Infinity: A Prospective Trial for Safety and Accuracy of Navigated Posterior Cervical and Thoracic Instrumentation in long-segment Fusions.

STUDY DESIGN: Unblinded single-arm prospective clinical trial. OBJECTIVE: Evaluate safety and accuracy of navigation for placement of posterior cervicothoracic instrumentation. SUMMARY OF BACKGROUND DATA: Computer assisted stereotactic navigation for placement of spinal instrumentation has been widely studied and implemented in the thoracic and lumbar spine. However less literature exists regarding the use of computer assisted navigation for posterior cervical instrumentation, particularly with lateral mass fixation. Here we present the first prospective study of navigated cervical lateral mass screw placement for cervicothoracic fusion. METHODS: Patients who met indications for posterior cervical fusion were screened, consented, and enrolled preoperatively for instrumentation with Medtronic Infinity Occipital-Cervical-Thoracic implants, with use of intraoperative O-arm and stereotactic Stealth navigation. Postoperative CTs of the instrumented levels were obtained during the same hospital admission. Primary outcome of the trial was safety. Secondary outcomes were screw accuracy assessed by Gertzbein-Robbins grade, neurologic exams, and patient reported outcomes on the PROMIS 29 questionnaire. RESULTS: A total of 50 patients underwent surgery, and 557 screws were placed. There were no adverse events related to the use of navigation or screw malposition. Gertzbein-Robbins grade A or B placement comprised 95% of navigated screws. There was a decrease in positive Hoffmann sign rate postoperatively, and sensory and motor exams remained stable. There was improvement in patient reported pain and sleep domains. CONCLUSIONS: Navigation for cervicothoracic instrumentation is safe overall and leads to high rates of accurately placed screws. Longer term follow up could provide more insight to whether the use of this technology results in durable improvement in spinal alignment parameters and patient reported outcomes. LEVEL OF EVIDENCE: 3.

Tumor-related epilepsy in high-grade glioma: a large series survival analysis.

PURPOSE: Seizures are a common clinical occurrence in high-grade glioma (HGG). While many studies have explored seizure incidence and prevalence in HGG, limited studies have examined the prognostic effect of seizures occurring in the post-diagnosis setting. This study aims to assess the impact of seizure presentation on HGG survival outcomes. METHODS: Single-center retrospective review identified 950 patients with histologically-confirmed high-grade glioma. Seizure presentation was determined by clinical history and classified as early onset (occurring within 30 days of HGG presentation) or late onset (first seizure occurring after beginning HGG treatment). The primary outcome, hazard ratios for overall survival and progression-free survival, was assessed with multivariable Cox proportional-hazards models. IDH1 mutation status (assessed through immunohistochemistry) was only consistently available beginning in 2015; subgroup analyses were performed in the subset of patients with known IDH1 status. RESULTS: Epileptic activity before (HR = 0.81, 95% CI = 0.68-0.96, P = 0.017) or after (HR = 0.74, 95% CI = 0.60-0.91, P = 0.005) HGG diagnosis associated with improved overall survival. Additionally, late seizure onset significantly associated with lower odds of achieving partial (OR = 0.25, 95% CI = 0.12-0.53, P = < 0.001) or complete (OR = 0.30, 95% CI = 0.18-0.50, P < 0.001) seizure control than patients with early seizure onset. CONCLUSIONS: Clinical seizures both at the time of diagnosis and later during the HGG treatment course are associated with improved overall survival. This association potentially persists for both IDH1-wildtype and IDH1-mutant patients, but further study is required.

A Comparative Assessment of Outcomes Following Mandibular Distraction Osteogenesis and Tongue-Lip Adhesion in Pierre Robin Sequence.

