Diplopia after Isolated Inferior Orbital Wall Fracture According to the Computed Tomography Findings

Purpose: To investigate the postoperative changes in diplopia and evaluate factors that affect diplopia after isolated inferior orbital wall fracture.Methods: A retrospective study was conducted on 200 patients who underwent reconstruction surgery for isolated inferior orbital wall fracture between March 2001 and December 2020. Diplopia was categorized into peripheral, central, and full-degree types based on the history and binocular single vision. The natural course of diplopia was analyzed pre-operatively and at 1 day, 6 weeks, and 6 months postoperatively. We analyzed the orbital computed tomography images to determine fracture size (small, medium, or large), fracture site (anterior, middle, posterior, or mixed), extraocular muscle (EOM) size (swelling or deformity), EOM site (incarcerated or prolapsed), and EOM tenting.Results: Diplopia was seen in 144 out of 200 patients (72.0%) before surgery; peripheral diplopia was seen in 57 patients (39.6%), central diplopia in 46 (24.3%), and full-degree diplopia in 20 (13.9%). Pre-operative diplopia differed according to the pre-operative limitation of range of motion (LOM) (p < 0.001) and EOM site (p = 0.022). Pre-operative diplopia type differed according to the LOM direction (p = 0.018) and EOM size (p = 0.020). Diplopia persisted in 33 patients (16.5%) 6 months after the surgery. Recovery was faster in patients with peripheral diplopia compared to those with central or full-degree diplopia.Conclusions: The presence of diplopia was associated with the pre-operative LOM and EOM site but the type of diplopia was associated with LOM direction and EOM size. These factors can be used to predict the progression of diplopia in patients with isolated inferior orbital wall fracture.

Million node fracture: size matters?

Transmissivity of self-affine fractures was computed numerically as a function of the grid size. One-million-node fractures (1024 × 1024 nodes) with fractal dimensions of 2.2–2.6 were cut into successively smaller fractures (“generations”), and transmissivities computed. The number of fractures in each generation was increased by a factor of 4. Considerable scatter in transmissivity was observed for smaller grid sizes. Average transmissivity of the fractures in the generation decreased with the grid size, without approaching any asymptotic value, which indicates no representative elementary volume (REV). This happened despite the average mean aperture being the same in each generation. The results indicate that it is not possible to estimate the transmissivity of a large fracture by cutting it into smaller fractures, running flow simulations on those and averaging the results. The decrease in transmissivity with the grid size was found to be due to an increase in the flow tortuosity.

Instability and results after non-operative treatment of large anterior glenoid rim fractures: is there a correlation between fragment size or displacement and recurrence?

Introduction There is little data available on non-operative treatment of anterior glenoid rim fractures (GRF). Nothing is known about fracture size and displacement in comparison to clinical outcomes and instability in a mainly middle-aged patient population. The aim of this study was to demonstrate the results of non-operative treatment in anterior glenoid rim fractures with the special focus on potential instability/recurrence. Methods The inclusion criteria were non-operatively treated anterior GRF of at least ≥ 5 mm width using the age- and gender-matched Constant/Murley score (a.-/g.-CMS) and the Western Ontario Instability Index (WOSI). Radiographic parameters (fracture morphology, displacement, major tuberosity fractures and Hill–Sachs lesion using initial CT and radiographs) and the proportion of the fractured glenoid were detected (2D-CT-circle-method) and osteoarthritis (A.P. and axial radiographs) was classified according to Samilson/Prieto. Proportion of fractured glenoid and medial displacement were correlated with the recurrence rate and the clinical scores. Results N = 36 patients could be followed-up after a mean of 4.4 years [12–140 month, average age: 58 (± 13, 33–86) years]. The a.-/g.-CMS was 93 (± 11, 61–100) points, and the WOSI was 81% (± 22%, 35–100%) on average. The mean intraarticular displacement was 4 mm (± 3 mm; 0–14 mm). The 2D-circle-method showed a mean glenoid fracture involvement of 21% (± 11, 10–52%). Two cases of frozen shoulders and one case with biceps pathology were associated with the trauma. Within the followed-up patient group re-instability has occurred in n = 2 patients (6%) within the first two weeks after trauma. Osteoarthritis was found in n = 11 cases. There was no correlation between the scores and the fracture size/displacement [(a.-/g.-CMS vs. displacement: r = − 0.08; p = 0.6; vs. size: r = − 0.29; p = 0.2); (WOSI vs. displacement: r = − 0.14; p = 0.4; vs. size: r = − 0.37; p = 0.06)], but very large (≥ 21%) fractures with displacement ≥ 4 mm showed slightly worse results without significant difference (a.-/g.-CMS p = 0.2; WOSI p = 0.2). The apprehension test was negative in all patients at final follow-up. Conclusion Non-operative treatment of anterior GRF was associated with overall good results within a mainly middle-aged larger patient group. Re-instability is rare and is not associated with fragment size but can occur in the first weeks after trauma. Size and dislocation of the fracture is not a criterion for the prognosis of potential instability. Level of evidence Level IV, retrospective case series.

