Application of IMF screws to assist internal rigid fixation of jaw fractures: our experiences of 168 cases.

Intermaxillary fixation (IMF) screws were first introduced to achieve IMF as a kind of bone borne appliance for jaw fractures in 1989. Because this method can overcome many disadvantages associated with tooth borne appliance, IMF screws have been popularly used for jaw fractures since then. From March 2011 to February 2014, we treated 168 cases with single or multiple jaw fractures by open reduction and a total of 705 IMF screws were intraoperatively applied in all the cases to achieve IMF and maintain dental occlusion as an adjuvant to open reduction. The numbers, implantation sites and complications of IMF screws were retrospectively analyzed. In our experience, we found that IMF screws were important to assist open reduction of jaw fractures but their roles should be objectively assessed and the reliability of open reduction and internal rigid fixation must be emphasized. Much attention should be paid when implanting.

A new model of blast injury from a spherical explosive and its special wound in the maxillofacial region.

OBJECTIVE: The goal of this study was to establish an efficient explosive model with spherical explosives for the study of blast injury and its wound characteristics in the maxillofacial region. METHODS: Different spherical explosives were used to produce blast waves and to establish the wound model. Fresh sheep heads as the targets were used for the study of wound characteristics. The wounding parameters and the injuries of targets after explosion were observed. RESULTS: The overpressure values of blast waves decreased exponentially along with the increase of distances to explosives and so did the tissue damage. The blast injury is quite different from other injuries and is more serious. A kind of special "split fracture" of the mandibles was found. CONCLUSIONS: The new explosive wound model with spherical explosives can be used for the study of blast injury in the laboratory. The injury manner of blast wave and the local anatomy of tissues resulted in the special wound characteristics.