Computer assisted skull base surgery: a contemporary review.

Skull base surgery has evolved significantly since Harvey Cushing's first descriptions in the early 1900s. Computer aided surgery (CAS) applications continue to expand; they include virtual surgical planning, augmented and virtual reality, 3D printing of models/cutting guides/implants, surgical navigation, and intraoperative imaging. The authors will review the current skull base CAS literature and propose a computer aided surgical workflow categorizing these applications into 3 phases: 1) Virtual planning, 2) Surgical execution, 3) Intraoperative verification.

Perception of aesthetic features after surgical treatment of craniofacial malformations by observers of the same age: An eye-tracking study.

The aim of this study is to evaluate where exactly children and adolescents of the same group look when they interact with each other, and attempt to record and analyse the data recorded by eye-tracking technology. MATERIALS AND METHODS: 60 subjects participated in the study, evenly divided into three age categories of 20 each in pre-school/primary school age (5-9 years), early adolescence (10-14 years) and late adolescence/transition to adulthood (15-19 years). Age groups were matched and categorized to be used both for creating the picture series and testing. Photographs of patients with both unilateral and bilateral cleft lip and palate were used to create the series of images which consisted of a total of 15 photos, 5 of which were photos of patients with surgically treated cleft deformity and 10 control photos with healthy faces, that were presented in random order. Using the eye-tracking module, the data on "area of first view" (area of initial attention), "area with longest view" (area of sustained attention), "time until view in this area" (time of initial attention) and "frequency of view in each area" (time of sustained attention) were calculated. RESULTS: Across all groups, there was no significant difference for the individual regions for the parameters of initial attention (area of first view), while the time until first fixation of one of the AOIs (time until view in this area) was significant for all facial regions. A predictable path of the facial scan is abandoned when secondary facial deformities are present and attention is focused more on the region of an existing deformity, which are the nose and mouth regions. CONCLUSIONS: There are significant differences in both male and female participants' viewing of faces with and without secondary cleft deformity. While in the age group of the younger test persons it was still the mouth region that received special attention from the male viewers, this shifted in the male test persons of the middle age group to the nose region, which was fixed significantly more often and faster. In the female participants, the mouth and nose regions were each looked at for twice as long compared to the healthy faces, making both the mouth and the nose region are in the focus of observation.

A survey regarding the organizational aspects and quality systems of in-house 3D printing in oral and maxillofacial surgery in Germany.

PURPOSE: The aim of the study was to get a cross-sectional overview of the current status of specific organizational procedures, quality control systems, and standard operating procedures for the use of three-dimensional (3D) printing to assist in-house workflow using additive manufacturing in oral and maxillofacial surgery (OMFS) in Germany. METHODS: An online questionnaire including dynamic components containing 16-29 questions regarding specific organizational aspects, process workflows, quality controls, documentation, and the respective backgrounds in 3D printing was sent to OMF surgeons in university and non-university hospitals as well as private practices with and without inpatient treatment facilities. Participants were recruited from a former study population regarding 3D printing; all participants owned a 3D printer and were registered with the German Association of Oral and Maxillofacial Surgery. RESULTS: Sixty-seven participants answered the questionnaires. Of those, 20 participants ran a 3D printer in-unit. Quality assurance measures were performed by 13 participants and underlying processes by 8 participants, respectively. Standard operating procedures regarding computer-aided design and manufacturing, post-processing, use, or storage of printed goods were non-existent in most printing units. Data segmentation as well as computer-aided design and manufacturing were conducted by a medical doctor in most cases (n = 19, n = 18, n = 8, respectively). Most participants (n = 8) stated that "medical device regulations did not have any influence yet, but an adaptation of the processes is planned for the future." CONCLUSION: The findings demonstrated significant differences in 3D printing management in OMFS, especially concerning process workflows, quality control, and documentation. Considering the ever-increasing regulations for medical devices, there might be a necessity for standardized 3D printing recommendations and regulations in OMFS.

Accuracy of low-cost alternative facial scanners: a prospective cohort study.

