Comparing the characteristics of recurrent versus primary odontogenic keratocysts - A single center retrospective cohort study.

The high recurrence rate of odontogenic keratocysts (OKC) entails a large number of follow-up interventions after primary surgery. This study aimed to compare recurrent with primary OKC in regard to recurrence rate, treatment modality, radiographic and clinical findings. A single center retrospective cohort study with surgically treated OKC between 2012 and 2021 was conducted. The primary predictor was recurrence type of the lesion: primary (P-OKC), first recurrence (R1-OKC) and second recurrence (R2-OKC). The primary outcome variables were recurrence and time to recurrence. 68 surgeries were identified. Recurrence was not significantly associated with recurrence type (p = 0.906) but with the method of surgery (p < 0.001). Marsupialized R1-OKC recurred earlier than marsupialized P-OKC. Diameter was significantly associated with recurrence type (p = 0.002). R1-OKC had a smaller median diameter than P-OKC and R2-OKC were smaller than R1-and P-OKC. P-OKC were associated with teeth in 79% of surgeries, R1-OKC in 61% and R2-OKC in 27% (p = 0.007). Postoperative numbness was present after 40% of surgeries and decreased to 15% at follow-up, independently of recurrence type. Time to recurrence may be shorter for recurrent marsupialized OKC. Recurrent OKC are smaller and less often associated with teeth. Postoperative numbness after OKC surgery has a good prognosis.

[Conspicuous Conditions of the Tongue: Normal Variants vs. Pathological Findings].

INTRODUCTION: With its sensitivity, taste buds and complex anatomical structure of various muscles, the tongue is a central organ for speaking, tasting and food intake, especially oral food transport, chewing and swallowing. Changes in the tongue 's condition are frequent and often lead to uncertainty among patients and eventually to a visit to the family doctor, to the ear, nose and throat specialist, dentist or maxillofacial surgeon. The question whether the condition of the tongue is a lesion requiring treatment or just a variant can quite often prove a major challenge. The differential diagnoses are wide-ranging from harmless changes to alarming signs of disease. The time and duration of occurrence, the accompanying symptoms such as a burning sensation or taste disorders as well as risk factors such as nicotine and alcohol consumption are important anamnestic elements. Possible causes can be malnutrition, systemic diseases, inflammatory processes or malignancies. Accordingly, a blood test and a smear or a biopsy may be necessary as the first diagnostic step. The aim of this review is to explain the different types and causes of tongue problems and to explain in which cases further clarifications are necessary.

Radioactive nanosized colloids and indocyanine green identify the same sentinel lymph nodes in oral squamous cell carcinoma.

PURPOSE: Near-infrared fluorescence imaging using indocyanine green (ICG) combined with radioactive markers has the potential to improve sentinel lymph-node (SLN) mapping in oral squamous cell carcinoma (OSCC). This study aimed to evaluate the ability of 99mTc and ICG in identifying the sentinel lymph nodes in patients with early stage OSCC. METHODS: Data were collected prospectively, and a retrospective analysis of 15 patients with early stage OSCC and a cN0 neck was performed. All patients received peritumoral injection of 99mTc the day before surgery and ICG was administered intraoperatively. Intentionally, the application of the two different tracers were done by two different physicians with varying degrees of experience. The number of identified lymph nodes positive for 99mTc and ICG, the overlap or possible discrepancies of both methods, and the time until fluorescence signals of ICG were detected were noted. RESULTS: In all patients, a 100% agreement in sentinel lymph-node identification was achieved, regardless of both the exact location of the peritumoral injection and the experience of the injecting surgeon. Time until ICG accumulation in the sentinel lymph node was consistently found to be between 1 and 3 min. CONCLUSION: ICG constitutes a viable and useful addition to 99mTc for intraoperative sentinel lymph-node detection in this study.

Retrospective comparison of one-stage and two-stage orbital reconstruction in patients suffering from combined injuries of the midface.

