Three-dimensional finite element analysis of a newly developed aliform internal fixation system for occipitocervical fusion.

For patients with occipital malformation, it is difficult to obtain reliable stability using three screws on the midline. A new aliform occipitocervical internal fixation system was designed. The occiput was fixed with 3, 7, or 11 screws, and a three-dimensional finite element model of the system was established.

[A study of the prevalence of obstructive sleep apnea hypopnea syndrome in drivers].

Objective: To study the prevalence of snoring and obstructive sleep apnea hypopnea syndrome (OSAHS) in drivers in Chengde city.

Methods: The prevalence of snoring and OSAHS in drivers was investigated by a questionnaire, and some of the drivers with more severe snoring were also evaluated by polysomnographic study.

Results: Among the 718 investigated drivers, never snoring was reported in 68.