Distance mapping in three-dimensional virtual surgical planning in hand, wrist and forearm surgery: a tool to avoid mistakes.

PURPOSE Three-dimensional planning in corrective surgeries in the hand and wrist has become popular throughout the last 20 years. Imaging technologies and software have improved since their first description in the late 1980s. New imaging technologies, such as distance mapping (DM), improve the safety of virtual surgical planning (VSP) and help to avoid mistakes. We describe the effective use of DM in two representative and frequently performed surgical interventions (radius malunion and scaphoid pseudoarthrosis). METHODS We simulated surgical intervention in both cases using DM. Joint spaces were quantitatively and qualitatively displayed in a colour-coded fashion, which allowed the estimation of cartilage thickness and joint space congruency. These parameters are presented in the virtual surgical planning pre- and postoperatively as well as in the actual situation in our cases. RESULTS DM had a high impact on the VSP, especially in radius corrective osteotomy, where we changed the surgical plan due to the visualization of the planned postoperative situation. The actual postoperative situation was also documented using DM, which allowed for comparison of the VSP and the achieved postoperative situation. Both patients were successfully treated, and bone healing and clinical improvement were achieved. CONCLUSION The use of colour-coded static or dynamic distance mapping is useful for virtual surgical planning of corrective osteotomies of the hand, wrist and forearm. It also allows confirmation of the correct patient treatment and assessment of the follow-up radiological documentation

Point Cloud Diffusion Models for Automatic Implant Generation

Advances in 3D printing of biocompatible materials make patient-specific implants increasingly popular. The design of these implants is, however, still a tedious and largely manual process. Existing approaches to automate implant generation are mainly based on 3D U-Net architectures on downsampled or patch-wise data, which can result in a loss of detail or contextual information. Following the recent success of Diffusion Probabilistic Models, we propose a novel approach for implant generation based on a combination of 3D point cloud diffusion models and voxelization networks. Due to the stochastic sampling process in our diffusion model, we can propose an ensemble of different implants per defect, from which the physicians can choose the most suitable one. We evaluate our method on the SkullBreak and SkullFix datasets, generating high-quality implants and achieving competitive evaluation scores

Consumer vs. High-End 3D Printers for Guided Implant Surgery—An In Vitro Accuracy Assessment Study of Different 3D Printing Technologies

This study evaluates the accuracy of drill guides fabricated in medical-grade, biocompatible materials for static, computer-aided implant surgery (sCAIS). The virtually planned drill guides of ten completed patient cases were printed (n = 40) using professional (Material Jetting (MJ)) and consumer-level three-dimensional (3D) printing technologies, namely, Stereolithography (SLA), Fused Filament Fabrication (FFF), and Digital Light Processing (DLP). After printing and post-processing, the drill guides were digitized using an optical scanner. Subsequently, the drill guide’s original (reference) data and the surface scans of the digitized 3D-printed drill guide were superimposed to evaluate their incongruencies. The accuracy of the 3D-printed drill guides was calculated by determining the root mean square (RMS) values. Additionally, cast models of the planned cases were used to check that the drill guides fitted manually. The RMS (mean ± SD) values for the accuracy of 3D-printed drill guides were—MJ (0.09 ± 0.01 mm), SLA (0.12 ± 0.02 mm), FFF (0.18 ± 0.04 mm), and DLP (0.25 ± 0.05 mm). Upon a subjective assessment, all drill guides could be mounted on the cast models without hindrance. The results revealed statistically significant differences (p < 0.01) in all except the MJ- and SLA-printed drill guides. Although the measured differences in accuracy were statistically significant, the deviations were negligible from a clinical point of view. Within the limits of this study, we conclude that consumer-level 3D printers can produce surgical guides with a similar accuracy to a high-end, professional 3D printer with reduced costs

3D-printing for orthopedic treatment of infants with cleft lips and palate deformities

