Gompel, Jamie J. Van

Objective To compare cochlear implant (CI) and auditory brainstem implant (ABI) performance in patients with NF2-related schwannomatosis (NF2) Study Design Historical cohort. Setting Tertiary academic center. Patients A total of 58 devices among 48 patients were studied, including 27 ABIs implanted from 1997 to 2022 and 31 CIs implanted from 2003 to 2022. Three patients had bilateral ABIs, three had bilateral CIs, three had an ABI on one side and a CI on the other, one had a CI that was later replaced with an ipsilateral ABI, and one had an ABI and CI concurrently on the same side. Interventions CI or ABI ipsilateral to vestibular schwannoma. Main Outcome Measures Open-set speech perception, consonant-nucleus-consonant word scores, and AzBio sentence in quiet scores. Results Among all patients, 27 (47%) achieved open-set speech perception, with 35 (61%) daily users at a median of 24 months (interquartile range [IQR], 12–87 mo) after implantation. Comparing outcomes, CIs significantly outperformed ABIs; 24 (77%) CIs achieved open-set speech perception compared with 3 (12%) ABIs, with median consonant-nucleus-consonant and AzBio scores of 31% (IQR, 0–52%) and 57% (IQR, 5–83%), respectively, for CIs, compared with 0% (IQR, 0–0%) and 0% (IQR, 0–0%), respectively, for ABIs. Patients with ABIs were younger at diagnosis and at implantation, had larger tumors, and were more likely to have postoperative facial paresis. Conclusion Many patients with NF2-associated vestibular schwannoma achieved auditory benefit with either a CI or an ABI; however, outcomes were significantly better in those patients who were able to receive a CI. When disease and anatomy permit, hearing rehabilitation with a CI should be considered over an ABI in these patients. Tumor management strategies that increase the ability to successfully use CIs should be strongly considered given the high risk of losing bilateral functional acoustic hearing in this population.

Objective The objective of the current study was to present the results of an international working group survey identifying perceived limitations of existing facial nerve grading scales to inform the development of a novel grading scale for assessing early postoperative facial paralysis that incorporates regional scoring and is anchored in recovery prognosis and risk of associated complications. Study Design Survey. Setting A working group of 48 multidisciplinary clinicians with expertise in skull base, cerebellopontine angle, temporal bone, or parotid gland surgery. Results House-Brackmann grade is the most widely used system to assess facial nerve function among working group members (81%), although more than half (54%) agreed that the system they currently use does not adequately estimate the risk of associated complications, such as corneal injury, and confidence in interrater and intrarater reliability is generally low. Simplicity was ranked as the most important attribute of a novel postoperative facial nerve grading system to increase the likelihood of adoption, followed by reliability and accuracy. There was widespread consensus (91%) that the eye is the most critical facial region to focus on in the early postoperative setting. Conclusions Members were invited to submit proposed grading systems in alignment with the objectives of the working group for subsequent validation. From these data, we plan to develop a simple, clinically anchored, and reproducible staging system with regional scoring for assessing early postoperative facial nerve function after surgery of the skull base, cerebellopontine angle, temporal bone, or parotid gland.

BACKGROUND AND OBJECTIVES: Schwannomas originating from the lower cranial nerves (LCNS) are rare and pose a significant surgical challenge. Resection is the mainstay treatment; however, risk of treatment morbidity is considerable, and the available literature regarding differential treatment outcomes in this vulnerable population is sparse. METHODS: A single-institution cohort study and systematic literature review of LCNS were performed. RESULTS: Fifty-eight patients were included: 34 underwent surgical resection and 24 underwent stereotactic radiosurgery (SRS). The median age at diagnosis was 48 years (range 17-74). Presenting symptoms were dysphagia (63%), dysarthria/hypophonia (47%), imbalance (33%), and hearing loss/tinnitus (30%). Tumor size was associated with surgical resection, as compared with initial SRS (4.1 cm vs 1.5 cm, P = .0001). Gross total resection was obtained in 52%, with tumor remnants predominantly localized to the jugular foramen (62%). Post-treatment worsening of symptoms occurred in 68% of surgical and 29% of SRS patients ( P = .003). Postoperative symptoms were mostly commonly hypophonia/hoarseness (63%) and dysphagia (59%). Seven patients (29%) had new neurological issues after SRS treatment, but symptoms were overall milder. The median follow-up was 60 months (range 12-252); 98% demonstrated meaningful clinical improvement. Eighteen surgical patients (53%) underwent adjuvant radiation at a median of 5 months after resection (range 2-32). At follow-up, tumor control was 97% in the surgical cohort and 96% among SRS patients. CONCLUSION: Although LCNS resection is potentially morbid, most postoperative deficits are transient, and patients achieve excellent tumor control—particularly when paired with adjuvant SRS. For minimally symptomatic patients undergoing surgical intervention, we advise maximally safe resection with intracapsular dissection to preserve nerve integrity where possible. For residual or as a primary treatment modality, SRS is associated with low morbidity and high rates of long-term tumor control.

