Automated 3-D Computer-Aided Measurement of the Bony Orbit: Evaluation of Correlations among Volume, Depth, and Surface Area.

(1)The study aimed to measure the depth, volume, and surface area of the intact human orbit by applying an automated method of CT segmentation and to evaluate correlations among depth, volume, and surface area. Additionally, the relative increases in volume and surface area in proportion to the diagonal of the orbit were assessed. (2) CT data from 174 patients were analyzed. A ball-shaped mesh consisting of tetrahedral elements was inserted inside orbits until it encountered the bony boundaries. Orbital volume, area depth, and their correlations were measured. For the validation, an ICC was used. (3) The differences between genders were significant (p < 10-7) but there were no differences between sides. When comparing orbit from larger to smaller, a paired sample t-test indicated a significant difference in groups (p < 10-10). A simple linear model (Volume~1 + Gender + Depth + Gender:Depth) revealed that only depth had a significant effect on volume (p < 10-19). The ICCs were 1.0. (4) Orbital volume, depth, and surface area measurements based on an automated CT segmentation algorithm demonstrated high repeatability and reliability. Male orbits were always larger on average by 14%. There were no differences between the sides. The volume and surface area ratio did not differ between genders and was approximately 0.75.

Influence of preoperative anatomy and functional status on outcomes after total temporomandibular joint replacement with patient-specific endoprostheses: A retrospective cohort study.

BACKGROUND: Temporomandibular joint (TMJ) replacement may be indicated for various pathological conditions, and the type of condition can affect the surgical procedure and outcomes. The causes of limited range of motion after alloplastic TMJ replacement have not been extensively studied. OBJECTIVES: The present study aimed to evaluate the impact of preoperative jaw anatomy and functional status on the immediate and long-term outcomes of total TMJ replacement using a two-component patient-specific TMJ endoprosthesis. MATERIAL AND METHODS: This retrospective study included 31 patients who underwent total TMJ replacement surgery between 2016 and 2020. The main outcome variable was the maximal incisal opening (MIO) after treatment. Secondary outcome variables included MIO improvement and the presence and type of postoperative complications. The primary predictive variable was the preoperative initial MIO. Secondary predictive variables included sex, age, indications for TMJ replacement, preoperative occlusion, condition of the glenoid fossa and/or condyle, shortening of the mandibular ramus, sagittal mandible position, lateral chin deviation, shape of the coronoid process, and type of surgery. RESULTS: The mean preoperative MIO was 13.0 ±8.0 mm, while the mean MIO 1 month after surgery was 20.6 ±5.5 mm, which was not statistically significant. However, at a later follow-up, functional parameters showed a significant improvement (p = 0.003), with a mean MIO of 32.5 ±5.0 mm 3 years after surgery. Statistical analysis indicated that the initial mouth opening is the strongest predictor of long-term functional recovery after TMJ replacement. Postoperative complications occurred in 4 cases (12.9%) following patient-specific endoprosthesis (PSE) placement. CONCLUSIONS: The use of PSEs for TMJ replacement has enabled the restoration of anatomical relationships in complex clinical cases and an improvement in mouth opening. The preoperative MIO was the only factor that significantly influenced long-term functional outcomes.

Delayed reconstruction of the combat-related mandibular defects with non-vascularized iliac crest grafts: Defining the optimal conditions for a positive outcome in the retrospective study.

