Zygomatic Arch Research Articles

Anatomical Identification and Possibilities of Transfer of the Masseteric Nerve for Facial Reanimation

The masseteric nerve (MN) is often used as a donor nerve for facial reanimation. In addition to already established techniques, MN transfer is rapidly gaining importance, mainly due to the single-stage approach of the procedure and its reconstructive potential. This anatomical study and the associated questionnaire study aimed to evaluate the established methods for identification of the MN and its suitability for direct nerve transfer as well as to assess the importance of MN transfer in the daily clinical routine. Bilateral dissection of 25 fresh-frozen head specimens (n=50; 13 female, 12 male) was performed with accompanying measurement of the MN. In a questionnaire study conducted at established centres for facial surgery in German-speaking countries, clinical experience data of MN transfer was collected using the SurveyMonkey software. The data obtained was statistically analysed using Microsoft Excel and presented in numerical tables and boxplots. Using anatomical landmarks such as the zygomatic arch and the mandibular notch for orientation, the MN was found in 100% of cases. Its average length from the emerging point below the zygomatic arch towards its entry into the masseter muscle was measured to be 22 mm and was the length available for nerve transposition. Tension-free coaptation of the MN with the zygomatic branch was possible in 94% of cases. The questionnaire showed that the MN is considered an important donor nerve for motor nerve transfers and that MN transfer is now largely established as a standard procedure. In accordance with previously published studies, the MN was reliably found at the height of the mandibular notch and, in the vast majority of cases, was suitable for tension-free coaptation with the zygomatic branch. Differences to the existing literature, however, can be seen in the length of the nerve available for nerve transposition and the frequency of its division into several branches before entering the masseter muscle. In German-speaking countries, Cross-Face Nerve Grafting (CFNG) is still the preferred method for facial reanimation surgery. However, MN transfer is also well established by now, both as an alternative and a supplement to other techniques, possibly due to its low donor site morbidity and short time to regeneration.

Management of Atypical M-Shaped Zygomatic Arch Fractures.

M-shaped zygomatic arch fractures can usually be treated effectively through closed reduction. It consists of 2 fracture segments: the anterior zygomatic segment and the posterior temporal bone segment. In clinical practice, atypical M-shaped fractures are often encountered, in which the anterior and posterior fracture segments are discontinuous and separated. Closed reduction usually cannot achieve the desired anatomic reduction effect for this type of fracture. The preoperative design showed that the anatomic reduction of the posterior zygomatic arch fracture segment was hindered due to bone spurs in the most concave area of the anterior zygomatic bone fracture segment. Open reduction and fixation were performed to achieve anatomic reduction and restore facial symmetry. The fracture sites were exposed through a hemicoronal incision. After the bone spurs are removed, the posterior bone segment can be anatomically reduced. Absorbable plates were used for fixation. The patient's facial appearance was restored after the surgery. The postoperative computed tomography scan showed a good alignment of the fracture. The authors believe that for patients with high requirements for facial symmetry, the presence of atypical M-shaped fractures can indicate open reduction and fixation.

Extended reduction malarplasty for Asians with flat and wide face: Comparison with L-shaped osteotomy.

Reduction malarplasty is effective in correcting prominent zygomatic body and arch in Asian populations, but periorbital zygomatic bony protrusion may not be sufficiently improved. In this study, we present the extended reduction malarplasty procedures to correct it simultaneously and compare the outcome with that of conventional L-shaped osteotomy. A retrospective review of consecutive patients who received reduction malarplasty between August 2021 and September 2023 at our hospital was conducted. Computed tomography images obtained before and after surgery were assessed to evaluate the facial skeletal changes, and to compare between the extended and conventional L-shaped malarplasty results. Twenty extended reduction malarplasty patients and 23 conventional reduction malarplasty patients were eligible for the study. Cephalometric analyses showed significant reduction in the zygomatic width in both groups, but the protrusion of the periorbital area was improved significantly greater in the extended reduction malarplasty group. In terms of facial angulation, the extended reduction malarplasty also provided more horizontal convexity in the periorbital area, whereas the angular change in the caudal part of zygoma was not significantly different. The extended reduction malarplasty enabled to reduce the protrusion of the periorbital area, as well as the prominent zygomatic body and arch, and provided more three-dimensionality and horizontal convexity with the midface contour. It is a viable option for harmonizing the facial profile for Asian patients with flat and wide face.

