Visual motion analysis has focused on decomposing image sequences into their component features. There has been little success at re-combining those features into moving objects. Here, a novel model of attentive visual motion processing is presented that addresses both decomposition of the signal into constituent features as well as the re-combination, or binding, of those features into wholes. A new feed-forward motion-processing pyramid is presented motivated by the neurobiology of primate motion processes. On this structure the Selective Tuning (ST) model for visual attention is demonstrated. There are three main contributions: (1) a new feed-forward motion processing hierarchy, the first to include a multi-level decomposition with local spatial derivatives of velocity; (2) examples of how ST operates on this hierarchy to attend to motion and to localize and label motion patterns; and (3) a new solution to the feature binding problem sufficient for grouping motion features into coherent object motion. Binding is accomplished using a top-down selection mechanism that does not depend on a single location-based saliency representation.

Low- and middle-income countries contribute to only a small percentage of publications in multiple medical fields. Editorial bias was reported to be an important reason for this. However, whether this trend exists in leading spine journals remains unclear. This study determined the composition of the editorial boards of leading spine journals and analyzed the international representation of editorial boards. The editorial board members of four leading subspecialty spine journals, including The Spine Journal , Journal of Neurosurgery: Spine , European Spine Journal , and Spine were identified from the journals’ websites. The countries of editorial board members were identified and analyzed according to the continent and country income categories classified by the World Bank. A total of 608 editorial board members were identified from the four leading spine journals. The majority (91.4%) of editorial board members were from high-income countries, followed by upper-middle income countries (7.2%), and lower-middle income countries (1.3%). No editorial board members were from low-income countries. Regarding the continent of residence, 46.5% of the editorial board members were from North America, followed by Europe (38.5%), Asia (9.9%), South America (2.8%), Oceania (1.6%), and Africa (0.7%). The editorial board members came from 40 different countries, which were concentrated in North America, Western Europe, and East Asia. The largest number of editorial board members came from the United States (42.3%), followed by Germany (6.9%), the United Kingdom (6.7%), Switzerland (5.8%), and Italy (5.1%). A lack of international representation on editorial boards exists in leading spine journals. Editorial board members from high-income countries are substantially overrepresented, while editorial board members from low- and middle-income countries are severely underrepresented. The United States is the most represented country on the editorial boards of leading spine journals.

Therapeutic study, level IV.

The objective of this study was to use finite element models to investigate the biomechanics of stable thoracolumbar burst fracture repair using unilateral short-segment fixation and 4 alternate pedicle screw systems.Four posterior pedicle screw systems were compared for unilateral short-segment fixation using finite element models: intermediate bilateral short pedicle screw fixation, intermediate bilateral long pedicle screw fixation, intermediate unilateral short pedicle screw fixation, and intermediate unilateral long pedicle screw fixation. We compared range of motion (ROM), von Mises stresses on the implants, and stress on the intervertebral discs superior and inferior to the injured vertebra during simulated spinal movements.There were no significant differences in ROM, von Mises stress, or intervertebral disc stress among the 4 intermediate pedicle screw fixation techniques for all spinal movements evaluated. In addition, there were no consolidated trends depicting beneficial differences between the short and long screw models, or between the unilateral and bilateral screw models.ROM, von Mises stress, and intervertebral disc stress are the same across the 4, posterior short-segment fixation techniques evaluated using finite element models. The simplest technique—posterior short segment fixation combined with intermediate unilateral short pedicle screw fixation—is a feasible treatment strategy for stable thoracolumbar fracture.

