Auditory brainstem implantation: surgical experience and audiometric outcomes in the pediatric population

OBJECTIVE

Pediatric data regarding treatment via an auditory brainstem implant (ABI) remains sparse. The authors aimed to describe their experience at their institution and to delineate associated demographic data, audiometric outcomes, and surgical parameters.

METHODS

An IRB-approved, retrospective chart review was conducted among the authors' pediatric patients who had undergone auditory brainstem implantation between 2012 and 2021. Demographic information including sex, age, race, coexisting syndrome(s), history of cochlear implant placement, average duration of implant use, and follow-up outcomes were collected. Surgical parameters collected included approach, intraoperative findings, number of electrodes activated, and complications.

RESULTS

A total of 19 pediatric patients had an ABI placed at the authors' institution, with a mean age at surgery of 4.7 years (range 1.5-17.8 years). A total of 17 patients (89.5%) had bilateral cochlear nerve aplasia/dysplasia, 1 (5.3%) had unilateral cochlear nerve aplasia/dysplasia, and 1 (5.3%) had a hypoplastic cochlea with ossification. A total of 11 patients (57.9%) had a history of cochlear implants that were ineffective and required removal. The mean length of implant use was 5.31 years (0.25-10 years). Two patients (10.5%) experienced CSF-related complications requiring further surgical intervention. The most recent audiometric outcomes demonstrated that 15 patients (78.9%) showed improvement in their hearing ability: 5 with sound/speech awareness, 5 able to discriminate among speech and environmental sounds, and 5 able to understand common phrases/conversation without lip reading. Nine patients (47.4%) are in a school for the deaf and 7 (36.8%) are in a mainstream school with support.

CONCLUSIONS

The authors' surgical experience with a multidisciplinary team demonstrates that the retrosigmoid approach for ABI placement in children with inner ear pathologies and severe sensorineural hearing loss is a safe and effective treatment modality. Audiometric outcome data showed that nearly 79% of these patients had an improvement in their environmental and speech awareness. Further multicenter collaborations are necessary to improve these outcomes and potentially standardize/enhance electrode placement.

NIMG-14. RADIOLOGIC ASSESSMENT OF BRAIN METASTASES UNDERGOING LASER INTERSTITIAL THERMAL THERAPY (LITT)

BACKGROUND

Laser Interstitial Thermal Therapy (LITT) is a novel treatment for brain metastases (BMs), and data regarding radiologic changes and long-term efficacy is sparse. This study explored volumetric changes in responding and non-responding BMs and their associations with lesion-specific progression-free survival (PFS-L).

METHODS

Patients with BMs treated with LITT were retrospectively enrolled. 3D volumes-of-interest of the contrast-enhancing BM tissue (CE) on pre-, post-LITT, and follow-up MRI scans were obtained. BMs were followed until progression or censoring. PFS-L was determined using the modified RANO criteria to assess treatment efficacy on each lesion.

RESULTS

Thirty-one BMs (from 30 patients) were preliminarily analyzed. 2 BMs had no follow-up scans. Median follow-up for 29 BMs was 248 days (range 28-2200). Median time to response was 430 days (responders n=7/29), median time to progression was 176 days (progressive disease n=7/29). Pre-LITT CE volume was a predictor of PFS-L (p=0.001), with BMs> 2.5 cc being 14 times more likely to undergo progression. Differences in age and primary tumor site did not impact PFS-L, whereas PFS-L tended to be longer in females (p=0.059), and in frontal and deep grey matter BMs (p=0.11). Post-LITT CE volume was higher than pre-LITT (p< 0.0001, median increase 59%), with no significant differences among responders, stable disease, and progressive disease. In each responding BM, the CE volume shrinkage over time was described by an exponential decay (R2 ranging 0.92-1.0 and half-life ranging 16.55-204 days). All responding BMs showed a pooled exponential decay with R2=0.88 and half-life=75.6 days.