Transmalar Kirshner Wire Fixation Under Ultrasound Scanning is Useful for Unstable Zygomatic Arch Fracture Combined With Zygomatic Body Fracture.

Plate fixation to zygomatic arch fractures carries the risk of facial nerve palsy and scarring of the cheek; however, without plate fixation, bone deviation or displacement may reoccur after surgery. Furthermore, zygomatic arch fractures combined with zygomatic body fractures are more postoperatively unstable than single zygomatic arch fractures. Few reports have focused on this combined fracture type, and no consensus has been reached regarding treatment. Because plate fixation for slight deviation of the zygomatic body has little advantage for stabilization, the authors, usually opt for transmalar pinning alone instead of plate fixation at the hospital. This study is a retrospective case series of 7 patients, among 100 zygomatic fractures excluding isolated zygomatic arch fractures, treated using transmalar pinning under ultrasound scanning. The reduction was performed through the oral and temporal incision as a surgical procedure. Under ultrasound observation, a Kirshner wire was inserted into the zygomatic body from the unaffected side while maintaining the reduced position. The wire was removed at an outpatient visit 2 to 3 months following surgery. In all cases, the zygomatic body was of the laterally rotated type, and postoperative morphologic evaluation showed improvement without postoperative complications. Scores were higher in middle-aged and older than in young people. Correction of zygomatic rotation also scored higher than zygomatic arch morphology. Transmalar Kirshner wire fixation under ultrasound observation is a simple and minimally invasive method for zygomatic arch fractures, which avoids the possible complications related to plate fixation.

Detection and Classification of Human Gender into Binary (Male and Female) Using Convolutional Neural Network (CNN) Model

This paper focuses on detecting the human gender using Convolutional Neural Network (CNN). Using CNN, a deep learning technique used as a feature extractor that takes input photos and gives values to various characteristics of the image and differentiates between them, the goal is to create and develop a real-time gender detection model. The model focuses on classifying human gender only into two different categories; male and female. The major reason why this work was carried out is to solve the problem of imposture. A CNN model was developed to extract facial features such as eyebrows, cheek bone, lip, nose shape and expressions to classify them into male and female gender, and also use demographic classification analysis to study and detect the facial expression. We implemented both machine learning algorithms and image processing techniques, and the Kaggle dataset showed encouraging results.

Development and growth of the temporal fascia: a histological study using human fetuses.

The temporal fascia is a double lamina sandwiching a thick fat layer above the zygomatic bony arch. To characterize each lamina, their developmental processes were examined in fetuses. We observed histological sections from 22 half-heads of 10 mid-term fetuses at 14-18 weeks (crown-rump length, 95-150 mm) and 12 near-term fetuses at 26-40 weeks (crown-rump length, 215-334 mm). The superficial lamina of the temporal fascia was not evident at mid-term. Instead, a loose subcutaneous tissue was attached to the thin, deep lamina of the temporal fascia covering the temporalis muscle. At near-term, the deep lamina became thick, while the superficial lamina appeared and exhibited several variations: i) a mono-layered thick membrane (5 specimens); ii) a multi-layered membranous structure (6) and; iii) a cluster of independent thick fasciae each of which were separated by fatty tissues (1). In the second and third patterns, fatty tissue between the two laminae was likely to contain longitudinal fibrous bands in parallel with the deep lamina. Varying proportions of the multi-layered superficial lamina were not attached to the zygomatic arch, but extended below the bony arch. Whether or not lobulation or septation of fatty tissues was evident was not dependent on age. The deep lamina seemed to develop from the temporalis muscle depending on the muscle contraction. In contrast, the superficial lamina developed from subcutaneous collagenous bundles continuous to the cheek. Therein, a difference in development was clearly seen between two categories of the fasciae.

