Three-dimensional Measurement of the Zygomatic-maxillary Complex in the Class III Malocclusion Patients with Maxillary Retrusion.

This study investigated the anatomic features of the zygomatic-maxillary complex in patients with maxillary retrusion without clefts. Individuals were grouped, and craniofacial measurements were performed for 21 individuals with skeletal Class III malocclusion with maxillary retrusion (CIII) and 48 individuals from the control group (CG). We evaluated the predetermined hard-tissue and soft-tissue points of the facial profile in each group. Independent sample t -tests were performed to determine the differences between groups (significance set at P <0.05). Multiple points on the midface, including the most posterior point on the contour of the maxillary alveolar process, lowest point of the zygomaticomaxillary suture, furthest point to the zygomatic self-base plane, superior point in the infraorbital foramen, and lowest point of the inferior margin of the orbit to the coronal plane were smaller in CIII than in CG (all P <0.05). The soft tissue thickness in these regions was significantly increased compared with that in the normal group. In summary, for class III malocclusion patients with maxillary retrusion, the deficiency in the midface gradually decreased going upward, with the deficiency at the maxillary alveolar level being the most serious. To some extent, soft tissues compensate for the deficiencies in the facial skeleton, and standard Le Fort I osteotomy advancement was sufficient to achieve a harmonious appearance.

Application of Computer-Assisted Preoperative Planning in Treating Congenital Bilateral Zygomatico-Maxillo-Mandibular Fusion: A Case Report and Literature Review.

Congenital fusion of the jaws (syngnathia) is a rare facial malformation with an unknown etiology. This disease may vary in severity with adhesion of soft tissue and bony fusion. It can be anterior fusion, unilateral or bilateral fusion, and complete fusion. The main problem of these patients is the difficulty of airway maintenance and feeding, and the most common postoperative complication is the relapse of bony fusion. Here, we report a young male patient with bony syngnathia, involving bilateral fusion of the ascending ramus and body of the mandible with the maxillary complex. We performed bone isolation by computer-assisted preoperative planning and used an insertional temporalis flap to fix the wound surface to prevent refusion of bone.

Reduction Malarplasty Using Customized Surgical Stent Based on 3D Virtual Surgery, CAD/CAM, and 3D Printing Technology: Case Series.

ABSTRACT: The zygomatic bone is a structure that protrudes symmetrically on both sides of the midface and plays an important role in the overall aesthetic appearance of the face. Unlike Caucasians, the mesocephalic facial shape is predominant in Asians, and therefore, many people have a relatively laterally developed zygomatic bone. In Asians, when the zygomatic bone is excessively developed, it gives a strong and stubborn image, and aesthetically, many people want to reduce the zygomatic bone because they prefer an oval and slim face.To reduce the excessive zygomatic bone, a reduction malar- plasty through an intraoral and preauricular approach has been performed. Although reducing the zygomatic bone is not a big problem in most cases of symmetric reduction malarplasty, it is not easy to produce surgical results as intended by the surgeon in asymmetric malar patients or patients requiring a three-dimensional (3D) change of zygoma. In addition, because of the mobility of the zygoma segment, it may be difficult to drill holes and fix plate after osteotomy. Moreover, these factors can increase the possibility of malunion or nonunion.In this study, cutting guides made with the aid of 3D virtual surgery, 3D printing, and customized titanium plates manufactured with the computer-aided design/computer-aided manufacturing technology are used for 8 patients to maximize the recovery of 3D symmetry and minimize complications through accurate fixation after surgery. During the surgical procedures, screw hole drilling and osteotomy were performed using a cutting guide, and then, the malar segment was fixed by matching the premade customized plates with the predrilled holes. As a result of checking the accuracy of the surgery by superimposing the postoperative 3D cone beam computed tomography image and virtual surgery data based on the skull base, the 2 images almost overlapped and no significant differences were observed, so it was confirmed that the operation was performed exactly as planned.When using the 3D technology, it is possible to perform a more accurate surgery in patients with asymmetry due to congenital anomalies or trauma as well as simple asymmetry, so it can be concluded that using the 3D technology can overcome the limitations and disadvantages of the conventional method as in the cases in this study. The accurate prediction of soft tissue is still insufficient, and further research is needed to overcome this limitation.

Is Augmentation Required to Correct Malar Deficiency With Maxillary Advancement?

