Evaluation of the Midface by Statistical Shape Modeling.

PURPOSE: The aim of this investigation was to generate a statistical shape model (SSM) of the midface and evaluate symmetry, gender aspects, and bone thickness. METHODS: About 102 computed tomography scans were analyzed to create the SSM. This included segmentation, landmark attribution, and Procrustes and principal component analysis. Afterward, symmetry and gender differences were visualized by registration and color coding. Bone thickness was calculated by measuring the distance between outer and inner surfaces. RESULTS: Symmetry was high in all models. The male model showed a more prominent forehead, nasal bones, and larger bizygomatic width. Bone thickness resembled the concept of vertical and horizontal maxillary pillars and buttresses. CONCLUSIONS: SSM can be used to analyze midface morphology and help in virtual surgery planning. Calculation of bone thickness could also be a useful tool in surgical planning and biomechanics.

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.

Computer-Aided Versus Conventional Planning in Orbital Traumatology Using Preformed Meshes: Development of a New Workflow.

PURPOSE: Preformed orbital meshes (POMs) are routinely used in orbital traumatology. As the shapes of commercially available POMs differ, we wanted to evaluate whether investigators would use the same POM in a given situation and perform similar virtual positioning. Furthermore, we investigated whether these tasks could be performed more quickly and more reproducibly using a new software workflow. MATERIALS AND METHODS: Four investigators performed virtual planning of orbital fracture treatment in the Brainlab system (Brainlab, Munich, Germany) using 3 different POMs. Time effort, POM selection, minimum-maximum deviations, and fitting within a distance corridor were measured and compared with the new software workflow. RESULTS: Regarding time effort, a distinct learning curve was seen. An average of 15 minutes was needed, which compared inferiorly with 1 minute using the software algorithm. In POM selection, the individual choice of the investigators differed to a large extent. An identical POM was chosen in only 3 of 10 cases, and in 2 of 10 cases, all investigators and software choices were identical. Manual POM planning showed constant collision between bone and mesh with large interindividual maximum deviations. By defining collision prevention and achieving the highest concordance between bone and mesh geometry within a given distance slot, the new software was able to select and place the best-fitting POM and display regions of potential necessary presurgical modifications. CONCLUSIONS: Planning of orbital fracture treatment in a navigation system using POMs seems highly individual. Integrating new software workflows should reduce time effort and lead to reproducible planning results, which could be used in intraoperative navigation. Furthermore, our new workflow could be used for training and expanded to other anatomic regions.

Template-Based Orbital Wall Fracture Treatment Using Statistical Shape Analysis.

PURPOSE: Aim of this study was to investigate whether a mold generated from a statistical shape model of the orbit could be generated to provide a cost-efficient means for the treatment of orbital fractures. MATERIALS AND METHODS: A statistical shape model was created from 131 computed tomographic (CT) scans of unaffected adult middle European human orbits. To generate the model, CT scans were segmented in Brainlab software, preregistered using anatomic landmarks, trimmed to an identical size, and definitely registered. Then, the model was created using the global master algorithm. Based on this model, a mold consisting of a male part and a female part was constructed and printed using a rapid prototyping technique. RESULTS: A statistical shape model of the human orbit was generated from 125 CT scans. Six scans (4.5%) presented major anatomic deviations and were discarded. A solid mold based on this model was printed. Using this mold, flat titanium mesh could be successfully deformed to serve as an orbital implant. CONCLUSION: A mold based on the statistical orbital shape could serve as a cost-effective means for the treatment of orbital fractures. It allows the anatomic preformation of titanium or resorbable implant material for orbital reconstruction. Because these materials could be cut from larger sheets, the use of a mold would be a cost-effective treatment alternative.

Morphologic comparison of preformed orbital meshes.

PURPOSE: Preformed orbital titanium meshes have been introduced to improve outcomes in the treatment of orbital wall fractures. This study evaluated the geometry of different commercially available orbital meshes and compared them with an average human orbit. MATERIALS AND METHODS: Seven commercially available preformed orbital meshes were scanned using an optical scanner. For comparison, an average orbit was generated from 113 computed tomographic scans of unaffected orbits. Meshes and the average orbit were compared by registration and the calculation of congruence. RESULTS: All meshes showed a high similarity within a ±1.5-mm deviation corridor. Major differences were seen in the slope between the orbital floor and the medial wall and in the upturning toward the lateral orbital rim. CONCLUSION: Preformed orbital meshes conform highly to an average orbit, but differ in size and geometry. Using special software, the best fitting mesh could be chosen preoperatively to improve surgical outcome if its geometry were published.

Positioning of bone segments during navigated surgery.

