Citations

Objective/HypothesisAneurysmal bone cysts (ABCs) are benign, lytic bone lesions, which rarely present in the paranasal sinuses. There is no published consensus on the appropriate diagnostic or treatment approach. Our objective was to elucidate the clinical behavior, treatment, and outcomes for patients with ABCs of the paranasal sinuses (psABCs).Study DesignRetrospective case series and system review of the literature.MethodsA retrospective chart review was performed to identify patients evaluated at the authors' institution with psABC and consolidated with literature reports of psABC.ResultsEighty‐nine patients met inclusion criteria. The most common presenting symptom was painless facial swelling (n = 35, 39%). The ethmoid sinuses were the most common site involved (n = 55, 62%). Surgical approach was reported in 74 cases including 20 endoscopic and 54 with an open or combined approach. Fifty‐nine patients (71%) underwent gross total resection. Follow up data was reported for 67 patients. Fifteen patients (22%) were found to have recurrence or progression at follow up; 10/15 (66%) patients within the first 12 months, 14/15 (93%) within the first 24 months, and 1/15 (7%) greater than 24 months after treatment. Patients were more likely to have recurrence/progression if they presented with nasal discharge (P = .05), proptosis (P = .01), or orbital involvement (P = .03).ConclusionspsABCs typically present with painless swelling or nasal obstruction. Orbital involvement is a negative prognostic indicator with these patients more likely to have recurrence after treatment. Recurrence or progression of disease is most likely to occur within 2 years after treatment. Therefore, patients should be monitored closely during this time.Level of Evidence4 Laryngoscope, 131:E2525–E2533, 2021

Abstract Background 3D printing—also known as additive manufacturing—has a wide range of applications. Reproduction of low-cost, high-fidelity, disease- or patient-specific models presents a key developmental area in simulation and education research for complex cranial surgery. Methods Using cadaveric dissections as source materials, skull base models were created, printed, and tested for educational value in teaching complex cranial approaches. In this pilot study, assessments were made on the value of 3D printed models demonstrating the retrosigmoid and posterior petrosectomy approaches. Models were assessed and tested in a small cohort of neurosurgery resident subjects (n = 3) using a series of 10 radiographic and 2 printed case examples, with efficacy determined via agreement survey and approach selection accuracy. Results All subjects indicated agreement or strong agreement for all study endpoints that 3D printed models provided significant improvements in understanding of neuroanatomic relationships and principles of approach selection, as compared to 2D dissections or patient cross-sectional imaging alone. Models were not superior to in-person hands-on teaching. Mean approach selection accuracy was 90% (±13%) for 10 imaging-based cases, or 92% (±7%) overall. Trainees strongly agreed that approach decision-making was enhanced by adjunctive use of 3D models for both radiographic and printed cases. Conclusion 3D printed models incorporating skull base approaches and/or pathologies provide a compelling addition to the complex cranial education armamentarium. Based on our preliminary analysis, 3D printed models offer substantial potential for pedagogical value as dissection guides, adjuncts to preoperative study and case preparation, or tools for approach selection training and evaluation.

Abstract Objective Vestibular schwannoma (VS) treated with Gamma Knife stereotactic radiosurgery (SRS) was typically performed at 50% isodose line (IDL50); however, the impact of IDL variation on outcomes is poorly understood. This study aimed to compare tumor control (TC) and toxicities between treatment at 40% (IDL40) and 50% (IDL50). Methods Sporadic/unilateral VS patients treated with SRS dose 12 to 14 Gy and prescription isodose volume ≤10cm3 were included. Propensity score matching was applied to IDL40 cohort to generate an IDL50 companion cohort, adjusting for age and prescription isodose volume. After exclusion of patients with follow-up <24 months, there were 30 and 28 patients in IDL40 and IDL50 cohorts, respectively. Results Median follow-up time was 96 months (24–225 months). Actuarial and radiographic TC rates were 91.8% and clinical TC was 96.2% both at 5 and 10 years. TC was higher in IDL40 cohort but not significant (96.4 vs. 86.7%; p = 0.243). Hearing preservation (HP) rates were 71.9 and 39.2% at 5- and 10-year intervals, with significantly higher rates of HP noted in IDL40 cohort (83.3 vs. 57.1% at 5-year interval; 62.5 vs. 11.4% at 10-year interval; p = 0.017). Permanent facial neuropathy occurred in two patients, both from the IDL50 cohort (3.5%). Rates of post-SRS steroid treatment or shunt placement for hydrocephalus were slightly higher in IDL50 patients (6.9 vs. 17.9%; p = 0.208 and 3.3 vs. 7.1%; p = 0.532). Conclusion For treatment of VS with SRS, dose prescription at IDL40 or IDL50 provides excellent long-term TC and toxicity profiles. IDL40 may be associated with improved long-term HP.

