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Craniofacial and orthognathic surgery are high risk procedures for surgical blood loss. Significant blood loss leads to increased rates of blood product transfusion which may be associated with increased morbidity to the patient. The use of anti-fibrinolytics such as tranexamic acid has become popular in these procedures. However, the evidence to support its use in pediatric craniofacial and orthognathic surgery is sparse. This review analyzes the current randomized control trials assessing the use of tranexamic acid in craniofacial and orthognathic surgery. The study reviewed published literature up until December 20th, 2020. Six trials were included in this analysis. Pooled data showed that patients who received tranexamic acid during craniofacial or orthognathic surgery have less blood loss compared to those in control groups (mean difference—5.47 ml/kg [CI -7.02-3.82], P value

A question that remains unanswered is at what level of surgical correction does the public perceive a head shape to be "normal" or "acceptable?" For most cases of non-syndromic asymptomatic craniosynostosis, the parents desire for surgical correction is to improve the cosmetic appearance of head shape. At the time of this writing, the intraoperative surgeons' perspective of what constitutes an acceptable head shape is the target for surgical correction. In introducing an improved objectively cosmetic goal, an appropriate outcome measure would be to assess what the general public considers a normal or acceptable head shape in children with craniosynostosis. Method Twenty-two unique images were presented via an online crowdsourcing survey of a severe case of non-syndromic sagittal craniosynosis gradually corrected to an age and gender matched normalized head shape. Participants were recruited via the Sick Kids Twitter account. Participants were invited to rate the head shapes as "normal" or "abnormal." Results The 538 participants completed the online survey. Participants were able to reliably and consistently identify normal and abnormal head shapes with a Kappa Score >0.775. Furthermore, participants indicated that a correction of 70% is required in order for the cranial deformity to be regarded as "normal." This threshold closely reflects a normal Cranial Index, which is a widely used morphometric outcome in craniosynostosis. Conclusion Crowdsourcing provides an ideal method for capturing the general population's perspective on what constitutes a normal and acceptable head shape in children with sagittal craniosynostosis. Laypersons are able to reliably and consistently distinguish cranial deformities from a "normal" head shape. The public indicates a threshold correction of 70% in sagittal craniosynosis to regard it as a "normal" head shape.

Auriculocondylar syndrome (ACS) is a rare craniofacial disorder characterized by mandibular hypoplasia and an auricular defect at the junction between the lobe and helix, known as a “Question Mark Ear” (QME). Several additional features, originating from the first and second branchial arches and other tissues, have also been reported. ACS is genetically heterogeneous with autosomal dominant and recessive modes of inheritance. The mutations identified to date are presumed to dysregulate the endothelin 1 signaling pathway. Here we describe 14 novel cases and reassess 25 published cases of ACS through a questionnaire for systematic data collection. All patients harbor mutation(s) in PLCB4, GNAI3, or EDN1. This series of patients contributes to the characterization of additional features occasionally associated with ACS such as respiratory, costal, neurodevelopmental, and genital anomalies, and provides management and monitoring recommendations.

Background Minor cranial sutural synostosis is currently regarded as a rare diagnosis. As clinical awareness grows, a greater number of cases are being documented. This study aims to describe the variants of unicoronal synostosis with regard to major and minor sutural involvement and secondary effects on cranial and orbital morphology. The information is aimed to improve clinical diagnosis and management. Methods A retrospective study was conducted collecting preoperative computed tomographic scans of patients diagnosed with unicoronal synostosis and listed for surgical interventions, identified from a craniofacial database. Within these patients, different synostotic variants were identified based on which suture was affected. Scans of normal pediatric skulls (trauma) were used for a control group. Computed tomographic scans were analyzed for sutural involvement, cranial base deflection, and ipsilateral and contralateral orbital height and width. One-way analysis of variance was used to detect differences between synostotic variants and controls. Results A total of 57 preoperative computed tomographic scans of patients with unicoronal synostosis were reviewed, in addition to 18 computed tomographic scans of normal skulls (control group). Four variants of unicoronal synostosis were identified: frontoparietal, frontosphenoidal, frontoparietal and frontosphenoidal, and frontosphenoidal and frontoparietal. The last two variants differ in their temporal involvement in the direction of sutural synostosis and ultimately cranial and orbital morphology. Three variants have been previously identified, but the fourth is presented for the first time. Conclusions An understanding of the variants of unicoronal synostosis and their temporal relationships is integral for accurate clinical diagnosis and surgical correction. Recommendations for treatment are based on discrete changes in orbital morphology.

In this study, the Potential theory-based Manes method was used to describe competitive multicomponent adsorption of VOC and water vapor onto activated carbon. The thermodynamically consistent method was extended to water-miscible VOCs using a Raoult’s law-like relation. The method uses as input the pure single-component adsorption isotherms, which were obtained from the modified Dubinin-Radushkevich (MDR) model for VOCs and the Qi-Hay-Rood (QHR) model for water vapor. The MDR model was applicable for the studied VOCs (2-propanol, acetone, n-butanol, toluene, 1,2,4-trimethylbenzene) with an overall r2 value of 0.998. The QHR isotherm provided a good description for water vapor adsorption on activated carbon with 0.999 r2 value. Experimental validation tests revealed that the multicomponent adsorption isotherm model predicted the VOC adsorption capacity during competitive adsorption with water vapor with an overall mean relative absolute error (MRAE) of 1.9% for non-polar VOCs and 5.2% for polar VOCs. These results are encouraging, as they indicate a good agreement between modeled and experimental results. Hence, the model can potentially be integrated with dynamic adsorption models to optimize adsorber design and operation or model adsorption kinetics.

