A Novel Method for Secondary Mandible Reconstruction to Re-Achieve a Native Condyle Position Comprising a New Design for Cutting Guides and New Positioning Devices.

Secondary mandibular reconstruction using fibular free flaps (FFF) is a technical challenge for surgeons. Appropriate operation planning is crucial for postoperative quality control and is notably necessary for the (re-) achievement of a physiological condylar position, and the sensible expansion and shaping of the transplant. Computer-assisted planning may help to reconstruct mandibular defects in a patient-specific and precise manner. Herein, we present a newly-developed workflow for secondary mandibular reconstruction using FFF; it comprises digital planning and in-house manufacturing to perform precise secondary mandible reconstruction. This method utilizes a newly designed positioning device to ensure the precise positioning of the fibula segments in relation to each other and the mandibular stumps. The presented in-house-printed positioning device made it possible to achieve digital planning with high precision during surgery.

Congenital Mandibular Hypoplasia: Patient-Specific Total Joint Replacement as a Line Extension in the Treatment of Complex Craniofacial Anomalies.

Introduction: Congenital mandibular hypoplasia (CMH) remains challenging because of the underlying combined hard and soft tissue deficiency. Treatment options include craniofacial distraction, orthognathic surgery, and autologous grafts, although the latter produces inadequate results after distraction and autologous grafting. Unsatisfactory long-term stability may cause relapse, necessitating reoperation. Material and Methods: We investigated the feasibility of using alloplastic total joint replacement (TJR) in growing and young adult CMH patients. The primary outcome was long-term reconstruction stability, without implant failure. Secondary outcomes were TMJ function and pain, and jaw movements achieved during surgery. Results: Three patients (age: 9-22 years) were treated by the same surgeon at one institution during 2018-2021. Anamnesis and clinical parameters were obtained from patient records. Preoperative 3D-scans were superimposed with postoperative 3D-scans and preoperative plans, including TJR-implant STL files, to measure jaw movement. All patients underwent prior reconstructive surgery. Mandibular movement of 16.4-20.1 mm in the sagittal direction was achieved. Post-TJR follow-up ranged from 24 to 42 months. No long-term complications occurred. At the latest follow-up, the maximal interincisal opening was between 21 and 40 mm, and all implants were functioning, without failure. Conclusion: In selected CMH cases, alloplastic TJR can deliver satisfactory medium-term results with predictable and stable outcomes, even in growing patients.

Consideration of specific key points improves outcome of decompression treatment in patients with endocrine orbitopathy: pre-/post-OP comparison and biomechanical simulation.

Endocrine orbitopathy is typically treated by resecting orbital walls. This procedure reduces intraorbital pressure by releasing intraorbital tissue, effectively alleviating the symptoms. However, selection of an appropriate surgical plan for treatment of endocrine orbitopathy requires careful consideration because predicting the effects of one-, two-, or three-wall resections on the release of orbital tissues is difficult. Here, based on our experience, we describe two specific orbital sites ('key points') that may significantly improve decompression results. Methodological framework of this work is mainly based on comparative analysis pre- and post-surgery tomographic images as well as image- and physics-based simulation of soft tissue outcome using the finite element modelling of mechanical soft tissue behaviour. Thereby, the optimal set of unknown modelling parameters was obtained iteratively from the minimum difference between model predictions and post-surgery ground truth data. This report presents a pre-/post-surgery study indicating a crucial role of these particular key points in improving the post-surgery outcome of decompression treatment of endocrine orbitopathy which was also supported by 3D biomechanical simulation of alternative two-wall resection plans. In particular, our experimental results show a nearly linear relationship between the resection area and amount of tissue released in the extraorbital space. However, a disproportionately higher volume of orbital outflow could be achieved under consideration of the two special key points. Our study demonstrates the importance of considering natural biomechanical obstacles to improved outcomes in two-wall resection treatment of endocrine orbitopathy. Further investigations of alternative surgery scenarios and post-surgery data are required to generalize the insights of this feasibility study.

No Significant Bone Resorption after Open Treatment of Mandibular Condylar Head Fractures in the Medium-Term.