Reconstruction of the bony orbit in patients with combined midface injuries is frequently discussed in the current literature. Two main concepts can be distinguished: single-stage reconstruction, usually with a hand-bent titanium orbital mesh, and two-stage reconstruction, in which osteosynthesis of the zygomaticomaxillary complex (ZMC) is followed by orbital reconstruction with a virtually-planned, patient-specific titanium implant in a second surgery. This study aimed to compare one-stage and two-stage surgical approaches on combined midface fractures regarding postoperative diplopia. A total of 58 patients treated with one-stage (n = 29) or two-stage (n = 29) reconstruction of the ZMC and orbit were included, and their postoperative course over five months was retrospectively analysed. A descriptive quantitative analysis of the course of occurrence of diplopia was recorded to calculate the success of orbital repair in complex midface fractures including the orbit. The two workflows differed in the prevalence of postoperative clinical diplopia and eyelid complications. Multiple factors affect the decision whether or not to reconstruct the orbit first, and in the same intervention as the associated midface fracture. Thorough evaluation of each individual patient with a patient-specific choice of surgical concept is crucial, and includes multiple factors.

Need for adjuvant radiotherapy in oral cancer: depth of invasion rather than tumor diameter.

PURPOSE: The 8th edition of the TNM Cancer Staging Manual incorporates depth of invasion (DOI) into the pathologic tumor classification for oral squamous cell carcinoma (OSSC). While deep invading tumors with small tumor diameters (TD) have been categorized as early stage tumors in the 7th edition, they are now upstaged, potentially influencing the decision to initiate adjuvant radiotherapy (RT). METHODS: OSCC patients surgically treated with curative intent between 2010 and 2019 were consecutively included. Tumors were staged based on TD only (according to the 7th edition TNM Cancer Staging Manual), then restaged based solely on DOI. RESULTS: Of the 133 included patients, 58 patients (43.6%) had a different pT-stage when using DOI instead of TD for staging (upstaging in 23.3%). Overall survival (OS) was significantly worse in patients who were upstaged with DOI. In addition, stratification by adjuvant RT showed significant worse OS in upstaged patients without receiving adjuvant RT. CONCLUSIONS: DOI seems to be an import indicator for adjuvant RT in OSCC-patients.

Meeting Quality Metrics in Oral Squamous Cell Carcinoma Surgery: A Single-Center Experience.

Patient-centered quality metrics have been proposed to evaluate and optimize hospital processes, aiming to improve patient outcomes. Furthermore, they can be used to objectively rate and compare the ability of health care providers to meet the needs of their patients. In patients with advanced resectable oral squamous cell carcinoma, optimal surgical treatment of the neck and timely initiation of both surgical and adjuvant therapy, when indicated, are crucial for recurrence-free and overall survival. This retrospective analysis included 160 patients who received primary resection of oral squamous cell carcinoma and concurrent neck dissection. It aimed to investigate how well quality metrics were met during a 6-year period in the department of oral and maxillofacial surgery at a university hospital. 93.1% of patients were seen in the specialist's office within 21 days after referral. Resection was classified as R0 in 94.4%. A lymph node yield ≥ 18 was achieved in 82.5%. The lymph node ratio was ≤6% in 43.3% of nodal-positive necks. Readmission and unplanned revision surgery were rare (6.9%). Adjuvant radiotherapy was started ≤ 6 weeks after surgery in 45.3%, and the indication was in accordance with international guidelines in all cases. Quality metrics are an effective tool for planning process optimization in a hospital. Moreover, nodal quality metrics such as lymph node yield and lymph node ratio could, after validation, complement existing and well-established prognostic parameters for patient-specific adaptation of adjuvant treatment plans.

[A radiolucent rarity - primary intraosseous mucoepidermoid carcinoma of the posterior mandible: From radiographic incidental finding to molecular pathological diagnosis]. / Eine radioluzente Rarität ­ Primär intraossäres Mukoepidermoidkarzinom des posterioren Unterkiefers: vom röntgenologischen Zufallsbefund zur molekularpathologischen Diagnose.

We report the case of a 64-year-old patient with incidental finding of a unilocular radiolucency in the posterior mandible on an apical radiograph. The biopsy (cystostomy) revealed the unusual finding of a primary intraosseous mucoepidermoid carcinoma; this is with 2­4% of ectopic manifestations of this entity a rarity. Molecular pathological analysis with a specific panel (SalvGlandDx) and FISH provided diagnosis-confirming evidence of the specific CRTC1-MAML2 fusion. Box resection, prophylactic osteosynthesis using a patient-specific reconstruction plate, neck dissection, and local coverage using a Bichat flap were performed according to the interdisciplinary tumor board decision. With tumor-free lymph nodes and R0 resection, adjuvant therapy was not required. Clinical and imaging follow-up over 24 months showed no evidence of locoregional recurrence. The presented case report emphasizes the central role of private dental practices in the early detection of oral malignancies. These should always be considered in the differential diagnosis of cystic lesions.

