Navigated simultaneous lateral minimally invasive tubular and posterior mini-open access for removal and revision of triangular sacroiliac joint implants: Technical note

BACKGROUND

Sacroiliac joint (SIJ) fusion, to treat back pain caused by SIJ dysfunction, can employ open or minimally invasive surgery (MIS) techniques and either cylindrical (screw-shaped) or triangular (wedge-shaped) implants. Fusion nonunion sometimes explains recurrent SIJ pain following fusion and occasionally requires hardware revision. MIS revision minimizes patient pain, infection, and disability, but due to the triangular implant size and form factor, implant removal can present challenges for MIS access during the explantation and achieving good bony purchase for re-instrumentation. Here, we report a prone single-position lateral MIS/posterior mini-open procedure for triangular-implant SIJ fusion revision.

METHODS

The patient is a 72-year-old female who underwent right SIJ fusion for lower back and leg pain sustained after a fall two years prior but experienced recurrent pain over the subsequent two years, with imaging findings of right SIJ peri-hardware lucencies and diagnostic injections confirming persistent right-sided sacroiliitis.

RESULTS

The patient underwent hardware removal using the lateral MIS incision with table-mounted tubular access and image-guided navigation to maintain exposure, plus simultaneous re-instrumentation using a navigated S2-ilioalar screw and iliac bolt construct with connecting rod through the posterior mini-open incision made for the navigation reference frame spinous process clamp.

CONCLUSION

The use of navigation and MIS access can significantly decrease the complexity of lateral hardware removal, and mini-open navigated screw-and-rod constructs offer re-instrumentation options accessible to surgeons unfamiliar with specialized posterior SIJ systems.

On the Behavior of Honeycomb, Grid and Triangular PLA Structures under Symmetric and Asymmetric Bending

Additive manufacturing technologies enable the production of components with lightweight cores, by means of infills with various patterns and densities. Together with reduced mass and material consumption, infill geometries must ensure that strength and stiffness conditions are fulfilled. For the proper correlation of the infill type with the loading case of the part, the mechanical behavior of the infill along all three principal axes of inertia has to be known. In this paper, the behavior in symmetric and asymmetric bending of three infill geometries, commonly used in 3D printing processes (honeycomb, grid and triangles) is analyzed. The variations of deflections as a function of force orientation are presented, showing that honeycomb and triangular structures exhibit similar behaviors along the Y and Z principal axes of inertia. Furthermore, the displacements obtained for the three types of structures are compared, in relation to the consumed volume of material. The larger displacements of the grid structure compared to the honeycomb and triangular structures are highlighted.

Wannier excitons confined in hexagonal boron nitride triangular quantum dots

With the ever-growing interest in quantum computing, understanding the behavior of excitons in monolayer quantum dots has become a topic of great relevance. In this paper, we consider a Wannier exciton confined in a triangular quantum dot of hexagonal boron nitride. We begin by outlining the adequate basis functions to describe a particle in a triangular enclosure, analyzing their degeneracy and symmetries. Afterwards, we discuss the excitonic Hamiltonian inside the quantum dot and study the influence of the quantum dot dimensions on the excitonic states.

Performance Analysis of Linearly Arranged Concentric Circular Antenna Array with Low Sidelobe Level and Beamwidth Using Robust Tapering Technique

In this research, a novel antenna array named Linearly arranged Concentric Circular Antenna Array (LCCAA) is proposed, concerning lower beamwidth, lower sidelobe level, sharp ability to detect false signals, and impressive SINR performance. The performance of the proposed LCCAA beamformer is compared with geometrically identical existing beamformers using the conventional technique where the LCCAA beamformer shows the lowest beamwidth and sidelobe level (SLL) of 12.50° and -15.17 dB with equal elements accordingly. However, the performance is degraded due to look direction error, for which robust techniques, fixed diagonal loading (FDL), optimal diagonal loading (ODL), and variable diagonal loading (VDL), are applied to all the potential arrays to minimize this problem. Furthermore, the LCCAA beamformer is further simulated to reduce the sidelobe applying tapering techniques where the Hamming window shows the best performance having 17.097 dB less sidelobe level compared to the uniform window. The proposed structure is also analyzed under a robust tapered (VDL-Hamming) method which reduces around 69.92 dB and 48.39 dB more sidelobe level compared to conventional and robust techniques. Analyzing all the performances, it is clear that the proposed LCCAA beamformer is superior and provides the best performance with the proposed robust tapered (VDL-Hamming) technique.