The purpose of this study was to assess long-term outcomes of tongue-lip adhesion (TLA) and mandibular distraction osteogenesis (MDO) to resolve upper airway obstruction in patients with Robin sequence (RS). A retrospective cohort study was performed of subjects presenting to a tertiary care pediatric center who underwent either primary MDO or TLA for the treatment of RS between 2004 and 2020. N=59 subjects met inclusion criteria (n=34 MDO, n=25 TLA), and there were no significant differences in preoperative patient characteristics other than age at surgery (MDO 31 d vs. TLA 17 d, P=0.049). Preoperative apnea-hypopnea index (AHI) was similar between cohorts (33.9 and 46.7, P=0.38). Subjects who underwent MDO demonstrated improved AHI on initial postoperative polysomnogram performed at 2 weeks (3.4 vs. 11.6, P=0.014), however AHI at the second postoperative timepoint (270 vs. 142 d, P=0.007) was no different between cohorts (2.8 vs. 2.6, P=0.89). No subject in either group required enteral nutrition or supplemental oxygen at last follow-up. In subjects undergoing MDO, 14.7% demonstrated temporary asymmetric marginal mandibular nerve dysfunction. Forty-seven percent of MDO patients had injury to first primary molars. MDO and TLA both ultimately achieved similar long-term resolution of upper airway obstruction and associated feeding difficulties in patients with Robin sequence. MDO offered a more immediate airway improvement, but the procedure carried a potential risk of neurosensory and dental injury when compared with TLA.

Microbial etiology of vertebral osteomyelitis/discitis amid the opioid epidemic.

OBJECTIVE: The primary goal of this study was to establish the current microbial trends in vertebral osteomyelitis/discitis (VOD) amid the opioid epidemic and to determine if intravenous drug use (IVDU) predisposes one to a unique microbial profile of infection. METHODS: The authors performed a retrospective cohort study consisting of 1175 adult patients diagnosed with VOD between 2011 and 2022 at a single quaternary center. Data were acquired through retrospective chart review, with pertinent demographic and clinical information collected. RESULTS: Staphylococcus aureus was the most cultured organism in both the IVDU and non-IVDU groups at 56.1% and 40.7%, respectively. In the IVDU cohort, Serratia marcescens was the next most prevalently cultured organism at 13.9%. CONCLUSIONS: The present study demonstrates that in the IVDU population S. marcescens is an organism of high concern. The potential for Serratia spp. infection should be accounted for when selecting empirical antimicrobial therapy in VOD patients.

Huntingtin contains an ubiquitin-binding domain and regulates lysosomal targeting of mitochondrial and RNA-binding proteins.

Understanding the normal function of the Huntingtin (HTT) protein is of significance in the design and implementation of therapeutic strategies for Huntington's disease (HD). Expansion of the CAG repeat in the HTT gene, encoding an expanded polyglutamine (polyQ) repeat within the HTT protein, causes HD and may compromise HTT's normal activity contributing to HD pathology. Here, we investigated the previously defined role of HTT in autophagy specifically through studying HTT's association with ubiquitin. We find that HTT interacts directly with ubiquitin in vitro. Tandem affinity purification was used to identify ubiquitinated and ubiquitin-associated proteins that copurify with a HTT N-terminal fragment under basal conditions. Copurification is enhanced by HTT polyQ expansion and reduced by mimicking HTT serine 421 phosphorylation. The identified HTT-interacting proteins include RNA-binding proteins (RBPs) involved in mRNA translation, proteins enriched in stress granules, the nuclear proteome, the defective ribosomal products (DRiPs) proteome and the brain-derived autophagosomal proteome. To determine whether the proteins interacting with HTT are autophagic targets, HTT knockout (KO) cells and immunoprecipitation of lysosomes were used to investigate autophagy in the absence of HTT. HTT KO was associated with reduced abundance of mitochondrial proteins in the lysosome, indicating a potential compromise in basal mitophagy, and increased lysosomal abundance of RBPs which may result from compensatory up-regulation of starvation-induced macroautophagy. We suggest HTT is critical for appropriate basal clearance of mitochondrial proteins and RBPs, hence reduced HTT proteostatic function with mutation may contribute to the neuropathology of HD.

2-Substituted (N)-Methanocarba A3 Adenosine Receptor Agonists: In Silico, In Vitro, and In Vivo Characterization.