Open treatment of condylar head fractures (CHF) is considered controversial. In this retrospective cohort study our primary objective was therefore to assess bone resorption and remodeling as well as patients function after open treatment of CHF in a medium-term follow-up (15.1 ± 2.2 months). We included 18 patients with 25 CHF who underwent open reduction and internal fixation, between 2016 and 2021, in our analysis. The clinical data and cone-beam computed tomography (CBCT) datasets were analyzed. The condylar processes were segmented in the postoperative (T1) and follow-up (T2) CBCT scans. Volumetric and linear bone changes were the primary outcome variables, measured by using a sophisticated 3D-algorithm. The mean condylar head volume decreased non-significantly from 3022.01 ± 825.77 mm3 (T1) to 2878.8 ± 735.60 mm3 (T2; p = 0.52). Morphological alterations indicated remodeling and resorption. The pre-operative maximal interincisal opening (MIO) was 19.75 ± 3.07 mm and significantly improved to 40.47 ± 1.7 mm during follow-up (p = 0.0005). Low rates of postoperative complications were observed. Open reduction of CHF leads to good clinical outcomes and low rates of medium-term complications. This study underlines the feasibility and importance of open treatment of CHF and may help to spread its acceptance as the preferred treatment option.

Gender-specific differences concerning psychosocial aspects and functional impairments that influence quality of life in oral cancer treatment.

PURPOSE: Patients with oral cancer have gender-specific differences with respect to health-related quality of life (HRQoL) and psychosocial variables (PV). The aim of the present study was to evaluate HRQoL and PV outcomes in patients treated for oral squamous cell carcinoma. METHODS: Data of 1234 patients were collected from a multicenter rehabilitation study of the German-Austrian-Swiss Cooperative Group on Tumours of the Maxillofacial Region (DÖSAK). Patient characteristics, oncological variables, post-treatment impairments, general quality of life (QoL), and PV (coping strategies, control beliefs, personal traits, perceived social support, depression, anxiety, and fear of tumor recurrence) were recorded. RESULTS: After treatment, HRQoL was similar between genders concerning general QoL, but men experienced significantly more treatment-related functional impairments influencing HRQoL. PV revealed gender-specific coping strategies, with women reporting significantly more "depressive coping," "religiosity," "fatalistic externality," and higher "social burden." Owing to their religious coping strategies, fatalistic attitude, and perceived higher social integration, women demonstrated superior disease acceptance, despite higher depression, anxiety, and lower psychosocial resilience. Conversely, men reported more introverted personal traits and lower social integration. CONCLUSION: Interventions during oral cancer treatment should address PV and have gender-specific elements to improve HRQoL after therapy.

Referencing for intraoperative navigation: Evaluation of human bias.

Navigation-assisted surgery is the gold standard for complex reconstructive procedures of the midface and facial skeleton, and artificial and anatomical landmarks are often used for reference. The correct identification of these landmarks before surgery is crucial for the accuracy of the navigation system. This study aimed to investigate the human errors in reference point placement. This retrospective study investigated 228 reference-point positions in 51 cases where navigation was utilized. The discrepancies between the actual reference point-position and manually planned preoperative reference points were quantified using Brainlab iPlanCMF 3.0.6. The referencing methods used in these cases included dental registration splints, osteosynthesis materials, anatomical landmarks, and combinations of these methods. The average discrepancy in the actual and manually planned reference points was 0.29 ± 0.41 mm. The use of anatomical landmarks demonstrated a significantly lower deviation (p < 0.05), although the differences between the errors in reference-point placement using dental registration splints, osteosynthesis materials, or combinations of these methods were not statistically significant. The frequency of misplacement of reference points was significantly higher than expected. These errors might have been caused by human bias during manual placement of the points or intraoperative difficulties caused by extensive metal artifacts. Thus, we postulate that the surgical personnel involved in planning navigation-assisted surgery should undergo intensive training. The development of new referencing methods that are less susceptible to these causes of error might help overcome human bias.

Postoperative quality of life and therapy-related impairments of oral cancer in relation to time-distance since treatment.

