Virtual planning for mandible resection and reconstruction.

In mandibular reconstruction, computer-assisted procedures, including virtual surgical planning (VSP) and additive manufacturing (AM), have become an integral part of routine clinical practice. Especially complex cases with extensive defects after ablative tumor surgery benefit from a computer-assisted approach. Various CAD/CAM-manufactured tools such as surgical guides (guides for osteotomy, resection and predrilling) support the transition from virtual planning to surgery. Patient-specific implants (PSIs) are of particular value as they facilitate both osteosynthesis and the positioning of bone elements. Computer-based approaches may be associated with higher accuracy, efficiency, and superior patient outcomes. However, certain limitations should be considered, such as additional costs or restricted availability. In the future, automation of the planning process and augmented reality techniques, as well as MRI as a non-ionizing imaging modality, have the potential to further improve the digital workflow.

New insights into redox-related risk factors and therapeutic targets in oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is the most common cancer in the oral cavity accounting for 90 % of oral cancer with a global incidence of 350.000 new cases per year. Curative resection along with adjuvant radiation therapy or a combination of radiotherapy with chemotherapy remain as gold standard in treating OSCC. Still, local recurrence, lymph nodal recurrence, and complications of radiation remain the main cause of tumor-related mortality. Reactive oxygen species are not only correlated to the etiology of OSCC due to oxidative DNA damage, lipid peroxidation or effecting signal transduction cascades that effect cell proliferation and tumorigenesis, but are also of great interest in the therapy of OSCC patients. As induced oxidative stress can be used therapeutically for the induction of tumor cell death, redox targets might be a therapeutic addition to the conventional treatment options. In this review, we discuss markers of impaired redox homeostasis as well as potential redox-related treatment targets in OSCC.

Comparison of histopathological margins after resection of oral squamous cell carcinoma using sharp dissection versus mono-polar electrocautery in T1 and T2 tumors.

The study aims to compare histopathological margins after resection of oral squamous cell carcinoma (OSCC) with different surgical techniques: conventional sharp resection (SR) with scalpel versus monopolar electrocautery (ME). Hence, the question arises whether thermal damage by performing monopolar electrocautery surgery will lead to close margins more frequently than by using scalpels. 152 patients were included in this study. All patients received a primary tumor resection either performed with SR or with ME. Surgical margins were distributed into two groups: ≥5 mm (clear margins) and < 5 mm (close or involved margins). For comparing homogeneous groups, we considered tumor localizations, diameter and depth of invasion. The results were statistically analyzed by applying the Wilcoxon-Mann-Whitney-U-Test. The distribution of tumor diameter and depth of invasion was equal in both groups. There was no statistically significant difference between the amount of free surgical margins using SR or ME (p = 0.884). According to this study, the use of the monopolar electrocautery for tumor resection in the oral cavity does not increase the rate of compromised resection margins compared to the conventional scalpel.

Metastases of OSCC Based on Oral Lichen Ruber Planus.

Oral lichen ruber planus (OLP) is a poorly understood chronically inflammatory disease of the oral mucosa. Malignant transformation into oral squamous cell carcinoma (OSCC) is reported in between 1-2% of cases in the literature. After malignant transformation, surgical treatment-meaning tumor resection combined with neck dissection-is recommended. The recommended extent of treatment is controversial in the literature because this kind of OSCC is often a highly differentiated tumor with a lower risk for lymph nodal spreading. This study aims to overview 103 patients treated in our department due to OLP. The primary outcome parameter was the development of metastases in OLP patients compared to a group of OSCC patients without OLP and the comparison of survival in between both groups. Statistical analysis showed a significantly lower risk for patients with OSCC and with OLP for lymph nodal spreading (p = 0.013). Patients with OSCC and without OLP had a 4.76-higher risk for lymph nodal spreading. On the other hand, second metachronous tumor occurred more often in patients with OSCC and OLP. Overall, OSCC based on OLP occurs more often in female patients, is more highly differentiated and comes with a lower risk for metastases but has a higher risk for second metachronous tumors. Therefore, special attention should be paid to patients with OSCC based on OLP when planning adjuvant therapy and clinical follow-up. The indication for postoperative radiation should be made cautiously in this case, and clinical controls should be performed more closely due to the risk of recurrent disease or tumors at different locations.

Comparison of alternative N-staging models in patients with oral cancer. Is nodal yield or burden the most critical parameter?