INTRODUCTION: Three-dimensional facial scans have recently begun to play an increasingly important role in the peri-therapeutic management of oral and maxillofacial and head and neck surgery cases. Face scan images can be generated by optical facial scanners utilizing line-laser, stereophotography, or structured light modalities, as well as from volumetric data: for example, from cone beam computed tomography (CBCT). This study aimed to evaluate whether two low-cost procedures for the creation of three-dimensional face scan images were capable of producing sufficiently accurate data sets for clinical analysis. MATERIALS AND METHODS: Fifty healthy volunteers were included in the study. Two test objects with defined dimensions (Lego bricks) were attached to the forehead and the left cheek of each volunteer. Facial anthropometric values (i.e., the distances between the medial canthi, the lateral canthi, the nasal alae, and the angles of the mouth) were first measured manually. Subsequently, face scans were performed with a smart device and manual photogrammetry and the values obtained were compared with the manually measured data sets. RESULTS: The anthropometric distances deviated, on average, 2.17 mm from the manual measurements (smart device scanning deviation 3.01 mm, photogrammetry deviation 1.34 mm), with seven out of eight deviations being statistically significant. For the Lego brick, from a total of 32 angles, 19 values demonstrated a significant difference from the original 90° angles. The average deviation was 6.5° (smart device scanning deviation 10.1°, photogrammetry deviation 2.8°). CONCLUSION: Manual photogrammetry demonstrated greater accuracy when creating three-dimensional face scan images; however, smart devices are more user-friendly. Dental professionals should monitor camera and smart device technical improvements carefully when choosing and adequate technique for 3D scanning.

A novel pilot animal model for bone augmentation using osseous shell technique for preclinical in vivo studies.

OBJECTIVES: Bone grafting is commonly used to reconstruct skeletal defects in the craniofacial region. Several bone augmentation models have been developed to evaluate bone formation using novel bone substitute materials. The aim of this study was to evaluate a surgical animal model for establishing a three-dimensional (3D) grafting environment in the animal's mandibular ramus for bone augmentation using the osseous shell technique, as in humans. MATERIALS AND METHODS: Osteological survey of New Zealand white (NZW) rabbit skull (Oryctolagus cuniculus): Initial osteological and imaging surveys were performed on a postmortem skull for a feasibility assessment of the surgical procedure. Postmortem pilot surgery and cone beam computed tomography imaging: a 3D osseous defect was created in the mandibular ramus through a submandibular incision. The osseous shell plates were stabilized with osteosynthesis fixation screws, and defects were filled with particular bone grafting material. In vivo surgical procedure: surgeries were conducted in four 8-week-old NZW rabbits utilizing two osseous shell materials: xenogeneic human cortical plates and autogenous rabbit cortical plates. The created 3D defects were filled using xenograft and allograft bone grafting materials. The healed defects were evaluated for bone formation after 12 weeks using histological and cone beam computed tomography imaging analysis. RESULTS: Clinical analysis 12 weeks after surgery revealed the stability of the 3D grafted bone augmentation defects using the osseous shell technique. Imaging and histological analyses confirmed the effectiveness of this model in assessing bone formation. CONCLUSIONS: The proposed animal model is a promising model with the potential to study various bone grafting materials for augmentation in the mandibular ramus using the osseous shell technique without compromising the health of the animal. The filled defects could be analyzed for osteogenesis, quantification of bone formation, and healing potential using histomorphometric analysis, in addition to 3D morphologic evaluation using radiation imaging.

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.

An update on the current training situation of German interns in oral and maxillofacial surgery at special times in 2021.

The aim of this study was to evaluate the current state of training of German interns in oral and maxillofacial surgery (OMFS) under the influence of the COVID-19 pandemic in 2021. A previously tested questionnaire consisting of 53 questions was sent to interns in German OMFS (non-) university hospitals and private practices as an online survey. The questionnaire was adapted to current topics, such as the ongoing COVID-19 pandemic, aspects concerning nighttime and weekend services, overtime hours, surgical logbooks, benefits of academic degrees and support for scientific activities, part-time employment, parental leave and childcare. Next, results of questions from before the COVID-19 pandemic were re-evaluated. The COVID-19 pandemic influenced the clinical work (71.83%) and the current state of training (68.64%) in OMFS of most participants. Nighttime and weekend services are possible for employees in possession of only one degree (87.93% with a medical degree) in most hospitals. Not having one or both doctorate degrees was considered to be a disadvantage by 54.95%. In all, 42.11% of the participants attested to a positive influence of research on their training situation, and 50% reported financial or non-financial research support from the employer. Part-time employment was possible for 78.81% of the participants. The course of training was interrupted more often for women due to parental or maternity leave (10.53% of men and 30.95% of women). A total of 40.71% of the participants reported that childcare was available at the hospital, theoretically. The state of OMFS training in Germany can be referred to as positive. Current and future challenges are diverse, including aspects originating from the ongoing COVID-19 pandemic, gender aspects, reconciliation of family and work, and flexible working hours. Addressing these topics will ensure OMFS training at the highest surgical level and further increase interns' satisfaction, preserving the specialty's popularity and reception.

