Patient and Surgical Variability Influences Loading Across Metatarsal Osteotomy

Second metatarsal osteotomies for metatarsalgia: A robotic cadaveric study of the effect of osteotomy plane and metatarsal shortening on plantar pressure

Background: MR imaging of the spinal cord (SC) gray matter (GM) at the cervical and lumbar enlargements' level may be particularly informative in lower motor neuron disorders, e. g., spinal muscular atrophy, but also in other neurodegenerative or autoimmune diseases affecting the SC. Radially sampled averaged magnetization inversion recovery acquisition (rAMIRA) is a novel approach to perform SC imaging in clinical settings with favorable contrast and is well-suited for SC GM quantitation. However, before applying rAMIRA in clinical studies, it is important to understand (i) the sources of inter-subject variability of total SC cross-sectional areas (TCA) and GM area (GMA) measurements in healthy subjects and (ii) their relation to age and sex to facilitate the detection of pathology-associated changes. In this study, we aimed to develop normalization strategies for rAMIRA-derived SC metrics using skull and spine-based metrics to reduce anatomical variability.Methods: Sixty-one healthy subjects (age range 11–93 years, 37.7% women) were investigated with axial two-dimensional rAMIRA imaging at 3T MRI. Cervical and thoracic levels including the level of the cervical (C4/C5) and lumbar enlargements (Tmax) were examined. SC T2-weighted sagittal images and high-resolution 3D whole-brain T1-weighted images were acquired. TCA and GMAs were quantified. Anatomical variables with associations of |r| > 0.30 in univariate association with SC areas, and age and sex were used to construct normalization models using backward selection with TCAC4/C5 as outcome. The effect of the normalization was assessed by % relative standard deviation (RSD) reductions.Results: Mean inter-individual variability and the SD of the SC area metrics were considerable: TCAC4/5: 8.1%/9.0; TCATmax: 8.9%/6.5; GMAC4/C5: 8.6%/2.2; GMATmax: 12.2%/3.8. Normalization based on sex, brain WM volume, and spinal canal area resulted in RSD reductions of 23.7% for TCAs and 12.0% for GM areas at C4/C5. Normalizations based on the area of spinal canal alone resulted in RSD reductions of 10.2% for TCAs and 9.6% for GM areas at C4/C5, respectively.Discussion: Anatomic inter-individual variability of SC areas is substantial. This study identified effective normalization models for inter-subject variability reduction in TCA and SC GMA in healthy subjects based on rAMIRA imaging.

Anatomical variability of the lateral frontal lobe surface: implication for intersubject variability in language neuroimaging

Relative Strength of Tailor’s Bunion Osteotomies and Fixation Techniques

Bronchodilatory effects of NVA237, a once daily long-acting muscarinic antagonist, in COPD patients

To assess how anatomy and osteogenesis correlated with results of maxillary sinus floor augmentation (MSFA). Patients with partial edentulism and advanced atrophy of the posterior maxillae (≤ 4 mm residual bone height, RBH) underwent MSFA with sole deproteinized bovine bone matrix (DBBM) through a lateral approach. After a 6 to 9-month healing period, bone core biopsies were obtained from the sites of implant insertion for histological evaluation. The correlations between anatomical and histomorphometric variables were analyzed in a multiple regression model. Forty-nine patients were recruited. One biopsy per patient was obtained from the augmented sinus. Thirty-seven bone core biopsies were intact and met the requirement for histomorphometry analysis. The mean (± standard deviation) percentages of vital bone (VB), remaining DBBM, and non-mineralized tissue were 18.25 ± 4.76%, 27.74 ± 6.68%, and 54.08 ± 6.07%, respectively. No statistically significant correlations were found between RBH and VB% (p = 0.44) or between sinus contour and VB% (p = 0.33). However, there was an inverse correlation between the sinus width (SW) and VB % (SW1: R2 = 0.13, p = 0.03; SW2: R2 = 0.15, p = 0.02). After a healing period of 6-9 months, wider sinuses augmented with DBBM alone tended to have a lower proportion of new bone formation, while RBH and sinus contour did not appear to affect osteogenesis after MSFA. This study emphasized the effect of anatomy on osteogenesis after MSFA. The result of the study may have an indication to the clinician that SW is a consideration when selecting the bone grafting material and deciding the healing period of MSFA.