Mechanism of Support Optimization and Confined Blasting of Thick and Hard Rock with a Wedge-Structure Immediate Roof: A Case Study

Based on the occurrence conditions of a thick and hard main roof and wedge-structure immediate roof in the Zhuxianzhuang Coal Mine, the fracture characteristics and instability migration law of a thick and hard roof (THR) were examined via physical simulations. Mining zones were divided with respect to the strata behaviors and roof control difficulty levels, and the principles and methods of zonal control under THR were put forward. This study proposed a coordinated control strategy of using confined blasting in water-filled deep holes, and reasonable support optimization, which could effectively reduce the roof fracture size, increases the supporting intensity and eliminate roof-control disasters. The length of confined blasting blocks and supporting intensity were calculated using a mechanical model for roof control in the strong strata behavior zone and less-strong strata behavior zone. These key parameters were determined as 20–25 m and 1.15–1.28 MPa, respectively, and the mining strategy was successfully applied in working face 880, performing high security and reasonable economical efficiency.

The Critical Size of Ulnar Styloid Fragment for the DRUJ Stability

Background Ulnar styloid fractures can be associated with clinically significant instability of the distal radioulnar joint (DRUJ). However, the exact fragment size that results in DRUJ instability is unknown. Purpose The objective of this study was to determine the critical size of an ulnar styloid fracture that would result in a significant increase in DRUJ translation and forearm rotation. Methods Eight cadaveric specimens were used to investigate the effects of three different ulnar styloid fracture sizes on DRUJ instability: tip fracture, base fracture, and a fracture including the fovea. Forearm rotation and dorsopalmar DRUJ translation were measured after each sequential increase in fracture size. Results Relative to the uninjured state, a significant increase in forearm rotation and dorsopalmar translation was found for all three fractures. However, the fovea fracture showed a statistically significant increase in forearm rotation compared with all other fracture types and a statistically significant increase in total dorsopalmar translation compared with the tip fracture. Conclusion In this study, ulnar styloid fractures involving the fovea resulted in significantly greater DRUJ instability comparted to tip and base fractures alone. This study provides important biomechanical data regarding the critical size of ulnar styloid fractures that result in DRUJ instability and may aid in the surgical decision-making algorithm in these patients.

Computer-Aided Fracture Size Measurement in Orbital Fractures—An Alternative to Manual Evaluation

Objective: We aimed to present a novel semiautomated tool for orbital fracture size measurement and to compare the variability of the proposed method with traditional manual measurements. Methods: Maximal anteroposterior (AP) and mediolateral (ML) dimensions of orbital fractures from computed tomography images were measured for 15 patients with unilateral orbital fractures by 2 surgeons manually and with a semiautomatic software. Variability was assessed with Bland-Altman limits of agreement plots and intra-class correlation coefficients (ICCs). Results: The intra-observer ICCs in manual and automatic measurements were high, >0.9. The inter-observer ICCs in manual measurements were 0.926 (AP) and 0.631 (ML) and in automatic measurements 0.989 (AP) and 0.989 (ML). The ICCs for manual and semiautomated variability were 0.899 (AP) and 0.669 (ML). The differences were thus particularly pronounced in the ML dimensions. In addition, with the semiautomated technique, a total fracture area could be measured and compared with the total area of the bony orbit and a 3-dimensional reformatted image could be generated. Conclusions: Intra- and inter-observer variability proved to be very low for measuring fracture maximal AP length and ML width, making both the manual and the semiautomatic methods feasible clinically. The semiautomatic fracture size analysis allows better observer-independent repeatability for fracture size measurements and provides the possibility for total fracture area measurements at any orbital bony site, even in challenging nonplanar topography.

