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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.

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.

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.

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.

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.

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.

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.

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.

(2001). Room 619 - The Tragedy of Steve Biko. Australian Journal of Forensic Sciences: Vol. 33, No. 1, pp. 3-8.

Morphological characteristics of the "cleft face" were analyzed by calculating proportion indices in young adults who had undergone surgery in childhood for cleft lip and/or palate: 592 in 37 subjects with unilateral clefts and 432 in 27 with bilateral clefts. Three areas of the face with 16 indices based on 12 projective linear measurements were analyzed in each subject: 5 indices in the general face, 6 in the upper face, and 5 in the lower. Although a balanced relationship was found in two thirds of the indices assessed, severe disproportions, which greatly influence appearance, were noted in about one quarter. In the general face, the most frequent abnormal anthropometric findings contributing to severe disproportions were small upper-face height and a severely high or moderately narrow mandible. In the soft tissues, disproportions included wide nose, small nasal tip protrusion, and short or long columella. Deviations from normality were rarely noted in the nose and upper-lip height, mouth width, total facial height, and width of the upper face. In the upper face, severe disproportions occurred much more frequently in bilateral cleft subjects (67.6%) than in unilateral clefts (30.3%). In the lower face, however, severe disproportions were twice as frequent among unilateral clefts (39.4%) than bilateral (14.7%). The results, although interesting, require complementary preoperative data for reliable analysis of the adult "cleft face."

In this study, the authors review their experience with vascularized fibula transfers for mandibular reconstruction in children. They outline the indications for such reconstruction, their method of contouring the fibula to accurately resemble the resected mandible, reconstruction of the temporomandibular joint, and the use of vascularized muscle for the management of associated soft-tissue deficiencies. Ten consecutive patients, 5 to 17 years of age and undergoing this procedure, were assessed from a medical, dental, radiographic, and photographic standpoint. The fibulae were elevated via a lateral approach, osteotomized, as required, and fixation was achieved with titanium miniplates and screws. All transfers survived, with viability confirmed by early postoperative bone scanning. Five patients had temporomandibular joint reconstruction, and five patients required simultaneous reconstruction of soft-tissue defects with associated vascularized muscle. The postoperative follow-up ranged from 3 to 30 months The occlusion of the remaining dentition, mandibular symmetry and projection, adequacy of lining and skin cover, and maximal mouth opening were reassessed. Occlusion was class 1 in all patients, and free-flap stability and function were in the normal range. However, soft-tissue contour was a problem. All wounds healed primarily without donor-site complications and with minimal recipient-site complications.

We have suggested that rigid fixation of membranous bone grafts in the presence of infection may improve graft-recipient bone union by facilitating graft revascularization. To test this hypothesis, we grafted autogenous membranous bone grafts to the mandibles of 94 New Zealand White rabbits. Lag screw fixation was applied in half the animals. The wounds were inoculated with a range of Staphylococcus aureus doses. Infected and noninfected rabbits were injected weekly over a 5-week course with fluorescein bone markers and with a marker of vascular endothelium (procion red) just prior to sacrifice. Revascularization and new bone deposition in the grafts were then quantified histologically for the 75 rabbits available for data collection. Infection decreased the amount of graft revascularized and the amount of new bone deposited for both rigidly fixated and nonfixated grafts. Grafts fixated with a lag screw showed a greater amount of revascularization and new bone deposition in the presence and absence of infection when compared with nonfixated grafts, supporting the hypothesis that rigid fixation of membranous bone grafts in the presence of infection may promote graft survival and union by improving revascularization and osteogenesis within the graft.

