Proton versus photon adjuvant radiotherapy: a multicenter comparative evaluation of recurrence following spinal chordoma resection

OBJECTIVE

Chordomas are rare tumors of the skull base and spine believed to arise from the vestiges of the embryonic notochord. These tumors are locally aggressive and frequently recur following resection and adjuvant radiotherapy. Proton therapy has been introduced as a tissue-sparing option because of the higher level of precision that proton-beam techniques offer compared with traditional photon radiotherapy. This study aimed to compare recurrence in patients with chordomas receiving proton versus photon radiotherapy following resection by applying tree-based machine learning models.

METHODS

The clinical records of all patients treated with resection followed by adjuvant proton or photon radiotherapy for chordoma at Mayo Clinic were reviewed. Patient demographics, type of surgery and radiotherapy, tumor recurrence, and other variables were extracted. Decision tree classifiers were trained and tested to predict long-term recurrence based on unseen data using an 80/20 split.

RESULTS

Fifty-three patients with a mean ± SD age of 55.2 ± 13.4 years receiving surgery and adjuvant proton or photon therapy to treat chordoma were identified; most patients were male. Gross-total resection was achieved in 54.7% of cases. Proton therapy was the most common adjuvant radiotherapy (84.9%), followed by conventional or external-beam radiation therapy (9.4%) and stereotactic radiosurgery (5.7%). Patients receiving proton therapy exhibited a 40% likelihood of having recurrence, significantly lower than the 88% likelihood observed in those treated with nonproton therapy. This was confirmed on logistic regression analysis adjusted for extent of tumor resection and tumor location, which revealed that proton adjuvant radiotherapy was associated with a decreased risk of recurrence (OR 0.1, 95% CI 0.01-0.71; p = 0.047) compared with photon therapy. The decision tree algorithm predicted recurrence with an accuracy of 90% (95% CI 55.5%-99.8%), with the lowest risk of recurrence observed in patients receiving gross-total resection with adjuvant proton therapy (23%).

CONCLUSIONS

Following resection, adjuvant proton therapy was associated with a lower risk of chordoma recurrence compared with photon therapy. The described machine learning models were able to predict tumor progression based on the extent of tumor resection and adjuvant radiotherapy modality used.

Posttraumatic Transient Neurologic Dysfunction: A Proposal for Pathophysiology

Unexplained neurological deterioration is occasionally observed in patients with traumatic brain injuries. We aimed to describe the clinical features of posttraumatic transient neurologic dysfunction and provide new insight into its pathophysiology. We retrospectively collected data from patients with focal neurologic deterioration of unknown origin during hospitalization for acute traumatic brain injury for 48 consecutive months. Brain imaging, including CT, diffusion weighted imaging and perfusion weighted imaging, and electroencephalography were conducted during the episodes. Fourteen (2.0%) patients experienced unexplained focal neurologic deterioration among 713 patients who were admitted for traumatic intracranial hemorrhage during the study period. Aphasia was the predominant symptom in all patients, and hemiparesis or hemianopia was accompanied in three patients. These symptoms developed within fourteen days after trauma. Structural imaging did not show any significant interval change, and electroencephalography showed persistent arrhythmic slowing in the corresponding hemisphere in most patients. Perfusion imaging revealed increased cerebral blood flow in the symptomatic hemisphere. Surgical intervention and anti-seizure medications were ineffective in abolishing the symptoms. The symptoms disappeared spontaneously after 4 hours to one month. Transient neurologic dysfunction can occur during the acute phase of traumatic brain injury. Although transient neurologic dysfunction may last longer than a typical transient ischemic attack or seizure, it eventually resolves regardless of treatment. Based on our observation, we postulate that this is a manifestation of spreading depolarization occurring in the injured brain, which is analogous to migraine aura.

Predictive Factors Affecting the Outcomes Of angiolytic Laser-Assisted Glottoplasty for Sulcus Vocalis

OBJECTIVE

Glottoplasty using an angiolytic laser is an option for the surgical treatment of sulcus vocalis. In this study, we sought to evaluate the clinical outcomes of using a 532-nm diode laser in sulcus vocalis patients and to identify predictive factors of improved voice outcomes after angiolytic laser-assisted glottoplasty.

METHODS

A total of 66 patients with sulcus vocalis who underwent laser-assisted glottoplasty with a 532-nm diode laser were included in this study.

RESULTS

3 months after surgery, GRBAS scores, patient-reported outcome measures, fundamental frequency (F0), jitter percent, and noise-to-harmonic ratio decreased significantly, while cepstral peak prominence (CPP) of vowel and sentence production increased. Patients with auditory-perceptual improvements showed greater improvement in the Voice Handicap Index (VHI) scores, F0, and CPP of vowel and sentence production compared to those with no improvement. While young male patients with preoperatively high F0 were predicted to have favorable outcomes, the type of sulcus vocalis was not predictive of treatment outcomes. Patients treated with lower laser power showed better improvement in the VHI scores postoperatively than those who received higher laser power per vocal fold. Combined injection laryngoplasty with laser glottoplasty was effective in lowering the F0, especially in male patients with high F0.

CONCLUSION

A 532-nm diode laser is useful for treating sulcus vocalis. Young male patients and individuals with preoperatively high F0 showed better voice outcomes after laser glottoplasty. Laser power and combined injection laryngoplasty are considered to affect improvement in the VHI and lowering F0 after laser glottoplasty in sulcus vocalis.

Antioxidant Efficacy of Hwangryunhaedok-tang through Nrf2 and AMPK Signaling Pathway against Neurological Disorders In Vivo and In Vitro

Alzheimer's disease (AD) is a representative cause of dementia and is caused by neuronal loss, leading to the accumulation of aberrant neuritic plaques and the formation of neurofibrillary tangles. Oxidative stress is involved in the impaired clearance of amyloid beta (Aβ), and Aβ-induced oxidative stress causes AD by inducing the formation of neurofibrillary tangles. Hwangryunhaedok-tang (HHT, Kracie K-09®), a traditional herbal medicine prescription, has shown therapeutic effects on various diseases. However, the studies of HHT as a potential treatment for AD are insufficient. Therefore, our study identified the neurological effects and mechanisms of HHT and its key bioactive compounds against Alzheimer's disease in vivo and in vitro. In a 5xFAD mouse model, our study confirmed that HHT attenuated cognitive impairments in the Morris water maze (MWM) test and passive avoidance (PA) test. In addition, the prevention of neuron impairment, reduction in the protein levels of Aβ, and inhibition of cell apoptosis were confirmed with brain tissue staining. In HT-22 cells, HHT attenuates tBHP-induced cytotoxicity, ROS generation, and mitochondrial dysfunction. It was verified that HHT exerts a neuroprotective effect by activating signaling pathways interacting with Nrf2, such as MAPK/ERK, PI3K/Akt, and LKB1/AMPK. Among the components, baicalein, a bioavailable compound of HHT, exhibited neuroprotective properties and activated the Akt, AMPK, and Nrf2/HO-1 pathways. Our findings indicate a mechanism for HHT and its major bioavailable compounds to treat and prevent AD and suggest its potential.

Delayed Pulsatile Tinnitus by an Ascending Pharyngeal Artery-Internal Jugular Vein Fistula Caused by Blunt Trauma: A Case Report and Review of the Literature

Head and neck trauma-induced pulsatile tinnitus (PT) should be approached with caution, as it can rarely be attributed to an arteriovenous fistula (AVF). We present a 26-year-old male with a history of blunt trauma who presented delayed PT with direct AVF between the ascending pharyngeal artery (APA) and the internal jugular vein (IJV). The patient underwent occlusion of the fistula with transarterial embolization using coils and PT was completely resolved, confirming successful treatment. The delayed manifestation of PT in the APA-IJV fistula is probably due to the gradual formation of a pseudoaneurysm and subsequent AVF. This case highlights the importance of investigating PT in head trauma patients, as it can be a sign of AVF and possible complications. Overall, this case contributes to understanding delayed PT with AVF and emphasizes the importance of prompt diagnosis and treatment of AVF in patients with head and neck trauma.

Management of frontal sinus trauma: a retrospective study of surgical interventions and complications

BACKGROUND

Frontal sinus injuries are relatively rare among facial bone traumas. Without proper treatment, they can lead to fatal intracranial complications, including meningitis or brain abscesses, as well as aesthetic and functional sequelae. The management of frontal sinus injuries remains controversial, with various treatment methods and outcomes being reported. This article describes the clinical characteristics, surgical methods, and outcomes among 17 patients who underwent surgery for frontal sinus injury and related complications.

CASE PRESENTATION

We retrospectively included 17 patients who underwent surgery for frontal sinus injury and its related complications at the Kangwon National University Hospital between July 2010 and September 2021. Among them, six underwent simple open reduction and fixation of the anterior wall, eight underwent sinus obliteration, and three underwent cranialization. Two patients who underwent sinus obliteration died due to infection-related complications. The patient who underwent cranialization reported experiencing chronic headache and expressed dissatisfaction regarding the esthetic outcomes of the forehead. Except for these three patients, the other patients achieved satisfactory esthetic and functional recovery.