Micro-Crack Mechanism in the Fracture Evolution of Saturated Granite and Enlightenment to the Precursors of Instability

To explore the potential precursors of rock instability, it is necessary to clarify the mechanism of micro-crack from fracturing to failure, which involves the evolution of fracture size, orientation, source model, and their relationships to the loading. The waveforms of acoustic emission (AE) recorded by the sensor network attached rock sample during laboratory tests provide a data basis for solving these problems, since these observations are directly related to the characteristics of the fracturing sources. Firstly, we investigated the source mechanism, looking at the rise angle and the average frequency (RA-AF) trends during five loading stages in a uniaxial compression test. Results show that the proportion of shear events significantly increases when approaching instability. Secondly, we calculated the moment tensor for each event, considering the uncertainties of P-wave polarity, azimuth, and the takeoff angles of the rays. Moment tensor solutions suggest that there are obviously more crack events than shear events in all loading stages. Moment tensor evolutions confirmed that the decreasing of isotropic component and the increment of double-couple can be used as precursors of rock fracturing development. Considering the limitations of these two methods, it is suggested that we should be concerned more about the proportions of individual failure components and their evolutions over time, instead of absolutely classifying the events into a certain source type.

On the Density Variability of Poissonian Discrete Fracture Networks, with application to power-law fracture size distributions

This paper presents analytical solutions to estimate at any scale the fracture density variability associated to stochastic Discrete Fracture Networks. These analytical solutions are based upon the assumption that each fracture in the network is an independent event. Analytical solutions are developed for any kind of fracture density indicators. Those analytical solutions are verified by numerical computing of the fracture density variability in three-dimensional stochastic Discrete Fracture Network (DFN) models following various orientation and size distributions, including the heavy-tailed power-law fracture size distribution. We show that this variability is dependent on the fracture size distribution and the measurement scale, but not on the orientation distribution. We also show that for networks following power-law size distribution, the scaling of the three-dimensional fracture density variability clearly depends on the power-law exponent.

The “Diagonal” Lesion: A New Type of Combined Injury Pattern Involving the Impingement Fracture of Anteromedial Tibial Plateau and the Injury of Posterior Cruciate Ligament and Posterolateral Corner

The purpose of this study was to investigate the incidence and clinical characteristics of the “diagonal” lesion. A total of 273 consecutive patients with combined posterolateral corner (PLC) and posterior cruciate ligament (PCL) injuries were retrospectively analyzed. All preoperative knee joint evaluations were reviewed including the computed tomography, the anteroposterior (AP) view, the lateral view, the full-length long-standing AP view, and the physical examination results with the patient under anesthesia. Twenty-six patients (9.5%) were verified as having the “diagonal” lesions. The anteromedial impingement fractures could be categorized into small (small fracture group, n = 7) and large (large fracture group, n = 19). The PCL injuries were classified into grade 2 (n = 22) and grade 3 (n = 4). The PLC injuries could be classified into type A (n = 3), type B (n = 8), and type C (n = 15) according to the Fanelli's classification system. Notably, there were 20 chronic cases. Among them, 14 (70%) had varus deformities. The proportion of patients with varus deformity in the large fracture group was significantly higher than that of the small fracture group (p = 0.026). In this study, the incidence of the “diagonal” lesions was 9.5%. Patients who had larger fracture size tended to develop subsequent varus deformity of the lower extremity. It was important for us to recognize the PCL/PLC injuries and to fully reduce the large bony fracture during the initial treatment of the “diagonal” lesions to prevent the residual instability and varus deformity.