Anterior-posterior Location Research Articles

Knee pivot location in asymptomatic older adults

Representative data of asymptomatic, native-knee kinematics is important when studying changes in knee function across the lifespan. High-speed stereo radiography (HSSR) provides a reliable measure of knee kinematics to <1 mm of translation and 1° of rotation, but studies often have limited statistical power to make comparisons between groups or measure the contribution of individual variability. The purpose of this study is to examine in vivo condylar kinematics to quantify the transverse center-of-rotation, or pivot, location across the flexion range and challenge the medial-pivot paradigm in asymptomatic knee kinematics. We quantified the pivot location during supine leg press, knee extension, standing lunge, and gait for 53 middle-aged and older adults (27 men; 26 women: 50.8 ± 7.0 yrs, 1.75 ± 0.1 m, 79.1 ± 15.4 kg). A central- to medial-pivot location was identified for all activities with increased knee flexion associated with posterior translation of the center-of-rotation. The association between knee angle and anterior-posterior center-of-rotation location was not as strong as the relation between medial–lateral and anterior-posterior location, excluding gait. The Pearson’s correlation for gait was stronger between knee angle and anterior-posterior center-of-rotation location (P < 0.001) than medial–lateral and anterior-posterior location (P = 0.0122). Individual variability accounted for a measurable proportion in variance explained of center-of-rotation location. Unique to gait, the lateral translation of center-of-rotation location resulted in the anterior translation of center-of-rotation at <10° knee flexion. Furthermore, no association between vertical ground-reaction force and center-of-rotation was identified.

Association between myopia progression and quantity of laser treatment for retinopathy of prematurity.

Previous studies found that infants with retinopathy of prematurity (ROP) who were treated for more posterior disease with a greater number of laser spots developed higher myopia. These studies included multiple physicians with variations in laser density. In treatments by a single physician, laser spot count is a better surrogate for area of avascular retina and anterior-posterior location of disease, so that the relationship with myopia can be better assessed. Our retrospective study included infants treated with laser for ROP by a single surgeon at a single center. Exclusion criteria were irregularities during laser and additional treatment for ROP. We assessed correlation between laser spot count and change in refractive error over time using a linear mixed effects model. We studied 153 eyes from 78 subjects treated with laser for ROP. The average gestational age at birth was 25.3±1.8 weeks, birth weight 737±248 grams, laser spot count 1793±728, and post-treatment follow up 37±29 months. Between corrected ages 0-1 years, the mean spherical equivalent was +0.4±2.3 diopters; between ages 1-2, it was -1.3±3.2D; and ages 2-3 was -0.8±3.1D. Eyes that received more laser spots had significantly greater change in refractive error over time (0.30D more myopia per year per 1000 spots). None of the eyes with hyperopia before 18 months developed myopia during the follow-up period. Greater myopia developed over time in infants with ROP treated by laser to a larger area of avascular retina.

Association of ABC and RENAL Scoring Systems With Morbidity in Partial Nephrectomy.

Different nephrometry scoring systems (NSSs) are used to evaluate the surgical complexity and outcomes of partial nephrectomy (PN) in patients with small renal tumors. This study aimed to assess the validity of nephrometry scoring systems towards aiding the preoperative planning of laparoscopic partial nephrectomy (PN). Data of 77 patients who underwent partial nephrectomy at the Puerto Real University Hospital between January 2011 and December 2017 were retrospectively analyzed. Statistical analyses were carried out to determine whether there was an association between the complexity of the surgical procedure and the assigned nephrometry scores. Operative complications (bleeding volume, conversion to open surgery, perioperative bleeding, and postoperative fistula) were significantly associated with independent variables (age, sex, body mass index, radiological tumor size, and operative ischemia time) and with the classification of patients using arterial-based complexity (ABC) and radius endophytic/exophytic nearness anterior-posterior location (RENAL) scores. There was also a strong correlation between the RENAL and ABC scores [Cramer's V coefficient (0.682) and Fisher's test (p<0.0001)]. The RENAL and ABC scores are associated with the risk of the complexity of partial nephrectomy for T1 renal tumors, even for ≥T1b tumors and/or with complex anatomical features.

Sling Exercise Can Drive Cortical Representation of the Transversus Abdominis and Multifidus Muscles in Patients With Chronic Low Back Pain.

