Randomized feature selection based semi-supervised latent Dirichlet allocation for microbiome analysis.

Health and disease are fundamentally influenced by microbial communities and their genes (the microbiome). An in-depth analysis of microbiome structure that enables the classification of individuals based on their health can be crucial in enhancing diagnostics and treatment strategies to improve the overall well-being of an individual. In this paper, we present a novel semi-supervised methodology known as Randomized Feature Selection based Latent Dirichlet Allocation (RFSLDA) to study the impact of the gut microbiome on a subject's health status. Since the data in our study consists of fuzzy health labels, which are self-reported, traditional supervised learning approaches may not be suitable. As a first step, based on the similarity between documents in text analysis and gut-microbiome data, we employ Latent Dirichlet Allocation (LDA), a topic modeling approach which uses microbiome counts as features to group subjects into relatively homogeneous clusters, without invoking any knowledge of observed health status (labels) of subjects. We then leverage information from the observed health status of subjects to associate these clusters with the most similar health status making it a semi-supervised approach. Finally, a feature selection technique is incorporated into the model to improve the overall classification performance. The proposed method provides a semi-supervised topic modelling approach that can help handle the high dimensionality of the microbiome data in association studies. Our experiments reveal that our semi-supervised classification algorithm is effective and efficient in terms of high classification accuracy compared to popular supervised learning approaches like SVM and multinomial logistic model. The RFSLDA framework is attractive because it (i) enhances clustering accuracy by identifying key bacteria types as indicators of health status, (ii) identifies key bacteria types within each group based on estimates of the proportion of bacteria types within the groups, and (iii) computes a measure of within-group similarity to identify highly similar subjects in terms of their health status.

Pathogenic/likely pathogenic mutations identified in Vietnamese children diagnosed with autism spectrum disorder using high-resolution SNP genotyping platform.

Among the most prevalent neurodevelopmental disorders, Autism Spectrum Disorder (ASD) is highly diverse showing a broad phenotypic spectrum. ASD also couples with a broad range of mutations, both de novo and inherited. In this study, we used a proprietary SNP genotyping chip to analyze the genomic DNA of 250 Vietnamese children diagnosed with ASD. Our Single Nucleotide Polymorphism (SNP) genotyping chip directly targets more than 800 thousand SNPs in the genome. Our primary focus was to identify pathogenic/likely pathogenic mutations that are potentially linked to more severe symptoms of autism. We identified and validated 23 pathogenic/likely pathogenic mutations in this initial study. The data shows that these mutations were detected in several cases spanning multiple biological pathways. Among the confirmed SNPs, mutations were identified in genes previously known to be strongly associated with ASD such as SLCO1B1, ACADSB, TCF4, HCP5, MOCOS, SRD5A2, MCCC2, DCC, and PRKN while several other mutations are known to associate with autistic traits or other neurodevelopmental disorders. Some mutations were found in multiple patients and some patients carried multiple pathogenic/likely pathogenic mutations. These findings contribute to the identification of potential targets for therapeutic solutions in what is considered a genetically heterogeneous neurodevelopmental disorder.

Implementing living-donor pediatric liver transplantation in Southern Vietnam: 15-year results and perspectives.

BACKGROUND: ND2 in Ho Chi Minh City is currently the only public center that performs PLT in Southern Vietnam. In 2005, the first PLT was successfully performed, with support from Belgian experts. This study reviews the implementation of PLT at our center and evaluates the results and challenges. METHODS: Implementation of PLT at ND2 required medico-surgical team building and extensive improvement of hospital facilities. Records of 13 transplant recipients from 2005 to 2020 were studied retrospectively. Short- and long-term complications, as well as the survival rates, were reported. RESULTS: The mean follow-up time was 8.3 ± 5.7 years. Surgical complications included one case of hepatic artery thrombosis that was successfully repaired, one case of colon perforation resulting in death from sepsis, and two cases of bile leak that were drained surgically. PTLD was observed in five patients, of whom three died. There were no cases of retransplantation. The 1-year, 5-year, and 10-year patient survival rates were 84.6%, 69.2%, and 69.2%, respectively. There were no cases of complication or death among the donors. CONCLUSION: Living-donor PLT was developed at ND2 for providing a life-saving treatment to children with end-stage liver disease. Early surgical complication rate was low, and the patient survival rate was satisfactory at 1 year. Long-term survival decreased considerably due to PTLD. Future challenges include surgical autonomy and improvement of long-term medical follow-up with a particular emphasis on prevention and management of Epstein-Barr virus-related disease.

