An enhanced photo(electro)catalytic CO2 reduction onto advanced BiOX (X = Cl, Br, I) semiconductors and the BiOI-PdCu composite.

The photoelectrocatalytic reduction of CO2 (CO2RR) onto bismuth oxyhalides (BiOX, X = Cl, Br, I) was studied through physicochemical and photoelectrochemical measurements. The successful synthesis of the BiOX compounds was carried out through a solvothermal methodology and confirmed by XRD measurements. The morphology was analyzed by SEM; meanwhile, area and pore size were determined through BET area measurements. BiOI and BiOCl present a lower particle size (3.15 and 2.71 µm, respectively); however, the sponge-like morphology presented by BiOI results in an increase in the BET area, which can enhance the catalytic activity of this semiconductor. In addition, DRS measurements allowed us to determine bandgap values of 1.9, 2.4, and 3.6 eV for BiOI, BiOBr, and BiOCl, respectively. Such results predict better visible light harvesting for BiOI. Photoelectrochemical measurements indicated that BiOX shows p-type semiconductor behavior, being the holes the majority charge carriers, making BiOI the most active material to carry out photoelectrocatalytic CO2RR. In the second stage, three different composites, BiOI-Pd, BiOI-Cu, and BiOI-PdCu, (BiOI-M; M = Pd, Cu, PdCu), were fabricated to study the influence of active metal nanoparticles (NP's) in the BiOI CO2RR activity. XRD measurements confirmed the interaction between BiOI and the metallic NP's, the three composites overpassed by 20% the BET area of pristine BiOI. Photoelectrochemical measurements indicate that all BiOI-metal composites are suitable materials to perform CO2 reduction in neutral media efficiently; however, the BiOI-PdCu composites surpassed the faradaic current of BiOI-Pd and BiOI-Cu at 0.85 V vs. RHE (3.15, 2.06 and 2.15 mA cm-2, respectively). BiOI-PdCu presented photoactivity to carry out the CO2 reduction evolving formic acid and acetic acid as the main products under visible-light irradiation.

Subependymal giant-cell astrocytomas in the absence of tuberous sclerosis.

OBJECTIVE: Tuberous sclerosis is a rare genetic condition caused by TSC1 or TSC2 mutations that can be inherited, sporadic, or the result of somatic mosaicism. Subependymal giant-cell astrocytoma (SEGA) is a major diagnostic feature of tuberous sclerosis complex (TSC). This study aimed to present a series of cases in which a pathological diagnosis of SEGA was not diagnostic of tuberous sclerosis. METHODS: The authors retrospectively reviewed a clinical case series of 5 children who presented with a SEGA tumor to Johns Hopkins All Children's Hospital and St. Louis Children's Hospital between 2010 and 2022 and whose initial genetic workup was negative for tuberous sclerosis. All patients were treated with craniotomy for SEGA resection. TSC genetic testing was performed on all SEGA specimens. RESULTS: The children underwent open frontal craniotomy for SEGA resection from the ages of 10 months to 14 years. All cases demonstrated the classic imaging features of SEGA. Four were centered at the foramen of Monro and 1 in the occipital horn. One patient presented with hydrocephalus, 1 with headaches, 1 with hand weakness, 1 with seizures, and 1 with tumor hemorrhage. Somatic TSC1 mutation was present in the SEGA tumors of 2 patients and TSC2 mutation in 1 patient. Germline TSC mutation testing was negative for all 5 cases. No patient had other systemic findings of tuberous sclerosis on ophthalmological, dermatological, neurological, renal, or cardiopulmonary assessments and thus did not meet the clinical criteria for tuberous sclerosis. The average follow-up was 6.7 years. Recurrence was noted in 2 cases, in which 1 patient underwent radiosurgery and 1 was started on a mammalian target of rapamycin (mTOR) inhibitor (rapamycin). CONCLUSIONS: There may be intracranial implications of somatic mosaicism associated with tuberous sclerosis. Children who are diagnosed with SEGA do not necessarily have a diagnosis of tuberous sclerosis. Tumors may carry a TSC1 or TSC2 mutation, but germline testing can be negative. These children should continue to be followed with serial cranial imaging for tumor progression, but they may not require the same long-term monitoring as patients who are diagnosed with germline TSC1 or TSC2 mutations.