Effect of orbital wall resection areas in the treatment of patients with endocrine orbitopathy.

In patients treated by orbital wall decompression for endocrine orbitopathy (EO) there is limited evidence on the effect of orbital wall resections. Thus, the aim of this study was to evaluate the effect of one, two, and three-wall resections on orbital parameters to determine if any such correlations exist. Preoperative and postoperative data from all patients at a tertiary care centre who underwent decompression surgery from 2010 - 2020 were digitally analysed. The effect of the number and area of resected walls on orbital area, orbital volume, and Hertel value, and the effect of lateral rim advancement (LARA) were determined. A total of 131 orbital areas showed an increase from a mean (SD) preoperative area of 42.0 (4.6) cm2 to 47.3 (6.1) cm2 postoperatively (p<0.001). In total, the mean (SD) area of osseous wall removed in all patients was 6.2 (1.7) cm2 at the lateral orbit (n = 129), 6.7 (2.3) cm2 at the orbital floor (n = 123), and 5.8 (1.8) cm2 at the medial orbital wall (n =30). The mean (SD) orbital volume increased by 6.0 (3.0) cm3 after decompression. There was also a significant reduction in exophthalmos of 7.3 (3.2) mm (from 25.2 (3.9) to 17.9 (3.5), p<0.001). LARA was performed in 50 patients. Changes in volume and area, and reduction in exophthalmos were not significantly different with or without LARA. The postoperative effects of orbital wall resection are predictable and exhibit a relation with six units of change. Two-wall resection is the most common intervention.

Continuous Multidisciplinary Care for Patients With Orofacial Clefts-Should the Follow-up Interval Depend on the Cleft Entity?

OBJECTIVE: The multidisciplinary follow-up of patients with cleft lip with or without palate (CL/P) is organized differently in specialized centers worldwide. The aim of this study was to evaluate the different treatment needs of patients with different manifestations of CL/P and to potentially adapt the frequency and timing of checkup examinations accordingly. DESIGN: We retrospectively analyzed the data of all patients attending the CL/P consultation hour at a tertiary care center between June 2005 and August 2020 (n = 1126). We defined 3 groups of cleft entities: (1) isolated clefts of lip or lip and alveolus (CL/A), (2) isolated clefts of the hard and/or soft palate, and (3) complete clefts of lip, alveolus and palate (CLP). Timing and type of therapy recommendations given by the specialists of different disciplines were analyzed for statistical differences. RESULTS: Patients with CLP made up the largest group (n = 537), followed by patients with cleft of the soft palate (n = 371) and CL ± A (n = 218). There were significant differences between the groups with regard to type and frequency of treatment recommendations. A therapy was recommended in a high proportion of examinations in all groups at all ages. CONCLUSION: Although there are differences between cleft entities, the treatment need of patients with orofacial clefts is generally high during the growth period. Patients with CL/A showed a similarly high treatment demand and should be monitored closely. A close follow-up for patients with diagnosis of CL/P is crucial and measures should be taken to increase participation in follow-up appointments.

3D printing in oral and maxillofacial surgery: a nationwide survey among university and non-university hospitals and private practices in Germany.