ObjectiveThe transversus abdominis (TrA) and multifidus (MF) muscles are essential in preventing chronic low back pain (CLBP) recurrence by maintaining segmental stabilization and stiffness. Sling exercise is a high-level core stability training to effectively improve the activities of the TrA and MF muscles. However, the neural mechanism for sling exercise-induced neural plasticity change in the primary motor cortex (M1) remains unclear. This study aimed to investigate the role of sling exercise in the reorganization of the motor cortical representation of the TrA and MF muscles.MethodsTwenty patients with CLBP and 10 healthy individuals were recruited. For map volume, area, the center of gravity (CoG) location (medial-lateral location and anterior-posterior location), and latency, two-way ANOVA was performed to compare the effects of groups (the CLBP-pre, CLBP-post, and healthy groups) and the two muscles (the TrA and MF muscles). The Visual Analog Scale (VAS), the Oswestry Disability Index (ODI), and postural balance stability were assessed at baseline and at the end of 2 weeks of sling exercise. Linear correlations between VAS or ODI and CoG locations were assessed by Pearson's correlation test.Results2 weeks of sling exercise induced both the anterior-medial (P < 0.001) and anterior-posterior (P = 0.025) shifts of the MF muscle representation at the left motor cortex in patients with CLBP. Anterior-medial (P = 0.009) shift of the TrA muscle representation at the right motor cortex was observed in patients with CLBP. The motor cortical representation of the two muscles in patients with CLBP after sling exercise (TrA: 2.88 ± 0.27 cm lateral and 1.53 ± 0.47 cm anterior of vertex; MF: 3.02 ± 0.48 cm lateral and 1.62 ± 0.40 cm anterior of vertex) closely resembled that observed in healthy individuals (TrA: 2.83 ± 0.48 cm lateral and 2.00 ± 0.43 cm anterior of vertex; MF: 2.94 ± 0.43 cm lateral and 1.77 ± 0.48 cm anterior of vertex). The VAS and the ODI were reduced following the sling exercise (VAS: P < 0.001; ODI: P < 0.001).ConclusionThis study provides evidence that sling training can drive plasticity changes in the motor system, which corresponds with the reduction in pain and disability levels in patients with CLBP. This study was registered in the Chinese Clinical Trial Registry (Clinical Trial Registration Number: ChiCTR2100045904, http://www.chictr.org.cn/showproj.aspx?proj=125819).Clinical Trial RegistrationChiCTR2100045904.

QS68. Making the Diagnosis in Sagittal Craniosynostosis—It’s Height, Not Length, That Matters

Purpose: This study assesses the diagnostic reliability of a novel photogrammetric measurement to distinguish sagittal craniosynostosis (SS) from control and false positive cases (SNS). Methods: All head CT imaging at our institution between 2014-2020 was reviewed for patients with sagittal synostosis (SS, n = 177), patients with suspected sagittal craniosynostosis based on clinical examination but normal head CT (SNS, n = 30), and controls (n = 100). A novel measurement reflecting the anterior-posterior location of the vertex was measured by an angle drawn between the cranial vertex, nasion, and opisthocranion (VNO) in profile view with the head in a neutral position. NilRead Enterprise Viewer (Hyland Software, Inc. Westlake, OH) and Microsoft PowerPoint (Microsoft Corp. Redmond, Wash.) were used to measure VNO angles on 3D Head CT Reconstructions (n = 307) and clinic photos (n = 172) respectively. Three masked raters measured VNO angle on clinic photos, and one author (DYC) reviewed all photos to binarily determine the presence or absence of frontal bossing (FB) and occipital bulleting (OCB). Patients’ medical charts were reviewed for demographic information, preoperative cephalic index (CI), and operative approach when indicated. To determine the best combination of clinical findings to distinguish sagittal synostosis, Receiver operating characteristic analysis (ROC) was conducted for the various permutations of VNO, FB, OCB, and CI. Results: Mean age at pre-operative head CT was 9.5 months for the SS cohort, 4.2 months for the SNS cohort, and 8.9 months for the control cohort (p =.327). Mean age at the time of pre-operative clinical photo was 9.5 months for the SS cohort and 4.2 months for the SNS cohort (p =.149). Pearson correlations revealed no significant association between age and VNO angle for any group. The average VNO angle measured on clinical photos was 54.7°±3.8° for the SS group, 43.1°± 2.2° for the SNS group, and 41.1°± 3.7° for controls (p<.001). Three-rater analysis yielded a moderate intraclass correlation coefficient of 0.742 (p=.004). ROC analysis yielded a cut-off of 50° to determine SS versus SNS and controls. AUC for the permutations of VNO angle, FB, OCB, and CI ranged from.187 to.956. The largest AUC value of.956 was obtained when for VNO angle alone, with a corresponding sensitivity and specificity of 96.6% and 99.2% respectively. Conclusion: Measurement of the VNO angle is a reliable screening tool to diagnose sagittal craniosynostosis, with an angle of 50° or more suggesting suture synostosis. This method relies on the relationship between the anterior displacement of the cranial vertex and occipital bulleting to approach the diagnostic accuracy of CT imaging.