Endoscopic Placement of Intracystic Catheters: A Technical Note.

BACKGROUND: Intraventricular neuroendoscopic surgery for tumor resection, biopsy, or cyst fenestration frequently requires precise placement of an intraventricular or intracystic catheter. Placement under direct visualization is not feasible because of small bore of working channel of the standard small ventriculoscope. Various techniques have been reported using a separate transcortical trajectory, endoluminal endoscope, or endovascular guide wire. OBJECTIVE: To describe a technique allowing precise placement of intraventricular/intracystic catheter using a small bore working ventriculoscope, without need for additional equipment. METHODS: Description of the technique including intraoperative photographs, video, and illustrative cases are provided. RESULTS: The peel-away sheath is peeled off approximately 1 to 2 cm to allow for the shaft of the endoscope to pass past its tip. Ventricular access is gained using the peel-away sheath. After the stylet is removed, the peel-away sheath is not peeled further or stapled to the skin. The endoscope is introduced into the ventricle through the peel-away sheath. After the required intraventricular work is performed, the endoscope is maneuvered into the location of the desired catheter position. The peel-away sheath is slowly advanced over the stationary endoscope past its tip. While the peel-away sheath is being held in place, the endoscope is removed. After the catheter has been introduced into the peel-away sheath to a premeasured depth, the peel-away sheath is peeled and removed. The catheter is then connected to collection system, reservoir or shunt system. CONCLUSION: The current technique allows for the precise placement of intraventricular/intracystic catheters without the need for additional equipment or a separate transcortical trajectory.

Clinical experience of thoracoplasty with absorbable rib substitutes.

PURPOSE: Malignant chest wall tumors are rare in pediatrics. They require multimodal oncological treatment and local surgical control. Resections are extensive; therefore, thoracoplasty should be planned to protect intrathoracic organs, prevent herniation, future deformities, preserve ventilatory dynamics, and enable radiotherapy. METHODS: We present a case series of children with malignant chest wall tumors and our surgical experience with thoracoplasty using absorbable rib substitutes (BioBridge®), after local surgical control. BioBridge® is a copolymer made of a polylactide acid blend (70% L-lactic acid y 30% DL-lactide). RESULTS: In 2 years, we had three patients with malignant chest wall tumors. Resection margins were negative, without recurrence at follow-up. We achieved good cosmetic and functional results, and no postoperative complications. CONCLUSION: Alternative reconstruction techniques such as absorbable rib substitutes provide protection, guarantee a flexible chest wall, and do not interfere with adjuvant radiotherapy. Currently, there are no management protocols in thoracoplasty. This option represents an excellent alternative for patients with chest wall tumors. Knowledge of different approaches and reconstructive principles is essential to offer children the best onco-surgical option.

Pediatric mild head trauma: is outpatient follow-up imaging necessary or beneficial?

OBJECTIVE: Pediatric traumatic brain injury (TBI) is the leading cause of death among children and is a significant cause of morbidity. However, the majority of injuries are mild (Glasgow Coma Scale score 13-15) without any need for neurosurgical intervention, and clinically significant neurological decline rarely occurs. Although the question of repeat imaging within the first 24 hours has been discussed in the past, the yield of short-term follow-up imaging has never been thoroughly described. In this paper, the authors focus on the yield of routine repeat imaging for pediatric mild TBI (mTBI) at the first clinic visit following hospital discharge. METHODS: The authors conducted a retrospective review of patients with pediatric brain trauma who had been admitted to Johns Hopkins All Children's Hospital (JHACH). Patients with mTBI were identified, and their presentation, hospital course, and imaging results were reviewed. Those pediatric patients with mTBI who had undergone no procedure during their initial admission (only conservative treatment) were eligible for inclusion in the study. Two distinct groups were identified: patients who underwent repeated imaging at their follow-up clinic visit and those who underwent only clinical evaluation. Each case was assessed on whether the follow-up imaging had changed the follow-up course. RESULTS: Between 2010 and 2015, 725 patients with TBI were admitted to JHACH. Of those, 548 patients qualified for analysis (i.e., those with mTBI who received conservative treatment without any procedure and were seen in the clinic for follow-up evaluation within 8 weeks after the trauma). A total of 392 patients had only clinic follow-up, without any diagnostic imaging study conducted as part of their clinic visit, whereas the other 156 patients underwent repeat MRI. Only 1 patient had a symptomatic change and was admitted after undergoing imaging. For 30 patients (19.2%), it was decided after imaging to continue the neurosurgical follow-up, which is a change from the institutional paradigm after mTBI. None of these patients had a change in neurological status, and all had a good functional status. All of these patients had one more follow-up in the clinic with new MRI, and none of them required further follow-up. CONCLUSIONS: Children with mTBI are commonly followed up in the ambulatory clinic setting. The authors believe that for children with mTBI, normal clinical examination, and no new symptoms, there is no need for routine ambulatory imaging since the clinical yield of such is relatively low.

