Publications by authors named "Ayman Assi"

39 Publications

Reliability assessment of cervical spine parameters measured on full-body radiographs in asymptomatic subjects and patients with spinal deformity.

Orthop Traumatol Surg Res 2021 Jul 27:103026. Epub 2021 Jul 27.

Laboratory of Biomechanics and Medical Imaging, Faculty of Medicine, University of Saint-Joseph, Damascus Street, Beirut, Lebanon. Electronic address:

Background: Cervical spinal alignment is usually assessed on full-body radiographs allowing for the concomitant evaluation of possible compensatory mechanisms that may occur at any level in the setting of postural malalignment.

Hypothesis: Cervical parameters measured on full-body radiographs are reliable.

Patients And Methods: A total of 70 subjects were included and divided in 3 groups: asymptomatic adults (n=21), adolescents with idiopathic scoliosis (n=20), and adults with spinal deformity (n=29), for whom full-body low-dose biplanar radiographs were obtained. Eighteen cervical parameters including gaze and cervical curvature, upper cervical spine, global cervical alignment, thoraco-cervical and cervico-pelvic parameters were measured by 4 operators, three times each. The intraclass correlation coefficient (ICC) and the 95% confidence interval (95% CI) where calculated for each parameter and compared between the 3 groups.

Results: ICC and the 95% CI were similar between the 3 groups. The measured parameters showed a very high repeatability (ICC>0.8) except for C0-C2, which presented an average repeatability (ICC=0.57). The cSVA, CTPA, C2-SPi, cranial offset, T1-SPi, CBVA and cranial tilt had a 95% CI<2 (° or cm). The TIA, T1-CL and C0-C2 had a 95% CI>6°.

Discussion: The poor visibility of the foramen magnum, hard palate, C7, T1, and the sternum on radiographs could explain why certain parameters showed a higher measurement error. The assessment of these error margins is essential for an accurate evaluation of cervical spinal deformities and a proper therapeutic approach.

Level Of Evidence: III; retrospective analysis of prospectively collected data.
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http://dx.doi.org/10.1016/j.otsr.2021.103026DOI Listing
July 2021

Balance, barycentremetry and external shape analysis in idiopathic scoliosis: What can the physician expect from it?

Med Eng Phys 2021 Aug 15;94:33-40. Epub 2021 Jun 15.

Arts et Métiers Institute of Technology, Université Sorbonne Paris Nord, IBHGC - Institut de Biomécanique Humaine Georges Charpak, HESAM Université, Paris 75013, France.

Objective: Our objective was to establish a corridor of normality for the external shape 3D parameters and then to assess these variables in adolescent idiopathic scoliosis (AIS).

Methods: Adolescent with mild and severe AIS were included prospectively, as well as a control group of asymptomatic subjects. A quasi-automatic 3D reconstruction of the spine and manual 3D reconstruction of the external envelope was performed from biplanar radiography. The center of mass position, the axial intersegmental moment resulting at the apex and junctional vertebrae, and the coronal trunk balance were automatically computed. A normality corridor of asymptomatic subjects was calculated as the range [5-95 percentiles] for external shape parameters at each vertebral level.

Results: Forty-one asymptomatic subjects (19 females; 22 males; 21 yo, SD=4) and sixty AIS (56 females; 4 males; 13 years old, SD=1.9; 30 mild and 30 severe; 34 thoracic curves and 26 thoraco-lumbar or lumbar curves) were included. All parameters based on the external shape showed differences between AIS and controls, as well as between mild and severe scoliosis. For instance, the intersegmental moment applied to the upper junctional vertebra was above the 95 percentile of controls in 70% of AIS patient. The percentage of severe patients showing parameters higher than the normality corridor was significantly higher than mild patients (p<0.0001).

Conclusions: The analysis of center of mass, vertebral intersegmental moment and coronal trunk balance parameters appear to be relevant in characterizing the 3D deformity of adolescent idiopathic scoliosis. The upper junctional intersegmental moment seems to be able to distinguish the different stages of curvature severity.
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http://dx.doi.org/10.1016/j.medengphy.2021.06.004DOI Listing
August 2021

Gait kinematic alterations in subjects with adult spinal deformity and their radiological determinants.

Gait Posture 2021 07 4;88:203-209. Epub 2021 Jun 4.

Faculty of Medicine, University of Saint-Joseph in Beirut, Lebanon; Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers ParisTech, Paris, France. Electronic address:

Background: Adults with spinal deformity (ASD) are known to have postural malalignment affecting their quality of life. Classical evaluation and follow-up are usually based on full-body static radiographs and health related quality of life questionnaires. Despite being an essential daily life activity, formal gait assessment lacks in clinical practice.

Research Question: What are the main alterations in gait kinematics of ASD and their radiological determinants?

Methods: 52 ASD and 63 control subjects underwent full-body 3D gait analysis with calculation of joint kinematics and full-body biplanar X-rays with calculation of 3D postural parameters. Kinematics and postural parameters were compared between groups. Determinants of gait alterations among postural radiographic parameters were explored.

Results: ASD had increased sagittal vertical axis (SVA:34 ± 59 vs -5 ± 20 mm), pelvic tilt (PT:19 ± 13 vs 11 ± 6°) and frontal Cobb (25 ± 21 vs 4 ± 6°) compared to controls (all p < 0.001). ASD displayed decrease walking speed (0.9 ± 0.3 vs 1.2 ± 0.2 m/s), step length (0.58 ± 0.11 vs 0.64 ± 0.07 m) and increased single support (0.45 ± 0.05 vs 0.42 ± 0.04 s). ASD walked with decreased hip extension in stance (-3 ± 10 vs -7 ± 8°), increased knee flexion at initial contact and in stance (10 ± 11 vs 5 ± 10° and 19 ± 7 vs 16 ± 8° respectively), and decreased knee flexion/extension ROM (55 ± 9 vs 59 ± 7°). ASD had increased trunk flexion (12 ± 12 vs 6 ± 11°) and reduced dynamic lumbar lordosis (-11 ± 12 vs -15 ± 7°, all p < 0.001). Sagittal knee ROM, walking speed and step length were negatively determined by SVA; lack of lumbar lordosis during gait was negatively determined by radiological lumbar lordosis.

Significance: Static compensations in ASD persist during gait, where they exhibit a flexed attitude at the trunk, hips and knees, reduced hip and knee mobility and loss of dynamic lordosis. ASD walked at a slower pace with increased single and double support times that might contribute to their gait stability. These dynamic discrepancies were strongly related to static sagittal malalignment.
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http://dx.doi.org/10.1016/j.gaitpost.2021.06.003DOI Listing
July 2021

Prevalence of STIs, sexual practices and substance use among 2083 sexually active unmarried women in Lebanon.

Sci Rep 2021 May 10;11(1):9855. Epub 2021 May 10.

Marsa Sexual Health Center, Beirut, Lebanon.

