A nomogram to predict long-term facial nerve function after vestibular schwannoma resection: a contemporary multi-institutional study.

OBJECTIVE: The objective of this study was to develop a nomogram to predict long-term facial nerve (FN) function after vestibular schwannoma (VS) resection. METHODS: A retrospective cohort study of two tertiary academic skull base referral centers was performed. Consecutive adults > 18 years of age with sporadic unilateral VS who underwent resection between September 2016 and May 2021 were included. FN function in the immediate postoperative period and at the most recent evaluation was measured. RESULTS: A total of 306 patients (mean age 49 years, 63% female) were included, with a mean follow-up of 18 months. The mean maximum tumor diameter was 19 mm (range 1-50 mm), and 80 (26.1%) tumors were > 25 mm. Overall, 85% of patients showed good immediate postoperative FN function (House-Brackmann [HB] grade I or II) and 89% maintained good FN function at > 12 months of follow-up. An intraoperative FN electromyographic (EMG) response ≥ 100 µV to 0.05 mA of stimulation (OR 18.6, p < 0.001) was the strongest predictor of good HB grade in the immediate postoperative period. EMG response ≥ 100 µV (OR 5.70, p < 0.001), tumor size ≤ 25 mm (OR 3.09, p < 0.05), and better immediate postoperative HB grade (OR 1.48, p = 0.005) predicted good long-term FN function on multivariable analysis. A point-of-care nomogram based on these data predicted long-term FN function with a sensitivity of 89% and specificity of 69%. CONCLUSIONS: Better immediate postoperative HB grade, intraoperative FN EMG response ≥ 100 µV, and tumor size ≤ 25 mm strongly predicted good long-term FN function after VS resection. A point-of-care nomogram based on these variables could serve as a useful tool for postoperative counseling and prognosis of long-term FN recovery.

Hypoglossal Nerve Stimulation Therapy Outcomes in Apnea- Versus Hypopnea-Predominant Patients.

OBJECTIVES: The influence of apnea- and hypopnea-predominance on hypoglossal nerve stimulation therapy outcomes (HGNS) is still poorly defined. We assessed the significance of apnea- and hypopnea-predominance in HGNS outcomes. STUDY DESIGN: Case series with chart review. SETTING: Single-institution tertiary care center. METHODS: A total of 216 subjects were included, all of which had undergone drug-induced sleep endoscopy (DISE) and HGNS implantation. Demographic and polysomnographic data were collected. The 4% apnea-hypopnea criteria were used to calculate apnea-hypopnea index (AHI). Central apneas were omitted. Univariate logistic and linear regression were used to study the association between these data and apnea-predominance and hypopnea-predominance. Kruskal-Wallis rank sum test was used to compare medians between groups for DISE collapse patterns. RESULTS: Sixty-three patients were apnea-predominant, and 153 patients were hypopnea-predominant. These 2 groups were similar demographically (p > .20). There was no significant difference in HGNS outcomes between the groups assessed using Sher20 criteria at the 1-year mark using all-night, single-setting polysomnography or home sleep studies. Apnea index (AI)/AHI and reduction in AHI from preoperative to titration were significantly associated (p = .046). The median preoperative hypopnea index was significantly lower (p = .033) in subjects with no oropharyngeal collapse than patients with partial or complete oropharyngeal collapse. There were no significant relationships between AI/AHI and the different degrees of collapse at the velopharynx, oropharynx, tongue base, or epiglottis. CONCLUSIONS: In line with CPAP, tonsillectomy, and mandibular advancement therapy studies, we found there was largely no significant difference in DISE anatomy or in HGNS treatment outcomes between apnea- and hypopnea-predominant individuals.

A Case of an Infantile Lingual Leiomyomatous Hamartoma.

Lingual leiomyomatous hamartomas are rare lesions of the tongue with largely unknown mechanisms of formation. These lesions are often asymptomatic, though they may present with symptoms, particularly relating to swallow function. Workup should include imaging of the head and neck, and diagnosis should be made histologically. Treatment is surgical excision. This case is a report of a 4-week-old female who presented for evaluation of an asymptomatic 1 × 1 cm dorsal midline tongue mass discovered at birth. The patient was monitored until the age of 9 months, at which time the mass was surgically excised. The patient had an uncomplicated postoperative course. Pathological analysis yielded a diagnosis of leiomyomatous hamartoma.

Near-Peer Teaching in Conjunction with Flipped Classroom to Teach First-Year Medical Students Basic Surgical Skills.

Background: There is increasing evidence that students are completing medical school with insufficient surgical education. Near-peer tutoring and flipped classroom formatting may be used to enhance learning while simultaneously relieving faculty burden of teaching. Here, we qualitatively evaluate a 3-month course that integrates the use of near-peer teaching and flipped classroom formatting, with the goal of increasing first-year medical students' self-perceived confidence in performing basic sutures and knot-ties as well as interest in surgery. Methods: Twenty-one first-year medical students participated in a suturing and knot-tying course led by senior medical students. The course consisted of 2-h sessions held every 2 weeks for a total of five sessions. Students were sent publicly available videos prior to each session by which to learn the upcoming techniques and received live feedback from instructors during sessions. Questionnaires were completed pre-course and post-course. Results: Compared to pre-course ratings, post-course ratings of self-perceived confidence to perform various knot-ties and sutures all increased significantly (p < 0.05). All students stated that the course strengthened their desire to pursue a career in surgery. Student feedback of the course was overall positive. Conclusions: Near-peer teaching can be used in conjunction with flipped classroom to increase first-year medical students' self-perceived confidence in surgical suturing and knot-tying as well as interest in surgery. This curriculum may serve as an outline for student-led courses at other institutions.