OBJECTIVE The objective of this study was to clarify the detailed clinical course of recurrent clival chordoma and the outcomes of each treatment modality. METHODS A single-center retrospective analysis was conducted on patients seen for recurrent clival chordoma. The cohort was identified from those who underwent surgery, stereotactic radiosurgery, or proton therapy at the authors’ institution between 1990 and 2022. RESULTS A total of 95 recurrences in 40 patients with a median (interquartile range [IQR]) follow-up of 43 (18–79) months were identified. The median (IQR) age at the time of diagnosis was 48 (36–62) years, and 55% of patients were male. Twenty-three patients were treated with surgery followed by adjuvant radiation before the first recurrence. The median (range) number of recurrences per patient was 2 (1–8), and the median (IQR) time to the first recurrence was 29 (9–51) months. The recurrences were treated with one or more of the following therapies: surgery, radiation, systemic therapy, and laser interstitial thermal therapy (LITT). Surgery was performed for 44 recurrences in 25 patients. Radiation was used to treat 42 recurrences in 28 patients. Patients with recurrences treated with surgery plus radiation had the longest progression-free survival (PFS) (median [95% CI] overall survival [OS] 120 [0–245] months, p < 0.01, log-rank test). Patients with recurrences but without prior radiation had longer PFS than those patients with prior radiation. The median (95% CI) OS after the first recurrence was 68 (54–82) months, 5-year OS after the first recurrence was 48%, and 10-year OS was 27%. Multivariate Cox regression analysis showed that mortality after the first recurrence was significantly associated with no adjuvant radiation (HR 0.149, 95% CI 0.038–0.59, p = 0.0067), older age at the time of the first recurrence (HR 1.04, 95% CI 1.01–1.08, p = 0.021), and total number of recurrences (p = 0.032). Seven patients received systemic therapy, and the median (95% CI) OS of these patients since initiation of systemic therapy was 31 (11–51) months. Imatinib and/or nivolumab were used in 6 patients (15%). One patient (3%) was treated with LITT for his fourth recurrence. CONCLUSIONS Despite the aggressive nature of recurrent chordoma, 14 of 29 patients (48%) survived for more than 5 years after the initial recurrence using combined therapies. Multiple treatment options may contribute to the long-term survival of patients with this intractable tumor.

OBJECTIVE Antifibrinolytics, such as tranexamic acid (TXA), have been shown to decrease intraoperative blood loss across multiple surgical disciplines. However, they carry the theoretical risk of thromboembolic events secondary to induced hypercoagulability. Therefore, the aim of this study was to systematically review the available literature and perform a meta-analysis on the use of TXA in meningioma resection to assess thromboembolic risks. METHODS The PubMed, Web of Science, and Google Scholar databases were reviewed for all randomized controlled trials presenting primary data on TXA use during resection of intracranial meningiomas. Data were gathered on operative duration, venous thromboembolic complications, deep venous thrombosis, use of allogeneic blood transfusion, estimated blood loss (EBL), and postoperative hemoglobin. Patients who received TXA were compared with controls who did not receive TXA intraoperatively using random-effects models. RESULTS A total of 508 unique articles were identified, of which 493 underwent full-text review. Ultimately, 6 studies with 381 total patients (190 receiving TXA) were included in the final analysis. All 6 trials were randomized, blinded, and placebo controlled with a TXA administration rate of a 20-mg/kg load followed by a 1-mg/kg/hr infusion. All studies were performed in lower-middle-income countries. There were no reported instances of venous thromboembolism (VTE) in the TXA and non-TXA cohorts. Patients receiving TXA exhibited fewer allogeneic transfusions (21.5% vs 41.6% [OR 0.26, 95% CI 0.09–0.77], p = 0.02) and lower EBL (MD −282.48 mL [95% CI −367.77 to −197.20 mL], p < 0.001) compared with patients who did not receive TXA, and they also had lower rates of perioperative complications (10.7% vs 19.9% [OR 0.47, 95% CI 0.2–0.95], p = 0.04). CONCLUSIONS Current literature suggests that TXA is not associated with increased risk for VTE when administered during resection of intracranial meningioma. TXA appears to decrease intraoperative blood loss and allogeneic transfusion requirements during meningioma resection and thus may improve the safety of surgical management of this pathology.