The ‘Manchester’ method of minimal access fixation of the zygomatic arch in zygomatic complex fractures: a case series

We have introduced a minimally invasive approach for the fixation of the zygomatic arch during the surgical management of zygomatic complex fractures. Access for this technique is provided by a preauricular approach and eyelid incisions with the addition of transcutaneous stab incisions overlying the arch. These stab incisions allow transcutaneous drilling and screw placement through a size CH 20 (5.0 mm) paediatric nasopharyngeal airway (NPA). We present a case series of seven patients. In all patients the arch component was successfully reduced and fixed, and no intraoperative or postoperative complications were observed. The use of an NPA is novel. It functions as a flexible self-irrigating sleeve and protects the skin from mechanical and thermal damage. The technique uses readily available equipment, is easy to learn, and simplifies surgery to the zygomatic arch.

Consideration of the diameter of superficial temporal arteries related to filler injections in the temporal region.

The concavity of the temple due to adipose tissue atrophy from aging accentuates the zygomatic arch and lateral orbital rim, leading to an aged appearance. The use of hyaluronic acid filler in the temporal region has gained popularity due to its procedural simplicity and consistent outcomes. To evaluate the safety of administering hyaluronic acid filler in the temporal region concerning the frontal branch of the superficial temporal artery, which is at risk of injury. Empirical observations were conducted on the internal diameter of the frontal branch of the superficial temporal artery, a critical anatomical site for potential injury. A significant proportion of the artery segments exhibited an internal diameter below 1 mm. Given that the outer diameter of an 18-gauge cannula is 1.27 mm, this method can be considered a relatively secure approach for enhancing the temporal region. The use of an 18-gauge cannula for hyaluronic acid filler administration in the temporal region appears to be a safe and effective method, with the potential risk to the frontal branch of the superficial temporal artery being minimal.

TOPOGRAPHIC AND ANATOMICAL PECULIARITIES OF THE LATERAL REGION OF THE HEAD IN HUMAN FETUSES

HEAD IN HUMAN FETUSESAbstract. In order to clarify the topographical and anatomical peculiarities and variant anatomy of the structures of the lateral region of the head in the fetal period of human ontogenesis, 24 specimens of human fetuses aged from 4 to 10 months of intrauterine development were studied using a complex of morphological research methods (anthropometry, macroscopy, computer tomography, morphometry, reconstruction). We found anatomical variants of the masseter and temporal muscles in human fetuses. Thus, in a 5-month-old fetus, separate muscle bundles were found, which went from the right masseter to the right temporal muscle. In a 6-month-old fetus, the deep part of the left masseter muscle was fused to the left temporal muscle. In human fetuses, the temporal fascia in the direction of the zygomatic arch splits into two layers, between which there are accumulations of adipose tissue. In late fetuses, a formed sub-aponeurotic fi brous space was found. At the end of the fetal period, a deep fi brous space is observed between the periosteum and the inner edge of the temporal muscle. The cellular spaces of the temporal area in front are connected with the buccal fat pad, which creates the prerequisites for the spread of infl ammatory processes. The topographic and anatomical features of the temporal region of human fetuses are: weak development of the temporal muscle and small depth of the temporal fossa – in the middle part from 3.0 to 6.0 mm (depending on the age of the fetus); weakly developed tendinous part of the temporal muscle, which does not reach the temporal line of the parietal bone. The bony base of the temporal area is represented by the squamous part of the temporal bone, the greater wing of the sphenoid bone, part of the parietal and frontal bones, on the inner surface of which arterial grooves and impressions of cerebral gyri are hardly visible, and sometimes not at all clear or absent. Anatomical variants of the structure of the temporal and masticatory muscles, as well as the temporal fascia, can cause complications and errors during the diagnosis and surgical treatment of infl ammatory processes in the postnatal period of human ontogenesis.

Evaluation of Different Fixation Methods Combinations After L-Shaped Osteotomy Reduction Malarplasty: An In Vitro Biomechanical Study.