BACKGROUND: There is increasing evidence in the literature that alternative N-classification systems offer a simpler and more precise risk stratification than the current N- classification in patients with oral squamous cell carcinoma. The purpose of this study is to compare three broadly proposed models incorporating lymph node ratio, log odds of positive lymph nodes and number of positive lymph nodes regarding disease-free and overall survival. METHODS: This is a retrospective study of patients treated in a single center between 2013 and 2019. Cox proportional hazard models, Kaplan Meier curves, the long rank test and the area under the curve were implemented to compare the risk-stratification ability of the three models. Moreover, a hazard ratio plot was calculated to investigate the association between nodal yield and disease-free survival. RESULTS: 231 patients were included. All three proposed N-models were significantly correlated to the patient's prognosis in the multivariate analysis. Pairwise comparisons between the groups showed that the current pN classification offers the worst stratification and that the model incorporating the number of positive lymph nodes had a better performance for predicting both endpoints. Finally, a decrease in hazard ratio was observed with each additional lymph node removed up to the number of 39 lymph nodes. CONCLUSIONS: The model incorporating the nodal burden offered a better predictive ability. The current N-classification cannot adequately identify patients with different prognosis. A non-linear relationship was found between nodal yield and survival, which could be the disadvantage of the lymph node ratio and log odds models.

Accuracy of maxillary positioning using computer-designed and manufactured occlusal splints or patient-specific implants in orthognathic surgery.

OBJECTIVE: To determine the accuracy of maxillary positioning using computer-designed and manufactured occlusal splints or patient-specific implants in orthognathic surgery. MATERIAL AND METHODS: A retrospective analysis of 28 patients that underwent virtually planned orthognathic surgery with maxillary Le Fort I osteotomy either using VSP-generated splints (n = 13) or patient-specific implants (PSI) (n = 15) was conducted. The accuracy and surgical outcome of both techniques were compared by superimposing preoperative surgical planning with postoperative CT scans and measurement of translational and rotational deviation for each patient. RESULTS: The 3D global geometric deviation between the planned position and the postoperative outcome was 0.60 mm (95%-CI 0.46-0.74, range 0.32-1.11 mm) for patients with PSI and 0.86 mm (95%-CI 0.44-1.28, range 0.09-2.60 mm) for patients with surgical splints. Postoperative differences for absolute and signed single linear deviations between planned and postoperative position were a little higher regarding the x-axis and pitch but lower regarding the y- and z-axis as well as yaw and roll for PSI compared to surgical splints. There were no significant differences regarding global geometric deviation, absolute and signed linear deviations in the x-, y-, and z-axis, and rotations (yaw, pitch, and roll) between both groups. CONCLUSIONS: Regarding accuracy for positioning of maxillary segments after Le Fort I osteotomy in orthognathic surgery patient-specific implants and surgical splints provide equivalent high accuracy. CLINICAL RELEVANCE: Patient-specific implants for maxillary positioning and fixation facilitate the concept of splintless orthognathic surgery and can be reliably used in clinical routines.

Chronic Periodontal Infection and Not Iatrogenic Interference Is the Trigger of Medication-Related Osteonecrosis of the Jaw: Insights from a Large Animal Study (PerioBRONJ Pig Model).

Background and Objectives: Antiresorptive drugs are widely used in osteology and oncology. An important adverse effect of these drugs is medication-induced osteonecrosis of the jaw (MRONJ). There is scientific uncertainty about the underlying pathomechanism of MRONJ. A promising theory suspects infectious stimuli and local acidification with adverse effects on osteoclastic activity as crucial steps of MRONJ etiology. Clinical evidence showing a direct association between MRONJ and oral infections, such as periodontitis, without preceding surgical interventions is limited. Large animal models investigating the relationship between periodontitis and MRONJ have not been implemented. It is unclear whether the presence of infectious processes without surgical manipulation can trigger MRONJ. The following research question was formulated: is there a link between chronic oral infectious processes (periodontitis) and the occurrence of MRONJ in the absence of oral surgical procedures? Materials and Methods: A minipig large animal model for bisphosphonate-related ONJ (BRONJ) using 16 Göttingen minipigs divided into 2 groups (intervention/control) was designed and implemented. The intervention group included animals receiving i.v. bisphosphonates (zoledronate, n = 8, 0.05 mg/kg/week: ZOL group). The control group received no antiresorptive drug (n = 8: NON-ZOL group). Periodontitis lesions were induced by established procedures after 3 months of pretreatment (for the maxilla: the creation of an artificial gingival crevice and placement of a periodontal silk suture; for the mandible: the placement of a periodontal silk suture only). The outcomes were evaluated clinically and radiologically for 3 months postoperatively. After euthanasia a detailed histological evaluation was performed. Results: Periodontitis lesions could be induced successfully in all animals (both ZOL and NON-ZOL animals). MRONJ lesions of various stages developed around all periodontitis induction sites in the ZOL animals. The presence of MRONJ and periodontitis was proven clinically, radiologically and histologically. Conclusions: The results of this study provide further evidence that the infectious processes without prior dentoalveolar surgical interventions can trigger MRONJ. Therefore, iatrogenic disruption of the oral mucosa cannot be the decisive step in the pathogenesis of MRONJ.