BACKGROUND: Reconstruction of mandibular defects caused by combat injuries is challenging for clinicians due to soft tissue defects and high complication risk. This study evaluated the outcomes of mandibular continuous defects reconstruction with non-vascularized iliac crest graft (NVICG) in patients with combat injuries. MATERIAL AND METHODS: Patients with continuous mandibular defects acquired by high-velocity agents, who received NVICG reconstruction with or without microvascular-free soft tissue or regional flaps, were included in the study. The outcome variable was graft loss due to postoperative complications or full (more than 90 %) resorption. The primary predictor variable was soft tissue defect in the recipient area. The secondary predictor variable was the length of the defect. Variables related to patients, defect site, surgery, and other complications were also evaluated. Statistical analysis was performed with the usage of independent sample t-test, Pearson's chi-squared and Fisher's exact tests with a significance level of P < 0.05 RESULTS: The study included 24 patients with 27 mandibular defects. Overall, the general success rate of reconstructions was 59.3 %. Soft tissue defects were significantly associated with graft failure and other complications (p < 0.05), which were mostly related to soft tissue defects. The graft success rate was only 14.3 % even in minor soft tissue defects. In turn, in reconstructions with sufficient soft tissue coverage, the graft survived in 75.0 % of the cases. In addition, patients with more delayed reconstruction had significantly fewer graft failures than those with earlier surgery (p < 0.05). No associations were found between defect size and complications. CONCLUSION: The sufficient soft tissue coverage is essential in the reconstruction of mandibular defects caused by combat injuries. Also, minor soft tissue defects should be covered with soft tissue flaps to avoid complications and graft loss in these specific injuries. Even large defects can be reconstructed with NIVICG if the soft tissue coverage is sufficient.

Condiciones de aplicación del injerto ilíaco óseo en la sustitución de defectos mandibulares: un estudio retrospectivo de 11 años de experiencia / Conditions of iliac bone grafts application in mandibular defects replacement: a retrospective study of 11-years’ experience

Antecedentes: Este estudio tenía como objetivo aclarar la aparición y las causas de complicaciones postoperatorias en pacientes con defectos mandibulares continuos, reconstruidos con injertos óseos ilíacos libres. Pacientes y métodos: Los pacientes con defecto de continuidad mandibular con pérdida de tejido óseo, que dio lugar a una brecha de 2 cm o más, se sometieron a reconstrucción con injerto óseo de cresta ilíaca no vascularizado. La variable de resultado fue el fracaso del injerto, que se definió como su pérdida por infección postoperatoria, exposición del injerto, reabsorción completa o no unión del injerto. Los factores predictivos fueron el momento de la reconstrucción, la longitud del defecto óseo, la presencia preoperatoria de defecto mucoso y/o dehiscencia y el método de fijación. Todas las variables explicativas y predictoras se analizaron mediante regresión logística binomial univariante.Resultados: El estudio incluyó los resultados de 50 reconstrucciones mandibulares con injerto óseo de cresta ilíaca no vascularizado que se observaron retrospectivamente. El seguimiento de los pacientes incluidos osciló entre 6 meses y 11 años. 34 pacientes (68 %) tuvieron resultados quirúrgicos satisfactorios. En 16 pacientes (32 %) se perdieron los injertos óseos. Todos ellos debido al desarrollo de infección, supuración y/o exposición del injerto durante los primeros 6 meses del periodo de observación. En el análisis univariante, las principales variables predictoras de fracaso fueron el tabaquismo (OR 5,8; IC: 1,48-22,7; p = 0,002), el momento de la reconstrucción (OR 7,94; IC: 1,88-33,5; p = 0,004) y el defecto o dehiscencia de la mucosa (OR 8,49; IC: 2,21-32,6; p = 0,002). El análisis multivariante también reveló la afectación sinfisaria del defecto (OR 5,63; IC: 1,14-27,8; p = 0,034) como factor predictivo significativo de fracaso en un caso de reconstrucción inmediata. ... (AU)

