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The Journal of Hand Surgery, European... Jul 2021We aimed to establish if fracture reduction will correct scapholunate angle in dorsally displaced distal radial fractures and to identify the relationship with other...
We aimed to establish if fracture reduction will correct scapholunate angle in dorsally displaced distal radial fractures and to identify the relationship with other measures of distal radial position and carpal alignment. Radiographs of 131 patients with a distal radial fracture and of 50 patients with normal radiographs were reviewed. We measured the scapholunate, radiolunate, capitolunate and metacarporadial angles on the lateral views. Linear regression modelling showed that all parameters measured were significantly associated with scapholunate angle on the first radiograph following injury. Scapholunate angle increased following distal radial fracture. Reduction of the fracture improved scapholunate angle, and this was most strongly related to change in dorsal tilt. We conclude that scaphoid flexion is likely to compensate for the dorsal tilt of the lunate as an attempt to counter its dorsal tilt, and to stabilize the wrist to maintain hand function. IV.
Topics: Humans; Lunate Bone; Range of Motion, Articular; Scaphoid Bone; Wrist Injuries; Wrist Joint
PubMed: 33444074
DOI: 10.1177/1753193420983696 -
Biomedical Engineering Online Jun 2021To provide surgical support for corrective osteotomy, we developed an image fusion system for three-dimensional (3D) preoperative planning and fluoroscopy. To assess the...
BACKGROUND
To provide surgical support for corrective osteotomy, we developed an image fusion system for three-dimensional (3D) preoperative planning and fluoroscopy. To assess the utility of this image fusion system, we evaluated the reproducibility of preoperative planning for corrective osteotomy of dorsally angulated distal radius malunion using the system and compared reproducibility without using the system.
METHODS
Ten wrists from 10 distal radius malunion patients who underwent corrective osteotomy were evaluated. 3D preoperative planning and the image fusion system were used for the image fusion group (n = 5). Only 3D preoperative planning was used for the control group (n = 5). 3D preoperative planning was performed for both groups in order to assess reduction, placement, and the choice of implants. In the image fusion group, the outline of the planned image was displayed on a monitor and overlapped with fluoroscopy images during surgery. Reproducibility was evaluated using preoperative plan and postoperative 3D images. Images were compared with the 3D coordinates of the radial styloid process (1), the volar and dorsal edges of the sigmoid notch (2) (3), and the barycentric coordinates of the three reference points. The reproducibility of the preoperative plan was evaluated by the distance of the coordinates between the plan and postoperative images for the reference points.
RESULTS
The distances between preoperative planning and postoperative reduction in the image fusion group were 2.1 ± 1.1 mm, 1.8 ± 0.7 mm, 1.9 ± 0.9 mm, and 1.4 ± 0.7 mm for reference points (1), (2), (3), and the barycenter, respectively. The distances between preoperative planning and postoperative reduction in the control group were 3.7 ± 1.0 mm, 2.8 ± 2.0 mm, 1.7 ± 0.8 mm, and 1.8 ± 1.2 mm for reference points (1), (2), (3), and the barycenter, respectively. The difference in reference point (1) was significantly smaller in the image fusion group than in the control group (P < 0.05).
CONCLUSION
Corrective osteotomy using an image fusion system will become a new surgical support method for fracture malunion. Trial registration Registered as NCT03764501 at ClinicalTrials.gov.
Topics: Fracture Fixation, Internal; Humans; Osteotomy; Radius; Radius Fractures; Reproducibility of Results
PubMed: 34193171
DOI: 10.1186/s12938-021-00901-8 -
Biology Letters Feb 2024Adaptive evolution relies on both heritable variation and selection. Variation is the raw material upon which selection acts, so any mechanism that limits or prevents...
Adaptive evolution relies on both heritable variation and selection. Variation is the raw material upon which selection acts, so any mechanism that limits or prevents the generation of heritable variation reduces the power of selection to lead to adaptation. Such limitations are termed evolutionary constraints. While it is widely accepted that constraints play an important role in shaping evolutionary outcomes, their relative importance, as opposed to adaptation, in determining evolutionary outcomes remains a subject of debate. Evolutionary constraints are often evoked as the reason behind the persistence of inaccurate mimicry. Here, we compared the variation and accuracy of body-shape mimicry in ant-mimicking spiders with that of ant-mimicking insects, predicting greater constraints, and hence inaccuracy, in spiders mimicking ants, due to their evolutionary distance from the ant model. We found high inter-species variation in mimetic accuracy, but dorsally, no overall difference in mimetic accuracy between spider and insect mimics, which is inconsistent with a constraint causing inaccurate mimicry. Our study provides empirical evidence suggesting that imperfect mimicry in spiders and insects is predominantly shaped by adaptive processes rather than constraints or chance. Our findings contribute to our understanding of the mechanisms underlying evolutionary diversity and the processes that shape phenotypic outcomes.
Topics: Animals; Predatory Behavior; Spiders
PubMed: 38351747
DOI: 10.1098/rsbl.2023.0330 -
Frontiers in Cell and Developmental... 2022Rnf220 is reported to regulate the patterning of the ventral spinal neural tube in mice. The brainstem has divergent connections with peripheral and central targets and...