Access to sexual and reproductive health in conservative communities and in the MENA region are particularly limited and, as such, increase women's vulnerability to unwanted pregnancies, unsafe abortions, and sexually transmitted infections (STIs). The aim was to assess the prevalence of STIs, sexual practices, recreational drug-use and their possible associations among cisgender unmarried women residing in Lebanon. Data on demographics, sexual practices and substance-use were collected from 2083 unmarried cisgender women who voluntarily attended a sexual health clinic in Lebanon between 2015 and 2019. They tested for HIV, Hepatitis B, Hepatitis C and Syphilis through rapid testing. Other infections (genital warts, Neisseria gonorrhea/Chlamydia trachomatis) were screened for. Regression models were computed between variables. There were two cases of HIV, one of Hepatitis B and syphilis, and no cases of Hepatitis C. Genital warts were present in 15% and symptoms indicative of Neisseria gonorrhea/Chlamydia trachomatis in 14%. Inconsistent condom-use (81%) was significantly associated with number of partners (adj. OR: 0.4). Inconsistent condom-use discussion with partners (33%) was significantly associated with unemployment (adj OR: 1.7), recreational drug-use (adj. OR: 1.4), and number of partners (adj. ORs 3.7-4.4). Unwanted pregnancies (11%) were significantly associated with age (adj. ORs 0.1-0.37), recreational drug-use (adj. OR: 2), using intrauterine device (adj. OR:2.9) and natural birth control methods (adj. OR: 2.4). Recreational drug-use (33%) was significantly associated with age (adj ORs 1.9-2.2), and smoking status (adj. OR: 0.6). The results indicate an urgent need for: (1) Accessible, non-stigmatizing, and inclusive sexual health services dedicated to women's sexual health; (2) Comprehensive and non-stigmatizing sexual health education for all, but especially women, in order to promote safer sexual practices and effective decision making with regards to contraception and condom-use.
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http://dx.doi.org/10.1038/s41598-021-89258-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8110545PMC
May 2021

Eccentric training effects for patients with post-stroke hemiparesis on strength and speed gait: A randomized controlled trial.

NeuroRehabilitation 2021 ;48(4):513-522

Aix Marseille Université, CNRS, Institut des Sciences du Mouvement UMR, Marseille, France.

Background: In hemiparetic patients, the skeletal muscle is mainly affected with a combination of abnormalities (denervation, remodeling, spasticity, and eventually muscular atrophy).

Objective: This study examined the role of eccentric exercise in strengthening muscles of the lower extremity and ultimately improving autonomy in patients with post-stroke hemiparesis during gait.

Methods: Thirty-seven patients hemiparetic adults were recruited, randomized into a control group (n = 19) and an intervention group receiving eccentric muscle strengthening (n = 18). The protocol consisted of three sets of five repetitions of eccentric contraction of the paretic limb after determining the maximum repetition (1 MRI). Evaluation of the 1RM, 10 meters and 6WMT was performed before and after the exercise for each group. Manova test was used to compare the differences between the control and intervention groups.

Results: The paretic limb showed significant increase in one-repetition maximum (1RM) between before and after rehabilitation (p≤0.00003). The two groups of Patients increased their walking speed (p≤0.0005), but we observed a significant difference between groups only for the 6MWT and not on the 10 meters Test.

Conclusions: Eccentric training can be useful in strengthening the muscles of the lower limbs, and promoting gait performance. Eccentric training could complement other methods of managing patients with post-stroke hemiparesis.
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http://dx.doi.org/10.3233/NRE-201601DOI Listing
July 2021

Development and evaluation of a new methodology for Soft Tissue Artifact compensation in the lower limb.

J Biomech 2021 06 18;122:110464. Epub 2021 Apr 18.

Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers Sciences et Technologies, Paris, France.

Skin Marker (SM) based motion capture is the most widespread technique used for motion analysis. Yet, the accuracy is often hindered by Soft Tissue Artifact (STA). This is a major issue in clinical gait analysis where kinematic results are used for decision-making. It also has a considerable influence on the results of rigid body and Finite Element (FE) musculoskeletal models that rely on SM-based kinematics to estimate muscle, contact and ligament forces. Current techniques devised to compensate for STA, in particular multi-body optimization methods, often consider simplified joint models. Although joint personalization with anatomical constraints has improved kinematic estimation, these models yet don't represent a fully reliable solution to the STA problem, thus allowing us to envisage an alternative approach. In this perspective, we propose to develop a conceptual FE-based model of the lower limb for STA compensation and evaluate it for 66 healthy subjects under level walking motor task. Both hip and knee joint kinematics were analyzed, considering both rotational and translational joint motion. Results showed that STA caused underestimation of the hip joint kinematics (up to 2.2°) for all rotational DoF, and overestimation of knee joint kinematics (up to 12°) except in flexion/extension. Joint kinematics, in particular the knee joint, appeared to be sensitive to soft tissue stiffness parameters (rotational and translational mean difference up to 1.5° and 3.4 mm). Analysis of the results using alternative joint representations highlighted the versatility of the proposed modeling approach. This work paves the way for using personalized models to compensate for STA in healthy subjects and different activities.
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http://dx.doi.org/10.1016/j.jbiomech.2021.110464DOI Listing
June 2021

Effect of curve location on the severity index for adolescent idiopathic scoliosis: a longitudinal cohort study.

Eur Radiol 2021 Apr 21. Epub 2021 Apr 21.

Arts et Métiers Institute of Technology, Université Sorbonne Paris Nord, IBHGC - Institut de Biomécanique Humaine Georges Charpak, HESAM Université, 151 bd de l'Hôpital, F-75013, Paris, France.

Objectives: Adolescent idiopathic scoliosis (AIS) is the most common spinal disorder in children. A severity index was recently proposed to identify the stable from the progressive scoliosis at the first standardized biplanar radiographic exam. The aim of this work was to extend the validation of the severity index and to determine if curve location influences its predictive capabilities.

Methods: AIS patients with Cobb angle between 10° and 25°, Risser 0-2, and no previous treatment were included. They underwent standing biplanar radiography and 3D reconstruction of the spine and pelvis, which allowed to calculate their severity index. Patients were grouped by curve location (thoracic, thoracolumbar, lumbar). Patients were followed up until skeletal maturity (Risser ≥ 3) or brace prescription. Their outcome was compared to the prediction made by the severity index.

Results: In total, 205 AIS patients were included; 82% of them (155/189, 95% confidence interval [74-90%]) were correctly classified by the index, while 16 patients were unclassified. Positive predictive ratio was 78% and negative predictive ratio was 86%. Specificity (78%) was not significantly affected by curve location, while patients with thoracic and lumbar curves showed higher sensitivity (≥ 89%) than those with thoracolumbar curves (74%).

Conclusions: In this multicentric cohort of 205 patients, the severity index was used to predict the risk of progression from mild to moderate scoliosis, with similar results of typical major curve types. This index represents a novel tool to aid the clinician and the patient in the modulation of the follow-up and, for progressive patients, their decision for brace treatment.

Key Points: • The severity index of adolescent idiopathic scoliosis has the potential to detect patients with progressive scoliosis as early as the first exam. • Out of 205 patients, 82% were correctly classified as either stable or progressive by the severity index. • The location of the main curve had small effect on the predictive capability of the index.
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http://dx.doi.org/10.1007/s00330-021-07944-4DOI Listing
April 2021

Toward understanding the underlying mechanisms of pelvic tilt reserve in adult spinal deformity: the role of the 3D hip orientation.

Eur Spine J 2021 Sep 27;30(9):2495-2503. Epub 2021 Feb 27.

Laboratory of Biomechanics and Medical Imaging, Faculty of Medicine, University of Saint-Joseph, Beirut, Lebanon.

Purpose: To explore 3D hip orientation in standing position in subjects with adult spinal deformity (ASD) presenting with different levels of compensatory mechanisms.

