Please review our Terms and Conditions of Use and check box below to share full-text version of article. Introduction  A catastrophic earthquake with a moment magnitude of 7. Figure 1 Open in figure viewer PowerPoint. Tectonic setting of the Longmen Shan fault zone. Light green colored areas in the relief indicate lacks of DEM data.
The epicenter is marked with a star, and the aftershocks that occurred from 12—19 May are shown as black dots [ National Earthquake Information Center , ]. Solid lines are fault traces drawn after Densmore et al. Analyzed regions are indicated by blue frames in the inset. Ground Displacements for the Sichuan Earthquake  Figure 2 shows the estimated range offset field over the entire analyzed area. Figure 2 Open in figure viewer PowerPoint. Displacement field in range component. Warm and cold colors represent displacements away from and toward the satellite, respectively.
A sharp color discontinuity, across which the ground motion is in the opposite direction, is highlighted with a solid line, and is recognized to be just along the Beichuan fault trace indicated by a dotted line. Figure 3 Open in figure viewer PowerPoint. Displacement field for the paths a and b in left range and right azimuth components, respectively. In the range offset field, warm and cold colors stand for displacements away from and toward the satellite, respectively, and in the azimuth toward and opposite the satellite flight direction, respectively. Displacement boundaries are highlighted with solid lines.
Arrows in the inset of the range and azimuth fields features a deforming area located at the southeastern foot of the Pengguan massif. Figure 4 Open in figure viewer PowerPoint. Schematic fault motions inferred from the offset fields. Uncertainties and Reliabilities of Measured Offsets  To confirm how much errors are included in the measured offset fields, we calculate offsets using two preseismic images for the paths and , which have almost the same perpendicular baseline B perp as the coseismic image pairs shown in Figure 3 Table S1. Supporting Information Auxiliary material for this article contains seven figures and two tables.
Additional file information is provided in the readme. Filename Description grlsupreadme. A filtering procedure for azimuth streaks. Horizontal displacement vectors for the area corresponding to the path Observed and synthetic range offset fields. Details of F1, F2, and F3. Avouac, J. Ayoub , S. Leprince , O.
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A fibrous capsule was surrounding the mass presumed to be hematoma. The fibrous capsule was dissected and partially removed because of the adhesions to the surrounding orbital structure and implant. A dark brown hematoma was identified and evacuated from the subperiosteal plane above the previously inserted Medpor implant, which was removed during this operation Fig.
The patient did not wish to remove the implant in the contralateral orbit.
Orbital Floor Fractures
Postoperatively, the ptoptosis was fully resolved. At one week, the remaining symptoms improved significantly by one week without diplopia or visual disturbance. No complications, such as pain, ocular muscle restriction, recurrence of hematoma, or bleeding were noted during the month follow-up period. Various implants have been used to reconstruct the orbital floor and prevent soft tissue herniation. In particular, Medpor is a non-absorbable implant material with high flexibility, and has a multiporous structure and the ability to form vasculature toward adjacent tissues.
Medpor provides structural support, is well tolerated by surrounding tissue, and has a low risk of exposure and infection [ 2 ]. Various complications associated with alloplastic implants have been reported but are rare and found in isolated case series. A thick or malpositioned implant can induce superior or anterior displacement of the eyeball.
If dead space is present between the implant and the orbital floor, fluid can easily collect, and the implant becomes very susceptible to infection. Due to its proximity to the maxillary sinus, the orbital floor fracture is exposed to risk of infection. Implants with smooth surfaces, such as silicone or Teflon, form a capsule around the defect in many cases, and vessels cannot easily penetrate the implant. This allows bacteria to colonize more easily around the implant.
However, venous perforating branches from the orbital floor penetrate into the multiporous structure of Medpor. Thus, Medpor has a relatively low risk of bacterial infection but has a risk of bleeding or hematoma formation [ 3 , 4 ].
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Many studies have analyzed the relationship between alloplastic implants and complications after orbital wall surgery. Common complications are proptosis, hyperglobus, inferior scleral show, orbital discomfort, diplopia, and motility restrictions. A few cases had clinical evidence of optic nerve compression. In a review of orbital floor reconstructions with Medpor, Lee et al. An implant can cause low-grade irritation with evidence of chronic inflammation and form a fibrous capsule around the irritation.
Gilhotra et al. This hypothesis was further supported by Mauriello et al.
Dufresne et al. In our case, the hemorrhage presented as a large cystic subperiosteal mass over the orbital floor implant.
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We presumed the mass to represent infected implant or hemorrhagic cyst; however, no evidence of abscess or a foreign body reaction was detected. We speculate that the etiology was rupture of capillaries growing within the implant pseudocapsule. Several authors have reported cases of late complications after alloplastic implant surgery and onset varied from weeks to years.
Such hemorrhages have occurred with various implants and do not appear to be common with one particular implant type [ 1 ]. Sometimes the severity of an ocular injury such as an open globe with acute vision loss can be very distracting to the physicians evaluating the patient. It's crucial to not miss other potentially life-threatening injuries. Viozzi, who sees all types of facial trauma, offers a few tips for treating ocular or orbital injuries:. Ocular injuries, in particular, may be quite severe and cause stress for providers involved, as well as for the patient and family.
Most patients with any form of facial fracture — such as orbital — will experience moderate to severe pain, which needs to be managed. This is due to a relatively high density of sensory pain fibers in the facial and orbital regions, thus making pain symptoms significant. Orbital fractures can be obvious, but frequently are subtle and can therefore present a diagnostic challenge. If any suspicion for fracture is present, it's appropriate to order a CT scan to determine if orbital trauma exists.
However, if a patient exceeds the capacity of the low-volume trauma center, imaging should be deferred, especially if life threats are present. If the patient is unconscious, diagnosis is even more problematic absent patient interaction, and orbital injuries can be overlooked. Missing an orbital or ocular injury at the outset is also possible in polytrauma cases, where the primary focus is the trauma ABCs — concerns that might rapidly take the patient's life. When a patient arrives with an obvious eye injury, a robust general trauma assessment is the first step in caring for the patient.
Once more-serious injuries have been ruled out or addressed, one may consider evaluation and treatment of the ocular trauma. Evaluation of visual acuity, detection of soft tissue injuries, observation of epiphora, evaluation of extraocular muscle function and globe position, and palpation for bony deformities should proceed in a systematic manner. With corneal abrasion, which is very common in orbital trauma, patients can be profoundly uncomfortable, making pain control particularly important.