Anterior-posterior Research Articles

Trueness of 3-dimensionally printed complete arch implant analog casts

Statement of problemAlthough a completely digital workflow has numerous advantages, a physical definitive cast may be especially helpful for the accurate assembly of components of complex complete arch-fixed prostheses, the evaluation of esthetic and occlusion features, or prosthesis fabrication. Research on the accuracy of additive complete arch casts with implants positioned with a large anterior-posterior (A-P) spread is sparse. PurposeThe purpose of this in vitro study was to evaluate the trueness of complete arch 4-implant analog casts with a large A-P distribution fabricated with different 3-dimensional (3D) printers. Material and methodsTen systems were evaluated representing currently available printing technologies and materials for the additive fabrication of complete arch 4-implant analog casts and compared for deviations in the X-, Y-, and Z-axes from the master model scan (MMS), recorded in standard tessellation language (STL). The MMS was provided to the laboratory selected by the manufacturer, permitting them to create their specific cast with computer-aided design and computer-aided manufacture specific to a particular system, including analog receptacle offset settings. Laboratories fabricated N=10 casts and affixed analogs. A conventional splinted impression and stone cast (CON) was fabricated as a control. The casts were scanned with a precision laboratory scanner (D2000; 3Shape A/S), and files were imported into the Convince metrology software program (3Shape A/S) for comparison with the MMS for mean deviations in the X-, Y-, and Z- axes. A 2-way ANOVA and the Tukey HSD comparison tests were performed between system groups and the 4 implant locations (α=.05). Comparative color maps were used to determine dimensional changes of the edentulous ridges. ResultsFor 2-dimensional deviations from the MMS in each of the 3 axes, the printer type, implant location, and interaction between those 2 variables were found to be statistically significant (P<.05). Comparisons among printers showed the smallest deviations for Asiga Pro 4K (ASG) and Stratasys Origin One (ORI) printers in both the X- and Y-axes and for CON in the Z-axis. For 3D deviations, comparison among printers indicated that ORI, SprintRay Pro55 S (SPR), and Ackuretta SOL (ACK) had the largest deviations, whereas CON and ASG showed the smallest deviations. Comparison color mapping demonstrates a disparity between printed model dimensional changes and implant analog positioning since the color maps of the casts’ ridge crests were not in concordance with the results of the implant analog deviations. ConclusionsASG, 3D Systems ProJet MJP 2500 Plus (MJP), 3D Systems NextDent 5100 (NEX), Stratasys J5 DentaJet (PJ5), Ivoclar PrograPrint PR5 (PR5), and Prodways ProMaker LD20 (PWY) were similar in terms of 3D deviations to the conventional stone cast control. Comparative color mapping showed the direction and quantity of the dimensional changes of the ridge crest frequently did not correlate with the 3D deviations of implant analog positioning. Implant analog insertion errors were predominantly responsible for analog position 3D deviations rather than the polymerization shrinkage of additive photopolymers.

A Novel Setup Technique for Radiation Treatment of a Severely Obese Patient With a Primary Brain Tumor.

Modern external beam radiation therapy (EBRT) techniques rely on the accurate positioning of the patient using the treatment couch. These motorized couches have weight limits that have decreased over time and are not able to support severely obese patients requiring EBRT. We aimed to develop a technique to support obese patients who are above their weight tolerance while accurately delivering radiation treatment to a brain tumor. This technique was used on a patient receiving adjuvant radiation for gliosarcoma, a variant of glioblastoma. The patient was CT scanned, and the 3D conformal radiation therapy plan was created. A custom treatment couch was created using a transport stretcher, Styrofoam, a CT couch-top, and an IMRT board, which allowed for a thermoplastic mask to be used for a reproducible setup. AP and lateral portal films were taken prior to each treatment to confirm the accuracy of the manual daily setup of the patient on the custom couch. The patient received 60 Gy in 30 daily fractions of 3DCRT in a reproducible fashion. The average deviation from the isocenter fell within the 10 mm and 8 mm planning margins applied to the clinical target volume (CTV) for the initial and boost fields, respectively. The average daily shifts in the anterior-posterior (AP) direction for the patient were 7.97 (-16.19 to 12.04) mm and 1.98 mm (-1.1 to 4.3) mm for the initial and boost treatments, respectively. The average daily shifts in the superior-inferior (SI) direction were 2.2 (-5.08 to 9.04) mm and 3.88 (-2.9 to 8.0) mm for the initial and boost treatments, respectively. This novel approach allowed treatment at 60 Gy for a gliosarcoma patient who had previously been denied treatment due to his weight. By utilizing readily available materials within the department, our team was able to create a reproducible setup technique to safely treat the patient.

