A Priori Subcell Limiting Approach for the FR/CPR Method on Unstructured Meshes

A priori subcell limiting approach is developed for high-order flux reconstruction/correction procedure via reconstruction (FR/CPR) methods on two-dimensional unstructured quadrilateral meshes. Firstly, a modified indicator based on modal energy coefficients is proposed to detect troubled cells, where discontinuities exist. Then, troubled cells are decomposed into nonuniform subcells and each subcell has one solution point. A second-order finite difference shock-capturing scheme based on nonuniform nonlinear weighted (NNW) interpolation is constructed to perform the calculation on troubled cells while smooth cells are calculated by the CPR method. Numerical investigations show that the proposed subcell limiting strategy on unstructured quadrilateral meshes is robust in shock-capturing.     

A High Order Bound Preserving Finite Difference Linear Scheme for Incompressible Flows

We propose a high order finite difference linear scheme combined with a high order bound preserving maximum-principle-preserving (MPP) flux limiter to solve the incompressible flow system. For such problem with highly oscillatory structure but not strong shocks, our approach seems to be less dissipative and much less costly than a WENO type scheme, and has high resolution due to a Hermite reconstruction. Spurious numerical oscillations can be controlled by the weak MPP flux limiter. Numerical tests are performed for the Vlasov-Poisson system, the 2D guiding-center model and the incompressible Euler system. The comparison between the linear and WENO type schemes, with and without the MPP flux limiter, will demonstrate the good performance of our proposed approach.     

Clinical application of automated virtual orbital reconstruction for orbital fracture management with patient-specific implants: A prospective comparative study

The aim of the study was to compare automated and manually conducted (slice-by-slice) virtual orbital wall reconstruction in terms of PSI design, manufacture, and clinical application for orbital fracture management.Patients with orbital wall fractures were evaluated for the potential for treatment with PSI, based on automated virtual wall reconstruction; these formed the main group. The surgical outcomes of these main-group patients' treatments were compared with those of the control group, which comprised patients randomly selected for this study, each of whom had the same orbital trauma patterns and were also managed with PSI. However, the control group patients were treated using ‘slice-by-slice’ virtual orbital reconstruction.Mean volume differences between the intact and reconstructed orbit were 0.65 ± 0.26 cm³ in the main group (n = 23) and 0.57 ± 0.23 cm³ in the control (n = 27; p = 0.837). In both groups, no cases of implant malposition or enophthalmos were detected after surgery. Orbital shape difference was similar for the main group and the control, at ?3.3 ± 3.5% and 3.25 ± 2.5%, respectively (p = 0.929). Diplopia was diagnosed at the 3-month follow-up in 13.0% of the main group and in 11.1% of the control (p = 0.651). The average times spent on computer-aided design (CAD) procedures, including segmentation, virtual orbital reconstruction, and PSI design, were 36.7 ± 6.9 min in the main group and 72.9 ± 7.7 min in the control group (p < 0.001).Within the limitations of the study it seems that PSI based on automated virtual reconstruction is a relevant alternative treatment option for orbital fractures because of its clinical efficacy that is similar to PSI based on a ‘slice-by-slice’ CAD protocol.     

Functional outcomes of soft palate free flap reconstruction following oropharyngeal cancer surgery

IntroductionThe objective of this study was to assess the impact of surgical resection and free flap reconstruction of soft palate cancer on speech, swallowing and quality of life, and to identify the factors influencing functional outcomes and quality of life.Material and methodsPatients treated with surgical resection of squamous cell carcinoma and free-flap reconstruction of the soft palate were reviewed at least 12 months after surgery. Speech was assessed using the Hirose intelligibility scoring system, nasalance scoring, GRBAS scoring and the Voice Handicap Index 30 (VHI30) questionnaire. Swallowing was assessed by fiberoptic endoscopy and the Deglutition Handicap Index (DHI). Quality of life was assessed using EORTC QLQ-C30 and QLQ-H&N35 questionnaires.Results29 patients were included. Speech outcomes were satisfactory, demonstrating normal or slightly below normal speech intelligibility in 75.9% of the patients, moderate or no rhinolalia in 72.4% of the patients and mean overall VHI30 scores indicative of slight or no handicap in 86.2% of the patients. Swallowing outcomes were satisfactory, with mean overall DHI scores indicative of slight or no handicap in 82.8% of the patients. Patient quality of life was preserved as demonstrated by mean quality of life and functioning scales scores all superior to 80%.ConclusionThe sequelae arising from surgical resection and free-flap reconstruction of soft palate cancer are tolerable, involving slight handicap in terms of speech and swallowing and relatively little impact on quality of life.     

Patients’ narratives of orthognathic treatment for facial asymmetry: a qualitative study

To explore patients’ experiences of orthognathic treatment for facial asymmetry and their adaptation to facial changes after surgery, we did a qualitative, cross-sectional study of patients after treatment for non-cleft asymmetry at two UK sites. A total of 15 patients aged 19-40 years were approached after being identified using patient databases and clinical notes. Individual and photo-elicitation interviews were conducted covering experiences prior to treatment, during treatment, and after surgery. Interviews were transcribed and thematic narrative analysis undertaken. Participants were largely positive about their orthognathic treatment. The following themes were identified: preoperative (becoming aware, negative impacts of asymmetry, committing to treatment, establishing expectations), pre-surgery orthodontics and inpatient experiences (challenges and coping strategies, preparedness, support, and shared experiences); and postoperative (surgery as ‘worth it’, positive impacts of treatment, adapting to facial change). Undergoing orthognathic surgery was portrayed as a journey involving recognisable narratives (treatment unfinished, threat of liminality, treatment as resolution, and treatment as transformation). Patients’ experiences of facial asymmetry are associated with feeling ‘abnormal’, and negative impacts, and orthognathic treatment for facial asymmetry is worthwhile. Having the feeling that something is ‘wrong’ legitimised by clinicians allows patients access to a recognisable treatment narrative (resolution). Orthognathic treatment is also described as transformation from ‘normal abnormality’ to being ‘normal’. Nevertheless, the associated challenges can be frustrating, particularly if resolution is hard to envisage. Further psychological input could help patients cope with these challenges and the complex process of adapting to facial change.     

Oropharyngeal shedding of herpesviruses before and after BNT162b2 mRNA vaccination against COVID-19

IntroductionConcerns were raised over an increase in Bell's palsy, herpes simplex and herpes zoster after BNT162b2 vaccination, all are manifestations of herpesviruses reactivation. As herpesviruses commonly reactivate in the oropharynx, we have hypothesized that oropharyngeal shedding of herpesviruses will increase after vaccination.MethodsImmune-competent Adults, excluding those using topical steroids or manifesting symptomatic herpesvirus infection, were sampled before BNT162b2 vaccination and one week after. Herpesviruses 1–7 shedding was tested with a multiplexed PCR.ResultsIn 103 paired samples the prevalence of herpesviruses was similar before and after vaccination: HSV1, 3.9% vs. 5.8% (p = 0.75); HSV2, 0% vs. 1% (p = not applicable, NA); VZV, 0% vs. 0% (p = NA); EBV, 14.6% vs. 17.5% (p = 0.63); CMV, 0% vs. 0% (p = NA); HHV6, 4.9% vs. 7.8% (p = 0.55); HHV7, 71.8% vs. 72.8% (p = 1); any herpesvirus, 73.8% vs. 74.8% (p = 1).DiscussionWe did not find evidence for increased oropharyngeal reactivation of herpesviruses one week after BNT162b2.