CONCLUSION

Active surgical management of frontal sinus injuries is often required owing to the various complications caused by these injuries; however, several factors, including the fracture type, clinical presentation, related craniomaxillofacial injury, and medical history, should be considered while formulating the treatment plan. Surgical treatment through the opening of the frontal sinus should be actively considered in patients with severely damaged posterior wall fractures and those at risk of developing infection.

Atypical case of bow hunter's syndrome linked to aberrantly coursing vertebral artery: A case report

BACKGROUND

In bow hunter's syndrome (BHS), also known as rotational vertebral artery (VA) syndrome, there is dynamic/rotational compression of the VA producing vertebrobasilar insufficiency. Most occurrences involve atlantoaxial rather than mid-cervical VA compromise, the latter being rarely reported. Herein, we detail successful VA decompression at mid-cervical spine, given a departure from its usual course.

CASE SUMMARY

The patient, a 45-year-old man, presented to our hospital with occipital headache and vertigo. Computed tomography angiography showed anomalous C4 entry of right VA, with compression upon head rotation to that side. Thyroid cartilage and anterior tubercle of C5 transverse process were visibly at fault. We opted for surgery, using an anterior cervical approach to remove the anterior tubercle. Patient recovery was uneventful and brought resolution of all preoperative symptoms.

CONCLUSION

BHS is an important consideration where aberrant coursing of VA and neurologic symptoms coexist.

Combined Open and Percutaneous Plating for the Treatment of Pilon Fracture

BACKGROUND

With the advent of percutaneous plating techniques and anatomical locking plates, open plating combined with percutaneous plating may be a feasible option to reduce pilon fracture soft-tissue complications. The purpose of this study was to evaluate the outcomes of a combined open and percutaneous plating approach for the treatment of pilon fracture.

METHODS

Forty-two consecutive patients treated with a combined open and percutaneous plating approach between March of 2010 and February of 2020 for pilon fracture were reviewed retrospectively. The study population consisted of four female patients and 38 male patients with an average age of 47.5 years (range, 15-71 years). The mean follow-up duration was 25.7 months (range, 12-48 months). The combination of a small anterolateral approach and a small anteromedial approach (or a small direct medial approach) was used in all cases. A small posterolateral approach or a small posteromedial approach was added as necessary.

RESULTS

The average ranges of ankle sagittal motion and hindfoot coronal motion at 1 year postoperatively were 43.3° (range, 30°-60°) and 47.7° (range, 40°-55°), respectively. The mean 1-year postoperative visual analogue scale score and American Orthopaedic Foot and Ankle Society score were 0.90 (range, 0-4.0) and 94.5 (range, 78-100), respectively. All patients except one achieved bony union. The mean time to union (except in the one case of nonunion) was 4.5 months (range, 3-8 months). Minor wound breakdown occurred in five cases using combined approaches, but these eventually healed with local wound care. There were no major soft-tissue complications and no instances of deep infection.

CONCLUSIONS

A combined open and percutaneous plating approach is a feasible option for the treatment of pilon fracture. This combined plating technique involving a combination of a small anterolateral approach and a small anteromedial approach (or a small direct medial approach) yielded satisfactory outcomes without major soft-tissue complications.

Dynamic Fixation versus Static Screw Fixation for Syndesmosis Injuries in Pronation External Rotation Ankle Fractures: A Retrospective Case Control Study

Introduction

The current standard treatment for ankle syndesmosis injury is static screw fixation. Dynamic fixation was developed to restore the dynamic function of the syndesmosis. The purpose of this study was to determine that which of static screw fixation and dynamic fixation is better for treatment of ankle syndesmosis injury in pronation-external rotation fractures.

Materials and methods

Thirty patients were treated with dynamic fixation (DF group) and 28 patients with static screw fixation (SF group). The primary outcome was Olerud-Molander Ankle Outcome Score. The secondary outcome were Visual Analogue Scale score and American Orthopedic Foot and Ankle Society score, radiographic outcomes, complications and cost effectiveness. To evaluate the radiographic outcome, the tibiofibular clear space, tibiofibular overlap, and medial clear space were compared using the pre-operative and last follow-up plain radiographs. To evaluate the cost effectiveness, the total hospital cost was compared between the two groups.

Results

There was no significant difference in primary outcome. Moreover, there were no significant difference in secondary outcome including Visual Analogue Scale score and American Orthopedic Foot and Ankle Society score and radiographic outcome. Two cases of reduction loss and four cases of screw breakage were observed in the SF group. No complication in the DF group was observed. Dynamic fixation was more cost effective than static screw fixation with respect to the total hospital cost.

Conclusion

Although dynamic fixation provided similar clinical and radiologic outcome, dynamic fixation is more cost effective with fewer complications than static screw fixation in ankle syndesmosis injury of pronation-external rotation fractures.

Efficacy and safety of cilostazol-based triple antiplatelet therapy compared with clopidogrel-based dual antiplatelet therapy in patients with acute ST-elevation myocardial infarction undergoing percutaneous coronary intervention: A multicenter, randomized, open-label, phase 4 trial

BACKGROUND

Previous studies reported that compared to conventional dual antiplatelet therapy (DAT; aspirin + clopidogrel), triple antiplatelet therapy (TAT), involving the addition of cilostazol to DAT, had better clinical outcomes in patients with ST-elevation myocardial infarction (STEMI). However, the optimal duration of TAT is yet to be determined.

METHODS

In total, 985 patients with STEMI who underwent primary percutaneous coronary intervention (PCI) with drug-eluting stents (DESs) were prospectively enrolled in 15 PCI centers in South Korea and China. We randomly assigned patients into 3 groups: DAT (aspirin and clopidogrel for 12 months), TAT 1M (aspirin, clopidogrel, and cilostazol for 1 month), and TAT 6M (aspirin, clopidogrel, and cilostazol for 6 months). The primary endpoint was 1-year major adverse cardiovascular events (MACEs), defined as a composite of all-cause death, recurrent myocardial infarction, stroke, or repeat revascularization.

RESULTS

The primary endpoint did not differ among the 3 groups (8.8% in DAT, 11.0% in TAT 1M, and 11.6% in TAT 6M; hazard ratio for TAT 1M vs DAT, 1.302; 95% confidence interval [CI], 0.792-2.141; P = .297; hazard ratio for TAT 6M vs DAT, 1.358; 95% CI, 0.829-2.225; P = .225). With respect to in-hospital outcomes, more bleeding events occurred in the TAT group than in the DAT group (1.3% vs 4.7% vs 2.6%, P = .029), with no significant differences in major bleeding events. Additionally, the TAT group had a higher incidence of headaches (0% vs 1.6% vs 2.6%, P = .020).

CONCLUSIONS

The addition of cilostazol to DAT did not reduce the incidence of 1-year MACEs compared with DAT alone. Instead, it may be associated with an increased risk of drug intolerance and side effects, including in-hospital bleeding and headaches.

Telemedicine Protocols for the Management of Patients with Acute Spontaneous Intracerebral Hemorrhage in Rural and Medically Underserved Areas in Gangwon State: Recommendations for Doctors with Less Expertise at Local Emergency Rooms

Previously, we reported the concept of a cloud-based telemedicine platform for patients with intracerebral hemorrhage (ICH) at local emergency rooms in rural and medically underserved areas in Gangwon state by combining artificial intelligence and remote consultation with a neurosurgeon. Developing a telemedicine ICH treatment protocol exclusively for doctors with less ICH expertise working in emergency rooms should be part of establishing this system. Difficulties arise in providing appropriate early treatment for ICH in rural and underserved areas before the patient is transferred to a nearby hub hospital with stroke specialists. This has been an unmet medical need for decade. The available reporting ICH guidelines are realistically possible in university hospitals with a well-equipped infrastructure. However, it is very difficult for doctors inexperienced with ICH treatment to appropriately select and deliver ICH treatment based on the guidelines. To address these issues, we developed an ICH telemedicine protocol. Neurosurgeons from four university hospitals in Gangwon state first wrote the guidelines, and professors with extensive ICH expertise across the country revised them. Guidelines and recommendations for ICH management were described as simply as possible to allow more doctors to use them easily. We hope that our effort in developing the telemedicine protocols will ultimately improve the quality of ICH treatment in local emergency rooms in rural and underserved areas in Gangwon state.

Etiology of lipid-laden macrophages in the lung

Uniquely positioned as sentinel cells constantly exposed to the environment, pulmonary macrophages are vital for the maintenance of the lung lining. These cells are responsible for the clearance of xenobiotics, pathogen detection and clearance, and homeostatic functions such as surfactant recycling. Among the spectrum of phenotypes that may be expressed by macrophages in the lung, the pulmonary lipid-laden phenotype is less commonly studied in comparison to its circulatory counterpart, the atherosclerotic lesion-associated foam cell, or the acutely activated inflammatory macrophage. Herein, we propose that lipid-laden macrophage formation in the lung is governed by lipid acquisition, storage, metabolism, and export processes. The cellular balance of these four processes is critical to the maintenance of homeostasis and the prevention of aberrant signaling that may contribute to lung pathologies. This review aims to examine mechanisms and signaling pathways that are involved in lipid-laden macrophage formation and the potential consequences of this phenotype in the lung.

