Computer-aided position planning of miniplates to treat facial bone defects

In this contribution, a software system for computer-aided position planning of miniplates to treat facial bone defects is proposed. The intra-operatively used bone plates have to be passively adapted on the underlying bone contours for adequate bone fragment stabilization. However, this procedure can lead to frequent intra-operatively performed material readjustments especially in complex surgical cases. Our approach is able to fit a selection of common implant models on the surgeon's desired position in a 3D computer model. This happens with respect to the surrounding anatomical structures, always including the possibility of adjusting both the direction and the position of the used osteosynthesis material. By using the proposed software, surgeons are able to pre-plan the out coming implant in its form and morphology with the aid of a computer-visualized model within a few minutes. Further, the resulting model can be stored in STL file format, the commonly used format for 3D printing. Using this technology, surgeons are able to print the virtual generated implant, or create an individually designed bending tool. This method leads to adapted osteosynthesis materials according to the surrounding anatomy and requires further a minimum amount of money and time.Comment: 19 pages, 13 Figures, 2 Table

Determination of strength and debonding energy of a glass-concrete interface for encapsulation-based self-healing concrete

This paper presents a combined experimental-numerical analysis to assess the strength and fracture toughness of a glass-concrete interface. This interface is present in encapsulation-based self-healing concrete. There is absence of published results of these two properties, despite their important role in the correct working of this self-healing strategy. Two setups are used: uniaxial tensile tests to assess the bonding strength and four point bending tests to get the interfacial energy. The complementary numerical models for each setup are conducted using the finite element method. Two approaches are used: cohesive zone model to study the interface strength and the virtual crack closure technique to analyze the interfacial toughness. The models are validated and used to verify the experimental interpretations. It is found that a glass-concrete interface can develop a maximum strength of approximately 1 N/mm^2 with fracture energy of 0.011 J/m^2

3D Innovations in Personalized Surgery

Current practice involves the use of 3D surgical planning and patient-specific solutions in multiple surgical areas of expertise. Patient-specific solutions have been endorsed for several years in numerous publications due to their associated benefits around accuracy, safety, and predictability of surgical outcome. The basis of 3D surgical planning is the use of high-quality medical images (e.g., CT, MRI, or PET-scans). The translation from 3D digital planning toward surgical applications was developed hand in hand with a rise in 3D printing applications of multiple biocompatible materials. These technical aspects of medical care require engineers’ or technical physicians’ expertise for optimal safe and effective implementation in daily clinical routines.The aim and scope of this Special Issue is high-tech solutions in personalized surgery, based on 3D technology and, more specifically, bone-related surgery. Full-papers or highly innovative technical notes or (systematic) reviews that relate to innovative personalized surgery are invited. This can include optimization of imaging for 3D VSP, optimization of 3D VSP workflow and its translation toward the surgical procedure, or optimization of personalized implants or devices in relation to bone surgery

A Novel Design to Canine and Feline Bone Healing Using External Fixation

Circular external fixation devices provide stabilization and improved bone healing for cats and dogs through the use of a minimally invasive procedure. This novel circular external fixation device provides an easy to use, radiolucent, safe, and economical design. The new ring design enables veterinarians to have more variability in the placement of the stabilization wires. The new clamp design has fewer parts and can be used with existing standard industry wires and pins. The use of magnets in this innovative design eliminates the complex tooling required for assembly and disassembly of the external fixation device. This design was tested to sustain a load of 584.5N, which exceeds the amount of force produced by a 50 pound canine

An Investigation of Subaxial Cervical Spine Trauma and Surgical Treatment through Biomechanical Simulation and Kinematic Analysis

In vitro biomechanical investigations can help to identify changes in subaxial cervical spine (C3-C7) stability following injury, and determine the efficacy of surgical treatments through controlled joint simulation experiments and kinematic analyses. However, with the large spectrum of cervical spine trauma, a large fraction of the potential injuries have not been examined biomechanically. This includes a lack of studies investigating prevalent flexion-distraction injuries. Therefore, the overall objective of this thesis was to investigate the changes in subaxial cervical spine kinematic stability with simulated flexion-distraction injuries and current surgical instrumentation approaches using both established and novel biomechanical techniques. Three in vitro experiments were performed with a custom-designed spinal loading simulator. The first evaluated sequential disruption of the posterior ligaments with and without a simulated facet fracture (n=7). In these specimens, posterior lateral mass screw fixation provided more stability than anterior cervical discectomy and fusion with plating (ACDFP). A second study examined a unilateral facet perch injury by reproducing a flexion-distraction injury mechanism with the simulator (n=9). The resulting soft tissue damage was quantified through meticulous dissection of each specimen, which identified the most commonly injured structures across all specimens as both facet capsules, ¾ of the annulus, and ½ of the ligamentum flavum. This information was used to develop and validate a standardized injury model (SIM) in new specimens (n=10). A final study examined the ACDFP surgical factor of graft size height (bony spacer replacing the intervertebral disc to promote fusion) for the SIM and two other injuries (n=7). Results were motion and injury dependent, which suggests that both these factors must be considered in the surgical decision. Two additional investigations were completed. The first examined mathematical techniques to generate a large number of accurate finite helical axes from six-DOF rigid body tracker output to describe changes in cervical spine kinematic stability. The second explored the effect of boundary conditions and PID control settings on the ability of the current simulator design to reproduce desired loading techniques. Ultimately, it is hoped that these results, and the protocols developed for future investigations, will provide valuable biomechanical evidence for standardized treatment algorithms

Recent trends, technical concepts and components of computer-assisted orthopedic surgery systems: A comprehensive review

Computer-assisted orthopedic surgery (CAOS) systems have become one of the most important and challenging types of system in clinical orthopedics, as they enable precise treatment of musculoskeletal diseases, employing modern clinical navigation systems and surgical tools. This paper brings a comprehensive review of recent trends and possibilities of CAOS systems. There are three types of the surgical planning systems, including: systems based on the volumetric images (computer tomography (CT), magnetic resonance imaging (MRI) or ultrasound images), further systems utilize either 2D or 3D fluoroscopic images, and the last one utilizes the kinetic information about the joints and morphological information about the target bones. This complex review is focused on three fundamental aspects of CAOS systems: their essential components, types of CAOS systems, and mechanical tools used in CAOS systems. In this review, we also outline the possibilities for using ultrasound computer-assisted orthopedic surgery (UCAOS) systems as an alternative to conventionally used CAOS systems.Web of Science1923art. no. 519

Developments in circular external fixators: a review

Circular external fixators (CEFs) are successfully used in orthopedics owing to their highly favorable stiffness characteristics which promote distraction osteogenesis. Although there are different designs of external fixators, how these features produce optimal biomechanics through structural and component designs is not well known. Therefore, the aim of this study was to conduct a review on CEFs following the PRISMA statement. A search for relevant research articles was performed on Scopus and PubMed databases providing the related keywords. Furthermore, a patent search was conducted on the Google Patent database. 126 records were found to be eligible for the review. Different designs of CEFs were summarized and tabulated based on their specific features. A bibliometric analysis was also performed on the eligible research papers. Based on the findings, the developments of CEFs in terms of materials, automation, adjustment methods, component designs, wire-clamping, and performance evaluation have been extensively discussed. The trends of the CEF design and future directions are also discussed in this review. Significant research gaps include a lack of consideration towards ease of assembly, effective wire-clamping methods, and CEFs embedded with online patient-monitoring systems, among others. An apparent lack of research interest from low-middle and low-income countries was also identified