Background The Latarjet coracoid process transfer procedure is an established, reliable treatment for glenoid deficiency associated with recurrent anterior shoulder instability, but changes in ...neurovascular anatomy resulting from the procedure are a concern. The purpose of our cadaveric study was to identify changes in the neurovascular anatomy after a Latarjet procedure. Materials and methods We obtained 4 paired, fresh-frozen cadaveric forequarters (8 shoulders) from the Maryland State Anatomy Board. In each shoulder, we preoperatively measured the distances from the midanterior glenoid rim to the musculocutaneous nerve, axillary nerve, and axillary artery in 2 directions (lateral to medial and superior to inferior) and with the arm in 2 positions (0° abduction/neutral rotation; 30° abduction/30° external rotation), for a total of 12 measurements. We then created a standardized bony defect in the anterior-inferior glenoid, reconstructed it with the Latarjet procedure, and repeated the same measurements. Two examiners independently took each measurement twice. Inter-rater reliability was adequate, allowing pre-Latarjet measurements to be combined, averaged, and compared with combined and averaged post-Latarjet measurements by using paired Student t tests (significance, P ≤ .05). Results We found (1) significant differences in the location of the musculocutaneous nerve in the superior-to-inferior direction for both arm positions, (2) notably lax and consistently overlapping musculocutaneous and axillary nerves, and (3) an unchanged axillary artery location. Conclusions The Latarjet procedure resulted in consistent and clinically significant alterations in the anatomic relationships of the musculocutaneous and axillary nerves, which may make them vulnerable to injury during revision surgery.
Objective: Comparative studies of social responsiveness, an ability that is impaired in autism spectrum disorders, can inform our understanding of both autism and the cognitive architecture of social ...behavior. Because there is no existing quantitative measure of social responsiveness in chimpanzees, we generated a quantitative, cross-species (human-chimpanzee) social responsiveness measure. Method: We translated the Social Responsiveness Scale (SRS), an instrument that quantifies human social responsiveness, into an analogous instrument for chimpanzees. We then retranslated this "Chimpanzee SRS" into a human "Cross-Species SRS" (XSRS). We evaluated three groups of chimpanzees (n = 29) with the Chimpanzee SRS and typical and human children with autism spectrum disorder (ASD; n = 20) with the XSRS. Results: The Chimpanzee SRS demonstrated strong interrater reliability at the three sites (ranges for individual ICCs: 0.534 to 0.866; mean ICCs: 0.851 to 0.970). As has been observed in human beings, exploratory principal components analysis of Chimpanzee SRS scores supports a single factor underlying chimpanzee social responsiveness. Human subjects' XSRS scores were fully concordant with their SRS scores (r = 0.976, p = 0.001) and distinguished appropriately between typical and ASD subjects. One chimpanzee known for inappropriate social behavior displayed a significantly higher score than all other chimpanzees at its site, demonstrating the scale's ability to detect impaired social responsiveness in chimpanzees. Conclusion: Our initial cross-species social responsiveness scale proved reliable and discriminated differences in social responsiveness across (in a relative sense) and within (in a more objectively quantifiable manner) human beings and chimpanzees. (Contains 2 figures and 3 tables.)
Controlled processing is central to episodic memory retrieval. In the present study, neural correlates of sustained, as well as transient, processing components were explored during controlled ...retrieval using a mixed blocked event-related functional magnetic resonance imaging paradigm. Results from 29 participants suggest that certain regions in prefrontal cortex, including anterior left inferior prefrontal cortex near Brodmann's Area (BA) 45/47 and more posterior and dorsal left prefrontal cortex near BA 44, increase activity on a trial-by-trial basis when high levels of control are required during retrieval. Providing direct evidence for control processes that participate on an ongoing basis, right frontal-polar cortex was strongly associated with a sustained temporal profile during high control retrieval conditions, as were several additional posterior regions, including those within left parietal cortex. These results provide evidence for functional dissociation within prefrontal cortex. Frontal-polar regions near BA 10 associate with temporally extended control processes that may underlie an attentional set, or retrieval mode, during controlled retrieval, whereas more posterior prefrontal regions associate with individual retrieval attempts. In particular, right frontal-polar cortex involvement in sustained processes reconciles a number of disparate findings that have arisen when contrasting blocked-trial paradigms with event-related paradigms.