Radiographic and clinical outcomes after definitive spine fusion for skeletally immature patients with idiopathic scoliosis.

PURPOSE: To assess the intermediate-term radiographic and clinical outcomes of skeletally immature idiopathic scoliosis (IS) patients that underwent definitive fusion (DF). METHODS: A retrospective review of patients with IS who were Risser 0 with open tri-radiate cartilages at the time of DF with minimum 5-year follow-up. Outcomes included Scoliosis Research Society (SRS)-30 scores, major Cobb angle, pulmonary function tests (PFTs), and unplanned returns to the operating room (UPROR). Adding-on was defined as progression of the major Cobb angle > 5° or tilt of the lowest instrumented vertebra > 5°. RESULTS: Thirty-two patients (78% female, mean age 12.2 ± 1.3 years old, mean preoperative major Cobb 64.8° ± 15.9) were included. Of these patients, 20 (62.5%) experienced adding-on and 6 (18.8%) required a revision surgery to correct their progressive spinal deformity. Adding-on was associated with lower 5-year postoperative SRS scores for appearance (3.7 ± 0.7 vs 4.4 ± 0.3, p = 0.0126), mental health (4.2 ± 0.6 vs 4.6 ± 0.3, p = 0.0464), satisfaction with treatment (4.0 ± 0.8 vs 4.7 ± 0.4, p = 0.0140), and total score (4.0 ± 0.4 vs 4.4 ± 0.2, p = 0.0035). The results of the PFTs did not differ between groups. Patients experienced an average of 0.53 UPROR/patient. CONCLUSION: DF in skeletally immature patients results in a high rate of adding-on, which adversely affects Health-Related Quality of Life. However, reoperation rates, both planned and unplanned, remain lower when compared to patients undergoing growth-friendly treatment.

The preterm human milk microbiota fluctuates by postpartum week and is characterized by gestational age and maternal BMI.

IMPORTANCE: Despite a growing recognition that the type of nutrition received by preterm infants influences their intestinal microbiome and health outcomes, the microbiota of mother's own milk (MOM), pasteurized donor human milk (PDHM), and infant formula remain poorly characterized. In our study, we found that the structure of microbial communities, bacterial diversity, and relative abundances of specific genera were significantly different between MOM, PDHM, and formula. Additionally, our results suggest that the microbiota of MOM changes as a function of time and maternal factors. Lastly, we identified three lactotypes within MOM that have distinct microbial compositions and described the maternal factors associated with them. These findings set the stage for future research aimed at advancing our knowledge of the microbiota of preterm infant nutrition and the specific influence it may have on health outcomes.

A study on biomedical researchers' perspectives on public engagement in Southeast Asia.

