Football-related maxillofacial injuries.

Maxillofacial injuries sustained playing sports are becoming increasingly common, and in the UK where football is the most popular team sport, associated maxillofacial injuries are a regular occurrence. This study retrospectively examined data on patients who were referred with facial injuries sustained playing football between 2007 and 2019 (n = 265). Demographics, mechanism of injury, diagnosis, and treatment received were analysed. The mean (SD) age was 25 (11.0) years (range 3-85) and there was a strong male predominance (n = 256, 97% male). Facial fractures were diagnosed in 143 (54%) patients. The most common injury was a midface fracture and the most common mechanism of injury was a clash of heads. Patients with a facial fracture were significantly more likely to have sustained a concurrent head injury (p = 0.006). Those who were elbowed or punched were significantly more likely to have a facial fracture than a soft tissue or dentoalveolar injury (p ≤ 0.05). Players who clashed heads were significantly more likely to have a midface fracture (p ≤ 0.001). In conclusion, football-related maxillofacial injuries predominantly affect young adult males following a clash of heads. An elbow or punch to the face carries a significant risk of facial fracture and concurrent head injury. Therefore, to reduce the percentage of maxillofacial injuries seen in this sport, observed intentional contact between players, using an elbow or fist to the face in particular, must continue to carry the highest sanction.

Immediate compared with late repair of extracranial branches of the facial nerve: a comparative study.

The best outcomes after injury to the facial nerve are seen after immediate direct coaptation, but in practice, this happens infrequently. We ask whether late repair (between 3 weeks and 18 months) is comparable to immediate repair. In this prospective observational study over a two-year period (2016-18), we identified 18 patients (11 male and 7 female, mean (range) age 58 (23-94) years), who had sustained extracranial injuries to the facial nerve. Eight were identified in the acute phase (within 72hours of injury) and repaired (immediate repair group). Ten presented in the late phase beyond six months (late repair group), and had direct coaptation, neurolysis, nerve transfer, or non-vascularised or vascularised nerve grafts. Patients were followed up clinically with photographic or video analysis every three months using the Sunnybrook facial grading scale and Terzis scores as quantitative tools. In the immediate repair group six patients had direct nerve coaptations, one had a free vascularised nerve graft, and one a fascicular nerve flap. In the late repair group six patients had coaptations, two had nerve transfers, one had neurolysis, and one nerve transfer and a free vascularised nerve graft. The null hypothesis that there was no difference between immediate and late repair of the facial nerve in terms of clinical improvement was accepted. The overall facial grading scale between the two groups showed no significant difference (mean 97 compared with 87; 95% CI: -25.61 to 5.32; p=0.18). However, the individual volitional facial grading score for the affected division showed that immediate repair fared significantly better than late repair (mean 4.55 compared with 3.14; 95% CI: -2.5 to -0.3; p=0.027). Supermicrosurgical techniques, together with advanced systems for nerve identification allow for coaptation of the maximum number of injured nerve branches. These factors accounted for a 97% mean return of function after immediate repair and an 87% recovery in the late repair group. While quantitatively, immediate repair is best, the re-establishment of nerve-muscle continuity before degeneration of the motor endplate confers the best possible physiological outcome, and is far superior to any of the techniques used to treat chronic facial paralysis.

Verruciform Xanthoma of the Oral Mucosa: A Series of Eight Typical and Three Anomalous Cases.

In this series, there are 8 typical verruciform xanthomas of the oral mucosa and 3 anomalies, 1 polypoid, 1 florid, and 1 carcinomatous. All were characterized by infiltrates of CD68-positive xanthomatous histiocytes in the lamina propria. The 11 patients comprised 6 men and 5 women (mean age = 54.5 years, range = 40-69). Both keratinized and nonkeratinized sites were affected. A history of lichenoid inflammation was recorded in 5 patients. The polypoid xanthoma presented in a woman aged 54 years as a polyp of the labial commissure. The florid lesion affected the dorsum of the tongue of a man aged 54 years and at 20 mm was the largest of the 11 lesions, but the only one with candidal infection. The squamous cell carcinoma manifested as a papilloverrucous hyperkeratosis of the palatal gingiva in a man aged 69 years. The latter 2 (and 1 "typical" verruciform xanthoma) required re-excision, but none has since recurred.

