. Implants placed in the past 30 years were included in the study. Northwestern University Children's Perception of Speech (NU-CHIPS) and/or City University of New York (CUNY) sentence scores were compared in unilateral and bilateral conditions.RESULTS:Indications for a second-side implant included first-side implants with severe nonauditory symptoms (11), marginal audiometric results (9), outdated technology (2), or deterioration of first side (2). Seven patients are bilateral users and 1 patient discontinued bilateral use after a year due to no significant improvement over unilateral use. One patient with initial bilateral use was lost to follow-up. Thirteen patients are unilateral users due to nonaudiometric side effects or poor audiometric outcomes with the first side. Two patients are complete nonusers. Seventy-five percent had improved audiometric outcomes after the second-side implant, and 20% had stable findings.CONCLUSIONS:Second-side ABIs should be consider in patients with poor performance from a first-side implant. Most patients demonstrate subjective improvement with the second ABI. More research is needed for better objective assessments of improvements.

OBJECTIVE:Patients with vestibular schwannoma who harbor a genetic predisposition for venous thromboembolism require special consideration when determining optimal therapeutic management. The primary objective of the current study was to provide recommendations on treatment of hypercoagulable patients with vestibular schwannoma through a case series and review of the literature.PATIENTS:Two patients who underwent resection of vestibular schwannomas.INTERVENTIONS:Surgical resection and diagnostic testing.MAIN OUTCOME MEASURES:Postoperative venous thromboses.RESULTS:One patient who underwent resection of vestibular schwannoma and suffered several postoperative thrombotic complications consistent with a clinical thrombophilia. One patient with known Factor V Leiden deficiency who underwent resection of vestibular schwannoma followed by postoperative chemoprophylaxis with a direct factor Xa inhibitor and experienced an uneventful postoperative course.CONCLUSIONS:In patients with a known propensity for venous thromboembolism, the skull base surgeon should consider nonsurgical management. If the patient undergoes surgical resection, we recommend careful effort to minimize trauma to the sigmoid sinus. In addition, the surgeon may consider retrosigmoid or middle fossa approaches. Best practice recommendations include the use of pneumatic compression devices, early ambulation, and consideration of postoperative prophylactic anticoagulation in patients with a known genetic predisposition.

INTRODUCTION:Malignancies involving the temporal bone are increasingly common and require specialized multi-disciplinary care. Given this complex location, involvement of the lateral skull base and local neurovascular structures is common. In this review we discuss general principles for temporal bone resection, as well as alternative and complementary surgical approaches that should be considered in the management of patients with temporal bone cancer.METHODS:A comprehensive review on literature pertaining to temporal bone resection was performed.RESULTS:The primary surgical strategy for malignancies of the temporal bone is temporal bone resection. This may be limited to the ear canal and tympanic membrane (lateral temporal bone resection) or may include the otic capsule and its contents (subtotal temporal bone resection), and/or the petrous apex (total temporal bone resection). Management of adjacent neurovascular structures including the facial nerve, the carotid artery, and the jugular bulb/sigmoid sinus should be considered during surgical planning. Finally, adjunctive procedures such as parotidectomy and neck dissection may be required based on tumor stage.CONCLUSIONS:Temporal bone resection is an important technique in the treatment of lateral skull-base malignancies. This strategy should be incorporated into a multi-disciplinary approach to cancer.

Objective:To provide long-term follow up of a unique patient with history of massive petrous apex congenital cholesteatoma.Patient:75-year-old man who presented at age 18 with left Gradenigo-like syndrome.Intervention:Staged left radical mastoidectomy and open transsphenoidal marsupialization. Followed with routine in-office cholesteatoma debridement.Main Outcome Measures:Bony erosion on computed tomography (CT), monitoring for new symptoms.Results:Interval development of sensorineural component of hearing loss due to cochlear fistulization. Very slow skull base bony erosion continues without neck destabilization. No new or recurrent cranial neuropathies have developed.Conclusions:Marsupialized cholesteatoma may be followed with routine debridement and interval imaging for monitoring over many decades.

