Faculty Bibliography

OBJECTIVE:Limited evidence guides the optimal timing of treatment after the detection of tumor growth during the observation of sporadic vestibular schwannoma (VS). The current work aimed to inform the timing of radiosurgical intervention based on an analysis of patient outcomes among those who ultimately failed stereotactic radiosurgery (SRS) and underwent salvage microsurgery. STUDY DESIGN/METHODS:A historical cohort study. SETTING/METHODS:Seven centers across the United States and Norway. METHODS:Adults with sporadic VS who underwent salvage microsurgery following failed primary SRS were included. The primary outcome of interest was the association between tumor size at the time of primary SRS and the ability to achieve gross total resection (GTR) and maintain postoperative House-Brackmann (HB) facial nerve grade I at the last follow-up after salvage microsurgery. RESULTS:Among 96 patients, the median (interquartile range [IQR]) cerebellopontine angle (CPA) tumor size at primary SRS was 14.5 mm (10.0-19.0). Each 1-mm increase in CPA tumor size at the time of primary SRS was associated with a 13% increased likelihood of near-total/subtotal resection or most recent postoperative HB grade >I (odds ratio [OR] 1.13, 95% confidence interval [CI] 1.05-1.21, P = .001), with an optimal tumor size threshold to distinguish this outcome of 12 mm of CPA extension (c-index 0.73). Similarly, for each 1-mm increase in CPA tumor size at the time of primary SRS, a 9% increase in any postoperative complication with salvage microsurgery was observed (OR 1.09, 95% CI 1.02-1.15, P = .009). CONCLUSION/CONCLUSIONS:Corroborated by size threshold surveillance data informing the timing of primary microsurgical resection, the current study suggests that VS outcomes are optimized when primary radiosurgical intervention is undertaken on growing tumors when they harbor 10-15 mm of cerebellopontine angle extension or less.

Inhibitory interneurons are highly heterogeneous circuit elements often characterized by cell biological properties, but how these factors relate to specific roles underlying complex behavior remains poorly understood. Using chronic silicon probe recordings, we demonstrate that distinct interneuron groups perform different inhibitory roles within HVC, a song production circuit in the zebra finch forebrain. To link these functional subtypes to molecular identity, we performed two-photon targeted electrophysiological recordings of HVC interneurons followed by post hoc immunohistochemistry of subtype-specific markers. We find that parvalbumin-expressing interneurons are highly modulated by sensory input and likely mediate auditory gating, whereas a more heterogeneous set of somatostatin-expressing interneurons can strongly regulate activity based on arousal. Using this strategy, we uncover important cell-type-specific network functions in the context of an ethologically relevant motor skill.

Current models of eye movement control propose that motor neurons responsible for moving the eyes contribute to all eye movements, regardless of context. A recent study in larval zebrafish has instead identified specialized neural circuits, including subtypes of motor neurons, for two different types of fast eye movement, one for exploration and the other for hunting.

OBJECTIVES/OBJECTIVE:Recent studies suggest that hearing loss is associated with balance dysfunction and an increased risk of falls. The purpose of this study was to investigate whether adults with unilateral hearing loss (UHL) have an underlying vestibular dysfunction and whether vestibular testing explains balance function and fall risk. STUDY DESIGN/METHODS:Cross-sectional. SETTING/METHODS:Urban otology practice and a human motion laboratory. PATIENTS/METHODS:We recruited 41 healthy controls (mean age, 52 years; range, 22-78 years) and 29 adults with stable UHL (mean age, 53 years; range, 18-80 years) who denied symptoms of dizziness (Dizziness Handicap Inventory average, 1.86; range, 0-14). UHL occurred an average of 4 years (range from sudden loss, 4 months to 27.5 years) prior to testing. INTERVENTIONS/METHODS:We conducted the caloric portion of the videonystagmography test, video head impulse test (vHIT), and a battery of balance tests: standing on foam with eyes closed, timed up and go test, four square step test, 10-meter walk, and a virtual reality (VR) assessment of postural control. MAIN OUTCOME MEASURES/METHODS:Hearing was quantified by four-frequency pure-tone average (PTA). Caloric weakness was defined as asymmetry greater than 25%. Participants self-reported falls over the past 12 months and history of vertigo. Performance on balance tests was quantified by time to completion or duration of hold. Performance on the VR assessment was quantified by root-mean-square velocity of head sway. RESULTS:Proportion of unilateral caloric weakness was significantly higher in the UHL group (25%) than the control group (12%). Five participants with UHL refused caloric testing. vHIT gains of lateral canals were normal in both groups. The majority of participants in the UHL group experienced vertigo at the onset of hearing loss (72%). There were five fallers in the UHL group (17%) and three in the control group (7%). Participants with caloric weakness or vertigo at onset did not differ from those without in age or in any of the balance tests. Participants with history of falls differed in head sway and duration of hold standing on foam with eyes closed. CONCLUSIONS:Individuals with UHL are more likely to have caloric weakness than healthy controls; however, these findings are not correlated with functional outcomes or history of falls. Postural control testing using virtual reality or standing on foam with eyes closed may help detect those at a risk for falls.