OBJECTIVES: Oral and maxillofacial surgery (OMFS) has undergone pioneering progress through the development of three-dimensional (3D) printing technologies. The aim of this study was to evaluate the use of 3D printing at OMFS university and non-university hospitals and private practices in Germany. MATERIALS AND METHODS: For explorative assessment, a dynamic online questionnaire containing 10-22 questions about the current use of 3D printing and the reasons behind it was sent to OMFS university and non-university hospitals and private practices in Germany by the study group from the German Association of Oral and Maxillofacial Surgery (DGMKG). RESULTS: In total, 156 participants responded from university (23 [14.7%]) and non-university hospitals (19 [12.2%]) and private practices without (85 [50.5%]) and with 29 (18.6%) inpatient treatment facility. Highest applications of 3D printing were in implantology (57%), microvascular bone reconstructions (25.6%), and orthognathics (21.1%). Among the participants, 37.8% reportedly were not using 3D printing. Among the hospitals and private practices, 21.1% had their own 3D printer, and 2.5% shared it with other departments. The major reason for not having a 3D printer was poor cost efficiency (37.6%). Possessing a 3D printer was motivated by independence from external providers (91.3%) and rapid template production (82.6%). The preferred printing methods were stereolithography (69.4 %) and filament printing (44.4%). CONCLUSIONS: OMFS 3D printing is established in Germany with a wide range of applications. CLINICAL RELEVANCE: The prevalence of 3D printing in hospitals and private practices is moderate. This may be enhanced by future innovations including improved cost efficiency.

Eyes wide shut: necessity and effect of adjunctive procedures after decompression surgery in patients with endocrine orbitopathy.

BACKGROUND: Orbital decompression surgery is frequently the last therapeutic measure in the surgical treatment of endocrine orbitopathy (EO). Additional rehabilitative and corrective surgical treatments are often used to improve the resulting eyelid stigmata, such as an increased lid aperture and scleral show. The aim of the study was to evaluate the effect of adjunctive surgical procedures after orbital decompression surgery in patients with EO. METHODS: A total of 120 orbitae from 65 patients with EO from 2010 to 2020 at a tertiary care center in Germany were retrospectively evaluated. Ocular surface area (OSA) and vertical palpebral fissures were three-dimensionally analyzed at the following stages: presurgical decompression, postsurgical decompression, and post-adjunctive surgical procedures. For the analysis of vertical palpebral fissures, predefined vertical line distances were measured on the upper and lower lids in the central, medial, and lateral pupillary regions. RESULTS: The initial OSA was 2,98 ± 0.85 cm2, and it decreased significantly after decompression surgery to 2.52 ± 0.62 cm2. After adjunct surgical procedures, OSA further decreased to 2,31 ± 0,55 cm2. Furthermore, a statistically significant reduction in all pupillary parameters was noted after each treatment step. More lid-lengthening procedures were performed on the lower lid than on the upper lid. Canthoplasty (n = 13) was the most frequently performed procedure during rehabilitation. CONCLUSION: Surgical decompression surgery improves OSA and leads to a significant reduction in lid aperture. Adjunctive surgical procedures, addressing the upper and lower lid, have a significant influence on the ongoing clinical course and contribute to a reduction in OSA.

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.

Osteogenic Potential of Mesenchymal Stem Cells from Adipose Tissue, Bone Marrow and Hair Follicle Outer Root Sheath in a 3D Crosslinked Gelatin-Based Hydrogel.

Bone transplantation is regarded as the preferred therapy to treat a variety of bone defects. Autologous bone tissue is often lacking at the source, and the mesenchymal stem cells (MSCs) responsible for bone repair mechanisms are extracted by invasive procedures. This study explores the potential of autologous mesenchymal stem cells derived from the hair follicle outer root sheath (MSCORS). We demonstrated that MSCORS have a remarkable capacity to differentiate in vitro towards the osteogenic lineage. Indeed, when combined with a novel gelatin-based hydrogel called Osteogel, they provided additional osteoinductive cues in vitro that may pave the way for future application in bone regeneration. MSCORS were also compared to MSCs from adipose tissue (ADMSC) and bone marrow (BMMSC) in a 3D Osteogel model. We analyzed gel plasticity, cell phenotype, cell viability, and differentiation capacity towards the osteogenic lineage by measuring alkaline phosphatase (ALP) activity, calcium deposition, and specific gene expression. The novel injectable hydrogel filled an irregularly shaped lesion in a porcine wound model displaying high plasticity. MSCORS in Osteogel showed a higher osteo-commitment in terms of calcium deposition and expression dynamics of OCN, BMP2, and PPARG when compared to ADMSC and BMMSC, whilst displaying comparable cell viability and ALP activity. In conclusion, autologous MSCORS combined with our novel gelatin-based hydrogel displayed a high capacity for differentiation towards the osteogenic lineage and are acquired by non-invasive procedures, therefore qualifying as a suitable and expandable novel approach in the field of bone regeneration therapy.

