2020–2021 BCSC Basic and Clinical Science Course™
7 Oculofacial Plastic and Orbital Surgery
Part I: Orbit
Chapter 6: Orbital Trauma
Zygomaticomaxillary complex (ZMC) fractures (Fig 6-3) are also referred to as quadripod fractures because the zygoma is usually fractured at 4 of its articulations with the adjacent bones: (1) frontozygomatic suture, (2) inferior orbital rim, (3) zygomatic arch, and (4) lateral wall of the maxillary sinus. ZMC fractures involve the orbital floor to varying degrees. If the zygoma is not significantly displaced, treatment may not be necessary. ZMC fractures can cause globe displacement, lateral canthal dystopia, cosmetic deformity, diplopia, and trismus (limitation of mandibular opening) due to fracture impingement on the coronoid process of the mandible.
Figure 6-3 Zygomaticomaxillary complex (ZMC) fracture. A, ZMC, anterior view. Downward displacement of the globe and lateral canthus result from frontozygomatic separation and downward displacement of the zygoma and the floor of the orbit. B, Globe ptosis and lateral canthal dystopia result from depressed ZMC fracture. C, Axial computed tomography (CT) scan shows depression of malar prominence and telescoping of bone fragment into the maxillary sinus. D, Intraoperative view shows rigid plate fixation of supralateral orbital rim fracture that was performed in addition to fixation of the inferior rim and lateral maxillary buttress.
(Part A modified with permission from Converse JM, ed. Reconstructive Plastic Surgery: Principles and Procedures in Correction, Reconstruction, and Transplantation. 2nd ed. Philadelphia: Saunders; 1977:2. Parts B–D courtesy of M. Reza Vagefi, MD.)
When treatment is indicated, the best results are obtained with open reduction of the fracture and rigid plate fixation (see Fig 6-3D). Exact realignment and stabilization of the lateral maxillary buttress and the lateral orbital wall are essential for accurate fracture reduction and can be achieved through a combination of eyelid and buccal sulcus incisions. If the lateral maxillary buttress is only mildly displaced, complete reduction and fixation can be accomplished through an eyelid incision.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.