Making the Diagnosis in Sagittal Craniosynostosis-It's Height, Not Length, That Matters.

This study assesses the diagnostic reliability of a novel photogrammetric measurement to distinguish sagittal craniosynostosis (SS) from control and false positive cases (SNS). Head CTs from 2014-2020 were reviewed for patients with sagittal synostosis (SS, n = 177), presumed sagittal synostosis with normal imaging (SNS, n = 30), and controls (n = 100). Using preoperative clinical photographs and CTs, a measurement reflecting the anterior-posterior location of the vertexwas measured using an angle drawn betweenthe cranial vertex, nasion, andopisthocranion(VNO)in profile view,with the head in a neutralposition. Mean age at pre-operative head CT was 9.5months for the SS cohort, 4.2months for the SNS cohort, and 8.9months for controls (p = .327). Mean age at pre-operative clinical photograph was 9.5months for the SS cohort and 4.2months for the SNS cohort (p = .149). Pearson correlations revealed no significant association between age and VNO angle. The average VNO angle measured on clinical photographs was 54.7° ± 3.8° for the SS group, 43.1° ± 2.2° for the SNS group, and 41.1° ± 3.7° for controls (p < .001). Receiver operating characteristic (ROC) analysis yielded a cut-off of ≥ 50° to identify SS. Diagnostic sensitivity and specificity were 96.6% and 99.2%, respectively. Three-rater analysis yielded an average ICC of 0.742 (p = .004). Measurement of the VNO angle is a reliable screening tool to diagnose sagittal craniosynostosis, with an angle of 50° or more suggesting suture synostosis. This method relies on the relationship between the anterior displacement of the vertex and occipital bulleting to approach the diagnostic accuracy of CT imaging.

Changes in facial width according to the ostectomy level of the proximal bone segment in intraoral vertical ramus osteotomy for mandibular prognathism

BackgroundThis study aimed to investigate the changes in facial width according to the ostectomy level of the proximal segment after orthognathic surgery using intraoral vertical ramus osteotomy (IVRO) in patients with mandibular prognathism.MethodsThe participants included 32 individuals who were diagnosed with class III malocclusion prior to surgery. All participants underwent orthognathic surgery using either version of IVRO. The surgery patients were categorized into two groups depending on the type of proximal bone-segment ostectomy technique used: patients whose osteotomy height was at the level of the mandibular tooth occlusal surface (the mandibular tooth surface–level group) and patients whose osteotomy height was at the level of the mandibular inferior border (the mandibular inferior border–level group). The distances between the mandibular width and soft tissue width at the height of the sigmoid notch, mandibular foramen, and alveolar bone and at the anterior-posterior location of the mandibular condyle, mandibular foramen, and coronoid process were compared between the groups. All data were compared to identify differences between preoperative and postoperative measurements.ResultsThe postoperative change in facial soft tissue width at the intersection of the coronal plane with the coronoid process and the horizontal plane at the height of the mandibular alveolar bone in the group with osteotomy at the level of the mandibular occlusal surface differed significantly from that in the group with osteotomy at the level of the mandibular inferior border, with respective increases (mean ± SD) of 1.3 ± 3.5% and 4.7 ± 5.6%, compared to preoperative measurements (p = 0.050).ConclusionsProximal segment ostectomy at the level of the mandibular occlusal surface must be considered with regard to postoperative facial soft tissue width in vertical ramus osteotomy. Additionally, it is necessary to study the visual effect of the width of the mandible appearing small because of the posterior position of the mandible, even when the mandibular facial width is maintained.

