title: Posttraumatic orbital emphysema: a numerical model.
abstract: Orbital emphysema is a common symptom accompanying orbital fracture. The pathomechanism is still not recognized and the usually assumed cause, elevated pressure in the upper airways connected with sneezing or coughing, does not always contribute to the occurrence of this type of fracture. Observations based on the finite model (simulating blowout type fracture) of the deformations of the inferior orbital wall after a strike in its lower rim. Authors created a computer numeric model of the orbit with specified features-thickness and resilience modulus. During simulation an evenly spread 14400 N force was applied to the nodular points in the inferior rim (the maximal value not causing cracking of the outer rim, but only ruptures in the inferior wall). The observation was made from 1 · 10(-3) to 1 · 10(-2) second after a strike. Right after a strike dislocations of the inferior orbital wall toward the maxillary sinus were observed. Afterwards a retrograde wave of the dislocation of the inferior wall toward the orbit was noticed. Overall dislocation amplitude reached about 6 mm. Based on a numeric model of the orbit submitted to a strike in the inferior wall an existence of a retrograde shock wave causing orbital emphysema has been found.
authors.affiliation: Otolaryngology Department, Medical University of Gdansk, Smoluchowskiego Street 17, 80-214 Gdańsk, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Skorek
authors.affiliation: Faculty of Civil and Environmental Engineering, Gdansk University of Technology, Poland.
authors.forename: Paweł
authors.initials: P
authors.lastname: Kłosowski
authors.affiliation: Otolaryngology Department, Medical University of Gdansk, Smoluchowskiego Street 17, 80-214 Gdańsk, Poland.
authors.forename: Lukasz
authors.initials: L
authors.lastname: Plichta
authors.affiliation: Ophthalmology Department, Medical University of Gdansk, Poland.
authors.forename: Dorota
authors.identifier: 0000-0003-4992-854X
authors.initials: D
authors.lastname: Raczyńska
authors.affiliation: Faculty of Civil and Environmental Engineering, Gdansk University of Technology, Poland.
authors.forename: Marcin
authors.initials: M
authors.lastname: Zmuda Trzebiatowski
authors.affiliation: Otolaryngology Department, Medical University of Gdansk, Smoluchowskiego Street 17, 80-214 Gdańsk, Poland.
authors.forename: Paweł
authors.initials: P
authors.lastname: Lemski