2-Arylethynyl (N)-methanocarba adenosine 5'-methylamides are selective A3 adenosine receptor (AR) agonists containing a preestablished receptor-preferred pseudoribose conformation. Here, we compare analogues having bulky 2-substitution, either containing or lacking an ethynyl spacer between adenine and a cyclic group. 2-Aryl compounds 9-11, 13, 14, 19, 22, 23, 27, 29, 31, and 34, lacking a spacer, had human (h) A3AR K i values of 2-30 nM, and others displayed lower affinity. Mouse (m) A3AR affinity varied, with 2-arylethynyl having a higher affinity than 2-aryl analogues (7, 8 > 3c, 3d > 3b). However, 2-aryl-4'-truncated derivatives had greatly reduced hA3AR affinity, even containing affinity-enhancing N 6-dopamine-derived substituents. Molecular modeling, including molecular dynamics simulation, predicted stable poses in the canonical A3AR agonist binding site, but 2-aryl (ECL2 interactions) and 2-arylethynyl (TM2 interactions) substituents have different conformations and environments. In a hA3AR miniGαi recruitment assay, 31 (MRS8062) was (slightly) more potent compared to a ß-arrestin2 recruitment assay, both in engineered HEK293T cells, and its maximal efficacy (E max) was much higher (165%) than reference agonist NECA's. Thus, in the 2-aryl series, A3AR affinity and selectivity were variable and generally reduced compared to the 2-arylethynyl series, with a greater dependence on the specific aryl group present. Selected compounds were studied in vivo in an ischemic model of peripheral artery disease (PAD). Rigidified 2-arylethynyl analogues 3a-3c were protective in this model of skeletal muscle ischemia-reperfusion injury/claudication, as previously shown only for moderately A3AR-selective ribosides or (N)-methanocarba derivatives. Thus, we have expanded the A3AR agonist SAR for (N)-methanocarba adenosines.

Mechanisms of Photoredox Catalysis Featuring Nickel-Bipyridine Complexes.

Metallaphotoredox catalysis can unlock useful pathways for transforming organic reactants into desirable products, largely due to the conversion of photon energy into chemical potential to drive redox and bond transformation processes. Despite the importance of these processes for cross-coupling reactions and other transformations, their mechanistic details are only superficially understood. In this review, we have provided a detailed summary of various photoredox mechanisms that have been proposed to date for Ni-bipyridine (bpy) complexes, focusing separately on photosensitized and direct excitation reaction processes. By highlighting multiple bond transformation pathways and key findings, we depict how photoredox reaction mechanisms, which ultimately define substrate scope, are themselves defined by the ground- and excited-state geometric and electronic structures of key Ni-based intermediates. We further identify knowledge gaps to motivate future mechanistic studies and the development of synergistic research approaches spanning the physical, organic, and inorganic chemistry communities.

Fetal lower urinary tract obstruction: international Delphi consensus on management and core outcomes set.

OBJECTIVE: To reach a Delphi-generated international expert consensus on the diagnosis, prognostic, management, and core outcome set (COS) of fetal Lower Urinary Tract Obstruction (LUTO). METHODS: A three-round Delphi procedure was conducted among an international panel of LUTO experts. The panel was provided with a list of literature review-generated parameters for the diagnosis, prognostic, management, and outcomes. A parallel procedure was conducted along with patient groups during the development of COS. RESULTS: A total of 160 experts were approached, of whom 99 completed the first round and 80 (80/99, 80.8%) completed all three rounds. In the first trimester, an objective measurement of longitudinal bladder diameter (with ≥7 mm being abnormal) should be used to suspect LUTO. In the second trimester, imaging parameters of LUTO could include: a) an enlarged bladder, b) a keyhole sign, c) bladder wall thickening, d) bilateral hydro (uretero) nephrosis, and e) male sex. There was a lack of consensus on the current prognostic scoring literature. However, experts agreed on the value of amniotic fluid volume (< 24 weeks) to predict survival and that the value of fetal intervention is to improve neonatal survival. While experts endorsed the role of sonographic parameters of renal dysplasia, at least one vesicocentesis, and urine biochemistry for prognosis and counseling, these items did not reach a consensus for determining fetal intervention candidacy. On the other hand, imaging parameters suggestive of LUTO, absence of life-limiting structural or genetic anomalies, gestational age of ≥16 weeks, and oligohydramnios defined as deepest vertical pocket (DVP) <2 cm should be used as candidacy criteria for fetal intervention based on experts' consensus. If a bladder refill was evaluated, it should be assessed subjectively. Vesicoamniotic shunt should be the first line of fetal intervention. In the presence of suspected fetal renal failure, serial amnioinfusion should only be offered as an experimental procedure under research protocols. The core outcome set for future studies was agreed upon. CONCLUSION: International consensus on the diagnosis, prognosis, and management of fetal LUTO, as well as the Core Outcome Set, should inform clinical care and research to optimize perinatal outcomes. This article is protected by copyright. All rights reserved.

Enhanced recovery after fetal spina bifida surgery: what is our global practice?