Surgical Intervention for Primary B-cell Lymphoma of the Spine: A Systematic Review and Meta-analysis of Clinical Presentation, Treatment, Postoperative Outcomes, and Histologic Markers

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

To perform a systematic review of the clinical symptoms, radiographic findings, and outcomes after spinal decompression in B-cell lymphoma.

SUMMARY OF BACKGROUND DATA

B-cell lymphoma is a potential cause of spinal cord compression that presents ambiguously with nonspecific symptoms and variable imaging findings. Surgical decompression is a mainstay for both diagnosis and management, especially in patients with acute neurological deficits; however, the efficacy of surgical intervention compared with nonoperative management is still unclear.

METHODS

The databases of Medline, PubMed, and the Cochrane Database of Systemic Reviews were queried for all articles reporting spinal B-cell lymphoma. Data on presenting symptoms, treatments, survival outcomes, and histologic markers were extracted. Using the R software "survival" package, we generated bivariate and multivariate Cox survival regression models and Kaplan-Meier curves.

RESULTS

In total, 65 studies were included with 72 patients diagnosed with spinal B-cell lymphoma. The mean age was 56.22 (interquartile range: 45.00-70.25) with 68% of patients being males and 4.2% of patients being immunocompromised. Back pain was the most common symptom (74%), whereas B symptoms and cauda equina symptoms were present in 6% and 29%, respectively. The average duration of symptoms before presentation was 3.81 months (interquartile range: 0.45-3.25). The most common location was the thoracic spine (53%), with most lesions being hyperintense (28%) on T2 magnetic resonance imaging. Surgical resection was performed in 83% of patients. Symptoms improved in 91% of patients after surgery and in 80% of patients treated nonoperatively. For all 72 patients, the overall survival at 1 and 5 years was 85% (95% CI: 0.749-0.953; n = 72) and 66% (95% CI: 0.512-0.847; n = 72), respectively.

CONCLUSION

Although surgery is usually offered in patients with acute spinal cord compression from B-cell lymphoma, chemotherapy and radiation alone offer a hopeful alternative to achieve symptomatic relief, particularly in patients who are unable to undergo surgery.

Comparison of Clinical Characteristics of Traumatic Brain Injury Patients According to the Mechanism Before and After COVID-19

Objective

This study investigated the change in the number of patients with head trauma according to the trauma mechanism among severely injured patients transferred to the emergency department of Wonju Severance Christian Hospital before and during the coronavirus disease 2019 (COVID-19) pandemic.

Methods

Medical records (sex, age, diagnosis, trauma mechanism, and injury severity score) of patients referred to the emergency room between January 2018 and December 2019 and January 2020 and December 2021 were retrospectively reviewed, verified, and compared.

Results

Between 2020 and 2021, the number of patients with traumatic brain injury decreased by 251 (32%). No significant differences were observed in sex, age, or time of accident. From 2020 to 2021, among the trauma mechanisms, the number of cases involving rolling down slightly reduced compared with those involving other mechanisms. Furthermore, cerebral contusions among intracranial lesions significantly increased during the COVID-19 pandemic.

Conclusion

Partial restrictions on social activities owing to COVID-19 are ongoing. Further investigation of the clinical characteristics of trauma patients over a longer period is required.

Development of Cloud-Based Telemedicine Platform for Acute Intracerebral Hemorrhage in Gangwon-do : Concept and Protocol

We aimed to develop a cloud-based telemedicine platform for patients with intracerebral hemorrhage (ICH) at local hospitals in rural and underserved areas in Gangwon-do using artificial intelligence and non-face-to-face collaboration treatment technology. This is a prospective and multi-center development project in which neurosurgeons from four university hospitals in Gangwondo will participate. Information technology experts will verify and improve the performance of the cloud-based telemedicine collaboration platform while treating ICH patients in the actual medical field. Problems identified will be resolved, and the function, performance, security, and safety of the telemedicine platform will be checked through an accredited certification authority. The project will be carried out over 4 years and consists of two phases. The first phase will be from April 2022 to December 2023, and the second phase will be from April 2024 to December 2025. The platform will be developed by dividing the work of the neurosurgeons and information technology experts by setting the order of items through mutual feedback. This article provides information on a project to develop a cloud-based telemedicine platform for acute ICH patients in Gangwon-do.

Augmented Reality in Minimally Invasive Spinal Surgery: A Narrative Review of Available Technology

INTRODUCTION

Spine surgery has undergone significant changes in approach and technique. With the adoption of intraoperative navigation, minimally invasive spinal surgery (MISS) has arguably become the gold standard. Augmented reality (AR) has now emerged as a front-runner in anatomical visualization and narrower operative corridors. In effect, AR is poised to revolutionize surgical training and operative outcomes. Our study examines the current literature on AR-assisted MISS, synthesizes findings, and creates a narrative highlighting the history and future of AR in spine surgery.

MATERIAL AND METHODS

Relevant literature was gathered using the PubMed (Medline) database from 1975 to 2023. Pedicle screw placement models were the primary intervention in AR. These were compared to the outcomes of traditional MISS RESULTS: We found that AR devices on the market show promising clinical outcomes in preoperative training and intraoperative use. Three prominent systems were as follows: XVision, HoloLens, and ImmersiveTouch. In the studies, surgeons, residents, and medical students had opportunities to operate AR systems, showcasing their educational potential across each phase of learning. Specifically, one facet described training with cadaver models to gauge accuracy in pedicle screw placement. AR-MISS exceeded free-hand methods without unique complications or contraindications.

CONCLUSIONS

While still in its infancy, AR has already proven beneficial for educational training and intraoperative MISS applications. We believe that with continued research and advancement of this technology, AR is poised to become a dominant player within the fundamentals of surgical education and MISS operative technique.

Identification of Deep Cervical Fascial Layers During Anterior Cervical Spine Exposure

BACKGROUND

Anterior approaches to the cervical spine are among the most common exposures by which neurosurgeons and orthopedic surgeons access the prevertebral space and ultimately the cervical disk and vertebral bodies. There is a paucity of literature describing the microanatomic fascial planes of the neck with respect to anterior cervical approaches.

OBJECTIVE

To delineate the microanatomic connections of the cervical fascial planes pertinent to anterior cervical exposure.

METHODS

Using a cadaveric model, original illustrations, the Visible Human Project, and an original surgical video, we demonstrate a stepwise method for identifying the correct planes for anterior cervical exposure.

RESULTS

A step-by-step method for identifying the anterior cervical fascial planes intraoperatively is demonstrated.

CONCLUSION

A comprehensive understanding of anterior cervical microsurgical anatomy is vital for performing a methodical yet efficient approach to the prevertebral space while minimizing retraction and iatrogenic injury to the surrounding neurovascular structures.

Comprehensive Index of Vocal Fatigue (CIVF): Development and Clinical Validation

OBJECTIVES

In this study, we sought to investigate whether auditory-perceptual and acoustic measures change after a passage-reading task and to develop a multidimensional index of performance fatigue in voice disorders. The clinical usefulness and cut-off scores of the newly developed index were also explored.

METHODS

A total of 150 patients (age = 35.65 ± 11.44 years) with voice disorders and 100 healthy controls (age = 35.04 ± 11.26 years) were enrolled in the study. Overall severity (OS) and acoustic measures of sentence samples were obtained before and after a passage-reading task and compared between the two positions. Acoustic features included cepstral peak prominence (CPP), σCPP, L/H spectral ratio (SR), and σSR. Using the changes (Δ) in those acoustic measures and the scores of the Vocal Fatigue Index (VFI), a predictive model of the ΔOS was established. The clinical cut-off point of the index was also identified.

RESULTS

For the patient group, OS was higher, but CPP and σCPP were lower for the rear position (after reading the passage) compared to the front position (before reading the passage). A significant portion (adjusted R² = 77.7%) of the ΔOS was predicted by ΔCPP, tiredness score of the VFI, ΔσCPP, ΔσSR, and ΔSR. The area under the curve of the newly developed index was .864 (sensitivity, 78.67%; specificity, 78.00%), and the index's criterion was >2.6489.

CONCLUSIONS

The newly developed Comprehensive Index of Vocal Fatigue (CIVF) can quantify vocal fatigue in voice disorders, reflecting both acoustic and auditory perceptual changes after a passage-reading task. Further studies should explore the responsiveness of the CIVF and the impact of related factors on the CIVF in various voice disorders.