Clinician accuracy in identifying essential laryngeal landmarks on swallowing fluoroscopy.

Identification of anatomical landmarks is essential for interpretation of video fluoroscopic swallow studies (VFSS). This investigation sought to confirm the location of essential laryngeal landmarks and determine clinician accuracy in structure identification on VFSS. A single human cadaver was used to generate unmarked standard lateral and anterior-posterior (AP) fluoroscopic images. Essential laryngeal structures (e.g., true vocal fold, arytenoid) were directly identified using a guidewire placed through an endoscope while obtaining corresponding marked fluoroscopic images. Licensed clinicians (speech-language pathologists [SLP], laryngologists) and trainees (otolaryngology residents, SLP clinical fellows [CF]) identified 18 structures (9 lateral, 9 AP) on unmarked images. Answers were compared to corresponding marked images. The percentage of accurate identification was calculated for each clinician and then compared between groups using t-tests. Twenty-four individuals (10 SLPs, 1 CF, 9 residents, 4 laryngologists) from six institutions completed structure identification. Mean overall accuracy was 41.7 ± 13.0% (range 18.8-68.8%). There were no significant differences in mean overall accuracy between trainees (41.9 ± 12.9%) and clinicians (42.0 ± 13.1%), p = .97, or between SLPs (45.5 ± 12.8%) and physicians (38.9 ± 12.3%), p = .22. On average, participants were significantly more accurate identifying structures on lateral view (53.1 ± 16.1%) than AP (27.3 ± 22.8%), p < .001. Less than half of participants accurately identified the laryngeal ventricle, cricoid, epiglottic petiole, and the anterior commissure on lateral view. The ability of certified clinicians and trainees to correctly identify essential anatomic landmarks on swallowing fluoroscopy may be poor. Future work is needed to identify how we can train clinicians on more accurate identification of essential anatomic structures on swallowing fluoroscopy.Level of Evidence: NA.

Effect of current direction and muscle activation on motor cortex neuroplasticity induced by repetitive paired-pulse transcranial magnetic stimulation.

Repetitive paired-pulse transcranial magnetic stimulation (TMS) at indirect (I)-wave periodicity (iTMS) can increase plasticity in primary motor cortex (M1). Both TMS coil orientation and muscle activation can influence I-wave activity, but it remains unclear how these factors influence M1 plasticity with iTMS. We therefore investigated the influence of TMS coil orientation and muscle activation on the response to iTMS. Thirty-two young adults (24.2 ± 4.8years) participated in three experiments. Each experiment included two sessions using a modified iTMS intervention with either a posterior-anterior orientation (PA) or anterior-posterior (AP) coil orientation over M1. Stimulation was applied in resting (Experiments 1 and 3) or active muscle (Experiments 2 and 3). Effects of iTMS on M1 excitability were assessed by recording motor evoked potentials (MEPs) and short-interval intracortical facilitation (SICF) with PA and AP orientations in both resting (all experiments) and active (Experiment 2) muscle. For the resting intervention, MEPs were greater after AP iTMS (Experiment 1, P = .046), whereas SICF was comparable between interventions (all P > .10). For the active intervention, responses did not vary between PA and AP iTMS (Experiment 2, all P > .14), and muscle activation reduced the effect of AP iTMS during the intervention (Experiment 3, P = .002). Coil orientation influenced the MEP response after iTMS, and muscle activation reduced the response during iTMS. While this suggests that AP iTMS may be beneficial in producing a neuroplastic modulation of I-wave circuits in resting muscle, further exploration of factors such as dosing is required.

Standard versus innovative robotic balance assessment for people with multiple sclerosis: a correlational study