Open and Laparoscopic Partial Nephrectomy: Comparison and Validation of Preoperative Scoring Systems, Including PADUA, RENAL, ABC Nephrometric Scores and Perinephric Fat Evaluation with Mayo Adhesive Probability Score.

PurposeTo evaluate potential associations between 4 nephrometric scoring systems, namely the PADUA (preoperative aspects and dimensions used for anatomical classification), RENAL (radius endophytic/exophytic nearness anterior posterior location), ABC (arterial-based complexity), and MAP (Mayo adhesive probability) scores and their individual components, with surgical and oncological outcomes of patients undergoing a partial nephrectomy.Materials and MethodsA consecutive, monocentric cohort of partial nephrectomy patients was retrospectively analyzed. PADUA, RENAL, ABC and MAP nephrometry scores were determined from preoperative axial images. Unadjusted and adjusted associations between overall scores, individual components, surgical approach, complications and oncological outcomes were determined using univariate and multivariate logistic regressions.ResultsA total of 189 partial nephrectomies were performed in 181 patients, via an open or a laparoscopic approach. Among scoring systems, only the MAP classification, which assesses adherent perinephric fat, was associated with severe surgical complications as well as with operative time (p<0.05). Among all components of the PADUA and RENAL scores, only proximity of the tumor to the collecting system was associated with overall surgical complication rates, while the diameter of the tumor influenced the operative time (p<0.05). The ABC score was not relevant. Male gender, antiplatelet therapy, and a laparoscopic approach were associated with higher overall surgical complication rates (p<0.05). The number of oncologic recurrences during follow-up was too low to run statistical analyses.ConclusionNephrometry scores could be simplified to predict surgical complications after partial nephrectomy. In this framework, adherent perinephric fat seemed to be strongly associated with an increased risk of surgical complications.

On the gular sac tissue of the brown pelican: Structural characterization and mechanical properties

The brown pelican (Pelecanus occidentalis) wields one of the largest bills of any bird and is distinguished by the deployable throat pouch of extensible tissue used to capture prey. Here we report on mechanical properties and microstructure of the pouch skin. It exhibits significant anisotropy, with the transverse direction having maximum nominal tensile strains of 200% to 300%, triple the value in the longitudinal direction. This is a higher extensibility than most conventional skin and is the result of the requirement of the sac to net fish; it should expand laterally, with controlled longitudinal stretch. Transmission electron microscopy provides microstructural evidence of the directionality of the collagen fibers and reveals the individual collagen fibrils with a bimodal diameter distribution having peaks at 100 and 170 nm. These dimensions are similar to collagen in mammal skin. In the lateral direction, the fibers form a curvy pattern with a radius of approximately 2 µm wherein the fibrils reorient, straighten, slide, and stretch elastically under tensile load. A second mechanism operates in the transverse direction; the membrane forms a corrugated pattern that, upon straightening of collagen fibrils, confers additional extensibility. This elicits the anisotropic response observed in tensile testing. This work focuses on the mechanical characterization based on the effect of relative bird age, sample location on the pouch, and strain rate. Anterior-posterior location and strain rate are not major influencers on exhibited strengths and extensibilities. However, bird age and dorsal-ventral location are found to affect the mechanical response of the pouch significantly. A physically-based constitutive model is developed for the middle layer of the gular sac, based on observations, which predicts maximum stresses, strains, and the shape of the stress-strain curve consistent with the experimental results.