Sagittal craniosynostosis is the most common form of congenital cranial deformity. Surgical interventions are performed either open or endoscopic. Advancements in minimally invasive surgery have enabled the development of the endoscopic suturectomy technique. This is contrasted to the traditional open cranial vault reconstruction. There is a paucity of data comparing the head shape changes from both techniques. This study aims to compare the morphological outcome of endoscopic suturectomy versus total cranial vault reconstruction. Methods This is a retrospective comparative study involving 55 cases of sagittal craniosynostosis, 37 of which has open total cranial vault reconstruction and 18 had endoscopic suturectomy procedure. Preoperative and postoperative 3D photographs of both groups were analyzed and compared. The change in correction between preoperative and postoperative state was measured against a crowd-driven standard for acceptable head shape. Results Total cranial vault had higher percentage change between pre and postoperative cranial index than endoscopic suturectomy (14.7% versus 7.7%, P = 0.003). However, both techniques were able to achieve the minimum standard of 70% correction (TCV 107.5%, ES 100.4%, P = 0.02). Conclusion Total cranial vault and endoscopic suturectomy are effective in correcting scaphocephaly among children with sagittal craniosynostosis. Additionally, both techniques are able to achieve a percentage correction that exceeds the 70% benchmark established by the lay public.

A two-dimensional heterogeneous mathematical model was developed and validated to study the effect of relative humidity on volatile organic compound (VOC) adsorption onto activated carbon. The dynamic adsorption model consists of the macroscopic mass, momentum, and energy conservation equations and includes a multicomponent adsorption isotherm to predict the competitive adsorption equilibria between VOC and water vapor, which is described by an extended Manes method. Experimental verifications show that the model predicted the breakthrough profiles during competitive adsorption of the studied VOCs (2-propanol, acetone, n-butanol, toluene, 1,2,4-trimethylbenzene) at relative humidity range 0-95% with an overall mean relative absolute error (MRAE) of 11.8% for dry (0% RH) conditions and 17.2% for humid (55 and 95% RH) conditions, and normalized root-mean-square error (NRMSE) of 5.5 and 8.4% for dry and humid conditions, respectively. Sensitivity analysis was also conducted to test the robustness of the model in accounting for the impact of relative humidity on VOC adsorption by varying the adsorption temperature. Good agreement was observed between the experimental and simulated results with an overall MRAE of 12.4 and 7.1% for the breakthrough profiles and adsorption capacity, respectively. The model can be used to quantify the impact of carrier gas relative humidity during adsorption of contaminants from gas streams, which is useful when optimizing adsorber design and operating conditions.

Heel formation during cyclic adsorption/regeneration of volatile organic compounds (VOCs) on activated carbon decreases its adsorption capacity and lifetime. The effect of regeneration purge gas oxygen content on activated carbon performance, specifically during successive adsorption/regeneration cycles was investigated. 5-cycle adsorption/regeneration tests were performed on a microporous activated carbon using 1,2,4-trimethylbenzene (TMB) as adsorbate. Nitrogen with different oxygen concentrations (≤5, 208, 625, 1250, 2500, 5000, 10,000, and 20,000 ppmv) was used as regeneration purge gas during thermal desorption of TMB (at 288 °C). Cumulative heel formation increased from 0.5% to 15.8% as the oxygen concentration in the desorption purge gas increased from ≤5 to 20,000 ppmv. Thermogravimetric analysis of the regenerated samples showed extensive chemisorption of TMB when exposed to ≥625 ppmv oxygen in the purge gas. The results suggest that regeneration purge gas oxygen impurity can increase heel formation, resulting in lower regeneration efficiency and shorter adsorbent lifetime. The results from this study help explain the heel formation mechanism and how it is related to regeneration purge gas purity.

CAD-CAM patient-specific implants offer cerebral protection and improved facial balance without the disadvantages of autologous bone grafting such as donor site morbidity and unpredictable resorption. Several alloplastic materials are available, but titanium, polymethylmethacrylate (PMMA), and polyetheretherketone (PEEK) are the current popular choices. We reviewed our experience of applying different alloplastic CAD-CAM materials in the reconstruction of complex pediatric craniofacial deformities.A retrospective review was performed of all pediatric patients who underwent a complex inlay or onlay implant craniofacial reconstruction using CAD-CAM PEEK, PMMA, or titanium implants at a single institution. Demographics, cost, operative time, complications, and outcomes were assessed.Between 2003 and 2014, 136 patients (69 male; 67 female; mean age 11.5 years (3-22 years); mean follow-up 30 months) had custom patient-specific craniofacial reconstruction with PEEK (n = 72), PMMA (n = 42), and titanium (n = 22) implants (inlay = 93; onlay = 43). Indications included congenital anomalies (26.5%), decompressive craniectomies (25.0%), craniofacial syndromes (25.7%), tumor defects (14.0%), and post-trauma (6.6%). Implant cost varied significantly for PEEK ($7703 CAD) and PMMA ($8328 CAD) compared with that for titanium ($11,980 CAD) (p 0.0005). Six patients (4.4%) required surgery due to infection consisting of irrigation and antibiotic administration with successful implant salvage in three patients. All infections occurred in the PEEK group. Five patients (3.7%) ultimately had implants removed due to infection (n = 3), late exposure (titanium; n = 1), or late fracture (PMMA; n = 1).CAD-CAM alloplast reconstruction in the management of complex pediatric craniofacial deformities is effective although expensive. Implant infection does not always require explantation. A reconstruction algorithm is presented.