IntroductionBalance disorders are common in people with Multiple Sclerosis (PwMS) and, together with other impairments and disabilities, often prevent PwMS from performing their daily living activities. Besides clinical scales and performance tests, robotic platforms can provide more sensitive, specific, and objective monitoring. Validated technologies have been adopted as gold standard, but innovative robotic solutions would represent an opportunity to detect balance impairment in PwMS.AimStudy’s aim was to compare postural assessment of 46 PwMS with a relapsing–remitting form during static tasks performed with the novel robotic platform hunova® and the gold standard EquiTest®,MethodsPearson’s r was run on Center of Pressure (COP)-related parameters and global static balance measures computed from hunova® and EquiTest® in eyes-open (EO) and eyes-closed (EC) conditions. In addition, agreeableness level toward the use of both devices was tested through numeric rating scale.ResultsConsidering COP-related parameters, correlations were significant for all measures (p < .001). Interestingly, in EO, a strong correlation was shown for sway area (r = .770), while Medio-Lateral (ML) and Anterior–Posterior (AP) oscillation range, path length, ML and AP speed, ML and AP root mean square distance had a relatively strong association (.454 ≤ r ≤ .576). In EC, except for ML oscillation range showing a relatively strong correlation (r = .532), other parameters were strongly associated (.603 ≤ r ≤ .782). Correlations between global balance indexes of hunova® and EquiTest® revealed a relatively strong association between the Somatosensory Score in EquiTest® and the Somatosensory Index in hunova® (r = − .488). While in EO Static Balance Index from hunova® was highly correlated with Equilibrium score of EquiTest® (r = .416), Static Balance Index had a relatively strong association with both the Equilibrium (r = .482) and Strategy Score (r = .583) of EquiTest® in EC. Results from agreeableness rating scale revealed that hunova® was highly appreciated compared to EquiTest® (p = .044).Conclusionshunova® represents an innovative adjunct to standard robotic balance evaluation for PwMS. This confirms that combining traditional and robotic assessments can more accurately detect balance impairments in MS.

Efficacy of Varying Surgical Approaches on Achieving Optimal Alignment in Adult Spinal Deformity Surgery.

The Roussouly, SRS-Schwab, and GAP classifications define alignment by spinal shape and deformity severity. The efficacy of different surgical approaches and techniques to successfully achieve these goals is not well understood. Identify the impact of surgical approach and/or technique on meeting complex realignment goals in adult spinal deformity(ASD) corrective-surgery. Retrospective. Included: ASD patients fused to pelvis with two-year(2Y) data. Patients were categorized by: 1)Roussouly: matching current and theoretical spinal shapes; 2)improving in SRS-Schwab modifiers(0, +, ++); 3)improving GAP Proportionality by 2Y. ANCOVA and multivariable logistic regression analyses controlling for age, levels fused, baseline deformity, and three-column osteotomy usage compared the effect of different surgical approaches, interbody and osteotomy use on meeting realignment goals. 693 ASD patients were included. By surgical approach, 65.7% were posterior-only and 34.3% underwent anterior-posterior(AP) approach with 76% receiving an osteotomy(21.8% 3CO). By 2Y, 34% matched Roussouly, 58% improved in GAP, 45% in SRS-Schwab PT, 62% SVA, and 70% PI-LL. Combined approaches were most effective for improvement in PT(OR: 1.7,[1.1-2.5]) and GAP(OR: 2.2,[1.5-3.2]). Specifically, ALIFs below L3 demonstrated higher rates of improvement versus TLIFs in Roussouly(OR: 1.7, [1.1-2.5]) and GAP(OR: 1.9, [1.3-2.7]). Patients undergoing PSO at L3 or L4 were more likely to improve in PT(OR: 2.0,[1.0-5.2]) and PI-LL(OR: 3.8[1.4-9.8]). Clinically, patients undergoing combined approach demonstrated higher rates of meeting SCB in ODI by 2Y while minimizing rates of PJF, most often with an ALIF at L5-S1(ODI-SCB: OR: 1.4,[1.1-2.0];PJF: OR: 0.4,[0.2-0.8]). Among patients undergoing ASD realignment, optimal lumbar shape and proportion can be achieved more often with a combined approach. While TLIFs incorporating a three-column osteotomy at L3 and L4 can restore lordosis and normalize pelvic compensation, ALIFs at L5-S1 were most likely to achieve complex realignment goals with an added clinical benefit and mitigation of junctional failure.

Integrating biplane information and context for spine landmark detection.

Spine landmark detection is of great significance for spinal morphological parameter assessment and three-dimensional reconstruction of the human spine. This detection task generally involves locating spine landmarks in the anterior-posterior (AP) and lateral (LAT) X-rays of the spine. Recently, the two-stage methods for AP spine landmark detection achieve better performance. However, these methods perform poorly in LAT landmark detection because of poor detection accuracy of LAT vertebra due to occlusion. To solve this problem, this paper proposes a new two-stage spine landmark detection method. In the first stage, this paper propose a biplane vertebra detection network for vertebra detection on AP and X-rays simultaneously. Then an epipolar module and a context enhancement module are proposed to assist LAT vertebra detection by using the biplane information and the context information of the vertebrae respectively. In the second stage, the landmarks can be obtained in the detected vertebrae area. Extensive experiment results conducted on a dataset containing 328 pairs of X-rays demonstrate that our method improves the vertebra and landmark detection accuracy.