Cabaud Memorial Award: Lateral Extra-articular Tenodesis Alters Regional Distribution of Contact Stress in the Lateral Knee Compartment under Simulated Pivoting Loads: An In Vitro Study

Objectives:Residual laxity after ACL reconstruction (ACLR) may adversely impact patient outcomes and function and has led to the increasing utilization of lateral extra-articular augmentation procedures in conjunction with ACLR and specifically, Lateral Extra-articular Tenodesis (LET). However, concerns of overconstraining the lateral compartment and subsequent increased lateral compartment contact stress and accelerated degenerative changes have been suggested with LET procedures. Therefore, the purpose of this work was to assess the impact of a LET on contact mechanics of the lateral compartment in response to multiplanar torques representing pivoting maneuvers.Methods:Nine cadaveric knees (4 male, 37.4 ± 11.6 years old) were mounted to a robotic manipulator equipped with a six-axis force-torque sensor. The robot applied multiplanar torques simulating two types of pivot shift (PS) maneuvers, subluxing the lateral compartment, at 30° of knee flexion. The following loading combinations were applied: (PS1) 8 Nm of valgus and 4 Nm of internal rotation torques; (PS2) 100 N compression force, 8 Nm valgus torque, 2 Nm internal rotation torque, and 30 N anterior force. Kinematics were recorded in the following states: ACL intact, sectioned, reconstructed and, finally, after sectioning the anterolateral ligament (ALL) and kaplan fibers and performing a LET. ACLR was performed utilizing a bone-patellar tendon-bone autograft, via medial parapatellar arthrotomy. LET was performed using a modified lemaire technique with a metal staple femoral fixation at 60° of flexion in neutral rotation. A contact stress transducer was then sutured to the tibial plateau beneath the menisci and the previously-determined kinematics were replayed, while recording the lateral compartment contact stress. At the peak applied loads, the following measures were determined in the lateral compartment: contact force, contact area, the anterior-posterior (AP) location of the center of contact stress (CCS), the mean contact stress, and the peak contact stress and its AP location. Statistical differences were assessed via one-way repeated measures ANOVA with Student-Neumen-Keuls post hoc test (p< 0.05).Results:Under combined valgus and internal rotation torques (PS1), the addition of a LET to ACLR increased lateral compartment contact force compared to the native knee by 51 ± 51 N (p = 0.035) on average. Contact area also increased by 60 ± 56 mm2 and 61 ± 58 mm2 relative to the ACL intact and ACL reconstructed knee (p ≤ 0.002), respectively. LET also shifted anteriorly the CCS by 4.6 ± 3.6 mm and 5.7 ± 3.1 mm on average relative to the ACL intact and ACL reconstructed knees (p < 0.001) (Fig. 1). No differences were detected for the mean and peak lateral compartment contact stress with the addition of LET compared to the ACL intact or ACL reconstructed knee (p> 0.854). The location of peak contact stress, however, shifted anteriorly compared to the ACL intact and ACL reconstructed knees by 6.2 ± 5.7 mm and 7.6 ± 5.4 mm (p < 0.001). (Fig.1). Similar results were observed under multiplanar torques with compression (PS2) for all outcome measures.Conclusion:In response to multiplanar torques representing pivoting maneuvers, the addition of a LET to ACLR, in the presence of compromised anterolateral tissues, did not increase lateral compartment contact stress. As contact force increased with the addition of LET, so did the contact area, likely mitigating changes in the level of contact stress. LET shifted the contact location anteriorly thereby altering regional loading of the lateral articular cartilage. Further study of the impact of changes in regional loading patterns in the lateral compartment on cartilage degeneration is warranted.Figure 1.

Test-retest reproducibility of atomic force microscopy measurements of human trabecular meshwork stiffness

Purpose: The purpose of the present study was to quantify test-retest reproducibility of measurements of stiffness of the human trabecular meshwork (HTM) by atomic force microscopy (AFM).&#x0D; Methods: Eleven 40 μm radial limbal cryostat sections from a fresh human donor rim were mounted on charged slides and rehydrated at room temperature. Stiffness at four TM locations (anterior to posterior along Schlemm’s canal) was measured by AFM. At each location, a 6 x 6 grid was sampled. Indentation points were evenly distributed over a 20 μm x 20 μm area, with a rate of one load/unload cycle per second. Measurements were then repeated for calculation of test-retest variability.&#x0D; Results: The test-retest coefficients of variation for the four measurement locations (anterior to posterior) were 24.39, 25.28, 12.74, and 14.26%, respectively, with a notable drop in the two posterior locations compared to the anterior. The test-retest coefficient for the sections was 19.17%. For the entire eye, the test-retest coefficient of variation for the measurement of the TM stiffness was 17.13%. Young’s moduli consistently decreased from anterior to posterior location.&#x0D; Conclusions: Wide regional variation suggests that single value does little to fully describe the complex array of TM stiffness levels within the eye, and future studies of TM stiffness assessed by AFM should include multiple tissue samples from each eye, with documentation of the anterior-posterior location of each measurement.