Abstract Disclosure: D.Z. Erickson: None. D. Donegan: None. J. Van Gompel: None. J. Atkinson: None. M. Link: None. F. Meyer: None. M. Peris-Celda: None. G. Spears: None. J. Bornhorst: None. M. Hoplin: None. Dysnatremias are common after neurosurgical procedures. Depending on the cohort assessed, transient arginine vasopressin deficiency (AVD) following neurological procedures is seen in up to 46% of patients which can delay discharge. Copeptin (COPEP), a stable surrogate marker of arginine vasopressin, has demonstrated utility in the prediction of postoperative AVD, however COPEP cutoff and sample timing has varied. Aim: To assess the optimal sampling time and cut point concentration of COPEP to predict the development of post-surgical AVD. Method: Adults who had transsphenoidal surgery (TSS) for a sellar or suprasellar mass between February 2020 and April 2022 without pre-existing AVD were prospectively enrolled if agreeable. Two COPEP samples (immunofluorescent assay on B.R.A.H.M.S Kryptor Compact PLUS) included “early” sample 1-6 hours following extubation, and another post-op day 1 (POD1, 10-30 hours of extubation). Patients were assessed for the development of AVD; defined as new onset hypotonic (&lt; 295 mmol/kg) polyuria (&gt;50 ml/kg/d) without other causes. Patient demographics and tumor characteristics were collected. Results: 192 patients (median age 54.5 (39.8-67.0) years with 54.2% female) were included. Surgical indications included non-functioning pituitary adenoma (N=101), functioning pituitary adenoma (N= 78), disorders or the craniopharyngeal duct (N=10) and other (N=3). Median COPEP levels were associated with age, but not sex. Median COPEP levels were significantly lower at both time points in patients who developed AVD (N=20, 10.4%) vs those who did not, (early: 4.9 vs 18.7 pmol/L, P= &lt;0.001; POD1: 3.35 vs 4.9 pmol/L, P=&lt;0.001). Change in median COPEP level between the 2 sample times was lower in those who developed AVD -1.8 pmol/L vs who did not -12.6 pmol/L (P&lt;0.001). ROC curve analysis of early COPEP indicated that a level &gt;20.3 pmol/L had a negative predictive value (NPV) of 97% whereas POD1 level &gt;6.7 pmolL had a NPV of 96%. In univariate logistic analysis, lower early COPEP was associated with higher risk of AVD (OR=0.34, CI 0.26 -0.62, p=0.008), with an optimal cut point of 8.5 pmol/L. A similar association was seen for POD1 COPEP (OR=0.19, CI 0.07- 0.53, p= 0.002), which had an optimal cut point of 4.3 pmol/L. In patients with disorders of the craniopharyngeal system vs those who had TSS for other reasons, AVD was more common (60% vs 9%, P&lt;0.001) and median COPEP levels were lower at both time points. Those without AVD who received stress dose steroids intraoperatively had lower median early COPEP (11.7 vs 19.1 pmol/L, P=0.27). Conclusion: In early samples taken following extubation, the optimal COPEP cut point for AVD diagnosis was 8.5 pmol/L and a level of &gt;20.3 pmol/L has predicative utility in excluding AVD. However, caution should be used in patients who are administered glucocorticoids intra-operatively as this was associated with a lower median COPEP level. Presentation: Thursday, June 15, 2023

Purpose: Temporal encephaloceles are a cause of drug-resistant temporal lobe epilepsy; however, their relationship with epileptogenesis is unclear, and optimal surgical resection is uncertain. EEG source localization (ESL) may guide surgical decision-making. Methods: We reviewed patients at Mayo Clinic Rochester with drug-resistant temporal lobe epilepsy and temporal encephaloceles, who underwent limited resection and had 1-year outcomes. EEG source localization was performed using standard density scalp EEG of ictal and interictal activity. Distance from dipole and standardized low-resolution brain electromagnetic tomography (sLORETA) solutions to the encephalocele were measured. Concordance of ESL with encephalocele and surgical resection was compared with 1-year surgical outcomes. Results: Seventeen patients met criteria. The mean distances from ESL results to encephalocele center for dipole and sLORETA analyses were 23 mm (SD 9) and 22 mm (SD 11), respectively. Ten patients (55.6%) had Engel I outcomes at 1 year. Dipole-encephalocele distance and sLORETA-encephalocele distance were significantly longer in patients with Engel I outcome and patients whose encephalocele was contained by sLORETA had worse outcome as well; however, multiple logistic regression analysis found that only containment of encephalocele by the sLORETA current density was significant (P < 0.05), odds ratio 0.12 (95% confidence interval [0.021, 0.71]). Conclusions: EEG source localization of scalp EEG localizes near encephaloceles, however, typically not in the encephalocele itself; this may be due to scalp EEG sampling propagated activity or alternatively that the seizure onset zone extends beyond the herniated cortex. Surprisingly, we observed increased ESL to encephalocele distances in patients with excellent surgical outcomes. Larger cohort studies including intracranial EEG data are needed to further explore this finding.