Feasibility of Cerebellar Measurements with Phased Array Sonography through the Anterior Fontanelle in Comparison to MRI.

Cerebral sonography (CS) through the anterior fontanelle is a neonatal brain imaging method that has become an integral part of modern neonatal bedside care for both screening and diagnostic purposes. Premature infants with cognitive delay have a reduction in cerebellar size at term corrected age on magnetic resonance imaging (MRI). We aimed to determine the level of agreement between postnatal MRI and CS for cerebellar biometry and to determine the level of agreement within one and between different examiners. Cerebellar sonography and MRI measurements of the cerebellum from 30 term infants was assessed by Bland-Altman plots. Measurements between both modalities were compared using Wilcoxon's signed rank test. A p-value < 0.01 was considered statistically significant. Intraclass correlation coefficients (ICC) for intra- and interrater reliabilities of CS measurements were calculated. There was no statistically significant difference between CS and MRI for linear measurements, but the measurements of perimeter and surface area differed significantly between the two techniques. There was a systematic bias between both modalities for most measurements except for anterior-posterior (AP) width and vermis height (VH). For measurements that were not statistically different from MRI, we found excellent intrarater ICC for the AP width, VH, and cerebellar width. The interrater ICC was excellent for the AP width and VH, but poor for the transverse cerebellar width. With a strict imaging protocol, cerebellar measurements of the AP width and the VH can be used as an alternative to MRI for diagnostic-screening purposes in a neonatal department where multiple clinicians perform bedside CS. · Abnormal cerebellar growth and injuries affect neurodevelopmental outcome.. · Cerebral sonography through the anterior fontanelle is used for bedside imaging.. · Postnatal sonographic cerebellar measurements are not validated against MRI.. · Measuring vermis height and anterior-posterior width are reliable.. · Measuring transverse cerebellar width through anterior fontanelle is unreliable..

Diagnosis of Latent Tuberculosis Infection in Hemodialysis Patients: TST versus T-SPOT.TB.

Hemodialysis (HD) patients should be screened for latent tuberculosis (TB) infection. We aimed to determine the frequency of latent TB infection in HD patients and to compare the effectiveness of the tests used. The files of 56 HD patients followed between 1 January 2021 and 1 October 2022 were retrospectively analyzed. Demographic data, the presence of the Bacillus Calmette-Guerin (BCG) vaccine, whether or not the patients had previously received treatment for TB before, the status of encountering a patient with active TB of patients over 18 years of age, without active tuberculosis and who had a T-SPOT.TB test or a Tuberculin Skin Test (TST) were obtained from the patient files. The presence of previous TB in a posterior-anterior (PA) chest X-ray was obtained by evaluating PA chest X-rays taken routinely. Of the patients, 60.7% (n = 34) were male and their mean age was 60.18 ± 14.85 years. The mean duration of dialysis was 6.43 ± 6.03 years, and 76.8% (n = 43) had 2 BCG scars. The T-SPOT.TB test was positive in 32.1% (n = 18). Only 20 patients (35.7%) had a TST and all had negative results. While the mean age of those with positive T-SPOT.TB results was higher (p = 0.003), the time taken to enter HD was shorter (p = 0.029). T-SPOT.TB test positivity was higher in the group that had encountered active TB patients (p = 0.033). However, no significant difference was found between T-SPOT.TB results according to BCG vaccine, albumin, urea and lymphocyte levels. Although T-SPOT.TB test positivity was higher in patients with a previous TB finding in a PA chest X-ray, there was no statistically significant difference (p = 0.093). The applicability of the TST in the diagnosis of latent TB infection in HD patients is difficult and it is likely to give false-negative results. The T-SPOT.TB test is not affected by the BCG vaccine and immunosuppression. Therefore, using the T-SPOT.TB test would be a more appropriate and practical approach in the diagnosis of latent TB in HD patients.

How enhancers regulate wavelike gene expression patterns.