OBJECTIVEDespite increasing adoption of endoscopic techniques for repair of nonsagittal single-suture craniosynostosis, the efficacy and safety of the procedure relative to established open approaches are unknown. In this systematic review the authors aimed to directly compare open surgical and endoscope-assisted techniques for the treatment of metopic, unilateral coronal, and lambdoid craniosynostosis, with an emphasis on quantitative reported outcomes.METHODSA literature search was performed in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Relevant articles were identified from 3 electronic databases (MEDLINE, EMBASE, and CENTRAL [Cochrane Central Register of Controlled Trials]) from their inception to August 2017. The quality of methodology and bias risk were assessed using the Effective Public Health Practice Project (EPHPP) Quality Assessment Tool for Quantitative Studies.RESULTSOf 316 screened records, 7 studies were included in a qualitative synthesis of the evidence, of which none were eligible for meta-analysis. These reported on 111 unique patients with metopic, 65 with unilateral coronal, and 12 with lambdoid craniosynostosis. For all suture types, 100 (53%) children underwent endoscope-assisted craniosynostosis surgery and 32 (47%) patients underwent open repair. These studies all suggest that blood loss, transfusion rate, operating time, and length of hospital stay were superior for endoscopically treated children. Although potentially comparable or better cosmetic outcomes are reported, the paucity of evidence and considerable variability in outcomes preclude meaningful conclusions.CONCLUSIONSLimited data comparing open and endoscopic treatments for metopic, unilateral coronal, and lambdoid synostosis suggest a benefit for endoscopic techniques with respect to blood loss, transfusion, length of stay, and operating time. This report highlights shortcomings in evidence and gaps in knowledge regarding endoscopic repair of nonsagittal single-suture craniosynostosis, emphasizing the need for further matched-control studies.

Introduction: Children with single suture craniosynostosis (SSC) are at risk for neurocognitive problems. The reported magnitude of differences between children with SSC and their normative peers on standardized tests of academic and intellectual ability are small. Evaluation of real-world academic outcomes of these children and its impact on educational resources have not been conducted. Methods: A retrospective cohort study of academic outcomes of children with SSC was conducted using the data from Ontario's Education Quality and Accountability Office (EQAO) standardized provincial reading, writing and mathematics tests. The need for special education was identified by documentation of the child's need for an Identification, Placement, and Review Committee (IPRC). Results: Of 296 eligible children, 42 participated in the study. Half of the children had sagittal synostosis, while the remaining were 10 (24%) unicoronal, 9 (21%) metopic, and 2 (5%) lambdoid synostosis. Thirty-six (86%) underwent operative management. The EQAO scores of operated children with SSC met the provincial academic standards on the Grade 3 and 6 EQAO scores across the 3 academic subjects. Converted grade-matched EQAO scores decreased in reading and writing over time, while math improved. Of the 21 patients with special education data, one child required an IPRC in Grade 3, while an additional four (24%) required an IPRC in Grade 6. Conclusions: Operated children with SSC had average academic performance, however, their needs appeared to change over time. Future studies are needed to evaluate academic difficulties and special education needs as these children progress through grade school.

In syndromic craniosynostosis, the Le Fort III osteotomy is used to correct dental/skeletal imbalance, improve exorbitism, and increase the airway. The purpose of this study is to perform a cost comparison between the standard technique of single-stage rigid internal fixation and distraction osteogenesis (DO) in the Le Fort III osteotomy in this patient population.Hospital cost accounting databases were queried for patients undergoing single-stage advancement (SS) or DO from 2007 to 2016. Nominal cost data were adjusted using the Bank of Canada Consumer Price Index. Reported costs represented the full length of stay for all utilization per patient. Demographic information and cost data for single-stage osteotomy and DO were compared.Total costs for single-stage (n = 8) were higher than distraction (n = 6; mean $CAD57 825 vs $38 268,This single-institution retrospective cost analysis indicates standard SS rigid internal fixation Le Fort III is more costly than DO. Despite higher OR costs, prolonged ICU and hospital stay was the primary reason behind this difference. This information may be of benefit when advocating for new technology perceived as high cost.En cas de craniosynostose syndromique, l’ostéotomie de Le Fort III permet de corriger un déséquilibre dentaire et squelettique, d’améliorer l’exophtalmie et de mieux ouvrir les voies respiratoires. La présente étude vise à comparer les coûts de la technique standard de fixation interne rigide en une étape à la distraction osseuse (DO) au sein de la population de patients en cas d’ostéotomie de Le Fort III.Les chercheurs ont fouillé les bases de données comptables des coûts hospitaliers pour les patients qui avaient subi un avancement en une étape (AUÉ) ou une DO entre 2007 et 2016. Ils ont rajusté les données sur les coûts nominaux à l’aide de l’indice des prix à la consommation de la Banque du Canada. Les coûts déclarés représentaient la durée totale de tous les séjours hospitaliers par patient. Ils ont comparé l’information démographique et les données sur les coûts de l’ostéotomie en une étape à la DO.Les coûts totaux de l'AUÉ (n = 8) étaient plus élevés que ceux de la DO (n = 6) (moyenne de 57 825 $ CA par rapport à 38 268 $,D’après la présente analyse rétrospective des coûts dans un seul établissement, la fixation interne rigide de l’AUÉ standard de Le Fort III est plus coûteuse que la DO. Malgré des coûts plus élevés en salle opératoire, un séjour prolongé à l’USI et à l’hôpital est la principale raison de cette différence. Cette information peut être utile pour défendre les nouvelles technologies qui sont perçues comme coûteuses.

Oxygen’s presence during thermal desorption of volatile organic compounds from activated carbon can promote heel build-up and loss of adsorption capacity. This study investigated the simultaneous effect of desorption temperature (200 °C and 288 °C) and oxygen concentration (≤5, 10,000, and 21,000 ppmv) on heel build-up. For this purpose, 5-cycle adsorption/desorption tests of 1,2,4-trimethylbenzene on a microporous activated carbon were completed. At low oxygen concentration (≤5 ppmv), desorption at 288 °C resulted in lower cumulative heel compared to at 200 °C; however, at high oxygen concentration (10,000 and 21,000 ppmv), desorption at 288 °C resulted in higher cumulative heel compared to 200 °C. Thermal gravimetric analysis (TGA) was used to assess the thermal stability of the heels formed on the samples. At high oxygen concentrations, the heel associated with desorption at 288 °C was more thermally stable than the heel formed at 200 °C, which can be attributed to thermal oxidation reactions of the adsorbate in the activated carbon pores.

