How Accurate Are Surgeons at Calculating Orbital Volumes?

PURPOSE: Bilateral orbital volume (OV) symmetry is imperative for successful orbital reconstruction to prevent complications such as enophthalmos, diplopia, and orbital dystopia. The purpose of this study was to determine the accuracy of surgeon-led in-house OV calculation for reconstructed orbits after orbital floor fracture. MATERIALS AND METHODS: This is a retrospective cross-sectional observational study of maxillofacial computed tomography scans for patients undergone orbital fracture repair by Emory Oral and Maxillofacial service at Grady Memorial Hospital (Atlanta, Georgia) from 2018 to 2020.The primary predictor variable was OV calculation approach (outsourced vs surgeon-led in-house approach). The primary outcome variable was OV. Secondary variables were age, gender, and race. Interobserver reliability was calculated with a 2-way mixed-effects model, intraclass correlation coefficients, 95% confidence intervals, and P values. Differences between OV (in-house and outsourced) were calculated using student t-test. Statistical significance was determined at P < .05. RESULTS: During the study period, 172 patients sustained orbital floor fracture. Of them, 49 patients (31 male, 18 females; 98 orbits) with the mean age of 41.3 years (range, 19 to 89 years) met inclusion criteria. Subjects with incomplete medical records and inadequate computed tomography scans were excluded from the study. The racial distribution in descending order was 87.8% African American, 8.2% Caucasian, 2% Hispanic, and 2% Asian. There was excellent inter-rater reliability for calculating uninjured OV (OV-U, P < .0001) and reconstructed OV (OV-R, P < .0001). The mean OV difference of outsourced approach was 0.8 cm3and for surgeon-led in-house approach was 0.07 cm3. There was no significant difference in OV difference between outsourced and in-house approach (P = .16). CONCLUSIONS: In conclusion, using open-source 3-dimensional imaging software is a reliable and a predictable method at calculating reconstructed OV in patients who underwent open reduction and internal fixation of orbital fractures. By having this software in our personal computers and laptops, one can easily calculate OVs in an efficient manner.

Do Racial Differences in Orbital Volume Influence the Reconstruction of Orbital Trauma.

PURPOSE: Successful orbital reconstruction relies on an accurate restoration of orbital volume (OV). The purpose of this study was to determine if the OV of African American (AA) subjects differs from that of Caucasian subjects. METHODS: The authors implemented a retrospective observational study of successive subjects who received a maxillofacial computed tomography (CT) scan at a level I trauma center between 2017 and 2020. The primary predictor variable was race (AA/Caucasian). The primary outcome variable was orbital volume. Two independent examiners calculated OV with an open access OsiriX MD software version 10.0.5 (Pixmeo, Switzerland). Inter-rater reliability was calculated. Differences between races, genders, and sides were tested using independent samples t test with a significance of P < .05. RESULTS: Sixty subjects (120 orbits) were included in the study. The mean age was 36.7 (SD ± 13.2) years with a range of 22 to 78 years. Gender distribution was equal with 30 male (50%) and 30 female (50%) subjects. Inter-examiner reliability was 0.973. The mean OV of AA and Caucasians was 22.38 and 23.23 cm3, respectively (P = .07). The mean OV of AA and Caucasian males was 23.92, and 24.17cm3, respectively (P = .71). The mean OV in AA and Caucasian females was 20.84 and 22.28cm3, respectively (P = .013). CONCLUSIONS: African-American female subjects appear to have a smaller OV when compared with Caucasians which may influence orbital reconstruction. Laterality does not appear to be associated with any differences in OV.

Patterns of Pediatric Facial Fractures.

