Severe posttraumatic facial deformities resulting from extensive facial fractures have long been challenging problems for the plastic surgeon. Delay in operative management secondary to combined life-threatening injuries, failure to appreciate the magnitude of the initial facial injury, inadequate operative treatment, and operative complications contribute to their occurrence [1].

With more widespread adoption of craniofacial techniques, traditional approaches, such as repeated onlay bone grafts and alloplastic implants, have been relegated to secondary roles. Minor contour irregularities can be smoothed by grinding or onlay bone graft, but large onlay grafts are not recommended, especially in the malar area [2,3]. Restoration of normal anatomic position of displaced facial bones by appropriate osteotomies has become the standard of treatment for severe posttraumatic facial deformities.

In treatment of craniofacial and midfacial fractures, various approaches and designs of surgical incision have been described. Among them, bicoronal approach has been indicated for severe comminuted zygomatic arch and zygomatic bone fractures because it allows excellent access to the temporal and infratemporal spaces for management of severe traumatic injuries. Moreover, this is the approach of choice for delayed correction of major zygomatic deformities by osteotomy or extensive bone grafting [4]. However, there are many potential complications following a bicoronal incision, such as infection, hematoma, alopecia, visible scarring, and facial nerve injury [5]. Some surgeons advocate the lateral eyebrow approach for initial access to the zygomaticofrontal region [6], but it offers only a narrow operative field and may result in eyebrow scarring and hair loss [7]. Therefore, we have adopted a zygomaticofrontal suture osteotomy technique using transconjunctival incision with lateral paracanthal extension. We performed a retrospective review of clinical cases underwent correction of malunioned zygoma with the approach to evaluate outcomes following this method.

Between June 2009 and September 2015, corrective osteotomies were performed in 14 patients with malunioned zygoma (Table 1). All operations were performed by a single surgeon. The mean age of patients was 48 years (range, 28–69 years). Eight patients were males, and six were females. Injury mechanisms included motor vehicle collision (n=4), fall (n=6), and assault (n=4). The causes of the malunions are as follows: delayed operation due to life-threatening injuries such as intracranial hemorrhage (n=8), missed diagnosis of fractures with non-intervention (n=2), and incomplete reduction/reconstruction at initial surgical intervention (n=4). The mean interval from injury to operation was 16 months (range, 12 months to 4 years), and the mean follow-up was 1 year (range, 4 months to 3 years) (Table 1).

For preoperative assessment, all patients underwent clinical evaluations for bone integrity, position of the globe, change in canthal attachment, and soft tissue status. Radiographic evaluation (plain films, computed tomography [CT] scans) and ophthalmologic consultation were also performed [8].

Medical records were reviewed for detailed operation notes, follow-up records, and perioperative photographs. Facial bone plain films and CT scans were analyzed for posttraumatic facial deformities. Among these, zygomatic arch views were used to measure degrees of correction (Fig. 1). In zygomatic arch view, the most anterior point of zygoma-orbit complex was used as a standard. A horizontal line was drawn from uppermost (anterior) point of normal side zygoma (Line A), and another line is drawn from that of malunioned zygoma (Line B). We measured the distance between the two lines before and after surgery for evaluating the degree of correction. In addition, to assess the horizontal width change, vertical line drawn from nasal septal bone was used as the base line. The line from the base line to the most lateral point of normal side zygoma denotes line C, and the line from the base line to the most lateral point that of malunioned zygoma denotes line D. We also measured the distance difference between the two lines before and after surgery for evaluating horizontal width change.

All patients received transconjunctival incisions with lateral paracanthal extension and gingivobuccal incision. Via the surgical incisions, we could easily access the infraorbital rim, orbital floor, zygomaticofrontal suture, and anterior surface of the maxilla. There was no need for coronal or supra-brow incisions. For 6 patients with symptoms of infraorbital numbness, nerve decompression was carried out by widening the infraorbital canal. Zygomaticomaxillary osteotomy was extended to the infraorbital foramen from the infraorbital rim and oral maxilla. The infraorbital canal was carefully explored, and bone spicules and canal edges were removed. Bone grafts to the malar area were performed in only one patient (No. 5), who had a history of communited zygomatic bone fracture (Table 1). Once skeletal foundations were reset, some ancillary procedures such as dermofat grafts and fat injection were performed in 6 patients as secondary operations. Among the six patients who received secondary operations, three patients underwent dermofat graft on nose to correct deformed nasal contour, and one patient received fat graft for correction of soft tissue atrophy on cheek and malar area. The average preoperative height difference in zygomatic arch view was 3.5 mm (range, 1.5 to 6.0 mm), and the height difference had decreased to 0.6 mm (range, 0 to 2.0 mm) after surgery. The average preoperative width difference in zygomatic arch view was 4.9 mm (range, 3.0 to 7.5 mm), and the width difference was decreased to 0.4 mm (range, 0 to 2.0 mm) after surgery, a reduction close to normal measurement value (Table 2). One patient (No. 3) experienced oral wound dehiscence with sinus abscess that was treated by wound irrigation and sinus mucosa stripping. Among the 6 patients who received nerve decompression, gradual improvement was observed in 4 patients, with two remaining patients continuing to experience numbness after 1 year (Table 2). The lateral paracanthal incision scars were inconspicuous, and none of the patients complained about the relatively well-hidden incision scar.