Lymph nodal recurrence in levels IV and V in oral squamous cell carcinoma after neck dissection.

BACKGROUND: The aim of the study was to determine the risk of lymph node recurrence in levels IV and V after tumour resection and neck dissection of level I-III and level I-V. METHODS: Data from 228 patients suffering from OSCC were analysed retrospectively. Patients with level I-III neck dissection were compared to those with level I-V neck dissection in terms of number and location of nodal recurrence. The incidence of level IV-V recurrence in patients who had received level I-III neck dissection was compared with that of patients who had received level I-V neck dissection. The incidence of level IV-V recurrence was also compared between patients with pN0 and pN+ necks. RESULTS: Overall, 19 patients developed metastases. Only in two cases appeared nodal recurrence in levels IV or V. There was no statistically significant difference between both groups. CONCLUSIONS: Neck dissection of levels I-III seems to be sufficient treatment in cases of unsuspicious lymph nodes in levels IV and V, even in cases of positive nodes in levels I-III if adjuvant radiation therapy is applied. However, 5-year-disease free survival rate is lower in patients with nodal metastases in levels IV and V than in patients with metastases located in levels I-III.

Monopolar electrocautery versus sharp dissection in the neck dissection: a retrospective study.

The cold scalpel/scissors (CS) and the monopolar electrocautery (ME) are still the most commonly used instruments for neck dissection in head and neck oncology. However, a direct comparison of these techniques does not exist. This study aims to compare these techniques concerning blood loss, the decline of hemoglobin levels, and surgery duration. Data on 200 patients who received tumor resection, neck dissection and either a radial forearm free flap (RFFF)or a primary closure (PC) were examined retrospectively. The patients were divided according to the performed defect closure (RFFF or PC) and the main instrument usedfor the beck dissection (Group 1: RFFF and ME, Group 2: RFFF and CS, Group 3: PC and ME Group 4: PC and CS). The intraoperative blood loss, decline of hemoglobin values and surgery duration were analyzed and compared between the corresponding groups. The patients where the ME was used lost on average 409.93 ml (group 1 vs. 2) and 242.4 ml (group 3 vs. 4) less blood. The median decrease in the hemoglobin levels was by 1.01 g/dL (group 1 vs. 2) and 0.85 g/dL (group 3 vs. 4) lower for the ME. The median surgery duration was by 102 min (group 1 vs. 2) and 83 min (group 3 vs. 4) shorterfor the ME. All differences were statistically significant. Traditional scalpel and scissors used for neck dissection lead to significantly higher blood loss and longer operation time than the monopolar electrocautery.

Nodal Disease and Survival in Oral Cancer: Is Occult Metastasis a Burden Factor Compared to Preoperatively Nodal Positive Neck?