This research investigates the effect of adsorbent bed configuration on volatile organic compounds (VOCs) adsorption with beaded activated carbon (BAC). Five-cycle adsorption/desorption tests using a single VOC (1,2,4-trimethylbenzene) and a mixture of nine VOCs were completed using fixed and fluidized bed adsorber configurations. Adsorption tests were completed with full loading of the adsorbent. All regeneration tests were completed in the fixed bed arrangement. The adsorption capacity of the BAC was not affected by the adsorption bed’s configuration in case of reaching full breakthrough. For the VOC mixture, however, 30% less heel buildup was observed for the fluidized bed configuration. Higher accumulation of heavy adsorbates was found in fixed bed as opposed to fluidized bed, explaining the higher heel buildup in the former. On the other hand, improved mass transfer was found across the entire fluidized bed as a result of better gas-particle contact. These results show that, besides the expected engi...

The objective of this study is to determine the contribution of surface oxygen groups to irreversible adsorption (aka heel formation) during cyclic adsorption/regeneration of organic vapors commonly found in industrial systems, including vehicle-painting operations. For this purpose, three chemically modified activated carbon samples, including two oxygen-deficient (hydrogen-treated and heat-treated) and one oxygen-rich sample (nitric acid-treated) were prepared. The samples were tested for 5 adsorption/regeneration cycles using a mixture of nine organic compounds. For the different samples, mass balance cumulative heel was 14 and 20% higher for oxygen functionalized and hydrogen-treated samples, respectively, relative to heat-treated sample. Thermal analysis results showed heel formation due to physisorption for the oxygen-deficient samples, and weakened physisorption combined with chemisorption for the oxygen-rich sample. Chemisorption was attributed to consumption of surface oxygen groups by adsorbed species, resulting in formation of high boiling point oxidation byproducts or bonding between the adsorbates and the surface groups. Pore size distributions indicated that different pore sizes contributed to heel formation - narrow micropores (

The effect of activated carbon's pore size distribution (PSD) on heel formation during adsorption of organic vapors was investigated. Five commercially available beaded activated carbons (BAC) with varying PSDs (30-88% microporous) were investigated. Virgin samples had similar elemental compositions but different PSDs, which allowed for isolating the contribution of carbon's microporosity to heel formation. Heel formation was linearly correlated (R(2)=0.91) with BAC micropore volume; heel for the BAC with the lowest micropore volume was 20% lower than the BAC with the highest micropore volume. Meanwhile, first cycle adsorption capacities and breakthrough times correlated linearly (R(2)=0.87 and 0.93, respectively) with BAC total pore volume. Micropore volume reduction for all BACs confirmed that heel accumulation takes place in the highest energy pores. Overall, these results show that a greater portion of adsorbed species are converted into heel on highly microporous adsorbents due to higher share of high energy adsorption sites in their structure. This differs from mesoporous adsorbents (low microporosity) in which large pores contribute to adsorption but not to heel formation, resulting in longer adsorbent lifetime. Thus, activated carbon with high adsorption capacity and high mesopore fraction is particularly desirable for organic vapor application involving extended adsorption/regeneration cycling.

The effect of desorption purge gas oxygen content on activated carbon performance, specifically irreversible adsorption, was investigated. Beaded activated carbon (BAC) was tested for 5 adsorption/regeneration cycles using a mixture of nine organic compounds representing industrially-relevant organic groups. Different concentrations of oxygen (≤5–10,000 ppm) were used in the N2 desorption purge gas. With increasing O2 concentration, mass balance cumulative heel increased by up to 35% and the fifth cycle adsorption capacity decreased by up to 55% relative to baseline scenario (≤5 ppm O2 in N2). Derivative thermogravimetric analysis showed heel formation due to physisorption for ≤5 ppm O2 and a combination of physisorption and chemisorption for other samples, indicating that with increasing oxygen concentration, compounds that would be physically adsorbed in highly pure N2, may instead undergo chemical reactions and become chemisorbed. Micropore surface analysis indicated increased diffusion resistance in samples regenerated in ≥625 ppm O2, likely associated with chemisorbed species. BAC samples exposed to 50 successive adsorption/regeneration cycles showed trends consistent with short-term exposure (5 cycles). The results may identify suitable purge gas purity for industrial use and explain the relationship between heel formation and purge gas purity.

The authors performed bilateral malar reconstruction using polyether ether ketone implants in 3 patients with Treacher-Collins syndrome with absent, as opposed to hypoplastic, zygomata. These patient-specific implants were fabricated using computed-aided design software reformatted from three-dimensional bony preoperative computed tomography images. The first time the authors performed this procedure the implant compressed the globe resulting in temporary anisocoria that was quickly recognized intraoperatively. The implant was immediately removed and the patient made a full-recovery with no ocular disturbance. The computer-aided design and manufacturing process was adjusted to include periorbital soft-tissue boundaries to aid in contouring the new implants. The same patient, and 2 further patients, subsequently underwent malar reconstruction using this soft tissue periorbital boundary fabrication process with an additional 2 mm relief removed from the implant's orbital surface. These subsequent procedures were performed without complication and with pleasing aesthetic results. The authors describe their experience and the salutary lessons learnt.

This study elucidates the different mechanisms contributing to heel formation during cyclic adsorption–desorption of volatile organic compounds (VOCs) from a painting process in a full-scale adsorber-desorber. Two batches of beaded activated carbon (BAC), one subjected to normal operation and the other inadvertently exposed to oxygen during desorption, were investigated. Both batches displayed sharp increases in apparent density during early cycles, which indicate high heel formation due to occupation/blockage of high-energy adsorption sites. Thermogravimetric analysis and gas chromatography-mass spectrometry results identified non-desorbed adsorbates, adsorbate reaction by-products and char from adsorbate decomposition. The main heel formation mechanisms include physisorption and chemisorption followed by thermal oxidation, pyrolysis and eventually char formation. We hypothesize that non-ideal heat and purge gas distribution across the desorber is the reason for the accumulation of non-desorbed species and heel formation, shortening the lifetime of the adsorbent. In addition to pyrolysis reactions that partially contributed to heel formation in the absence of oxygen, accumulation of thermal oxidation products also contributed to the deterioration of adsorbent performance in the presence of oxygen during desorption. Moreover, extended exposure of the non-desorbed physisorbed and chemisorbed heel species to repetitive desorption cycles ultimately transformed them to permanent (non-desorbable) heel via polymerization and char formation. Therefore, to reduce heel buildup and maximize long-term adsorber performance, it is recommended to (i) ensure effective desorption conditions to prevent or minimize the accumulation of non-desorbed physisorbed species, and (ii) maintain sufficiently low oxygen levels in the desorption purge gas to minimize the detrimental effects of any species that do accumulate.