OBJECTIVE: The aim of this study was to assess patterns of maxillofacial trauma in the pediatric population in Atlanta. This information is important to help guide management and allocate resources for treatment of maxillofacial injuries at Children's Healthcare of Atlanta (CHOA). METHODS: This study was a retrospective chart review of children who presented from 2006 to 2015. Inclusion criteria were: (1) age 18 years old or younger, (2) presentation to emergency department, (3) diagnosis of maxillofacial fractures, and (4) evaluation by Oral and Maxillofacial Surgery, Otolaryngology, or Plastic Surgery services. Medical records were reviewed to record demographic, mechanism of injury, fracture location, and yearly incidence of injury. Descriptive statistics were computed to summarize findings and overall trends. RESULTS: During the study period, 39,833 patients were identified. Of them, 1995 met the inclusion criteria. The majority were male (n = 1359, 68%) with an average age of 9.4 years old (range of 1 month to 18 years old). Mechanisms of injury were motor vehicle collisions (MVC) (n = 597, 29.9%), fall (n = 565, 28.3%), sports injury (n = 317, 15.9%), pedestrian struck (n = 215, 10.8%), assault/abuse (n = 204, 10.2%), other (n = 81, 4.1%), or gunshot wound (n = 16, 0.8%). Fracture sites were mandible (n = 519, 26%), complex (n = 479, 24%), nasal (n = 419, 21%), dentoalveolar (n = 279, 14%), orbital (n = 259, 13%), and maxilla (n = 40, 2%). Males had a higher incidence of assault than females (n = 185, 91% of assaults). The incidence of maxillofacial trauma increased with age with a peak incidence in 13 to 16-year-olds (n = 566, 28.3%). During the years examined, there was an upward trend in MVCs as the etiology with a peak incidence of facial fractures due to MVCs occurring in 2015. All other mechanisms remained constant during this time period. CONCLUSIONS: There was an increase in pediatric facial fractures secondary to motor vehicle collisions from 2007 to 2015 despite improvements in regulations, traffic safety, and technology.

Aberrant Activation of Notch1 Signaling in Glomerular Endothelium Induces Albuminuria.

RATIONALE: Glomerular capillaries are lined with a highly specialized fenestrated endothelium and contribute to the glomerular filtration barrier. The Notch signaling pathway is involved in regulation of glomerular filtration barrier, but its role in glomerular endothelium has not been investigated due to the embryonic lethality of animal models with genetic modification of Notch pathway components in the endothelium. OBJECTIVE: To determine the effects of aberrant activation of the Notch signaling in glomerular endothelium and the underlying molecular mechanisms. METHODS AND RESULTS: We established the ZEG-NICD1 (notch1 intracellular domain)/Tie2-tTA/Tet-O-Cre transgenic mouse model to constitutively activate Notch1 signaling in endothelial cells of adult mice. The triple transgenic mice developed severe albuminuria with significantly decreased VE-cadherin (vascular endothelial cadherin) expression in the glomerular endothelium. In vitro studies showed that either NICD1 (Notch1 intracellular domain) lentiviral infection or treatment with Notch ligand DLL4 (delta-like ligand 4) markedly reduced VE-cadherin expression and increased monolayer permeability of human renal glomerular endothelial cells. In addition, Notch1 activation or gene knockdown of VE-cadherin reduced the glomerular endothelial glycocalyx. Further investigation demonstrated that activated Notch1 suppression of VE-cadherin was through the transcription factors SNAI1 (snail family transcriptional repressor 1) and ERG (Ets related gene), which bind to the -373 E-box and the -134/-118 ETS (E26 transformation-specific) element of the VE-cadherin promoter, respectively. CONCLUSIONS: Our results reveal novel regulatory mechanisms whereby endothelial Notch1 signaling dictates the level of VE-cadherin through the transcription factors SNAI1 and ERG, leading to dysfunction of glomerular filtration barrier and induction of albuminuria. Graphic Abstract: A graphic abstract is available for this article.

Endotracheal Tube Fixation via a Modified Ivy Loop in a Pediatric Patient With Facial Burns: A Technical Note.

Securing an endotracheal tube in a child with a facial burn is crucial but often challenging. The traditional method of using a facial apparatus or tape tied around the lower face is not suitable in the setting of open facial wounds as it limits wound care and, if necessary, skin grafting. We describe a straightforward, quick method to secure the endotracheal tube by means of a modified ivy loop in a pediatric patient.

Hypotensive anesthesia: Comparing the effects of different drug combinations on mean arterial pressure, estimated blood loss, and surgery time in orthognathic surgery.