The impact of neck involvement and occult metastasis (OM) in patients with oral squamous cell carcinoma (OSCC) favors an elective neck dissection. However, there are barely any existing data on survival for patients with OM compared with patients with positive lymph nodes detected preoperatively. This study aims to compare survival curves of patients suffering from lymph nodal metastases in a preoperatively N+ neck with those suffering from OM. In addition, clinical characteristics of the primary tumor were analyzed to predict occult nodal disease. This retrospective cohort study includes patients with an OSCC treated surgically with R0 resection with or without adjuvant chemoradiotherapy between 2010 and 2016. Minimum follow-up was 60 months. Kaplan-Meier analysis was used to compare the survival between patients with and without occult metastases and patients with N+ neck to those with occult metastases. Logistic regression was used to detect potential risk factors for occult metastases. The patient cohort consisted of 226 patients. Occult metastases occurred in 16 of 226 patients. In 53 of 226 patients, neck lymph nodes were described as suspect on CT imaging but had a pN0 neck. Higher tumor grading increased the chance of occurrence of occult metastasis 2.7-fold (OR = 2.68, 95% CI: 1.07-6.7). After 12, 24, 48 and 60 months, 82.3%, 73.8%, 69% and 67% of the N0 patients, respectively, were progression free. In the group with OM occurrence, for the same periods 66.6%, 50%, 33.3% and 33.3% of the patients, respectively, were free of disease. For the same periods, respectively, 81%, 63%, 47% and 43% of the patients in the N+ group but without OM remained disease free. The predictors for progression-free survival were a positive N status (HR = 1.44, 95% CI: 1.08-1.93) and the occurrence of OM (HR = 2.33, 95% CI: 1.17-4.64). The presence of occult metastasis could lead to decreased survival and could be a burdening factor requiring treatment escalation and a more aggressive follow-up than nodal disease detected in the preoperative diagnostic imaging.

Postoperative Delirium in Patients with Oral Cancer: Is Intraoperative Fluid Administration a Neglected Risk Factor?

Squamous cell carcinoma (SCC) is a malignant tumor derived from squamous cells and can be found in different localizations. In the oral cavity especially, it represents the most common type of malignant tumor. First-line therapy for oral squamous cell carcinoma (OSCC) is surgery, including tumor resection, neck dissection, and maybe reconstruction. Although perioperative mortality is low, complications such as delirium are very common, and may have long-lasting consequences on the patient's quality of life. This study examines if excessive fluid administration, among other parameters, is an aggravating factor for the development of postoperative delirium. A total of 198 patients were divided into groups concerning the reconstruction technique used: group A for primary wound closure or reconstruction with a local flap, and group B for microsurgical reconstruction. The patients with and without delirium in both groups were compared regarding intraoperative fluid administration, fluid balance, and other parameters, such as blood loss, duration of surgery and overall ventilation, alcohol consumption, and creatinine, albumin, natrium, and hematocrit levels. The logistic regression for group A shows that fluid intake (p = 0.02, OR = 5.27, 95% CI 1.27-21.8) and albumin levels (p = 0.036, OR = 0.22, CI 0.054-0.908) are independent predictors for the development of delirium. For group B, gender (p = 0.026, OR = 0.34, CI 0.133-0.879) with a protective effect for females, fluid intake (p = 0.003, OR = 3.975, CI 1.606-9.839), and duration of ventilation (p = 0.025, OR = 1.178, CI 1.021-1.359) are also independent predictors for delirium. An intake of more than 3000 mL for group A, and 4150 mL for group B, increases the risk of delirium by approximately five and four times, respectively. Fluid management should be considered carefully in patients with OSCC, in order to reduce the occurrence of postoperative delirium. Different factors may become significant for the development of delirium regarding different surgical procedures.

Digital planning and individual implants for secondary reconstruction of midfacial deformities: A pilot study.

Objective: To evaluate the feasibility and accuracy of implementing three-dimensional virtual surgical planning (VSP) and subsequent transfer by additive manufactured tools in the secondary reconstruction of residual post-traumatic deformities in the midface. Methods: Patients after secondary reconstruction of post-traumatic midfacial deformities were included in this case series. The metrical deviation between the virtually planned and postoperative position of patient-specific implants (PSI) and bone segments was measured at corresponding reference points. Further information collected included demographic data, post-traumatic symptoms, and type of transfer tools. Results: Eight consecutive patients were enrolled in the study. In five patients, VSP with subsequent manufacturing of combined predrilling/osteotomy guides and PSI was performed. In three patients, osteotomy guides, repositioning guides, and individually prebent plates were used following VSP. The median distances between the virtually planned and the postoperative position of the PSI were 2.01 mm (n = 18) compared to a median distance concerning the bone segments of 3.05 mm (n = 12). In patients where PSI were used, the median displacement of the bone segments was lower (n = 7, median 2.77 mm) than in the group with prebent plates (n = 5, 3.28 mm). Conclusion: This study demonstrated the feasibility of VSP and transfer by additive manufactured tools for the secondary reconstruction of complex residual post-traumatic deformities in the midface. However, the median deviations observed in this case series were unexpectedly high. The use of navigational systems may further improve the level of accuracy.

Cancer testis antigen (PRAME) as an independent marker for survival in oral squamous cell carcinoma (OSCC).