The adsorption of 1,2,4-trimethylbenzene (TMB) on beaded activated carbon (BAC) in a six-stage countercurrent fluidized bed adsorber was simulated employing a two-phase model, assuming the gas in particulate phase to be either in plug flow (EGPF model) or in perfectly mixed flow (EGPM model). A rather simple model considering equilibrium state on each stage (Equilibrium model) was also used for comparison. Simulation results were compared with experimental data obtained at different values of adsorbent feed rate, superficial gas velocity, TMB initial concentration and weir height (which influences the effective bed height). The results demonstrate that the Equilibrium model overpredicts the overall removal efficiencies when the adsorbate-adsorbent system is far from equilibrium condition. On the other hand, both EGPF and EGPM show good agreement with the experimental results over industrially relevant operating conditions. Stage-wise removal efficiencies show that the EGPF model tends to predict removal efficiency better than EGPM when the weir height is high. The sensitivity analysis of the EGPM model indicates that internal diffusion within the BAC is rate-limiting for adsorption, while BAC diameter strongly influences the overall removal efficiency and can be optimized for different conditions. The effect of changes in BAC adsorption capacity on overall removal efficiency depends on the number of available adsorption sites, as well as proximity to equilibrium condition. The model developed in this study is also able to predict the effect of the number of stages on overall removal efficiency of the adsorber. The results of this study could pave the way for optimizing the design and operation of fluidized bed adsorbers, leading to cost savings and performance improvements.

Introduction: Assessment of cranial dysmorphism in sagittal synostosis is often subjective but objective measures can be applied. These include cephalic index (CI) and midsagittal vector analysis (MSVA). Objective: To assess discriminant validity, construct validity, and responsiveness of CI and MSVA measured from computed tomography (CT) in patients with sagittal synostosis. Methods: Patients with nonsyndromic isolated sagittal synostosis with complete preoperative (n = 30) and postoperative (n = 13) CT data were included. Age-matched control group (n = 24) comprised of normocephalic patients who underwent CT for reasons related to trauma. Outcome Measures: Retrospective CT evaluation of CI and MSVA was conducted and correlated with a dysmorphism numeric rating scale (D-NRS) that measured surgeon-rated severity of sagittal synostosis. Responsiveness of CI and MSVA was evaluated using dysmorphism global rating of change (D-GRC). Results: Thirty patients with sagittal synostosis were demographically similar to 24 normocephalic patients. The difference in CI and MSVA was statistically significant between normocephalic and scaphocephalic patients. Cephalic index had a good correlation with D-NRS ( r = −0.665, ρ = −0.667), but not with MSVA ( r = 0.250, ρ = 0.203). Change in CI ( r = 0.738, ρ = 0.657) was well correlated with D-GRC, but not with MSVA ( r = −0.409, ρ = −0.301). Conclusion: Cephalic index appears to quantify the severity of sagittal synostosis better than MSVA. Cephalic index also has better responsiveness than MSVA to measure a reduction in severity of disease; however, MSVA is a better descriptive craniometric measurement. Midsagittal vector analysis was able to quantify the shift in morphology in sagittal synostosis following surgical treatment.

OBJECTIVEIn this systematic review and meta-analysis the authors aimed to directly compare open surgical and endoscope-assisted techniques for the treatment of sagittal craniosynostosis, focusing on the outcomes of blood loss, transfusion rate, length of stay, operating time, complication rate, cost, and cosmetic outcome.METHODSA literature search was performed in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Relevant articles were identified from 3 electronic databases (MEDLINE, EMBASE, and CENTRAL [Cochrane Central Register of Controlled Trials]) from their inception to August 2017. The quality of methodology and bias risk were assessed using the Effective Public Health Practice Project Quality Assessment Tool for Quantitative Studies. Effect estimates between groups were calculated as standardized mean differences with 95% CIs. Random and fixed effects models were used to estimate the overall effect.RESULTSOf 316 screened records, 10 met the inclusion criteria, of which 3 were included in the meta-analysis. These studies reported on 303 patients treated endoscopically and 385 patients treated with open surgery. Endoscopic surgery was associated with lower estimated blood loss (p < 0.001), shorter length of stay (p < 0.001), and shorter operating time (p < 0.001). From the literature review of the 10 studies, transfusion rates for endoscopic procedures were consistently lower, with significant differences in 4 of 6 studies; the cost was lower, with differences ranging from $11,603 to $31,744 in 3 of 3 studies; and the cosmetic outcomes were equivocal (p > 0.05) in 3 of 3 studies. Finally, endoscopic techniques demonstrated complication rates similar to or lower than those of open surgery in 8 of 8 studies.CONCLUSIONSEndoscopic procedures are associated with lower estimated blood loss, operating time, and days in hospital. Future long-term prospective registries may establish advantages with respect to complications and cost, with equivalent cosmetic outcomes. Larger studies evaluating patient- or parent-reported satisfaction and optimal timing of intervention as well as heterogeneity in outcomes are indicated.