CONCLUSIONS

Our data suggest that smaller BMs may have improved outcomes from LITT treatment. CE volumes may increase in the early post-procedural scans, possibly due to both inflammatory changes and thermal damage. The characterization of the volumetric changes across time for responding lesions may be useful for an early detection of BMs at risk for progression.

Postoperative Outcomes of Patients with Thin Bone Overlying the Superior Semicircular Canal: A Single Institution's Experience

BACKGROUND

Superior semicircular canal dehiscence (SSCD) is defined by a bony defect overlying the superior semicircular canal (SSC) in the middle cranial fossa floor, causing a myriad of vestibular and auditory symptoms. Patients with thin bone without full dehiscence overlying the SSC also present with similar symptoms. There are currently no guidelines for surgical management of patients with thin bone. The authors offer their experience with thin bone patients to characterize their symptomatology and explore whether these patients benefit from surgical intervention typically offered to SSCD patients.

METHODS

Two hundred fifty-six patients evaluated for SSCD from 2011 to 2019 were reviewed. High-resolution coronal computed tomography scans with 0.6-mm slice thickness of the temporal bones were assessed to determine whether the patient had a true dehiscence or a thin bone covering overlying the SSC. Bone that was ≤0.5 mm was considered to be "thin bone." Parameters of interest included patient demographics as well as preoperative and postoperative symptomatology. A P value < 0.05 was considered statistically significant.

RESULTS

Forty-eight patients met inclusion criteria of having "thin bone." The mean age was 48.13 ± 12.03 years, and 65.5% of patients were female. Of the preoperative symptoms evaluated, the greatest postoperative symptomatic resolution was noted in hearing loss (92.3%), vertigo (94.4%), and oscillopsia (100%). Dizziness (56.5%) had the lowest symptomatic resolution rate.

CONCLUSIONS

Surgical management of thin bone patients via middle fossa craniotomy, a similar technique to SSCD repair, provides significant symptomatic resolution. Therefore, surgery should be considered in thin bone patients with debilitating symptoms, albeit not having a true dehiscence.

Neurosurgical Management of Interspinous Device Complications: A Case Series

Background

Best practice guidelines for treating lumbar stenosis include a multidisciplinary approach, ranging from conservative management with physical therapy, medication, and epidural steroid injections to surgical decompression with or without instrumentation. Marketed as an outpatient alternative to a traditional lumbar decompression, interspinous process devices (IPDs) have gained popularity as a minimally invasive stabilization procedure. IPDs have been embraced by non-surgical providers, including physiatrists and anesthesia interventional pain specialists. In the interest of patient safety, it is imperative to formally profile its safety and identify its role in the treatment paradigm for lumbar stenosis.

Case Description

We carried out a retrospective review at our institution of neurosurgical consultations for patients with hardware complications following the interspinous device placement procedure. Eight cases within a 3-year period were identified, and patient characteristics and management are illustrated. The series describes the migration of hardware, spinous process fracture, and worsening post-procedural back pain.

Conclusions

IPD placement carries procedural risk and requires a careful pre-operative evaluation of patient imaging and surgical candidacy. We recommend neurosurgical consultation and supervision for higher-risk IPD cases.

Bilateral Superior Semicircular Canal Dehiscence Concurrent With Ehlers-Danlos Syndrome: A Case Report

Superior semicircular canal dehiscence (SSCD) is characterized by temporal bone thinning, which creates an opening between the inner ear and middle cranial fossa. Ehlers-Danlos syndrome, hypermobility type (EDS-HT) is a genetic collagen synthesis disorder, often resulting in bony abnormalities. We present the case of a 39-year-old female with EDS-HT who exhibited the otological symptoms characteristic of bilateral SSCD. High-resolution computed tomography (CT) scans confirmed the diagnosis. The patient elected for middle fossa craniotomy and noted symptomatic improvement. Due to its potential to confer bone fragility, EDS-HT may predispose SSCD development. Further examination of the relationship between these disorders is necessary.