Double cropping and cropland expansion boost grain production in Brazil.

Brazilian grain production increased more than fourfold from 1980 to 2016. The grain boom was achieved primarily by soybean-corn double cropping and cropland expansion-both show changing spatiotemporal patterns since the 1980s. Here, we quantified the contributions of these two strategies to corn and soybean production in Brazil using municipality-level data from 1980 to 2016. We found the contribution of double cropping to the grain boom steadily increased to 35% and the largest driving force was the increasing demand for grain export. While double cropping dominated the conventional agricultural regions, cropland expansion was still the major strategy in agricultural frontiers such as the Centre-West and Matopiba. The implementation of double cropping offset the equivalent of 76.7 million ha of Brazilian arable land for grain production from 2003 to 2016. Double cropping in Brazil has the potential to help alleviate land burdens in other pantropical countries with increasing global food demand.

Flux synthesis of Ba2Li2/3Ti16/3O13 and its photocatalytic performance.

Barium-lithium titanate (Ba2Li2/3Ti16/3O13) was synthesized by using a flux method under some conditions with various chloride salts as the flux, thermal treatment temperatures, solute concentrations, and cooling rates. As a result, fine particles of this material with a rod-like morphology were obtained for the first time. It is suggested that this morphology with high crystallinity is responsible for the increase in the photocatalytic activity of this material without any co-catalyst for H2 and CO evolution from water and CO2. The observed photocatalytic performance is discussed taking into consideration the differences in physicochemical properties, obtained as a result of the synthesis using this method under the different conditions.

Incidentally found brain tumors in the pediatric population: a case series and proposed treatment algorithm.

PURPOSE: With the increasing use of imaging, there has been an increase in the number of incidentally found brain lesions in pediatric patients resulting in a treatment dilemma for physicians and emotional strain for patients and families. Adult studies support initial surveillance of incidentally found low grade appearing lesions as the most appropriate approach. The aim of this study was to evaluate incidental lesions in the pediatric population and propose an initial treatment algorithm for such lesions. METHODS: Pediatric records were retrospectively reviewed at Johns Hopkins All Children's Hospital for incidentally found brain tumors between 2000 and 2017. Demographic data, presenting symptoms, treatment approach, and outcomes were reviewed for 55 patients, age 0-18. RESULTS: Of the 55 patients included in the study, 14 underwent surgical resection, 3 underwent biopsy, and 38 with benign imaging characteristics at presentation were monitored with radiology alone. Only one patient, out of the 17 that underwent resection or biopsy, had pathology consistent with a high grade glioma. Of the patients monitored radiographically 10 total patients showed an increase in the overall size of the lesion; however after a median follow up of 34.2 months only 2 increased to a degree that required surgical intervention. CONCLUSIONS: The majority of incidentally found brain lesions with benign imaging characteristics at presentation may be managed conservatively. Surveillance is an important part of the initial management of incidental lesions in the pediatric population, but careful scrutiny must be paid to the potential for higher grade lesions or malignant transformation.

The Preventable Shunt Revision Rate: A Multicenter Evaluation.