PURPOSE: In navigated craniomaxillofacial surgery, bone segments often have to be repositioned. To keep them reliably in the desired place during referencing and osteosynthesis, a miniature external distractor can be used. MATERIALS AND METHODS: The use of a miniature external mandibular distractor is shown in a case of bilateral lateral orbital rim advancement during endocrine orbitopathy decompression surgery. RESULTS: The advantages of using a distractor are the possibility of changing the fragment position incrementally in all directions during intraoperative control with the navigated pointer and the small size of the appliance. CONCLUSIONS: Bone segments can be manipulated intraoperatively with a miniature distractor in navigated surgery.

CAD-CAM-assisted esthetic facial surgery.

PURPOSE: This report describes a fully digital workflow for computer-assisted esthetic facial surgery planning and guidance. MATERIAL AND METHODS: Using optical scans, virtual surgery is performed according to the 3-dimensional cephalometric results. Next, surgical templates are generated using rapid prototyping. These templates act as a guide during surgery. RESULTS: The workflow has been tested successfully in 4 esthetic facial surgical procedures (rhinoplasty and genioplasty). In addition to surgical assistance, the advantages of the workflow include the possibility of discussing the treatment plan interactively with the patient and comparing and measuring simulation surgery with the actual outcome. As an additional benefit, the appropriate size of the alloplastic implants can be determined preoperatively. CONCLUSIONS: Templates could improve special procedures in esthetic facial surgery.

Evaluation of Globe Position Asymmetry in Endocrine Orbitopathy Patients and a Control Group - A Computed Tomography-Based 3D Cephalometric Analysis.

Background: Previous studies have shown that patients suffering from endocrine orbitopathy (EO) seem to present with profound asymmetry in proptosis. As asymmetry might pose a major problem in planning decompression surgery, information on the amount of variation between sides and a concise evaluation method should be available. Therefore, a study based on a concise 3D cephalometric analysis was conceived to evaluate globe position. Methods: A 3D-cephalometric analysis was performed on computed tomography (CT) data from 52 orbitopathy and 54 control data sets. Using 36 anatomic landmarks, 33 distances were evaluated to measure sagittal, vertical, and horizontal globe position. Results: EO patients presented with marked exophthalmos and statistically significant asymmetry. Depending on the 2 measured distances, 38% and 42%, respectively, presented sagittal asymmetry of >2 mm, and 12% and 13%, respectively, presented with sagittal asymmetry >4mm. No such asymmetry was seen in the control group. Furthermore, EO patients showed a larger interglobe distance due to lateral globe position. Marked asymmetry correlated with male sex. Proptosis measured to the deep bony orbit correlated with values measured to the orbital aperture or with constructed Hertel values. Conclusions: Use of 3D cephalometry and CT-based analysis confirmed findings from previous clinical studies on profound sagittal asymmetry in EO. Endocrine orbitopathy leads to a sagittal-lateral globe displacement that is even more pronounced in the current study than in earlier investigations. Concerning surgical therapy, presurgical asymmetry, especially if profound, has to be considered to achieve an esthetic symmetrical outcome. Use of 3D orbital analysis is an appropriate method to describe globe position beyond clinical measurements.

Tick-Borne Encephalitis Vaccination Protects from Alimentary TBE Infection: Results from an Alimentary Outbreak.

In May 2017, a hospitalized index case of tick-borne encephalitis (TBE) was confirmed by Serology. The case was linked to alimentary infection by raw milk from a goat farm in the region of Tübingen, Baden-Württemberg, Germany, where no previous TBE cases in the area had been reported before. The TBE focus was confirmed by isolation of the TBE virus from ticks and Serological confirmation of past infection in one of the five flock goats. Additional investigations by the local public health office identified 27 consumers of goat milk at the putative period of exposure. For 20/27 exposed persons, anamnestic information was gained by the local public health office. Twelve/fourteen exposed and non-vaccinated people developed clinical illness and were confirmed as TBE cases by Serology. Five/six vaccinated and exposed people did not develop the disease. The one exposed and vaccinated person had their last TBE vaccination booster more than 15 years ago, and therefore a booster was more than 10 years overdue. None of the regularly vaccinated and exposed persons developed clinical overt TBE infection. We report the first known TBE outbreak, during which, protection by TBE vaccination against alimentary TBE infection was demonstrated.

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.

Inclusion mucous cysts of the nose: a late complication after septorhinoplasty in two cleft lip patients.