PURPOSE: Oral cancer resection can cause physical and psychological impairments that influence the quality of life (QoL). Depending on the postoperative time-distance, the occurrence and intensity of these impairments may change. We evaluated the sequelae and changes in therapy-related impairments during the postoperative course to detect associations between the time since surgery and the presence of disorders. METHODS: Data from a questionnaire completed by 1359 patients who underwent surgical treatment of oral squamous cell carcinoma and were involved in a multicenter rehabilitation study of the German-Austrian-Swiss Cooperative Group on Tumors of the Maxillofacial Region (DÖSAK) that included 43 oral and maxillofacial clinics in Germany, Austria, and Switzerland were retrospectively analyzed. RESULTS: Physical impairments, including those in appearance, mouth opening ability, ability to smell, gastric disorders, mandible mobility, breathing, and shoulder/arm mobility, were significantly associated with and increased with time-distance since surgery. Esthetic appearance most strongly correlated with the highest perception of worsening. Regarding psychological disorders, worry about tumor recurrence, depression, and worse prospects were significantly associated. Among the postoperative sequelae, fear of tumor recurrence decreased continuously; however, depression and worse prospects increased. The general QoL did not significantly differ overall during the postoperative course. CONCLUSIONS: Therapy-related impairments change during the postoperative course based on the time-distance since surgery. The general QoL may not markedly vary; however, single impairments, to some extent, can increase or decrease. IMPLICATIONS FOR CANCER SURVIVORS: Continuous adaptation of supportive cancer therapy is required during follow-up to sufficiently address individual treatment needs.

Endoscopically Assisted Treatment of Condylar Base and Neck Fractures: A Single Institution Analysis of Outcomes and Complications.

BACKGROUND: Conservative treatment, including observation and closed treatment, as well as open reduction and internal fixation are existing options for treating condylar process fractures. Extraoral approaches are widely preferred for open reduction and internal fixation. Transoral access for condylar base and neck fractures is not yet commonly used as it is technically demanding and requires special equipment. PURPOSE: In this study, the transoral endoscopically assisted approach is described, and its outcomes and complications were investigated. Imaging data and clinical records of 187 patients with condylar process fractures, treated via endoscopically assisted transoral approach between 2007 and 2017 were analyzed. Parameters included diagnosis and fracture classification, treatment, osteosynthesis configuration and postoperative complications. RESULTS: Early complications, including infection, transient postoperative malocclusion, pain and limited mouth opening, occurred in 35 patients (18.7%). Late onset complications, such as screw loosening were documented in only 4 patients (2.1%). Revision surgery following postoperative 3D imaging was required in only 3 cases (1.6%). Fragment length ranged from 15.5 to 38.3 mm. In 57.7% of patients with condylar fragment length < 20 mm, a single osteosynthesis plate was used, with no elevated complication rate. Two osteosynthesis plates with 4 screws each was used as standard in longer fragments. CONCLUSION: Endoscopically assisted transoral treatment of condylar process fractures is a reliable, yet technical demanding technique. It allows for reduction and fixation of fractures with a condylar fragment length of > 15 mm with low postoperative complication and revision rates.

Accuracy of Guided Surgery and Real-Time Navigation in Temporomandibular Joint Replacement Surgery.

BACKGROUND: Sophisticated guided surgery has not been implemented into total joint replacement-surgery (TJR) of the temporomandibular joint (TMJ) so far. Design and in-house manufacturing of a new advanced drilling guide with vector and length control for a typical TJR fossa component are described in this in vitro study, and its accuracy/utilization was evaluated and compared with those of intraoperative real-time navigation and already available standard drilling guides. METHODS: Skull base segmentations of five CT-datasets from different patients were used to design drilling guides with vector and length control according to virtual surgical planning (VSP) for the TJR of the TMJ. Stereolithographic models of the skull bases were printed three times for each case. Three groups were formed to compare our newly designed advanced drilling guide with a standard drilling guide and drill-tracking by real-time navigation. The deviation of screw head position, screw length and vector in the lateral skull base have been evaluated (n = 72). RESULTS: There was no difference in the screw head position between all three groups. The deviation of vector and length was significantly lower with the use of the advanced drilling guide compared with standard guide and navigation. However, no benefit in terms of accuracy on the lateral skull base by the use of real-time navigation could be observed. CONCLUSION: Since guided surgery is standard in implant dentistry and other CMF reconstructions, this new approach can be introduced into clinical practice soon, in order to increase accuracy and patient safety.

CAD/CAM-based referencing aids to reduce preoperative radiation exposure for intraoperative navigation.