Superior Semicircular Canal Dehiscence Outcomes in a Consecutive Series of 229 Surgical Repairs With Middle Cranial Fossa Craniotomy

BACKGROUND

Superior semicircular canal dehiscence (SSCD) is the appearance of a third mobile window between the middle fossa and the superior semicircular canal. Surgical management is indicated in patients with persistent and debilitating symptoms. The purpose of this study was to evaluate the association between preoperative variables that may impact postoperative symptomatic resolution.

METHODS

A single-institution retrospective analysis was performed on patients who were surgically treated for SSCD. Patients were divided to different cohorts based on unilateral or bilateral nature of the disease. A P value <0.05 was considered statistically significant.

RESULTS

A total of 229 surgical repairs were analyzed. Mean age was 51 years (± 7.8 years), and 55.9% of patients were female. All cohorts were similar with respect to baseline demographics. The most commonly reported preoperative symptoms were tinnitus, dizziness, and autophony. The greatest symptomatic resolution was seen in autophony, internal sound amplification, hyperacusis, and oscillopsia. The unilateral SSCD cohort had significantly higher improvement of autophony (P = 0.003), aural fullness (P = 0.05), tinnitus (P = 0.006), hearing loss (P = 0.02), dizziness (P = 0.006), and headache (P = 0.007), compared with the bilateral SSCD cohorts. Among patients with bilateral disease, those with unilateral surgery reported greater symptomatic resolution with respect to hyperacusis (P = 0.03), hearing loss (P = 0.02), dizziness (P = 0.03), and disequilibrium (P < 0.001), than those with bilateral operations.

CONCLUSIONS

Surgical management of SSCD leads to high rates of postoperative symptomatic improvement. Patients with unilateral SSCD benefit greater symptomatic resolution compared to those with bilateral pathology.

Adjuvant radiotherapy for atypical meningiomas is associated with improved progression free survival

PURPOSE

To assess the progression-free survival benefits of adjuvant radiotherapy (ART) following surgical resection compared to surgery alone in high-grade meningioma patients.

METHODS

We retrospectively identified 43 patients with atypical meningiomas, who underwent either radiotherapy post-surgical resection (Surgery+ART) or surgery alone (Surgery alone) at our institution between February 2007 to March 2019. GTR was achieved in 28 patients, and STR, in 11. Patient, meningioma, and treatment data were extracted from records and compared using Kaplan-Meier methodology, log-rank tests, and Cox proportional hazard models. Radiation complications were also evaluated.

RESULTS

Overall 32.6% (n = 14) of patients, 6 patients in the Surgery+ART group and 8 in the Surgery alone group, experienced recurrence. In the Surgery+ART group, the median PFS time was 46.5 months (CI: [35.8-50.6]), compared to 24.5 months (CI: [18.3-32.9]) in the Surgery alone group. 2-year PFS for Surgery+ART was 100% vs. 69.0% for Surgery alone, and the 5-year PFS rate was 70.6% and 39.2%, respectively (log-rank p-value = .004).

CONCLUSIONS

Our data revealed a significant PFS increase for those treated with adjuvant radiotherapy following surgery compared to surgery alone. Future prospective studies evaluating differing radiation modalities and dosages should be conducted.

A systematic review of stereotactic radiofrequency ablation for hypothalamic hamartomas

BACKGROUND

The seizure activity associated with hypothalamic hamartomas (HHs) is refractory to medical management and surgical intervention is often required. Stereotactic Radiofrequency Ablation (SRFA) is a minimally invasive technique offering targeted lesion ablation with a reduced risk of complications.

OBJECTIVE

Here, we review the current literature on the use of SRFA for HHs.

METHODS

This study was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for systematic literature review. A database search of PubMed, Cochrane, Embase, and Web of Science was conducted in July 2020.

RESULTS

A total of 12 articles were included in this review, showing outcomes for 185 unique patients. Of these patients, 142 (76.8%) experienced some extent of therapeutic benefit in alleviating seizures following SRFA, with 128 (69.2%) patients achieving complete freedom from seizures. Common transient complications included hyponatremia (52 patients, 28.1%), hyperphagia (48 patients, 25.9%), hyperthermia (47 patients, 25.4%), Horner's syndrome (103 patients, 55.7%), and weight gain (75 patients, 40.5%).