Introduction: Public engagement is increasingly promoted in the scientific community. Although there are studies about researchers' perspectives on public engagement, these are predominantly from Global North settings and there is little data from the context of Southeast Asia. The Oxford University Clinical Research Unit (OUCRU) is a clinical and public health research programme with sites in Vietnam, Nepal and Indonesia. There is a dedicated public engagement team, and it is recognised as an important part of the research process.   Methods: Through this study we explored the views and needs of local researchers with regards to practicing public engagement. We obtained opinions of 70 researchers through an online survey with both open-ended and closed-ended questions.   Results: Most researchers perceived public engagement as improving public science literacy, rather than supporting public participation in science and research. While the participants largely see public engagement as a necessary practice, they experienced four main barriers to taking part in public engagement: time, lack of capacity, lack of support and personal perceptions. Most participants indicated they had somewhat to low confidence to communicate about science to the public. Experience, skill and knowledge, and personal preference emerged as factors that influence their perceived confidence for science communication. In our analysis, experience appeared to be the main factor contributing to researchers' high confidence.   Recommendations: We recommended to support researchers by not only providing them with training for skills and knowledge, but also with opportunities to conduct public engagement, and a range of methods to suit their personal styles of communicating. It is also evident that more support is needed to build an enabling institutional environment that gives researchers professional recognition for their engagement work. This study, while modest in its scope, has informed our approach to supporting researcher-led engagement, and may guide other institutes wishing to improve this.

Lessons for Vietnam on the Use of Digital Technologies to Support Patient-Centered Care in Low- and Middle-Income Countries in the Asia-Pacific Region: Scoping Review.

BACKGROUND: A rapidly aging population, a shifting disease burden and the ongoing threat of infectious disease outbreaks pose major concerns for Vietnam's health care system. Health disparities are evident in many parts of the country, especially in rural areas, and the population faces inequitable access to patient-centered health care. Vietnam must therefore explore and implement advanced solutions to the provision of patient-centered care, with a view to reducing pressures on the health care system simultaneously. The use of digital health technologies (DHTs) may be one of these solutions. OBJECTIVE: This study aimed to identify the application of DHTs to support the provision of patient-centered care in low- and middle-income countries in the Asia-Pacific region (APR) and to draw lessons for Vietnam. METHODS: A scoping review was undertaken. Systematic searches of 7 databases were conducted in January 2022 to identify publications on DHTs and patient-centered care in the APR. Thematic analysis was conducted, and DHTs were classified using the National Institute for Health and Care Excellence evidence standards framework for DHTs (tiers A, B, and C). Reporting was in line with the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews) guidelines. RESULTS: Of the 264 publications identified, 45 (17%) met the inclusion criteria. The majority of the DHTs were classified as tier C (15/33, 45%), followed by tier B (14/33, 42%) and tier A (4/33, 12%). At an individual level, DHTs increased accessibility of health care and health-related information, supported individuals in self-management, and led to improvements in clinical and quality-of-life outcomes. At a systems level, DHTs supported patient-centered outcomes by increasing efficiency, reducing strain on health care resources, and supporting patient-centered clinical practice. The most frequently reported enablers for the use of DHTs for patient-centered care included alignment of DHTs with users' individual needs, ease of use, availability of direct support from health care professionals, provision of technical support as well as user education and training, appropriate governance of privacy and security, and cross-sectorial collaboration. Common barriers included low user literacy and digital literacy, limited user access to DHT infrastructure, and a lack of policies and protocols to guide the implementation and use of DHTs. CONCLUSIONS: The use of DHTs is a viable option to increase equitable access to quality, patient-centered care across Vietnam and simultaneously reduce pressures on the health care system. Vietnam can take advantage of the lessons learned by other low- and middle-income countries in the APR when developing a national road map to digital health transformation. Recommendations that Vietnamese policy makers may consider include emphasizing stakeholder engagement, strengthening digital literacy, supporting the improvement of DHT infrastructure, increasing cross-sectorial collaboration, strengthening governance of cybersecurity, and leading the way in DHT uptake.

Recanalization Treatments for Pediatric Acute Ischemic Stroke in France.