Mining Electronic Dental Records to Identify Dry Socket Risk Factors.

The goal of this study was to investigate risk factors for developing dry sockets in patients after dental extractions. Data were collected directly from electronic dental records (EDR) and were utilized for selecting dry socket cases and controls to conduct a nested case-control study. Case-control matching was based on sex, age range, maxilla-mandible location, and anterior-posterior location. From 83 self-reported health survey questions, 7 questions were found to have predictive potential based on a significant chi-squared test. Stepwise conditional logistic regression showed a statistically significant association between the development of dry socket and a history of serious illness (OR=1.4; 95% CI:1.02-1.95), cancer (OR=2.6; 95% CI:1.13-5.83), and frequent mouth sores (OR=1.9; 95% CI:1.09-3.33). These results corroborated previous reports on potential involvement of impaired immune response in dry socket development. EDR may be an important source for uncovering predictive factors that play a role in prevention and management of oral health.

Interfaces between microbes and membranes of host epithelial cells in hemipteran midguts.

Certain families of plant-feeding insects in the order Hemiptera (infraorder Pentatomomorpha) have established symbiotic relationships with microbes that inhabit specific pouches (caeca) of their midgut epithelium. The placement of these caeca in a well-delineated region at the most posterior end of the midgut bordering the hindgut is conserved in these families; in situ the convoluted midgut is predictably folded so that this caecal region lies adjacent to the anterior-most region of the midgut. Depending on the hemipteran family, caeca vary in their number and configuration at a given anterior-posterior location. At the host-microbe interface, epithelial plasma membranes of midgut epithelial cells interact with nonself antigens of microbial surfaces. In the different hemipteran species examined, a continuum of interactions is observed between microbes and host membranes. Bacteria can exist as free living cells within the midgut lumen without contacting host membranes while other host cells physically interact extensively with microbial surfaces by extending numerous processes that interdigitate with microbes; and, in many instances, processes completely envelope the microbes. The host cells can embrace the foreign microbes, completely enveloping each with a single host membrane or sometimes enveloping each with the two additional host membranes of a phagosome.

Locating the Instant Center of Rotation in the Subaxial Cervical Spine with Biplanar Fluoroscopy during In Vivo Dynamic Flexion-Extension.

BackgroundRecently, biplanar fluoroscopy is used to evaluate the cervical kinematics, especially to locate the instant center of rotation (ICR) during in vivo motion. This study aims to ascertain the ICR at each cervical segment in the sagittal plane during dynamic motion and assess the differences from previous studies.MethodsWhile three healthy subjects were performing full flexion-extension, two oblique views aligned horizontally and angled at approximately 55° were obtained by biplanar fluoroscopy. The minimum degree to detect significant movement in a helical axis model was set at 2°, and anterior-posterior and superior-inferior locations of each ICR were defined. To evaluate the possible distribution area and overlapping area of the ICR with disc space, we drew a circle by using the calculated distance between each coordination and the mean coordination of ICR as the radius.ResultsDuring flexion-extension motion, the mean superior-inferior location of the ICR became progressively more superior, except the C5–6 segment (p = 0.015), and the mean anterior-posterior location of the ICR became progressively more anterior without exception from C2–3 to C6–7 segments, but anterior-posterior ICR locations were not significantly different among segments. The overlapping area with the distribution circle of ICR was mainly located in the posterior half in the C3–4 segment, but the overlapping area was about 80% of the total disc space in C4–5 and C6–7 segments. The overlapping was more noticeable in the lower cervical segments after exclusion of the outlier data of the C5–6 segment in subject 1.ConclusionsThe ICR in the cervical spine showed a trend of moving progressively more superiorly and anteriorly and the disc space overlapping the distribution circle of ICR increased along the lower motion segments except the C5–6 segment. These findings could provide a good basis for level-specific cervical arthroplasty designs.

Insights into the Etiology of Mammalian Neural Tube Closure Defects from Developmental, Genetic and Evolutionary Studies.