CONCLUSIONS

SRFA is a potential therapy for patients with HHs, especially when resection confers significant risk to surrounding structures. Multiple rounds of SRFA treatment may be needed in approximately a quarter of patients to improve gelastic seizure outcomes but may not affect non-gelastic seizures. There is limited data on the use of SRFA for HHs and further case series and clinical trials are needed to establish the use of SRFA for HHs.

Meta-analysis of adjuvant radiotherapy for intracranial atypical and malignant meningiomas

INTRODUCTION

Meningiomas comprise 33% of all CNS tumors. The World Health Organization (WHO) describes meningiomas as benign (BM), atypical (AM), and malignant/anaplastic (MM). High-grade meningiomas such as AMs and MMs are more aggressive, recur more frequently, and portend a worse prognosis than BMs. Currently, the standard treatment for high-grade meningiomas, especially AMs, is ill-defined. In particular, the benefit to survival outcomes of adjuvant radiotherapy post-surgical resection remains unclear. In this study, we investigated the effect of adjuvant radiotherapy (ART) post-surgery on survival outcomes compared to surgery alone for high-grade meningiomas.

METHODS

PRISMA guidelines were a foundation for our literature review. We screened the PubMed database for studies reporting overall survival (OS), progression free survival (PFS), and tumor recurrence for intracranial, primary AM and MMs treated with surgery+ART or surgery alone. Fixed and random effect models compared tumor control rate for AM aforementioned groups.

RESULTS

Mean 5-year PFS was 76.9% for AM (surgery+ART) and 55.9% for AM (surgery alone) patients. Mean 5-year OS was 81.3% and 74% for AM (surgery+ART) and AM (surgery alone) groups, respectively. Overall, the mean 5-year PFS for aggregated high-grade meningiomas AM+MM (surgery+ART) was 67.6%. Fixed effect models revealed tumor control rate as 76% for AM (surgery+ART) and 69% for AM (surgery alone) groups. ART induced toxicity incidence ranged from 12.0% to 35.5% for AM and MM patients.

CONCLUSIONS

Our analysis suggests that (surgery+ART) may increase PFS, OS, and tumor control rates in high-grade meningiomas. However, further studies involving surgery+ ART should be conducted to fully evaluate the ideal radiosurgical candidate, modality, and dosage.

RADT-33. RADIOSURGERY VERSUS COMBINATION RADIOSURGERY-BEVACIZUMAB FOR THE TREATMENT OF RECURRENT HIGH-GRADE GLIOMA: A SYSTEMATIC REVIEW

BACKGROUND

High-grade gliomas (HGG) comprise the most common primary adult brain cancers and universally recur. Combination re-radiation therapy (reRT) and bevacizumab (BVZ) therapy for recurrent HGG is common, but its reported efficacy is mixed.

OBJECTIVE

To assess clinical outcomes after reRT±BVZ in recurrent HGG patients receiving stereotactic radiosurgery (SRS), hypo-fractionated (HFSRT), or fully fractionated RT (FSRT).

METHODS

We performed a systematic review of PubMed, Web of Science, Scopus, Embase, and Cochrane databases, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We identified studies reporting outcomes for patients with recurrent HGG treated via reRT±BVZ. Cohorts were stratified by BVZ treatment status and reRT modality (SRS, HFSRT, and FSRT). Outcome variables were overall survival (OS), and progression-free survival (PFS).

RESULTS

34 of 1,742 identified articles survived inclusion criteria (2%) and reported data on 954 patients receiving reRT alone and 445 patients receiving reRT+BVZ. All patients initially underwent standard-of-care therapy for their primary HGG. In a multivariate analysis that adjusted for median patient age, WHO Grade, RT dosing, reRT fractionation regimen, time between primary and reRT, and reRT target volume, BVZ therapy was associated with significantly improved OS (2.51 [0.11, 4.92] months, P=.041) but no significant improvement in PFS (1.40 [-0.36, 3.18] months, P=.099). Patients receiving BVZ also had significantly lower rates of RN (2.2% vs 9.5%, P &lt; .001).