A167 HISTOLOGICAL REMISSION PLACEBO RATES IN ULCERATIVE COLITIS TRIALS: A SYSTEMATIC REVIEW AND META-ANALYSIS

Background

High histologic remission rates have been reported with placebos in randomized controlled trials (RCTs) evaluating ulcerative colitis (UC) therapies and have varied based on trial designs. We performed a systematic review and meta-analysis to quantify placebo histological remission rates and identify factors influencing those rates.

Purpose

This systematic review aims to improve future trials design and minimize placebo rates in UC trials.

Method

MEDLINE, EMBASE, and the Cochrane library were searched from inception of the databases until December 2021. We included placebo-controlled RCTs of adult patients with UC treated with aminosalicylates, corticosteroids, immunosuppressives, biologics, and small molecules. We pooled estimates using a random-effects model and performed subgroup analysis as well as meta-regression to evaluate the effect of different covariates on placebo rates.

Result(s)

Thirty-three studies (30 induction and 3 maintenance) were included. The overall placebo histological remission rate was 15.7% [95% CI 12.9-19%] across all 33 studies (Figure). High heterogeneity was observed among studies with I² = 62.10%. In induction studies, the pooled estimate of histological remission was 15.8% [95% CI 12.7-19.5%], while in maintenance studies the pooled estimate was 14.5% [95% CI 8.4-24%]. Subgroup analysis revealed statistically significant differences in placebo rates when accounting for background medications, the intervention drug class, and disease severity [p= 0.041, 0.025, and 0.025, respectively]. There was no statistical difference between induction vs. maintenance studies or between different histological scales [p= 0.771, and 0.075, respectively]. Meta-regression showed similar results except that the therapy used was not statistically significant [p-value= 0.059].

Image

Conclusion(s)

Placebo histological remission rates range from 13-19% in UC RCTs, but studies are highly heterogeneous. Factors found to influence placebo rates include presence of background medications, the drug used and the disease severity in UC patients. These observations have important implications in informing future trial designs to minimize placebo rates and reduce heterogeneity.

Disclosure of Interest

M. Youssef: None Declared, K. Dong: None Declared, S. J. Lee: None Declared, N. Narula Speakers bureau of: received honoraria from Janssen, Abbvie, Takeda, Pfizer, Merck, Sandoz, Novartis, and Ferring

Comparison Of 3-6 Month Versus 12 Month Dual Antiplatelet Therapy After Coronary Intervention Using the Contemporary Drug-eluting Stents With Ultrathin Struts: The HOST-IDEA Randomized Clinical Trial

Background: Limited data are available on short-term dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) using third-generation drug-eluting stents (DES) with ultrathin struts and advanced polymer technology. We investigated whether 3-6 month DAPT was non-inferior to 12 month one after implantation of DES with ultrathin struts and advanced polymer technology. Methods: We performed an open-label, randomized trial at 37 centers in South Korea. We enrolled patients undergoing PCI using the Orsiro biodegradable-polymer sirolimus-eluting stents (SES) or the Coroflex ISAR polymer-free SES. Patients with ST-segment elevation myocardial infarction were excluded. Patients were randomized to receive either 3-6 month or 12 month DAPT after PCI. The choice of antiplatelet medications was at the physician's discretion. The primary outcome was a net adverse clinical event (NACE), a composite of cardiac death, target vessel myocardial infarction (TVMI), clinically driven target lesion revascularization (CD-TLR), stent thrombosis, or major bleeding, defined as Bleeding Academic Research Consortium type 3 or 5 at 12 months. The major secondary outcomes were target lesion failure (TLF), a composite of cardiac death, TVMI, CD-TLR, and major bleeding. Results: A total of 2,013 patients (mean age 65.7±10.5, 1,487 male [73.9%], 1,110 [55.1%] presented with acute coronary syndrome) were randomized to 3-6 month DAPT (n=1,002) or 12 month DAPT (n=1,011). The primary outcome occurred in 37 (3.7%) patients in the 3-6 month DAPT group and 41 (4.1%) in the 12 month DAPT group. The non-inferiority of the 3-6 month DAPT group to the 12 month DAPT group was met (absolute risk difference, -0.4% [1-sided 95% confidence interval (CI), -∞% to 1.1%; P<0.001 for non-inferiority]). There were no significant differences in TLF (hazard ratio [HR] 0.98, 95% CI 0.56-1.71, P=0.94) or major bleeding (HR 0.82, 95% CI 0.41-1.61, P=0.56) between the two groups. Across various subgroups, the treatment effect of 3-6 month DAPT was consistent for NACE. Conclusions: Among patients undergoing PCI using third-generation DES, 3-6 month DAPT was non-inferior to 12 month DAPT for NACE. Further research is needed to generalize this finding to other populations and to determine the ideal regimen for 3-6 month DAPT.

International Learner Perceptions, Educational Value, and Cost Associated With the Use of Start-to-Finish Surgical Simulation Compared With Cadaveric Models

BACKGROUND

Graduate surgical education is highly variable across regions and institutions regarding case volume and degree of trainee participation in each case. Dedicated educational curriculum using cadaveric tissue has been shown to enhance graduate surgical training, however with associated financial and utility burden to the institution.

OBJECTIVE

To investigate the utility of educational and cost applications of a novel method of combining mixed organic hydrogel polymers and 3-dimensional printed anatomic structures to create a complete "start-to-finish" simulation for resident education in spinal anatomy, instrumentation, and surgical techniques.

METHODS

This qualitative pilot study investigated 14 international participants on achievement of objective and personal learning goals in a standardized curriculum using biomimetic simulation compared with cadaveric tissue. A questionnaire was developed to examine trainee evaluation of individual anatomic components of the biomimetic simulators compared with previous experience with cadaveric tissue.

RESULTS

A total of 210 responses were acquired from 14 participants. Six participants originated from US residency education programs and 8 from transcontinental residency programs. Survey results for the simulation session revealed high user satisfaction. Score averages for each portion of the simulation session indicated learner validation of anatomic features for the simulation compared with previous cadaveric experience. Cost analysis resulted in an estimated savings of $10 833.00 for this single simulation session compared with previous cadaveric tissue sessions.

CONCLUSION

The results of this study indicate a strong potential of establishing biomimetic simulation as a cost-effective and high-quality alternative to cadaveric tissue for the instruction of fundamental spine surgical techniques.

Comparing the efficacy of different methods of faecal microbiota transplantation via oral capsule, oesophagogastroduodenoscopy, colonoscopy, or gastric tube

BACKGROUND

The increasing prevalence of multidrug-resistant organism (MDRO) carriage poses major challenges to medicine as healthcare costs increase. Recently, faecal microbiota transplantation (FMT) has been discussed as a novel and effective method for decolonizing MDRO.

AIM

To compare the efficacy of different FMT methods to optimize the success rate of decolonization in patients with MDRO carriage.

METHODS

This prospective cohort study enrolled patients with MDRO carriages from 2018 to 2021. Patients underwent FMT via one of the following methods: oral capsule, oesophagogastroduodenoscopy (EGD), colonoscopy, or gastric tube.

FINDINGS

A total of 57 patients underwent FMT for MDRO decolonization. The colonoscopy group required the shortest time for decolonization, whereas the EGD group required the longest (24.9 vs 190.4 days, P = 0.022). The decolonization rate in the oral capsule group was comparable to that in the EGD group (84.6% vs 85.7%, P = 0.730). An important clinical factor associated with decolonization failure was antibiotic use after FMT (odds ratio = 6.810, P = 0.008). All four groups showed reduced proportions of MDRO species in microbiome analysis after FMT.

CONCLUSION

Compared to other conventional methods, the oral capsule is an effective FMT method for patients who can tolerate an oral diet. The discontinuation of antibiotics after FMT is a key factor in the success of decolonization.

Increasing power generation to a single-chamber compost soil urea fuel cell for carbon-neutral bioelectricity generation: A novel approach

Microbial fuel cells (CS-UFC) utilize waste resources containing biodegradable materials that play an essential role in green energy. MFC technology generates "carbon-neutral" bioelectricity and involves a multidisciplinary approach to microbiology. MFCs will play an important role in the harvesting of "green electricity." In this study, a single-chamber urea fuel cell is fabricated that uses these different wastewaters as fuel to generate power. Soil has been used to generate electrical power in microbial fuel cells and exhibited several potential applications to optimize the device; the urea fuel concentration is varied from 0.1 to 0.5 g/mL in a single-chamber compost soil urea fuel cell (CS-UFC). The proposed CS-UFC has a high power density and is suitable for cleaning chemical waste, such as urea, as it generates power by consuming urea-rich waste as fuel. The CS-UFC generates 12 times higher power than conventional fuel cells and exhibits size-dependent behavior. The power generation increases with a shift from the coin cell toward the bulk size. The power density of the CS-UFC is 55.26 mW/m². This result confirmed that urea fuel significantly affects the power generation of single-chamber CS-UFC. This study aimed to reveal the effect of soil properties on the generated electric power from soil processes using waste, such as urea, urine, and industrial-rich wastewater as fuel. The proposed system is suitable for cleaning chemical waste; moreover, the proposed CS-UFC is a novel, sustainable, cheap, and eco-friendly design system for soil-based bulk-type design for large-scale urea fuel cell applications.

