Publications by authors named "Wafa Skalli"

Introduction: Although sagittal alignment is known to influence pelvic position, few studies accurately identify the relationship between sagittal alignment and acetabular orientation. We hypothesized that postoperative PT should be correlated with acetabular change in native hips after surgical correction of adult spinal deformity. The objective of this study was therefore to describe the correlation between the change in pelvic tilt and the change in acetabular orientation two years after surgical correction of adult spinal deformity.

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Purpose: The variation of lumbar lordosis between standing and supine position is poorly explored in literature. This study sought to analyze variation of lumbar regional angulations (RA) in healthy volunteers between standing and supine positions, according to pelvic incidence (PI).

Methods: This study included 171 patients who had an abdominal CT-scan in supine position and 879 healthy volunteers with full-body stereoradiographs.

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Accurate estimation of joint load during a lifting/lowering task could provide a better understanding of the pathogenesis and development of musculoskeletal disorders. In particular, the values of the net force and moment at the L5-S1 joint could be an important criterion to identify the unsafe lifting/lowering tasks. In this study, the joint load at L5-S1 was estimated from the motion kinematics acquired using a multi-view markerless motion capture system without force plate.

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Article Synopsis
  • Spinal muscular atrophy (SMA2) is a severe neuromuscular disorder that can lead to spinal deformities like scoliosis, often requiring early surgical intervention when bracing is ineffective.
  • The study investigated changes in spinal and thigh muscles in SMA2 patients before and after a minimally invasive spinal surgery, involving MRI analysis for fat infiltration in muscle tissues.
  • Results showed increased fat infiltration in certain muscles post-surgery, but overall muscle involvement was significant in both preoperative and postoperative groups, while quality of life remained unaffected by these changes.
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Purpose: Our objective was to analysis the barycentremetry, obtained from the external envelope reconstruction of biplanar radiographs, in adolescent idiopathic scoliosis (AIS) and to determine whether assessing would help predict the distinction between progressive and stable AIS at the early stage.

Methods: A retrospective study with a multicentre cohort of 205 AIS was conducted. All AIS underwent a biplanar X-ray between 2013 and 2020.

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Study Design: Retrospective study of a multicentric prospective database.

Objective: This study aimed to determine, in a cohort of healthy volunteers, the impact of sacralized lumbo-sacral transitional vertebra (LSTV) on spinal alignment according to its grade, particularly regarding lumbar lordosis magnitude and distribution, and the implications for spinopelvic parameters measurement.

Summary Of Background Data: There is little data regarding spinopelvic alignment assessment in LSTV patients.

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  • This multicentric retrospective study aimed to establish normative values for proximal junctional angles (PJA) in adult spinal deformity (ASD) surgery patients, using data from healthy volunteers for comparison.
  • The study analyzed data from 721 healthy individuals and 824 ASD surgery patients, assessing the rates of abnormal PJA values and comparing them with the rates of proximal junctional kyphosis (PJK) using different definitions.
  • Findings revealed significant differences in PJK rates based on the criteria used, highlighting the need for more precise level-adjusted assessments of PJA values to better define abnormalities and challenge traditional definitions of PJK.
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Functional assessment is a key element in evaluating adult spinal deformity (ASD) patients. The multitude of 3D kinematic parameters provided by movement analysis can be confusing for spine surgeons. The aim was to investigate movement patterns of ASD based on key kinematic parameters.

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Article Synopsis
  • This study is a retrospective analysis of a database aiming to understand how vertebral bodies and discs contribute to lumbar lordosis, especially as people age and how this is affected by pelvic incidence.
  • 645 healthy volunteers were analyzed to track changes in lumbar lordosis, finding that as age increases, the lordosis from discs decreases while vertebral body kyphosis increases, particularly in older adults.
  • The findings suggest that the vertebral body's importance in lumbar lordosis rises with pelvic incidence and highlights the significance of these changes for surgical planning in the lumbar spine.
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Purpose: The goal of this study was to explore sex-related variations of global alignment parameters and their distinct evolution patterns across age groups.

Methods: This multicentric retrospective study included healthy volunteers with full-body biplanar radiographs in free-standing position. All radiographic data were collected from 3D reconstructions: global and lower limb parameters, pelvic incidence (PI) and sacral slope (SS).

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Study Design: A multicentric retrospective study.

Objective: The study of center of mass (COM) locations (ie, barycentremetry) can help us understand postural alignment. The goal of this study was to determine relationships between COM locations and global postural alignment x-ray parameters in healthy subjects.