BACKGROUND: All intraoperative navigation systems need a referencing procedure prior to utilization, usually requiring an additional computed tomography (CT) or cone beam computed tomograph (CBCT) scan. As new techniques in the field of Computer-aided design / Computer-aided manufacturing (CAD/CAM) have evolved, it seemed favourable to develop a new referencing method not relying on additional CT or CBCT scans. METHODS: A digital maxillary dental scan was used to create a referencing splint by CAD/CAM containing four reference points. By matching scanned dental model and initial trauma-CT, the splints position and thus the reference points were digitally simulated. These splints data were imported into the navigation system in Standard Tessellation Language (STL) format. These data were also 3D printed and the resulting piece was placed on the anatomical models' teeth. The methods accuracy was then assessed in vitro. CONCLUSION: Our method for referencing of intraoperative navigation can be feasible to avoid an additional CT or CBCT prior to navigation.

Self-centering second-generation patient-specific functionalized implants for deep orbital reconstruction.

Deep and complete reconstruction of the orbital cavity has been shown to be essential for preventing enophthalmos and hypoglobus in patients with orbital defects or deformities. Additively manufactured patient-specific titanium implants provide unlimited options in design. However, implant malpositioning can still occur, even when intraoperative imaging and navigation are used. In this study, we investigated novel orbital implants containing features facilitating self-centering. Accuracy of implant placement and reconstruction of the orbital dimensions were compared retrospectively between self-centering second-generation patient-specific functionalized orbital implants (study group) and CAD-based individualized implants (control group). Design features of implants in the study group included functionalization with navigation tracks, a preventive design, and flanges - so called stabilizers - towards opposite orbital walls. Implant position was evaluated by fusion of preoperative virtual plans and the post-therapeutic imaging. Aberrances were quantified by 3D heatmap analysis. 31 patients were assigned to the study group and 50 to the control group, respectively. In the study group, most implants were designed with either one (n = 18, 58.06%) or two (n = 10, 32.26%) stabilizers. Twice (6.45%), one stabilizer had to be shortened intraoperatively. Implant fit analysis revealed a significantly more precise (p < 0.001) positioning in the study group (n = 22/31) than in the control group (n = 42/50). Self-centering second-generation patient-specific functionalized orbital implants showed significantly more accurate implant positioning, facilitating the transformation of virtual plans into patient's anatomy. The presented design provides an additional instrument for intraoperative quality control besides intraoperative imaging and navigation.

Fulfillment of patients' information needs during oral cancer treatment and its association with posttherapeutic quality of life.

PURPOSE: Surgical therapy for oral cancer can lead to severe physical and psychological disorders that negatively impact patient quality of life (QoL). This study aimed to evaluate the relationship between fulfillment of patients' information needs during oral cancer treatment and patients' perception of posttherapeutic disorders influencing QoL. METHODS: A retrospective analysis of 1359 patients who were surgically treated for oral cancer using questionnaires administered during the multicenter rehabilitation study by the German-Austrian-Swiss Cooperative Group on Tumors of the Maxillofacial Region (DÖSAK). Patients and medical practitioners completed questionnaires following cancer treatment. RESULTS: Approximately 37% of patients felt inadequately informed about possible physical and psychological consequences of surgery. In contrast, only 16% of patients felt they were given inadequate information about the operative procedure and possible complications, and with regard to tumor diagnosis and cancer disease, only 15% of patients. Significant correlations were found between lacking information and increased perception of posttherapeutic disorders, whereas correlations with tumor-specific and operation-related parameters were markedly lower. The patients with superior QoL after treatment stated more frequently, nearly independent of individual patient characteristics, that the information that they were given prior to therapy was adequate. Information concerning possible physical and psychological consequences of an operation, however, was frequently stated to be inadequate, independent of QoL. CONCLUSION: Patients whose information needs concerning the diagnosis and treatment of oral cancer are adequately fulfilled may benefit in terms of their therapeutic outcome, experiencing less perception of posttherapeutic physical and psychological disorders and a superior QoL.

Influence of Unilateral Cleft Lip Configuration on Long-Term Facial Averageness: A New Three-Dimensional Analysis Approach.