Composition as pattern Petersen, Steve
Philosophical studies,
05/2019, Letnik:
176, Številka:
5
Journal Article
Recenzirano
I argue for patternism, a new answer to the question of when some objects compose a whole. None of the standard principles of composition comfortably capture our natural judgments, such as that my ...cat exists and my table exists, but there is nothing wholly composed of them. Patternism holds, very roughly, that some things compose a whole whenever together they form a "real pattern". Plausibly we are inclined to acknowledge the existence of my cat and my table but not of their fusion, because the first two have a kind of internal organizational coherence that their putative fusion lacks. Kolmogorov complexity theory supplies the needed rigorous sense of "internal organizational coherence".
Greater sage-grouse populations have decreased steadily since European settlement in western North America. Reduced availability of brood-rearing habitat has been identified as a limiting factor for ...many populations. We used radio-telemetry to acquire locations of sage-grouse broods from 1998 to 2012 in Strawberry Valley, Utah. Using these locations and remotely-sensed NAIP (National Agricultural Imagery Program) imagery, we 1) determined which characteristics of brood-rearing habitat could be used in widely available, high resolution imagery 2) assessed the spatial extent at which sage-grouse selected brood-rearing habitat, and 3) created a predictive habitat model to identify areas of preferred brood-rearing habitat. We used AIC model selection to evaluate support for a list of variables derived from remotely-sensed imagery. We examined the relationship of these explanatory variables at three spatial extents (45, 200, and 795 meter radii). Our top model included 10 variables (percent shrub, percent grass, percent tree, percent paved road, percent riparian, meters of sage/tree edge, meters of riparian/tree edge, distance to tree, distance to transmission lines, and distance to permanent structures). Variables from each spatial extent were represented in our top model with the majority being associated with the larger (795 meter) spatial extent. When applied to our study area, our top model predicted 75% of naïve brood locations suggesting reasonable success using this method and widely available NAIP imagery. We encourage application of our methodology to other sage-grouse populations and species of conservation concern.
To evaluate whether implant design, glenoid positioning, and other factors influenced instability and scapular notching in reverse total shoulder arthroplasty.
We retrospectively reviewed records of ...patients who had undergone reverse total shoulder arthroplasty by the senior author from July 2004 through October 2011 and who had at least 24 mo of follow-up. The 58 patients who met the criteria had 65 arthroplasties: 18 with a Grammont-type prosthesis (Grammont group) and 47 with a lateral-based prosthesis (lateral-design group). We compared the groups by rates of scapular notching and instability and by radiographic markers of glenoid position and tilt. We also compared glenoid sphere sizes and the number of subscapularis tendon repairs between the groups. Rates were compared using the Fisher exact test. Notching severity distribution was compared using the
test of association. Significance was set at
< 0.05.
The Grammont group had a higher incidence of scapular notching (13 of 18; 72%) than the lateral-design group (11 of 47; 23%) (
< 0.001) and a higher incidence of instability (3 of 18; 17%) than the lateral-design group (0 of 47; 0%) (
= 0.019). Glenoid position, glenoid sphere size, and subscapularis tendon repair were not predictive of scapular notching or instability, independent of implant design. With the lateral-based prosthesis, each degree of inferior tilt of the baseplate was associated with a 7.3% reduction in the odds of developing notching (odds ratio 0.937, 95%CI: 0.894-0.983).
The lateral-based prosthesis was associated with less instability and notching compared with the Grammont-type prosthesis. Prosthesis design appears to be more important than glenoid positioning.
Abstract
Objective
Theories of brain-network organization based on neuroimaging data have burgeoned in recent years, but the predictive power of such theories for cognition and behavior has only ...rarely been examined. Here, predictions from clinical neuropsychologists about the cognitive profiles of patients with focal brain lesions were used to evaluate a brain-network theory (Warren et al., 2014).
Method
Neuropsychologists made predictions regarding the neuropsychological profiles of a neurological patient sample (N = 30) based on lesion location. The neuropsychologists then rated the congruence of their predictions with observed neuropsychological outcomes, in regard to the “severity” of neuropsychological deficits and the “focality” of neuropsychological deficits. Based on the network theory, two types of lesion locations were identified: “target” locations (putative hubs in a brain-wide network) and “control” locations (hypothesized to play limited roles in network function).