OBJECTIVE: Prenatal spina bifida closure results in improved outcomes for the child compared to postnatal surgery but is associated with significant maternal morbidity. Optimization of the perioperative care for women who underwent fetal spina bifida surgery could improve maternal and pregnancy outcomes. Enhanced Recovery After Surgery (ERAS) protocols are multimodal, evidence-based care plans that have been adopted for multiple surgical procedures to promote faster and better patient recovery and shorter hospitalization. This study aims to explore if fetal centers have implemented ERAS principles in this setting. Furthermore, we provide recommendations for the perioperative management of patients undergoing fetal spina bifida surgery. METHODS: Fifty-three fetal therapy centers offering prenatal surgery for open spina bifida were identified and invited to complete a digital questionnaire covering their pre-, intra- and postoperative management. An overall score was calculated per center based on the center's compliance with 20 key ERAS principles, extrapolated from ERAS guidelines for cesarean section, gynecologic oncology and colorectal surgery. Each item was scored 1 or 0 when the center did or did not comply with each principle, with a maximum score of 20. RESULTS: The questionnaire was completed by 46 centers in 17 countries (response rate 87%). Twenty-two centers (48%) exclusively perform open fetal surgery (laparotomy and hysterotomy), whereas 14 (30%) offer both open and fetoscopic procedures and 10 (22%) use fetoscopy only. The perioperative management of patients undergoing fetoscopic and open surgery was highly similar. The median ERAS score was 12 (mean 12.5, SD 2.4, range 8-17). Center compliance was the highest for the use of regional anesthesia (98%), avoidance of bowel preparation (96%), and thromboprophylaxis (96%), while the lowest compliance was achieved for preoperative carbohydrate loading (15%), postoperative nausea and vomiting prevention (33%), avoidance of overnight fasting (33%) and a 2-hour fasting period for clear fluids (20%). ERAS scores were similar in centers with a short (2-5 days), medium (6-10 days) and long (≥11 days) hospital stay (12.8 ± 2.4, 12.1 ± 2.0, and 10.3 ± 3.2, respectively, p=0.15). Furthermore, there was no significant association between ERAS score and surgical technique or center volume. CONCLUSION: The perioperative management of fetal spina bifida surgery is highly variable across fetal therapy centers worldwide. Standardizing protocols according to ERAS principles may improve patient recovery, reduce maternal morbidity, and shorten hospital stay after fetal spina bifida surgery. This article is protected by copyright. All rights reserved.

Utility of Large Language Models to Produce a Patient-Friendly Summary From Oncology Consultations.

LLMs can rewrite oncologic notes as plain-language summaries, which may aid communication and comprehension.

ALOX15B controls macrophage cholesterol homeostasis via lipid peroxidation, ERK1/2 and SREBP2.

Macrophage cholesterol homeostasis is crucial for health and disease and has been linked to the lipid-peroxidizing enzyme arachidonate 15-lipoxygenase type B (ALOX15B), albeit molecular mechanisms remain obscure. We performed global transcriptome and immunofluorescence analysis in ALOX15B-silenced primary human macrophages and observed a reduction of nuclear sterol regulatory element-binding protein (SREBP) 2, the master transcription factor of cellular cholesterol biosynthesis. Consequently, SREBP2-target gene expression was reduced as were the sterol biosynthetic intermediates desmosterol and lathosterol as well as 25- and 27-hydroxycholesterol. Mechanistically, suppression of ALOX15B reduced lipid peroxidation in primary human macrophages and thereby attenuated activation of mitogen-activated protein kinase ERK1/2, which lowered SREBP2 abundance and activity. Low nuclear SREBP2 rendered both, ALOX15B-silenced and ERK1/2-inhibited macrophages refractory to SREBP2 activation upon blocking the NPC intracellular cholesterol transporter 1. These studies suggest a regulatory mechanism controlling macrophage cholesterol homeostasis based on ALOX15B-mediated lipid peroxidation and concomitant ERK1/2 activation.

Childhood opportunity and appropriate use of child safety restraints in motor vehicle collisions.