Methods: Subjects with ASD (n = 159) and controls (n = 68) underwent full-body biplanar X-rays with the calculation of 3D spinopelvic, postural and hip parameters. ASD subjects were grouped as ASD with knee flexion (ASD-KF) if they compensated by flexing their knees (knee flexion ≥ 5°), and ASD with knee extension (ASD-KE) otherwise (knee flexion < 5°). Spinopelvic, postural and hip parameters were compared between the three groups. Univariate and multivariate analyses were then computed between spinopelvic and hip parameters.

Results: ASD-KF had higher SVA (67 ± 66 mm vs. 2 ± 33 mm and 11 ± 21 mm), PT (27 ± 14° vs. 18 ± 9° and 11 ± 7°) and PI-LL mismatch (20 ± 26° vs - 1 ± 18° and - 13 ± 10°) when compared to ASD-KE and controls (all p < 0.05). ASD-KF also had a more tilted (34 ± 11° vs. 28 ± 9° and 26 ± 7°), anteverted (24 ± 6° vs. 20 ± 5° and 18 ± 4°) and abducted (59 ± 6° vs. 57 ± 4° and 56 ± 4°) acetabulum, with a higher posterior coverage (100 ± 6° vs. 97 ± 7° for ASD-KE) when compared to ASD-KE and controls (all p < 0.05). The main determinants of acetabular tilt, acetabular abduction and anterior acetabular coverage were PT, SVA and LL (adjusted R [0.12; 0.5]).

Conclusions: ASD subjects compensating with knee flexion have altered hip orientation, characterized by increased posterior coverage (acetabular anteversion, tilt and posterior coverage) and decreased anterior coverage which can together lead to posterior femoro-acetabular impingement, thus limiting pelvic retroversion. This underlying mechanism could be potentially involved in the hip-spine syndrome.
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http://dx.doi.org/10.1007/s00586-021-06778-4DOI Listing
September 2021

A Novel Classification of 3D Rib Cage Deformity in Subjects With Adolescent Idiopathic Scoliosis.

Clin Spine Surg 2021 Feb 12. Epub 2021 Feb 12.

Faculty of Medicine, University of Saint-Joseph in Beirut, Beirut, Lebanon Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers ParisTech Department of Pediatric Orthopedics, Armand Trousseau Hospital, Université Pierre et Marie Curie-Paris 6, Paris, France.

Study Design: This was a multicentric cross-sectional descriptive study.

Objective: To analyze patterns of 3D rib cage deformity in subjects with adolescent idiopathic scoliosis (AIS) and their relationship with the spinal deformity.

Summary Of Background Data: Subjects with AIS present with rib cage deformity that can affect respiratory functions. The 3D rib cage deformities in AIS and their relationship to the spinal deformity are still unelucidated.

Methods: A total of 200 AIS and 71 controls underwent low-dose biplanar x-rays and had their spine and rib cage reconstructed in 3-dimensional (D). Classic spinopelvic parameters were calculated in 3D and: rib cage gibbosity, thickness, width, volume and volumetric spinal penetration index (VSPI). Subjects with AIS were classified as: group I with mild rib cage deformity (n=88), group II with severe rib cage deformity (n=112) subgrouped into IIa (high gibbosity, n=48), IIb (high VSPI, n=48), and IIc (both high gibbosity and VSPI, n=16).

Results: Groups IIa and IIb had a higher Cobb angle (33 vs. 54 degrees and 46 degrees, respectively) and torsion index (11 vs. 14 degrees and 13 degrees, respectively) than group I. Group IIb showed more severe hypokyphosis (IIb=21 degrees; IIa=33 degrees; I=36 degrees; control=42 degrees) with a reduced rib cage volume (IIb=4731 cm3; IIa=4985 cm3; I=5257 cm3; control=5254 cm3) and thickness (IIb=135 mm; IIa=148 mm; I=144 mm; control=144 mm). Group IIa showed an increasingly large local gibbosity descending from proximal to distal levels and did not follow the axial rotation of the spine. Group IIc showed characteristics of both groups IIa and IIb.

Conclusions: This new classification of 3D rib cage deformity in AIS shows that the management of cases with high VSPI (groups IIb and IIc) should focus on restoring as much kyphosis as possible to avoid respiratory repercussions. Treatment indications in groups I and IIa would follow the consensual basic principles reported in the literature regarding bracing and surgery.
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http://dx.doi.org/10.1097/BSD.0000000000001139DOI Listing
February 2021

How do skeletal and postural parameters contribute to maintain balance during walking?

Hum Mov Sci 2020 Aug 15;72:102658. Epub 2020 Jul 15.

Faculty of Medicine, University of Saint-Joseph in Beirut, Lebanon; Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers ParisTech, Paris, France. Electronic address:

Introduction: Maintaining balance during gait allows subjects to minimize energy expenditure and avoid falls. Gait balance can be measured by assessing the relationship between the center of mass (COM) and center of pressure (COP) during gait. Demographics, skeletal and postural parameters are known to influence gait balance.

Purpose: What are the determinants of dynamic balance during gait in asymptomatic adults among skeletal and demographic parameters?

Methods: 115 adults underwent 3D gait analysis and full-body biplanar X-rays. Angles between the COM-COP line and the vertical were calculated in frontal and sagittal planes during gait: maxima, minima, and ROM were evaluated. Full-body 3D reconstructions were obtained; skeletal and postural parameters of the spine (lumbar lordosis, thoracic kyphosis, sagittal vertical axis SVA), pelvis (pelvic tilt and incidence, acetabular orientation in the 3 planes) and lower limbs (neck shaft angle femoral and tibial torsions) were calculated. A univariate followed by a multivariate analysis were computed between the COM-COP parameters and skeletal and demographic parameters.

Results: The univariate analysis showed that in the frontal plane, maximum (4.6°) of the COM-COP angle was significantly correlated with weight (r = 0.53), age (r = 0.28), height (r = 0.35), SVA (r = 0.23), T1T12 (r = 0.24) and pelvic width (r = 0.25).In the sagittal plane, maximum COM-COP (19.7 ± 2.8°) angle was significantly correlated to acetabular tilt (r = 0.25) and acetabular anteversion (r = 0.21). The multivariate analysis showed that, in the frontal plane, an increase in the maximum of the COM-COP angle was determined by a decreasing height (β = -0.28), an increasing weight (β = 0.48), being a male (β = -0.42), and an increasing posterior acetabular coverage (β = 0.22). In the sagittal plane, an increasing maximum COM-COP angle was determined by a decreasing height (β = -0.38) and an increasing SVA (β = 0.19).

Conclusion: Frontal imbalance appeared to be mainly correlated to demographic parameters. Sagittal imbalance was found to be correlated with weight, height, acetabular parameters and SVA. These results suggest that in addition to demographic parameters, acetabular parameters and SVA are important determinants of balance during gait.
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http://dx.doi.org/10.1016/j.humov.2020.102658DOI Listing
August 2020

Alterations of 3D acetabular and lower limb parameters in adolescent idiopathic scoliosis.

Eur Spine J 2020 08 3;29(8):2010-2017. Epub 2020 Apr 3.

Laboratory of Biomechanics and Medical Imaging, Faculty of Medicine, University of Saint-Joseph in Beirut, Beirut, Lebanon.

Purpose: To evaluate the 3D deformity of the acetabula and lower limbs in subjects with adolescent idiopathic scoliosis (AIS) and their relationship with spino-pelvic alignment.