SURG-12. SURGICAL INTERVENTION FOR PRIMARY B-CELL LYMPHOMA OF THE SPINE: A SYSTEMATIC REVIEW AND META-ANALYSIS OF CLINICAL PRESENTATION, HISTOLOGICAL MARKERS, TREATMENTS, AND SURVIVAL OUTCOMES

B-cell lymphoma is a potential cause of spinal cord compression that presents with nonspecific symptoms and inconsistent imaging findings. Surgical decompression is a mainstay for both diagnosis and management especially in patients with acute neurologic deficits; however, the long-term efficacy of intervention is still unclear. We perform a systematic review of the clinical symptoms, radiographic findings, and outcome after spinal decompression in B-cell lymphoma. The databases of Medline, PubMed, and the Cochrane Database of Systemic Reviews were queried for all articles reporting spinal B-cell lymphoma. Data on presenting symptoms, histological markers, treatment and survival outcomes were extracted. Bivariate and Multivariate Cox survival regression models and Kaplan-Meier curves were generated using R software survival package. In total, 57 studies were included with 72 patients diagnosed with spinal B-cell lymphoma. Mean age was 56.22 (IQR: 45.00-70.25) with 68% of patients being male and 4.2% of patients being immunocompromised. Back pain was the most common symptom (74%) with B symptoms and cauda equina symptoms present in only 6% and 29% respectively. Mean length of symptoms before presentation was 3.81 months (IQR: 0.45-3.25). The most common location was the thoracic spine (53%), with a majority of the lesions being hyperintense (28%) on T2 MRI. Surgical resection was performed in 83% of patients. Symptoms improved in 88% of patients after surgery and 80% of patients treated nonoperatively. OS at one- and five-years was 85% (95% CI: 0.749-0.953; n=72) and 66% (95% CI: 0.512-0.847; n=72), respectively. Age &gt; 70 was associated with poorer OS in bivariate (HR 4.07 [95% CI: 1.328-12.46], p &lt; 0.01; n=72) and multivariate analysis (HR 3.829 [95% CI: 1.158-12.662], p &lt; 0.03; n=72). Primary spinal B-cell lymphoma can have a variety of presentations. Both surgery and nonoperative management may have similar improvement in symptoms. Age &gt; 70 appears to confer poorer OS.

Detection rate of MR myelography without intrathecal gadolinium in patients with newly diagnosed spontaneous intracranial hypotension

AIM

To evaluate the detection rate of magnetic resonance (MR) myelography without intrathecal gadolinium for cerebrospinal fluid (CSF) leakage in patients with newly diagnosed spontaneous intracranial hypotension (SIH) and to validate a published scoring system for predicting CSF leakage.

MATERIALS AND METHODS

This retrospective, observational, single-institution study included patients with newly diagnosed SIH between March 2015 and April 2021. Patients were included if they (a) had newly diagnosed SIH and (b) underwent initial brain MR imaging and preprocedural MR myelography with two- and three-dimensional turbo spin-echo sequences. Patients who underwent spine surgery or procedures including epidural injection and acupuncture were excluded. The detection rate was defined as the proportion of patients with a true-positive MR myelography result among all patients with confirmed CSF leakage. The interobserver agreement for the MR myelography results between two radiologists was analysed using weighted kappa statistics.

RESULTS

A total of 136 patients (mean age, 48 years; 70 women) with suspected SIH were included. Of these patients, 120 (88%, 120/136) were confirmed to have CSF leakage. Of the patients with confirmed CSF leakage, 90 (75%, 90/120) had epidural fluid collection. The detection rate of MR myelography for CSF leakage was 88% (105/120). The interobserver agreement between the two readers for detecting CSF leakage (κ = 0.76) or epidural fluid collection (κ = 0.76) on MR myelography was high. Among 24 patients with normal brain MR imaging results, 16 had CSF leakage (67%, 16/24).

CONCLUSIONS

Non-invasive MR myelography without intrathecal gadolinium should be considered to detect CSF leakage in patients with suspected SIH.

Assessment of aortic valve area on cardiac computed tomography and doppler echocardiography: differences and clinical significance in symptomatic bicuspid aortic stenosis

Backgrounds

This study aimed to investigate the differences and clinical significance of effective orifice area (EOA) on Doppler echocardiography and geometric orifice area (GOA) on cardiac computed tomography (CT) in bicuspid aortic stenosis (AS).

Methods

One-hundred sixty-three consecutive patients (age 64±10 years, 56.4% men) with symptomatic bicuspid AS who were referred for surgery and underwent both cardiac CT and echocardiography within 3 months were studied. For the aortic valve area, GOACT was measured by multiplanar CT planimetry, and EOAEcho was calculated by continuity equation with Doppler echocardiography. The associations of GOACT and EOAEcho with the patients' symptom scale, biomarkers, and left ventricular (LV) functional variables were comprehensively analyzed.

Results

There was a significant but modest correlation between EOAEcho and GOACT (r=0.604, p&lt;0.001). Both EOAEcho and GOACT revealed significant correlations with mean pressure gradient and peak transaortic velocity and the coefficients were higher in EOAEcho than GOACT. EOAEcho of 1.05 cm2 and GOACT of 1.25 cm2 correspond to the hemodynamic cut-off values for diagnosing severe AS. EOAEcho was well correlated with patients' symptom scale and log NT-pro BNP, but GOACT was not. In addition, EOAEcho showed higher correlation coefficient with estimated LV filling pressure and LV global longitudinal strain than GOACT.

Conclusions

Both EOAEcho and GOACT can be used to evaluate the severity of bicuspid AS, however, the threshold for GOACT for diagnosing severe AS should be applied higher than that for EOAEcho. EOAEcho tends to be more correlated with the patients' symptom degree, biomarkers, and LV functional variables than GOACT.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): The Korean Cardiac Research Foundation

Stent expansion evaluated by optical coherence tomography and subsequent outcomes

Background

Regarding stent expansion indexes, previous optical coherence tomography (OCT) studies have shown minimal stent area (MSA) to be most predictive of adverse events.

Purpose

We sought to evaluate the impact of various stent expansion indexes by post-stent OCT on long-term clinical outcomes, and hence to find OCT-defined optimal stent expansion criteria.

Methods

Of the patients registered in the Yonsei OCT registry, a total of 1071 patients with 1123 native coronary artery lesions treated with new-generation drug-eluting stents under the OCT guidance and analyzable final post-stent OCT were included. Stent expansion indexes and different suboptimal stent expansion criteria were evaluated for their association with device-oriented clinical endpoints (DoCE) including cardiac death, target vessel-related myocardial infarction (TVMI) or stent thrombosis, and target lesion revascularization. Major safety events (MSE) included cardiac death, TVMI or stent thrombosis.

Results

The median follow-up period was 40.6 (interquartile range 22.0–50.0) months. As a continuous variable, MSA, adaptive volumetric stent expansion (stent volume/adaptive reference lumen volume) and overall volumetric stent expansion (stent volume/post-stent lumen volume) were significantly predictive of DoCE. As a categorical criteria, MSA &lt;5.0 mm2 (hazard ratio [HR] 3.80; 95% confidence interval [CI] 1.53–9.45), MSA/distal reference lumen area &lt;90% (HR 2.13; 95% CI 1.10–4.14), and overall volumetric stent expansion ≥96.6% (HR 2.38; 95% CI 1.09–5.22) were independently associated with DoCE after adjusting for confounders, and a total malapposition volume ≥7.0 mm3 (HR 3.38; 95% CI 1.05–10.93) was linked to MSE.

Conclusions

This OCT study highlights that sufficient stent expansion to achieve adequate absolute MSA and relative MSA by distal reference lumen area and alleviate significant malapposition is important to improve clinical outcome, but overall stent overexpansion may have deleterious effect.

Funding Acknowledgement

Type of funding sources: None.

Reliability of Acoustic Measures in Dysphonic Patients With Glottic Insufficiency and Healthy Population: A COVID-19 Perspective

OBJECTIVES

The COVID-19 pandemic has affected the voice assessment protocols for dysphonic patients. In this study, we compared the changes in acoustic measures of the healthy population as well as dysphonic patients due to glottic insufficiency between the pandemic period requiring face masks and the prepandemic period when the masks were not essential. The clinical reliability of the acoustic measures with and without face masks was explored.

METHODS

A total of 120 patients (age = 42.3 ± 11.9 yrs) with glottic insufficiencies such as UVFP and sulcus vocalis and 40 healthy population (age = 40.5 ± 11.2 yrs) cohorts were enrolled during the pandemic period. Age- and gender-matched 120 patients and 40 healthy population cohorts who underwent voice assessment without face masks before the pandemic were enrolled as prepandemic controls. Acoustic measures and overall severity estimates of vowel and speech samples were compared, which included cepstral peak prominence (CPP), L/H spectral ratio (SR), their standard deviations, F0, jitter percent (Jitt), shimmer percent (Shim), noise-to-harmonic ratio (NHR), Cepstral Spectral Index of Dysphonia (CSID), and Acoustic Psychometric Severity Index of Dysphonia.