ObjectiveThe degree to which various treatment modalities modify vestibular schwannoma (VS)–associated symptoms has received limited attention. The purpose of this study was to determine how different treatment modalities affect subjective symptoms in those presenting with VS.Study DesignProspective survey.SettingTertiary neurotology referral center.MethodsPatients with sporadic VS who received treatment at our institution were prospectively surveyed with a VS symptom questionnaire. Those who completed a baseline survey prior to treatment and at least 1 posttreatment survey were included. The prospective survey evaluated the severity of self‐reported symptoms (Likert scale, 1‐10), including tinnitus, dizziness or imbalance, headaches, and hearing loss.ResultsA total of 244 patients were included (mean age, 57 years). The mean duration of follow‐up was 2.1 years, and the median number of surveys completed was 2 (interquartile range, 1‐3). Seventy‐eight (32%) cases were managed with observation, 118 (48%) with microsurgery, and 48 (20%) with radiosurgery. Multivariable analyses revealed no statistically significant difference in the change in tinnitus (P =. 15), dizziness or imbalance (P = 0.66), or headaches (P =. 24) among treatment groups. Evaluation of clinically important differences demonstrated that microsurgery leads to significant bidirectional changes in headaches.ConclusionsLimited prospective data exist regarding the progression or resolution of subjective symptoms in those presenting with VS. This study suggests that tinnitus, dizziness or imbalance, and headaches are unlikely to be significantly modified by treatment modality and generally should not be used to direct treatment choice.

Abstract BACKGROUND The lateral craniopharyngeal or Sternberg's canal (SC) originates from superior orbital fissure (SOF) and traverses the sphenoid body into the nasopharynx. A remnant of the canal, Sternberg's defect (SD), has been debated as a source of cerebrospinal fluid (CSF) leak. The canal was described in 1888, and there is limited accurate visual illustration in the literature. OBJECTIVE To provide a detailed anatomic and radiological illustration of the canal in pediatric and adult population including the mechanism undermining the incidence of the canal, and the possibility of the canal as a source of CSF leak. METHODS A total of 195 high-resolution computed tomographies (CT) of patients (50 3-yr-old, 20 5-yr-old, and 125 adults) and 43 dry adult skulls (86 sides) were analyzed for a canal matching the description of the SC. RESULTS A SC was identified in 86% of the 3-yr-old and 40% of 5-yr–old patients. The diameter and length were 2.12 mm and 12 mm, respectively. The incidence of the canal decreased with age as sinus pneumatization extended into the sphenoid sinus. Only 0.8% of the adult skull on CT had the canal. The canal was not present on the dry adult skulls examination, but SD was found in 4.65%. CONCLUSION SC exists with high incidence in the pediatric group. Sinus pneumatization obliterates the canal in the adult population, leaving a defect in 4.65% of cases, which given the location and related anatomic structures, is unlikely to be a source of CSF leak.

