Untersuchungen zum Entstehungsmechanismus der isolierten Orbitabodenfraktur

Orbital Floor Fractures Comparing Different Kinds of Reconstruction: A Proposal for Restoration of Physiological Anatomy

ABSTRACT

The most effective treatment for orbital fractures is still under debate and different strategies are proposed in the literature. All such strategies focus on reconstruction of the orbital structure, neglecting the main function of the medial and inferior walls, these latter being constructed so as to break during high energy trauma. The aim of the authors is to highlight the difference between different reconstructive techniques in an orbital fracture restoration, being inclined to favor repair over reconstruction of the orbital floor, assuming that a second trauma could happen and reconstructive material left in the orbit may damage the visual apparatus in such a scenario. Following this theme, the authors propose a reconstruction strategy using a custom made stereolithographic model and resorbable plate made of polylactic acid mesh molded onto it. The mesh is used alone or in combination with bone graft, to obtain a better reparative result. At present, this approach is best suited to sports people and the young. Even if a deeper evaluation of the method would be useful, the series of case studies presented could be of stimulus for future discussion.

Repair of orbital floor fractures: our experience and new technical findings

We report our experience with the repair of the orbital floor fractures and present new technical findings. We evaluated 30 subjects with pure blowout fractures treated at the Department of Maxillofacial Surgery of the Federico II University of Naples, Italy, between 2005 and 2007. A preoperative examination by computed tomography scans provided classification of the orbital floor fractures into small and large fractures by measurement of the bone defect to choose the appropriate reconstructive implant materials, resorbable or nonresorbable. The clinical follow-up has been performed at 1 week, 1 month, 3 months, and 6 months. We observed a resolution of preoperative symptoms. The scar was not evident, and there was an absence of postoperative complications. We concluded that the use of resorbable materials for small orbital floor fractures and nonresorbable materials for large orbital floor fractures offers satisfactory results in both functional and aesthetic considerations. Furthermore, the new technical findings allow standardization of the surgical technique to be more accurate, also reducing the economic costs.

Forces charging the orbital floor after fractures

The objective of this study was first to establish a method to measure forces and displacement of the orbital content in defects of the orbital floor in truncated fresh and unfixed heads and second to characterize reconstruction materials with regard to punctuation strength and compression.Orbital floor defects (10 × 20 mm and 15 × 20 mm; 3 mm behind the orbital rim) were prepared after Le Fort I osteotomy. The values of force and displacement were recorded in 6 freshly frozen human heads. In addition, the punctuation strength of 2 reconstruction materials (polydioxanone [PDS] foil and collagen membrane) was evaluated using a Zwick Z010 TN1 universal testing machine. The forces of the orbital content (28.41 [SD, 1.6] g) applied to the defects of 10 × 20 mm and 15 × 20 mm with an intact periorbita were 0.04 (SD, 0.003) N (0.0002 MPa) and 0.07 (SD, 0.02) N (0.0002 MPa), respectively, and with a split periorbita were 0.06 (SD, 0.03) N (0.0003 MPa) and 0.08 (SD, 0.06) N (0.00026 MPa), respectively. The displacement values without reconstruction materials of the 10 × 20-mm and 15 × 20-mm defects were 0.94 (SD, 0.7) mm and 1.2 (SD, 0.5) mm, respectively. The PDS foil could withstand forces of 118.9 (SD, 14.1) N (0.375 MPa), and the collagen membrane could withstand forces of 44.5 (SD, 5.3) N (0.14 MPa). This is the first study to report forces charging the orbital floor. The presented results support the use of PDS foils and collagen membranes as reconstruction materials for orbital floor defects, at least in smaller and medium-sized fractures.

[Rare mechanisms of blowout fractures. Discussion of two case reports]

In the emergency room different forms of traumata with resulting insulating orbital blowout fracture are observed. The cause of accident is almost always impact to the central face with a solid object or on a hard surface. The hydraulic pressure theory and buckling force theory in terms of the pathomechanism are valid and accepted explanation models. We report two clinical cases of unusual injury mechanisms, which we discuss with reference to the available literature.