RESULTS

Both patients and healthy cohorts showed higher SRv and SRs but lower CSIDv during the pandemic compared to the prepandemic period. F0 of the healthy male controls during the pandemic was higher than during the prepandemic periods, while the CSIDs was lower for the pandemic period. The pandemic patient cohort showed lower σSRs compared to the prepandemic patient cohort. When the acoustic measures of patients were compared to the healthy population cohort, the patient cohort showed lower CPP and σCPPs, while higher σCPPv, Jitt, Shim, and NHR during both pandemic and prepandemic period. Overall, the area under the curve of the acoustic measures and overall severity estimates was similar between the mask and non-mask groups, although the AUC of the SR measures was poor.

CONCLUSIONS

Wearing face masks during the pandemic did not compromise the overall reliability of the acoustic analysis in patients with glottic insufficiency, suggesting the current protocol of acoustic analysis can be carried out reliably while wearing a mask to ensure safety in the pandemic era.

Bilateral Atypical Subtrochanteric Femoral Fractures with Primary and Secondary Bone Healing in Pycnodysostosis

ABSTRACT

Atypical subtrochanteric femoral fractures are a common problem associated with pycnodysostosis. Pycnodysostosis is a rare sclerotic bone disease caused by a mutation in the cathepsin K gene. Fracture healing in pycnodysostosis cases is typically inferior. Here, we report a case of bilateral atypical subtrochanteric femoral fractures in one patient with pycnodysostosis. The right subtrochanteric fracture was treated with open reduction and internal fixation (open plating), and united through primary bone healing, while the left one was treated with closed reduction and internal fixation (submuscular plating), and united through secondary bone healing. Although the time to bony union was delayed, fracture union after extramedullary osteosynthesis was obtained in both atypical fractures, demonstrating that both primary and secondary bone healing is possible in patients with pycnodysostosis.

LEVEL OF CLINICAL EVIDENCE

4.

Attributable Mortality and Excess Length of Stay associated with Third-Generation Cephalosporin Resistant Enterobacterales Bloodstream Infections - a prospective cohort study in Suva, Fiji

OBJECTIVES

There are scant primary clinical data on antimicrobial resistance (AMR) burden from low- and middle-income countries (LMICs). We adapted recent World Health Organization methodology to measure the impact of third-generation cephalosporin resistance (3GC-R) on mortality and excess length of hospital stay in Fiji.

METHODS

We conducted a prospective cohort study of inpatients with Enterobacterales bloodstream infections (BSIs) at Colonial War Memorial Hospital, Suva. We used cause-specific Cox proportional hazards models to estimate the effect of 3GC-R on the daily risk (hazard) of in-hospital mortality and being discharged alive (competing risks), and multistate modelling to estimate the excess length of hospital stay.

RESULTS

From July 2020 to February 2021 we identified 162 consecutive Enterobacterales BSIs, 3GC-R was present in 66 (40.7%). Crude mortality for patients with 3GC-susceptible and 3GC-R BSIs was 16.7% (16/96) and 30.3% (20/66), respectively. 3GC-R was not associated with the in-hospital mortality hazard rate (adjusted hazard ratio (aHR) 1.13, 95% CI 0.51-2.53) or being discharged alive (aHR 0.99, 95% CI 0.65-1.50), whereas Charlson comorbidity index score (aHR 1.62, 95% CI 1.36-1.93) and Pitt bacteraemia score (aHR 3.57, 95% CI 1.31-9.71) were both associated with an increased hazard rate of in-hospital mortality. 3GC-R was associated with an increased length of stay of 2.6 days (95% CI 2.5-2.8). 3GC-R was more common among hospital-associated infections, but genomics did not identify clonal transmission.

CONCLUSION

Patients with Enterobacterales BSIs in Fiji had high mortality. There were high rates of 3GC-R, which was associated with increased hospital length of stay but not with in-hospital mortality.

Mesenchymal Stem Cell Therapy for Focal Epilepsy: A Systematic Review of Preclinical Models and Clinical Studies

Drug resistant epilepsy (DRE) is characterized by recurrent seizures despite appropriate treatment with antiseizure medication (ASM). Due to their regenerative and immunomodulatory potential, therapies with biologics such as mesenchymal stem cells (MSCs) offer a potential therapeutic benefit for structural causes of epilepsy, such as hippocampal sclerosis. In this manuscript, we report a systematic review of the literature evaluating the preclinical and clinical studies of MSCs for DRE. Medline, Ovid EMBASE, Scopus, and the Cochrane Databases were electronically searched from their dates of inception to November 2021 using the following keywords: (("mesenchymal") AND ("stem cell")) AND (("epilepsy") OR ("convulsion") OR ("seizures")). This review followed the PRISMA guidelines. The initial query identified 488 studies representing 323 unique manuscripts. After application of selection criteria, 15 studies were included in this systematic review; 11 were preclinical studies and 4 were clinical studies. All preclinical studies were performed in rodents and all clinical studies were phase 1 trials. Thus far, therapy with MSCs appears to be safe for use in humans, as no severe adverse events directly related to the therapy were reported. Furthermore, MSC therapy appears to provide a statistically significant clinical benefit by reducing the seizure burden of patients, reducing the electrophysiological biomarkers of epilepsy, and improving their comorbidities, such as depression and anxiety. Additionally, animal studies reveal that the therapy exerts its effect by reducing aberrant mossy fiber sprouting (reduce excitatory pathways) and increasing GABAergic interneurons (increase inhibitory pathways). Both preclinical and clinical studies have shown MSC therapy to be safe and preliminary effective, thus warranting further studies to investigate its therapeutic potential.

Abstract LBA034: Necrostatin-1 Protects Ferroptosis by xCT Induction in a RIPK1- and IDO-independent manner

Ferroptosis is caused by the iron-mediated accumulation of lipid peroxidation, which is distinct from apoptosis and necroptosis. Necrostatin-1 inhibits receptor-interacting ser-ine/threonine-protein kinase 1 (RIPK1) to initiate necroptosis; it also inhibits indoleamine 2,3-dioxygenase (IDO) to regulate tumor immunity. However, few studies have examined the off-target effect of necrostatin-1 on the ferroptosis pathway. The present study examined wheth-er necrostatin-1 could interrupt ferroptosis induced by system xc- inhibitors (sulfasalazine and erastin) and a glutathione peroxidase 4 inhibitor (RSL3) in Huh7 and SK-HEP-1 cells. Necrostatin-1 completely prevented decreases in cell viability induced by sulfasalazine and erastin; it partially blunted decreases in cell viability induced by RSL3. Necrostatin-1, ferrostatin-1, and deferoxamine repressed sulfasalazine-provoked membrane permeabilization, as detected by 7-aminoactinomycin D staining and lipid peroxidation measured using a C11-BODIPY probe. However, other RIPK1 inhibitors (necrostatin-1s and GSK2982772) and an IDO inhibitor (1-methyl-D-tryptophan) did not recover the decrease in cell viability induced by sulfasalazine. Necrostatin-1 potentiated sulfasalazine-induced expression of xCT, a catalytic subunit of system xc- in these cells. These results demonstrated that necrostatin-1 blocked fer-roptosis through a mechanism independent from RIPK1 and IDO inhibition in Huh7 and SK-HEP-1 cells, indicating that its antioxidant activity should be considered when using necrostatin-1 as a RIPK1 inhibitor.

Citation Format: Md Abdullah, Hanna Yuk, Do Hyung Kim, Haeseung Lee, Seung Jin Lee. Necrostatin-1 Protects Ferroptosis by xCT Induction in a RIPK1- and IDO-independent manner [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr LBA034.

Investigating the Feasibility of In Vivo Perfusion Imaging Methods for Spinal Cord Using Hyperpolarized [13C]t-Butanol and [13C,15N2]Urea

PURPOSE

This study examined the feasibility of using two novel agents, hyperpolarized [¹³C]t-butanol and [¹³C,¹⁵N₂]urea, for assessing in vivo perfusion of the intact spinal cord in rodents. Due to their distinct permeabilities to blood brain barrier (BBB), we hypothesized that [¹³C]t-butanol and [¹³C,¹⁵N₂]urea exhibit unique ¹³C signal characteristics in the spinal cord.

PROCEDURES

Dynamic ¹³C t-butanol MRI data were acquired from healthy Long-Evans rats using a symmetric, ramp-sampled, partial-Fourier ¹³C echo-planar imaging sequence after the injection of hyperpolarized [¹³C]t-butanol solution. In subsequent scans, dynamic ¹³C urea MRI data were acquired after the injection of hyperpolarized [¹³C,¹⁵N₂]urea. The SNRs of t-butanol and urea were calculated for regions corresponding to spine, supratentorial brain, and blood vessels and plotted over time. Mean peak SNR and AUC were calculated from the dynamic plots for each region and compared between t-butanol and urea.