BACKGROUND: The Preventable Shunt Revision Rate (PSRR) was recently introduced as a novel quality metric. OBJECTIVE: To evaluate the PSRR across multiple centers and determine associated variables. METHODS: Nine participating centers in North America provided at least 2 years of consecutive shunt operations. Index surgery was defined as new shunt implantation, or revision of an existing shunt. For any index surgery that resulted in a reoperation within 90-days, index surgery information (demographic, clinical, and procedural) was collected and a decision made whether the failure was potentially preventable. The 90-day shunt failure rate and PSRR were calculated per institution and combined. Bivariate analyses were performed to evaluate individual effects of each independent variable on preventable shunt failure followed by a final multivariable model using a backward model selection approach. RESULTS: A total of 5092 shunt operations were performed; 861 failed within 90 days of index operation, resulting in a 16.9% combined 90-day shunt failure rate and 17.6% median failure rate (range, 8.7%-26.9%). Of the failures, 307 were potentially preventable (overall and median 90-day PSRR, 35.7% and 33.9%, respectively; range, 16.1%-55.4%). The most common etiologies of avoidable failure were infection (n = 134, 44%) and proximal catheter malposition (n = 83, 27%). Independent predictors of preventable failure (P < .05) were lack of endoscopy (odds ratio [OR] = 2.26), recent shunt infection (OR = 3.65), shunt type (OR = 2.06) and center. CONCLUSION: PSRR is variable across institutions, but can be 50% or higher. While the PSRR may never reach zero, this study demonstrates that overall about a third of early failures are potentially preventable.

Growth and alignment of the pediatric subaxial cervical spine following rigid instrumentation and fusion: a multicenter study of the Pediatric Craniocervical Society.

OBJECTIVE The long-term effects of surgical fusion on the growing subaxial cervical spine are largely unknown. Recent cross-sectional studies have demonstrated that there is continued growth of the cervical spine through the teenage years. The purpose of this multicenter study was to determine the effects of rigid instrumentation and fusion on the growing subaxial cervical spine by investigating vertical growth, cervical alignment, cervical curvature, and adjacent-segment instability over time. METHODS A total of 15 centers participated in this multi-institutional retrospective study. Cases involving children less than 16 years of age who underwent rigid instrumentation and fusion of the subaxial cervical spine (C-2 and T-1 inclusive) with at least 1 year of clinical and radiographic follow-up were investigated. Charts were reviewed for clinical data. Postoperative and most recent radiographs, CT, and MR images were used to measure vertical growth and assess alignment and stability. RESULTS Eighty-one patients were included in the study, with a mean follow-up of 33 months. Ninety-five percent of patients had complete clinical resolution or significant improvement in symptoms. Postoperative cervical kyphosis was seen in only 4 patients (5%), and none developed a swan-neck deformity, unintended adjacent-level fusion, or instability. Of patients with at least 2 years of follow-up, 62% demonstrated growth across the fusion construct. On average, vertical growth was 79% (4-level constructs), 83% (3-level constructs), or 100% (2-level constructs) of expected growth. When comparing the group with continued vertical growth to the one without growth, there were no statistically significant differences in terms of age, sex, underlying etiology, surgical approach, or number of levels fused. CONCLUSIONS Continued vertical growth of the subaxial spine occurs in nearly two-thirds of children after rigid instrumentation and fusion of the subaxial spine. Failure of continued vertical growth is not associated with the patient's age, sex, underlying etiology, number of levels fused, or surgical approach. Further studies are needed to understand this dichotomy and determine the long-term biomechanical effects of surgery on the growing pediatric cervical spine.

A Modified Technique for Occipitocervical Fusion Using Compressed Iliac Crest Allograft Results in a High Rate of Fusion in the Pediatric Population.

BACKGROUND: In children, high rates of occipitocervical (OC) fusion have been demonstrated with the use of rigid instrumentation in combination with harvested autograft, with or without bone morphogenetic protein (BMP). Historically, the use of allograft materials demonstrated inferior OC fusion outcomes compared with autograft. However, autograft harvest harbors an increased risk of patient morbidity, and the use of BMP is costly and controversial in children. Thus, there remains a need for safer, less costly, yet efficacious techniques for OC fusion in the pediatric population. METHODS: We retrospectively reviewed the charts of patients younger than 21 years of age who underwent OC fusion with structural allograft placement at our institution from 2010 to 2015. Data collected included age, sex, follow-up duration, fusion outcomes, and postoperative complications. RESULTS: A total of 19 patients (8 female and 11 male) underwent OC fusion with our surgical technique. Mean age was 8.5 ± 4.3 years. Radiographic follow up data were available for 18 of 19 patients. One patient was lost to clinical follow up but had radiographic confirmation of fusion. Thus, 18 of 18 (100%) of patients with radiographic follow-up achieved successful arthrodesis as determined by computed tomography. Median duration to documented fusion was 4.5 months. Clinical follow-up was available for 17 of 19 patients and was on average 18.8 ± 13.5 months. One patient required reoperation for graft fracture 8 months after radiographic confirmation of successful fusion. There were no vertebral artery injuries or other postoperative complications. CONCLUSIONS: We demonstrate a modified technique for OC fusion in children with unique structural allograft shaping and affixation, leading to excellent fusion outcomes at follow up. This technique obviates the need for autograft harvest or BMP, and may decrease postoperative morbidity.