PURPOSE: Patients with maxillary hypoplasia also have malar deficiency; therefore, planning can include consideration for simultaneous malar augmentation. The purpose of this study was to compare pre- and postoperative profiles of patients who underwent Le Fort I advancement, with and without malar augmentation, to assess the subjective perception of changes in malar eminence projection. MATERIALS AND METHODS: Patients who had maxillary advancement and mandibular setback with and without malar augmentation were evaluated through a survey consisting of pre- and postoperative photographs that were assessed by professionals and laypersons, and a visual analog scale was used to assess the malar region. Next, pre- and postoperative images were shown side by side and participants were asked to indicate which patients had undergone malar augmentation. Statistical analysis used Wilcoxon signed rank test, independent-samples t test, Spearman rank order correlation, and Mann-Whitney U tests. RESULTS: Of 43 patients, 23 met the inclusion criteria and only 7 of the 23 patients received simultaneous malarplasty. Patients in the 2 groups were perceived as having an increase in malar eminence projection postoperatively. In the malarplasty and non-malar cohorts, laypersons and professionals noted an increase in projection (P < .05). Laypersons tended to overestimate the number of malar procedures performed (sensitivity, 59.5%; specificity, 56.8%), whereas professionals were better able to accurately exclude malar augmentation (sensitivity, 44.2%; specificity, 69.9%). CONCLUSIONS: Most patients with maxillary hypoplasia undergoing Le Fort I advancement can expect a subjective improvement in malar projection. The decision for malar augmentation at the time of maxillary advancement should be considered based on patient desires, but, in general, maxillary advancement alone might be sufficient for an optimal malar esthetic outcome.

Zygomatic bone shape in intentional cranial deformations: a model for the study of the interactions between skull growth and facial morphology.

Intentional cranial deformations (ICD) were obtained by exerting external mechanical constraints on the skull vault during the first years of life to permanently modify head shape. The repercussions of ICD on the face are not well described in the midfacial region. Here we assessed the shape of the zygomatic bone in different types of ICDs. We considered 14 non-deformed skulls, 19 skulls with antero-posterior deformation, nine skulls with circumferential deformation and seven skulls with Toulouse deformation. The shape of the zygomatic bone was assessed using a statistical shape model after mesh registration. Euclidian distances between mean models and Mahalanobis distances after canonical variate analysis were computed. Classification accuracy was computed using a cross-validation approach. Different ICDs cause specific zygomatic shape modifications corresponding to different degrees of retrusion but the shape of the zygomatic bone alone is not a sufficient parameter for classifying populations into ICD groups defined by deformation types. We illustrate the fact that external mechanical constraints on the skull vault influence midfacial growth. ICDs are a model for the study of the influence of epigenetic factors on craniofacial growth and can help to understand the facial effects of congenital skull malformations such as single or multi-suture synostoses, or of external orthopedic devices such as helmets used to correct deformational plagiocephaly.

A Rare Patient with Facial Duplication.

Facial duplication, in whole or in part, is a very rare malformation. It may be symmetrical or asymmetric. Those cases that have been reported in the literature constitute a spectrum extending from simple nasal duplication to complete separation of 2 faces. Up to now there are some reports of eye, nose, mandible, or maxilla duplication separately. But there is no report of oral orifice or lips duplication. The present article reports a case of a newborn girl who presented with 2 mouths and also duplication of zygoma and maxilla. Then, we describe her stages of treatment from birth through now that she has 20 years.

Bilateral Malar Reconstruction Using Patient-Specific Polyether Ether Ketone Implants in Treacher-Collins Syndrome Patients With Absent Zygomas.

The authors performed bilateral malar reconstruction using polyether ether ketone implants in 3 patients with Treacher-Collins syndrome with absent, as opposed to hypoplastic, zygomata. These patient-specific implants were fabricated using computed-aided design software reformatted from three-dimensional bony preoperative computed tomography images. The first time the authors performed this procedure the implant compressed the globe resulting in temporary anisocoria that was quickly recognized intraoperatively. The implant was immediately removed and the patient made a full-recovery with no ocular disturbance. The computer-aided design and manufacturing process was adjusted to include periorbital soft-tissue boundaries to aid in contouring the new implants. The same patient, and 2 further patients, subsequently underwent malar reconstruction using this soft tissue periorbital boundary fabrication process with an additional 2 mm relief removed from the implant's orbital surface. These subsequent procedures were performed without complication and with pleasing aesthetic results. The authors describe their experience and the salutary lessons learnt.