Background: This study aimed to clarify the occurrence and causes of postoperative complications in patients with continuous mandibular defects, reconstructed with free iliac bone grafts.Patients and methods: Patients with mandibular continuity defect with bone tissue loss, resulting in a 2 cm gap or more underwent reconstruction with non-vascularized iliac crest bone graft. The outcome variable was graft failure which was defined as its loss due to the postoperative infection, graft exposure, full resorption or non-unition of the graft. The predictors were timing of reconstruction, length of the bone defect, preoperative presence of mucosa defect and/or dehiscence and fixation method. All explanatory and predictor variables were analyzed with univariate binomial logistic regression.Results: The study included the results of 50 mandibular reconstructions with non-vascularized iliac crest bone graft which were observed retrospectively. The follow-up of included patients ranged from 6 months to 11 years. 34 patients (68 %) had successful surgery results. In 16 patients (32 %) the bone grafts were lost. All of them due to the infection development, suppuration and/or graft exposure during the first 6-months of the observation period. In univariate analysis, the main failure predictor variables were smoking (OR 5.8, CI 1.48-22.7, p = 0.002), timing of reconstruction (OR 7.94, CI 1.88-33.5, p = 0.004) and mucosa defect or dehiscence (OR 8.49, CI 2.21-32.6, p = 0.002). The multivariate analysis also revealed symphyseal involvement of defect (OR 5.63, CI 1.14-27.8, p = 0.034) as the significant failure predictor in a case of immediate reconstruction. The length of defect and fixators type remained statistically non-significant for mandibular reconstruction with NVICG (p < 0.05).Conclusion: ... (AU)

Recurrent Ameloblastoma: Clinical Manifestation and Disease-Free Survival Rate.

Objectives: Ameloblastoma is a slow-growing epithelial odontogenic neoplasm of the jaws with a high recurrence rate. The main treatment strategies for this lesion are radical or conservative surgical approaches. The aim of the present study was to analyze clinical presentations, histological types, and treatment strategies of recurrent ameloblastoma and to define its disease-free survival (DFS) rate. Materials and Methods: Twenty-four cases of recurrent ameloblastomas, treated between January 2009 and July 2021, were enrolled in this study. Medical files from each patient, including gender, age, size of the lesion, localization, patient complaints, clinical manifestation, radiographic appearance, histological type, surgical management, and treatment results were reviewed and analyzed retrospectively. Result: Out of 69 operated primary ameloblastomas, the rate of recurrence was 35%. Out of 24 recurrent cases, 21 developed after conservative treatment and 3 after radical treatment. In most cases, recurrences were found in the mandible (n = 20). A unilocular pattern was predominant in radiographic examination (44%). Estimated 3-year DFS was 84.5 ± 4.8%, and the 5-year and 10-year DFS were 73.0 ± 6.3% and 43.9 ± 8.343.9 ± 8.3%, respectively. Conclusion: Results obtained in the present retrospective study proved the necessity of long-term follow-up after both conservative and radical treatment approaches. The DFS median in our study was 8 years (95% CI 6 years-10 years). For recurrent cases, radical resection with histologically free margins after exact MRI determination of the ameloblastoma border within the soft tissues should be considered as the method of choice to avoid secondary recurrence.

Clinical application of automated virtual orbital reconstruction for orbital fracture management with patient-specific implants: A prospective comparative study.

The aim of the study was to compare automated and manually conducted (slice-by-slice) virtual orbital wall reconstruction in terms of PSI design, manufacture, and clinical application for orbital fracture management. Patients with orbital wall fractures were evaluated for the potential for treatment with PSI, based on automated virtual wall reconstruction; these formed the main group. The surgical outcomes of these main-group patients' treatments were compared with those of the control group, which comprised patients randomly selected for this study, each of whom had the same orbital trauma patterns and were also managed with PSI. However, the control group patients were treated using 'slice-by-slice' virtual orbital reconstruction. Mean volume differences between the intact and reconstructed orbit were 0.65 ± 0.26 cm3 in the main group (n = 23) and 0.57 ± 0.23 cm3 in the control (n = 27; p = 0.837). In both groups, no cases of implant malposition or enophthalmos were detected after surgery. Orbital shape difference was similar for the main group and the control, at -3.3 ± 3.5% and 3.25 ± 2.5%, respectively (p = 0.929). Diplopia was diagnosed at the 3-month follow-up in 13.0% of the main group and in 11.1% of the control (p = 0.651). The average times spent on computer-aided design (CAD) procedures, including segmentation, virtual orbital reconstruction, and PSI design, were 36.7 ± 6.9 min in the main group and 72.9 ± 7.7 min in the control group (p < 0.001). Within the limitations of the study it seems that PSI based on automated virtual reconstruction is a relevant alternative treatment option for orbital fractures because of its clinical efficacy that is similar to PSI based on a 'slice-by-slice' CAD protocol.