Effectiveness of the Dader Method for Pharmaceutical Care on Patients with Bipolar I Disorder: Results from the EMDADER-TAB Study.

BACKGROUND: Bipolar I disorder (BD-I) is a chronic illness characterized by relapses alternating with periods of remission. Pharmacists can contribute to improved health outcomes in these patients through pharmaceutical care in association with a multidisciplinary health team; however, more evidence derived from randomized controlled trials (RCTs) is needed to demonstrate the effect of pharmaceutical care on patients with BD-I. OBJECTIVE: To assess the effectiveness of a pharmaceutical intervention using the Dader Method on patients with BD-I, measured by the decrease in the number of hospitalizations, emergency service consultations, and unscheduled outpatient visits from baseline through 1 year of follow-up. METHODS: This study is based on the EMDADER-TAB trial, which was an RCT designed to compare pharmaceutical care with the usual care given to outpatients with BD-I in a psychiatric clinic. The main outcome was the use of health care services, using Kaplan-Meier methods and Cox regression. The trial protocol was registered in ClinicalTrials.gov (Identifier NCT01750255). RESULTS: 92 patients were included in the EMDADER-TAB study: 43 pharmaceutical care patients (intervention group) and 49 usual care patients (control group). At baseline, no significant differences in demographic and clinical characteristics were found across the 2 groups. After 1 year of follow-up, the risk of hospitalizations and emergencies was higher for the control group than for the intervention group (HR = 9.03, P = 0.042; HR = 3.38, P = 0.034, respectively); however, the risk of unscheduled outpatient visits was higher for the intervention group (HR = 4.18, P = 0.028). There was no "placebo" treatment, and patients in the control group might have produced positive outcomes and reduced the magnitude of differences compared with the intervention group. CONCLUSIONS: Compared with usual care, pharmaceutical care significantly reduced hospitalizations and emergency service consultations by outpatients with BD-I. DISCLOSURES: This study received funding from the Universidad de Antioquia, Committee for Development Research and Sustainability Program, CODI, (2013-2014 and 2014-2015). Humax Pharmaceutical provided support for the initial development of the EMDADER-TAB trial without commercial interest in the outcomes derived from the trial. Salazar-Ospina reports grants from Credito Beca Francisco José de Caldas Scholarship for Doctoral Programs (528), which also contributed to the support of this study. González-Avendaño is an employee of Humax Pharmaceutical. The other authors have nothing to disclose. Study concept and design were contributed by Benjumea, Faus, and Rodriguez, along with Salazar-Ospina and Amariles. Salazar-Ospina took the lead in data collection, assisted by González-Avendaño, and data interpretation was performed by Salazar-Ospina, Hincapié-García, and González-Avendaño. The manuscript was written primarily by Salazar-Ospina, with assistance from Amariles and González-Avendaño, and revised by all the authors.

Urological Outcome of the Xiao Procedure in Children with Myelomeningocele and Lipomyelomeningocele Undergoing Spinal Cord Detethering.

PURPOSE: Although previous studies have revealed high success rates (70% to 85%) after an intradural somatic-to-autonomic nerve transfer procedure in children with spinal dysraphism, no study has had a control group or blinded observers. We report a rigorously designed study to investigate the effectiveness of the Xiao procedure. MATERIALS AND METHODS: Children with neurogenic bladder dysfunction related to myelomeningocele or lipomyelomeningocele who required spinal cord detethering were randomized to 2 groups at surgery, with half undergoing only spinal cord detethering and half undergoing the Xiao procedure in addition to detethering. Double-blind evaluations were performed at regular intervals during the 3-year followup. RESULTS: A total of 10 patients underwent spinal cord detethering only and 10 underwent detethering plus the Xiao procedure. The Xiao procedure did not result in voluntary voiding or continence in any patient, but patients undergoing spinal cord detethering plus the Xiao procedure were more likely to have greater improvements in total bladder capacity, bladder overactivity and overall quality of life than those who underwent detethering only. By the end of the study no participant or evaluator was able to accurately predict to which group the patients had been assigned. CONCLUSIONS: The results of this randomized controlled trial are in agreement with recently published similarly poor results of the Xiao procedure in patients with spinal cord injury. Improvements in bladder parameters observed in this study may be related to sacral nerve root section, a necessary portion of the Xiao procedure, instead of reinnervation. Confirmatory animal studies are recommended before further clinical trials of the Xiao procedure are performed in humans.