Guided tissue regeneration has been shown to permit osteoconduction in otherwise nonhealing cranial defects. The relative importance of preventing the prolapse of soft tissue versus the infiltration of individual connective tissue cells has not been determined. A fibrillar form of polylactic acid (PLA) was tested in 13-mm-diameter defects in the parietal bones of 12 sheep. The polymer was hypothesized to prevent the prolapse of dura and periosteum but allow entrance of individual cells. Control defects in the same sheep were either filled with autogenous bone shavings or left unfilled. The animals were killed at times ranging from 6 to 25 weeks and the defects examined grossly, radiologically, and histologically. The autogenous bone-filled defects were spanned by trabeculated bone by 6 weeks. The unfilled defects demonstrated prolapse of soft tissues into the defect; however, progressive centripetal bone growth was evident. The fibrillar PLA-filled defects were occupied by a full-thickness mixture of fibrous tissue interspersed with PLA. After 19 weeks, small "fingers" of bone were seen to minimally infiltrate the fibrous tissue. Although separation of the dura and periosteum was maintained by the fibrillar PLA, invasion of fibrous tissue restricted osteoconduction.

After studying this article, the participant should be able to: 1. Identify the skeletal changes in the cleft patient that necessitate surgery. 2. Describe the orthodontic principles that precede surgical treatment. 3. Demonstrate the surgical principles involved in cleft orthognathic surgery and how to avoid common pitfalls particular to cleft orthognathic surgery. 4. Anticipate when dentoalveolar distraction can help in the treatment of problems not easily treated with conventional orthognathic techniques.This CME article covers the basic multidisciplinary approach to the treatment of patients requiring a combined orthodontic orthognathic approach to their skeletally based malocclusion. The dentoskeletal abnormalities are described for these patients, as are the fundamental orthodontic principles in the presurgical treatment of these patients. The basic surgical principles are discussed in general, and the reader is provided with advice on avoiding common pitfalls. Specific attention is given to the more recent advances in dentoalveolar distraction in cases of large defects that would have been difficult to treat using conventional orthognathic surgery. Videos are provided to illustrate the general principles in treating the cleft orthognathic patient and to illustrate the treatment of large defects using dentoalveolar distraction.

A nickel-catalyzed cycloisomerization coupling an allylic alcohol with an alkyne has been developed. Mechanistic insights gained through deuterium-labeling crossover studies and stereochemical probes illustrate that oxidation of the allylic alcohol to a metal-free enone is not involved in the cyclization pathway. The intermediacy of a metallacycle directly derived from oxidative cyclization of Ni(0) with the allylic alcohol and alkyne is consistent with the results obtained. The simple mechanistic probes employed could be useful in the study of many classes of cycloisomerization processes.

A stereotactic system has been designed to address the problem of achieving symmetry in complex and extensive craniofacial defects. Preliminary testing suggests that such a system, which allows for the intraoperative application of preoperative CT planning, will be useful in guiding the reconstruction of congenital or acquired bony time, is being used to investigate the correlation of intraoperative globe position following enophthalmos correction with long-term outcome, particularly as it relates to the size and location of the orbital defect, and the timing of the procedure.

A significant release of catecholamines within the heart has been observed during myocardial ischemia. Because this can be markedly inhibited by amine-uptake-blocking agents, it has been suggested that its mechanism is a carrier-mediated efflux from neurons, which is not operative under normal conditions. The present work examined this release process in chromaffin cells isolated from the bovine adrenal medulla, a model system for studying the sympathetic nervous system. Chromaffin cells in primary culture retained normal secretory responses for up to 7 days. Conditions designed to mimic ischemia, that is, anoxia or metabolic inhibition, resulted in a significant release of catecholamines. This release was shown to be independent of extracellular calcium but, in contrast to the release observed in ischemic hearts, was not inhibited by amine-uptake blockers. Electrophoresis with immunoblotting demonstrated that significant levels of the chromaffin granule protein, chromogranin A, were released during metabolic inhibition, indicative of an exocytotic mechanism. However, there was no release of the cytosolic protein, lactate dehydrogenase, indicating that there was no concomitant breakdown of the cell membrane. These results provide evidence for an exocytotic release of catecholamines mediated by the direct action of conditions of metabolic inhibition.

Following craniofacial procedures that involve stripping of the periosteum and soft tissue over the zygomatic maxillary complex, descent of soft tissue with a decrease in anterior projection over the malar area and increase in fullness in the nasolabial fold have been seen to be a problem by these authors. Simple repositioning of the soft tissues to their normal anatomic position may be used to alleviate this problem.