Methods: Two hundred and seventy-four subjects with AIS (frontal Cobb: 33.5° ± 18° [10°-110°]) and 84 controls were enrolled. All subjects underwent full-body biplanar X-rays with subsequent 3D reconstructions. Classic spino-pelvic and lower limb parameters were collected as well as acetabular parameters: acetabular orientation in the 3 planes (tilt, anteversion and abduction), center-edge angle (CEA) and anterior and posterior sector angles. Subjects with AIS were represented by both lower limb sides and classified by elevated (ES) or lowered (LS), depending on the frontal pelvic obliquity. Parameters were then compared between groups. Determinants of acetabular and lower limb alterations were investigated among spino-pelvic parameters.

Results: Acetabular abduction was higher on the ES in AIS (59.2° ± 6°) when compared to both LS (55.6° ± 6°) and controls (57.5° ± 3.9°, p < 0.001). CEA and acetabular anteversion were higher on the LS in AIS (32° ± 6.1°, 20.5° ± 5.7°) when compared to both ES (28.7° ± 5.1°, 19.8° ± 5.1°) and controls (29.8° ± 4.8°, 19.1° ± 4°, respectively, p < 0.001). Anterior sector angle was lower on both ES and LS in AIS when compared to controls. CEA, acetabular abduction and acetabular anteversion were found to be mostly determined (adjusted R: 0.08-0.32) by pelvic tilt and less by frontal pelvic obliquity, frontal Cobb and T1T12.

Conclusions: Subjects with AIS had a more abducted acetabulum at the lowered side, more anteverted acetabulum and a lack of anterior coverage of both acetabula. These alterations were strongly related to pelvic tilt.
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http://dx.doi.org/10.1007/s00586-020-06397-5DOI Listing
August 2020

Spine slenderness and wedging in adolescent idiopathic scoliosis and in asymptomatic population: an observational retrospective study.

Eur Spine J 2020 04 18;29(4):726-736. Epub 2020 Feb 18.

Laboratory of Biomechanics and Medical Imaging, Faculty of Medicine, University of Saint-Joseph, Beirut, Lebanon.

Purpose: The origin of the deformity due to adolescent idiopathic scoliosis (AIS) is not known, but mechanical instability of the spine could be involved in its progression. Spine slenderness (the ratio of vertebral height to transversal size) could facilitate this instability, thus playing a role in scoliosis progression. The purpose of this work was to investigate slenderness and wedging of vertebrae and intervertebral discs in AIS patients, relative to their curve topology and to the morphology of control subjects.

Methods: A total of 321 AIS patients (272 girls, 14 ± 2 years old, median Risser sign 3, Cobb angle 35° ± 18°) and 83 controls were retrospectively included (56 girls, median Risser 2, 14 ± 3 years). Standing biplanar radiography and 3D reconstruction of the spine were performed. Geometrical features were computed: spinal length, vertebral and disc sizes, slenderness ratio, frontal and sagittal wedging angles. Measurement reproducibility was evaluated.

Results: AIS girls before 11 years of age had slightly longer spines than controls (p = 0.04, Mann-Whitney test). AIS vertebrae were significantly more slender than controls at almost all levels, almost independently of topology. Frontal wedging of apical vertebrae was higher in AIS, as expected, but also lower junctional discs showed higher wedging than controls.

Conclusion: AIS patients showed more slender spines than the asymptomatic population. Analysis of wedging suggests that lower junctional discs and apex vertebra could be locations of mechanical instability. Numerical simulation and longitudinal clinical follow-up of patients could clarify the impact of wedging, slenderness and growth on the biomechanics of scoliosis progression. These slides can be retrieved under Electronic Supplementary Material.
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http://dx.doi.org/10.1007/s00586-020-06340-8DOI Listing
April 2020

What is the most reliable radiographic method to evaluate the longitudinal foot arch? Application in subjects with Adolescent Idiopathic Scoliosis.

Orthop Traumatol Surg Res 2020 11 5;106(7):1263-1268. Epub 2020 Feb 5.

Faculty of Medicine, University of Saint-Joseph in Beirut, Lebanon. Electronic address:

Background: The foot arch is known to be altered in subjects with postural malalignment. Foot arch morphology can be studied simultaneously with body's balance by measuring foot radiographic parameters on full-body biplanar x-rays. There is no consensus on which is the most reliable method to use to draw the foot axes. The aim was to determine the most reliable methods to draw the main foot axes and apply these findings in order to study the difference of foot parameters between AIS and control subjects.

Hypotheses: (1) distant and clear anatomical landmarks are needed to draw the foot axes accurately; (2) foot longitudinal arch parameters differ between AIS and controls.

Methods: Ninety AIS patients and 36 controls have undergone full body biplanar X-rays from which 3D spino-pelvic and postural parameters were collected for each patient. Six radiological foot angles were evaluated on the 2D lateral radiographs: calcaneal pitch (CPA), talar declination (TDA), first metatarsal declination (FMDA), talo-calcaneal (TCA), calcaneal first metatarsal (CFMA) and Meary. Angles were calculated based on three major axes of the foot: talar, calcaneal, and first metatarsal. Two to three methods were used to draw each axis and the reliability of each method was assessed (three operators, 2-times each). Then, differences of the foot parameters between AIS and controls, and determinants of these differences among 3D spino-pelvic and postural parameters were evaluated.

Results: The most reliable methods for drawing the three axes of the foot were those using distant and clear anatomical landmarks on talus, calcaneum and first metatarsal and used for the subsequent analysis. The AIS group showed a significantly lower TDA (22° vs. 24°, p=0.014) and CFMA (141° vs. 144°, p=0.045), and higher FMDA (18° vs. 15°, p=0.008) and Meary's angle (-5° vs. -9°, p=0.005) when compared to controls. Differences were found to be determined mainly by the center of auditory meatus sagittal plumbline.

Discussion: This is the first study to evaluate the most reliable method to draw foot axes on the lateral radiograph of biplanar X-rays in order to assess radiological foot arch parameters. AIS patients were shown to have more elevated foot arch compared to controls.
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http://dx.doi.org/10.1016/j.otsr.2019.11.024DOI Listing
November 2020

Influence of spino-pelvic and postural alignment parameters on gait kinematics.

Gait Posture 2020 02 24;76:318-326. Epub 2019 Dec 24.

Faculty of Medicine, University of Saint-Joseph, Beirut, Lebanon; Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers ParisTech, Paris, France. Electronic address:

Introduction: Postural alignment is altered with spine deformities that might occur with age. Alteration of spino-pelvic and postural alignment parameters are known to affect daily life activities such as gait. It is still unknown how spino-pelvic and postural alignment parameters are related to gait kinematics.

Research Question: To assess the relationships between spino-pelvic/postural alignment parameters and gait kinematics in asymptomatic adults.

Methods: 134 asymptomatic subjects (aged 18-59 years) underwent 3D gait analysis, from which kinematics of the pelvis and lower limbs were extracted in the 3 planes. Subjects then underwent full-body biplanar X-rays, from which skeletal 3D reconstructions and spino-pelvic and postural alignment parameters were obtained such as sagittal vertical axis (SVA), center of auditory meatus to hip axis plumbline (CAM-HA), thoracic kyphosis (TK) and radiologic pelvic tilt (rPT). In order to assess the influence of spino-pelvic and postural alignment parameters on gait kinematics a univariate followed by a multivariate analysis were performed.

Results: SVA was related to knee flexion during loading response (β = 0.268); CAM-HA to ROM pelvic obliquity (β = -0.19); rPT to mean pelvic tilt (β = -0.185) and ROM pelvic obliquity (β = -0.297); TK to ROM hip flexion/extension in stance (β = -0.17), mean foot progression in stance (β = -0.329), walking speed (β = -0.19), foot off (β = 0.223) and step length (β = -0.181).