Ectodermal dysplasia (ED) is a congenital syndrome characterized chiefly by abnormalities of tissues of ectodermal origin, namely skin, nails, hair, and teeth. Dental treatment of patients with ED is necessary because it affords the opportunity to develop normal forms of speech, chewing, swallowing, and normal facial support. Because there are few reports focusing on implants inserted in bone grafted in patients with ED, we therefore performed a retrospective study on 44 implants inserted in 4 patients to detect those variables acting on survival and crestal bone remodeling around implant neck in such subjects. Forty-four fixtures were analyzed. Several patient-related (age and sex), anatomic (maxilla and mandible and tooth site), implant (type, length, and diameter), surgical (sites and types of grafts), and prosthetic (type of loading) variables were investigated. Implant failure and peri-implant bone resorption were considered as predictors of clinical outcome. Kaplan-Meier algorithm and Cox regression were then performed to detect those variables statistically associated with the clinical outcome. Implant length and diameter ranged from 11.5 to 15 mm and from 3.5 to 4.0 mm, respectively. Implants were inserted to replace 12 incisors, 12 cuspids, 11 premolars, and 9 molars. No implant was lost. On the contrary, implant's length, grafted sites, and type of loading affected univariate analysis, but these data were not confirmed by multivariate algorithm. Dental implants and bone grafts to orally rehabilitate patients with ED are valuable devices with no difference if compared with unaffected patients, at least in adults.

Purpose: Detecting knee orientation automatically from scout scans with high speed and accuracy is essential to a successful workflow of MR knee imaging. Although traditional methods of image processing such as rigid image registration and object detection are potentially available solutions, they are sensitive to image noise such as missing features due to the metal implants and anatomical variability in knee size and tissue composition. Method: In this study, a segmentation-based approach was proposed to calculate a 3-D transformation matrix that defined 3-D knee orientation using low-res MR scout scans. Specifically, 3-D U-net was used to segment a plane that was parallel to the knee meniscus plane and reconstruct the plane norm as one of the vectors (v1) needed for a 3d transformation matrix. A separate model of 3-D U-net was then trained to segment another plane that was perpendicular to the meniscus and reconstruct the plane norm as v2. A linear 3-D transformation matrix was then obtained for each patient case in 14 testing subjects that were initially manually rotated in small (group S) and large (group L) degrees for training. Angle corrected images were also visually compared against their corresponding ground truth. Results: The average of v1 and v2 error in group S were 5.62° and 5.12° , respectively, whereas the error average of these two vectors were 6.65° and 8.25° , respectively for group L. The standard deviation for v1 and v2 in group S and L were 2.51° , 2.84° , 5.65° , and 7.65° , respectively. The Dice similarity coefficient (DSC) of reconstructed v1 and v2 planes were 0.78, 0.70, 0.71, and 0.65 for group S and L. The qualitative assessment further showed consistent knee representation after correction for knees with heavy distortion and fatty tissue. Conclusion: Initial results suggest that our approach has the potential to automatically correct for small knee rotations commonly seen in clinical setting and is robust even under stress test for knees with anatomical structures (e.g. fatty tissue) that were even absent in the training data set and that appear heavily distorted.

An anatomic variability study of the spatial relationship between the imaged globus pallidus, the optic tract, and the anterior and posterior commissures was performed using T1-weighted gradient echo three-dimensional volume acquisition MRI of 20 patients. Imaging data were resized, reformatted, and manually segmented for the above structures, and mean values and standard deviations for their medial, superior, lateral, and inferior limits determined. Findings demonstrate that the globus pallidus can be consistently and reliably imaged by MRI, that direct stereotactic targeting of this structure can account for normal anatomic variability which may be as much as several millimeters, and that the risk of injury to the optic tract may be reduced with this technique.

Background/IntroductionThe left ventricle is vital for assessing heart function, and its analysis in echocardiographic images supports the diagnosis of many cardiac conditions. However, accurate segmentation is difficult due to image noise, low contrast, and anatomical variability. Using anatomical information and prior shape knowledge can improve the robustness and accuracy of segmentation, especially in challenging cases.PurposeDeep learning techniques are widely used for cardiac segmentation due to their strong performance in image analysis. This work aims to enhance segmentation robustness by integrating prior shape information directly into the network, allowing it to better handle challenging image conditions.MethodThis shape information can be obtained from deep statistical shape models (SSM) that capture the variability of shapes within a population as a statistical representation. We present a fusion-based segmentation approach that combines a state-of-the-art segmentation model with shape information from deep SMM. This shape information is incorporated into the training process through an additional loss term.In our method, we use U-Net for segmentation and employ Base-DeepSSM [2] (Fig. 1_b) and TL-DeepSSM [3] (Fig. 1_c) frameworks to extract shape information in the form of latent codes. These codes are generated using frozen encoders from pre-trained Base/TL-DeepSSM models. The added loss function (L_latent) measures the difference between the latent codes of the predicted segmentations and the original input images (Fig. 1_a). The proposed loss function helps maintain the anatomical shape in the predicted segmentation map. The final loss is the weighted sum of latent loss and dice loss.ResultsWe applied our proposed method to the Echocardiography Analysis (MITEA) dataset [1]. In each image, the endocardium and epicardium of the left ventricle are manually labeled, providing precise anatomical segmentation for training and evaluation. A selected subset of the data was divided into 54 image-label pairs for training (75%), 12 for validation (17%), and 14 for testing (8%). The training runs for a total of 60 epochs: the first 20 epochs train only the U-Net using Dice Loss, and the following 40 epochs include both Dice Loss and the latent loss.The proposed model achieved a highest validation Dice score of 0.84 and reached a Dice of 0.83 on the test dataset for epicardium, with a standard deviation of 0.07. In comparison, the baseline U-Net model obtained a validation Dice score of 0.81 and a test Dice of 0.80, with a higher standard deviation of 0.10. These results indicate that the fusion model offers improved segmentation accuracy and greater consistency over the standard U-Net.A promising direction for future work is to embed shape information directly into the network architecture, such as the U-Net’s encoder, instead of using it solely as an additional loss function.Block diagram of the proposed methodQualitative Results