Objectives: Safety restraints reduce injuries from motor vehicle collisions (MVCs) but are often improperly applied or not used. The Childhood Opportunity Index (COI) reflects social determinants of health and its study in pediatric trauma is limited. We hypothesized that MVC patients from low-opportunity neighborhoods are less likely to be appropriately restrained. Methods: A retrospective cross-sectional study was performed on children/adolescents ≤18 years old in MVCs between January 1, 2011 and December 31, 2021. Patients were identified from the Children's Hospital Los Angeles trauma registry. The outcome was safety restraint use (appropriately restrained, not appropriately restrained). COI levels by home zip codes were stratified as very low, low, moderate, high, and very high. Multivariable regression controlling for age identified factors associated with safety restraint use. Results: Of 337 patients, 73.9% were appropriately restrained and 26.1% were not appropriately restrained. Compared with appropriately restrained patients, more not appropriately restrained patients were from low-COI (26.1% vs 20.9%), high-COI (14.8% vs 10.8%) and very high-COI (10.2% vs 3.6%) neighborhoods. Multivariable analysis demonstrated no significant associations in appropriate restraint use and COI. There was a non-significant trend that children/adolescents from moderate-COI neighborhoods were more likely than those from very low-COI neighborhoods to be appropriately restrained (OR=1.82, 95% CI 0.78, 4.28). Conclusion: Injury prevention initiatives focused on safety restraints should target families of children from all neighborhood types. Level of evidence: III.

The Sensitivity of Limited-Sequence MRI in Identifying Pediatric Cervical Spine Injury: A Western Pediatric Surgery Research Consortium Multicenter Retrospective Cohort Study.

INTRODUCTION: Clinical clearance of a child's cervical spine after trauma is often challenging due to impaired mental status or an unreliable neurologic examination. Magnetic resonance imaging (MRI) is the gold standard for excluding ligamentous injury in children but is constrained by long image acquisition times and frequent need for anesthesia. Limited-sequence MRI (LSMRI) is used in evaluating the evolution of traumatic brain injury and may also be useful for cervical spine clearance while potentially avoiding the need for anesthesia. The purpose of this study was to assess the sensitivity and negative predictive value of LSMRI as compared to gold standard full-sequence MRI as a screening tool to rule out clinically significant ligamentous cervical spine injury. METHODS: We conducted a ten-center, five-year retrospective cohort study (2017-2021) of all children (0-18y) with a cervical spine MRI after blunt trauma. MRI images were re-reviewed by a study pediatric radiologist at each site to determine if the presence of an injury could be identified on limited sequences alone. Unstable cervical spine injury was determined by study neurosurgeon review at each site. RESULTS: We identified 2,663 children less than 18 years of age who underwent an MRI of the cervical spine with 1,008 injuries detected on full-sequence studies. The sensitivity and negative predictive value of LSMRI were both >99% for detecting any injury and 100% for detecting any unstable injury. Young children (age < 5 years) were more likely to be electively intubated or sedated for cervical spine MRI. CONCLUSION: LSMRI is reliably detects clinically significant ligamentous injury in children after blunt trauma. To decrease anesthesia use and minimize MRI time, trauma centers should develop LSMRI screening protocols for children without a reliable neurologic exam. LEVEL OF EVIDENCE: 2 (Diagnostic Tests or Criteria).

Changes in an enzyme ensemble during catalysis observed by high-resolution XFEL crystallography.

Enzymes populate ensembles of structures necessary for catalysis that are difficult to experimentally characterize. We use time-resolved mix-and-inject serial crystallography at an x-ray free electron laser to observe catalysis in a designed mutant isocyanide hydratase (ICH) enzyme that enhances sampling of important minor conformations. The active site exists in a mixture of conformations, and formation of the thioimidate intermediate selects for catalytically competent substates. The influence of cysteine ionization on the ICH ensemble is validated by determining structures of the enzyme at multiple pH values. Large molecular dynamics simulations in crystallo and time-resolved electron density maps show that Asp17 ionizes during catalysis and causes conformational changes that propagate across the dimer, permitting water to enter the active site for intermediate hydrolysis. ICH exhibits a tight coupling between ionization of active site residues and catalysis-activated protein motions, exemplifying a mechanism of electrostatic control of enzyme dynamics.

Prevalence and Outcomes of High versus Low Ratio Plasma to Red Blood Cell Resuscitation in a Multi-Institutional Cohort of Severely Injured Children.