Significance: This study showed that increasing SVA, CAM-HA, TK and rPT, which is known to occur in adults with spinal deformities, could alter gait kinematics. Increases in these parameters, even in asymptomatic subjects, were related to a retroverted pelvis during gait, a reduced pelvic obliquity and hip flexion/extension mobility, an increased knee flexion during loading response as well as an increase in external foot progression angle. This was associated with a decrease in the walking pace: reduced speed, step length and longer stance phase.
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http://dx.doi.org/10.1016/j.gaitpost.2019.12.029DOI Listing
February 2020

Trunk Growth in Early-Onset Idiopathic Scoliosis Measured With Biplanar Radiography.

Spine Deform 2019 11;7(6):962-970

Department of Pediatric Orthopaedics, Robert Debré Hospital, Paris 7 University, 48 boulevard Sérurier 75019 Paris, France.

Study Design: Cross-sectional and longitudinal retrospective study.

Objectives: To measure thoracic dimensions and volume during growth in early-onset idiopathic scoliosis (EOIS) patients and to compare them to a population of asymptomatic adults and to the previous literature.

Summary Of Background Data: Data on trunk growth for scoliotic children between 6 and 14 years of age is sparse in the literature.

Methods: Thirty-six patients (29 girls and 7 boys, between 3 and 14 years old, average Cobb angle 33°±15°) were included, all with a minimum two-year follow-up. Sixty-one asymptomatic girls and 54 asymptomatic adults were included as control groups. All subjects underwent biplanar radiography and 3D reconstruction of the spine, pelvis, and rib cage. EOIS patients repeated their radiologic examination every six months. Cobb angle, rib cage volume, anteroposterior and transverse diameters, thoracic index, thoracic perimeter, pelvic incidence, and T1-T12 and T1-S1 distance were calculated. Reproducibility of measurement was assessed.

Results: Measurement reliability in such young patients was comparable to previous studies in adolescents and adults. Geometrical parameters of EOIS patients increased linearly with age. For instance, rib cage volume in girls with EOIS increased from 2200 cm at six to seven years of age to 4100 cm at 13-14 years (65% of adult values, 294 cm/y). Comparison with asymptomatic girls showed that EOIS could affect growth spurt. Longitudinal analysis on a cohort of six girls who had a follow-up of six years confirmed the cross-sectional data.

Conclusions: In this longitudinal and cross-sectional study, trunk growth between 3 and 14 years of age was characterized, for the first time, with biplanar radiography and 3D reconstruction. The results can be useful to estimate patient growth and thus have potential application in the surgical planning of EOIS patients.

Level Of Evidence: Level II, retrospective study.
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http://dx.doi.org/10.1016/j.jspd.2019.04.001DOI Listing
November 2019

Are changes in radiological leg alignment and femoral parameters after total hip replacement responsible for joint loading during gait?

BMC Musculoskelet Disord 2019 Nov 10;20(1):526. Epub 2019 Nov 10.

Orthopaedic University Hospital Friedrichsheim gGmbH, Frankfurt/Main, Germany.

Background: Gait kinematics after total hip replacement only partly explain the differences in the joint moments in the frontal plane between hip osteoarthritis patients after hip replacement and healthy controls. The goal of this study was to determine if total hip replacement surgery affects radiological leg alignment (Hip-Knee-Shaft-Angle, femoral offset, Neck-Shaft-Angle and varus/valgus alignment) and which of these parameters can explain the joint moments, additionally to the gait kinematics.

Methods: 22 unilateral hip osteoarthritis patients who were scheduled for total hip replacement were included in the study. Preoperatively and 1 year postoperatively all patients had biplanar radiographic examinations and 3D gait analysis.

Results: The operated leg showed significantly (P < 0.05) more varus (1.1°) as well as a larger femoral offset (+ 8 mm) and a larger Hip-Knee-Shaft-Angle (+ 1.3°) after total hip replacement; however no significant differences in the joint moments in the frontal plane compared to healthy controls were found. The hip moment (first half of stance) and the knee moments (first and second half of stance) were mostly determined by the varus/valgus alignment (29% and respectively 36% and 35%). The combination with a kinematic parameter (knee range of motion, foot progression angle) increased the predictive value for the knee moments.

Conclusion: In our patient group the joint moments after total hip replacement did not differ from healthy controls, whereas radiological leg alignment parameters changed significantly after the total hip replacement. A combination of these radiological leg parameters, especially the varus alignment, and the deviating kinematics explain the joint moments in the frontal plane during gait after total hip replacement surgery. For surgeons it is important not to create too much of a structural varus alignment by implanting the new hip joint as varus alignment can increase the knee adduction moment and the risk for osteoarthritis of the medial knee compartment.

Trial Registration: This study was retrospectively registered with DRKS (German Clinical Trials Register) under the number DRKS00015053. Registered 1st of August 2018.
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http://dx.doi.org/10.1186/s12891-019-2832-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6844039PMC
November 2019

Prevalence of HIV and other sexually transmitted infections and their association with sexual practices and substance use among 2238 MSM in Lebanon.

Sci Rep 2019 10 22;9(1):15142. Epub 2019 Oct 22.

Faculty of Medicine, University of Saint-Joseph in Beirut, Beirut, Lebanon.

UNAIDS report documents 95% increase in new HIV infections among key populations in Eastern Europe and Middle East and North Africa region. Data on HIV and STIs among MSM in Lebanon is still scarce. Therefore, the aim was to assess prevalence of HIV and sexually transmitted infections (STIs) among men who have sex with men (MSM) in Lebanon and associations with sexual practices and substance-use. 2238 MSM attended a sexual health clinic in Lebanon between 2015-2018. Demographics, substance-use and sexual practices were collected. Attendees tested for HIV and other STIs. HIV infection was diagnosed in 5.6% of the sample. Only 19% received sexual health education from reliable sources (school/university/healthcare workers), 78% reported having multiple partners in the past three months (2-5 partners: 58%, 6+: 20%) and 67% reported inconsistent condom-use. Moreover, 40% of HIV + cases were returning attendees who already received information about condom-use. Additionally, having only a school level education (11%) increases the odds of having inconsistent condom-use with casual partners (adj.OR:1.9, p < 0.001). The results reflect the urgent need for: (1) accurate and comprehensive sexual health and harm reduction education and promotion in Lebanon; (2) making pre-exposure prophylaxis available for free to key populations to contain the epidemics at an early stage.
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http://dx.doi.org/10.1038/s41598-019-51688-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6806001PMC
October 2019

Understanding Thoracic Spine Morphology, Shape, and Proportionality.

Spine (Phila Pa 1976) 2020 Feb;45(3):149-157

Spine Research Laboratory, Hospital for Special Surgery, New York, NY.

Study Design: Retrospective review.

Objective: The aim of this study was to describe thoracic kyphosis (TK) in a normal asymptomatic population and to evaluate the association between TK magnitude and its shape.

Summary Of Background Data: Understanding spinal anatomy requires a three-dimensional appreciation of the spine's shape, morphology, and proportions. The customary definition of TK is the angle between T4 and T12. However, little is known on the actual shape of TK in adults.

Methods: Asymptomatic volunteers were recruited; demographic data along with full-body standing radiographs were recorded. Radiographic data such as T1-12 and T4-12 angles were collected. Maximum TK and vertebral orientation/tilt were also collected, in addition to cumulative TK and Centered Kyphosis at T7. The cohort was stratified by T1-12 value (<40°, 40°-60°, and>60°) and comparisons and regressions were performed afterward.