Experimental study. The goal of this study was to develop a threedimensional (3D)-printed pedicle subtraction osteotomy (PSO) guide plate system. A 3D model and postoperative computed tomography (CT) data were used to evaluate the accuracy of osteotomy with this system. The key to the success of spinal orthopedic treatment is an effectively performed osteotomy. A 3D-printed osteotomy plate can be used for preoperative surgical planning. Due to the anatomical complexity of the spinal region, the clinical application of 3D-printed osteotomy plates remains challenging. The CT scans of 10 patients with thoracolumbar spinal deformities were obtained in the digital imaging and communication in medicine (DICOM) format. The diseased vertebrae and adjacent vertebrae were reconstructed and reduced by computer- aided design software, and an osteotomy plate was designed for the diseased vertebrae. The 3D-printed spinal model and osteotomy plate were used to simulate the operation for PSO. After the operation, the vertebral body treated by osteotomy underwent a CT scan, and the findings were compared with the preoperative design to evaluate the osteotomy accuracy. The new 3D guide plate and spine model were used to successfully simulate 10 cases of PSO, and the comparison of the preoperative and postoperative states indicated that the osteotomy outcomes were excellent. The new 3D-printed PSO guide plate system can be used for preoperative osteotomy planning and demonstrates good accuracy. The results can be used to develop 3D-printed plans for PSO in clinical practice.

These abstracts are presented here as prepared by the authors. The accuracy and content of each abstract remain the responsibility of the authors. In the identification number above each abstract, SPO designates a Sports Physical Therapy Section poster presentation. J Orthop Sports Phys Ther 2014;44(1):A159–A191. doi:10.2519/jospt.2014.44.1.A159

Accurate identification of the hip joint centre (HJC) is crucial for the correct estimation of knee and hip joint loads and kinematics, which is particularly relevant in orthopaedic surgery and musculoskeletal modelling. Several methods have been described for calculation of the HJC in humans, however, no studies have used these methods in the horse despite a similar need for improved evaluation of hip joint biomechanics in rehabilitation and musculoskeletal modelling. This preliminary study uses the commonly used functional method (least-squares sphere fit) to determine the HJC in three equid cadavers. Bone pins with reflective markers attached were drilled into the tuber coxae (TC), tuber ischium (TI), tuber sacrale (TS), greater trochanter (GT), third trochanter (TT) and lateral femoral condyle (FC) of the uppermost limb of the cadavers positioned in lateral recumbency. Three repetitions of passive movements consisting of pro-and retraction, ab- and adduction and circumduction were performed. The HJC was calculated using a least-squares sphere fitting method and presented as a distance from the TC based on a percentage of the TC to TI vector magnitude. Mean (± standard deviation) of the HJC is located 52.4% (± 3.9) caudally, 0.2% (± 6.5) dorsally, and 19.8% (± 4.2) medially from the TC. This study is the first to quantify the HJC in horses ex vivo using a functional method. Further work (in vivo and imaging) is required to validate the findings of the present study.

Achilles tendon loading during weight bearing exercises

Altered patellofemoral joint (PFJ) loading and elevated kinesiophobia are commonly reported in people with patellofemoral pain (PFP). However, the relative relationship of these physical-psychological variables with pain and disability in people with PFP is unknown. To explore the relationship of PFJ loading during stair ascent and kinesiophobia, with self-reported pain and disability in women with PFP. Fifty-seven women with PFP completed the Tampa Scale for Kinesiophobia, a Visual Analog Scale (0-100mm) for pain during stair ascent, and the Anterior Knee Pain Scale (disability). Stair ascent mechanics were assessed via three-dimensional motion analysis while participants ascended an instrumented seven-step staircase. Peak PFJ contact force and stress, and PFJ contact force and stress loading rates were estimated using a musculoskeletal model. The relationships of PFJ kinetics during stair ascent and kinesiophobia, with the Anterior Knee Pain Scale (disability) and pain during stair ascent, were evaluated with Spearman rank correlation. Variables (kinetics and kinesiophobia) significantly correlating with the dependent variables (pain and disability) were inserted in linear regression models. Kinesiophobia was moderately associated with self-reported pain (rho=0.37) and disability (rho=-0.58) in women with PFP. No PFJ loading variables were found to be associated with self-reported pain or disability (P>.05). Kinesiophobia explained 14% of the variance of participants' pain while ascending stairs and 33% of the variance of participant's self-reported disability. Addressing kinesiophobia during treatment of women with PFP may be important to reduce self-reported pain and disability.