RESULTS

In spine and supratentorial brain, the mean peak SNR and AUC of t-butanol were significantly higher than those of urea (p < 0.05). In contrast, urea was predominantly contained within vasculature and exhibited significantly higher levels of mean peak SNR and AUC compared to t-butanol in blood vessels (p < 0.05).

CONCLUSION

This study has demonstrated the feasibility of using hyperpolarized [¹³C]t-butanol and [¹³C,¹⁵N₂]urea for assessing in vivo perfusion in cervical spinal cord. Due to differences in blood-brain barrier permeability, t-butanol rapidly crossed the blood-brain barrier and diffused into spine and brain tissue, while urea predominantly remained in vasculature. The results from this study suggest that this technique may provide unique non-invasive imaging tracers that are able to directly monitor hemodynamic processes in the normal and injured spinal cord.

Extracellular Concentration of L-Cystine Determines the Sensitivity to System xc - Inhibitors

Targeting the cystine/glutamate exchange transporter, system x_c^-, is a promising anticancer strategy that induces ferroptosis, which is a distinct form of cell death mediated by iron-dependent lipid peroxidation. The concentration of L-cystine in culture medium is higher than the physiological level. This study was aimed to evaluate the effects of L-cystine concentration on the efficacy of ferroptosis inducers in hepatocellular carcinoma cells. This study showed that treatment with sulfasalazine or erastin, a system x_c^- inhibitor, decreased the viability of Huh6 and Huh7 cells in a dose-dependent manner, and the degree of growth inhibition was greater in medium containing a physiological L-cystine concentration of 83 µM than in commercial medium with a concentration of 200 µM L-cystine. However, RSL3, a glutathione peroxidase 4 inhibitor, decreased cell viability to a similar extent in media containing both L-cystine concentrations. Sulfasalazine and erastin significantly increased the percentages of propidium iodide-positive cells in media with 83 µM L-cystine, but not in media with 200 µM L-cystine. Sulfasalazine- or erastin-induced accumulation of lipid peroxidation as monitored by C11-BODIPY probe was higher in media with 83 µM L-cystine than in media with 200 µM L-cystine. In contrast, the changes in the percentages of propidium iodide-positive cells and lipid peroxidation by RSL3 were similar in both media. These results showed that sulfasalazine and erastin, but not RSL3, were efficacious under conditions of physiological L-cystine concentration, suggesting that medium conditions would be crucial for the design of a bioassay for system x_c^- inhibitors.

Experimental Demonstration of a Stacked Hybrid Optoacoustic-Piezoelectric Transducer for Localized Heating and Enhanced Cavitation

Laser-generated focused ultrasound (LGFU) is an emerging modality for cavitation-based therapy. However, focal pressure amplitudes by LGFU alone to achieve pulsed cavitation are often lacking as a treatment depth increases. This requires a higher pressure from a transmitter surface and more laser energies that even approach to a damage threshold of transmitter. To mitigate the requirement for LGFU-induced cavitation, we propose LGFU configurations with a locally heated focal zone using an additional high-intensity focused ultrasound (HIFU) transmitter. After confirming heat-induced cavitation enhancement using two separate transmitters, we then developed a stacked hybrid optoacoustic-piezoelectric transmitter, which is a unique configuration made by coating an optoacoustic layer directly onto a piezoelectric substrate. This shared curvature design has great practical advantage without requiring the complex alignment of two focal zones. Moreover, this enabled the amplification of cavitation bubble density by 18.5-fold compared to the LGFU operation alone. Finally, the feasibility of tissue fragmentation was confirmed through a tissue-mimicking gel, using the combination of LGFU and HIFU (not via a stacked structure). We expect that the stacked transmitter can be effectively used for stronger and faster tissue fragmentation than the LGFU transmitter alone.

[Direct MR Arthrography of the Hip: Diagnosis and Pitfalls of Acetabular Labral Lesions]

Tearing of the acetabular labrum is a common cause of chronic hip pain. MR arthrography (MRA) of the hip is the imaging procedure of choice for the evaluation of acetabular labrum. Familiarity with the various imaging findings of MRA of the hip allows recognition of normal variants and differentiation from true pathologic conditions. This article comprehensively reviews the technical aspects and interpretation of MRA of the hip. The appearances of normal and abnormal labra in MRA are discussed. Potential pitfalls in labral tear interpretation, such as sulci around the hip, normal variants of the labrum and plicae, and osseocartilaginous and soft tissue lesions identified on MRA of the hip are also described.

Hematologic Emergencies in the Postoperative Neurointensive Care Unit Setting: Illustrative Case Series and Differential Diagnosis

OBJECTIVES

Investigating the development of acute thrombocytopenia, differential etiologies, and potentially the rare manifestation of disseminated intravascular coagulation after brain tumor resection of primary and secondary malignancies.

MATERIALS AND METHODS

We performed a retrospective review of a case series of post-operative neurosurgical patients which developed thrombocytopenia. We applied National Library of Medicine search engine methodology using the terms disseminated intravascular coagulation and brain tumors.

RESULTS

We report clinical, radiographic, and laboratory data of four Neurointensive care unit patients that developed thrombocytopenia, three with disseminated intravascular coagulation after craniotomy, and one with heparin-induced thrombocytopenia masquerading as low grade disseminated intravascular coagulation. All four patients presented with cranial lesions and underwent neurosurgical resection. Underlying disorders included: high grade glioma, stage IV lung cancer with metastases, and meningioma. One patient survived and was able to recover after several days of hospitalization, while another patient was discharged to hospice. Search results illustrated that disseminated intravascular coagulation in the presence of glioblastoma multiforme is rare (only four patients) and may be due to a release of coagulation factors like tissue plasminogen activator, treated with antifibrinolytic agents. Searching the terms disseminated intravascular coagulation and brain tumors in the National Library of Medicine search engine yielded 116 results; eight were relevant to our study.

CONCLUSIONS

Correlation of thrombocytopenia after neurosurgery for glioblastoma multiforme and disseminated intravascular coagulation is rare. It is extremely challenging to manage these patients with concomitant deep vein thrombosis/pulmonary embolism and intracranial bleeding. Heparin-induced thrombocytopenia is common yet possesses a different hematological coagulation profile and has more pharmacologic options. Neurointensive care unit teams should recognize intraoperative and post-operative disseminated intravascular coagulation cases, and heparin-induced thrombocytopenia in the differential of post-operative thrombocytopenia with specific pharmacologic interventions.

Clinical risk factors and pattern of initial fungal contamination in endoscopic biopsy-derived gastrointestinal cancer organoid culture

BACKGROUND/AIMS

Because gastrointestinal tract is not sterile, primary culture has contamination risk despite of massive washing with antimicrobial media. Microbial contamination can play a key role in initial failure during biopsy-derived primary tumor culture.

METHODS

Tumor tissue was acquired from esophageal and gastric tumors using endoscopic biopsy. Three-dimensional cultures were performed, and separated spheroids were cultured in media for 7 to 10 days and then transferred to Matrigel (Corning Inc.). We investigated risk factors and patterns of initial fungal contamination.

RESULTS

Initial tumor contamination was observed in 23% (7/30) of esophageal cancer and 20% (3/15) of gastric cancer samples. Two cases of bacterial contamination occurred during the establishment of culture protocol. Moderate to thick whitish plaques (p < 0.001) and food retention in lumen (p < 0.001) were risk factors for initial fungal contamination. After exclusion of high risk patients for contamination, no fungal contamination occurred in primary organoid cultures. Fungal contamination was usually detected within 3 days after tumor preparation. However, unusual fungal contamination (GC11 and EC29) was recognized after several passages. Growing spherical shapes resembled cancer organoids. Although they rapidly proliferated and multiple daughter spheroids appeared, the media were translucent. After several passages, yeasts and pseudohyphae were detected on the edges of the solid spherical structures and media.

CONCLUSION

Moderate to thick whitish plaques and food retention are clinical risk factors for initial fungal contamination during biopsy-derived cancer organoid culture. Most initial fungal contamination was detected within 3 days, but it could be unusually recognized after several passages.

Care and Management of Voice Change for Thyroid Surgery: Korean Society of Laryngology, Phoniatrics and Logopedics Clinical Practice Guideline

Voice change is a common complaint after thyroid surgery and has significant impacts on quality of life. The Korean Society of Laryngology, Phoniatrics, and Logopedics set up a task force team to establish guideline recommendations on education, care, and management related to thyroid surgery. The guideline recommendations include preoperative voice education, management of anticipated voice change during surgery, and comprehensive voice care after thyroid surgery, including in-depth information and up-to-date knowledge based on validated literature. The committee constructed 14 key questions (KQ) in three categories: preoperative (KQ1-2), intraoperative (KQ 3-8), and postoperative (KQ 9-14) management and developed 18 evidence-based recommendations. The Delphi survey reached an agreement on each recommendation. Detailed evidence profiles are presented for each recommendation. The level of evidence for each recommendation is classified into high, moderate, and low-quality. The recommendation's strengths are adjusted to consider the level of evidence resulting in the recommendation and are divided into strong and weak. The guidelines are primarily targeted toward physicians who treat thyroid surgery patients and speech-language pathologists participating in patient care. These guidelines will also help primary care physicians, nurses, healthcare policymakers, and patients improve their understanding of voice changes and voice care after thyroid surgery.