Background: Since its introduction by McNeil in 1954, infant orthopedic treatment of cleft lip and palate deformities has undergone a development into various directions. Depending on the plate design, different improvements of cleft morphology and oral function can be achieved and its application might be restricted to the time before lip surgery or extend for several years. Objective(s): Today 3D printing is assuming an indispensable role in the toolbox of surgery and dentistry. We present a stepwise workflow using this technology to build infant orthopedic plates. Method(s): A silicone impression of the cleft was taken in the awake child. Based on the digitized plaster model (L1 Scanner, Imetric, Switzerland)the plate was digitally designed to a thickness of 2 mm (Meshmixer, Autodesk, US). The plate was printed (Form 2, Formlabs, US)using biocompatible Medical Class IIa resin, which is suitable for long-term intraoral use (Freeprint splint, DETAX, Germany). Post processing consisted of removal of the print support structures, polishing, and fixing a wire, which has an acrylic ovoid alar extension at its end. Finding(s): The 3D printed plate shows equivalent fitting as compared to hand-made acrylic plates; the need for manual adaptation of the plates was minimal. Mean digital planning time was 20 minutes, printing time about 90 minutes. The material costs per plate are approx. 5 CHF, with initial costs for the dental scanner of 10`000 CHF and the 3D-printer of 4`000 CHF. Conclusion(s): The described process of on-the-spot medical 3D-printing represents a simple, fast, and cost-effective new workflow for the manufacturing of infant orthopedic plates, whereas the initial investment for hardware is not negligible. The traditional way is more time-intensive (textgreater 1.5 h longer)and requires a dental technician. However, in order to achieve a completely digitalized workflow, further development of intraoral-3D-scanners is required to improve their soft tissue detection. Copyright textcopyright 201

Can Steam Sterilization Affect the Accuracy of Point-of-Care 3D Printed Polyetheretherketone (PEEK) Customized Cranial Implants? An Investigative Analysis

Polyetheretherketone (PEEK) has become the biomaterial of choice for repairing craniofacial defects over time. Prospects for the point-of-care (POC) fabrication of PEEK customized implants have surfaced thanks to the developments in three-dimensional (3D) printing systems. Consequently, it has become essential to investigate the characteristics of these in-house fabricated implants so that they meet the necessary standards and eventually provide the intended clinical benefits. This study aimed to investigate the effects of the steam sterilization method on the dimensional accuracy of POC 3D-printed PEEK customized cranial implants. The objective was to assess the influence of standard sterilization procedures on material extrusion-based 3D-printed PEEK customized implants with non-destructive material testing. Fifteen PEEK customized cranial implants were fabricated using an in-house material extrusion-based 3D printer. After fabrication, the cranial implants were digitalized with a professional-grade optical scanner before and after sterilization. The dimensional changes for the 3D-printed PEEK cranial implants were analyzed using medically certified 3D image-based engineering software. The material extrusion 3D-printed PEEK customized cranial implants displayed no statistically significant dimensional difference with steam sterilization (p > 0.05). Evaluation of the cranial implants’ accuracy revealed that the dimensions were within the clinically acceptable accuracy level with deviations under 1.00 mm. Steam sterilization does not significantly alter the dimensional accuracy of the in-house 3D-printed PEEK customized cranial implants

Strawberry gingivitis: Challenges in the diagnosis of granulomatosis with polyangiitis on gingival specimens

Strawberry gingivitis is a rare oral manifestation of granulomatosis with polyangiitis (GPA, formerly known as Wegener's granulomatosis). It manifests as a red-purple hyperplastic gingivitis that frequently goes unrecognized as a disease-specific symptom, especially if it is the primary and only manifestation of the disease. GPA is a systemic necrotizing granulomatous vasculitis that takes a fatal course without treatment. Oral health care providers, who are among the first to examine the oral cavity, should be familiar with its typical appearance, clinical course, diagnostic parameters, and management. This article highlights the challenges to early-stage diagnosis of initial multiple gingival enlargements because histologic biopsies are often nonspecific and histology alone may not be sufficient to make a correct diagnosis of GPA from gingival specimens. Because strawberry gingivitis may be the first manifestation of GPA, awareness of it should be increased so that it can be diagnosed by its unique clinical appearance and additional related diagnostic parameters even if the histologic gingival findings are nonspecific