Reduction Malarplasty that Uses Malar Setback Without Resection of Malar Body Strip.

BACKGROUND: Various surgical methods have been developed and used to reduce prominent malar bones. The most common reduction malarplasty methods are resection of the bone strip of the malar bone with L-osteotomy or I-osteotomy, followed by setback and fixation. However, these methods could be associated with complications due to the bone strip resection. The present article introduces an effective and safe method that reduces the zygoma without resection of a malar bone strip. METHODS: Through preauricular and intraoral incisions, we performed the current L-osteotomy without resection of the malar bone strip using a reciprocating saw. We created back space for zygoma setback by removing the posterior wall of the maxillary sinus, which acted as a bony interference. We were able to set the lateral segment of the zygoma back about 3-5 mm. We fixed the zygomatic arch with wire and the zygomatic body with a prebent plate and screw. Thereafter, we performed rasping of the anterior part of the zygoma to achieve sufficient reduction. After performing our reduction malarplasty for 139 patients, clinical outcomes were evaluated. RESULTS: Most patients responded to the satisfaction survey as excellent and good. There were no major complications 6 months postoperatively. CONCLUSIONS: The key of our method of reduction malarplasty is to create posterior space without resecting the malar body strip, which results in an effective setback. This method enables surgeons to effectively maintain the zygoma body, which leads to high satisfaction rates and fewer complications. Therefore, this study proved the safety and effectiveness of our method of reduction malarplasty. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Correction of Unilateral Congenital Zygomatico-Mandibular Fusion.

Sygnathia, or fusion of the jaw, is a rare condition in children, occurring either in isolation or as part of a larger overall syndrome. Consequences of this bony fusion may range from feeding difficulties to a complete inability to protect the airway. Owing to the uncommon nature of this problem and the high recurrence of bony fusion, standardized treatment protocols do not yet exist, making individual reports particularly useful for guiding the first-time management of such patients. In this report, we describe the case of a male infant with complete bony fusion of the right zygomatic maxillary complex to the mandible. Fusion was separated by osteotomy, repair of soft tissue with acellular dermal matrix/grafting, and plate separation. Serial jaw manipulation and operative stretching was necessary to prevent refusion of syngnathia even in the long term.

Congenital Bilateral Zygomatico-Maxillo-Mandibular Fusion Associated With Gum Fusion.

A congenial syngnathia is very rare condition. It can be simple mucosal fusion (synechiae), or complete bony fusion (synostosis) between the maxilla or zygoma and the mandible. Fusion of the ascending ramus of mandible to maxilla and zygoma is less common than fusions of the alveolar ridges of the mandible to the maxilla. Bony syngnathia is either isolated or complex in form. There are 59 cases of congenital bony syngnathia reported in the literature: the first report was by Burket in 1936. There are 16 reported cases of zygomatico-maxillo-mandibular fusion. In the reported cases, women expressed the isolated form more commonly whereas men demonstrated a more complex pattern of disease. The authors present another patient of bony syngnathia involving bilateral fusion of the ascending ramus and body of the mandible with the maxillary complex in a young man. Early surgery was performed to release the bony and soft tissue fusion on the eighth day from the baby's birth. A second operation was performed for recurrence when the baby was 2.5 months old. A customized splint, an intense postoperative program of mouth exercises, and close follow-up aims to prevent further refusion.

Unilateral zygomatic hypoplasia correction by L-shaped zygomatic osteotomy with natural coral.

PURPOSE: Zygomatic osteotomy is a common method of zygomatic hypoplasia correction. Natural coral is considered to be a good bone substitute. Few studies on unilateral zygomatic hypoplasia correction by zygomatic osteotomy with natural coral have been reported. This study was performed to evaluate the clinical morphological results and surgical outcomes of unilateral zygomatic hypoplasia correction by L-shaped zygomatic osteotomy with natural coral. METHODS: From 1996 to 2012, a total of 42 patients with hypoplastic zygomas treated by L-shaped zygomatic osteotomy with natural coral were included in this study. Based on facial analysis results and x-ray and CT measurements, the degradation of natural coral, new bone formation, and clinical outcomes were observed and recorded. RESULTS: All surgical procedures achieved satisfactory results without complications. During the stabilization period of about 12 to 15 months, all natural coral blocks were completely degraded and replaced by new bone. Good mechanical strength and continuity of the new bone and good zygomatic asymmetry were achieved in each patient. No recurrence was observed during the follow-up period. CONCLUSION: L-shaped zygomatic osteotomy with natural coral is an effective method of unilateral zygomatic hypoplasia correction.