This in vitro study compared the stability of different fixation method combinations for the zygomatic complex after simulated L-shaped osteotomy reduction malarplasty, a common facial contouring surgery in East Asia with high postoperative complications due to poor fixation methods. The study used 108 zygoma replicas with various fixation methods combinations in the zygomatic body (L-shaped plate with short wing on zygoma and on the maxilla, two bicortical screws, one bicortical screw with L-shaped plate, square plate, and rectangular plate) and zygomatic arch (Mortise-Tenon structure, 3-hole plate, and Mortise-Tenon structure plus short screw). The failure force under incremental load was applied through the Instron tensile machine to a well-stabilized model using a rubber band simulating the masseter muscle and recorded the increasing force digitally. ANOVA test was used for comparison between recorded values (P < 0.05). The results showed that the most stable combination was a six-hole rectangular plate and a Mortise-Tenon structure plus one short screw (358.55 ± 51.64 N/mm2). The results also indicated that the placement vector of the fixation methods around the L-shaped osteotomy and the use of the two-bridge fixation method were important factors in enhancing the stability of the zygomatic complex. The study suggested that surgeons should choose appropriate fixation methods based on these factors to reduce postoperative complications and improve surgical outcomes. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. 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 .

Microanatomical Investigation of the Subtemporal Transtentorial Approach

To study the microanatomic structure of the subtemporal transtentorial approach to the lateral side of the brainstem, and to provide anatomical information that will assist clinicians to perform surgeries on the lateral, circumferential, and petroclival regions of the brainstem. Anatomical investigations were conducted on 8 cadaveric head specimens (16 sides) using the infratemporal transtentorial approach. The heads were tilted to one side, with the zygomatic arch at its highest point. Then, a horseshoe incision was made above the auricle. The incision extended from the midpoint of the zygomatic arch to one third of the mesolateral length of the transverse sinus, with the flap turned towards the temporal part. After removing the bone, the arachnoid and the soft meninges were carefully stripped under the microscope. The exposure range of the surgical approach was observed and the positional relationships of relevant nerves and blood vessels in the approach were clarified. Important structures were photographed and the relevant parameters were measured. The upper edge of the zygomatic arch root could be used to accurately locate the base of the middle cranial fossa. The average distances of the star point to the apex of mastoid, the star point to the superior ridge of external auditory canal, the anterior angle of parietomastoid suture to the superior ridge of external auditory canal, and the anterior angle of parietomastoid suture to the star point of the 10 adult skull specimens were 47.23 mm, 45.27 mm, 26.16 mm, and 23.08 mm, respectively. The subtemporal approach could fully expose the area from as high as the posterior clinoid process to as low as the petrous ridge and the arcuate protuberance after cutting through the cerebellar tentorium. The approach makes it possible to handle lesions on the ventral or lateral sides of the middle clivus, the cistern ambiens, the midbrain, midbrain, and pons. In addition, the approach can significantly expand the exposure area of the upper part of the tentorium cerebelli through cheekbone excision and expand the exposure range of the lower part of the tentorium cerebelli through rock bone grinding technology. The total length of the trochlear nerve, distance of the trochlear nerve to the tentorial edge of cerebellum, length of its shape in the tentorial mezzanine, and its lower part of entering into the tentorium cerebelli to the petrosal ridge were (16.95±4.74) mm, (1.27±0.73) mm, (5.72±1.37) mm, and (4.51±0.39) mm, respectively. The cerebellar tentorium could be safely opened through the posterior clinoid process or arcuate protrusion for localization. The oculomotor nerve could serve as an anatomical landmark to locate the posterior cerebral artery and superior cerebellar artery. Through microanatomic investigation, the exposure range and intraoperative difficulties of the infratemporal transtentorial approach can be clarified, which facilitates clinicians to accurately and safely plan surgical methods and reduce surgical complications.

The L-Shaped Zygomatic Reduction with Oblique or Vertical Resection: Which One Is the Optimal Choice?