PURPOSE/OBJECTIVE:Fear of recurrence (FoR) is a prevalent and difficult experience among cancer patients. Most research has focused on FoR among breast cancer patients, with less attention paid to characterizing levels and correlates of FoR among oral and oropharyngeal cancer survivors. The purpose was to characterize FoR with a measure assessing both global fears and the nature of specific worries as well as evaluate the role of sociodemographic and clinical factors, survivorship care transition practices, lifestyle factors, and depressive symptoms in FoR. METHODS:Three hundred eighty-nine oral and oropharyngeal survivors recruited from two cancer registries completed a survey assessing demographics, cancer treatment, symptoms, alcohol and tobacco use, survivorship care practices, depression, and FoR. RESULTS:Forty percent reported elevated global FoR, with similar percentages for death (46%) and health worries (40.3%). Younger, female survivors and survivors experiencing more physical and depressive symptoms reported more global fears and specific fears about the impact of recurrence on roles, health, and identity, and fears about death. Depression accounted for a large percent of the variance. Lower income was associated with more role and identity/sexuality worries, and financial hardship was associated with more role worries. CONCLUSIONS:FoR is a relatively common experience for oral and oropharyngeal cancer survivors. Many of its correlates are modifiable factors that could be addressed with multifocal, tailored survivorship care interventions. IMPLICATIONS FOR CANCER SURVIVORS/CONCLUSIONS:Assessing and addressing depressive symptoms, financial concerns, expected physical symptoms in the first several years of survivorship may impact FoR among oral and oropharyngeal cancer survivors.

INTRODUCTION/BACKGROUND:Tracheostomy is a commonly performed procedure in Otolaryngology and can be performed in different settings. We evaluate patient characteristics and cost efficacy of tracheostomy at the bedside versus operating room (OR). MATERIALS AND METHODS/METHODS:Retrospective chart review was performed for adult intensive care unit (ICU) patients who underwent tracheostomy from 2020 to 2023. Data and cost of procedures were analyzed using descriptive statistics. RESULTS:One hundred and sixty-five patients were included. One hundred and thirty-four (81.2%) patients underwent bedside tracheostomy. Age, sex, and BMI were not significantly different. Average time from consult to procedure and operative time was significantly shorter (p = 0.03; 0.008). There were no differences in postoperative complications, 30-day mortality, ICU length of stay (LOS), or overall LOS. Tracheostomy at the bedside offered a 73.1% cost reduction compared with performed in the OR. CONCLUSION/CONCLUSIONS:Advantages of bedside tracheostomy include decreased operative time, time from consult to procedure, and cost reduction for the hospital system. We advocate for consideration of bedside tracheostomy when appropriate.

Motor neurons have highly diverse anatomical, functional and molecular features, and differ significantly in their susceptibility in disease. Extraocular motor neurons, residing in the oculomotor, trochlear and abducens cranial nuclei (nIII, nIV and nVI), control eye movements. Recent work has begun to clarify the developmental mechanisms by which functional diversity among extraocular motor neurons arises. However, we know little about the role and consequences of extraocular motor neuron diversity in eye movement control. Here, we highlight recent work investigating the anatomical, functional and molecular features of extraocular motor neurons. Further, we frame hypotheses where studying ocular motor circuits in the larval zebrafish is poised to illuminate the consequences of motor neuron diversity for behavior.

The adoption of large language models (LLMs) in healthcare demands a careful analysis of their potential to spread false medical knowledge. Because LLMs ingest massive volumes of data from the open Internet during training, they are potentially exposed to unverified medical knowledge that may include deliberately planted misinformation. Here, we perform a threat assessment that simulates a data-poisoning attack against The Pile, a popular dataset used for LLM development. We find that replacement of just 0.001% of training tokens with medical misinformation results in harmful models more likely to propagate medical errors. Furthermore, we discover that corrupted models match the performance of their corruption-free counterparts on open-source benchmarks routinely used to evaluate medical LLMs. Using biomedical knowledge graphs to screen medical LLM outputs, we propose a harm mitigation strategy that captures 91.9% of harmful content (F1 = 85.7%). Our algorithm provides a unique method to validate stochastically generated LLM outputs against hard-coded relationships in knowledge graphs. In view of current calls for improved data provenance and transparent LLM development, we hope to raise awareness of emergent risks from LLMs trained indiscriminately on web-scraped data, particularly in healthcare where misinformation can potentially compromise patient safety.

The endoscopic transsphenoidal approach (ETSA) is a commonly used technique that allows for the minimally invasive removal of sellar and parasellar lesions. Augmented reality (AR) applications in ETSA are hypothesized to enhance intraoperative visualization by integrating a 3D-reconstructed model into the operative field. This study describes the workflow and surgical outcomes associated with the Endoscopic Surgical Navigation Advanced Platform (EndoSNAP, Surgical Theater, Cleveland, OH, USA), an AR platform designed for surgical planning and intraoperative navigation in ETSA for sellar and parasellar lesions. We analyzed a cohort of patients who underwent ETSA tumor resection using EndoSNAP. Preoperative MRI and CT scans were reconstructed and merged into a single 360° AR model using the Surgical Rehearsal Platform software. The model was then imported into EndoSNAP, which was integrated with the endoscope and neuronavigation system for real-time intraoperative use. Patient demographics, tumor characteristics, extent of resection (EOR), and endocrinologic and neurologic outcomes were recorded. Eighteen adult patients with newly diagnosed (83%) and recurrent (17%) tumors were included. Pathologies consisted of pituitary adenoma (72%), craniopharyngioma (11%), meningioma (11%), and chordoma (6%). Optic compression was present in 56% of patients, with preoperative visual deficits in 70% of them. Cavernous sinus invasion was observed in 17% of tumors. Preoperative hormonal excess and insufficiency were noted in 56% and 28% of cases, respectively. The mean preoperative tumor volume was 21.4 ± 17 cm³, which decreased to 0.4 ± 0.3 cm³ postoperatively. The mean EOR was 93.6 ± 3.6%. Postoperative complications included CSF leaks requiring surgical repair (17%), seizures related to pre-existing hemispheric trauma (6%), pulmonary embolism (6%), deep venous thrombosis (6%), and sinusitis (6%). These findings suggest that AR-enhanced visualization through EndoSNAP is a feasible and potentially beneficial adjunct in ETSA for sellar and parasellar tumor resection.