CONCLUSIONS

Combination reRT+BVZ may improve OS and reduce rates of RN in recurrent HGG, but further controlled studies are needed to confirm these effects.

SURG-37. SYSTEMATIC REVIEW OF GAMMA-KNIFE RADIOSURGERY AND MICROSURGICAL RESECTION FOR BRAINSTEM CAVERNOUS MALFORMATIONS

BACKGROUND

Although microsurgical resection (MR) remains the gold-standard for the treatment of symptomatic cavernous malformations, some authors have proposed the use of radiosurgical Gamma-Knife Surgery (GKS) for lesions that are deep or eloquent, such as those located in the brainstem.

OBJECTIVE

Here were analyze the literature regarding patient outcomes following MR or GKS for brain stem cavernous malformations.

METHODS

This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for systematic literature review. A database search of PubMed, Scopus, Embase, and Web of Science was conducted in September 2019. This review included studies evaluating the outcomes of MR or GKS for cavernous malformations located in the brainstem.

RESULTS

Gross total resection was achieved in the majority of patients and effectively eliminated the risk of recurrent hemorrhage from the operative lesion in studies following the outcomes of MR. GKS reduces the annual hemorrhage rate for patients, although it does not eliminate the cavernous malformation. Both treatment modalities were effective in reducing prior symptomatology. Unlike resection, GKS only reduces the risk of future hemorrhage and does prevent it.

CONCLUSIONS

Both MR and GKS can improve or stabilize symptoms in patients. However, the therapeutic benefit of GKS may take months to years to take full-effect, resulting in a potential for subsequent hemorrhagic events. MR remains the best treatment option due to its ability to eliminate future bleeding events entirely and should be performed whenever gross total resection is possible.

RADT-38. ADJUVANT RADIOTHERAPY FOR INTRACRANIAL ATYPICAL AND MALIGNANT MENINGIOMAS IN ADULT PATIENTS

BACKGROUND

Meningiomas, the most common primary brain tumor, account for more than one third of all primary CNS tumors. High-grade meningiomas, WHO grade II and III, comprise between 16%-24% of total meningiomas and are more aggressive, recur more frequently, and portend a worse prognosis than WHO grade I meningiomas. Adjuvant radiation of high-grade meningiomas, while not uncommon, remains variably described in current literature. To assess our institution’s radiation protocol, we examined our cohort of over 200 high-grade meningiomas.

METHODS

We queried our hospital’s EHR system for surgically resected meningiomas from January 2013 to December 2019. Of 286 results identified, 24 patients met the inclusion criteria: 1) histologically confirmed WHO grade II or III meningioma, 2) primary resection coupled with adjuvant radiation therapy, and 3) no chemotherapy. Only one WHO grade III meningioma met inclusion criteria. Patients with NF2 were excluded. Patient demographics, radiation dosage, fraction number, and dates of surgery, radiation onset, recurrence, and most recent follow-up were recorded.

RESULTS

Median age at surgery was 56.2 years (± 11.1, range 37.8 – 81.7), and males comprised 70.8% (n = 17) of the population. Only FSRT or IMRT were employed. The most frequent dosage was 55.8 Gy across 31 fractions with a median time to radiation of 2.7 months (± 3.0, range 1.0 – 12.6). 5 out of 24 patients experienced recurrence, which did not include the WHO III tumor. Median time to recurrence was 3.0 years (± 2.0, range .3 – 5.8). Median follow up was 3.5 years (± 2.2, range .3 – 9.3).

CONCLUSIONS

A fraction of our population experienced recurrence, regardless of grade II or grade III pathology. FSRT remains a safe and effective adjuvant therapy for high-grade meningioma after surgical resection. Future prospective studies comparing differing radiation modalities should be conducted.