Virtual Resection and Subsequent Design of a Patient-Specific Alloplastic Implant in the Preoperative Planning and Surgical Treatment of a Venous Malformation of the Zygoma.

The authors present here the case of a 63-year-old female who developed a venous malformation of the left zygoma. These lesions are typically managed with nonoperative treatment, until or unless overt complicating symptoms require more aggressive surgical intervention. Reconstruction of the zygoma represents a challenge for the operating surgeon, considering its complex three-dimensional anatomy. Traditionally, the surgeon would estimate the appropriate margins of resection intraoperatively, and then design a construct to fit the defect using autologous bone grafts, allografts, or one of the various available alloplastic materials; however, for this patient preoperative virtual surgical planning was used. Using reconstructed three-dimensional images from the patient's maxillofacial computed tomography scan, the margins of the excision were virtually defined and the lesion "excised" during a preoperative planning session based on the specifications of the reconstructive surgeon. This process then allowed the design and production of custom osteotomy guides, and a patient-specific polyetheretherketone (PEEK) implant to match the resulting defect. The authors believe this methodology allows for a more efficient and precise overall procedural experience and reconstructive result, and has innumerable potential applications in the surgical treatment of craniofacial abnormality.

Congenital maxillomandibular syngnathia: a new management technique using distraction techniques.

Complex zygomaticomandibular syngnathia is an extremely rare condition with an unknown etiology. The main goal of the surgery is to release the ankylosis, establish good functioning mandible, and prevent reankylosis, if possible. In our case, we offer a new solution to have an adequate oral opening and to prevent reankylosis. After the release of bony syngnathia, we placed a distractor between mandibular segment and maxillozygomatic complex. To our best knowledge, this is the only syngnathia case in the literature treated using distraction techniques. There is a major improvement in the patient's status. Distraction may broaden our horizons in this rare and difficult-to-treat deformity.

Patient-specific polyetheretherketone facial implants in a computer-aided planning workflow.

PURPOSE: In the present study, we report an innovative workflow using polyetheretherketone (PEEK) patient-specific implants for esthetic corrections in the facial region through onlay grafting. The planning includes implant design according to virtual osteotomy and generation of a subtraction volume. The implant design was refined by stepwise changing the implant geometry according to soft tissue simulations. MATERIALS AND METHODS: One patient was scanned using computed tomography. PEEK implants were interactively designed and manufactured using rapid prototyping techniques. Positioning intraoperatively was assisted by computer-aided navigation. Two months after surgery, a 3-dimensional surface model of the patient's face was generated using photogrammetry. Finally, the Hausdorff distance calculation was used to quantify the overall error, encompassing the failures in soft tissue simulation and implantation. RESULTS: The implant positioning process during surgery was satisfactory. The simulated soft tissue surface and the photogrammetry scan of the patient showed a high correspondence, especially where the skin covered the implants. The mean total error (Hausdorff distance) was 0.81 ± 1.00 mm (median 0.48, interquartile range 1.11). The spatial deviation remained less than 0.7 mm for the vast majority of points. CONCLUSIONS: The proposed workflow provides a complete computer-aided design, computer-aided manufacturing, and computer-aided surgery chain for implant design, allowing for soft tissue simulation, fabrication of patient-specific implants, and image-guided surgery to position the implants. Much of the surgical complexity resulting from osteotomies of the zygoma, chin, or mandibular angle might be transferred into the planning phase of patient-specific implants.

Malformations of the zygomatic and maxillary regions.

The maxillofacial region develops during 3 to 8 weeks in an embryo. The process involves neural crest cell migration and proliferation as well as facial protrusion jointing and fusion. The maxillofacial region is one of the predilection sites of congenital malformations. We treated a 5-year-old Chinese boy with abnormal development of the left maxillofacial region. We describe in detail the patient's characteristics, diagnosis, and treatment processes and try to explain the possible causes of the disease.

Zygomaticocoronoid ankylosis: a rare clinical condition leading to limitation of mouth opening.