Abstract BACKGROUND Low-grade intracranial dural arteriovenous fistulas (dAVF) have a benign natural history in the majority of cases. The benefit from treatment of these lesions is controversial. OBJECTIVE To compare the outcomes of observation versus intervention for low-grade dAVFs. METHODS We retrospectively reviewed dAVF patients from institutions participating in the CONsortium for Dural arteriovenous fistula Outcomes Research (CONDOR). Patients with low-grade (Borden type I) dAVFs were included and categorized into intervention or observation cohorts. The intervention and observation cohorts were matched in a 1:1 ratio using propensity scores. Primary outcome was modified Rankin Scale (mRS) at final follow-up. Secondary outcomes were excellent (mRS 0-1) and good (mRS 0-2) outcomes, symptomatic improvement, mortality, and obliteration at final follow-up. RESULTS The intervention and observation cohorts comprised 230 and 125 patients, respectively. We found no differences in primary or secondary outcomes between the 2 unmatched cohorts at last follow-up (mean duration 36 mo), except obliteration rate was higher in the intervention cohort (78.5% vs 24.1%, P < .001). The matched intervention and observation cohorts each comprised 78 patients. We also found no differences in primary or secondary outcomes between the matched cohorts except obliteration was also more likely in the matched intervention cohort ( P < .001). Procedural complication rates in the unmatched and matched intervention cohorts were 15.4% and 19.2%, respectively. CONCLUSION Intervention for low-grade intracranial dAVFs achieves superior obliteration rates compared to conservative management, but it fails to improve neurological or functional outcomes. Our findings do not support the routine treatment of low-grade dAVFs.

Objectives/HypothesisTo examine the hearing status and aural rehabilitative profile in a national cohort of patients with sporadic vestibular schwannoma (VS).Study DesignCross‐sectional surveyMethodsA cross‐sectional survey of Acoustic Neuroma Association members diagnosed with sporadic VS was performed from February 2017 through January 2019. Self‐reported results were used to determine the aural rehabilitative profile of respondents.ResultsAmong survey respondents, 62.2% (546/878) were not using any hearing‐assistive device at time of survey. For the 37.8% (332/878) that were utilizing hearing‐assistive devices, 32.8% (109/332) reported using a behind‐the‐ear hearing aid, 23.8% (79/332) used a contralateral routing of signal (CROS) hearing aid, and 21.7% (72/332) used a bone conduction device. Notably, 41.9% (278/663) of patients who previously underwent tumor treatment reported utilizing a hearing rehabilitation device at some point during VS management compared to 27.0% (58/215) of those undergoing observation with serial imaging (P < .001). Of 275 patients with functional hearing in the ipsilateral ear, 26.5% (73/275) reported having used at least one type of hearing device; 24.0% (66/275) reported use of a conventional hearing aid, 0.7% (2/275) a CROS aid, and 0.4% (1/275) a bone conduction device. Among respondents reporting ipsilateral nonfunctional hearing, 44.9% (258/575) reported having used at least one type of hearing device; 13.0% (75/575) a CROS aid, and 12.3% (71/575) a bone conduction device.ConclusionsEven among a cohort with presumably elevated literacy surrounding hearing rehabilitation options, few patients with a history of unilateral vestibular schwannoma ultimately use hearing assistive devices long‐term, suggesting that most patients sufficiently adjust to unilateral hearing loss or are unsatisfied with the benefits achieved with current device options.Level of Evidence4 Laryngoscope, 131:1378–1381, 2021