Electrophilic and Drug-Induced Stimulation of NOTCH3 N-terminal Fragment Oligomerization in Cerebrovascular Pathology

Small vessel disease is a prevalent age-related condition linked to increased risk of dementia and stroke. We investigate the most commonly inherited form, CADASIL, caused by cysteine-involving mutations in NOTCH3. Recent studies highlight accumulation of NOTCH3 N-terminal fragmentation product (NTF) in disease. In vitro, NTF is capable of both spontaneous and catecholamine-enhanced cysteine-mediated oligomerization. Despite well-characterized genetic influence on CADASIL, environmental effects, including medication usage, on disease remain unclear. We studied effects of assorted electrophilic compounds and drugs on NTF oligomerization by SDS-PAGE and dynamic light scattering. We then examined direct proton pump inhibitor-NTF binding with antibodies designed against proton pump inhibitor-labeled proteins and mass spectrometry. Finally, we used monoclonal NTF antibodies with Proximity Ligation Assay to identify NTF oligomers in 3 CADASIL and 2 age-matched control brains. We identified enhancement of NTF oligomerization by two electrophilic cysteine-modifying compounds, N-ethylmaleimide and iodoacetamide, and an electrophilic compound capable of oxidizing cysteines, ferric chloride. Electrophilic clinical drugs (fenoldopam, omeprazole, tenatoprazole, lansoprazole, and rabeprazole) also promoted oligomerization, and we identified direct omeprazole-NTF and tenatoprazole-NTF complexes. Additionally, we provide novel evidence of NTF multimers in human CADASIL brains. A broad array of electrophilic chemicals, including clinically relevant drugs, influences oligomerization of a pathological CADASIL protein, providing mechanistic insight into disease protein oligomerization. We posit that environmental influences, which may include usage of electrophilic drugs, may affect CADASIL presentations.

When Azoles Cannot Be Used: The Clinical Effectiveness of Intermittent Liposomal Amphotericin Prophylaxis in Hematology Patients

Background

Patients unable to take azoles are a neglected group lacking a standardized approach to antifungal prophylaxis. We evaluated the effectiveness and safety of intermittent liposomal amphotericin B (L-AMB) prophylaxis in a heterogenous group of hematology patients.

Methods

A retrospective cohort of all hematology patients who received a course of intravenous L-AMB, defined as 1 mg/kg thrice weekly from July 1, 2013 to June 30, 2018, were identified from pharmacy records. Outcomes included breakthrough-invasive fungal disease (BIFD), reasons for premature discontinuation, and acute kidney injury.

Results

There were 198 patients who received 273 courses of L-AMB prophylaxis. Using a conservative definition, the BIFD rate was 9.6% (n = 19 of 198) occurring either during L-AMB prophylaxis or up to 7 days from cessation in patients who received a course. Probable/proven BIFD occurred in 13 patients (6.6%, 13 of 198), including molds in 54% (n = 7) and non-albicans Candidemia in 46% (n = 6). Cumulative incidence of BIFD was highest in patients with acute myeloid leukemia (6.8%) followed by acute lymphoblastic leukemia (2.7%) and allogeneic stem cell transplantation (2.5%). The most common indication for L-AMB was chemotherapy, or anticancer drug-azole interactions (75% of courses) dominated by vincristine, or acute myeloid leukemia clinical trials, followed by gut absorption concerns (13%) and liver function abnormalities (8.8%). Acute kidney injury, using a modified international definition, complicated 27% of courses but was not clinically significant, accounting for only 3.3% (9 of 273) of discontinuations.

Conclusions

Our findings demonstrate a high rate of BIFD among patients receiving L-AMB prophylaxis. Pragmatic trials will help researchers find the optimal regimen of L-AMB prophylaxis for the many clinical scenarios in which azoles are unsuitable, especially as targeted anticancer drugs increase in use.

Paratrimerins J-Y, Dimeric Coumarins Isolated from the Stems of Paramignya trimera

Paratrimerins J-Y (1-13 and 16-18), new dimeric coumarins, were obtained from the EtOH(aq) extract of the stems of Paramignya trimera (Rutaceae) utilizing LC/MS guided isolation. The structures of the dimeric coumarins were elucidated based on 1D/2D NMR spectroscopic and HR-ESIMS data analyses. The absolute configurations of paratrimerins J-Y along with those of two known dimers paratrimerins A (14) and B (15) were established on the basis of the experimental and simulated ECD data. In addition, the absolute configurations of the sugar units of paratrimerins A, B, and J-V (1-15) were confirmed by LC/MS analysis on l-cysteine methyl ester and phenyl isothiocyanate derivatives. The variety of the absolute configurations of the dimeric diastereomers 1-15 highlighted a diversity in stereochemical outcomes following a Diels-Alder biosynthesis in P. trimera. With regard to P. trimera being a recently emerging medicinal resource for liver cancer, the dimers 1-18 were evaluated for cytotoxicity against a wide panel of human cancer cell lines. Paratrimerin W (16) was cytotoxic toward Huh7 hepatocellular carcinoma, HT1080 fibrosarcoma, and HT29 colorectal cancer cells with IC₅₀ values of 14.9, 18.4, and 22.5 μM, respectively.

Results on Low-Mass Weakly Interacting Massive Particles from an 11 kg d Target Exposure of DAMIC at SNOLAB

We present constraints on the existence of weakly interacting massive particles (WIMPs) from an 11 kg d target exposure of the DAMIC experiment at the SNOLAB underground laboratory. The observed energy spectrum and spatial distribution of ionization events with electron-equivalent energies >200  eV_{ee} in the DAMIC CCDs are consistent with backgrounds from natural radioactivity. An excess of ionization events is observed above the analysis threshold of 50  eV_{ee}. While the origin of this low-energy excess requires further investigation, our data exclude spin-independent WIMP-nucleon scattering cross sections σ_{χ-n} as low as 3×10^{-41}  cm^{2} for WIMPs with masses m_{χ} from 7 to 10  GeV c^{-2}. These results are the strongest constraints from a silicon target on the existence of WIMPs with m_{χ}<9  GeV c^{-2} and are directly relevant to any dark matter interpretation of the excess of nuclear-recoil events observed by the CDMS silicon experiment in 2013.

Factors influencing long-term treatment response to botulinum toxin injection for spasmodic dysphonia

OBJECTIVE

The purpose of this study was to evaluate the outcomes of long-term botulinum toxin type A (BoNTA) treatment for adductor spasmodic dysphonia (AdSD) and to determine the factors predictive of treatment response by investigating dose stability and average intervals.

DESIGN

Retrospective cohort study.

SETTING

Academic tertiary medical centre.

EXPOSURES

A total of 470 patients with adductor spasmodic dysphonia, who received electromyography-guided BoNTA injections over 12 years, were retrospectively enrolled in this study.

MAIN OUTCOMES AND MEASURES

The patients' demographic data, baseline voice dynamics and treatment profiles (dose, frequency and intervals) were evaluated. Factors correlating with the dose adjustment ratio (number of increasing dosing/total number of BoNTA toxin injections) and changes in intervals between injections were statistically analysed.

RESULTS

A total of 122 patients, who received ≥ 4 injections and whose average treatment interval was < 240 days, were finally evaluated. Of them, 115 (94.3%) were female and seven (5.7%) were male, and the mean age at initial treatment was 34.89 ± 13.07 and 41.14 ± 12.71 years, respectively. On average, patients received 18.00 ± 13.33 injections (1.67 ± 0.60 U/injection) to alternating unilateral vocal folds. The treatment period was 65.07 ± 43.28 months and the mean interval between injections was 4.16 ± 1.28 months. The mean dose adjustment ratio among patients who received ≥ 4 injections was 0.15 ± 0.13, and dose changes occurred 4.36 times/patient. The patients' age and gender significantly affected the treatment response, where younger or female patients showed greater dosing variability and shorter intervals between injections. However, the baseline voice dynamics (voice handicap index, fundamental frequency, jitter, shimmer, noise-to-harmonic ratio, maximum phonation time and degree of voice breaks) did not predict the dose adjustment ratio or interval changes. In addition, patients with fluctuating doses showed lower age and higher VHI subscale scores, and patients with short-treatment interval (< 100 days) showed higher SDF0.

CONCLUSIONS

Almost all patients received stable low doses of BoNTA over time, irrespective of the baseline results. Patients' age, gender and VHI scores were correlated with poor treatment responses, such as frequent dose changes and shorter intervals between injections.