Visualization of Inferior Alveolar and Lingual Nerve Pathology by 3D Double-Echo Steady-State MRI: Two Case Reports with Literature Review.

Injury to the peripheral branches of the trigeminal nerve, particularly the lingual nerve (LN) and the inferior alveolar nerve (IAN), is a rare but serious complication that can occur during oral and maxillofacial surgery. Mandibular third molar surgery, one of the most common surgical procedures in dentistry, is most often associated with such a nerve injury. Proper preoperative radiologic assessment is hence key to avoiding neurosensory dysfunction. In addition to the well-established conventional X-ray-based imaging modalities, such as panoramic radiography and cone-beam computed tomography, radiation-free magnetic resonance imaging (MRI) with the recently introduced black-bone MRI sequences offers the possibility to simultaneously visualize osseous structures and neural tissue in the oral cavity with high spatial resolution and excellent soft-tissue contrast. Fortunately, most LN and IAN injuries recover spontaneously within six months. However, permanent damage may cause significant loss of quality of life for affected patients. Therefore, therapy should be initiated early in indicated cases, despite the inconsistency in the literature regarding the therapeutic time window. In this report, we present the visualization of two cases of nerve pathology using 3D double-echo steady-state MRI and evaluate evidence-based decision-making for iatrogenic nerve injury regarding a wait-and-see strategy, conservative drug treatment, or surgical re-intervention.

Proximity of the middle meningeal artery and maxillary artery to the mandibular head and mandibular neck as revealed by three-dimensional time-of-flight magnetic resonance angiography.

PURPOSE: The close topographic relationship between vascular and osseous structures in the condylar and subcondylar region and marked variability in the arterial course has been revealed by both imaging and cadaveric studies. This study aimed to verify the previously published information in a large sample and to determine a safe surgical region. METHODS: We analyzed the three-dimensional time-of-flight magnetic resonance angiography images of 300 individuals. RESULTS: The mean distance between the middle meningeal artery and the apex of the condyle or the most medial point of the condyle was 18.8 mm (range: 11.2-25.9 mm) or 14.5 mm (range: 8.8-22.9 mm) respectively. The course of the maxillary artery relative to the lateral pterygoid muscle was medial in 45.7% of cases and lateral in 54.3%. An asymmetric course was evident in 66 patients (22%). The mean distance between the maxillary artery and condylar process at the deepest point of the mandibular notch was 6.2 mm in sides exhibiting a medial course (range: 3.7-9.8 mm) and 6.6 mm in sides exhibiting a lateral course (range: 3.9-10.4 mm). The distances were significantly influenced by age, gender, and the course of the maxillary artery. CONCLUSION: Our study emphasizes the marked inter- and intra-individual variability of the maxillary and middle meningeal arterial courses. We confirmed the proximity of the arteries to the condylar process. Extensive surgical experience and thorough preparation for each individual case are essential to prevent iatrogenic vascular injury.

Volumetric Evaluated Bone Resorption After Open Reduction and Internal Fixation of Condylar Head Fractures of the Mandible.