The human neural tube defects (NTD), anencephaly, spina bifida and craniorachischisis, originate from a failure of the embryonic neural tube to close. Human NTD are relatively common and both complex and heterogeneous in genetic origin, but the genetic variants and developmental mechanisms are largely unknown. Here we review the numerous studies, mainly in mice, of normal neural tube closure, the mechanisms of failure caused by specific gene mutations, and the evolution of the vertebrate cranial neural tube and its genetic processes, seeking insights into the etiology of human NTD. We find evidence of many regions along the anterior–posterior axis each differing in some aspect of neural tube closure—morphology, cell behavior, specific genes required—and conclude that the etiology of NTD is likely to be partly specific to the anterior–posterior location of the defect and also genetically heterogeneous. We revisit the hypotheses explaining the excess of females among cranial NTD cases in mice and humans and new developments in understanding the role of the folate pathway in NTD. Finally, we demonstrate that evidence from mouse mutants strongly supports the search for digenic or oligogenic etiology in human NTD of all types.

The Change of Intra-cerebral CST Location during Childhood and Adolescence; Diffusion Tensor Tractography Study

Objectives: Corticospinal tract (CST) is the most important tract in motor control. However, there was no study about the change of CST location with aging. In this study, using diffusion tensor tractography (DTT), we attempted to investigate the change of CST location at cortex, corona radiata (CR) and posterior limb of internal capsule (IC) level with aging in typically developing children.Methods: We recruited 76 healthy pediatric subjects (range; 0–19 years). According to the result of DTT, the location of CST at cortex level was classified as follows; prefrontal cortex (PFC), PFC with Premotor cortex (PMC), PMC, PMC with primary motor cortex (M1), M1, M1 with Primary sensory cortex (S1). Anterior-posterior location (%) of CSTs at CR and IC level was also assessed.Results: DTT results about CSTs of 152 hemispheres from 76 subjects were obtained. The most common location of CST projection was M1 area (58.6%) including PMC with M1 (25.7%), M1 (17.8%), and M1 with S1 (15.1%). The mean age of the projection of CST showed considerably younger at anterior cortex than posterior; (PFC; 4.12 years, PFC with PMC; 6.41 years, PMC; 6.72 years, PMC with M1; 9.75 years, M1; 9.85 years, M1 with S1; 12.99 years, S1; 13.75 years). Spearman correlation showed positive correlation between age and the location of CST from anterior to posterior brain cortex (r = 0.368).Conclusion: We demonstrated that the location of CST projection is different with aging. The result of this study can provide the scientific insight to the maturation study in human brain.

Impact of Ethnicity on Tibial Morphometrics Relevant to Total Ankle Replacement

Category: Ankle Introduction/Purpose: Total ankle replacement (TAR) success has improved since first-generation implants, but patient satisfaction continues to be less than knee and hip replacements. Little is known about variations in distal tibia anatomy between genders and across ethnicities; therefore it is unclear the extent to which current TAR prostheses accommodate variability in patient size and shape. This study quantified distal tibia morphometrics relevant to TAR design, and assessed differences between ethnicities and genders. The hypotheses were: (1) The anterior-posterior (AP) location of the dwell point of the tibia is centralized; (2) The sagittal radius of curvature of the tibial articulation increases with bone size; (3) Differences in dwell point location or sagittal radii between genders and ethnicities can be attributed to size differences between those populations. Methods: Tibial CT scans were obtained from cadavers or individuals of various ethnicities (Table 1). Landmarks were defined on digital models created from the scans, including medial and lateral edges of the distal tibial articulation (Figure 1a), and sagittal contours of the articulation (Figure 1b). The articulation center was defined as the average center point of all contours (Figure 1c). The AP center and AP length at the level of a distal tibial resection for TAR were determined, and the AP offset of the articulation center was calculated (Figure 1c). Differences in metrics for each ethnic and gender group were determined using a one-way Anova (P&lt; .05) with Tukey’s method for differentiating groups. Regression fits of AP offset, average medial radius, and average lateral radius were determined. Utilizing AP length as a covariate, ANCOVA was utilized to assess differences in AP offset and sagittal radii between gender and ethnic groups (P&lt; .05). Results: Descriptive statistics for AP length, AP offset, and medial/lateral radii are shown in Table 1, with Tukey groupings assigned. The relationship between medial and lateral radius was not consistent across all groups. AP length was a significant covariate for medial and lateral radii, but not AP offset. The relationship between lateral radius and AP length was significantly impacted by ethnicity (P&lt; .001), but not by gender (P=.067) (Figure 2a). Medial radius versus AP length was significantly impacted by both ethnicity (P=.01) and gender (P&lt; .03) (Figure 2b). Conclusion: This study illustrates for the first time the complexity of anatomical variation of the distal tibia across ethnic groups and between genders. The location of the articulation center is invariant to tibia size across each ethnicity. Medial and lateral sagittal radii generally increase with bone size, but the relative radii of the medial and lateral compartments are not consistent across ethnicities. These results highlight the need for increased anatomic understanding of the distal tibia, and implications on TAR design and technique.