Importance: There is to date limited evidence that revascularization strategies are associated with improved functional outcome in children with acute ischemic stroke (AIS). Objectives: To report clinical outcomes and provide estimates of revascularization strategy safety and efficacy profiles of intravenous thrombolysis (IVT) and/or endovascular treatment (EVT) in children with AIS. Design, Setting, and Participants: The KidClot multicenter nationwide cohort study retrospectively collected data of children (neonates excluded) with AIS and recanalization treatment between January 1, 2015, and May 31, 2018. Data analysis was performed from January 1, 2015, to May 31, 2019. Exposure: IVT and/or EVT. Main Outcomes and Measures: Primary outcome was day 90 favorable outcome (modified Rankin Scale [mRs] 0-2, with 0 indicating no symptoms and 6 indicating death). Secondary end points included 1-year favorable outcome (mRs, 0-2), mortality, and symptomatic intracerebral hemorrhage. Other measures included the Pediatric National Institutes of Health Stroke Scale (pedNIHSS), with pedNIHSS 0 indicating no symptoms, 1 to 4 corresponding to a minor stroke, 5 to 15 corresponding to a mild stroke, greater than 15 to 20: severe stroke, and the adult Alberta Stroke Program Early CT Score (ASPECTS), which provides segmental assessment of the vascular territory, with 1 point deducted from the initial score of 10 for every region involved (from 10 [no lesion] to 0 [maximum lesions]). Results: Overall, 68 children were included in 30 centers (IVT [n = 44]; EVT [n = 40]; 44 boys [64.7%]; median [IQR] age, 11 [4-16] years; anterior circulation involvement, 57 [83.8%]). Median (IQR) pedNIHSS score at admission was 13 (7-19), higher in the EVT group at 16 (IQR, 10-20) vs 9 (6-17) in the IVT only group (P < .01). Median time from stroke onset to imaging was higher in the EVT group at 3 hours and 7 minutes (IQR, 2 hours and 3 minutes to 6 hours and 24 minutes) vs 2 hours and 39 minutes (IQR, 1 hour and 51 minutes to 4 hours and 13 minutes) (P = .04). Median admission ASPECTS score was 8 (IQR, 6-9). The main stroke etiologies were cardioembolic (21 [30.9%]) and focal cerebral arteriopathy (17 [25.0%]). Median (IQR) time from stroke onset to IVT was 3 hours and 30 minutes (IQR, 2 hours and 33 minutes to 4 hours and 28 minutes). In the EVT group, the rate of postprocedure successful reperfusion (≥modified Treatment in Cerebral Infarction 2b) was 80.0% (32 of 40). Persistent proximal arterial stenosis was more frequent in focal cerebral arteriopathy (P < .01). Death occurred in 3 patients (4.4%). Median pedNIHSS reduction at 24 hours was 4 (IQR, 0-9) points. Intracerebral hemorrhage occurred in 4 patients and symptomatic intracerebral hemorrhage occurred in 1 patient, all in the EVT group. The median mRS was 2 (IQR, 0-3) at day 90 and 1 (IQR, 0-2) at 1 year, which was not significantly different between EVT and IVT only groups, although different in initial severity. Conclusions and Relevance: The findings of this cohort study suggest that use of EVT and/or IVT is safe in children with AIS.

Pb(II) adsorption mechanism and capability from aqueous solution using red mud modified by chitosan.

Red mud modified by chitosan (RM/CS) was utilized as an adsorbent to effectively remove Pb(II) from aqueous solution. The surface area of RM/CS was found to significantly increase by more than 50% compared to that of original red mud. Different factors that affected the Pb(II) removal on this material, such as initial Pb(II) concentration, pH, and contact time, were investigated. The pseudo-first-order, pseudo-second-order, and intra-diffusion models were used to fit the experimental data to investigate the Pb(II)'s removal kinetics. The Pb(II) removal followed the intra-diffusion model. Additionally, the non-zero C value obtained from this model indicates that the removal was controlled by many different mechanisms. We also found that the interaction of Pb(II) and carbonate group on the material's surface played a primary role once the adsorption equilibrium was reached. Finally, the maximum adsorptive capacity was found to be about 209 mg/g. This obtained value is higher than those obtained for some other materials. Therefore, the present RM/CS should be a potential material for removing Pb(II) from aqueous solution.

Recycled Concrete Aggregate for Medium-Quality Structural Concrete.