BACKGROUND: Mucous cysts of the nose are a rare complication of rhinoplasty. They may develop as a result of implantation or herniation of mucosa. The entrapped epithelium may proliferate, forming a subcutaneous cyst. PATIENTS AND METHODS: Two patients with unilateral cleft lip nose deformity had previously undergone corrective rhinoplasty. Years after the operation, they noticed a growing mass in the nasal dorsum and presented for revision rhinoplasty. Complete surgical removal was performed by an open approach, and plastic reconstruction was performed with a rib cartilaginous graft. RESULTS: In both cases, histopathological investigation revealed a mucous cyst. No recurrence of disease was observed over 2 years of monitoring. CONCLUSION: Nasal mucous cysts are not specific complications of corrective surgery for cleft lip nose. Displacement of fragments of epithelium should be avoided to prevent this unwanted sequela. For complete removal, open rhinoplasty is recommended.

Retrospective cohort study of three-wall orbital resection for treatment of endocrine orbitopathy using 3D tomographic data and biomechanical modeling.

BACKGROUND: Surgical treatment of endocrine orbitopathy can be performed by way of resecting orbital walls, which effectively releases superfluous tissue from the surgically enlarged orbital space allowing the eyeballs to move back. Existing approaches aim to select an optimal surgical strategy based on statistical correlations between the extent of the surgical procedure and the resulting bulbus displacement but do not provide an individual surgery plan or predict surgery outcome. METHODS: In this retrospective study, we performed a quantitative analysis of pre- and post-surgery 3D tomographic data of six patients and applied explorative biomechanical modeling of orbital mechanics to dissect factors influencing patient-specific outcome. FINDINGS: Our experimental results showed a large variability of the backward eyeball displacement in dependency on the amount of orbital volume flow, which could partially be described by computational simulation. Our detailed analysis revealed that patients with regular fat tissue show a good correlation between bulbus displacement and relative volume of decompressed tissue, which, in turn, correlates with decrease in hydrostatic pressure. In contrast, patients with fibrotic tissue exhibit significantly reduced and computationally less predictable eyeball translation in response to surgical tissue decompression. INTERPRETATION: Based on the results of this study we see a great potential for quantitative planning of surgical exophthalmos treatment using 3D biomechanical modeling. Conventional approaches to planning of soft tissue interventions consider, however, only the patient's 3D anatomy and widely disregard individual tissue properties. Further investigations are required to establish reliable procedures for assessment of individual tissue properties and incorporating them into patient-specific models of orbital mechanics.

Results of a prospective anthropometric and functional study about aesthetics and nasal respiration after secondary rhinoplasty in cleft lip and palate patients.

In contrast to the multitude of investigations regarding aesthetic changes in nasal surgery, few data are available concerning nasal function. This is especially important for cleft patients with a compromised nasal respiration.In this prospective study, 68 cleft patients, who underwent nasal surgery, were evaluated concerning aesthetic and respiratory outcome. To assess nasal respiration, active anterior rhinomanometry, rhinoresistometry, and acoustic rhinometry were performed preoperatively and 6 months postoperatively (without and with nasal decongestion, according to international standards). For analyzing the changes in aesthetic parameters, photographs from 3 directions, which were taken preoperatively and at least 6 months postoperatively, were compared. Thus, 57 angles and relations of lines were created out of 54 anthropometric points. The Wilcoxon test was used to compare preoperative and postoperative data (P < 0.05). Regarding aesthetic outcome, a significant improvement in many parameters was seen. The noses postoperatively proved to be significantly narrower and more symmetric and showed a better projection.Although analysis of functional respiratory data showed a significant increase in nasal volume, no change in nasal airflow and hydraulic diameter could be found.Whereas aesthetic improvement of the cleft nose is a goal, which can be achieved regularly, nasal respiration still seems to be a challenge in cleft patients. This study highlights the necessity of taking functional data to learn more about the effects of surgery. Objective methods to assess nasal respiratory function are important for planning and performing nasal surgery and are a means of quality control.

Template-based temporomandibular joint puncturing and access in minimally invasive TMJ surgery (MITMJS) - a technical note and first clinical results.

BACKGROUND: Minimally invasive temporomandibular joint surgery (MITMJS) is an option for patients suffering from severe internal derangement or adhesions. To improve TMJ access, a workflow to create surgical templates is introduced. METHODS: A workflow to generate a dividable patient specific template based on CBCT and optical scanning to access the joint is introduced. In a first clinical trial 3 patients (6 joints) were treated by way of template-guided endoscopically-assisted TMJ therapy (3 arthrocenteses and 3 arthroscopies). RESULTS: Generation and clinical use of the templates was as planned. All templates showed perfect fit and permitted instant access to the TMJ. All surgeries were performed without complications. CONCLUSIONS: Template-guidance could improve the feasibility of endoscopically-assisted TMJ therapy. An important issue is the capability to dis- and remount the template during surgery. Using in-house production, costs are affordable. TRIAL REGISTRATION: This study was registered at the Ethic Committee of the Berlin Medical Chamber ( Eth-30/17 , 12/06/2017).