Heel formation on three activated carbon fiber cloths (ACFC10, ACFC15, and ACFC20, with increasing pore widths and volumes) was assessed after cyclic adsorption/resistive heating regeneration using 1,2,4-trimethylbenzene (TMB). Following regeneration at 288 °C, cumulative heel for ACFC10, ACFC15, and ACFC20 was 3.5 wt%, 4.1 wt%, and 4.2 wt%, respectively. Adsorption capacity of ACFC10; however, dropped by 83% compared to only 9% and 5% for ACFC15 and ACFC20, respectively. To prevent these capacity losses, regeneration temperature was increased to 400 °C. However, this increased cumulative heel and adsorption capacity losses to 3.7 wt% and 93% (ACFC10), 10.4 wt% and 51% (ACFC15), and 18.9 wt% and 50% (ACFC20), respectively. It is proposed that these observations results from carbon deposition due to thermal degradation of TMB during regeneration and rapid adsorbent heating. Increasing regeneration temperature enhances the endothermic decomposition processes, increasing heel buildup. Because the pores in ACFC10 are narrower than in ACFC15 and ACFC20, even small amounts of heel obstruct ACFC10's pores, explaining its notably larger decrease in adsorption capacity. These results suggest that rapid heating could be associated with reduced adsorbent performance. Regeneration conditions could be optimized to allow fast desorption with minimal adsorbate decomposition.

Objective To investigate the stability of major versus minor Le Fort I maxillary advancements in unilateral cleft lip and palate (UCLP) patients. Design A retrospective longitudinal study was undertaken on 30 nonsyndromic UCLP patients treated with the same protocol at The Hospital for Sick Children, Toronto, Canada. Patients were grouped into major and minor movement groups based on planned surgical advancement. Standard lateral cephalometric radiographs were taken preoperatively (T1), immediately postoperatively (T2), and at least 1 year postoperatively (T3). Skeletal and dental variables were measured using cephalometric analysis. Stability was compared between groups using repeated-measures analysis of variance. Linear regression analysis was used to assess the relationship between advancement and relapse for the entire study population. Results A mean maxillary advancement of 9.8 mm and 4.9 mm was seen for the major (n = 10) and minor (n = 20) movement groups, respectively. The mean skeletal horizontal relapse was 1.8 mm (18%) for the major advancement group and 1.5 mm (31%) for the minor advancement group. There was no significant difference in skeletal horizontal relapse between the groups ( P > .05). The correlation coefficient ( r) between linear horizontal advancement and relapse was calculated to be .31 ( P > .05). Dental horizontal relapse was not significant for either the major or minor groups, and no significant difference was found between the groups ( P > .05) Conclusion Skeletal and dental relapse was found to be unrelated to the amount of maxillary linear advancement using conventional Le Fort I osteotomies in UCLP.

Purpose To investigate the stability of single-piece versus segmental (2-piece) maxillary advancement in patients with unilateral cleft lip and palate (UCLP) treated using conventional Le Fort I orthognathic surgery. Patients and Methods A retrospective study was undertaken in 30 patients with nonsyndromic UCLP treated with the same surgical and orthodontic protocol from 2002 through 2011. Standard lateral cephalometric radiographs were taken preoperatively, immediately postoperatively, and at least 1 year postoperatively. Patients were divided into single-piece and segmental Le Fort I groups based on planned surgical movement. Postoperative movements were compared between groups using repeated measures analysis of variance. Results The mean skeletal horizontal advancement was 7.3 and 7.5 mm in the single-piece and segmental groups, respectively. The skeletal horizontal relapse was 1.3 mm (18%) for the single-piece group and 1.9 mm (25%) for the segmental group. The skeletal surgical extrusion was 2.7 mm for the 2 groups. The skeletal vertical relapse was 0.6 mm (22%) and 1.5 mm (56%) for the single-piece and segmental groups, respectively. The mean dental horizontal postoperative movement was an advancement of 0.4 mm for the single-piece group and a relapse of 0.2 mm (3%) for the segmental group. The mean dental vertical relapse was 0.1 mm (4%) for the single-piece group and 0.3 mm (11%) for the segmental group. There was no statistically significant difference in relapse between the single-piece and segmental groups for all movements ( P > .05). Conclusion Skeletal and dental relapse was similar between single-piece and segmental maxillary advancements using conventional Le Fort I orthognathic surgery in patients with UCLP.

Cranio-orbital reshaping for anterior cranial-vault deformities associated with craniosynostosis traditionally relies on the surgeon's subjective estimate of the shape and appearance of a normal forehead. Computer-aided design/computer-aided manufacture (CAD/CAM) bandeau templates to guide reconstruction were introduced in our centre to eliminate this subjectivity and to effect more reproducible surgical results. The aim of this study was to compare two groups of patients (template, n = 14 vs. no template, n = 23) to measure surgical outcomes. The virtual, computational version of the template was used as an outcome assessment tool. It was used to calculate an intervening area under the curve (AUC) between the normative template and the patient's reconstructed supra-orbital bar on a representative computed tomography (CT) axial section. A comprehensive chart review was conducted of patients in both groups to examine the preoperative and postoperative variables. Based on the analysis performed on the immediate postoperative CT scans, in the template group - as compared to the control, no-template group - the use of the bandeau template led to a greater reduction in AUC (74% vs. 56%, p = 0.016), indicating a better conformity between the reconstructed supra-orbital bar and the ideal, normal bandeau shape. The duration of operation was significantly reduced with the use of the template (212 vs. 258 min, p0.001). The application of prefabricated templates in cranio-orbital reshaping is highly useful for accurate preoperative planning; reproducible and efficient intra-operative correction of dysmorphology; and objective surgical outcomes assessment.

Predicting outcomes based on a variety of fixation techniques remains problematic in the treatment of mandible fractures. There is inherent difficulty in comparing the hundreds of published articles on the subject because of the large number of variables, including injury patterns, assessment techniques, treatment approach, device selection and application, and definition of outcome.The authors review the behavior of the human mandible. Behavior of the intact mandible, multiple fracture scenarios, and small and large (single and multiple) plating applications are reviewed.Several misconceptions in the literature are clarified. Factors that will resolve the dichotomy between clinical results and current biomechanical theories are presented such that a more logical biomechanical model may be used to approach fixation of the mandibular fracture being treated.Current mandibular biomechanics theory must be expanded to reflect the complex nature of the system and to more accurately describe conditions that exist in the physical world. Otherwise, further analysis in advancements in outcome and treatment will be relegated to chance.