Radiation-induced sarcoma is a known but rare complication of radiation treatment for skull base paraganglioma. We present the cases of a female patient with multiple paraganglioma syndrome treated with external beam radiation treatment who presented 4 years later with a malignant peripheral nerve sheath tumor of the vagus nerve.

Objective: To address variance in clinical care surrounding sporadic vestibular schwannoma, a modified Delphi study was performed to establish a general framework to approach vestibular schwannoma care. A multidisciplinary panel of experts was established with deliberate representation from key stakeholder societies. External validity of the final statements was assessed through an online survey of registered attendees of the 8th Quadrennial International Conference on Vestibular Schwannoma. Study Design: Modified Delphi method. Methods: The panel consisted of 16 vestibular schwannoma experts (8 neurotology and 8 neurosurgery) and included delegates representing the AAOHNSF, AANS/CNS tumor section, ISRS, and NASBS. The modified Delphi method encompassed a four-step process, comprised of one prevoting round to establish a list of focus areas and three subsequent voting rounds to successively refine individual statements and establish levels of consensus. Thresholds for achieving moderate consensus, at >= 67% agreement, and strong consensus, at >= 80% agreement, were determined a priori. All voting was performed anonymously via the Qualtrics online survey tool and full participation from all panel members was required before procession to the next voting round. Results: Through the Delphi process, 103 items were developed encompassing hearing preservation (N = 49), tumor control and imaging surveillance (N = 20), preferred treatment (N = 24), operative considerations (N = 4), and complications (N = 6). As a result of item refinement, moderate (4%) or strong (96%) consensus was achieved in all 103 final statements. Seventy-nine conference registrants participated in the online survey to assess external validity. Among these survey respondents, moderate (N = 21, 20%) or strong (N = 73, 71%) consensus was achieved in 94 of 103 (91%) statements, and no consensus was reached in 9 (9%). Of the four items with moderate consensus by the expert panel, one had moderate consensus by the conference participants and three had no consensus. Conclusion: This modified Delphi study on sporadic vestibular schwannoma codifies 100% consensus within a multidisciplinary expert panel and is further supported by 91% consensus among an external group of clinicians who regularly provide care for patients with vestibular schwannoma. These final 103 statements address clinically pragmatic items that have direct application to everyday patient care. This document is not intended to define standard of care or drive insurance reimbursement, but rather to provide a general framework to approach vestibular schwannoma care for providers and patients.

Objective To provide the first description of hypofractionated stereotactic radiosurgery (SRS) and evaluate tumor control and safety for vagal paragangliomas (VPs), which begin at the skull base but often have significant extracranial extension. Study Design Retrospective chart review. Setting Tertiary-referral neurotology and neurosurgery practice. Subjects and Methods Five VPs in 4 patients (all male, ages 15-56 years) underwent SRS between 2010 and 2018. Outcome measures included tumor dimensions on serial imaging, cranial nerve function, and radiation side effects. Results CyberKnife hypofractionated SRS was performed. The prescription dose was 24 or 27 Gy (maximum dose 33.4 Gy; range, 29.3-35.5 Gy) delivered in 3 equal fractions. The mean isodose line was 79% (range, 76%-82%). Four VPs were treated primarily, and 1 tumor underwent SRS to treat regrowth 2 years after microsurgical subtotal resection via the modified infratemporal fossa approach. The treatment volume ranged from 8.81 to 86.3 cm3 (mean, 35.7 cm3). All demonstrated stable size (n = 3) or regression (n = 2) at last follow-up, 63 to 85 months after SRS (mean, 76 months). One patient had stable premorbid vocal fold paralysis from a prior ipsilateral glomus jugulare tumor resection. All others demonstrated normal vagal function following SRS. Treatment-related side effects, including dysgeusia (n = 1), mucositis (n = 1), and neck soft-tissue edema (n = 2), were self-limited. Conclusions Hypofractionated SRS appears to be both safe and effective for treating VPs, including large-volume and predominantly extracranial tumors, while preserving vagal function. SRS should be considered as a cranial nerve preservation option, especially in settings of contralateral lower cranial nerve deficits or in those with multiple paragangliomas risking both vagal nerves.