Rnf220 is reported to regulate the patterning of the ventral spinal neural tube in mice. The brainstem has divergent connections with peripheral and central targets and contains unique internal neuronal groups, but the role of Rnf220 in the early development of the hindbrain has not been explored. In this study, -Cre-mediated conditional knockout ( CKO) mice were used to examine if is involved in the early morphogenesis of the hindbrain. showed restricted expression in the ventral half of ventricular zone (VZ) of the hindbrain at embryonic day (E) 10.5, and as development progressed, -expressing cells were also present in the mantle zone outside the VZ at E12.5. In CKO embryos, alterations of progenitor domains in the ventral VZ were observed at E10.5. There were significant reductions of the p1 and p2 domains shown by expression of , Olig2, and Nkx6.1, accompanied by a ventral expansion of the Dbx1 p0 domain and a dorsal expansion of the Nkx2.2 p3 domain. Different from the case in the spinal cord, the Olig2 pMN (progenitors of somatic motor neuron) domain shifted and expanded dorsally. Notably, the total range of the ventral VZ and the extent of the dorsal tube were unchanged. In addition, the post-mitotic cells derived from their corresponding progenitor domain, including oligodendrocyte precursor cells (OPCs) and serotonergic neurons (5-HTNs), were also changed in the same trend as the progenitor domains do in the CKO embryos at E12.5. In summary, our data suggest similar functions of Rnf220 in the hindbrain dorsoventral (DV) patterning as in the spinal cord with different effects on the pMN domain. Our work also reveals novel roles of Rnf220 in the development of 5-HTNs and OPCs.
PubMed: 35399523
DOI: 10.3389/fcell.2022.831365 -
The Journal of Hand Surgery Oct 2023The load axis of the carpals is located on the volar side of the normal distal radius. A volar lunate facet fracture (VLFF) is exposed to volar-shearing stress, which...
PURPOSE
The load axis of the carpals is located on the volar side of the normal distal radius. A volar lunate facet fracture (VLFF) is exposed to volar-shearing stress, which can cause volar displacement of the carpus. A previous biomechanical study reported that the load at the scaphoid fossa was located more dorsally and the pressure at the lunate fossa decreased in a dorsally-angulated model. However, the distal radius load distribution for various volar tilts remains unclear. We speculate that if the volar tilt decreases, the load distribution moves dorsally and decreases the stress on the VLFF. Therefore, we analyzed a dorsally-angulated distal radius model to evaluate changes in the load distribution using finite element analysis.
METHODS
A 3-dimensional finite element wrist model was developed using computed tomography images. The ligaments were modeled as tension-only spring elements. We considered the intact wrist model for a volar tilt of 15° and created 5 additional models for volar tilts of 10°, 5°, 0°, -5°, and -10°.
RESULTS
As the dorsal angulation increased, the stress distribution moved from volar to dorsal and from the lunate fossa toward the scaphoid fossa. The maximum stress on the volar lunate facet was reduced as volar tilt decreased. The maximum stress was higher on the lunate fossa for volar tilts from 15° to 5°. In contrast, the maximum stress was higher on the scaphoid fossa for volar tilts of ≤0°.
CONCLUSIONS
Load transmission moved from volar to dorsal and from the lunate fossa to the scaphoid fossa when the volar tilt decreased. Therefore, a decrease in the volar tilt would reduce the load on the VLFF.
CLINICAL RELEVANCE
This study provides surgeons accurate knowledge regarding load distribution of the distal radius for various volar tilts that could be helpful in treating patients with VLFFs.
Topics: Humans; Radius; Finite Element Analysis; Radius Fractures; Wrist Joint; Carpal Bones
PubMed: 35973880
DOI: 10.1016/j.jhsa.2022.02.022 -
Annals of Intensive Care Feb 2022A sequential change in body position from supine-to-both lateral positions under constant ventilatory settings could be used as a postural recruitment maneuver in case...
BACKGROUND
A sequential change in body position from supine-to-both lateral positions under constant ventilatory settings could be used as a postural recruitment maneuver in case of acute respiratory distress syndrome (ARDS), provided that sufficient positive end-expiratory pressure (PEEP) prevents derecruitment. This study aims to evaluate the feasibility and physiological effects of a sequential postural recruitment maneuver in early mechanically ventilated COVID-19 ARDS patients.
METHODS
A cohort of 15 patients receiving lung-protective mechanical ventilation in volume-controlled with PEEP based on recruitability were prospectively enrolled and evaluated in five sequentially applied positions for 30 min each: Supine-baseline; Lateral-1st side; 2nd Supine; Lateral-2nd side; Supine-final. PEEP level was selected using the recruitment-to-inflation ratio (R/I ratio) based on which patients received PEEP 12 cmHO for R/I ratio ≤ 0.5 or PEEP 15 cmHO for R/I ratio > 0.5. At the end of each period, we measured respiratory mechanics, arterial blood gases, lung ultrasound aeration, end-expiratory lung impedance (EELI), and regional distribution of ventilation and perfusion using electric impedance tomography (EIT).
