RESUMO
The specific traumatic mechanism that leads to the formation of the butterfly fragment is debated in literature. The aim of the present study is to analyze the biomechanics of fractures with a "butterfly" fragment, using a software that simulates the movement of the lines of force (and related iso-displacement points) that occur on the bone, when traumatic forces are applied on it. We have shown that the formation of the butterfly fragment derives from the application of three forces (compression, torsion and bending) with the bending force that acts by increasing the curvature of the long bone.
Assuntos
Borboletas , Fraturas Ósseas , Animais , Fenômenos Biomecânicos , Fixação Interna de Fraturas , SoftwareRESUMO
In a prospective study, 105 infants aged 3-12 months with acute otitis media were randomly assigned to one of three treatment groups: amoxycillin/clavulanate ('Augmentin') alone (36 patients), myringotomy plus placebo (35 patients), or augmentin plus myringotomy (34 patients). The last two groups were double-blinded. Bacterial pathogens, mainly Haemophilus influenzae (of which 20% were beta-lactamase producers) and Streptococcus pneumoniae, were isolated from 60% of the ear exudates and all isolates were sensitive to augmentin. Most of the infants improved clinically within 3-6 days irrespective of the treatment protocol. As judged by otoscopy, 60% of the patients receiving augmentin, with or without myringotomy, recovered completely compared with 23% of patients treated with myringotomy plus placebo. Treatment with augmentin was also more effective than myringotomy with regard to persistence of ear infection. In the myringotomy plus augmentin group closure of the incision and resolution of the discharge from the incision site was faster than in the myringotomy plus placebo group. The addition of myringotomy to augmentin did not seem to affect either the persistence of the infection after treatment or the residual middle ear effusion.