Results: One hundred nineteen subjects were included (average age 50.8 yrs, 81 female). Mean T1-12 kyphosis was 49.5°, mean T4-12 kyphosis 41.5°, and mean maximum TK was 52.6°. T1 was the most anteriorly tilted vertebra, L1 the most posteriorly tilted; T7 was horizontal, independently of T1-12 value or age. Cumulative kyphosis analysis revealed that the apex of kyphosis was located at T6-T7. Regression analysis predicting the value and the percentage of T1-7 both yielded T1-12 as a predictor (Adj. r = 0.32, Adj. r = 0.13).

Conclusion: Changes in kyphosis distribution in an asymptomatic population suggest that TK is not a simple circle arc: with low TK, 2/3 of the kyphosis is located in the upper part and when TK increases, the distribution of kyphosis will be symmetric around T7. It is possible to predict the amount of kyphosis in the upper part using total kyphosis value. This could help estimate preoperative compensation and predict reciprocal change.

Level Of Evidence: 3.
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http://dx.doi.org/10.1097/BRS.0000000000003227DOI Listing
February 2020

Is the apical vertebra the most rotated vertebra in the scoliotic curve?

J Neurosurg Spine 2019 Aug 23:1-7. Epub 2019 Aug 23.

1Faculty of Medicine, University of Saint-Joseph, Beirut, Lebanon; and.

Objective: The aim of this study was to determine if the apical vertebra (AV) in patients with adolescent idiopathic scoliosis (AIS) is the most rotated vertebra in the scoliotic segment.

Methods: A total of 158 patients with AIS (Cobb angle range 20°-101°) underwent biplanar radiography with 3D reconstructions of the spine and calculation of vertebral axial rotations. The type of major curvature was recorded (thoracic, thoracolumbar, or lumbar), and both major and minor curvatures were included. The difference of levels (DL) between the level of maximal vertebral rotation (LMVR) and the AV was calculated as follows: DL = 0 if LMVR and AV were the same, DL = 1 if LMVR was directly above or below the AV, and DL = 2 if LMVR was separated by 1 vertebra or more from the AV. To investigate which factors explained the divergence of the LMVR from the AV, multinomial models were computed.

Results: The distribution of the DL was as follows: for major curvatures, 143 were DL = 0, 11 were DL = 1, and 4 were DL = 2; and for minor curvatures, 53 were DL = 0, 9 were DL = 1, and 31 were DL = 2. The determinants of a DL = 2 (compared with DL = 0) were lumbar curvature (compared with thoracic; adjusted OR 0.094, p = 0.001), major curvature (compared with minor; adjusted OR 0.116, p = 0.001), and curvatures with increasing apical vertebral rotation (adjusted OR 0.788, p < 0.001).

Conclusions: This study showed that the AV is the most rotated vertebra in the majority of major curvatures, while in minor curvatures, the most rotated vertebra appears to be the junctional vertebra between major and minor curvatures in a significant proportion of cases.
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http://dx.doi.org/10.3171/2019.6.SPINE19203DOI Listing
August 2019

Quasi-automatic early detection of progressive idiopathic scoliosis from biplanar radiography: a preliminary validation.

Eur Spine J 2019 Sep 10;28(9):1970-1976. Epub 2019 May 10.

LBM/Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers ParisTech, 151 bd de l'Hôpital, 75013, Paris, France.

Purpose: To validate the predictive power and reliability of a novel quasi-automatic method to calculate the severity index of adolescent idiopathic scoliosis (AIS).

Methods: Fifty-five AIS patients were prospectively included (age 10-15, Cobb 16° ± 4°). Patients underwent low-dose biplanar X-rays, and a novel fast method for 3D reconstruction of the spine was performed. They were followed until skeletal maturity (stable patients) or brace prescription (progressive patients). The severity index was calculated at the first examination, based on 3D parameters of the scoliotic curve, and it was compared with the patient's final outcome (progressive or stable). Three operators have repeated the 3D reconstruction twice for a subset of 30 patients to assess reproducibility (through Cohen's kappa and intra-class correlation coefficient).

Results: Eighty-five percentage of the patients were correctly classified as stable or progressive by the severity index, with a sensitivity of 92% and specificity of 74%. Substantial intra-operator agreement and good inter-operator agreement were observed, with 80% of the progressive patients correctly detected at the first examination. The novel severity index assessment took less than 4 min of operator time.

Conclusions: The fast and semiautomatic method for 3D reconstruction developed in this work allowed for a fast and reliable calculation of the severity index. The method is fast and user friendly. Once extensively validated, this severity index could allow very early initiation of conservative treatment for progressive patients, thus increasing treatment efficacy and therefore reducing the need for corrective surgery. These slides can be retrieved under Electronic Supplementary Material.
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http://dx.doi.org/10.1007/s00586-019-05998-zDOI Listing
September 2019

Alterations of treatment-naïve pelvis and thigh muscle morphology in children with cerebral palsy.

J Biomech 2019 01 27;82:178-185. Epub 2018 Oct 27.

Laboratory of Biomechanics and Medical Imaging, Faculty of Medicine, University of Saint-Joseph in Beirut, Lebanon.

Lower limb (LL) muscle morphology and growth are altered in children with cerebral palsy (CP). Muscle alterations differ with age and with severity of motor impairment, classified according to the gross motor classification system (GMFCS). Muscle alterations differ also with orthopedic intervention, frequently performed at the level of the shank muscles since an early age, such as the gastrocnemius. The aim was to investigate the alterations of treatment-naïve pelvis and thigh muscle lengths and volumes in children with GMFCS levels I and II, of varying ages. 17 children with CP (GMFCS I: N = 9, II: N = 8, age: 11.7 ± 4 years), age-matched to 17 typically developing (TD) children, underwent MRI of the LL. Three-dimensional reconstructions of the muscles were performed bilaterally. Muscle volumes and lengths were calculated in 3D and compared between groups. Linear regression between muscle volumes and age were computed. Adductor-brevis and gracilis lengths, as well as rectus-femoris volume, were decreased in GMFCS I compared to TD (p < 0.05). Almost all the reconstructed muscle volumes and lengths were found to be altered in GMFCS II compared to TD and GMFCS I. All muscle volumes showed significant increase with age in TD and GMFCS I (R range: 0.3-0.9, p < 0.05). Rectus-femoris, hamstrings and adductor-longus showed reduced increase in the muscle volume with age in GMFCS II when compared to TD and GMFCS I. Alterations of treatment-naïve pelvis and thigh muscle volumes and lengths, as well as muscle growth, seem to increase with the severity of motor impairment in ambulant children with CP.
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http://dx.doi.org/10.1016/j.jbiomech.2018.10.022DOI Listing
January 2019

Cervical and postural strategies for maintaining horizontal gaze in asymptomatic adults.

Eur Spine J 2018 11 7;27(11):2700-2709. Epub 2018 Sep 7.

Faculty of Medicine, University of Saint-Joseph, Beirut, Lebanon.

Purpose: To investigate the different cervical strategies for maintaining horizontal gaze in asymptomatic subjects.