RESULTS
Comparing supine baseline and final, respiratory compliance (29 ± 9 vs 32 ± 8 mL/cmHO; p < 0.01) and PaO/FIO ratio (138 ± 36 vs 164 ± 46 mmHg; p < 0.01) increased, while driving pressure (13 ± 2 vs 11 ± 2 cmHO; p < 0.01) and lung ultrasound consolidation score decreased [5 (4-5) vs 2 (1-4); p < 0.01]. EELI decreased ventrally (218 ± 205 mL; p < 0.01) and increased dorsally (192 ± 475 mL; p = 0.02), while regional compliance increased in both ventral (11.5 ± 0.7 vs 12.9 ± 0.8 mL/cmHO; p < 0.01) and dorsal regions (17.1 ± 1.8 vs 18.8 ± 1.8 mL/cmHO; p < 0.01). Dorsal distribution of perfusion increased (64.8 ± 7.3% vs 66.3 ± 7.2%; p = 0.01).
CONCLUSIONS
Without increasing airway pressure, a sequential postural recruitment maneuver improves global and regional respiratory mechanics and gas exchange along with a redistribution of EELI from ventral to dorsal lung areas and less consolidation. Trial registration ClinicalTrials.gov, NCT04475068. Registered 17 July 2020, https://clinicaltrials.gov/ct2/show/NCT04475068.
PubMed: 35150355
DOI: 10.1186/s13613-022-00988-9 -
Cureus Aug 2021Bilateral Galeazzi fracture-dislocations are extremely rare injuries and only a few case reports have been described so far in the literature. Herein, we report the case...
Bilateral Galeazzi fracture-dislocations are extremely rare injuries and only a few case reports have been described so far in the literature. Herein, we report the case of a 31-year-old bicyclist whosustained bilateral Galeazzi fracture-dislocations after a collision with a car. Both radial shaft fractures were simple (AO type 22-A2.3), at the same level (Type I: <7.5 cm from the joint line), and without severe comminution having their apex located dorsally. Internal fixation was accomplished in both fractures with an 8-hole, 3.5-mm locking plate; the stability of the distal radioulnar joint (DRUJ) was assessed with several intraoperative tests and found to be stable so that no additional stabilization was necessary. Postoperatively, the forearms were immobilized in a long forearm cast for four weeks. At the last follow-up evaluation, six years postoperatively, the patient was pain-free, had a full range of motion with a total Mayo wrist score of 95 in both wrists. Bilateral Galeazzi fracture-dislocations are rare injuries requiring proper radial fracture management and thorough assessment of DRUJ stability.
PubMed: 34603873
DOI: 10.7759/cureus.17491 -
Biophysical Journal Oct 2021Epithelial folding is a fundamental morphogenetic process that shapes planar epithelial sheets into complex three-dimensional structures. Multiple mechanisms can...
Epithelial folding is a fundamental morphogenetic process that shapes planar epithelial sheets into complex three-dimensional structures. Multiple mechanisms can generate epithelial folds, including apical constriction, which acts locally at the cellular level, differential growth on the tissue scale, or buckling because of compression from neighboring tissues. Here, we investigate the formation of dorsally located epithelial folds at segment boundaries during the late stages of Drosophila embryogenesis. We found that the fold formation at the segment boundaries occurs through the juxtaposition of two key morphogenetic processes: local apical constriction and tissue-level compressive forces from posterior segments. Further, we found that epidermal spreading and fold formation are accompanied by spatiotemporal pulses of Hedgehog (Hh) signaling. A computational model that incorporates the local forces generated from the differential tensions of the apical, basal, and lateral sides of the cell and active forces generated within the whole tissue recapitulates the overall fold formation process in wild-type and Hh overexpression conditions. In sum, this work demonstrates how epithelial folding depends on multiple, separable physical mechanisms to generate the final morphology of the dorsal epidermis. This work illustrates the modularity of morphogenetic unit operations that occur during epithelial morphogenesis.
Topics: Animals; Drosophila; Drosophila Proteins; Drosophila melanogaster; Epidermis; Hedgehog Proteins; Morphogenesis
PubMed: 34461105
DOI: 10.1016/j.bpj.2021.08.028 -
Zootaxa Sep 2021The genus Bucculentum Schweitzer Feldmann, 2009 is exceptional among the brachyuran decapods in having the augenrest dorsally inclined. Hitherto, the genus comprised two...
The genus Bucculentum Schweitzer Feldmann, 2009 is exceptional among the brachyuran decapods in having the augenrest dorsally inclined. Hitherto, the genus comprised two species, both from European Upper Jurassic localities; here, further two species are described, Bucculentum horstkuscheli, n. sp. and B. plettenbergense, n. sp., which differ in their proportions of the carapace regions and especially in their shapes of the augenrest. A newly described feature shared by all congeneric species is the groove extending from the centre of the dorsal portion of the augenrest and terminating towards the cervical groove. The function of this groove could have been to lead the water stream out from the augenrest to cleanse impurities from the muddy sea bottom, where these crabs are supposed to have lived.
Topics: Animals; Brachyura; Rivers
PubMed: 34811120
DOI: 10.11646/zootaxa.5032.3.5