An exchange hydrogenation reaction on trioxsalen yields two isomeric dihydro analogues for which a combined HPLC-supercritical fluid chromatography method supplies purified materials. These reduced compounds and a related benzodipyranone are biologically active and inhibit the binding of epidermal growth factor on HeLa cells to an even greater extent than trioxsalen. This observation suggests a non-DNA target may play a role in the overall effects of psoralens on cells.

The authors report on their experience with a particular hydroxyapatite cement in the pediatric population and review cases that elucidate potential limitations of its use in this population. In all patients, the implant was used for recontouring and augmenting the cranial vault. Seven of 15 patients had a direct communication between sinus mucosa and the implant at the time of surgery. Three of the seven patients developed late postoperative inflammatory reactions of the surgical site with delamination of the implant. Each patient required an aggressive irrigation and debridement with removal of the delaminated hydroxyapatite. Pathologic findings showed evidence of a foreign body inflammatory reaction in the tissue, and mixed bacterial flora were identified in all specimens. No late problems with the cement were seen in patients without a communication to the sinuses. Our findings suggest that the use of BoneSource, an essentially nonviable, nonvascularized implant, in areas exposed to bacterial contamination is contraindicated in the pediatric population. BoneSource and other similar hydroxyapatite biomaterials do have a role as implants in the craniofacial skeleton. The indications and contraindications of these substances will need to be further defined for wide acceptance to occur.

The potential use of distraction osteogenesis in mandibular reconstruction has been limited by its questionable efficacy in previously radiated bone. We studied five mongrel dogs that had a hemimandible rendered edentulous and underwent a full course of external beam radiation therapy (50 Gy/20 fractions). Six months after completion of radiotherapy, a 2-cm critical-size segmental mandibular defect was created and stabilized with a stainless steel plate. A proximal mandibular transport segment was then formed and an external lengthening apparatus (Orthofix) applied. By means of bifocal distraction osteogenesis, the defects were filled with new bone in a period of 30 days in four of five dogs. Histologic analysis and fluorochrome microscopy confirmed the formation of new cortical bone. Our results suggest that distraction osteogenesis is successful in previously radiated bone and that it may be a simple method of mandibular reconstruction following ablative head and neck surgery.

In chromaffin granule ghosts, the Na+/Ca2+ exchanger in the granule membrane can provide a high affinity (Km 1-3 microM) and high capacity (Vmax 50-100 nmol mg min-2) mechanism for Ca2+ accumulation. The activity of the Na+/H+ antiporter can be used to couple Ca2+ uptake via Na+/Ca2+ exchange to ATP-dependent proton translocation via the granule membrane H(+)-ATPase. Therefore, Ca2+ uptake can be indirectly linked to the proton pump. However, under conditions designed to mimic the environment of a granule in the cytosol of a chromaffin cell, measured rates of Ca2+ uptake are low, a free Ca2+ concentration of about 5 microM in the ghost matrix being attained. Under such circumstances, the granules seem unlikely to play a major role in calcium homeostasis in the intact cell.

The pronounced variability of the cranial base angle and the degree of maxillary hypoplasia in Crouzon patients is well established in the literature. However, the correlation between these two variables has not been studied previously in Crouzon patients who have not undergone surgery. We studied the nasion-sella-basion and sella-nasion-subspinale (SNA) angles in 16 patients with Crouzon's syndrome, but who had not undergone surgery, and found that such a correlation does not exist. Patients with basilar kyphosis and lordosis manifested variable degrees of maxillary hypoplasia. Furthermore, normal skull base angle in Crouzon patients was not associated with normal SNA angle.