The epidemiology and management of ameloblastomas: A European multicenter study.

The present study aimed at assessing the epidemiology including demographic variables, diagnostic features, and management of ameloblastomas at several European departments of maxillofacial and oral surgery. The following data were recorded for each patient: gender, age, voluptuary habits, comorbidities, site, size, radiographic features, type, histopathological features, kind of treatment, length of hospital stay, complications, recurrence, management and complications of the recurrence. A total of 244 patients, 134 males and 110 females with ameloblastomas were included in the study. Mean age was 47.4 years. In all, 81% of lesions were found in the mandible, whereas 19% were found in the maxilla. Mean size of included ameloblastomas was 38.9 mm. The most frequently performed treatment option was enucleation plus curettage/peripheral ostectomy in 94 ameloblastomas, followed by segmental resection (60 patients), simple enucleation (46 patients), and marginal resection (40 patients). A recurrence (with a mean follow up of 5 years) was observed in 47 cases out of 244 ameloblastomas (19.3%). Segmental resection was associated with a low risk of recurrence (p = 0003), whereas enucleation plus curettage/peripheral ostectomy was associated with a high risk of recurrence (p = 0002). A multilocular radiographic appearance was associated with a high risk of recurrence (p < .05), as well as the benign solid/multicystic histologic type (p < .05). Within the limitations of the study it seems that the management of ameloblastomas will probably remain controversial even in the future. Balancing low surgical morbidity with a low recurrence rate is a difficult aim to reach.

Application of Patient-Specific Implants as Alternative Approach to Zygoma Defect Management - A Retrospective Study.

INTRODUCTION: Zygoma defects are a challenging clinical problem and are frequently connected with the alteration of facial harmony, horizontal asymmetry of the face, and significant functional deficit. The application of patient-specific implants (PSIs) has the potential to improve the effectiveness of zygoma defect management. The aim of this study was to evaluate the anatomic, esthetic, and functional outcomes of PSI application for zygoma reconstruction. MATERIALS AND METHODS: A retrospective study was conducted on data from 11 patients with zygoma defects who underwent a reconstruction procedure in which a PSI was applied and was followed for >1 year after surgery with the evaluation of esthetic and functional outcomes. Precision of PSI position and anatomy reconstruction was estimated by superimposition of the models with automatic point-to-point measurement and determination of the existing deviations between models. RESULTS: The mean follow-up period in our study was 21.6 ± 6.2 months (range 14-39 months). No major complications occurred in the postoperative period: There were no clinical or computed tomography symptoms of maxillary sinusitis, implant-related infection, or implant exposure. The mean deviation between the planned and real positions of PSIs in our series was 0.72 ± 0.41 mm. The mean deviation between the reconstructed zygomatic complex and the mirrored intact side in our series was 1.45 ± 0.7 mm. The mean volume difference between the intact and damaged orbits was 1.7 ± 0.8 mm3. DISCUSSION: The results of the present study support the wider clinical application of PSIs in orbital and zygoma reconstructions, as it is an effective option to achieve precise reconstruction of the complex zygoma anatomy.

Controversies in ameloblastoma management: evaluation of decision making, based on a retrospective analysis / Controversias en el manejo del ameloblastoma: Evaluación de la toma de decisiones, basada en un análisis retrospectivo