Mixed reality in oral and maxillofacial surgery: a symbiosis of virtual and augmented reality or a pointless technological gadget?

INTRODUCTION: Mixed reality (MR) represents a new evolution in technological development that combines both virtual reality (VR) and augmented reality (AR) to create a blend of the physical and digital worlds. However, the potential role of MR in preoperative diagnostics in oral and maxillofacial surgery has not been scientifically investigated and remains generally unclear. This article presents a workflow that integrated MR in its scheme. It also evaluates the potential benefit of MR compared with its predecessors, VR and AR. MATERIAL AND METHODS: MR technology was used to plan the surgical treatment of a clinical case with an extensive tumor of the left maxilla. A workflow proposal incorporating both the surgeon and radiation oncologist is presented based on this experience. A total of 10 examiners rated the usability and applicability of MR for daily routines. RESULTS: MR showed good results during preoperative planning for a surgically extensive case in terms of displaying 3D structures and enhancing the physical and virtual interactions among the examiners. Previously described drawbacks of other VR/AR applications such as nausea and motion sickness were not observed with MR. However, MR seems to lack intraoperative usability, which is a drawback. CONCLUSION: MR shows great potential in improving the preoperative assessment of 3D DICOM datasets and thus facilitating diagnostic measures. However, further improvements should be made to implement an MR workflow and incorporate it into the clinical treatment planning tree.

Clinical Follow-Up in Orofacial Clefts-Why Multidisciplinary Care Is the Key.

(1) Background: Although most clinicians involved in the treatment of cleft patients agree upon the major importance of interdisciplinary cooperation and many protocols and concepts have been discussed in the literature, there is little evidence of the relevance of continuous interdisciplinary care. We aimed to objectify the type and number of therapeutic decisions resulting from an annual multidisciplinary follow-up. (2) Methods: We retrospectively analyzed the data of all 1126 patients followed up in the weekly consultation hours for cleft patients at university clinics in Leipzig for the years 2005-2020. We assessed the clinical data of every patient and specifically evaluated the treatment decisions taken at different points in time by the participating experts of different specialties. (3) Results: In total, 3470 consultations were included in the evaluation, and in 70% of those, a therapeutic recommendation was given. Each specialty showed certain time frames with intense treatment demand, which partially overlapped. Nearly all therapy recommendations were statistically attached to a certain age (p < 0.001). (4) Conclusions: There is an exceptionally high need for the interdisciplinary assessment of patients with cleft formation. Some developmental phases are of particular importance with regard to regular follow-up and initiation of different treatment protocols. The therapy and checkup of cleft patients should be concentrated in specialized centers.

Training in oral and maxillofacial surgery in Germany - Residents' satisfaction and future challenges.

The aim of this study was to analyze the current situation of trainees in OMFS in a nationwide survey at German universities and teaching hospitals. A questionnaire about their training in OMFS and discrimination, gender (in-)equality, and reconcilability of work and family life was sent to many OMFS residents in Germany. Seventy-five questionnaires were included. The average age of the participants was 32.15 years (± 0.75 years); 47 participants were male, 22 female, and 3 "diverse". The participants' overall satisfaction rate was good. Training concepts existed in most of the teaching hospitals (54.67%). 8.11% of the participants stated discrimination existed against men while, 24.32% agreed that discrimination existed against women. Stating that discrimination against women exists, it was associated with female gender (p < 0.001), being married (p = 0.042), and not aiming for further academic degrees (p = 0.009). Overall, the training situation in Germany seems structured in most teaching hospitals. Apart from the residents' general satisfaction with the training concepts, there seems to be a matter of concern regarding discrimination especially against women and the reconcilability of work and family life in OMFS training. Furthering the establishment of structured training concepts might be useful to overcome these issues in the course of training in OMFS.

The Angiogenic Potential of Mesenchymal Stem Cells from the Hair Follicle Outer Root Sheath.