BACKGROUND: The objective was to assess the expression patterns of the cancer testis antigen PRAME, NY-ESO1, and SSX2 in oral squamous cell carcinoma (OSSC) and to correlate the expression with clinical and histopathological parameters including progression-free survival analysis. METHODS: The study variables of this retrospective cohort study (n = 83) included demographic data, histopathological data, and information on progression-free survival. PRAME expression patterns were rated based on immunohistochemistry on tissue microarrays (TMA). The survival rate was assessed by Kaplan-Meier method and Cox regression model. The primary predictor variable was defined as the expression of PRAME and the outcome variable was progression-free survival. RESULTS: Analysis of progression-free survival using Kaplan-Meier method showed that patients with positive expression of PRAME had lower probabilities of progression-free survival (p < 0.001). According to the Cox regression model, the level of PRAME expression had a considerable and significant independent influence on progression-free survival (positive PRAME expression increasing the hazards for a negative outcome by 285% in our sample; HR = 3.85, 95% CI: 1.45-10.2, p = 0.007). The expression of SSX2 (n = 1) and NY-ESO-1 (n = 5) in our samples was rare. CONCLUSION: PRAME is expressed in OSCC and appears to be a suitable marker of progression-free survival, correlates with severe course, and may allow identification of high-risk patients with aggressive progression.

Application of the lambda plate on condylar fractures: Finite element evaluation of the fixation rigidity for different fracture patterns and plate placements.

PURPOSE: The treatment challenges of condylar fractures necessitated the production of several plate designs. Among the relatively new plate designs is the lambda plate, for which biomechanical and clinical data are lacking. The purpose of this study is to examine the rigidity of fixation achieved when the lambda plate is applied to different fractures of the condylar neck and base. METHODS: Five fractures of the condylar area were designed on a virtual model of a healthy mandible obtained from a CT scan. The fractures were reduced using the lambda plate. For the same fractures, alternative placements of the plate were simulated. The generated models were analysed using the finite element analysis for a 500 N bite load. The displacement of the two condylar fragments along the fracture line was calculated as an indicator of the rigidity of the fixation. RESULTS: The displacement along the fracture was less than 0.144 mm for the neck fractures and greater than 0.165 mm for the fractures of the condylar base. A more cranial placement of the plate for the neck fractures further reduced the displacement, while a more anterior placement of the plate for the base fractures resulted in displacements greater than 0.330 mm. CONCLUSION: According to our study, the lambda plate offers better rigidity when applied as cranially as possible for condylar neck fractures. The lambda plate did not provide adequate fixation for base fractures. A second plate at the sigmoid notch should be considered to achieve better stabilization along the fracture if the lambda plate is eventually used.

Finite element analysis of different titanium miniplates: Evaluation of three-dimensional designs applied on condylar neck fractures.

INTRODUCTION: The fixation of condylar neck fractures is raising difficulties and for this reason, many plate designs have been developed. The current study compares the performance of four miniplates used in the condylar neck. MATERIAL AND METHODS: A virtual condylar neck fracture in a mandible obtained from a CT scan was fixed with four miniplates (two straight miniplates, lambda, strut, and trapezoidal). Using finite element analysis, we examined the fragments' displacements and stress distribution in the titanium material and bone. The models were analyzed under two loading conditions: a reduced bite force of 135 N and a force of 500 N. RESULTS: No risk of material failure was observed. For a load of 135 N, all four plates offer an adequate fixation. For 500 N of applied loading, the lambda and strut plates showed the best rigidity and lowest bone strains. The two parallel plates showed the lowest rigidity and the trapezoidal plate the highest bone strains around all screws. DISCUSSION: These findings imply that three-dimensional miniplates (lambda, strut) perform better when higher loads are applied. On the other hand, the trapezoidal plate has an increased risk of screw loosening and the two straight plates higher mobility of the fragments.

Fatty Acid Receptor CD36 Functions as a Surrogate Parameter for Lymph Node Metastasis in Oral Squamous Cell Carcinoma.