Objective: To review teaching and mentoring techniques of experienced skull base surgeons and educators Study Design: Expert commentary. Setting: 8th Quadrennial International Conference on vestibular schwannoma and other CPA tumors, panel on teaching, and mentoring. Main Outcome Measures: Experiences and opinions of experienced skull base surgeons, both neurosurgeons and neurotologists, presented and discussed at the conference. Conclusions: Obtaining surgical mastery is essential for the teachers of skull base surgery. Hard work and practice with immediate and constant feedback on performance is an essential component to success. Creating a patient-centered culture that encourages academic achievement is an accelerator for success of a training program. Both the mentor and the mentee must play an intentional and active role to maximize learning.

Objective: Posterior external auditory canal (EAC) hypesthesia (Hitselberger's sign) has been previously described to occur in all vestibular schwannomas (1966) but has not been studied since. We hypothesized that sensory loss may be related to tumor size and sought to determine if this clinical sign could predict preoperative characteristics of vestibular schwannomas, intraoperative findings, and/or surgical outcomes. Study Design: Prospective observational study. Setting: Tertiary referral center. Patients: Twenty-five consecutive patients who underwent surgery for vestibular schwannoma. Intervention: Patients were tested for the presence of EAC hypesthesia or anesthesia. Main Outcome Measures: Preoperative, intraoperative, and postoperative findings were recorded, including facial nerve function, hearing function, tumor size, tumor nerve of origin, and extent of resection. Results: Twelve patients (48%) demonstrated either posterior EAC hypesthesia (11 patients) or anesthesia (1 patient). Sensory loss was a significant predictor of size (tumor maximal diameter) (p = 0.004). Median tumor diameter was 1.7 cm in the cohort with intact sensation versus 2.9 cm in the cohort with sensory loss. Patients with sensory loss were also significantly more likely to be associated with a superior vestibular nerve origin tumor (p = 0.01). Preoperative sensory loss did not significantly predict postoperative facial outcome (p = 0.10). Conclusion: Neurological exam findings may be overlooked in the workup of brain tumors. Posterior EAC hypesthesia is a predictor of tumor size and superior vestibular nerve origin. These findings may have implications for patient selection, particularly with the middle cranial fossa approach. Furthermore, given this relationship with tumor size, this clinical biomarker should be studied as a potential predictor of tumor growth.

It is with a sad heart that I write this obituary of my dear friend, Dr. Fred Owens. Fred was born in Hazard, Kentucky on May 26, 1933. He graduated from Georgetown College and then received his Doctor of Medicine from the University of Louisville. After a brief time as a rural general practitioner, he completed his Otolaryngology Head and Neck Surgery Residency at the University of West Virginia. Following Fellowship at the House Clinic, he entered the private practice of Otology and Neurotology in Dallas, Texas in 1971. Later joined by his son, Dr. Robert Owens, he spent his entire career in Dallas. Fred was a unique private practice physician. In many respects, he was also an academician. He founded the Dallas Foundation of Otology and established a temporal bone laboratory. He conducted temporal bone courses free of charge for residents and practitioners from the United States and Mexico. He was a guest professor and lecturer at forums in the United States, Europe, Canada, Mexico, South America, and Asia. He was very active in the American Academy of Otolaryngology–Head and Neck Surgery. He served as the Chair of the Finance and Investment committee from 2000 to 2005 and was the Secretary Treasurer of the Board of Directors from 1999 through 2005. He was awarded the Board of Governors Practitioner Excellent award in 2014 and received a Presidential Citation in 2014. He also presented instruction courses and served on various academy committees. He was very active in the Triological Society and was the Immediate Past President at the time of his death on November 4, 2016. Fred founded the Hearing School of the Southwest, the only school of its type in the Dallas, Fort Worth Metroplex. The non-profit school provides early childhood education for cochlear implant children. Fred is survived by his wife, Patty, seven children, 15 grandchildren, and two great-grandchildren. Fred had many other interests including fly fishing, bird hunting, ranching, and raising cattle. I knew Fred very well professionally but it was through the outside activities of hunting and fishing that I knew him on a very deep personal level. Fred was the kindest, most considerate person that I have ever known. He was always available to support others in their time of need. His greatest pleasure was to take other people hunting on his ranch. For more than 30 years, Gary Jackson, Bill Williams, Fred, and I went hunting and fishing. The fond memories are innumerable. One of Fred's favorite activities was to attend Cowboy Sunday School near his ranch in North Texas. We would kid him that he was studying for the final examination. I have no doubt that he passed without difficulty. In fact, I am sure that he graduated summa cum laude. We will miss Fred greatly. His kind and gentle manner and infectious smile will be missed by all. I will miss you my dear friend!

