[Blow out fracture of the medial orbital wall--plastic repair with tantalum mesh].

Two cases of blow out fracture of the medial orbital wall were reported. The one was a 14 year-old boy and the other was a 32 year-old man. After hitting the eye against another man or a hard object, the patients felt diplopia, especially on lateral gaze toward the injured side. The blow out fracture was able to be diagnosed by plain roentgenography or tomography. The fractured bone as well as the entrapped soft tissue were clearly detected by CT scan. The fractures occurred at the thinnest part of the Lamina orbitalis ossis ethmoidalis (Lamina papyracea) in both cases. Objects with diameter larger than that of the bony orbit pressed the eye ball and other soft tissue into the orbital cavity, and the blow out fracture occurred in the medial orbital wall in each case. The skin was incised along the supero-medial margin of the orbit and subperiostial dissection was done. The entrapped medial rectus muscle was observed in one case and unverified in the other. Entrapment of the orbital soft tissue other than medial rectus muscle may also have caused diplopia. Tantalum mesh, used for repair is quite thin material. It has much plasticity and little possibility of damaging the orbital tissue and of causing postoperative bleeding. No complication occurred after operation and diplopia disappeared completely or nearly completely in the cases reported.