Tuning the morphology of 2D transition metal chalcogenides via oxidizing conditions

Two-dimensional transition metal chalcogenides (TMCs) are emerging as an intriguing platform to realize nascent properties in condensed matter physics, materials science and device engineering. Controllable growing of TMCs becomes increasingly important, especially for the layer number, doping, and morphology. Here, we successfully tune the morphology of MoS₂, MoSe₂, WS₂and WSe₂, from homogenous films to individual single crystalline grains only via changing the oxidizing growth conditions. The oxidization degrees are determined by the oxygen that adsorbed on substrates and the oxygen concentrations in reaction gas together. We find the homogenous films are easily formed under the reductive conditions, triangular grains prefer the weak oxidizing conditions, and medium oxidizing conditions bring in dendritic grains with higher oxygen doping and inhomogenous photoluminescence intensities from edge to interior regions shown in the dendritic grains. These growth rules under different oxidizing conditions are easily generalized to other TMCs, which also show potential for growing specific TMCs with designed oxygen doping levels.

Triangular Vascularized Free Fibula Flap for Massive Carpal Reconstruction

Massive carpal loss following trauma, tumor, or infection poses a difficult reconstructive challenge. There are limited reconstructive options for such cases, particularly when the metacarpal bases are also lost. We describe a method of carpal reconstruction using closing wedge osteotomies in a triangular vascularized free fibular flap, and a proposed algorithm for the management of metacarpal instability in this setting.

Research and Development of a Wireless Self-Powered Sensing Device Based on Bridge Vibration Energy Collection

Traditional bridge monitoring has found it difficult to meet the current diversified needs, and frequent replacement of sensor batteries is neither economical nor environmentally friendly. This paper presents a wireless acceleration sensor with low power consumption and high sensitivity through integrated circuit design, data acquisition and wireless communication design, package design, etc. The accuracy of the sensor in data collection was verified through calibration and performance comparison tests. The ability of triangular piezoelectric cantilever beam (PCB) was tested through design and physical manufacture. Finally, the self-powered performance of the sensor was tested by connecting the sensor and the triangular PCB through a circuit, which verifies the feasibility of using the PCB to collect bridge vibration energy and convert it into electrical energy to supply power for sensor, and also explore the green energy collection and application.

Return to sport following surgical management of triangular fibrocartilage tears: a systematic review

INTRODUCTION

This review aims to provide information on return rates and times to return to sport following surgical management of triangular fibrocartilage (TFC) tears.

SOURCES OF DATA

A systematic search of CINAHAL, Cochrane, EMBASE, Google Scholar, Medline, PEDro, Scopus, SPORTDiscus and Web of Science was performed using the keywords 'triangular', 'fibro-cartilage', 'complex', 'tear', 'distal radio-ulnar joint', 'athletes', 'sports', 'non-operative', 'conservative', 'operative' and 'return to sport'.

AREAS OF AGREEMENT

In all of the 10 studies included, conservative management for 6 weeks to 6 months was the first-line treatment. If symptoms persisted following this period, surgical management was advised. Arthroscopic debridement was recommended for central tears, and arthroscopic repair was recommended for peripheral tears.

AREAS OF CONTROVERSY

The optimal treatment modalities for TFC tears remain to be defined.

GROWING POINTS

Traumatic central tears can be treated with arthroscopic debridement alone. Arthroscopic repair with an all-inside repair can improve return rates to sport over an outside-in technique for ulna-sided tears.

AREAS TIMELY FOR DEVELOPING RESEARCH

Future prospective studies should aim to establish the optimal treatment modalities for TFC tears.

Group sequential clinical trial designs for normally distributed outcome variables

In a group sequential clinical trial, accumulated data are analyzed at numerous time points to allow early decisions about a hypothesis of interest. These designs have historically been recommended for their ethical, administrative, and economic benefits. In this article, we first discuss a collection of new commands for computing the stopping boundaries and required group size of various classical group sequential designs, assuming a normally distributed outcome variable. Then, we demonstrate how the performance of several designs can be compared graphically.