This paper reports an evaluation of the properties of medium-quality concrete incorporating recycled coarse aggregate (RCA). Concrete specimens were prepared with various percentages of the RCA (25%, 50%, 75%, and 100%). The workability, mechanical properties, and durability in terms of abrasion of cured concrete were examined at different ages. The results reveal insignificant differences between the recycled concrete (RC) and reference concrete in terms of the mechanical and durability-related measurements. Meanwhile, the workability of the RC reduced vastly since the replacement of the RCA reached 75% and 100%. The ultrasound pulse velocity (UPV) results greatly depend on the porosity of concrete and the RC exhibited higher porosity than that of the reference concrete, particularly at the transition zone between the RCA and the new paste. Therefore, the sound transmission in the RC required longer times than that in the reference concrete. Moreover, a predictive equation relating the compressive strength to the UPV was developed.

Post-Hoc Analysis of a Randomized, Double Blind, Prospective Study at the University of Chicago: Additional Standardizations of Trial Protocol are Needed to Evaluate the Effect of a CXCR1/2 Inhibitor in Islet Allotransplantation.

A recent randomized, multicenter trial did not show benefit of a CXCR1/2 receptor inhibitor (Reparixin) when analysis included marginal islet mass (>3,000 IEQ/kg) for allotransplantation and when immunosuppression regimens were not standardized among participating centers. We present a post-hoc analysis of trial patients from our center at the University of Chicago who received an islet mass of over 5,000 IEQ/kg and a standardized immunosuppression regimen of anti-thymocyte globulin (ATG) for induction. Twelve islet allotransplantation (ITx) recipients were randomized (2:1) to receive Reparixin (N = 8) or placebo (N = 4) in accordance with the multicenter trial protocol. Pancreas and donor characteristics did not differ between Reparixin and placebo groups. Five (62.5%) patients who received Reparixin, compared to none in the placebo group, achieved insulin independence after only one islet infusion and remained insulin-free for over 2 years (P = 0.08). Following the first ITx with ATG induction, distinct cytokine, chemokine, and miR-375 release profiles were observed for both the Reparixin and placebo groups. After excluding procedures with complications, islet engraftment on post-operative day 75 after a single transplant was higher in the Reparixin group (n = 7) than in the placebo (n = 3) group (P = 0.03) when islet graft function was measured by the ratio of the area under the curve (AUC) for c-peptide to glucose in mixed meal tolerance test (MMTT). Additionally, the rate of engraftment was higher when determined via BETA-2 score instead of MMTT (P = 0.01). Our analysis suggests that Reparixin may have improved outcomes compared to placebo when sufficient islet mass is transplanted and when standardized immunosuppression with ATG is used for induction. However, further studies are warranted. Investigation of Reparixin and other novel agents under more standardized and optimized conditions would help exclude confounding factors and allow for a more definitive evaluation of their role in improving outcomes in islet transplantation. Clinical trial reg. no. NCT01817959, clinicaltrials.gov.

Real-Time Analysis of Polyphenol-Protein Interactions by Surface Plasmon Resonance Using Surface-Bound Polyphenols.

A selection of bioactive polyphenols of different structural classes, such as the ellagitannins vescalagin and vescalin, the flavanoids catechin, epicatechin, epigallocatechin gallate (EGCG), and procyanidin B2, and the stilbenoids resveratrol and piceatannol, were chemically modified to bear a biotin unit for enabling their immobilization on streptavidin-coated sensor chips. These sensor chips were used to evaluate in real time by surface plasmon resonance (SPR) the interactions of three different surface-bound polyphenolic ligands per sensor chip with various protein analytes, including human DNA topoisomerase IIα, flavonoid leucoanthocyanidin dioxygenase, B-cell lymphoma 2 apoptosis regulator protein, and bovine serum albumin. The types and levels of SPR responses unveiled major differences in the association, or lack thereof, and dissociation between a given protein analyte and different polyphenolic ligands. Thus, this multi-analysis SPR technique is a valuable methodology to rapidly screen and qualitatively compare various polyphenol-protein interactions.