PURPOSE: Decision making in the management of condylar head fractures remains difficult due to its dependency on multiple factors like fracture type, degree of dislocation, patient`s age and dental condition. As open reduction and internal fixation (ORIF) of condylar head fractures (CHFs) becomes more popular, the question of osteosynthesis removal is controversial. So far, information on volumetric changes after ORIF are available for a short-term period (<6 months) only. This study, therefore, was performed to assess bone resorption after condylar head fractures and to follow-up intermediate-term (>1 year) remodelling after removal of metallic osteosynthesis material. Furthermore clinical outcome was measured using Helkimo Index and put in relation with bone resorption. MATERIALS AND METHODS: A retrospective analysis of 19 patients who underwent open reduction and internal fixation of condylar head fractures at the University Hospital of Zürich between January 2016 and April 2018 using intraoperative cone-beam computed tomography repositioning control was conducted. The bone resorption on the condylar head was measured in the course after removal of osteosynthesis material by segmenting and superimposing of the postoperative 3D radiologic follow-up exam (T2) over the initial intraoperative cone-beam computed tomography (T1) using iPlan-CMF software. Complementary Helkimo index was assessed to put resorption rate in relation to clinical outcome. RESULTS: A total of 19 patients fulfilled the inclusion criteria. The mean follow-up time was 15.6 months and the mean bone resorption on the condylar head was -0.348cm3 or -15.29% of segmented condylar head. There was no correlation of clinical outcome and bone resorption. CONCLUSIONS: Helkimo index showed satisfying results; therefore, ORIF of condylar head fracture proves as a feasible treatment option. The mean bone resorption rate of -15.29% in the intermediate-term follow-up time (mean 15.6 months) is comparable to findings of other studies with short-term follow-up time (< 6 months). Thus, postinterventional remodeling activity and resorption seems highest in the first 4 to 6 postoperative months with little further resorption. In prevention of negative sequelae of protruding implants, timing of osteosynthesis material removal after this period of high bone remodeling activity is recommended. The resorption rate showed no correlation to clinical outcome.

ASA score and procedure type predict complications and costs in maxillofacial reconstructive surgery: a retrospective study using a hospital administrative database.

BACKGROUND: Reconstruction of osseous and soft tissue defects after surgical resection of oral cavity cancers can be achieved by a single-stage procedure with a microvascular bone flap or by a two-step approach with a soft tissue flap and subsequent bone augmentation. The therapeutic approach should be selected based on the patient’s needs. Economic pressure requires preoperative risk assessment and estimation of the postoperative course. Flat-rate reimbursement systems via diagnosis-related groups with insufficient morbidity adjustments and financial sanction of medical complications might additionally cause false incentives in the choice of treatment. OBJECTIVE: This study aimed to assess the influence of the type of flap chosen for maxillofacial reconstructive surgery on the total costs. Complication rates of different types of flap surgery and their prediction by a preoperative risk assessment tool (American Society of Anesthesiologists [ASA] score) were determined. Overall, the fairness of the current reimbursement system was rated. METHODS: Patient characteristics, clinical data, and data on total costs and reimbursement of patients aged 18 years and older having undergone maxillofacial reconstructive flap surgery at the University Hospital of Zurich (Switzerland) between 2012 and 2014 were analysed. The preoperative risk was classified by the ASA score. Complications were graded according to the Clavien-Dindo classification system and the comprehensive complication index (CCI). Statistical analysis included Spearman and Pearson rank correlation, Kruskal-Wallis and Mann-Whitney nonparametric tests, and linear regression analysis. RESULTS: 129 patients were included in this study. Soft tissue flaps were performed in 82 patients, of which 56 were radial forearm flaps (43.4%), bone flaps in 41 patients, of which 32 were fibula flaps (24.8%), and combined flaps in 6 patients (4.7%). Patients with fibula flaps showed a significantly higher CCI and higher total costs. Higher preoperative ASA scores were significantly associated with increased length of stay, total costs and complications. Both the ASA score and reconstruction with a radial forearm flap were significant predictors of complications and total costs. Total median costs for radial forearm flaps were CHF 50,560 (reimbursement: CHF 60,851; difference: CHF 10,291) and for fibula flaps CHF 66,982 (reimbursement: CHF 58,218; difference: CHF −8,764). CONCLUSION: The ASA score allows a reliable preoperative assessment of patient outcomes and financial burden in maxillofacial reconstructive flap surgery. The type of flap reconstruction significantly influences complications and ultimately total costs. The current reimbursement system via diagnosis-related groups (DRGs) does not take sufficient account of this fact. Adaptations are therefore needed to prevent misplaced incentives to the detriment of patients.

Surgical Outcomes of Orbital Fracture Reconstruction Using Patient-Specific Implants.