PURPOSE: To investigate the expression pattern of CD36 in a patient population with oral squamous cell carcinoma (OSCC) and to correlate CD36 expression with clinical and histopathological parameters. The hypothesis was that CD36 expression correlates with the occurrence of lymph node metastasis. METHODS: To address the study objectives, a retrospective cohort study was conducted. Study variables included demographic, histopathological and survival data. CD36 expression patterns were assessed by immunohistochemistry on tissue microarrays (TMA). Logistic regression analysis, survival analysis and Cox proportional hazards model were performed. RESULTS: High CD36 expression correlated significantly with a higher T-status, grading and occurrence of lymph node metastasis. The logistic regression with binary N status as a dependent variable showed that high CD36 expression increased the chance for lymph node metastasis 45-fold (OR = 44.7, 95% CI: 10.0-316). Patients with high CD36 expression had lower probabilities of progression-free survival. CD36 had a small and non-significant independent influence on progression-free survival. CONCLUSIONS: CD36 is expressed in OSCC and correlates with tumor grading, T-status, and especially the occurrence of lymph node metastasis. CD36 may be useful for risk stratification regarding lymph node metastasis in OSCC.

Accuracy of free-hand positioned patient specific implants (PSI) in primary reconstruction after inferior and/or medial orbital wall fractures.

BACKGROUND: To assess the accuracy with which CAD/CAM-fabricated patient-specific titanium implants (PSI) are positioned for inferior and/or medial orbital wall reconstruction without the use of intraoperative navigation. METHODS: Patients who underwent a primary reconstruction of the orbital walls with PSI due to fractures were enrolled in this retrospective cohort analysis. The primary outcome variables were the mean surface distances (MSD) between virtually planned and postoperative PSI position and single linear deviations in the x-, y- and z-axis at corresponding reference points. Secondary outcome variables included demographic data, classification of orbital wall defects and clinical outcomes. RESULTS: A total of 33 PSI (orbital floor n = 22; medial wall, n = 11) were examined in 27 patients. MSD was on a comparable level for the orbital floor and medial wall (median 0.39 mm, range 0.22-1.53 mm vs. median 0.42 mm, range 0.21-0.98 mm; p = 0.56). Single linear deviations were lower for reconstructions of the orbital floor compared to the medial wall (median 0.45 vs. 0.79 mm; p < 0.05). There was no association between the occurrence of diplopia and the accuracy level (p = 0.418). CONCLUSIONS: Free-hand positioning of PSI reaches a clinically appropriate level of accuracy, limiting the necessity of navigational systems to selected cases.

Finite Element Analysis of Different Titanium Plates for Internal Fixation of Fractures of the Mandibular Condylar Neck.

PURPOSE: The purpose of the present study is to compare the performance of 4 titanium miniplates (alpha, kappa, rhomboidal, and trapezoidal) used for the fixation of condylar neck fractures by implementing computational finite element analysis. METHODS: Three-dimensional models of the plates were used to reduce a virtually created condylar neck fracture in a mandible obtained from a computed tomography scan of a healthy adult. The developed models were analyzed, making use of the finite element method under 2 loading scenarios: a reduced postoperative bite force of 135 N and a clenching force of 500 N were examined. The plating designs' performance was assessed based on displacements along the fracture area, bone strains, and plate stresses. RESULTS: For a loading limited to 135 N, all 4 plates offer an adequate fixation with a small risk of screw loosening for the rhomboidal and trapezoidal plates. For an applied force of 500 N, the alpha and kappa plates showed better results, distributing more homogeneously the strains in the bone and offering better rigidity. CONCLUSIONS: These findings implicate that the alpha and kappa plates performed better when bigger loads are applied. On the other hand, the trapezoidal and rhomboidal plates are not recommended for condylar fractures, especially if bigger functional loads are expected.

Evaluation of Complications After Open Reduction and Internal Fixation of Mandibular Condylar Base and Neck Fractures Using Trapezoidal Plates.

The purpose of the study was to evaluate the different fracture pattern of patients being treated with trapezoidal plate fixation of condylar base and neck fractures using the AOCMF Classification System to determine specific fracture pattern that are associated with failure of trapezoidal plate fixation. Ten patients with mandibular condylar base and neck fractures underwent internal fixation using trapezoidal plates. Fractures of the condylar process were classified according to the AOCMF Classification System using computed tomography data. The fracture pattern was compared to complications according to hardware failure such as plate or screw loosening and plate fracture. Plate and screw loosening of trapezoidal plates for fixation of condylar base and neck fractures was associated with fracture location in the neck region and major fragment displacement with contact loss between the proximal and distal fragment of the fracture. Further investigations such as finite-element analysis of different plating systems for fixation of condylar neck fractures are necessary to establish the optimal fixation technique for condylar neck fractures.