Lack of efficacy of an intradural somatic-to-autonomic nerve anastomosis (Xiao procedure) for bladder control in children with myelomeningocele and lipomyelomeningocele: results of a prospective, randomized, double-blind study.

OBJECTIVE Xiao et al. and other investigators have studied an intradural somatic-to-autonomic (e.g., L-5 to S3-4) nerve transfer as a method to create a reflex arc to allow bladder emptying in response to cutaneous stimulation (the Xiao procedure). In previous clinical studies of patients with spinal dysraphism who underwent the Xiao procedure, high success rates (70%-85%) were reported for the establishment of a "skin-CNS-bladder" reflex arc that allows spontaneous, controlled voiding in children with neurogenic bladder dysfunction. However, many of these studies did not use blinded observers, did not have control groups, and/or featured only limited follow-up durations. METHODS A randomized, prospective, double-blind trial was initiated in March 2009, enrolling children with myelomeningocele (MM), lipomyelomeningocele (LMM), and neurogenic bladder dysfunction who were scheduled for spinal cord detethering (DT) for the usual indications. At the time of DT, patients were randomized between 2 arms of the study: half of the patients underwent a standard spinal cord DT procedure alone (DT group) and half underwent DT as well as the Xiao procedure (DT+X group). Patients, families, and study investigators, all of whom were blinded to the surgical details, analyzed the patients' strength, sensory function, mobility, voiding, and urodynamic bladder function before surgery and at regular intervals during the 3-year follow-up. RESULTS Twenty patients were enrolled in the study: 10 underwent only DT and the other 10 underwent DT+X. The addition of the Xiao procedure to spinal cord DT resulted in longer operative times (p = 0.024) and a greater chance of wound infection (p = 0.03). Patients in both treatment arms could intermittently void or dribble small amounts of urine (< 20% total bladder capacity) in response to scratching in dermatomes T-9 through S-2 using a standardized protocol, but the voiding was not reproducible and the volume voided was not clinically useful in any patient. Voiding in response to scratching was not more frequent in patients who underwent DT+X compared with those who underwent only DT. Bladder contractions in response to scratching occurred in both treatment arms at various intervals after surgery, but they were not more reproducible or more frequent in the patients who underwent the Xiao procedure than in the patients who did not. No patient in either treatment arm was continent of urine before, during, or after the study. CONCLUSIONS Patients with MM and LMM who underwent the Xiao procedure during spinal cord DT were no more likely to be able to void, to control their urination, to achieve continence, or to have a demonstrable urodynamic bladder contraction in response to cutaneous stimulation than patients who underwent only spinal cord DT. This study, in the context of disappointing results reported in other recent studies of the Xiao procedure, raises doubts about the clinical applicability of this procedure in humans until further basic science research is performed.

Microbial community modeling using reliability theory.

Linking microbial community composition with the corresponding ecosystem functions remains challenging. Because microbial communities can differ in their functional responses, this knowledge gap limits ecosystem assessment, design and management. To develop models that explicitly incorporate microbial populations and guide efforts to characterize their functional differences, we propose a novel approach derived from reliability engineering. This reliability modeling approach is illustrated here using a microbial ecology dataset from denitrifying bioreactors. Reliability modeling is well-suited for analyzing the stability of complex networks composed of many microbial populations. It could also be applied to evaluate the redundancy within a particular biochemical pathway in a microbial community. Reliability modeling allows characterization of the system's resilience and identification of failure-prone functional groups or biochemical steps, which can then be targeted for monitoring or enhancement. The reliability engineering approach provides a new perspective for unraveling the interactions between microbial community diversity, functional redundancy and ecosystem services, as well as practical tools for the design and management of engineered ecosystems.