Cranio-orbital remodeling aims to correct the dysmorphic skull associated with craniosynostosis. Traditionally, the skull is reconstructed into a shape that is subjectively normal according to the surgeon's perception. We present a novel technique using a mathematical algorithm to define the optimal location for bony osteotomies and to objectively reshape the fronto-orbital bar into an ideal normal skull contour. Using pre-operative computed tomography images, the abnormal skull contour at the frontal-orbital region was obtained for infants planned to undergo cranio-orbital remodeling. The ideal skull shape was derived from an age- and sex-matched normative skull library. For each patient, the mathematical technique of dynamic programming (DP) was applied to compare the abnormal and ideal skull shapes. The DP algorithm identifies the optimal location of osteotomy sites and calculates the objective difference in surface area remaining between the normative and dysmorphic skull shape for each solution applied. By selecting the optimal solution with minimal objective difference, the surgeon is guided to reproducibly recreate the normal skull contour with defined osteotomies. The DP algorithm was applied in 13 cases of cranio-orbital remodeling. Five female and 8 male infants with a mean age of 11 months were treated for craniosynostosis classified as metopic (n = 7), unicoronal (n = 4), or bicoronal (n = 2). The mean OR time was 190.2 min (SD 33.6), mean estimated blood loss 244 cc (SD 147.6), and 10 infants required blood transfusions. Compared with a historical crania-orbital remodeling group treated without application of the algorithm, there was no significant difference in OR time, estimated blood loss, or transfusion rate. This novel technique enables the craniofacial surgeon to objectively reshape the fronto-orbital bar and reproducibly reconstruct a skull shape resembling that of normal infants.

Summary Introduction Treacher Collins syndrome is a rare disorder characterized by several orofacial findings including malar deficiency and hypoplastic mandibles. These patients often require a combined orthodontic–orthognathic approach to correct their malocclusion. This is most often characterized by a short posterior vertical height and an anterior open bite. Orthognathic correction often requires Le Fort I and bilateral sagittal split osteotomies. No long-term stability results have been reported after bimaxillary surgery in Treacher Collins patients. Methods A retrospective review of all Treacher Collins patients evaluated for orthognathic surgery by a single surgeon from 1993 to 2007 was performed. Patients were divided into groups who required surgery and those who did not. Part I analyzed the cephalometric differences between the surgical (S) and nonsurgical (NS) groups. Part II of the study assessed the preorthodontic treatment ( T 1 ), preoperative ( T 2 ), immediate postoperative ( T 3 ), and 1-year postoperative ( T 4 ) cephalometric measurement variables to determine the net surgical movement ( T 3 − T 2 ) and relapse ( T 4 − T 3 ). Results Twenty-two patients met the inclusion criteria, of which 11 had occlusal relationships requiring orthognathic surgery. Nine out of 11 chose to have surgery. At baseline, surgical patients exhibited a statistically significant retruded maxilla as measured by SNA and midface length compared to the NS group. In addition, the S group also had an increased gonial angle. There were significant movements in all maxillary and mandibular measurements. There was a significant relapse in the palatal plane angle when the maxilla was anteriorly impacted, with a 2.8-mm average relapse of the advancement. Relapse of the counterrotation movement of the mandible was identified, but this was not significant. Relapse did not affect the final occlusal result, which may have been compensated with postsurgical orthodontic treatment. Conclusion Bimaxillary orthognathic surgery in the Treacher Collins patients may be performed safely with long-term dental and skeletal stability.

Incomplete regeneration of activated carbon loaded with organic compounds results in heel build-up that reduces the useful life of the adsorbent. In this study, microwave heating was tested as a regeneration method for beaded activated carbon (BAC) loaded with n-dodecane, a high molecular weight volatile organic compound. Energy consumption and desorption efficiency for microwave-heating regeneration were compared with conductive-heating regeneration. The minimum energy needed to completely regenerate the adsorbent (100% desorption efficiency) using microwave regeneration was 6% of that needed with conductive heating regeneration, owing to more rapid heating rates and lower heat loss. Analyses of adsorbent pore size distribution and surface chemistry confirmed that neither heating method altered the physical/chemical properties of the BAC. Additionally, gas chromatography (with flame ionization detector) confirmed that neither regeneration method detectably altered the adsorbate composition during desorption. By demonstrating improvements in energy consumption and desorption efficiency and showing stable adsorbate and adsorbent properties, this paper suggests that microwave heating is an attractive method for activated carbon regeneration particularly when high-affinity VOC adsorbates are present.

Background: Mandible advancement osteotomy in juvenile rheumatoid arthritis patients for class II anterior open-bite malocclusion is controversial; however, there is no literature discussing outcomes of surgery in this group of patients. An evaluation of such outcomes was undertaken at The Hospital for Sick Children. Methods: A retrospective chart review revealed that eight patients with juvenile arthritis underwent orthognathic surgery during a period of 5 years. All of the patients had a bilateral sagittal split osteotomy of the mandible, six had a simultaneous Le Fort I osteotomy, and four had an additional advancement genioplasty. The age of the patients at the time of surgery ranged between 17 and 22 years (mean, 18 years), with three male patients and five female patients. The patients were under follow-up for a minimum of 8 months after surgery, and measurements were performed studying preoperative and postoperative lateral cephalometric radiographs. Results: All patients have an improved occlusion and improved facial aesthetics. One patient continued to suffer from temporomandibular joint pain. The mean mandible advancement was 9.6 mm (range, 3.9 to 18.3 mm). The mean mandible relapse after surgery was 2.1 mm (range, 1 to 3.1 mm). No exacerbation of the juvenile rheumatoid arthritis was encountered as a result of the surgical procedure. Conclusions: Orthognathic surgery in juvenile rheumatoid arthritis patients improves the patient’s occlusion, facial aesthetics, and therefore quality of life. The relapse rate postoperatively did not significantly affect the clinical outcome, and the authors recommend orthognathic surgery for this patient population. Future presurgical plans in this patient population will include a small posterior open bite and positioning the incisors edge to edge to allow for some postoperative relapse.