Correction to: Template-based temporomandibular joint puncturing and access in minimally invasive TMJ surgery (MITMJS) - a technical note and first clinical results.

Following publication of the original article [1], the authors reported that the registration number of the ethics approval was accidentally entered under trial registration. A trial registration was not performed by the authors.

Three-dimensional changes of scleral show after surgical treatment of endocrine orbitopathy.

PURPOSE: Surgery in endocrine orbitopathy should address exophthalmos and adjunct stigmata such as increased lid aperture and scleral show. Secondary to decompression, rehabilitative surgical treatment such as blepharoplasty is routinely used to achieve this goal. Until now, however, there has been no investigation to measure the effect of decompression surgery on scleral show and lid aperture 3-dimensionally. MATERIALS AND METHODS: Ocular surface area (OSA) and lid aperture of 34 patients (67 orbits) were measured pre and post decompression surgery in a retrospective investigation using 3-dimensional (3D) stereophotogrammetry. The mean follow-up after decompression was 6 ± 4 months. RESULTS: Mean OSA ranged between 3.1 ± 1.5 cm2 (pre orbital decompression) and 2.5 ± 0.6 cm2 (post orbital decompression). Orbital decompression caused a statistically significant reduction of the surface area of about 19.4% (p < 0.001). Lid apertures showed average values between 12.7 ± 3.3 mm (pre orbital decompression) and 11.3 ± 2.2 mm (post orbital decompression). Thus orbital decompression led to a statistically significant reduction of the palpebral fissure of about 11% (p < 0.001). OSA correlated with lid aperture pre and post surgery (p < 0.001). The extent of OSA reduction showed no correlation with the amount of exophthalmos reduction. CONCLUSION: Our results show that surgical decompression, besides correcting exophthalmos, leads to a significant reduction of scleral show and lid aperture. However, it is not possible to estimate its effect on an individual basis.

Preforming of polydioxanone sheets for orbital wall fractures - A technical note.

INTRODUCTION: Polydioxanone (PDS) sheets are commonly used in the treatment of orbital wall fractures. A potential drawback of PDS is that it may be difficult to adapt to the anatomy of the orbital walls. Therefore a study was conceived to test the feasibility of preforming PDS sheets. MATERIAL AND METHODS: PDS sheet material was water-heated and preformed using a template based on a statistical anatomical model. Then the deformed sheet was cooled, stored and compared to the original model to investigate post-deformation changes. RESULTS: PDS sheet material could easily be deformed using a mould. No significant post-cooling shape changes were noticed. CONCLUSIONS: PDS sheet material can be preformed into complex geometric shapes. This could be a benefit in the treatment of orbital wall fractures.

Rare anatomical variation of the brachiocephalic trunk encountered in tracheostomy.

Tracheostomy is a common procedure in head and neck surgery and emergency medicine to secure a patent airway. Surgeons should always be aware of anatomical variants of the branches of the aortic arch, which could lead to life-threatening complications. Open tracheostomy is the safest emergency procedure.

Facial soft tissue volume decreases during metreleptin treatment in patients with partial and generalized lipodystrophy.

PURPOSE: Lipodystrophy (LD) patients suffer from loss or maldistribution of subcutaneous adipose tissue accompanied by dysregulation of several adipocyte-secreted factors, e.g., leptin. The effect of recombinant leptin (metreleptin) therapy on facial soft tissue volume in patients with non-human immunodeficiency virus LD has not been quantified to date. METHODS: Eight LD patients (six female, two male; six familial partial LD [FPLD], two generalized LD) were treated with metreleptin over 1 year. Anthropometric parameters and 3D stereophotogrammetric imaging of the patients´ faces were assessed at baseline and after 1 year of metreleptin treatment. RESULTS: Median fat mass was significantly reduced during metreleptin treatment from 22.3 kg at baseline to 20.0 kg at 1 year (p = 0.031); however, body weight, body mass index, and waist-to-hip ratio were not significantly affected. Five of the six patients with FPLD lost between 4 and 114 cm3 of facial soft tissue volume in the pre-auricular, buccal, and submandibular area during metreleptin treatment whereas a slight volume gain was seen in one FPLD patient. The two patients with generalized LD developed a volume loss of 20 and 8 cm3 in the buccal region between baseline and 1 year of metreleptin therapy, respectively. CONCLUSIONS: Metreleptin replacement leads to loss of facial soft tissue volume in FPLD and generalized LD. However, volume changes in most patients are not visible by the naked eye.