Allograft versus autograft for pediatric posterior cervical and occipito-cervical fusion: a systematic review of factors affecting fusion rates.

OBJECT Fusion rates are high for children undergoing posterior cervical fusion (PCF) and occipito-cervical fusion (OCF). Autologous bone has been widely used as the graft material of choice, despite the risk of donor-site morbidity associated with harvesting the bone, possibly because very low fusion rates were reported with posterior allograft cervical fusions in children several decades ago. Higher overall fusion rates using allograft in adults, associated with improvements in internal fixation techniques and the availability of osteoinductive substances such as bone morphogenetic protein (BMP), have led to heightened enthusiasm for the use of bank bone during pediatric PCF. A systematic review was performed to study factors associated with successful bone fusion, including the type of bone graft used. METHODS The authors performed a comprehensive PubMed search of English-language articles pertaining to PCF and OCF in patients less than 18 years old. Of the 561 abstracts selected, 148 articles were reviewed, resulting in 60 articles that had sufficient detail to be included in the analysis. A meta-regression analysis was performed to determine if and how age, fusion technique, levels fused, fusion substrate, BMP use, postoperative bracing, and radiographic fusion criteria were related to the pooled prevalence estimates. A systematic review of the literature was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. RESULTS A total of 604 patients met the specific inclusion and exclusion criteria. The overall fusion rate was 93%, with a mean age of 9.3 years and mean follow-up of 38.7 months. A total of 539 patients had fusion with autograft (94% fusion rate) and 65 patients with allograft (80% fusion rate). Multivariate meta-regression analysis showed that higher fusion rates were associated with OCF compared with fusions that excluded the occiput (p < 0.001), with the use of autograft instead of allograft (p < 0.001), and with the use of CT to define fusion instead of plain radiography alone. The type of internal fixation, the use of BMP, patient age, and the duration of follow-up were not found to be associated with fusion rates in the multivariate analysis. CONCLUSIONS Fusion rates for PCF are high, with higher rates of fusion seen when autograft is used as the bone substrate and when the occiput is included in the fusion construct. Further study of the use of allograft as a viable alternative to autograft bone fusion is warranted because limited data are available regarding the use of allograft in combination with more rigid internal fixation techniques and osteoinductive substances, both of which may enhance fusion rates with allograft.

Accidental intracranial infusion of parenteral nutrition in a preterm neonate.

Vascular access in the neonate can be challenging, especially in preterm infants. When other access is not available, superficial scalp veins can be safely used for vascular access. However, rare and potentially catastrophic complications can occur due to unique features of the neonatal skull and soft-tissue anatomy. The authors report a rare complication of vascular access in a preterm infant, which led to the direct infusion of parenteral nutrition into the intracranial space. The child had an excellent outcome after open drainage and irrigation of bilateral intracranial spaces and the spinal thecal sac. Relevant anatomy is illustrated, and an outcome-based literature review is presented on this rarely reported condition. Surgical and conservative management strategies are discussed, along with clinical and radiographic follow-up. Drainage and irrigation is advocated in patients with mass effect, viscous effusions, or declining neurological examination findings.

Seasonal Patterns in Microbial Community Composition in Denitrifying Bioreactors Treating Subsurface Agricultural Drainage.

Denitrifying bioreactors, consisting of water flow control structures and a woodchip-filled trench, are a promising approach for removing nitrate from agricultural subsurface or tile drainage systems. To better understand the seasonal dynamics and the ecological drivers of the microbial communities responsible for denitrification in these bioreactors, we employed microbial community "fingerprinting" techniques in a time-series examination of three denitrifying bioreactors over 2 years, looking at bacteria, fungi, and the denitrifier functional group responsible for the final step of complete denitrification. Our analysis revealed that microbial community composition responds to depth and seasonal variation in moisture content and inundation of the bioreactor media, as well as temperature. Using a geostatistical analysis approach, we observed recurring temporal patterns in bacterial and denitrifying bacterial community composition in these bioreactors, consistent with annual cycling. The fungal communities were more stable, having longer temporal autocorrelations, and did not show significant annual cycling. These results suggest a recurring seasonal cycle in the denitrifying bioreactor microbial community, likely due to seasonal variation in moisture content.