A simple, effective, universal, and reusable osteotomy tool for jaw reconstructions with microvascular fibula transplants

Precise, expensive individual saw guides are used with increasing frequency for the reconstruction of mandibular defects with fibular grafts. In this report, an alternative is presented - the Multiuse Cutting Jig (MUC-Jig, proprietary development). It is reusable, suitable for all patients, requires simple planning based on conventional CT imaging, and is more economical.; To investigate its precision, we conducted a nonblinded experimental study, with ten participating craniomaxillofacial surgeons. Osteotomies of four different fibula segments were carried out at the same angulation, with groups defined according to the proximal and distal fixed angulation: 45°, 30°, 15°, or 0°. The sagittal cut was performed proximally, with the coronal cut performed distally. The resulting 40 segments (n = 40) were analyzed with their Tx length (primary endpoint) and osteotomy angles, and compared to the original planning.; The mean (SD) relative deviation of all grafts from the original planning was -0.08 mm (1.12) in length and -0.71° (3.15) for the angle. Only 45° (-2.04 ± 3.71°) and 30° (-1.07 ± 2.52°) cuts differed significantly (p < 0.05) from smaller angle grafts. The mean (SD) absolute deviation was 0.81 mm (0.27) in length and 2.13° (0.93) in graft angles. For individual transplants, 45° cuts (1.28 ± 1.03 mm) differed significantly (p < 0.005) from others. We observed no differences in relative length or absolute angle deviation.; The MUC-Jig is precise and cost-effective for osteotomies with medium angles and smooth reconstructions of template-guided procedures

Suplementary Material: 3D-printable Open-source Cleft Lip and Palate Impression Trays – A Single-Impression-Workflow

Open-source Impression Tray Library for Cleft Lip and Palate. Scalable set of 3D-designed cleft impression tray

Evaluation of Two 3D Printers for Guided Implant Surgery

To compare the suitability of a fused filament fabrication (FFF) consumer 3D printer with a professional digital light processing (DLP) printer for the production of surgical templates for guided oral implant surgery.; Eight virtual templates were printed with two different 3D printers. These were optically scanned and the incongruences between virtual and printed templates were determined after alignment of the surface scans and the virtual data. Minimum, maximum, and mean incongruences were determined, and a t test between both groups was performed to determine statistically significant differences in accuracy.; Templates printed with the professional DLP printer showed statistically significantly less incongruence (P = .001) than those fabricated by the consumer FFF 3D printer.; The accuracy of manufactured templates is strongly dependent on the printing device and method. At this time, the tested consumer 3D FFF printer is not suitable for the fabrication of templates for implant guided surgery. Minimum requirements regarding printers' features and 3D-printed templates need to be assessed in future studies

Insights into Orbital Symmetry: A Comprehensive Retrospective Study of 372 Computed Tomography Scans

Background: The operation planning and production of individualized implants with the help of AI-based software after orbital fractures have become increasingly important in recent years. This retrospective study aimed to investigate the healthy orbitae of 372 patients from CT images in the bone and soft tissue windows using the Disior™ Bonelogic™ CMF Orbital software. (version 2.1.28). Methods: We analyzed the variables orbital volume, length, and area as a function of age and gender and compared bone and soft tissue windows. Results: For all variables, the intraclass correlation showed excellent agreement between the bone and soft tissue windows (p 2 more area (p 2 larger orbital area (p Conclusions: These results mean that, due to the symmetry of the orbits in both the bone and soft tissue windows, the healthy orbit can be mirrored for surgical planning in the event of a fracture