Complete regional exposure is usually required to achieve correction of malunioned zygoma. Traditionally, a bicoronal flap combined with a lower eyelid incision and an upper buccal sulcus incision has been used for exposure of the zygomaticofrontal suture area because this approach gives excellent exposure of the upper craniofacial skeleton [9]. Using the bicoronal approach, the calvarium, forehead, supraorbital rim, orbital roof and lateral orbital rim can be widely exposed. Reflection of the temporalis muscle enables access to the lateral wall of the orbit and temporal fossa. Converse et al. [10] noted that osteotomy for reduction of old fractures is an indication for the coronal approach in craniomaxillofacial trauma patients. Although a bicoronal approach can widely expose the lateral side of the zygoma-orbit complex, there are many potential complications. Coronal incisions can result in alopecia, and therefore, this incision should be carefully modified or not be used in patients with male pattern baldness. Other possible complications of the bicoronal approach include sensory disturbances of the supraorbital and preauricular areas, motor deficits of the frontal branches of the facial nerve, and hematomas under the flap [11].

Pozatek et al. [6] stated that "the lateral eyebrow approach is also applicable to treatment of old or malunioned zygoma fracture." This approach gives direct access to the zygomaticofrontal suture line. However, it may leave an objectionable scar and partial brow depilation. Moreover, the overextended incision can make damage to motor nerve branches to the orbicularis oculi [4].

Chuong and Kaban [7] advocated the use of upper eyelid incisions for initial access to zygomatic complex fractures. This approach offers greater versatility and enhanced accessibility to the superolateral rim compared to the lateral eyebrow approach. The soft tissues of the upper lid are thin and resilient, so the incision site can be easily maneuvered onto the bony surfaces. However, Langsdon et al. [12] reported that this approach was associated with a higher incidence of postoperative complications, such as eyelid-related complications and infection. Yanagisawa [13] suggested that this approach is not suitable for lateral or inferior displacements.

Subciliary incisions are also acceptable because it is desirable for exploration, sectioning of the orbital floor, accurate repositioning of the segment, and placement and stabilization of graft or implants. However, this approach can lead to visible scars and persistent edema, so careful attention to surgical detail can produce an aesthetic infraorbital scar line and little change for infraorbital nerve damage [4].

To the best of our knowledge, this article is the first examination of transconjunctival incision with paracanthal extension for corrective osteotomy of malunioned zygoma. With this approach, we were able to expose the zygomaticofrontal suture and sphenozygomatic suture sufficiently to perform osteotomy. Compared with previous methods, this procedure has many advantages [14,15]. First, our technique entails fewer skin incisions and minimal dissection, and can therefore reduce operation time, complication rate, and recovery time. Second, it produces inconspicuous scars and provides direct access to the zygomaticofrontal region for fracture reduction and plate fixation.

The lateral paracanthal incision technique, in which the lid is transected approximately 2 to 3 mm from the lateral canthus, does not disrupt the canthal angle and its attachment to the orbit, with less morbidity and better cosmetic outcomes than traditional lateral canthotomy. It also facilitates anatomical repair of the lid because of easy identification of the gray line, which serves as an important landmark [8]. In our series, there was no lid malpositioning, the most concerned complication of the lateral canthotomy.

As previously mentioned, the key to successful treatment of posttraumatic facial deformities is the establishment of a correct diagnosis and formulation of a well-organized treatment plan. The vertical, horizontal, and sagittal dimensions of the craniofacial skeleton should be reestablished first. Even if skeletal reconstruction itself is symmetric, there can be soft tissue problems that produce asymmetric and deformed facial contour.

Cohen et al. [1] noted that the general goals of posttraumatic facial deformity reconstructions are (1) to restore normal and anatomic bone alignment, (2) to reestablish the underlying skeletal support prior to addressing soft-tissue abnormalities, and (3) to replace missing tissue with like tissue. Perino et al. [4] stated that aesthetic derangements in the periorbital soft tissues occur secondary to bony displacement. Tessier [16] reported that several procedures, such as rhinoplasty, lateral canthopexy, and scar excision may be needed following reconstruction as secondary operations. In some of our cases, soft tissue augmentation procedures such as dermofat grafts or fat injections were needed after skeletal correction.

Prior to each operation, we practice mock practice operations using skull models (Fig. 3). Three-dimensional printing techniques combined with computed tomographic imaging were used to generate a precise skull model. With the aid of the three-dimensional model and mock surgery, we were able to determine the exact osteotomy point and proper positioning of the zygomatic bone complex in our patients.

There are some limitations of this study. First, this study was retrospective. To address this limitation, all clinical information was verified in electronic medical records to ensure accuracy of clinical information. The small number of patients included is also a limitation. There is a possibility that unrecognized complications might be elucidated if sufficient numbers of patients were enrolled in the study. Finally, this study was case series study and did not compare across various reconstructive methods. Thus, there is a need for new prospective comparative studies evaluating the outcomes of correcting malunioned zygoma with various approaches. Despite these limitations, we believe that transconjunctival incision with lateral paracanthal extension combined with upper buccal incision is a valid alternative to the bicoronal approach for osteotomy of malunioned zygoma.