Results
We found that patients with lesions of target locations (N = 19) had deficits of greater than expected severity that were more widespread than expected, whereas patients with lesions of control locations (N = 11) showed milder, circumscribed deficits that were more congruent with expectations.
Conclusions
The findings for the target brain locations suggest that prevailing views of brain–behavior relationships may be sharpened and refined by integrating recently proposed network-oriented perspectives.
BackgroundIt has been recognized that there is a distinction between shoulder laxity and shoulder instability and that there is a wide range of normal shoulder laxities. Our goals were (1) to ...evaluate if the ability to subluxate the shoulder over the glenoid rim in patients under anesthesia would be more prevalent than the inability to do so, (2) to determine if patients with a diagnosis of instability would have significantly more shoulder laxity in the operatively treated shoulder than in the contralateral shoulder, and (3) to evaluate the observation that higher grades of shoulder laxity would be related to a diagnosis of shoulder instability. We hypothesized that, on examination with the patient under anesthesia, most shoulders could be subluxated over the glenoid rim and that the degree of shoulder laxity would be related to diagnosis.MethodsIn the present study of 1206 patients undergoing shoulder surgery, we evaluated the symptomatic and contralateral shoulders with use of a modified anterior and posterior drawer test and a sulcus sign test, with the patients under anesthesia. The anterior and posterior translations were graded as no subluxation (Grade I), subluxation over the glenoid rim with spontaneous reduction (Grade II), or subluxation without spontaneous reduction (Grade III). The sulcus sign was graded as <1.0 cm (Grade I), 1.0 to 2.0 cm (Grade II), or >2.0 cm (Grade III).ResultsWhen the patients were evaluated while under anesthesia, the humeral head could be subluxated over the rim anteriorly in 81.6% (984 of 1206) of the patients and posteriorly in 57.5% (693 of 1206) of the patients. When the patients were evaluated while under anesthesia, there was an increase in the laxity grade anteriorly, posteriorly, and inferiorly in 50.8%, 36.3%, and 15.8% of the patients, respectively, as compared with the preoperative assessment. For all laxity testing, the higher the grade of laxity in an anterior, posterior, or inferior direction, the greater the chance that the patient had a diagnosis of instability. Compared with Grade-I laxity, Grade-III laxity increased the odds of a diagnosis of instability in the anterior (odds ratio, 170), posterior (odds ratio, 32), and inferior (odds ratio, 10.3) directions. Compared with Grade-I laxity, Grade-II laxity increased the odds of a diagnosis of instability in the anterior (odds ratio, 9.8), posterior (odds ratio, 4.6), and inferior (odds ratio, 4.4) directions.ConclusionsThe ability to subluxate the humeral head over the glenoid rim in the patient who is undergoing shoulder surgery under anesthesia is common regardless of the diagnosis. Higher grades of shoulder laxity are associated with shoulder instability.
Hypothesis Our hypothesis was that the autograft-augmented direct repair of torn triceps tendons would have strength superior than that of direct repair when compared to the strength of intact distal ...triceps tendons. Materials and methods The strength of the intact distal triceps tendon in 8 unpaired, fresh frozen cadaver specimens was measured to tendon failure by uniaxial tension in the sagittal plane. The torn triceps tendons were then repaired by direct repair (sutures through drill holes) or an autograft-augmented direct repair. Each tendon repair was biomechanically tested to failure, and load to displacement curves and the site of tendon failure were recorded. Tendon strength after each repair was compared with that of the other repair technique and with that of the intact triceps tendon. Significance was set at P < .05. Results Average failure loads for intact, direct repair, and augmented repair tendons were 1741, 317, and 593 N, respectively; augmented repairs were significantly stronger than direct repairs. In the intact tendon, failure occurred at the insertion site through a tear at the bone tendon interface or through a small cortical avulsion. In the repaired tendons, all but 1 failure occurred through the suture; 1 augmented repair failed first at the tendon and then through the suture. Discussion There is a paucity of clinical data regarding the optimal repair for distal triceps avulsion. We found that triceps repair affords less strength than the intact tendon, but augmented repair was nearly twice as strong as that of direct repair. Augmented repair may allow earlier range of motion, weightbearing, and rehabilitation, theoretically decreasing complications associated with the procedure. Conclusions Augmented triceps repair is superior to direct triceps repair for a distal triceps avulsion produced in a cadaver model.
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