Methods: One hundred and forty-four asymptomatic adults filled the SF-36 quality of life questionnaire and underwent full-body biplanar radiographs. Chin brow vertical angle (CBVA) and postural and cervical parameters were measured. Subjects were grouped according to cervical spine curvature (C2-C7 angle): kyphotic (< - 5°), straight [- 5°, 5°], lordotic (> 5°). Demographics, SF-36 component scores and CBVA were compared between groups. All other parameters were compared between groups, while controlling for confounding factors (ANCOVA). A correlation test was conducted between all cervical parameters.

Results: 32% of subjects had kyphotic (- 12° ± 7°), 27% straight (0° ± 3°) and 41% lordotic (12° ± 7°) cervical spines. While demographic and SF-36 data did not differ between groups, CBVA differed between lordotic and kyphotic groups (2° vs. 6.5°, p = 0.002). Sagittal vertical axis (SVA) and thoracic kyphosis (TK) were lower in the kyphotic group (SVA: K = - 26 ± 20 mm vs. L = - 2 ± 21 mm, p < 0.001; TK: K = 40° ± 6° vs. L = 51° ± 8°, p < 0.001). C2 slope (K = 29° ± 6° vs. L = 18° ± 6°, p < 0.001), C0-C2 (K = 42° ± 8° vs. L = 30° ± 8°, p < 0.001) and C1-C2 (K = 33° ± 6° vs. L = 28° ± 6°, p = 0.004) were higher in the kyphotic group. Significant correlations were found between almost all cervical parameters and C2-C7 angle.

Conclusions: Subjects with cervical kyphosis presented with more posterior global alignment and lower TK than subjects with lordosis. In order to maintain horizontal gaze, subjects with cervical kyphosis presented with a more lordotic upper cervical spine than subjects with cervical lordosis. Subjects with straight cervical curvature presented with an intermediate sagittal alignment. These slides can be retrieved under Electronic Supplementary Material.
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http://dx.doi.org/10.1007/s00586-018-5753-3DOI Listing
November 2018

Combining acetabular and femoral morphology improves our understanding of the down syndrome hip.

Clin Biomech (Bristol, Avon) 2018 10 24;58:96-102. Epub 2018 Jul 24.

Laboratory of Biomechanics and Medical Imaging, Faculty of Medicine, University of Saint-Joseph, Beirut, Lebanon; Hôtel-Dieu de France Hospital, University of Saint-Joseph, Beirut, Lebanon.

Background: Hip instability is frequent in patients with Down syndrome. Recent studies have suggested that skeletal hip alterations are responsible for this instability; however, there are currently no studies simultaneously assessing femoral and acetabular anatomy in subjects with Down syndrome in the standing position. The aim was to analyze the three-dimensional anatomy of the Down syndrome hip in standing position.

Methods: Down syndrome subjects were age and sex-matched to asymptomatic controls. All subjects underwent full body biplanar X-rays with three-dimensional reconstructions of their pelvises and lower limbs. Parameter means and distributions were compared between the two groups.

Findings: Forty-one Down syndrome and 41 control subjects were recruited. Acetabular abduction (mean = 52° [SD = 9°] vs. mean = 56° [SD = 8°]) and anteversion (mean = 14° [SD = 8°] vs. mean = 17.5° [SD = 5°]) as well as posterior acetabular sector angle (mean = 91° [SD = 7°] vs. mean = 94° [SD = 7°]) were significantly lower in Down syndrome subjects compared to controls (P < 0.01). Anterior acetabular sector angle (mean = 62° [SD = 10°] vs. mean = 59° [SD = 7°]; P < 0.01) was significantly higher in Down syndrome compared to controls. The distributions of acetabular anteversion (P = 0.002;V = 0.325), femoral anteversion (P = 0.004;V = 0.309) and the instability index (P < 0.001;V = 0.383) were significantly different between the two groups, with subjects with Down syndrome having both increased anteversion and retroversion for each of these parameters.

Interpretation: Subjects with Down syndrome were found to have a significantly altered and more heterogeneous anatomy of their proximal hips compared to controls. This heterogeneity suggests that treatment strategies of hip instability in Down syndrome should be subject-specific and should rely on the understanding of the underlying three-dimensional anatomy of each patient.
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http://dx.doi.org/10.1016/j.clinbiomech.2018.07.016DOI Listing
October 2018

Are the sagittal cervical radiographic modifiers of the Ames-ISSG classification specific to adult cervical deformity?

J Neurosurg Spine 2018 Nov;29(5):483-490

1Faculty of Medicine and.

OBJECTIVEThe Ames-International Spine Study Group (ISSG) classification has recently been proposed as a tool for adult cervical deformity evaluation. This classification includes three radiographic cervical sagittal modifiers that have not been evaluated in asymptomatic adults. The aim of this study was to determine whether the sagittal radiographic modifiers described in the Ames-ISSG cervical classification are encountered in asymptomatic adults without alteration of health-related quality of life (HRQOL).METHODSThe authors conducted a cross-sectional study of subjects with an age ≥ 18 years and no cervical or back-related complaints or history of orthopedic surgery. All subjects underwent full-body biplanar radiographs with the measurement of cervical, segmental, and global alignment and completed the SF-36 HRQOL questionnaire. Subjects were classified according to the sagittal radiographic modifiers (chin-brow vertical angle [CBVA], mismatch between T1 slope and cervical lordosis [TS-CL], and C2-7 sagittal vertical axis [cSVA]) of the Ames-ISSG classification for cervical deformity, which also includes a qualitative descriptor of cervical deformity, the modified Japanese Orthopaedic Association (mJOA) myelopathy score, and the Scoliosis Research Society (SRS)-Schwab classification for spinal deformity assessment. Characteristics of the subjects classified by the different modifier grades were compared.RESULTSOne hundred forty-one asymptomatic subjects (ages 18-59 years, 71 females) were enrolled in the study. Twenty-seven (19.1%) and 61 (43.3%) subjects were classified as grade 1 in terms of the TS-CL and CBVA modifiers, respectively. Ninety-eight (69.5%) and 4 (2.8%) were grade 2 for these same respective modifiers. One hundred thirty-six (96.5%) subjects had at least one modifier at grade 1 or 2. There was a significant relationship between patient age and grades of TS-CL (p < 0.001, Cramer's V [CV] = 0.32) and CBVA (p = 0.04, CV = 0.22) modifiers. The HRQOL, global alignment, and segmental alignment parameters were similar among the subjects with different modifier grades (p > 0.05).CONCLUSIONSThe CBVA and TS-CL radiographic modifiers of the Ames-ISSG classification do not seem to be specific to subjects with cervical deformities and can occur in asymptomatic subjects without alteration in HRQOL.
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http://dx.doi.org/10.3171/2018.2.SPINE171285DOI Listing
November 2018

From Static Spinal Alignment to Dynamic Body Balance: Utilizing Motion Analysis in Spinal Deformity Surgery.

JBJS Rev 2018 Jul;6(7):e3

Department of Orthopaedic Surgery and Rehabilitation Medicine, State University of New York (SUNY) Downstate Medical Center, Brooklyn, New York.

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http://dx.doi.org/10.2106/JBJS.RVW.17.00189DOI Listing
July 2018

What's Important: Foundations of Orthopaedics-The "Multiple-of-Three Rule": Where Is the Evidence?

J Bone Joint Surg Am 2018 Jul;100(13):1165-1166

Faculty of Medicine, Saint-Joseph University, Beirut, Lebanon.

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http://dx.doi.org/10.2106/JBJS.17.01640DOI Listing
July 2018

Spinopelvic Alignment in Subjects With Down Syndrome.

Clin Spine Surg 2018 07;31(6):E322-E328

Laboratory of Biomechanics and Medical Imaging, Faculty of Medicine.