A key problem in development is to understand how genes turn on or off at the right place and right time during embryogenesis. Such decisions are made by non-coding sequences called 'enhancers.' Much of our models of how enhancers work rely on the assumption that genes are activated de novo as stable domains across embryonic tissues. Such a view has been strengthened by the intensive landmark studies of the early patterning of the anterior-posterior (AP) axis of the Drosophila embryo, where indeed gene expression domains seem to arise more or less stably. However, careful analysis of gene expression patterns in other model systems (including the AP patterning in vertebrates and short-germ insects like the beetle Tribolium castaneum) painted a different, very dynamic view of gene regulation, where genes are oftentimes expressed in a wavelike fashion. How such gene expression waves are mediated at the enhancer level is so far unclear. Here, we establish the AP patterning of the short-germ beetle Tribolium as a model system to study dynamic and temporal pattern formation at the enhancer level. To that end, we established an enhancer prediction system in Tribolium based on time- and tissue-specific ATAC-seq and an enhancer live reporter system based on MS2 tagging. Using this experimental framework, we discovered several Tribolium enhancers, and assessed the spatiotemporal activities of some of them in live embryos. We found our data consistent with a model in which the timing of gene expression during embryonic pattern formation is mediated by a balancing act between enhancers that induce rapid changes in gene expression patterns (that we call 'dynamic enhancers') and enhancers that stabilize gene expression patterns (that we call 'static enhancers'). However, more data is needed for a strong support for this or any other alternative models.

Posterior cruciate ligament retention with medial ball-in-socket conformity promotes internal tibial rotation and knee flexion while providing high clinical outcome scores

BackgroundAlthough retaining the posterior cruciate ligament (PCL) is advantageous in unrestricted kinematically aligned TKA, it is often excised with a medial stabilized implant. The primary objectives were to determine whether PCL retention using an insert with ball-in-socket (B-in-S) medial conformity to maximize A-P stability promotes internal tibial rotation and flexion while providing high patient-reported outcome scores. MethodsTwo cohorts of 25 patients each were treated with unrestricted kinematically aligned (KA) TKA using a tibial insert with B-in-S medial conformity and a flat lateral articular surface. One cohort retained the PCL; the other had it excised. Patients performed deep knee bend and step-up exercises during fluoroscopic imaging. Following 3D model-to-2D image registration, anterior-posterior (A-P) positions of the femoral condyles and tibial rotation were determined. ResultsFor deep knee bend, mean internal tibial rotation with PCL retention was significantly greater at maximum flexion (17.7° ± 5.7° versus 10.4° ± 6.5°, p < 0.001) and significantly greater at 30°, 60°, and 90° flexion as well (p ≤ 0.0283). For step-up, mean internal tibial rotation with PCL retention was significantly greater at at 15°, 30°, and 45° flexion (p ≤ 0.0049) but was marginally not significantly greater at 60° (i.e. maximum) flexion (12.3° ± 4.4° versus 10.1° ± 5.4°, p = 0.0794). Mean flexion during active knee flexion with PCL retention was significantly greater (127° ± 8° versus 122° ± 6°, p = 0.0400). Both cohorts had high median Oxford Knee, WOMAC, and Forgotten Joint Scores that were not significantly different (p = 0.0918, 0.1448, and 0.0855, respectively) ConclusionSurgeons that perform unrestricted KA TKA should retain the PCL with an insert that has B-in-S medial conformity, as this maintains extension and flexion gaps while also promoting internal tibial rotation and knee flexion as well as providing high clinical outcome scores.

Surface guidance compared with ultrasound-based monitoring and diaphragm position in cone-beam computed tomography during abdominal stereotactic radiotherapy in breath-hold.

Spirometry induced deep-inspiration-breath-hold (DIBH) reduces intrafractional motion during upper abdominal stereotactic body radiotherapy (SBRT). The aim of this prospective study was to evaluate whether surface scanning (SGRT) is an adequate surrogate for monitoring residual internal motion during DIBH. Residual motion detected by SGRT was compared with experimental 4D-ultrasound (US) and an internal motion detection benchmark (diaphragm-dome-position in kV cone-beam computed tomography (CBCT) projections). Intrafractional monitoring was performed with SGRT and US in 460 DIBHs of 12 patients. Residual motion detected by all modalities (SGRT (anterior-posterior (AP)), US (AP, craniocaudal (CC)) and CBCT (CC)) was analyzed. Agreement analysis included Wilcoxon signed rank test, Maloney and Rastogi's test, Pearson's correlation coefficient (PCC) and interclass correlation coefficient (ICC). Interquartile range was 0.7mm (US(AP)), 0.8mm (US(CC)), 0.9mm (SGRT) and 0.8mm (CBCT). SGRT(AP) vs. CBCT(CC) and US(CC) vs. CBCT(CC) showed comparable agreement (PCCs 0.53 and 0.52, ICCs 0.51 and 0.49) with slightly higher precision of CBCT(CC). Most agreement was observed for SGRT(AP) vs. US(AP) with largest PCC (0.61) and ICC (0.60), least agreement for SGRT(AP) vs. US(CC) with smallest PCC (0.44) and ICC (0.42). Residual motion detected during spirometry induced DIBH is small. SGRT alone is no sufficient surrogate for residual internal motion in all patients as some high velocity motion could not be detected. Observed patient-specific residual errors may require individualized PTV-margins.