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  • This study aimed to evaluate the odontoid-hip axis (OD-HA) angle in patients with mild scoliosis to predict whether adolescent idiopathic scoliosis (AIS) is progressing or stable.
  • Researchers used biplanar X-rays from 2013 to 2020 to analyze the OD-HA angle in 205 AIS patients and 83 non-scoliotic controls, identifying key differences in alignment.
  • The findings indicated that AIS patients are significantly more likely to have malalignment, suggesting the OD-HA measurement could help clinicians assess the stability of scoliosis in adolescents.
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  • The study investigates how spinal surgery for adolescent idiopathic scoliosis (AIS) affects spinal axial torque, which is critical in understanding spinal load distribution.
  • It utilized a retrospective analysis of 29 AIS patients who underwent posterior spinal fusion in 2019, comparing preoperative and postoperative measurements against a reference group of asymptomatic individuals.
  • Findings revealed significant reductions in Cobb angle and spinal axial torque post-surgery, but over 90% of patients still exhibited elevated torque levels, particularly at the upper end vertebra, indicating persistent issues postoperatively.
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Objectives: There are no established criteria for stiffness after fusionless surgery for neuromuscular scoliosis (NMS). As a result, there is no consensus regarding the surgical strategy to propose at long-term follow-up. This study reports the first use of shear wave elastography for assessing the mechanical response of lumbar intervertebral discs (IVDs) after fusionless bipolar fixation (FBF) for NMS and compares them with healthy controls.

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  • Children with X Linked Hypophosphatemia (XLH) experience significant bone issues and may also have distinct muscle characteristics compared to typically developed (TD) children.
  • A study used MRI to analyze muscle morphology in 11 XLH patients and 15 TD children, hypothesizing that XLH would show noticeable differences that could contribute to their limping.
  • Results indicated that most muscle lengths and volumes in XLH patients were smaller than in TD children, with the exception of the medius/minimus gluteus muscles, suggesting a varied muscle structure associated with the condition.
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In vivo characterization of intervertebral disc (IVD) mechanical properties and microstructure could give an insight into the onset and progression of disc pathologies. Ultrasound shearwave elastography provided promising results in children, but feasibility in adult lumbar discs, which are deep in the abdomen, was never proved. The aim of this work was to determine the feasibility and reliability of ultrasound assessment of lumbar IVD in adults.

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Femoro-acetabular impingement (FAI) may present as alterations in the skeletal morphology of the hip. Repercussions of FAI can be witnessed in self-selected speed walking as well as physical exercise such as running or fast speed walking. The aim of this study was to investigate changes in kinematics at different gait speeds in subjects presenting with radiological findings invoking FAI.

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Background: The goal of this study was to better understand the variation of femoral neck version according to spinopelvic and lower limb 3D alignment using biplanar X-rays in standing position.

Methods: This multicentric study retrospectively included healthy subjects from previous studies who had free-standing position biplanar radiographs. Subjects were excluded if they presented spinal or any musculo-skeletal deformity, and reported pain in the spine, hip or knee.

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Objectives: The objectives of this study were to evaluate the repeatability and reproducibility of a method for measuring freehand rod bending and to analyze the relationship between the rod's bend and the resulting sagittal correction.

Materials And Methods: All the children who underwent correction by posterior translation using pedicle screws at all levels were included prospectively in 2018 and 2019. The rod's sagittal parameters were measured retrospectively by three independent surgeons on two separate occasions using the same protocol.

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Introduction: It was hypothesized that pelvic retroversion in Adult Spinal Deformity (ASD) can be related to an increased hip loading explaining the occurrence of hip-spine syndrome.

Research Question: How pelvic retroversion can modify acetabular orientation in ASD during walking?

Methods: 89 primary ASD and 37 controls underwent 3D gait analysis and full-body biplanar X-rays. Classic spinopelvic parameters were calculated from 3D skeletal reconstructions in addition to acetabular anteversion, abduction, tilt, and coverage.

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Background: X-linked hypophosphataemia causes bone deformities and gait abnormalities that tend to worsen with age in the absence of appropriate treatment. However, doctors do not currently use quantitative tools to characterize these symptoms and their possible interactions.

Methods: Radiographs and 3D gait data from 43 non-surgical growing children with X-linked hypophosphataemia were acquired prospectively.

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Introduction: X-linked hypophosphatemic (XLH) rickets causes significant bone deformities in the lower limbs resulting from a bone mineralization defect. According to Frost's Mechanostat theory, compensatory modeling of the bones takes place during increased mechanical loads. In addition, mechanical stimuli modulate the differentiation of mesenchymal stem cells; common precursors to bone marrow adipocytes and osteoblasts.

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The face blurring of images plays a key role in protecting privacy. However, in computer vision, especially for the human pose estimation task, machine-learning models are currently trained, validated, and tested on original datasets without face blurring. Additionally, the accuracy of human pose estimation is of great importance for kinematic analysis.

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Context: Children with X-linked hypophosphatemic (XLH) rickets have muscle weakness that severely impairs their function. Intermuscular and intramuscular adipose tissue (IMAT and intraMAT, respectively) may contribute to this muscle weakness.

Objective: This work aimed to compare IMAT and intraMAT in XLH children vs typically developing (TD) children.

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Adolescent idiopathic scoliosis (AIS) is a three-dimensional deformity of the spine. Spine slenderness, which represents its potential instability to buckling under compressive loads, was shown to be higher in AIS patients than non-scoliotic subjects, but it is not clear at what stage of the progression this difference appeared, nor if slenderness could be used as an early sign of progression. In this study, we hypothesized that slenderness could be an early sign of progression.

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