This study aimed to investigate the optimal surgical techniques in reduction malarplasty by comparing the difference between the L-shaped osteotomy with vertical and oblique bone resection. A total of 120 patients who visited the authors' department for L-shaped osteotomy with either vertical (group I) or oblique bone resection (group II) from 2015 to 2021 were reviewed retrospectively. The preoperative and postoperative spiral computed tomographic data were analyzed. The preoperative computed tomographic data were also used to simulate the virtual and model surgery. The results showed that a broken bridge-like structure with a bony gap of 2.86 ± 1.03 mm at the zygomatic arch root was observed in group I, and a mortice-and-tenon joint structure with a bone overlap of 2.28 ± 0.58 mm was formed in group II. The zygoma in group I displaced significantly in the vertical direction and horizontal direction during the follow-up. Simultaneously, the incidence of complications was higher in group I. In the mechanism analysis through virtual and model surgery, the zygomatic segment was shifted anteriorly and inferiorly in group I, and a bony gap was detected at the zygomatic arch root. Conversely, a superior and posterior movement was performed in group II and it maintained the zygomatic complex integral with bone overlap at the zygomatic arch root on repositioning. This study suggested that L-shaped osteotomy with oblique bone resection could be the optimal choice for reducing zygomatic prominence. Therapeutic, III.

Functionally mediated cranial allometry evidenced in a genus of rock-wallabies.

In assessments of skeletal variation, allometry (disproportionate change of shape with size) is often corrected to examine size-independent variation for hypotheses relating to function. However, size-related trade-offs in functional demands may themselves be an underestimated driver of mammalian cranial diversity. Here, we use geometric morphometrics alongside dental measurements to assess craniodental allometry in the rock-wallaby genus Petrogale (all 17 species, 370 individuals). We identified functional aspects of evolutionary allometry that can be both extensions of, and correlated negatively with, static or ontogenetic allometric patterns. Regarding constraints, larger species tended to have relatively smaller braincases and more posterior orbits, the former of which might represent a constraint on jaw muscle anatomy. However, they also tended to have more anterior dentition and smaller posterior zygomatic arches, both of which support the hypothesis of relaxed bite force demands and accommodation of different selective pressures that favour facial elongation. By contrast, two dwarf species had stouter crania with divergent dental adaptations that together suggest increased relative bite force capacity. This likely allows them to feed on forage that is mechanically similar to that consumed by larger relatives. Our results highlight a need for nuanced considerations of allometric patterns in future research of mammalian cranial diversity.

The Spatial Relationship Between Coronoid Process and Zygomatic Complex After Reduction Malarplasty.

Reduction malarplasty presents challenges in terms of postoperative complications, particularly limited mouth opening. Excessive inward displacement of the zygomatic complex can impinge on the coronoid process resulting in restricted mouth opening. This study aimed to assess the spatial relationship between the coronoid process and the zygomatic complex after reduction malarplasty. A retrospective study was conducted, including consecutive patients underwent reduction malarplasty. Radiological measurements were performed before surgery and during the final follow-up, including the coronoid-condylar index, distance between the coronoid process and zygomatic complex, and thickness and density of the temporal and masseter muscles. Clinical and radiographic data were recorded and analyzed. A total of 159 female patients were included with an average age of 28.1 years and a mean follow-up of 6.7 months. The mean coronoid-condylar index was 1:1.4, ranging from 1:0.6 to 1:2.6. Following surgery, the distances between the coronoid process and the anterior zygoma decreased by approximately 1 mm. Additionally, the postoperative distance between the highest point of the coronoid process and the zygomatic arch decreased by around 4 mm horizontally and changed approximately 1 mm vertically. No significant changes were observed in the thickness and density of the temporal and masseter muscles after surgery. Reduction malarplasty led to a slight decrease in the distance between the coronoid process and the zygoma. The operation generally resulted in proximity between the highest point of the coronoid process and the zygomatic arch. However, we believe that common reduction malarplasty rarely leads to osseous impingement. 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.