What Is the Role of Sustained Visual Attention in the Maintenance of Postural Control in Young Adults?

Dual tasks requiring sustained visual attention and upright stance are common, yet their impact on standing balance is not well understood. We investigated the role of visual attention in the maintenance of postural control, using the multiple-object tracking (MOT) task. Healthy young adults (n = 12) performed the MOT task at three object movement speeds while seated or standing. MOT performance was assessed using tracking capacity (k). Metrics calculated to assess mediolateral (ML) and anterior-posterior (AP) postural control included: maximum difference between CoM and CoP position (CoM-CoP Max), root mean square distance for center of pressure and center of mass position (CoP and CoM RMS distance), and correlation between CoM and CoP time series signals (CoM/CoP correlation). As predicted, k decreased significantly as object movement speed increased for both standing and seated conditions. Object movement speed also significantly affected AP CoM-CoP Max in seated conditions (p = .021) and AP CoM/CoP correlation for standing conditions (p = .002). The results demonstrate utility of the MOT task in understanding the role of visual attention in postural control, even though healthy young adults were able to compensate for the addition of a sustained visual attention task, with minimal deficits to postural control.

Accuracy Evaluation Trial of Mixed Reality-Guided Spinal Puncture Technology.

To evaluate the accuracy of mixed reality (MR)-guided visualization technology for spinal puncture (MRsp). MRsp involved the following three steps: 1. Lumbar spine computed tomography (CT) data were obtained to reconstruct virtual 3D images, which were imported into a HoloLens (2nd gen). 2. The patented MR system quickly recognized the spatial orientation and superimposed the virtual image over the real spine in the HoloLens. 3. The operator performed the spinal puncture with structural information provided by the virtual image. A posture fixation cushion was used to keep the subjects' lateral decubitus position consistent. 12 subjects were recruited to verify the setup error and the registration error. The setup error was calculated using the first two CT scans and measuring the displacement of two location markers. The projection points of the upper edge of the L3 spinous process (L3↑), the lower edge of the L3 spinous process (L3↓), and the lower edge of the L4 spinous process (L4↓) in the virtual image were positioned and marked on the skin as the registration markers. A third CT scan was performed to determine the registration error by measuring the displacement between the three registration markers and the corresponding real spinous process edges. The setup errors in the position of the cranial location marker between CT scans along the left-right (LR), anterior-posterior (AP), and superior-inferior (SI) axes of the CT bed measured 0.09 ± 0.06 cm, 0.30 ± 0.28 cm, and 0.22 ± 0.12 cm, respectively, while those of the position of the caudal location marker measured 0.08 ± 0.06 cm, 0.29 ± 0.18 cm, and 0.18 ± 0.10 cm, respectively. The registration errors between the three registration markers and the subject's real L3↑, L3↓, and L4↓ were 0.11 ± 0.09 cm, 0.15 ± 0.13 cm, and 0.13 ± 0.10 cm, respectively, in the SI direction. This MR-guided visualization technology for spinal puncture can accurately and quickly superimpose the reconstructed 3D CT images over a real human spine.