PURPOSE: Patient-specific implants (PSIs) are known to yield reliable outcomes in orbital wall fracture reconstruction (high precision, smoother operating techniques, and shorter surgical duration). This study analyzed the surgical error and clinical and esthetic outcomes of orbital reconstructions with PSIs. METHODS: This ambispective cohort study enrolled patients who underwent orbital reconstruction using PSIs between October 2016 and January 2018. The study end points were surgical error, indication and duration of surgery, long-term sequelae, revision surgeries, and surgical complications. Surgical error was analyzed by superimposing the postoperative implant position onto the preoperative virtual plan. Both qualitative (heat map) and quantitative (distance) measurements were obtained. RESULTS: Three patients were enrolled prospectively, and 23 were enrolled retrospectively. Indications for surgery were defect size (25 patients), diplopia (10 patients), impaired eye motility (4 patients), and significant enophthalmos (6 patients). At the last patient visit, there were 5 cases of diplopia, 1 case of exophthalmos, and 6 cases of slight enophthalmos of incremental degree. In terms of surgical error, a mean distance of 0.6 mm (95% confidence interval, 0.49 to 0.76), with a mean maximal distance of 3.4 mm (95% confidence interval, 2.79 to 4.02), was noted. No revision surgery was necessary. Lid malposition complications were not observed. However, 1 case each of symblepharon and scleral show were observed. No time-saving component was observed. CONCLUSIONS: PSI use in orbital reconstruction guarantees a preplanned 3-dimensional anatomical shape with a mean surgical error of just 0.6 mm. Our clinical results were similar to those of other protocols; however, warranting a complex 3-dimensional anatomical shape also in large orbital fractures with a low mean surgical error is feasible by using PSIs.

Customized Titanium Reconstruction of Orbital Fractures Using a Mirroring Technique for Virtual Reconstruction and 3D Model Printing.

PURPOSE: Early operative reconstruction using titanium mesh is a technique often used for preventing sequelae after an orbital fracture. We sought to examine the utility of patient-specific molding of the mesh with a biomodel via virtual mirroring of the nonaffected side. METHODS: We retrospectively assessed the clinical and radiological outcomes of orbital fracture reconstruction using a customized titanium mesh shaped on 3D-printed biomodels in 34 unilateral orbital fracture cases. Preoperative virtual orbital reconstruction images, using the mirroring technique, were superimposed on postoperative 3D images, and clinical data from patient charts were analyzed. Orbital reconstructions were rated, and the intention to revise results intraoperatively, or during inpatient or outpatient phases, was assessed by 2 consultants and 2 residents. RESULTS: We found that most fractures arose from falls of <3 meters or from interpersonal violence. Ophthalmic injuries included subconjunctival bleeding, ocular contusion, enophthalmos, and diplopia. Long-term sequelae at last followup were diplopia (8.8%) and mild enophthalmos (11.8%). CONCLUSION: Interrater reliabilities regarding consultants' intention to revise results were substantial to almost perfect at any time point. Therefore, using the mirroring technique for the virtual reconstruction of a fractured orbit and a 3D-printed biomodel to customize commercial titanium implants yields good and reliable results, enhances surgical precision, and decreases the need for intraoperative revision, as well as long-term sequelae of orbital fractures.

Cell seeding accelerates the vascularization of tissue engineering constructs in hypertensive mice.

Rapid blood vessel ingrowth into transplanted constructs represents the key requirement for successful tissue engineering. Seeding three-dimensional scaffolds with suitable cells is an approved technique for this challenge. Since a plethora of patients suffer from widespread diseases that limit the capacity of neoangiogenesis (e.g., hypertension), we investigated the incorporation of cell-seeded poly-L-lactide-co-glycolide scaffolds in hypertensive (BPH/2J, group A) and nonhypertensive (BPN/3J, group B) mice. Collagen-coated scaffolds (A1 and B1) were additionally seeded with osteoblast-like (A2 and B2) and mesenchymal stem cells (A3 and B3). After implantation into dorsal skinfold chambers, inflammation and newly formed microvessels were measured using repetitive intravital fluorescence microscopy for 2 weeks. Apart from a weak inflammatory response in all groups, significantly increased microvascular densities were found in cell-seeded scaffolds (day 14, A2: 192 ± 12 cm/cm2, A3: 194 ± 10 cm/cm2, B2: 249 ± 19 cm/cm2, B3: 264 ± 17 cm/cm2) when compared with controls (A1: 129 ± 10 cm/cm2, B1: 185 ± 8 cm/cm2). In this context, hypertensive mice showed reduced neoangiogenesis in comparison with nonhypertensive animals. Therefore, seeding approved scaffolds with organ-specific or pluripotent cells is a very promising technique for tissue engineering in hypertensive organisms.