Background: The ameloblastoma management is still challenging to the high recurrence rates and significantmorbidity associated with radical treatment. The purpose of this 10-year retrospective study was to analyze theinfluence of ameloblastoma type and treatment strategy on the long-term outcomes and recurrence rates.Material and Methods: The retrospective analyses of 64 histologically-confirmed ameloblastoma cases was per-formed. The possible risk factors for recurrence and the development of complications were estimated statistically.Results: The treatment strategy applied for this group of patients was the following: thirty-four patients (53.1%)were treated conservatively with enucleation or extended bone curettage. Radical treatment (bone resection) wasapplied in 30 (46.9%) cases. The follow-up period ranged from 2 to 10 years (mean value 4.28 ± 3,26). General re-currence rate consisted 32.8%. This study did not find significant correlations between clinical or histopathologi-cal features of the ameloblastoma and the recurrence rate. The only factor that significantly influence recurrencerate was the treatment strategy (41% in conservative treatment vs 15% in radical treatment, p<0.05). Postoperativecomplications were observed in 42 patients (65.6%) and included face asymmetry and disfigurement (17.2%), tem-porary paresthesia of the inferior alveolar nerve (IAN) - 23.4%, permanent paresthesia of IAN - 20.3%, paresisof a marginal branch of the facial nerve - 6.3%, infection 12.5%, and swelling - 20.3%. The complication rates,esthetic and functional deficiency were significantly higher in radically treated patients (p<0.05)Conclusions: Our study confirms that higher recurrence rate is associated with conservative treatment for am-eloblastoma, while radical treatment leads to an increased number of postoperative complications that affect thepatient's quality of life.(AU)

Biomechanical evaluation of type p condylar head osteosynthesis using conventional small-fragment screws reinforced by a patient specific two-component plate.

BACKGROUND: The aim of this study was to evaluate via finite element analysis (FEA) the biomechanical behavior of conventional small-fragment screws reinforced by a patient-specific plate in type p condylar head. METHODS: A finite element model of the mandible was created using Mimics 12.1 software. A type p condylar head fracture was simulated in the right condyle, and the left condyle was used as a control. Two patterns of fixation were investigated: conventional two-screw fixation and the same fixation system reinforced with a small, patient-specific plate. Surface models were imported into the software Ansys 5.7for further volume mesh generation. RESULTS: The highest stress gradients were observed in the cortical layer of the lateral fragment, located near the screw. The conventional fixation method resulted in equivalent stresses 2 to 10 times greater than the reinforced method. Rigidity of fixation in the reinforced method increased up to 1.25-3 times compared to the conventional two-screw technique. CONCLUSION: This study's findings suggest significant benefits in unfavorable biomechanical conditions from reinforcement of the standard two-screw fixation of condylar head fractures with a small, patient-specific plate acting as a washer.

Automatic evaluation of the orbital shape after application of conventional and patient-specific implants: Correlation of initial trauma patterns and outcome.

PURPOSE: To evaluate the precision of orbital shape reconstructions using either conventional plates (CPs) or patient-specific implants (PSIs) to treat different types of orbital fractures, and to evaluate their clinical outcomes. METHODS: A total of 92 orbital-reconstruction patients were included. Forty-seven patients, treated with PSIs, formed the main group. The remainder, treated with CPs, were the control group. All patients were examined pre- and postoperatively using computerized tomography (CT) and evaluated for enophthalmos and diplopia. Evaluation of differences in orbital shape between damaged and intact orbits after surgery was performed by commercial orbital analysis software. RESULTS: In the main group, mean orbital shape difference between damaged and intact orbits after surgery was 0.137 ± 0.8 cm3 (range -1.7-2.3 cm3). In the control group, the mean shape difference was 1.05 ± 1.9 cm3 (range -1.8-8.3 cm3), significantly higher (p = 0.007). Diplopia occurred in seven PSI patients three months after surgery (14.9%) and in thirteen CP patients (28.9%) (p = 0.181). Enophthalmos occurred in five PSI patients (10.6%) and in sixteen CP patients (35.6%) (p = 0.001). CONCLUSION: Precise orbital reconstruction prevents the development of enophthalmos after trauma in patients with orbital wall fractures. In patients with preserved infraorbital buttresses and posterior orbital ledges, there were no significant clinical differences between PSIs and CPs. For cases requiring cantilevered reconstruction, including those with zigomatic or maxillary fragment repositioning, preference should be given to the PSI procedure for both effectiveness and predictability.

Application of CAD/CAM technology for surgical treatment of condylar head fractures: A preliminary study.