Psychopathy and Pride: Testing Lykken's Hypothesis Regarding the Implications of Fearlessness for Prosocial and Antisocial Behavior

Despite widespread assumptions that psychopathy is associated with serious and repeated law-breaking, individuals with psychopathic personality traits do not invariably become chronic criminal offenders. As a partial explanation for this finding, Lykken (1995) ventured that a fearless temperament underlies both psychopathic traits and heroic behavior, and that heroic individuals’ early exposure to effective socializing forces such as warm parenting or healthy self-esteem often fosters a characteristic adaption that tends to beget “successful” behaviors, thereby differentiating heroes from convicts. In this study, we investigate relations between psychopathy, principally its fearless dominance dimension, pride, and prosocial and antisocial behavior in a community sample (N = 339). Fearless dominance and self-centered impulsivity components of psychopathy yielded differential relations with authentic and hubristic pride (Tracy and Robins, 2004), such that fearless dominance was significantly positively correlated with both facets of pride while self-centered Impulsivity was significantly negatively correlated with authentic pride and significantly positively correlated with hubristic pride. Further, authentic pride moderated (potentiated) the relation between fearless dominance and transformational leadership, one of the two outcome measures for prosocial behavior employed in our investigation. Authentic pride did not moderate the relations between fearless dominance and either our other measure of prosocial behavior (heroism) or antisocial behavior, nor did positive parenting moderate the relations between psychopathy components and social behavior. Unexpectedly, hubristic pride significantly moderated the relation between impulsive-antisocial features and antisocial behavior in a protective manner.

Acetaldehyde exchange above a managed temperate mountain grassland

An overview of acetaldehyde exchange above a managed temperate mountain grassland in Austria over four growing seasons is presented. The meadow acted as a net source of acetaldehyde in all four years, emitting between 7 and 28 mg C m-2 over the whole growing period. The cutting of the meadow resulted in huge acetaldehyde emission bursts on the day of harvesting or one day later. During undisturbed conditions, both uptake and emission fluxes were recorded. The bidirectional nature of acetaldehyde fluxes was also reflected by clear diurnal cycles during certain time periods, indicating strong deposition processes before the 1st cut and emission towards the end of the growing season. The analysis of acetaldehyde compensation points revealed a complex relationship between ambient acetaldehyde mixing ratios and respective fluxes, significantly influenced by multiple environmental parameters and variable throughout the year. As a major finding of this study, we identified both a positive and negative correlation between concentration and flux on a daily scale, where soil temperature and soil water content were the most significant factors in determining the direction of the slope. In turn, this bidirectional relationship on a daily scale resulted in compensation points between 0.40 ppbv and 0.54 ppbv, which could be well explained by collected ancillary data. We conclude that in order to model acetaldehyde fluxes at the site in Neustift on a daily scale over longer time periods, it is crucial to know the type of relationship, i.e. the direction of the slope, between mixing ratios and fluxes on a given day.

Organ and gestational age effects of maternal nutrient restriction on global methylation in fetal baboons

BACKGROUND

A sub-optimal intrauterine environment alters the trajectory of fetal development with profound effects on life-time health. Altered methylation, a proposed epigenetic mechanism responsible for these changes, has been studied in non-primate species but not nonhuman primates. We tested the hypotheses that global methylation in fetal baboon demonstrates organ specificity, gestational age specificity, and changes with maternal nutritional status.

METHODS

We measured global DNA methylation in fetuses of control fed (CTR) and nutrient restricted mothers fed 70% of controls (MNR) for brain, kidney, liver and heart at 0.5 and 0.9 gestation (G).

RESULTS

We observed organ and gestation specific changes that were modified by maternal diet. Methylation in CTR fetuses was highest in frontal cortex and lowest in liver. MNR decreased methylation in 0.5G kidney and increased methylation in 0.9G kidney and frontal cortex.

CONCLUSION

These results demonstrate a potential epigenetic mechanism whereby reduced maternal nutrition has long-term programming effects on fetal organ development.