Major clinical and surgical approaches to treating orbitozygomatic and zygomatic maxillary complex fractures: a systematic review

Introduction: In the scenario of orbitozygomatic fractures, facial and head injuries account for half of deaths due to trauma, and thousands are left with long-term or permanent injuries. Fractures of the zygomatic-maxillary complex (ZMC) and zygomatic arch are common athletic injuries. Operative treatment is indicated in cases of significant displacement or functional disturbance. Technology such as virtual surgical planning, intraoperative navigation, and intraoperative imaging has the potential to improve the accuracy of treatment of challenging fractures. Objective: It was to develop a systematic review of the main clinical and surgical approaches to the treatment of orbitozygomatic and zygomatic maxillary complex fractures. Methods: The PRISMA Platform systematic review rules were followed. The search was carried out from October 2023 to January 2024 in the Scopus, PubMed, Science Direct, Scielo, and Google Scholar databases. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: A total of 102 articles were found, 26 articles were evaluated in full and 25 were included and developed in the present systematic review study. Considering the Cochrane tool for risk of bias, the overall assessment resulted in 14 studies with a high risk of bias and 12 studies that did not meet GRADE and AMSTAR-2. Most studies did not show homogeneity in their results, with X2=57.9%&gt;50%. A single-piece fracture of the fronto-orbito-zygomatic-maxillary bone connected to a temporoparietal bone may require additional osteotomy to achieve successful results in an acute setting. Orbital volume analysis offers a valid modality for objectively evaluating the efficiency of the management of orbitozygomatic complex fractures. The success rate of the fixation procedure at 1 point of the zygomaticomaxillary complex is high, with minimal complications. Intraoperative CT/three-dimensional imaging should be used in the treatment of ZMC fractures requiring orbital floor reconstruction, where adjacent fractures require fixation and/or when ≥ 2 axes are displaced ≥ 5 mm.

Is Gillies Temporal Incision Necessary to Successfully Reduce Zygomaticomaxillary Fracture Combined With Orbital Wall Fracture?

Gillies temporal approach has been widely used to reduce zygoma fractures. Traditionally, it is the preferred method to reduce the isolated zygomatic arch fracture. It can be combined with other approaches, such as subciliary and intraoral incisions for more complex zygomatic fractures, so-called tripod fractures. In this study, the author hypothesized that complex zygomaticomaxillary bone fracture reduction can successfully be achieved without Gillies temporal incision. The author retrospectively analyzed the medical records and 3D facial Computed Tomography (CT) scans of 80 patients who had orbitozygomaticomaxillary fractures that affected >3 sites among the frontozygomatic suture, zygomaticomaxillary buttress, zygomatic arch, and orbital walls from May 2021 to August 2023. A single surgeon performed all surgical operations. All fractures were reduced with 2 incisions, lower eyelid incisions (subciliary or subconjunctival) and intraoral incisions (gingivobuccal approach), within a week of the initial traumatic event. After sufficient exposure to fractured sites using 2 incisions, the author reduced the fracture with a bony hook at the inferior orbital rim, lateral wall, or Boise elevator at the intraoral incision. All cases were successfully corrected without any complications. In conclusion, the author can successfully reduce complex zygomaticomaxillary fracture combined with orbital wall fractures without temporal Gillies approach.

Craniodental ontogenetic variation in the leontiniid coquenia bondi Deraco, Powell, & López, 2008 (Notoungulata, Toxodontia) from the Eocene of Northwestern Argentina

ABSTRACT Craniodental ontogenetic analyses on notoungulates are scarce. Several well-preserved specimens of the Eocene species Coquenia bondi allow for the first ontogenetic study in a Palaeogene leontiniid notoungulate. We studied five almost complete skulls of C. bondi representing three different ontogenetic stages. Cranial ontogeny indicates negative allometry for most of the variables related to the brain and sense organs, with thicker postorbital constriction and braincase breadth in juveniles. The rostrum grows isometrically in length, with positive allometry in height and negative in anterior width. Isometry is recovered for the palatal length and the upper postcanine length, both variables correlated with the longitudinal growth of the splanchnocranium. Other ontogenetic difference is the stouter and sigmoid zygomatic arch in adults, with its posterior root shifted dorsally accompanying the modification of the basicranial angle. Cranial growth of C. bondi is similar to that of Nesodon imbricatus, sharing four coefficients with close values. Molar eruption sequence is anteroposterior, whereas the deciduous premolars are substituted posteroanteriorly. In the juvenile, dentine in M2 is already exposed on the occlusal surface before wear, but the enamel covers the entire crown in m2 of the advanced juvenile.

Evaluation of Zygomaticomaxillary Complex Fractures with Gillies Approach in Al-Baha Region of Saudi Arabia: A Cohort Study.