Symmetry in knee arthrokinematics in healthy collegiate athletes during fast running and drop jump revealed through dynamic biplane radiography

Changes in cartilage contact area and/or contact location after knee injury can initiate and exacerbate cartilage degeneration. Typically, the contralateral knee is used as a surrogate for native cartilage contact patterns on the injured knee. However, symmetry in cartilage contact patterns between healthy knees during high-impact activities is unknown. Tibiofemoral kinematics were measured on 19 collegiate athletes during fast running and drop jump using dynamic biplane radiography and a validated registration process that matched computed tomography (CT)-based bone models to the biplane radiographs. Cartilage contact area and location were measured with participant-specific magnetic resonance imaging (MRI)-based cartilage models superimposed on the CT-based bone models. Symmetry in cartilage contact area and location was assessed by the absolute side-to-side differences (SSD) within participants. The SSD in contact area during running (7.7±6.1% and 8.0±4.6% in the medial and lateral compartments, respectively) was greater than during drop jump (4.2±3.7% and 5.7±2.6%, respectively) (95% CI of the difference: medial [2.4%, 6.6%], lateral [1.5%, 4.9%]). The average SSD in contact location was 3.5mm or less in the anterior-posterior (AP) direction and 2.1mm or less in the medial-lateral (ML) direction on the femur and tibia for both activities. The SSD in AP contact location on the femur was greater during running than during drop jump (95% CI of the difference: medial [1.6mm, 3.6mm], lateral [0.6mm, 1.9mm]). This study provides context for interpreting results from previous studies on tibiofemoral arthrokinematics. Previously reported differences between ligament-repaired and contralateral knee arthrokinematics fall within the range of typical SSDs observed in healthy athletes. Previously reported arthrokinematics differences that exceed SSDs found in these healthy athletes occur only in the presence of anterior cruciate ligament(ACL) deficiency or meniscectomy.

Early Postoperative Activities of Daily Living Do Not Adversely Affect Joint Torques or Translation Regardless of Capsular Condition: A Cadaveric Study

To evaluate the impact of capsular management on joint constraint and femoral head translations during simulated activities of daily living (ADL). Using 6 (n= 6) cadaveric hip specimens, the effect of capsulotomies and repair was then evaluated during simulated ADL. Joint forces and rotational kinematics associated with gait and sitting, adopted from telemeterized implant studies, were applied to the hip using a 6-degrees of freedom (DOF) joint motion simulator. Testing occurred after creation of portals, interportal capsulotomy (IPC), IPC repair, T-capsulotomy (T-Cap), partial T-Cap repair, and full T-Cap repair. The anterior-posterior (AP), medial-lateral (ML), and axial compression DOFs were operated in force control, whereas flexion-extension, adduction-abduction, and internal-external rotation were manipulated in displacement control. Resulting femoral head translations and joint reaction torques were recorded and evaluated. Subsequently, the mean-centered range of femoral head displacements and peak signed joint restraint torques were calculated and compared. During simulated gait and sitting, the mean range of AP femoral head displacements with respect to intact exceeded 1% of the femoral head diameter after creating portals, T-Caps, and partial T-Cap repair (Wilcoxon signed rank P < .05); the mean ranges of ML displacements did not. Deviations in femoral head kinematics varied by capsule stage but were never very large. No consistent trends with respect to alterations in peak joint restrain torques were observed. In this cadaveric biomechanical study, capsulotomy and repair minimally affected resultant femoral head translation and joint torques during simulated ADLs. The tested ADLs appear safe to perform after surgery, regardless of capsular status, because adverse kinematics were not observed. However, further study is required to determine the importance of capsular repair beyond time-zero biomechanics and the resultant effect on patient-reported outcomes.

The relationship between cervical spine range of motion and postural sway in mechanical neck pain: A cross-sectional study.

Impairments in postural sway have been identified in people with mechanical neck pain. The influence of cervical spine range of motion (ROM) on postural sway is unclear in mechanical neck pain (MNP). This study investigated the relationship between cervical spine range of motion (ROM) and postural sway in MNP. The cervical ROM was measured using the Cervical Range of Motion (CROM) device. Standing postural sway characterised by mean centre of pressure (COP) measurements in the anterior posterior (AP) and medio-lateral direction with eyes closed and feet together condition was recorded on a posturography platform. Pearson product moment correlation coefficient was used to identify the relationship between cervical ROM and postural sway. Seventy-two MNP individuals (Mean age: ) of either sex (Male: ) were recruited. Overall, no statistically significant correlations were identified between cervical spine ROM in sagittal and frontal plane and postural sway (r values ranging from 0.00 to ; p-values ). However, a weak negative correlation was present between the cervical rotation and AP (r-; p-) and mediolateral (r-; p-) COP excursion. The cervical spine ROM was found to have a weak relationship with postural sway in individuals with MNP. This suggests the investigation of other mechanisms especially muscle tension which might be responsible for altered postural sway in MNP.