Abstract Introduction The American Association of Neurological Surgeons (AANS), North American Skull Base Society (NASBS), American Rhinologic Society (ARS), and American Neurotology Society (ANS) fellowship directories are important information repositories for skull base surgical fellowship programs. However, there is limited research on the amount and depth of information available through these resources. The objective of the present study is to assess Web site accessibility and information availability for individual fellowship programs listed within the AANS, NASBS, ARS, and ANS fellowship directories. Methods Lists of all accredited skull base surgical programs were obtained from the AANS and NASBS fellowship directories. Duplications in listed programs were removed, and systematic queries via an online search engine were conducted to identify fellowship Web sites. From each available Web site, information pertaining to 24 different variables was collected and organized into two categories—recruitment and education. Differences in the availability of information on recruitment and education were then compared across Web sites and contextualized relative to other surgical specialties. Results After excluding duplicates, 113 fellowship programs were identified, of which 99 (87.6%) had accessible Web sites. Of the 48 listed by the NASBS, direct Web site links were available for 33 (68.8%), email contacts were accessible for 32 (66.7%), and phone numbers were listed for 6 (12.5%). Of the 39 programs listed by the AANS, none included Web site links, 38 (97.4%) provided an email contact, and 39 (100%) listed a departmental contact telephone number. All 28 (100%) programs listed by the ANS provided a phone and email contact in addition to a Web site link to each institutional Web site. Of the 33 programs listed by the ARS, 29 (88%) had a departmental contact telephone number, 31 (94%) had an email contact available, and 4 (12%) had a program Web site link directly available from the database Web site. Of the 99 total programs, fellowship Web sites displayed an average of 5.46 (42.0%) of the 13 recruitment features and 4.80 (42.6%) of the 11 education features. Programs in the geographic Northeast were significantly less likely to present information pertaining to recruitment (p = 0.023). Furthermore, programs in geographic Northeast and West were significantly less likely to present information focused on surgical training and/or education (p = 0.006). Conclusion Although many skull base fellowship programs have maintained comprehensive program Web sites, certain critical aspects remain deficient, and some programs provide little to no information. Providing more detailed information about programs can prove mutually beneficial for fellowship program directors and candidates.

Abstract Background Neurofibromatosis type 2 (NF2)-related schwannomatosis is an autosomal dominant tumor-predisposition syndrome characterized by bilateral vestibular schwannomas (VS). In patients with VS associated with NF2, vascular endothelial growth factor A inhibitor, bevacizumab, is a systemic treatment option. The aim of this study is to retrospectively evaluate NF2 patient responses to bevacizumab on VS growth and symptom progression. Methods This is a retrospective analysis of patients seen at the Mayo Clinic Rochester Multidisciplinary NF2 Clinic. Results Out of 76 patients with NF2 evaluated between 2020 and 2022, we identified 19 that received treatment with bevacizumab. Thirteen of these patients discontinued bevacizumab after median treatment duration of 12.2 months. The remaining 6 patients are currently receiving bevacizumab treatment for a median duration of 9.4 months as of March, 2023. Fifteen patients had evaluable brain MRI data, which demonstrated partial responses in 5 patients, stable disease in 8, and progression in 2. Within 6 months of bevacizumab discontinuation, 5 patients had rebound growth of their VS greater than 20% from their previous tumor volume, while 3 did not. Three patients with rebound growth went on to have surgery or irradiation for VS management. Conclusions Our single-institution experience confirms prior studies that bevacizumab can control progression of VS and symptoms associated with VS growth. However, we note that there is the potential for rapid VS growth following bevacizumab discontinuation, for which we propose heightened surveillance imaging and symptom monitoring for at least 6 months upon stopping anti-VEGF therapy.