Pregnancy-induced humoral sensitization overrides T cell tolerance to fetus-matched allografts in mice.

Immunological tolerance to semiallogeneic fetuses is necessary to achieving successful first pregnancy and permitting subsequent pregnancies with the same father. Paradoxically, pregnancy is an important cause of sensitization, resulting in the accelerated rejection of offspring-matched allografts. The underlying basis for divergent outcomes following reencounter of the same alloantigens on transplanted organs versus fetuses in postpartum females is incompletely understood. Using a mouse model that allows concurrent tracking of endogenous fetus-specific T and B cell responses in a single recipient, we show that semiallogeneic pregnancies simultaneously induce fetus-specific T cell tolerance and humoral sensitization. Pregnancy-induced antibodies, but not B cells, impeded transplantation tolerance elicited by costimulation blockade to offspring-matched cardiac grafts. Remarkably, in B cell-deficient mice, allogeneic pregnancy enabled the spontaneous acceptance of fetus-matched allografts. The presence of pregnancy-sensitized B cells that cannot secrete antibodies at the time of heart transplantation was sufficient to precipitate rejection and override pregnancy-established T cell tolerance. Thus, while induction of memory B cells and alloantibodies by pregnancies establishes formidable barriers to transplant success for multigravid women, our observations raise the possibility that humoral desensitization will not only improve transplantation outcomes, but also reveal an unexpected propensity of multiparous recipients to achieve tolerance to offspring-matched allografts.

Primary biosorption mechanism of lead (II) and cadmium (II) cations from aqueous solution by pomelo (Citrus maxima) fruit peels.

The present work investigates the primary adsorption mechanisms of lead (II) and cadmium (II) cations onto pomelo fruit peel (PFP) from aqueous solution. pH, adsorption time, ion strength, and initial metal cation concentrations, which are factors affecting the uptake of these cations, are investigated. Results show that pH and ion strengths strongly affect the removal of these cations from aqueous solution. Different isotherm adsorption models, such as Langmuir, Freundlich, and Sips, are utilized to fit the experimental data in order to determine the adsorption in nature. The Langmuir monolayer adsorption capacities are found to be 47.18 mg/g for lead (II) and 13.35 mg/g for cadmium (II). Kinetic and thermodynamic studies based on a combination of FT-IR and TG-DSC spectroscopies demonstrate that electrostatic attraction plays a primary adsorption mechanism of lead (II) and cadmium (II) cations onto pomelo fruit peel.

A Screening of Neuraminidase Inhibition Activities of Isoquinolone Alkaloids in Coptis chinensis Using Molecular Docking and Pharmacophore Analysis.

Coptis chinensis has been long used as the potential herbal remedy for the treatment of influenza A infection. The six isoquinolone alkaloids extracted from C. chinensis rhizomes are reported to have good inhibition activity on neuraminidase (NA) of Clostridium perfringens, A/H1N1/1918, and recombinant NA-1; however, the study of the effect of these candidates on other NAs of threatening influenza A causing pandemic and seasonal flu recently has not considered yet. The purpose of this study is to investigate the interaction between these compounds and NAs of different wild and mutant subtypes of influenza A. This process involved the molecular docking of 3D structures of those compounds (ligand) into target proteins NA of A/H1N1/1918, A/H1N1/2009pdm, H3N2/2010 wild type, H3N2/2010 D151G mutant, H5N1 wild type, and H5N1 H274Y mutant. Then, the Protein-Ligand Interaction Profiler (PLIP) was utilized to demonstrate the bond formed between the ligand and the binding pocket of receptors of interest. The results showed that six candidates including palmatine, berberine, jatrorrhizine, epiberberine, columbamine, and coptisine have a higher affinity to all six selected proteins than commercial drugs such as oseltamivir, zanamivir, and natural binding ligand sialic acid. The results could be explained via the 2D picture, which showed the hydrophobic interaction and hydrogen bonding forming between the oxygen molecules of the ligand with the free residue of proteins.