Abstract BACKGROUND Hypopituitarism is the most frequent complication after pituitary adenoma stereotactic radiosurgery (SRS) and is correlated with increasing radiation to the pituitary gland. Biological effective dose (BED) is a dosimetric parameter that incorporates a time component to adjust for mechanisms of deoxyribonucleic acid repair activated during treatment. OBJECTIVE To assess mean gland BED as a predictor of post-SRS hypopituitarism, as compared to mean gland dose, in a contemporary cohort study of patients undergoing single-fraction SRS for pituitary adenoma. METHODS Cohort study of 97 patients undergoing single-fraction SRS from 2007 to 2014. Eligible patients had no prior pituitary irradiation, normal pre-SRS endocrine function, and >24 mo of endocrine follow-up. Cox proportional hazards analysis was used to assess mean gland dose and BED as predictors of new post-SRS hypopituitarism. RESULTS Median post-SRS follow-up was 48 mo (interquartile range [IQR], 34-68). A total of 27 patients (28%) developed new hypopituitarism at a median 22 mo (IQR, 12-36). Actuarial rates of new endocrinopathy were 17% at 2 yr (95% CI 10%-25%) and 31% at 5 yr (95% CI 20%-42%). On univariate analysis, sex ( P = .02), gland volume ( P = .03), mean gland dose ( P < .0001), and BED significantly predicted new hypopituitarism ( P < .0001). After adjusting for sex and gland volume, BED > 45 Gy 2.47 and mean gland dose > 10 Gy were significantly associated increased risk of hypopituitarism (hazard ratio [HR] = 14.32, 95% CI = 4.26-89.0, P < .0001; HR = 11.91, 95% CI = 3.54-74.0, P < .0001). CONCLUSION BED predicted hypopituitarism more reliably than mean gland dose after pituitary adenoma SRS, but additional studies are needed to confirm these results.

Objective: Limited data currently characterize management trends of sporadic vestibular schwannoma (VS) in the United States over recent decades. Serving as the primary patient support organization in the United States, the Acoustic Neuroma Association (ANA) facilitates amalgamation of data from patients treated from 1970 through January 2019. The primary objective of the current study was to characterize the evolution in the management of sporadic VS among ANA survey respondents treated over the last half-century. Study Design/Intervention: Cross-sectional survey. Setting/Patients: ANA survey respondents diagnosed with sporadic VS. Main Outcome Measures: Trends in rates of microsurgery, radiosurgery, and observation from 1970 to 2019. Results: Among 953 patients with VS responding during the study period, 876 (92%) were included. Subjects reported the following management strategies: 220 observation (25%), 454 microsurgery (52%), and 193 radiosurgery (22%). The rate of microsurgery decreased from 86–88% from 1970 to 2000 to 44% in the last decade. The proportion of VS observed increased from 7% of all tumors in the 1990s, to 14% in the 2000s, to 33% in the 2010s. The rate of radiosurgery has increased to 28% in the last decades compared with 7% in the 1990s. The rate of subtotal resection in tumors > 2 cm increased from 34% in the 2000s to 60% in the 2010s (p = 0.0011). Conclusions: Overall, these data support a progression toward fewer patients treated with microsurgery in recent decades. Radiosurgery and observation became increasingly more common after the turn of the century, possibly due to better detection of small and asymptomatic tumors and a greater understanding of the natural history of disease.

Abstract Background The far-lateral approach is an effective skull base technique that provides access to the lower clivus and premedullary area. This approach is also useful for maximal visualization and resection of large posterior fossa tumors with extensive medial extension, especially when aggressive resection is ideal for a malignant tumor in a young patient, or it is technically challenging because of tumor calcification. We demonstrate a microsurgical operative video to describe technical pearls in this difficult situation. Case Presentation A 45-year-old man with history of “hoarseness” for up to two decades was presented with imbalance and mild dysphagia over 3 years. Imaging demonstrated a 55-mm left cerebellopontine angle (CPA) tumor extending medially across the midline with severe calcification (Figs. 1 and 2). His neurological examination revealed left facial numbness, complete left facial weakness, left deafness, complete left vocal paralysis, as well as severe left hemibody ataxia. The tumor was resected via a left suboccipital craniotomy with far lateral approach including drilling to the occipital condyle and C1 laminectomy. Initial manipulation of the inferior pole of the tumor resulted in asystole which was managed successfully with glycol pyrolate. Pathology demonstrated IDH-1 wild type, MGMT-methylated glioblastoma. The patient subsequently underwent adjuvant chemoradiation. Conclusion The far-lateral approach is an effective approach for maximal safe resection of a malignant brainstem, cerebellar, and CPA tumor.The link to the video can be found at: https://youtu.be/AIGebJPJEnw.