BACKGROUND: The benefit of targeting high ratio fresh frozen plasma (FFP):red blood cell (RBC) transfusion in pediatric trauma resuscitation is unclear as existing studies are limited to patients who retrospectively met criteria for massive transfusion. The purpose of this study is to evaluate the use of high ratio FFP:RBC transfusion and the association with outcomes in children presenting in shock. METHODS: A post-hoc analysis of a 24-institution prospective observational study (4/2018-9/2019) of injured children <18 years with elevated age-adjusted shock index was performed. Patients transfused within 24 hours were stratified into cohorts of low (<1:2) or high (>1:2) ratio FFP:RBC. Nonparametric Kruskal-Wallis and chi-square were used to compare characteristics and mortality. Competing risks analysis was used to compare extended (≥75th percentile) ventilator, intensive care, and hospital days while accounting for early deaths. RESULTS: Of 135 children with median (IQR) age 10 (5,14) years and weight 40 (20,64) kg, 85 (63%) received low ratio transfusion and 50 (37%) high ratio despite similar activation of institutional massive transfusion protocols (MTP; low-38%, high-46%, p = .34). Most patients sustained blunt injuries (70%). Median injury severity score was greater in high ratio patients (low-25, high-33, p = .01); however, hospital mortality was similar (low-24%, high-20%, p = .65) as was the risk of extended ventilator, ICU, and hospital days (all p > .05). CONCLUSION: Despite increased injury severity, patients who received a high ratio of FFP:RBC had comparable rates of mortality. These data suggest high ratio FFP:RBC resuscitation is not associated with worst outcomes in children who present in shock. MTP activation was not associated with receipt of high ratio transfusion, suggesting variability in MTP between centers. LEVEL OF EVIDENCE: Prospective cohort study, Level II.

CT guided biopsy for osteodiscitis reduces cost of hospitalization in the landscape of increasing intravenous drug use: A single center retrospective analysis.

OBJECTIVE: Osteodiscitis has been demonstrated to show significant morbidity and mortality. Cultures and CT guided biopsy (CTB) are commonly used diagnosis of osteodiscitis. This study's purpose is to evaluate the cost burden of CTB and to evaluate how IVDU affects patient management in the setting of osteodiscitis. METHODS: Patients admitted for osteodiscitis from 2011-2021 were retrospectively reviewed and stratified into cohorts by CTB status. Additional cohorts were stratified by Intravenous Drug Use (IVDU). Patient demographics, total cost of hospitalization, length of hospitalization, time to biopsy, IVDU status, and other factors were recorded. T-Test, Chi-squared analysis, and ANOVA were used for statistical analysis. RESULTS: Total cost of hospitalization was recorded for 140 patients without CTB and 346 patients with CTB. Average cost of hospitalization for non-CTB was $227,317.86 compared to CTB at $119,799.20 (p < 0.001). Length of stay (LOS) was found to be 18.01 days for non-CTB and 14.07 days for CTB patients (0.00282). When stratified by days until biopsy, patients who had CTB sooner, had significantly reduced cost of hospitalization (p = 0.0003). Patients with IVDU history were significantly younger (p < 0.001) with lower BMI (p < 0.001) and a significantly different clinical profile. There was a significant difference in positive open biopsy when separated by IVDU status (p = 0.025). CONCLUSION: CTB was associated with significantly reduced cost of hospitalization and LOS compared to non-CTB. IVDU patients with osteodiscitis have significantly different clinical profiles than non-IVDU that may impact diagnosis and treatment. Further work is indicated to elucidate causes of these differences to provide high value care to patients with osteodiscitis.

Light Activation and Photophysics of a Structurally Constrained Nickel(II)-Bipyridine Aryl Halide Complex.

Transition-metal photoredox catalysis has transformed organic synthesis by harnessing light to construct complex molecules. Nickel(II)-bipyridine (bpy) aryl halide complexes are a significant class of cross-coupling catalysts that can be activated via direct light excitation. This study investigates the effects of molecular structure on the photophysics of these catalysts by considering an underexplored, structurally constrained Ni(II)-bpy aryl halide complex in which the aryl and bpy ligands are covalently tethered alongside traditional unconstrained complexes. Intriguingly, the tethered complex is photochemically stable but features a reversible Ni(II)-C(aryl) ⇄ [Ni(I)···C(aryl)•] equilibrium upon direct photoexcitation. When an electrophile is introduced during photoirradiation, we demonstrate a preference for photodissociation over recombination, rendering the parent Ni(II) complex a stable source of a reactive Ni(I) intermediate. Here, we characterize the reversible photochemical behavior of the tethered complex by kinetic analyses, quantum chemical calculations, and ultrafast transient absorption spectroscopy. Comparison to the previously characterized Ni(II)-bpy aryl halide complex indicates that the structural constraints considered here dramatically influence the excited state relaxation pathway and provide insight into the characteristics of excited-state Ni(II)-C bond homolysis and aryl radical reassociation dynamics. This study enriches the understanding of molecular structure effects in photoredox catalysis and offers new possibilities for designing customized photoactive catalysts for precise organic synthesis.

