This insertion point and direction were chosen to ensure that reduction rotation force was maximally powerful and effective in the direction opposite the rotation vector of the zygomatic fracture. In medial-dominant or bidirectional rotation fractures, it was horizontally inserted from the medial area of the zygomatic body to the zygomatic arch. In inferior-dominant rotation fractures, the wire was inserted vertically from the inferior area of the zygomatic body to the lateral orbital rim. The scale was excellent for no asymmetry, good for minimal asymmetry or depression, poor for moderate asymmetry or depression.Ī thick K-wire (1.5 mm in diameter) was inserted into the thick zygomatic body near the fracture line, furthest from the hinge of the rotation fracture, to about 4 cm deep, with a drilling device applied in the same operative field of the intraoral approach ( Fig. The patients also were asked the degree of malar symmetry using the same scale by seeing their zygoma through a mirror at the last follow-up. An independent physician evaluated the degree of zygomatic bone symmetry based on the 3D CT images. Preoperative, immediately postoperative, and 6-month follow-up facial 3D CT images were collected for evaluation of case outcomes. However, severe depressed quadripod fracture in inferior-dominant rotation type with severe fracture displacement of zygomatic arch or zygomaticofrontal suture were excluded from this study. All fractures had mild fracture displacement or green stick fracture of the zygomatic arch or zygomaticofrontal suture with or without mild comminution. These zygomatic fractures were classified as follows according to the dominant rotational direction of the zygomatic body on preoperative facial three-dimensional computed tomography (3D CT) images to determine the direction of K-wire insertion in advance: 17 fractures with inferior-dominant rotation, nine fractures with medial-dominant rotation, and 13 fractures with inferior and medial bidirectional rotation. Among them, intraoral K-wire reduction was performed in 39 inferomedially impacted fractures, in which the zygomatic body was incompletely reduced by a simple reduction technique with a bone elevator through an intraoral approach. Inferomedially rotated zygomatic fractures were in 63 of the 82 patients with zygomatic fracture who underwent surgery from January 2015 to December 2019. However, the strong hook insertion or traction procedure often causes additional bone fracture or displacement or fragmentation of the comminuted zygomaticomaxillary fracture and can cause difficult bone fixation as well as additional sinus injury and its related complications. Therefore, the theoretical required reduction force is equal to the actual force for complete reduction motion of the zygoma, resulting in a more accurate and effective reduction with a lower force than seen in bone elevator reduction. In zygomatic reduction with a bone hook, the hooking point is located on the medial or inferior fracture margin of the zygomatic body farthest from a hinge or at the zygomatic recess of the maxillary sinus. Therefore, if the inferomedial portion of the fractured zygoma body is severely stuck in the maxillary sinus, it is often difficult to achieve complete anatomical reduction by only conventional bone-elevator reduction, especially in medial rotation fractures, resulting in need for an additional powerful and effective reduction force. The traction force at this point must be stronger than the force required to reduce the impacted zygomaticomaxillary fracture furthest from the hinges. The application point of the bone elevator is commonly the posterior surface of the zygomatic body in the most anterior portion of the zygomatic arch, which is close to the hinges. In conventional techniques adopting the intraoral approach with upper gingivobuccal sulcus incision, a bone elevator or bone hook is inserted underneath the zygomatic body, and anterolateral traction force is applied.
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