UNLABELLED: Sevoflurane, an inhalational hypotensive anesthetic agent with a vasodilatory property, has been commonly used as a single agent to induce hypotension and effectively decrease blood loss in orthognathic surgery. However, it is common for patients to receive other hypotensive anesthetic agents in combination with sevoflurane. The purpose of our retrospective cohort study is to investigate whether administering an additional hypotensive agent has greater effect at reducing mean arterial pressure (MAP), estimated blood loss (EBL) and surgery time during orthognathic surgery. MATERIAL AND METHODS: 57 subjects, aged 0-89 of both genders, who underwent orthognathic surgery were investigated in this study. Each patient's anesthesia records were reviewed to record the following variables of interest: EBL, duration of surgery, and MAP reduction in %. 41 subjects were placed in Group I and they received sevoflurane alone. 16 subjects were placed in Group II and they received sevoflurane plus a "supportive" agent. These "supportive" agents were esmolol, labetalol, metoprolol, nicardipine, and dexmedetomidine. The significant differences between two groups were assessed by using ANCOVA and p < 0.05 was regarded as significant. Wilcoxon signed-rank test was used to look for differences in surgery time. RESULTS: Subjects in Group II experienced a greater reduction in MAP during surgery than subjects in Group I, 27.30% and 20.44%, respectively (p = 0.027). There was no significant difference for sex (p = 0.417) or age group (p = 0.113) in estimated blood loss, however. The mean surgery time in Group I was 1.93, 2.77, and 4.54 h with respect to LeFort, BSSO/IVRO, and double jaw surgery. Patients in Group II had a mean surgery time of 1.73, 2.07, and 5.64 h with respect to LeFort, BSSO/IVRO, and double jaw surgery. No statistically significant difference was demonstrated in surgery time between Group I vs. Group II (p > 0.05). Subjects in Group II experienced, on average, more blood loss than subjects in Group I, 355.50 ml and 238.90 ml, respectively. CONCLUSION: The use of multi-drug combination may offer significant advantage of reducing patients' mean arterial pressure. However, this has no significant effect on reducing blood loss or surgery time in comparison to sevoflurane alone.

Constitutively active Notch1 signaling promotes endothelial­mesenchymal transition in a conditional transgenic mouse model.

Endothelial-mesenchymal transition (EndoMT) is a process in which endothelial cells lose their cell-type­specific characteristics and gain a mesenchymal cell phenotype. The Notch signaling pathway is crucial in the regulation of EndoMT; however, its roles have not been fully studied in vivo. In a previous study, we reported the generation of transgenic mice with a floxed ß-geo/stop signal between a CMV promoter and the constitutively active intracellular domain of Notch1 (IC-Notch1) linked with a human placental alkaline phosphatase (hPLAP) reporter (ZAP-IC-Notch1). In this study, we examined the results of activating IC-Notch1 in endothelial cells. ZAP-IC­Notch1 mice were crossed with Tie2-Cre mice to activate IC-Notch1 expression specifically in endothelial cells. The ZAP-IC-Notch1/Tie2-Cre double transgenic embryos died at E9.5-10.5 with disruption of vasculature and enlargement of myocardium. VE-cadherin expression was decreased and EphrinB2 expression was increased in the heart of these embryos. Mesenchymal cell marker α-smooth muscle actin (SMA) was expressed in IC-Notch1­expressing endothelial cells. In addition, upregulation of Snail, the key effector in mediating EndoMT, was identified in the cardiac cushion of the double transgenic murine embryo heart. The results of the present study demonstrate that constitutively active Notch signaling promotes EndoMT and differentially regulates endothelial/mesenchymal cell markers during cardiac development.

Constitutive notch signaling in adult transgenic mice inhibits bFGF-induced angiogenesis and blocks ovarian follicle development.

Notch signaling is important in angiogenesis during embryonic development. However, the embryonic lethal phenotypes of knock-out and transgenic mice have precluded studies of the role of Notch post-natally. To develop a mouse model that would bypass the embryonic lethal phenotype and investigate the possible role of Notch signaling in adult vessel growth, we developed transgenic mice with Cre-conditional expression of the constitutively active intracellular domain of Notch1 (IC-Notch1). Double transgenic IC-Notch1/Tie2-Cre embryos with endothelial specific IC-Notch1 expression died at embryonic day 9.5. They displayed collapsed and leaky blood vessels and defects in angiogenesis development. A tetracycline-inducible system was used to express Cre recombinase postnatally in endothelial cells. In adult mice, IC-Notch1 expression inhibited bFGF-induced neovascularization and female mice lacked mature ovarian follicles, which may reflect the block in bFGF-induced angiogenesis required for follicle growth. Our results demonstrate that Notch signaling is important for both embryonic and adult angiogenesis and indicate that the Notch signaling pathway may be a useful target for angiogenic therapies.