Postural stability measures in healthy miniature Dachshunds obtained using a pressure mat and a force platform: a validity and reliability study

BackgroundMiniature Dachshunds have a high prevalence of neurological and musculoskeletal diseases potentially affecting their balance. The postural stability of dogs in quiet standing is an indicator of postural control and can aid in diagnosing and monitoring lameness and other pathologies affecting balance. Measures of centre of pressure (CoP) can be obtained from force and pressure platform systems to evaluate postural stability, however the two systems have not been compared and the latter has not been validated in dogs. The aims of this study were to assess the validity and reliability of using a pressure mat compared to a force platform and report normative values of CoP measures in healthy miniature Dachshunds. Forty two healthy miniature Dachshunds of smooth, long and wire-haired breed types stood still on a pressure mat (Tekscan MatScan®) placed on a force platform and the two systems were synchronised. Maximum anterior-posterior (AP) and medial-lateral (ML) ranges, sway path and 95% area of a best-fit ellipse were computed. Bland-Altman plots and coefficients of correlation assessed validity; intra-class correlation coefficients (ICC) assessed inter-test reliability for both systems. Non-linear regression analyses were used to describe the relationship between CoP and demographic measures.ResultsStrong correlations for AP range, ML range and 95% ellipse area and moderate correlation for sway path were found between the two devices. ICC showed good reliability (0.75–0.90) for AP range and moderate (0.5–0.75) for ML range and the 95% ellipse area for both devices. Sway path reliability was excellent (> 0.90) with the force platform but moderate with the pressure mat. Age was positively correlated with balance (inversely correlated with all measures except sway path), while weight explained 94% (force platform) and 27% (pressure mat) of the variance in sway path.ConclusionsPressure mats can be used to obtain valid and reliable measures of CoP and replace use of force platforms. Older (non-senior) and heavier (non-obese) dogs show better postural stability. Clinical examinations should include the use of a range of CoP measures when assessing postural balance, while accounting for the effects of age and body weight.

Single-cell expression profile of Drosophila ovarian follicle stem cells illuminates spatial differentiation in the germarium

BackgroundHow stem cell populations are organized and regulated within adult tissues is important for understanding cancer origins and for developing cell replacement strategies. Paradigms such as mammalian gut stem cells and Drosophila ovarian follicle stem cells (FSC) are characterized by population asymmetry, in which stem cell division and differentiation are separately regulated processes. These stem cells behave stochastically regarding their contributions to derivative cells and also exhibit dynamic spatial heterogeneity. Drosophila FSCs provide an excellent model for understanding how a community of active stem cells maintained by population asymmetry is regulated. Here, we use single-cell RNA sequencing to profile the gene expression patterns of FSCs and their immediate derivatives to investigate heterogeneity within the stem cell population and changes associated with differentiation.ResultsWe describe single-cell RNA sequencing studies of a pre-sorted population of cells that include FSCs and the neighboring cell types, escort cells (ECs) and follicle cells (FCs), which they support. Cell-type assignment relies on anterior–posterior (AP) location within the germarium. We clarify the previously determined location of FSCs and use spatially targeted lineage studies as further confirmation. The scRNA profiles among four clusters are consistent with an AP progression from anterior ECs through posterior ECs and then FSCs, to early FCs. The relative proportion of EC and FSC clusters are in good agreement with the prevalence of those cell types in a germarium. Several genes with graded profiles from ECs to FCs are highlighted as candidate effectors of the inverse gradients of the two principal signaling pathways, Wnt and JAK-STAT, that guide FSC differentiation and division.ConclusionsOur data establishes an important resource of scRNA-seq profiles for FSCs and their immediate derivatives that is based on precise spatial location and functionally established stem cell identity, and facilitates future genetic investigation of regulatory interactions guiding FSC behavior.

Congenital Anterior Dislocation of the Sacrococcygeal Bone in a Newborn.

We present a case of a child who was transported to the Neurosurgery Clinic from another hospital for the purpose of performing a surgical procedure of the spinal myelomeningocele. On the first day of the stay, a set of tests was performed, including an anterior-posterior (AP) projection X-ray, which clearly showed a developmental defect in the lumbar-sacral section of the spine. In the follow-up physical examination, there was a depression of the skin on the right side of the surgical scar after closing the open myelomeningocele. In the follow-up MRI of the lumbar-sacral section, an extremely rare congenital anterior dislocation of the sacrococcygeal bone was unexpectedly visualized. Despite recommendations for further diagnostics, the patient did not attend the required follow-up examinations. In the final section, we provide a general summary of the literature on rare developmental defects of the spine in children.