Neovascularization is regarded as a pre-requisite in successful tissue grafting of both hard and soft tissues alike. This study considers mesenchymal stem cells from hair follicle outer root sheath (MSCORS) as powerful tools with a neat angiogenic potential that could in the future have wide scopes of neo-angiogenesis and tissue engineering. Autologous MSCORS were obtained ex vivo by non-invasive plucking of hair and they were differentiated in vitro into both endothelial cells and vascular smooth muscle cells (SMCs), two crucial cellular components of vascular grafts. Assessment was carried out by immunostaining, confocal laser-scanning microscopy, gene expression analysis (qRT-PCR), quantitative analysis of anastomotic network parameters, and cumulative length quantification of immunostained α-smooth muscle actin-containing stress fibers (α -SMA). In comparison to adipose mesenchymal stem cells, MSCORS exhibited a significantly higher differentiation efficiency according to key quantitative criteria and their endothelial derivatives demonstrated a higher angiogenic potential. Furthermore, the cells were capable of depositing their own extracellular matrix in vitro in the form of a membrane-cell sheet, serving as a base for viable co-culture of endothelial cells and SMCs integrated with their autologous matrix. Differentiated MSCORS hereby provided a complex autologous cell-matrix construct that demonstrates vascularization capacity and can serve as a base for personalized repair grafting applications.

How is neck dissection performed in Oral and Maxillofacial Surgery? Results of a representative nationwide survey among university and non-university hospitals in Germany.

INTRODUCTION: Neck dissection (ND) is a surgical procedure addressing cervical lymph nodes and metastases in patients with oral squamous cell carcinoma (OSCC). The aim of this study was to analyze clinical decisions regarding indications and variations of ND in Oral and Maxillofacial Surgery (OMFS) in Germany. MATERIAL AND METHODS: A nationwide survey of the German Association of Oral and Maxillofacial Surgery was performed using dynamic online questionnaires including 38 questions. Data about oncological centers, case numbers, and staging procedures were collected. Relevant aspects, such as inclusion of level IIb and levels IV and V to ND, uni- vs. bilateral ND, and the influence of extra-nodal extension (ENE) of metastases on extension of ND were evaluated. RESULTS: Eighty-four OMFS of university and non-university hospitals participated in the study (responding rate 21.4%). Sixty-six (78.57%) stated to work at certified cancer centers and 53.57% of the hospitals treated between 50 and 100 OSCC cases per year. CT and/or MRI of the head and neck was performed in most of the staging procedures. Level IIb was included by 71 (93.42%) of the participants in selective ND. Levels IV and V were included by 53 (69.74%) in node-positive neck. In solitary ipsilateral metastases (ENE-), 49 participants (62.82%) stated to perform exclusively an ipsilateral ND and 40 (51.95%) stated to perform only an ipsilateral ND in ENE+. CONCLUSION: This study demonstrated a high rate of certified cancer centers in Germany showing differences regarding staging procedures, indications, and extension of ND, especially in increasingly complex cases. CLINICAL RELEVANCE: Clinical decisions regarding ND are dependent on case-individual aspects and must be decided individually.

Improved access in minimally invasive temporomandibular joint surgery through a novel endaural template.

BACKGROUND: Digitally designed surgical templates for minimally invasive temporomandibular joint (TMJ) surgery (MITMJS) are a promising tool for improving the safety of these procedures. Given the TMJ anatomy, the template fitting and intraoperative overview are the most important issues for a safe surgery. This article is a technical advance article that aims to describe an endaural surgical template based on the Moses approach as a possible solution in TMJ surgery. METHODS: Three patients with internal derangement were treated with the guidance of a MITMJS template based on cone beam computed tomography (CBCT) and a surface imprint of the periauricular region. None of the patients needed an additional open surgical procedure. Fitting of the templates was judged in terms of position and rotational stability. Surgical side effects and complications were recorded for each patient. RESULTS: The template design and clinical use were satisfactory for MITMJS. The templates showed satisfying fit and good visibility. In the study cohort, no bleeding, facial nerve injury, or other complications occurred after the procedure, and no visible scars were noted postoperatively. CONCLUSION: Our feasibility report on template-guided MITMJS shows a promising new application of templates. It points to improved access in arthroscopy or arthrocentesis of TMJ surgery through endaural access with an increased level of safety during surgery.