Background: Concepts regarding cleft lip and palate care vary widely globally, as there is no international consensus. Consequently, institutional surveillance of cleft concepts is essential. In addition to subjective expert rankings, three-dimensional (3D) photogrammetry of the face has become the gold standard for evaluation and objective assessment of facial structures. We evaluated cleft configuration preoperatively to determine the influence thereof on the long-term facial appearance/averageness of unilateral cleft lip patients. Methods: Plaster models of the patient's labio-oral region and nose were made preoperatively, digitized, and cleft configuration assessed (cleft width, cleft-columella angle, nasal projection, heminasal width ratio, transverse lip length, labial height). Between 4 and 12 years after surgery, stereophotogrammetry (3D face scans) were captured to determine the patients' individual facial averageness index (FAI) as a deviation from the population mean, using proportion indices (PIs) of facial landmarks and reference data provided by Farkas and FaceBase. Results: Cleft width (r = 0.77) and columella length correlated strongly with long-term facial averageness (r = 0.52). Decreasing FAI was seen with increasing patient age (r = -0.42), indicating increasing facial averageness. Other cleft properties showed weaker correlations. Cleft alveolus did not have any impact on FAI. Conclusions: The presented method allows objective measurement of facial appearance/averageness as well as preoperative cleft properties. It might be superior to subjective assessments of facial attractiveness/appearance. Objective cleft measurements are strong predictors for future facial averageness. Increasing averageness with growth and age suggests late corrective surgery.

Accurate and cost-effective mandibular biomodels: a standardized evaluation of 3D-Printing via fused layer deposition modeling on soluble support structures.

INTRODUCTION: Medical biomodels can be used for illustration of medical conditions, preoperative planning or to facilitate pre-bending of osteosynthesis material. They have been shown to be an effective and efficient method to reduce operating time, blood loss and wound stress in cranio-maxillo-facial surgery. Lately, new time and cost-efficient 3D-printing methods have been introduced into the mass-market. The aim of this study was to establish a standardized method of evaluation and consequently evaluate Fused Layer Deposition Modeling in combination with soluble support structures for fabrication of medical biomodels regarding precision and cost-effectiveness. MATERIALS & METHODS: Twenty-one biomodels of human mandibles equipped with measuring appliances were printed on a FLDM 3D-printers (Ultimaker 3 Extended) using a polyactate filament and a water-soluble Polyvinyl alcohol-based support structures. Precision of these models was compared to commercial, polyamide sintered models and the planning data. Production costs, printing times and post processing procedures were evaluated. RESULTS: Duration of printing of mandibular biomodels was between 6 h 5 min - 15 h 9 min (mean 9 h 12 min, ±2 h 25 min). The average cost of materials was €5.90 (± €1.28) per model. With an average aberrance of 0.29 mm, FLDM printing delivered a high level of accuracy. It was significantly superior to the polyamide reference models in the area of the semilunar incision, yet inferior at the coronoid process. CONCLUSION: FLDM printers are able to provide very precise biomodels at very low costs. The use of using soluble support structures reduces time, costs and equipment needed for post processing procedures close to zero.

Three-dimensional analysis of the velopharyngeal region in patients with cleft palate and healthy individuals.

PURPOSE: This study aims to attain metric data of the velopharyngeal dimensions of healthy subjects as well as patients with velopharyngeal insufficiency using the example of cleft and lip palate (CLP) in order to determine possible differences in the volumes of both groups. METHODS: Volumes and distances of velopharyngeal areas were analyzed retrospectively using cone beam computed tomography data sets (n = 60). Group 1 included healthy patients receiving dental implants (n = 31). Group 2 was represented by patients with surgically closed cleft lip and palate (n = 29). RESULTS: Biggest differences among mean values of both groups were found for: minimum axial area (p = 0.000), airway area caudal (p = 0.000), distance between posterior nasal spine and posterior pharyngeal wall (PPW) (p = 0.014), mean distance between velum and PPW (p = 0.000), length of PPW (p = 0.000) and length of anterior pharyngeal wall (p = 0.000). CONCLUSION: Differences in the shape and geometry of the velopharyngeal area in subjects with a regular velopharyngeal structure and function and patients with cleft palate do exist. The significant differences found here can be categorized into two groups: one reflects distances between the anterior and posterior pharynx, presenting longer distances for patients with CLP. The second significant difference regards values of length in cranio-caudal direction, which is longer in healthy subjects. With regards to these values, one could conclude, that even though total volumes of both groups did not differ in size, group 1 shows three-dimensional velopharyngeal shapes that are longer and narrower, whereas shapes of patients of group 2 tend to be wider and shorter in general.