How Should Shared Decision Making Be Taught?

As the field of medicine shifts from a paternalistic to a more patient-centered orientation, the dynamics of shared decision making become increasingly complicated. International globalization and national socioeconomic differences have added unintended difficulties to culturally sensitive communication between physician and patient, which can contribute to the growing erosion of clinician empathy. This article offers a strategy for teaching students how to enter into conversations about shared decision making by bolstering their empathy as a result of exposing them to the many variables outside of their patients' control. Patients' historical and cultural context, gender identity, sexual orientation, and common assumptions about clinicians as well as institutional biases can severely limit students' ability to integrate patients' value-laden preferences into shared decision making about health care.

Arterial ischemic stroke in non-neonate children: Diagnostic and therapeutic specificities.

Pediatric arterial ischemic stroke (AIS) is a severe condition, with long-lasting devastating consequences on motor and cognitive abilities, academic and social inclusion, and global life projects. Awareness about initial symptoms, implementation of pediatric stroke code protocols using MRI first and only and adapted management in the acute phase, individually tailored recanalization treatment strategies, and multidisciplinary rehabilitation programs with specific goal-centered actions are the key elements to improve pediatric AIS management and outcomes. The main cause of pediatric AIS is focal cerebral arteriopathy, a condition with unilateral focal stenosis and time-limited course requiring specific management. Sickle cell disease and moyamoya angiopathy patients need adapted screening and therapeutics.

Delay to Surgery Greater Than 6 Months Leads to Substantial Deformity Progression and Increased Intervention in Immature Adolescent Idiopathic Scoliosis (AIS) Patients: A Retrospective Cohort Study.

DESIGN: A retrospective, multi-institution series of adolescent idiopathic scoliosis (AIS) patients whose date of surgery exceeded six months from date of surgical recommendation were identified. A case-matched comparison of surgical outcomes of skeletally immature patients who delayed surgery versus a cohort of nondelayed patients. OBJECTIVES: We sought to identify 1) whether patients at risk for significant curve progression when delaying surgery could be identified with available clinical and radiographic data and 2) whether patients who delay surgery have longer fusions/more complex procedures. BACKGROUND: Multiple factors can lead to a delay in treatment of AIS once surgical treatment is recommended, and larger Cobb magnitudes have been associated with a more complex surgery. METHODS: 143 AIS patients who delayed surgery had deformity progression (major Cobb angle change over time) analyzed by Risser grade, triradiate cartilage (TRC) status, and menarche status. Comparison of at-risk patients with regard to surgical outcomes to a cohort of matched patients who had not delayed surgery. RESULTS: Risser 0 patients (n = 34) had a greater major Cobb progression than Risser 1-5 patients (n = 109): mean 1.6°/mo versus 0.4°/mo, p < .001. Twenty-eight premenarchal patients had significantly greater increases in Cobb angle measures than their postmenarchal counterparts (n = 86) (13.2° vs. 4.3°, p < .001). An open TRC also conferred increasing rate of progression. Radiographic variables of stable vertebra and last vertebra touched by central sacral vertical line were more likely to change in immature patients, but we did not demonstrate longer fusions or higher estimated blood loss as a result when compared to nondelayed, age-matched peers. CONCLUSION: AIS patients who are premenarchal, TRC open, or Risser 0 who delay surgery greater than 6 months risk clinically significant Cobb angle progression, which is statistically greater than their more mature peers. Clinical ramifications of this remain unclear. Skeletally mature patients do not progress rapidly, allowing elective timing of surgical intervention. LEVEL OF EVIDENCE: Level III.

COMPARISON OF IMPLANT DENSITY IN THE MANAGEMENT OF LENKE 1B AND 1C ADOLESCENT IDIOPATHIC SCOLIOSIS.