Study Design: This was a cross-sectional study.

Objective: The aim of this study was to describe the spinopelvic alignment of subjects with Down syndrome (DS).

Summary Of Background Data: Subjects with DS are known to suffer from a large prevalence of scoliosis. While scoliosis is known to significantly affect postural alignment, there are currently no studies on the spinopelvic alignment of subjects with DS.

Materials And Methods: In total, 41 subjects (28 female subjects and 13 male subjects) with DS, age and sex-matched to 41 asymptomatic subjects, underwent biplanar x-rays with 3-dimensional reconstructions of their spines and pelvises, followed by measurement of commonly used spinopelvic sagittal and coronal alignment parameters. Subjects were then classified into one of Roussouly's 4 types of sagittal alignment. Alignment parameters and prevalence of alignment patterns were compared between the 2 groups.

Results: Subjects with DS were found to be relatively hypokyphotic (T4-T12=-29.0 vs. -37.5 degrees; P<0.001) and hyperlordotic (L1-L5=53.8 vs. 44.3 degrees; P<0.001) with larger pelvic incidence (53.2 vs. 45.1 degrees; P<0.001), sacral slope (47.7 vs. 36.8 degrees; P<0.001), Cobb angle (10.2 vs. 8.0 degrees; P=0.005), and axial rotation of the apical vertebra (6.6 vs. 3.7 degrees; P<0.001) but had smaller pelvic tilt (4.9 vs. 8.1 degrees; P<0.001) compared with control subjects. Roussouly's type 4 was found to be the most frequent pattern in DS subjects (68.3% vs. 14.6%; P<0.001).

Conclusions: Subjects with DS were found to have a peculiar pattern of hypokyphosis, hyperlordosis, large pelvic incidence, and small pelvic tilt. The altered spinopelvic alignment found in DS could predispose these subjects to hip instability and osteoarthritis.

Level Of Evidence: Level III.
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http://dx.doi.org/10.1097/BSD.0000000000000655DOI Listing
July 2018

A NEW APPROACH IN THE CLINICAL DECISION-MAKING FOR CEREBRAL PALSY USING THREE-DIMENSIONAL SUBJECT-SPECIFIC MUSCULOSKELETAL RECONSTRUCTIONS.

J Med Liban 2016 Jul-Sep;64(3):152-9

Cerebral palsy (CP) is a neurological disorder which can cause muscular spasticity. Children with this condition suffer from a combination of gait deviations, skeletal deformities and muscular abnormalities. Precise evaluation of each of these three components is crucial for management planning in children with CP. The aim of this study is to review the latest innovative methods used for three-dimensional (3D) gait analysis and musculoskeletal modeling in children with cerebral palsy. 3D gait analysis is a quantitative objective method based on the use of infrared cameras. It allows the evaluation of dynamic joint angles, forces and moments applied on joints and is usually coupled with dynamic electromyography. Skeletal evaluation is usually based on two-dimensional X-rays and physical examination in clinical practice. However, a novel method based on stereoradiographic 3D reconstruction of biplanar low dose X-rays allows a more thorough evaluation of skeletal deformities, and in particular torsional anomalies. Muscular evaluation of children with CP is most commonly based on magnetic resonance imaging, whereby delimitation of lower limb muscles on axial slices allows 3D reconstruction of these muscles. Novel innovative techniques allow similar reconstructions by extrapolation, thus limiting the necessary quantity of axial slices that need to be manually delimitated.
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http://dx.doi.org/10.12816/0031524DOI Listing
September 2017

Roussouly's sagittal spino-pelvic morphotypes as determinants of gait in asymptomatic adult subjects.

Gait Posture 2017 05 22;54:27-33. Epub 2017 Feb 22.

Laboratory of Biomechanics and Medical Imaging, Faculty of Medicine, University of Saint-Joseph, Beirut, Lebanon; Hôtel-Dieu de France Hospital, University of Saint-Joseph, Beirut, Lebanon.

Sagittal alignment is known to greatly vary between asymptomatic adult subjects; however, there are no studies on the possible effect of these differences on gait. The aim of this study is to investigate whether asymptomatic adults with different Roussouly sagittal alignment morphotypes walk differently. Ninety-one asymptomatic young adults (46M & 45W), aged 21.6±2.2years underwent 3D gait analysis and full body biplanar X-rays with three-dimensional (3D) reconstructions of their spines and pelvises and generation of sagittal alignment parameters. Subjects were divided according to Roussouly's sagittal alignment classification. Sagittal alignment and kinematic parameters were compared between Roussouly types. 17 subjects were classified as type 2, 47 as type 3, 26 as type 4 but only 1 as type 1. Type 2 subjects had significantly more mean pelvic retroversion (less mean pelvic tilt) during gait compared to type 3 and 4 subjects (type 2: 8.2°; type 3:11.2°, type 4: 11.3°) and significantly larger ROM pelvic obliquity compared to type 4 subjects (type 2: 11.0°; type 4: 9.1°). Type 2 subjects also had significantly larger maximal hip extension during stance compared to subjects of types 3 and 4 (type 2: -11.9°; type 3: -8.8°; type 4: -7.9°) and a larger ROM of ankle plantar/dorsiflexion compared to type 4 subjects (type 2: 31.1°; type 4: 27.9°). Subjects with type 2 sagittal alignment were shown to have a gait pattern involving both increased hip extension and pelvic retroversion which could predispose to posterior femoroacetabular impingement and consequently osteoarthritis.
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http://dx.doi.org/10.1016/j.gaitpost.2017.02.018DOI Listing
May 2017

Three-dimensional kinematics of upper limb anatomical movements in asymptomatic adults: Dominant vs. non-dominant.

Hum Mov Sci 2016 Dec 14;50:10-18. Epub 2016 Sep 14.

Laboratory of Biomechanics and Medical Imaging, Faculty of Medicine, University of Saint-Joseph, Beirut, Lebanon; Hôtel-Dieu de France Hospital, Beirut, Lebanon. Electronic address:

The effect of dominance on upper limb (UL) kinematics has only been studied on scapular movements. Moreover, when an anatomical UL movement is performed in a specific plane, secondary movements in the remaining planes involuntarily occur. These secondary movements have not been previously evaluated. The aim of this study was to compare the kinematics of primary and secondary angles of dominant and non-dominant UL during anatomical movements in asymptomatic adults. 25 asymptomatic adults performed 6 anatomical movements bilaterally: shoulder flexion-extension, abduction-adduction, horizontal abduction-adduction, internal-external rotation, elbow flexion-extension and wrist pronation-supination. Kinematics of the dominant and non-dominant UL were compared by their ranges of motion (ROM) and their angular waveforms (Coefficient of Multiple Correlations, CMC). The comparison between dominant and non-dominant UL kinematics showed different strategies of movement, most notably during elbow flexion-extension (CMC=0.29): the dominant UL exhibited more pronation at maximal elbow flexion. Significant secondary angles were found on most of the UL anatomical movements; e.g. a secondary ROM of shoulder (humero-thoracic) external-internal rotation (69°±16°) was found when the subject intended to perform maximal shoulder abduction-adduction (119°±21°). Bias of dominance should be considered when comparing pathological limb to the controlateral one. Normative values of primary and secondary angles during anatomical movements could be used as a reference for future studies on UL of subjects with neurological or orthopedic pathologies.
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http://dx.doi.org/10.1016/j.humov.2016.09.002DOI Listing
December 2016
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