Tracheal intubation in coronavirus disease 2019 (COVID-19) patients creates a risk to physiologically compromised patients and to attending healthcare providers. Clinical information on airway management and expert recommendations in these patients are urgently needed. By analysing a two-centre retrospective observational case series from Wuhan,

This study investigated the maximum number of collaterals that can be maintained by 1 axon during regeneration of rat peripheral nerve. The tibial nerve was transected, the proximal residual, with its variable number of axons, was fixed to the distal stump and served as the donor nerve. The number of myelinated axons was calculated after 12 weeks. An increasing ratio of distal stump axon numbers to proximal donor nerve axon numbers of 1.0, 1.83, 3.64 and 7.97 yielded ratios of regenerative myelinated axon numbers to proximal donor axon numbers of 0.98, 1.51, 2.39, 2.89, respectively, with an estimated maximum value of approximately 3.3 using the Hill function. The tibial function indexes and nerve conduction velocities of the regenerated tibial nerve were –44.1 ± 5.1 and 43.2 ± 5.3 m/s, –57.5 ± 4.7 and 18.6 ± 4.3 m/s, –80.2 ± 7.1 and 12.7 ± 3.7 m/s, and –85.4 ± 5.7 and 10.5 ± 3.9 m/s, respectively. It has been suggested that 1 axon can regenerate and maintain up to 3 or 4 collaterals in regenerated rat peripheral nerve.

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Background and purpose Metaphyseal fractures heal in a rapid fashion that is different from the bone shaft healing process. Animal studies have focused on diaphyseal fractures. We investigated the metaphyseal fracture-healing process in rabbits.Animals and methods 60 rabbits (divided into 12 groups) underwent proximal tibial osteotomy, anatomical reduction, and fixation with screws. After surgery, the proximal tibiae were harvested at different time points for histology.Results No obvious osteonecrosis or bone resorption were found 2 weeks after surgery. From day 5 to week 5, woven bone or new trabeculae formed. From week 2, remodeling into lamellar bone started and reached a peak at week 6. These 3 stages overlapped. Histomorphometry showed that the structure changed as a unimodal curve.Interpretation The healing process of metaphyseal fractures appears to differ from the commonly studied healing process in diaphyseal fractures. It is rapid, and can be divided into 4 histological stages: cellular activation and differentiation, formation of woven bone, transformation of woven bone into lamellar bone, and further remodeling.

Virtual reality simulation is more efficient than mannequin in simulation-based training of flexible fiberoptic manipulation in novices, but similar effects can be achieved in both modalities after adequate training.

Functional recovery is usually poor following peripheral nerve injury when reinnervation is delayed. Early innervation by sensory nerve has been indicated to prevent atrophy of the denervated muscle. It is hypothesized that early protection with sensory axons is adequate to improve functional recovery of skeletal muscle following prolonged denervation of mixed nerve injury. In this study, four groups of rats received surgical denervation of the tibial nerve. The proximal and distal stumps of the tibial nerve were ligated in all animals except for those in the immediate repair group. The experimental groups underwent denervation with nerve protection of peroneal nerve (mixed protection) or sural nerve (sensory protection). The experimental and unprotected groups had a stage II surgery in which the trimmed proximal and distal tibial nerve stumps were sutured together. After 3 months of recovery, electrophysiological, histological and morphometric parameters were assessed. It was detected that the significant muscle atrophy and a good preserved structure of the muscle were observed in the unprotected and protective experimental groups, respectively. Significantly fewer numbers of regenerated myelinated axons were observed in the sensory-protected group. Enhanced recovery in the mixed protection group was indicated by the results of the muscle contraction force tests, regenerated myelinated fiber, and the results of the histological analysis. Our results suggest that early axons protection by mixed nerve may complement sensory axons which are required for promoting functional recovery of the denervated muscle natively innervated by mixed nerve.

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Retrobulbar block is safe and effective as an alternative to systemic fentanyl and could provide better pain management, hemodynamic suppression, and stress response suppression in pediatric vitreoretinal surgery.