Vesicular Stomatitis Virus and DNA Vaccines Expressing Zika Virus Nonstructural Protein 1 Induce Substantial but Not Sterilizing Protection against Zika Virus Infection.

The nonstructural protein 1 (NS1) of several flaviviruses, including West Nile, dengue, and yellow fever viruses, is capable of inducing variable degrees of protection against flavivirus infection in animal models. However, the immunogenicity of NS1 protein of Zika virus (ZIKV) is less understood. Here, we determined the efficacy of ZIKV NS1-based vaccine candidates using two delivery platforms, methyltransferase-defective recombinant vesicular stomatitis virus (mtdVSV) and a DNA vaccine. We first show that expression of ZIKV NS1 could be significantly enhanced by optimizing the signal peptide. A single dose of mtdVSV-NS1-based vaccine or two doses of DNA vaccine induced high levels of NS1-specfic antibody and T cell immune responses but provided only partial protection against ZIKV viremia in BALB/c mice. In Ifnar1-/- mice, neither NS1-based vaccine provided protection against a lethal high dose (105 PFU) ZIKV challenge, but mtdVSV-NS1-based vaccine prevented deaths from a low dose (103 PFU) challenge, though they experienced viremia and body weight loss. We conclude that ZIKV NS1 alone conferred substantial, but not complete, protection against ZIKV infection. Nevertheless, these results highlight the value of ZIKV NS1 for vaccine development.IMPORTANCE Most Zika virus (ZIKV) vaccine research has focused on the E or prM-E proteins and the induction of high levels of neutralizing antibodies. However, these ZIKV neutralizing antibodies cross-react with other flaviviruses, which may aggravate the disease via an antibody-dependent enhancement (ADE) mechanism. ZIKV NS1 protein may be an alternative antigen for vaccine development, since antibodies to NS1 do not bind to the virion, thereby eliminating the risk of ADE. Here, we show that recombinant VSV and DNA vaccines expressing NS1, alone, confer partial protection against ZIKV infection in both immunocompetent and immunodeficient mice, highlighting the value of NS1 as a potential vaccine candidate.

N6-methyladenosine modification enables viral RNA to escape recognition by RNA sensor RIG-I.

Internal N6-methyladenosine (m6A) modification is one of the most common and abundant modifications of RNA. However, the biological roles of viral RNA m6A remain elusive. Here, using human metapneumovirus (HMPV) as a model, we demonstrate that m6A serves as a molecular marker for innate immune discrimination of self from non-self RNAs. We show that HMPV RNAs are m6A methylated and that viral m6A methylation promotes HMPV replication and gene expression. Inactivating m6A addition sites with synonymous mutations or demethylase resulted in m6A-deficient recombinant HMPVs and virion RNAs that induced increased expression of type I interferon, which was dependent on the cytoplasmic RNA sensor RIG-I, and not on melanoma differentiation-associated protein 5 (MDA5). Mechanistically, m6A-deficient virion RNA induces higher expression of RIG-I, binds more efficiently to RIG-I and facilitates the conformational change of RIG-I, leading to enhanced interferon expression. Furthermore, m6A-deficient recombinant HMPVs triggered increased interferon in vivo and were attenuated in cotton rats but retained high immunogenicity. Collectively, our results highlight that (1) viruses acquire m6A in their RNA as a means of mimicking cellular RNA to avoid detection by innate immunity and (2) viral RNA m6A can serve as a target to attenuate HMPV for vaccine purposes.

A Lactic Acid Bacteria (LAB)-Based Vaccine Candidate for Human Norovirus.

Human noroviruses (HuNoVs) are responsible for more than 95% of the non-bacterial acute gastroenteritis epidemics in the world. The CDC estimates that every year 21 million individuals suffer from HuNoV-induced gastroenteritis in the United States. Currently, there is no FDA-approved vaccine for HuNoVs. Development of an effective vaccine has been hampered by the lack of an efficient cell culture system for HuNoVs and a suitable small animal model for pathogenesis study. In this study, we developed lactic acid bacteria (LAB) as a vector to deliver HuNoV antigen. A LAB strain (Lactococcus lactis) carrying VP1 gene of a HuNoV GII.4 virus (LAB-VP1) was constructed. It was found that HuNoV VP1 protein was highly expressed by LAB vector and was secreted into media supernatants. To test whether LAB-based HuNoV vaccine candidate is immunogenic, 4-day-old gnotobiotic piglets were orally inoculated with various doses of LAB-VP1. It was found that LABs were persistent in the small intestine of piglets and shed in pig feces for at least 25 days post inoculation. LAB DNA and VP1 were detected in mesenteric lymph nodes and spleen tissue in LAB-VP1 inoculated groups. HuNoV-specific IgG and IgA were detectable in serum and feces respectively at day 13 post-inoculation, and further increased at later time points. After being challenged with HuNoV GII.4 strain, a large amount of HuNoV antigens were observed in the duodenum, jejunum, and ileum sections of the intestine in the LAB control group. In contrast, significantly less, or no, HuNoV antigens were detected in the LAB-VP1 immunized groups. Collectively, these results demonstrate that a LAB-based HuNoV vaccine induces protective immunity in gnotobiotic piglets.