OBJECTIVES: The aim of the present study was to improve the accuracy and reliability of ORIF in patients with condylar head fractures (CHFs) by developing a design for patient specific fixators, navigation and repositioning guides, as well as the algorithms of their clinical application. MATERIALS AND METHODS: 14 patients with 16 CHFs were treated by ORIF with the use of CAD/CAM technology. After virtual reduction of the bony fragments, the appropriate length and diameter of the screws was chosen. In biomechanically unfavorable cases (type p) patient specific reinforcement plates were used together with the positional screws for reinforcement of the bone-fixator system. And in cases of severely comminuted fractures patient specific 3-D plate was applied. RESULTS: The CT data, obtained immediately after the operation revealed the good anatomical reduction. Any deviations of the small fragments noted were near 1 mm in all cases. Postoperative clinical examination at 3 months follow up showed good occlusion and mouth opening not less than 3 cm in all patients. The lateral and anterior mobility of the mandible was restored with small limitations of protrusive mobility in 1 case. All the patients were satisfied with the outcomes. CONCLUSIONS: The application of the CAD/CAM technologies and the new design of the surgical guides and patient specific reinforcement plates for CHFs helps to improve the accuracy and quality of fragments reduction and stability of fixation with minimal risks of intraoperative complications. CLINICAL RELEVANCE: CAD/CAM technologies improve the clinical effectiveness of treatment patients with the CHFs.

Reliability of orbital volume measurements based on computed tomography segmentation: Validation of different algorithms in orbital trauma patients.

PURPOSE: To compare the most common methods of segmentation for evaluation of the bony orbit in orbital trauma patients. MATERIALS AND METHODS: Computed tomography scans (before and after treatment) from 15 patients with unilateral blowout fractures and who underwent orbital reconstructions were randomly selected for this study. Orbital volume measurements, volume difference measurements, prolapsed soft tissue volumes, and bony defect areas were made using manual, semi-automated, and automated segmentation methods. RESULTS: Volume difference values between intact and damaged orbits after surgery using the manual mode were 0.5 ± 0.3 cm3, 0.5 ± 0.4 cm3 applying semi-automated method, and 0.76 ± 0.5 cm3, determined by automated segmentation (р = 0.216); the mean volumes (MVs) for prolapsed tissues were 3.0 ± 1.9 cm3, 3.0 ± 2.3 cm3, and 2.8 ± 3.9 cm3 (p = 0.152); and orbital wall defect areas were 4.7 ± 2.8 cm2, 4.75 ± 3.1 cm2, and 4.9 ± 3.3 cm2 (p = 0.674), respectively. CONCLUSIONS: The analyzed segmentation methods had the same accuracy in evaluation of volume differences between two orbits of the same patient, defect areas, and prolapsed soft tissue volumes but not in absolute values of the orbital volume due to the existing diversity in determination of anterior closing. The automated method is recommended for common clinical cases, as it is less time-consuming with high precision and reproducibility.

Clinical efficacy of peek patient-specific implants in orbital reconstruction.

PURPOSE: To assess the clinical efficacy of custom made PEEK patient-specific implants in treatment of orbital wall defects. METHODS: Forty-five patients with unilateral post-traumatic orbital wall defects were enrolled in the study. They underwent subsequent reconstructive procedures using PEEK patient-specific implants (PSI) or pre-bent titanium plates. All the patients were examined with the standardized algorithm, including local status examination, vision assessment and computer tomography (CT) with measurements of the orbital volume. A comparative analysis of the treatment outcomes in two groups of patients (pre-bent plates/PSI) was performed. RESULTS: The study findings show an absence of any postoperative infection, inflamation or decreased visual acuity in either group. In PSI group, diplopia after surgery was absent in 82.1% of patients versus 70.6% of controls. The mean duration of surgery was 54.25 ± 16.8 min with PSI application and 82.9 ± 10.8 min with pre-bent plates. The mean difference between the intact and damaged orbital volume was 1.9 ± 1.4 cm3 in the control group versus 0.74 ± 0.6 cm3 in PSI group (р<0.05). CONCLUSION: PEEK PSI demonstrated higher clinical efficacy in comparison to pre-bent plates in orbital wall reconstruction especially in restoring the volume and shape of the damaged orbit.