Ankylosis, between the coronoid process and the zygoma, is a rare occurrence. A review of the literature has disclosed 15 reported cases of this disorder. True incidence of this condition might be even higher. Zygomaticocoronoid ankylosis might have been encountered by many surgeons, and yet it has been misdiagnosed or overlooked.In this article, the treatment of a 14-year-old patient with zygomaticocoronoid ankylosis is presented. With regard to treatment, there are various opinions as to whether the coronoidectomy be performed intraorally or extraorally. In this study, treatment of the patient has been performed via intraoral approach.

Congenital zygomatico-mandibular fusion (pseudo-syngnathia?) in conjunction with unilateral anophthalmia: review of terminology and classification.

Syngnathia per se is a rare congenital disorder. A literature survey reveals a total of 26 cases of syngnathia in the English literature since 1936, of which only seven cases involved fusion of the ascending ramus of the mandible to the posterior portion of the maxilla and zygomatic complex. The remaining 19 involved fusion of the alveolar ridges of the maxilla and mandible. This is a unique case of fusion of the mandible to the zygomatic complex presenting with a unilateral anophthalmic orbit in an 18-day-old neonate. The use of the term syngnathia has been reviewed and a modification in classification has been suggested.

Successful surgical treatment of mandibulo-zygomatic arch synostosis secondary to trauma in a dog.

This is a report of mandibulo-zygomatic arch synostosis in a dog 7 mo after trauma to the maxilla. Advanced diagnostic imaging was considered essential for characterization of the condition and treatment planning. Surgical excision of the bony proliferation and physiotherapy resulted in improved function within 6 wk.

Quantitative Morphologic Analysis of Cranial Vault in Twist1+/- Mice: Implications in Craniosynostosis.

BACKGROUND: The haploinsufficiency in the TWIST1 gene encoding a basic helix-loop-helix transcription factor is a cause of one of the craniosynostosis syndromes, Saethre-Chotzen syndrome. Patients with craniosynostosis usually require operative release of affected sutures, which makes it difficult to observe the long-term consequence of suture fusion on craniofacial growth. METHODS: In this study, we performed quantitative analysis of morphologic changes of the skull in Twist1 heterozygously-deleted mice (Twist1+/-) with micro-computed tomographic images. RESULTS: In Twist1+/- mice, fusion of the coronal suture began before postnatal day 14 and progressed until postnatal day 56, during which morphologic changes occurred. The growth of the skull was not achieved by a constant increase in the measured distances in wild type mice; some distances in the top-basal axis were decreased during the observation period. In the Twist1+/- mouse, growth in the top-basal axis was accelerated and that of the frontal cranium was reduced. In the unicoronal suture fusion mouse, the length of the zygomatic arch of affected side was shorter in the Twist1+/- mouse. In one postnatal day 56 Twist1+/- mouse with bilateral coronal suture fusion, asymmetric zygomatic arch length was identified. CONCLUSION: The authors'results suggest that measuring the length of the left and right zygomatic arches may be useful for early diagnosis of coronal suture fusion and for estimation of the timing of synostosis, and that more detailed study on the growth pattern of the normal and the synostosed skull could provide prediction of the risk of resynostosis. CLINICAL RELEVANCE STATEMENT: The data from this study can be useful to better understand the cranial growth pattern in patients with craniosynostosis.

Jacob's disease secondary to coronoid process osteochondroma. A case report.

The formation of a new joint between a pathologically elongated coronoid process and the body of the malar homolateral bone is known as Jacob's disease. Coronoid process hyperplasia was first described in 1853 by Von Langenbeck, and it was not until 1899 when Oscar Jacob described the disease that it was named after him. Jacobs's disease is an uncommon entity with only a few documented cases in the literature. The condition first manifests with progressive limitation of mouth opening and facial asymmetry. Pain is uncommon and it mainly affects young patients. Different factors have been postulated as possible causes, including temporal muscle hyperactivity, previous trauma, chronic disc displacement of the ipsilateral temporomandibular joint, endocrine stimuli, and genetic alterations. Definitive diagnosis is by histopathology and it is necessary to confirm bone hyperplasia, the presence of cartilage and synovial capsule forming the new joint between the malar bone and the coronoid process. We report a 52-year-old woman patient with a history of childhood trauma in the right preauricular region. She came to our department with a 2-year history of progressive limitation of mouth opening. Computed tomography (CT) revealed a right coronoid process elongation, in contact with the homolateral malar bone, causing it to deform. Surgery with general anesthesia was performed using an intraoral vestibular approach. Histopathology confirmed the diagnoses of Jacob's disease.