Use of MRI in patients with severe diffuse traumatic brain injury: A matched National Trauma Data Bank analysis.

OBJECTIVE: Magnetic resonance imaging (MRI) is increasingly used to evaluate patients with diffuse traumatic brain injury (dTBI). However, the utility of early MRI is understudied. We hypothesize that early MRI patients will have increased length of stay but no changes in intracranial pressure (ICP) management or disposition. METHODS: The 2019 National Trauma Data Bank was queried for patients with dTBI and Glasgow Coma Scale score ≤8. Extra-axial and focal intra-axial hemorrhages were excluded. Clinical characteristics were controlled for. Patients with and without MRI were compared for ICP management, outcome, mortality, and disposition. A propensity score matching algorithm was used to create a 1:1 match cohort. RESULTS: In 2568 patients, MRI was less common in severe dTBI patients with clear reasons for poor examination, including bilaterally unreactive pupils or midline shift. After matching, 501 patients who underwent MRI within 1 week were compared with 501 patients without MRI. Magnetic resonance imaging patients had longer intensive care unit stays (11.6 ± 9.6 vs. 13.4 ± 9.5, p < 0.01; 95% confidence interval [95% CI], -3.03 to -0.66). There was no difference between groups in ICP monitor (23.6% vs. 27.3%; p = 0.17; 95% CI, -0.09 to 0.02) or ventriculostomy placement (13.6% vs. 13.2%, p = 0.85; 95% CI, -0.04 to 0.05) or in withdrawal of care (15.0% vs. 18.6%, p = 0.12; 95% CI, -0.08 to 0.01). MRI patients were more likely to be discharged to inpatient rehabilitation (42.9% vs. 33.5%; p < 0.01; 95% CI, 0.03-0.15) but not to home (9.4% vs. 9.0%; p = 0.83; 95% CI, -0.03 to 0.04). CONCLUSION: The decision to pursue early brain MRI may be driven by lack of obvious reasons for a patient's poor neurologic status. MRI patients had longer intensive care unit stays but no difference in rates of placement of ICP monitors or ventriculostomies or withdrawal of care. Further study is required to define the role of early MRI in dTBI patients. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level IV.

Trends and Variation in Cervical Spine Imaging Utilization Across Children's Hospitals for Pediatric Trauma.

BACKGROUND: Cervical spine evaluation is a critical component in trauma evaluation, and though several pediatric cervical spine evaluation algorithms have been developed, none has been widely implemented. Here, we assess rates of cervical spine imaging use across children's hospitals, specifically temporal trends in imaging use, variation across hospitals in imaging used, and timing of magnetic resonance imaging in admitted patients. METHODS: Data from the Children's Hospital Associations Pediatric Health Information System was abstracted from 2015 to 2020. Patients less than 18 years of age seen in the emergency department with an International Classification of Diseases (ICD)-10 code indicative of trauma and cervical spine plain radiograph or computed tomography in the emergency department were included. Data visualization and descriptive statistics were used to assess rates of imaging use by age, year, hospital, injury severity, and day of service. Changes in rates of imaging use over time were evaluated via Chi-square test. RESULTS: Across 25,238 patient encounters at 35 children's hospitals, there was an increase in use of cervical spine computed tomography from 2015 to 2020 (28.5 to 36.5%). There was substantial inter-institutional variation in rates of use of plain radiographs versus computed tomography for initial evaluation of the cervical spine across all age groups and regardless of rates of severe injury across institutions. Magnetic resonance imaging was obtained more than three days after admission in 31.5% of intensive care patients who received this imaging. CONCLUSIONS: Increasing use of computed tomography, substantial inter-institutional variation in rates of use of plain radiographs versus computed tomography, and heterogenous timing of magnetic resonance imaging for evaluation of the pediatric cervical spine demonstrate the growing need for development and implementation of an age-specific cervical spine evaluation algorithm to guide judicious use of diagnostic resources. LEVEL OF EVIDENCE: Level III, Epidemiologic.