Thirty-five AIDS patients (mean CD4 count 44 x 10(6)/L) with chronic cryptosporidiosis were treated with letrazuril at an initial oral daily dose of 50 mg in an open-label Phase I prospective trial. Treatment was continued for > or = 10 days and for as long as there was a response. The majority of subjects (91%), had previously failed paromomycin treatment. At baseline, 74% of patients had moderate (five to nine bowel movements per day) to severe (> 10 bowel movements per day) diarrhea. Twenty-three subjects (66%) had a clinical response within a mean of 1.7 weeks of treatment initiation. Twenty-two patients had a partial response (> 50% reduction in bowel movements per day for > or = 1 week), one patient had a complete response (two or fewer bowel movements per day). Of the responders, 15 (65%) had a clinical relapse with worsening diarrhea at an average of 1.2 months following initiation of letrazuril. The other eight (35%) had had symptom control for an average of 2.9 months from initiation of letrazuril to the latest follow-up. Microbiologic eradication was demonstrated in 10 (40%) of 25 patients with follow-up stool examinations. Seven patients (20%) experienced a rash, all within 1 week of starting the drug, and resolved in all patients when the drug was discontinued. In conclusion, severely immunocompromised AIDS patients with refractory cryptosporidiosis may show a modest, short-lived response to letrazuril. Microbiologic response is variable and relapse high. Rash is a major limiting side effect of the drug.

Municipal sewage sludges were characterized for a group of phenols classified as priority pollutants. The development of analytical methodology, including unique problems encountered when sampling, handling and analyzing phenolic compounds, are discussed. Percent recovery data for several sample types, as well as quality control procedures, are included. Samples were extracted via a liquid/liquid extraction centrifugation technique with dichloromethane. Cleanup was achieved by acid/base partitioning and automated gel permeation chromatography. Reverse phase high pressure liquid chromatography was used for separation of compounds employing an electrochemical detection system for quantitation. Sensitivities in the low picogram range were achieved for phenolic species in biosludge extract.

Two experiments are described, which involved the investigation of interactions between the nature of the conditioned stimulus (CS) and the nature of the unconditioned stimulus (UCS) in producing signal-centered behavior. In Experiment 1, rats received response-independent heat reinforcement in a cold environment. For some groups, this heat UCS was signaled by presentations of a standard aluminum retractable lever; for other groups, it was signaled by a retractable lever covered in acrylic fur (furry lever CS). Only the subjects that received the furry lever CS paired with heat exhibited differential CS-contact behavior, when compared with unpaired, aluminum lever, and warm control subjects. In Experiment 2, hungry rats received pairings of either an aluminum or a furry lever with food (UCS). When compared with unpaired controls, only the subjects that received the aluminum lever paired with food showed differential signal-directed behavior; the subjects receiving the furry lever CS did not show differential contact with the CS, but instead exhibited differential food tray entry behavior during CS presentation. In the two studies, the signal-directed behavior exhibited by subjects resembled either thermoregulatory or feeding behaviors characteristic of rats. The results suggest that signal-directed behavior is determined by a complex interaction between the ecological relevance of the CS and the nature of the UCS—an interaction that can best be described in terms of a behavior systems model of conditioned responding.

The choice of an internal fixation system for maxillofacial surgery is made difficult because of lack of information with respect to functional load. This study attempted to clarify some of the controversy with respect to maxillofacial use of these implants. Maximal compressive force to torque values were measured in standardized bone thicknesses of 1, 2, 3, and 4 mm. The screws tested were pretapped AO 1.5-, 2.0-, 2.7-, and 3.5-mm rescue screws and self-tapping Luhr, Champy, and AO 1.5- and 2.0-mm screws. Ten measurements were made for each screw type/bone thickness combination using a piezoelectric washer and torque screwdriver. It was apparent that for 1- and 2-mm bone thicknesses the use of self-tapping screws resulted in the highest compression values. In 3- and 4-mm bone thicknesses, pretapped screws offered the highest compression values. As expected, self-tapping screws had the highest torque values on insertion owing to torque loss in cutting the screw threads. The 2.7-mm screw offered no advantage over the 2.0-mm screws in 1- and 2-mm bone thicknesses but resulted in higher compression values in 3- and 4-mm bone thicknesses.