OBJECTIVE: To compare radiographic and surgical outcomes of Lenke 1B and 1C patterns. METHODS: One hundred twenty patients with Lenke 1B and 1C scoliosis were grouped according to implant density as follows: low density (LD) of ≤1.4 and high density (HD) of >1.4. Matched subgroups (30 patients each) based on age, curve magnitude, and body mass index (BMI) were analyzed. Radiographic parameters were evaluated before operation, immediately after operation (ipo), and at 2 years' follow-up. SRS-30 was administered before operation and at 2 years' follow-up. RESULTS: The major curves of the LD (n = 82) and HD groups (n=38) were respectively 59.1° and 65.6° before operation (p <.001), 26.3° and 22.9° ipo (p =.05), and 29.9° and 19.8° at 2 years' follow-up (p <.001). No significant differences in postoperative trunk shift and coronal balance were found (p =.69 and p =.74, respectively). The HD group had higher blood loss (p =.02), number of implants (p <.001), levels fused (p =.002), and surgical time (p <.001). The HD group had a higher prevalence of hypokyphosis from before operation to follow-up (p <.001). No significant differences were observed in the SRS-30 scores before operation and at 2 years' follow-up. The matched groups had similar preoperative major curves (p =.56), ages (p =.75), and BMIs (p =.61). Significantly longer surgical time (p =.009), higher density (p <.001), and better correction (p =.0001) were found in the HD group at 2 years' follow-up. No significant differences were found in the SRS-30 scores before operation and at 2 years' follow-up. CONCLUSION: LD constructs included fewer segments fused, lower intraoperative estimated surgical blood loss, and shorter operation time, and potentially decreasing complication risks due to fewer implants. Level of evidence III, Retrospective Cohort Study.

OBJETIVO: Comparar os desfechos radiográficos e cirúrgicos da escoliose Lenke 1B e 1C. MÉTODOS: Cento e vinte pacientes com escoliose Lenke 1B e 1C foram agrupados de acordo com a densidade do implante, como segue: baixa densidade (BD) de ≤ 1,4 e alta densidade (AD) de > 1,4. Foram analisados os grupos pareados (30 pacientes cada) com base na idade, magnitude da curva e índice de massa corporal (IMC). Os parâmetros radiográficos foram avaliados antes da cirurgia, no pós-operatório imediato (POI) e no acompanhamento de dois anos. O questionário SRS-30 foi administrado antes da cirurgia e no acompanhamento de dois anos. RESULTADOS: As principais curvas dos grupos BD (n = 82) e AD (n = 38) foram respectivamente 59,1° e 65,6° antes da operação (p < 0,001), 26,3° e 22,9° no POI (p = 0,05) e 29,9° e 19,8° aos 2 anos de acompanhamento (p < 0,001). Não foram encontradas diferenças significantes no desvio do tronco e no balanço coronal no pós-operatório (p = 0,69 e p = 0,74, respectivamente). O grupo AD teve mais perda sanguínea (p = 0,02), número de implantes (p < 0,001), níveis de fusão (p = 0,002) e tempo de cirurgia (p < 0,001). O grupo AD teve maior prevalência de hipocifose do período anterior à cirurgia até o acompanhamento (p < 0,001). Não houve diferenças significantes nas pontuações do SRS-30 antes da operação e aos 2 anos de acompanhamento. No pré-operatório, os grupos pareados tinham curvas principais (p = 0,56), idade (p = 0,75) e IMC (p = 0,61) semelhantes. Constatou-se tempo cirúrgico expressivamente maior (p = 0,009), maior densidade (p < 0,001) e melhor correção (p = 0,0001) no grupo AD aos 2 anos de acompanhamento. Não foram encontradas diferenças significantes nas pontuações do SRS-30 antes da cirurgia e no acompanhamento de 2 anos. CONCLUSÃO: As estruturas de BD incluíram menos segmentos fundidos, menor perda de sangue intraoperatória estimada, menor tempo de cirurgia e menos risco de complicações, com possibilidade de redução, por causa do menor número de implantes. Nível de evidência III, Estudo retrospectivo de coorte.