Chondroid lipoma of the tongue: a report of two cases.

BACKGROUND: Chondroid lipoma affecting the oral cavity is rare and usually presents as a polyp of benign clinical appearance which is easily excised. However, the histopathological features of chondroid lipoma resemble liposarcoma due to the presence of lipoblasts and lack of mature cartilage. CASE REPORTS: The clinicopathological features of two cases of chondroid lipoma of the dorsum of the tongue, one in a 66-year-old woman and the other in a 43-year-old man, are described. CONCLUSION: Once the diagnosis had been established, no treatment other than surgical excision was necessary and in neither case has there been recurrence in two years of follow-up.

Efficient and accurate time-stepping schemes for integrate-and-fire neuronal networks.

To avoid the numerical errors associated with resetting the potential following a spike in simulations of integrate-and-fire neuronal networks, Hansel et al. and Shelley independently developed a modified time-stepping method. Their particular scheme consists of second-order Runge-Kutta time-stepping, a linear interpolant to find spike times, and a recalibration of postspike potential using the spike times. Here we show analytically that such a scheme is second order, discuss the conditions under which efficient, higher-order algorithms can be constructed to treat resets, and develop a modified fourth-order scheme. To support our analysis, we simulate a system of integrate-and-fire conductance-based point neurons with all-to-all coupling. For six-digit accuracy, our modified Runge-Kutta fourth-order scheme needs a time-step of Delta(t) = 0.5 x 10(-3) seconds, whereas to achieve comparable accuracy using a recalibrated second-order or a first-order algorithm requires time-steps of 10(-5) seconds or 10(-9) seconds, respectively. Furthermore, since the cortico-cortical conductances in standard integrate-and-fire neuronal networks do not depend on the value of the membrane potential, we can attain fourth-order accuracy with computational costs normally associated with second-order schemes.

Instability of elastic filaments in shear flow yields first-normal-stress differences.

Using slender-body hydrodynamics, we study the flow-induced deformation of a high-aspect-ratio elastic filament. For a filament of zero rest curvature rotating in a viscous linear shear flow, our model predicts a bifurcation to shape instabilities due to compression by the flow, in agreement with experimental observations. Further, nonlinear simulations of this shape instability show that in dilute solutions, flexibility of the fibers causes both increased shear thinning as well as significant nonzero first-normal-stress differences. These stress differences are positive for small-to-moderate deformations, but negative for large-amplitude flexing of the fibers.

Dynamic patterns and self-knotting of a driven hanging chain.

When shaken vertically, a hanging chain displays a startling variety of distinct behaviors. We find experimentally that instabilities occur in tonguelike bands of parameter space, to swinging or rotating pendular motion, or to chaotic states. Mathematically, the dynamics are described by a nonlinear wave equation. A linear stability analysis predicts instabilities within the well-known resonance tongues; their boundaries agree very well with experiment. Full simulations of the 3D dynamics reproduce and elucidate many aspects of the experiment. The chain is also observed to tie knots in itself, some quite complex. This is beyond the reach of the current analysis and simulations.

Computational modeling of orientation tuning dynamics in monkey primary visual cortex.

In the primate visual pathway, orientation tuning of neurons is first observed in the primary visual cortex. The LGN cells that comprise the thalamic input to V1 are not orientation tuned, but some V1 neurons are quite selective. Two main classes of theoretical models have been offered to explain orientation selectivity: feedforward models, in which inputs from spatially aligned LGN cells are summed together by one cortical neuron; and feedback models, in which an initial weak orientation bias due to convergent LGN input is sharpened and amplified by intracortical feedback. Recent data on the dynamics of orientation tuning, obtained by a cross-correlation technique, may help to distinguish between these classes of models. To test this possibility, we simulated the measurement of orientation tuning dynamics on various receptive field models, including a simple Hubel-Wiesel type feedforward model: a linear spatiotemporal filter followed by an integrate-and-fire spike generator. The computational study reveals that simple feedforward models may account for some aspects of the experimental data but fail to explain many salient features of orientation tuning dynamics in V1 cells. A simple feedback model of interacting cells is also considered. This model is successful in explaining the appearance of Mexican-hat orientation profiles, but other features of the data continue to be unexplained.