Radiologic Analysis of Surgically Treated Fractures of the Condylar Process by an Endoscopic-Assisted Transoral Approach.

PURPOSE: This study analyzed the radiologic outcomes of patients with unilateral mandibular condylar fractures treated with open reduction-internal fixation (ORIF) through a transoral approach. PATIENTS AND METHODS: In this retrospective study, the radiologic images of 40 patients who underwent open reduction-internal fixation through a transoral approach were presented to 2 independent examiners. All patients underwent the surgical procedure between January 2015 and December 2016 at the Department of Cranio-Maxillofacial Surgery at UniversitätsSpital Zürich and were included in a previous functional outcome study. The surgical results were analyzed and graded as poor, acceptable, or good. The examiners declared whether they would have made any intraoperative revisions if the radiologic information had been available. Finally, the examiners estimated the required duration of elastic intermaxillary fixation (IMF) from the radiologic images, which was compared with the actual duration. RESULTS: Fracture reduction was classified as good in 33 cases (82.5%), acceptable in 5 cases, and poor in 2 cases by one examiner and as good in 32 cases (80%), acceptable in 6 cases, and poor in 2 cases by the other examiner. The inter-rater reliability was determined to be good (Cohen κ = 0.92). Correct osteosynthesis placement was found in 19 cases by one examiner and in 21 cases by the other examiner, with good inter-rater reliability (κ = 0.8). Moderate inter-rater reliability (κ = 0.4) was found for the required duration of elastic IMF. Furthermore, the estimated elastic IMF duration matched the actual duration in fewer than half of the cases. CONCLUSIONS: It is feasible to achieve reliably good radiologic results when operating on condylar process fractures by a transoral approach with endoscopic assistance and angled instruments. Intraoperative 3-dimensional imaging enables instant quality control and prompts surgical revision if needed.

Associated Ophthalmic Injuries in Patients With Fractures of the Midface.

PURPOSE: Concomitant ophthalmic injuries are common in patients with facial fractures, though frequency varies widely in the literature. Major ophthalmic injuries can have drastic consequences for patients, and permanent visual impairment cannot be prevented in all cases. This study analyzed the frequency and distribution pattern of associated ophthalmic injuries in patients who received operative treatment for fractures of the midface. MATERIAL AND METHODS: The clinical information system was searched for patients with midface fractures that were treated operatively between December 2014 and November 2017. Demographic, fracture-related, and ophthalmic data were assessed and statistically analyzed. RESULTS: This study included 282 patients. The most common fracture types were zygomaticomaxillary complex fractures and orbital floor fractures. Falls and violence were the most common causes of fractures (43.3% and 24.5%, respectively). Chemosis and subconjunctival bleeding were the most common associated eye injuries. The most prevalent long-term eye injury was diplopia, which was identified in 18.4% of cases preoperatively. Postoperative diplopia persisted in 36 cases (12.8%) at 3-month follow-up. Optic neuropathy, enophthalmos, exophthalmos, and retrobulbar hematomas were identified infrequently. CONCLUSION: Minor ophthalmic injuries, including chemosis and subconjunctival bleeding, are more frequently associated with midface trauma. These minor injuries tend to heal quickly and without sequela. Major ophthalmic injuries, including retinal detachment, optic neuropathy, and retrobulbar hematomas, are identified less frequently. Special attention should be paid to patients with diplopia, as this condition may persist and have long-term occupational consequences. Therefore, close interdisciplinary collaboration is essential when treating patients with fractures of the midface to prevent permanent visual impairment.

Does Zygomatic Complex Symmetry Differ Between Healthy Individuals and Surgically Treated Patients Using Intraoperative 3-Dimensional Cone Beam Computed Tomographic Imaging?