Lateral canthopexy is a commonly performed procedure in craniofacial and cosmetic surgery. In craniofacial surgery, lateral canthal fixation is performed in conjunction with a wide range of transcranial or subcranial procedures during the process of soft tissue re-suspension. A number of fixation materials have gained popular use. A case of craniofrontonasal dysplasia is reported in which a wire loop canthopexy fixation has become disengaged 3 months after a history of trauma and rotated to present a sharp surface against the sclera. Urgent surgical exploration prevented the apparently imminent complication of globe penetration with associated threat to vision.

Background: Mandible reconstruction in the growing facial skeleton is challenging, especially with reconstructions necessitating free vascularized bone grafts. The need for further combined orthodontic-orthognathic intervention at skeletal maturity must be anticipated. The growth potential of these grafts and potential new problems associated with performing a sagittal split osteotomy at skeletal maturity are poorly understood. Methods: A retrospective chart review revealed 11 patients who underwent reconstruction with a free fibula at The Hospital for Sick Children from 1990 to 2000. Radiographic and photographic studies were assessed for long-term growth of the reconstructed mandible, with follow-up ranging from 2 to 12 years. Results: Of the 11 patients who underwent reconstruction with a free fibula, two had surgery at skeletal maturity, two moved out of the country, one died as a result of her malignancy, and one was lost to follow-up. The remaining five patients are being followed by the craniofacial and orthodontic services and have not reached skeletal maturity. Of the two patients who have had orthognathic surgery, the one patient whose reconstruction involved the temporomandibular joint exhibited no growth on the reconstructed side and required a 57-mm advancement on the reconstructed side. The other patient, who had preservation of the temporomandibular joint at the time of reconstruction, required only a 5-mm advancement on the reconstructed side. Both patients had significant surgical complications as a result of the initial reconstructive techniques. Technical modifications necessary at the initial reconstruction became apparent when the authors performed a sagittal split osteotomy on the reconstructed side. Conclusions: Certain technical modifications to the original free fibula reconstructed pediatric mandible should be considered in anticipation of the need for a subsequent bilateral sagittal split at skeletal maturity.

The purpose of this study was to appraise the value of preoperative speech assessments, nasopharyngoscopy, and surgical models as predictors of velopharyngeal deterioration after a Le Fort I maxillary advancement in cleft patients. This retrospective study involved a series of 26 cleft patients (16 unilateral complete and nine bilateral complete cleft lips and palates, and one isolated complete cleft palate) who had Le Fort I maxillary advancements between March 1, 1993, and February 7, 1996. The 13 male patients and 13 female patients ranged in age from 15.3 to 46 years (mean age, 19.5 years). Four of these patients had previously undergone pharyngeal flap surgery. Eleven patients had palatal fistulas and one had a bifid uvula that was repaired at the time of orthognathic surgery. Patients with perceived hypernasal speech preoperatively all had hypernasality after advancement (nine of nine). Velopharyngeal insufficiency was observed in two of the 16 whose resonance preoperatively was within normal limits. Speech assessment, therefore, predicted accurately the postoperative status in 23 of 26 patients. Twelve patients had preoperative nasopharyngoscopy that indicated a high risk for velopharyngeal insufficiency (borderline or inadequate closure). Nine of these patients had postoperative velopharyngeal insufficiency. Two of the 14 patients not judged at risk by nasopharyngoscopy developed velopharyngeal insufficiency. Therefore, 21 of the 26 patients were accurately predicted by nasopharyngoscopy. Scoping detected borderline velopharyngeal insufficiency in one patient who was not detected by speech alone. The combined predictive value of speech and scope identified all but one patient who would develop postoperative velopharyngeal insufficiency. The degree of anteroposterior movement determined from surgical models was not predictive of the outcome. Patients with hypernasal speech preoperatively continue to have hypernasal speech after Le Fort I advancement. Preoperative perceptual speech assessment by specially trained speech-language pathologists is an excellent test for predicting postoperative velopharyngeal insufficiency status. Nasopharyngoscopy is an invasive and resource-dependent test that should be assessed with respect to cost effectiveness. In this series, only one patient's risk was more accurately predicted using nasopharyngoscopy than by speech assessment alone.

Due to the rarity of arteriovenous malformations (AVMs), there is a paucity of information on the outcomes of various treatments. Presently, the mainstays of treatment of an AVM are embolization, surgical excision or a combination of both. A retrospective study of 26 patients with AVMs treated at The Hospital for Sick Children, Toronto, Ontario between 1985 and 1995 was performed. The treatment strategies and patient outcomes were compared in terms of efficacy, complications and the response of patients and their families to their overall treatment. The overall findings showed that embolization alone was effective in controlling symptoms, but may be associated with an increased AVM size. A partial excision of an AVM does not appear to exacerbate recurrence, as has been previously reported. In fact, even after what appears to be a complete excision of the AVM, recurrence may still occur. Complications from a surgical excision of the AVM are more frequent but less devastating than complications from embolization of the lesion. The overall patient or parent satisfaction with treatment was high with respect to improvement in outcome. It is expected that with an increasing understanding of vascular malformations, and the evolution of interventional radiological techniques, complications will decrease and results as a whole will improve.Compte tenu de leur rareté, on dispose de peu d’informations sur le résultat des divers traitements appliqués aux malformations artérioveineuses (MAV). À l’heure actuelle, le traitement d’une MAV repose sur l’embolisation, l’excision chirurgicale ou sur les deux approches combinées.Les auteurs ont procédé à une étude rétrospective de 26 cas de MAV traités au

The lack of tip projection on the affected side of a unilateral cleft lip nasal deformity can be difficult to correct due to lack of adequate structural support. A new technique for the correction of the unilateral cleft lip nasal deformity is described. The key components of the technique involve the use of a dorsally angulated unilateral spreader graft on the cleft side and the use of an L-shaped septal graft to provide support to the cleft nasal tip.