OBJECTIVE To evaluate whether an auditory brainstem implant (ABI) can impact levels of tinnitus in neurofibromatosis type-2 (NF2) patients who have undergone translabyrinthine craniotomy for vestibular schwannoma (VS) removal and to evaluate the burden of tinnitus in these patients. STUDY DESIGN A retrospective case series and patient survey. SETTING Tertiary neurotologic referral center. PATIENTS NF2 patients who underwent translabyrinthine removal of VS and ABI placement between 1994 and 2015. INTERVENTIONS A survey, retrospective review and two validated tinnitus handicap questionnaires (tinnitus handicap inventory [THI] and tinnitus visual analogue scale [VAS]) were used to characterize the degree of tinnitus in NF2 patients and whether an ABI can alter tinnitus levels. MAIN OUTCOME MEASURES(S) Survey results, THI and VAS scores. RESULTS One hundred twelve ABI users were contacted and 43 patients (38.3)% responded to our survey. Tinnitus was reported in 83.7% of patients. The THI score for responders was 17.8 ± 20.5 standard deviation (SD). For survey participants, the ABI reduced tinnitus levels (mean VAS: Off = 3.5; On 1-h = 2.1; p = 0.048). For patients who subjectively reported that the ABI reduced tinnitus loudness, tinnitus levels were immediately reduced on ABI activation and after 1 hour of use (mean VAS: Off = 4.8; On = 2.4; On 1-h = 1.8; p < 0.01). Suppression did not continue after the device was turned off. Audiological performance with the ABI did not correlate with tinnitus suppression. CONCLUSION NF2 patients who have undergone removal of VS have a significant tinnitus handicap and benefit from tinnitus suppression through utilization of an ABI possibly through masking or electrical stimulation of the auditory brainstem.

Little is known about the reasons for occurrence of facial nerve palsy after removal of cerebellopontine angle tumors. Since the intra-arachnoidal portion of the facial nerve is considered to be so vulnerable that even the slightest tension or pinch may result in ruptured axons, we tested whether a graded stretch or controlled crush would affect the postoperative motor performance of the facial (vibrissal) muscle in rats. Thirty Wistar rats, divided into five groups (one with intact controls and four with facial nerve lesions), were used. Under inhalation anesthesia, the occipital squama was opened, the cerebellum gently retracted to the left, and the intra-arachnoidal segment of the right facial nerve exposed. A mechanical displacement of the brainstem with 1 or 3 mm toward the midline or an electromagnet-controlled crush of the facial nerve with a tweezers at a closure velocity of 50 and 100 mm/s was applied. On the next day, whisking motor performance was determined by video-based motion analysis. Even the larger (with 3 mm) mechanical displacement of the brainstem had no harmful effect: The amplitude of the vibrissal whisks was in the normal range of 50°–60°. On the other hand, even the light nerve crush (50 mm/s) injured the facial nerve and resulted in paralyzed vibrissal muscles (amplitude of 10°–15°). We conclude that, contrary to the generally acknowledged assumptions, it is the nerve crush but not the displacement-induced stretching of the intra-arachnoidal facial trunk that promotes facial palsy after cerebellopontine angle surgery in rats.