The aim of this study was to evaluate the accuracy of the degree of fracture reduction after open reduction and internal fixation of Zygomaticomaxillary Complex (ZMC) fractures in the Saudi population of the Al-Baha region, using Gillies approach. Further comparison with preoperative and postoperative standardized computed tomography (CT) views with the calculation of residual deformity percentage, which remained after the ZMC rehabilitation. A 5-year retrospective CT-based study on preoperative and postoperative axial CT scans of 46 male patients with ZMC fractures. The CT measurements were made (in millimeters) at the fracture site of maximum displacement through the anterior orbital rim and orbital floor, posterolateral wall of the maxillary sinus, zygomatic arch, and zygomaticofrontal suture. For the zygomatic arch, measurements were made (in mm) by drawing a tangent to the fractured arch segments and dropping a perpendicular to the inward displaced fractured arch. The total difference in all measured parts between preoperative and postoperative displacement was calculated in percentages. Upon comparison of preoperative and postoperative zygomaticomaxillary complex CTs, three-point fixation at the regions of infraorbital rim, frontozygomatic suture, and posterolateral wall of the maxilla results in a reduction of the fracture sites in the range of 72.85% to 85%. Maximum reduction was noted at the zygomatic arch, that is, 85%, and minimum at the infraorbital rim, that is, 72.85%. The reduction obtained at all four sites was statistically significant, with P values ranging from .011 to .039. Gillies temporal approach and three-point fixation at the regions of the infraorbital rim, frontozygomatic suture, and posterolateral wall of the maxilla results in satisfactory treatment of ZMC fractures and improves patients oral health and quality of life.

Evaluation of the Relationship Between Zygomatic Arch Fracture Reduction and Mandibular Movements.

The aim of this study was to evaluate the relationship between surgical zygomatic arch fracture reduction and mandibular movements in different fracture types. Fractures were classified according to the Yamamoto classification. The extent of zygomatic arch reduction after surgery was evaluated by measuring three reference points on both fractured and normal side both before and after surgery. The selected reference points were: the most anterior (A1), the most posterior (B1) and the midpoint (C1) relative to midsagittal plane on the fracture side and the same points on the normal side (a1, b1, c1). Mouth opening, movements to right and left were recorded in these patients. The highest extent of zygomatic arch reduction was observed at the midpoint of the arch (p = 0.041). Surgery did not significantly alter other points of the zygomatic arch. The extent of reduction of the zygomatic arch was not significantly associated with mandibular movements. However, type of fracture correlated with lateral excursion to the right and left (p = 0.002 and p = 0.031, respectively). This study showed that the amount of post-surgical changes in zygomatic arch reduction was not significantly related to mandibular movements. In addition, the amount of lateral excursion two weeks after surgical correction of more severe types of zygomatic arch fractures was less compared with other fracture types. Patients with more severe fractures may need to be followed for a longer period of time in order to regain the normal mandibular movement range.

A Novel Method in Restoring Form and Function Following Malunited Isolated Zygomatic Arch Fractures- A Technical Note

Isolated zygomatic arch fractures of the facial skeleton are rare. Blunt force to the cheek can result in an isolated zygomatic arch fracture, with resulting aesthetic issues such as indendations and functional impairments such as trismus. Symptomatic or visible isolated zygomatic arch fractures are commonly treated using either the Keen (intraoral) or Gillies (temporal) approaches to reduce the fracture while avoiding visible scars. Typically, the reduced fractures are not rigidly fixated but rather held in place by the native periosteal sleeve. However, cold fractures of the zygomatic arch are difficult to treat as they require a wide area of exposure for re-osteotomy and fixation. In the present technical note, we describe a novel technique to overcome this. Through a minimally invasive approach, two osteotomies were made proximally and distally to the fracture segment, and the segment was rolled 180 degrees along the sagittal axis. The medially depressed zygomatic arch is now projected laterally and was found to give adequate prominence and relieve restrictions in mouth opening. This is a novel method for reestablishing the prominence of the zygomatic arch and aiding in mandibular function following malunion of the fractured, isolated zygomatic arch.