PURPOSE: Reconstruction of symmetry after zygomaticomaxillary complex (ZMC) fractures is essential for esthetic appearance as well as function. Therefore, this study aimed to analyze whether bony facial symmetry in patients surgically treated for unilateral ZMC fractures via intraoperative imaging differs from that of healthy individuals. PATIENTS AND METHODS: Retrospective and cross-sectional radiographic measurements of patients treated for unilateral ZMC fractures via intraoperative cone beam computed tomography (CBCT) were performed to evaluate the postoperative ZMC symmetry. The same number of healthy individuals without any history of midfacial trauma matched for age and gender served as the control group. Asymmetry of the ZMC was determined by measuring bilateral differences in the malar eminence position on CBCT. In addition, demographic statistics, etiology, and fracture type were analyzed. RESULTS: Analysis of 57 surgically treated patients and 57 healthy individuals with a mean age of 29 years was performed. No significant difference in the symmetry of the malar eminence position was observed between healthy individuals and patients treated for a unilateral ZMC fracture (P = .890). In one third of patients, corrections were needed after intraoperative CBCT control. CONCLUSIONS: The results of this study indicate that, on average, a ZMC asymmetry of 1.6 mm is observed in healthy individuals. Furthermore, the use of intraoperative CBCT for the treatment of dislocated ZMC fractures helps to achieve precise anatomic, symmetrical repositioning and is suggested to improve the quality of care.

Improved Results in Closed Reduction of Zygomatic Arch Fractures by the Use of Intraoperative Cone-Beam Computed Tomography Imaging.

PURPOSE: The use of intraoperative imaging could help overcome the insufficiency of closed reduction that can result from the absence of visible feedback to evaluate the accuracy of the reduction in isolated zygomatic arch fractures. The aim of the present study was to evaluate the use of intraoperative 3-dimensional cone-beam computed tomography (CBCT) to improve the accuracy of reduction, by measuring the remaining cortical step and dislocation angle. We also evaluated the effect of CBCT on the need for repeat surgery. PATIENTS AND METHODS: We performed a retrospective cohort study of patients who had undergone zygomatic arch reduction surgery from January 2008 to May 2018. The patients were grouped according to the predictor variables into group A (postoperative radiologic follow-up studies) and group B (intraoperative CBCT imaging studies). The primary outcome variables were the remaining cortical step and dislocation angle compared with the ideal virtually mirrored position. These were assessed as measures of reduction accuracy. The secondary variables included age, gender, surgery duration, and fracture type. Statistical analysis was performed using a robust multiple regression analysis. RESULTS: The 45 patients were divided into 2 subgroups with 18 patients in the no intraoperative imaging (control) group and 27 patients in the intraoperative imaging group. Insufficient reduction occurred in 1 patient in the group without intraoperative imaging, leading to repeat surgery. No repeat surgery was necessary in the intraoperative imaging group. The remaining cortical step of the intraoperative imaging group was significantly lower than that of the control group (0.18 vs 2.03 mm; P < .001). For the remaining dislocation angle, similar findings were observed but without statistical significance (3.93° vs 7.75°; P = .58). CONCLUSIONS: The use of intraoperative CBCT significantly increased the accuracy of the reduction. Furthermore, the need for repeat surgery was not required for any patient in the intraoperative imaging group with CBCT-guided reduction.

Accuracy of Computer-Guided Template-Based Implant Surgery: A Computed Tomography-Based Clinical Follow-Up Study.

OBJECTIVE: The aim of this clinical study was to analyze the accuracy of computer-guided implant surgery. MATERIALS AND METHODS: Assisted by computed tomography (CT)-based planning software and navigational templates, 16 patients successfully received 26 dental implants. Each implant parameter (a-d) was calculated based on superimposed preoperative and postoperative cone beam CT scans: (a) deviation at entry point; (b) deviation at apex; (c) angular deviation; and (d) depth deviation. RESULTS: Mean central deviation at implant entry point and apex was 0.91 mm (standard error [SE] = 0.11 mm; 95% confidence interval [CI]: 0.69-1.13) and 1.22 mm (SE = 0.11 mm; 95% CI: 0.99-1.45), respectively. Mean angulation deviation was 4.11 degrees (SE = 0.52 degrees; 95% CI: 3.04-5.17) and the average depth deviation was 0.65 mm (SE = 0.11 mm; 95% CI: 0.42-0.87). For the total number of implants placed, the maximum error was 2.34 mm at entry point, 2.71 mm at apex, 9.44 degrees in angular deviation, and 2.00 mm in depth deviation. CONCLUSION: Great accuracy was reached even in advanced cases with prior bone augmentation and complex traumas. This leads to the conclusion that particularly in advanced cases, computer-guided implantation can be beneficial.