BackgroundMost surgeons do not fix the lesser trochanter when managing femoral intertrochanteric fractures with intramedullary nails. We have not found any published clinical studies on the relationship between the integrity of the lesser trochanter and surgical outcomes of intertrochanteric fractures treated with intramedullary nails. The purpose of this study was to evaluate the impact of the integrity of the lesser trochanter on the surgical outcome of intertrochanteric fractures.MethodsA retrospective review of 85 patients aged more than 60 years with femoral intertrochanteric fractures from January 2010 to July 2012 was performed. The patients were allocated to two groups: those with (n = 37) and without (n = 48) preoperative integrity of the lesser trochanter. Relevant patient variables and medical comorbidities were collected. Medical comorbidities were evaluated according to the American Society of Anesthesiologists classification and medical records were also reviewed for age, sex, time from injury to operation, intraoperative blood loss, volume of transfusion, operative time, length of stay, time to fracture union, Harris Hip Score 1 year postoperatively, and incidence of postoperative complications. Postoperative complications included deep infection (beneath the fascia lata), congestive heart failure, pulmonary embolus, cerebrovascular accident, pneumonia, cardiac arrhythmia, urinary tract infection, wound hematoma, pressure sores, delirium, and deep venous thrombosis. Variables were statistically compared between the two groups, with statistical significance at P<0.05.ResultsPatients with and without preoperative integrity of the lesser trochanter were comparable for all assessed clinical variables except fracture type (P < 0.05). There were no statistically significant differences between these groups in time from injury to operation, volume of transfusion, length of stay, time to fracture union, Harris Hip Score at 1 year postoperatively, and incidence of postoperative complication (P > 0.05). The group with preoperative integrity of the lesser trochanter had significantly less blood loss (107.03 ± 49.21 mL) than those without it (133.96 ± 58.08 mL) (P < 0.05) and the operative time was significantly shorter in the former (0.77 ± 0.07 hours) than the latter (0.84 ± 0.11 hours) group (P < 0.05).ConclusionsThe integrity of the lesser trochanter has no significant influence on the surgical outcome of intramedullary nail internal fixation of femoral intertrochanteric fractures.

BackgroundA three-dimensional finite element model (FEM) of the knee joint was established to analyze the biomechanical functions of the superficial and deep medial collateral ligaments (MCLs) of knee joints and to investigate the treatment of the knee medial collateral ligament injury.MethodsThe right knee joint of a healthy male volunteer was subjected to CT and MRI scans in the extended position. The scanned data were imported into MIMICS, Geomagic, and ANSYS software to establish a three-dimensional FEM of the human knee joint. The anterior-posterior translation, valgus-varus rotation, and internal-external rotation of knee joints were simulated to observe tibial displacement or valgus angle. In addition, the magnitude and distribution of valgus stress in the superficial and deep layers of the intact MCL as well as the superficial, deep, and overall deficiencies of the MCL were investigated.ResultsIn the extended position, the superficial medial collateral ligament (SMCL) would withstand maximum stresses of 48.63, 16.08, 17.23, and 16.08 MPa in resisting the valgus of knee joints, tibial forward displacement, internal rotation, and external rotation, respectively. Meanwhile, the maximum stress tolerated by the SMCL in various ranges of motion mainly focused on the femoral end point, which was located at the anterior and posterior parts of the femur in resisting valgus motion and external rotation, respectively. However, the deep medial collateral ligament could tolerate only minimum stress, which was mainly focused at the femoral start and end points.ConclusionsThis model can effectively analyze the biomechanical functions of the superficial and deep layers of the MCLs of knee joints. The results show that the knee MCL II° injury is the indication of surgical repair.

The aim of this study is to determine whether surgery offers protection against early subtalar arthrodesis in displaced intraarticular calcaneal fractures.Systematic review and meta-analysis: searches of electronic databases 1980 to August 2014, checking of reference lists, hand searching of journals, and contact with experts. Randomized controlled trials (RCTs) in which surgical treatment was compared with nonsurgical treatment of displaced intra-articular calcaneal fractures from 1980 to 2014. The modified Jadad scale was used for trial quality and effective data were pooled for meta-analysis. Study results related to early subtalar arthrodesis were extracted and risk assessment was combined with surgical treatment and nonsurgical treatment.The primary analysis included 4 studies and 966 participants. The estimated overall risk ratio was 4.40 (95% confidence interval 2.67–7.39), indicating the incidence of early subtalar arthrodesis in nonsurgical group is 4.4 times the surgical group. The results showed that surgical treatment was superior to nonsurgical treatment in protection against early subtalar arthrodesis in displaced intra-articular calcaneal fractures (Z = 5.600, P < 0.001).Surgery offers protection against early subtalar arthrodesis in displaced intra-articular calcaneal fractures.

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