P600 Dominance Predicts Comprehension of Garden-Path Sentences

P600 Dominance Predicts Comprehension of Garden-Path Sentences

Prevalence and Location of Bone Bruises Associated with Anterior Cruciate Ligament Injury and Implications for Mechanism of Injury: A Systematic Review

Bone bruising is commonly observed on magnetic resonance imaging (MRI) after non-contact anterior cruciate ligament (ACL) injury. The primary objective of this study was to determine if the location and prevalence of tibial and femoral bone bruises after ACL injury can be explained by specific injury mechanism(s). The secondary objective was to determine whether the bone-bruise literature supports sex-specific injury mechanism(s). We hypothesized that most studies would report bone bruising in the lateral femoral condyle (LFC) and on the posterior lateral tibial plateau (LTP). MEDLINE, PubMed, and SCOPUS were searched for studies that reported bone bruise prevalence and location in ACL-injured subjects. Sex differences in bone-bruise patterns were assessed. Time from injury to imaging was assessed to account for confounding effects on bone-bruise size and location. Thirty-eight studies met the inclusion/exclusion criteria. Anterior-posterior location of bone bruises within the tibiofemoral compartment was assessed in 11 studies. Only five of these studies reported bone-bruise locations on both the tibia and the femur. The most common bone-bruise combination in all five studies was on the LFC and the posterior LTP. Sex differences were only assessed in three studies, and only one reported significantly greater prevalence of LTP bruising in females. Bone-bruise patterns in the current literature support a valgus-driven ACL injury mechanism; however, more studies should report the specific locations of tibialandfemoral bone bruises. There is insufficient evidence in the literature to determine whether there are sex-specific bone-bruise patterns in ACL-injured subjects.

The relationship between peak knee extension at heel-strike of walking and the location of thickest femoral cartilage in ACL reconstructed and healthy contralateral knees

Reports that knee cartilage health is sensitive to kinematic changes, combined with reports of extension loss following ACL reconstruction, underscores the importance of restoring ambulatory knee extension in the context of preventing premature osteoarthritis. The purpose of this study was to test the relationship between individual variations in peak knee extension at heel-strike of walking and the anterior–posterior location of thickest cartilage in the medial and lateral femoral condyles of healthy contralateral and ACL reconstructed knees. In vivo gait analysis and knee MR images were collected from 29 subjects approximately 2 years after unilateral ACL reconstruction. Knee extension was measured at heel-strike of walking and 3-D femoral cartilage thickness models were reconstructed from MR images. The ACL reconstructed knees had significantly reduced knee extension (−1.5±4.2°) relative to the contralateral knees (−4.6±3.4°) at heel-strike of walking but did not have side-to-side differences in the anterior–posterior location or magnitude of thickest medial and lateral femoral cartilage. The anterior–posterior location of the thickest medial femoral cartilage was correlated with knee extension at heel-strike in both the healthy contralateral (R2=0.356, p<0.001) and reconstructed (R2=0.234, p=0.008) knees. These results suggest that ACL reconstruction can impair terminal extension at periods of ambulatory loading known to be related to cartilage morphology in healthy joints. The fact that the femoral cartilage thickness distribution had not changed at 2 years post-op, even in the subset of subjects with extension loss, suggests that loads may be shifted to thinner cartilage regions, which could have important implications on long-term joint health.