SAM

Full-body Postural Alignment Analysis Through Barycentremetry

KHALIFE, Marc — Mon, 01 Apr 2024 00:00:00 GMT

Full-body Postural Alignment Analysis Through Barycentremetry KHALIFE, Marc; VERGARI, Claudio; ASSI, Ayman; GUIGUI, Pierre; ATTALI, Valerie; VALENTIN, Rémi; VAFADAR, Saman; FERRERO, Emmanuelle; SKALLI, Wafa Study design: Multicentric retrospective. Objective: The study of center of mass (COM) locations (i.e. barycentremetry) can help us understand postural alignment. This study goal was to determine relationships between COM locations and global postural alignment X-ray parameters in healthy subjects. The second objective was to determine the impact on spinopelvic alignment of increased distance between anterior body envelope and spine at lumbar apex level. Summary of background data: Unexplored relationship between COM location and spinopelvic parameters. Methods: This study included healthy volunteers with full-body biplanar radiograph including body envelope reconstruction, allowing the estimation of COM location. The following parameters were analyzed: lumbar lordosis (LL), thoracic kyphosis (TK), cervical lordosis (CL), pelvic tilt (PT), Sacro-femoral angle (SFA), Knee flexion angle (KFA), sagittal odontoid-hip axis angle (ODHA). The following COM in the sagittal plane were located: whole body, at thoracolumbar inflexion point, and body segment above TK apex. The body envelope reconstruction also provided the distance between anterior skin and the LL apex vertebral body center (“SV-L distance”). Results: This study included 124 volunteers, with a mean age of 44±19.3. Multivariate analysis confirmed posterior translation of COM above TK apex with increasing LL (P=0.002) through its proximal component, and posterior shift of COM at inflexion point with increasing TK (P=0.008). Increased SV-L distance was associated with greater ODHA (r=0.4) and more anterior body COM (r=0.8), caused by increased TK (r=0.2) and decreased proximal and distal LL (both r=0.3), resulting in an augmentation in SFA (r=0.3) (all P<0.01). Conclusions: Barycentremetry showed that greater LL was associated with posterior shift of COM above thoracic apex while greater TK was correlated with more posterior COM at inflexion point. Whole-body COM was strongly correlated with ODHA. This study also exhibited significant alignment disruption associated with increased abdominal volume, with compensatory hip extension. Level of evidence: II

Redefining physiological whole-body alignment according to pelvic incidence: normative values and prediction models

KHALIFÉ, Marc — Tue, 01 Apr 2025 00:00:00 GMT

Redefining physiological whole-body alignment according to pelvic incidence: normative values and prediction models KHALIFÉ, Marc; SKALLI, Wafa; VERGARI, Claudio; GUIGUI, Pierre; VALENTIN, Rémi; ATTALI, Valerie; GILLE, Olivier; LAFAGE, Virginie; KIM, Han Jo; ASSI, Ayman; FERRERO, Emmanuelle Background context Spinopelvic alignment assessment needs to account for pelvic incidence (PI). Purpose This study aimed at providing normative values for commonly used parameters in whole-body alignment analysis based on PI. Design Multicentric prospective study. Patient sample This study included healthy volunteers with full-body biplanar radiograph in free-standing position. Outcome measures All radiographic data were collected from 3D reconstructions: Sagittal vertical axis (SVA), T1 pelvic angle (TPA), spino-sacral angle (SSA), sagittal odontoid-hip axis angle (ODHA), pelvic parameters, sacro-femoral angle (SFA), knee flexion angle (KFA), ankle flexion angle (AA), Pelvic shift (PSh), lumbar lordosis (LL), thoracic kyphosis (TK) and cervical lordosis (CL). Methods Population was divided into five groups according to PI. Normative values were described for each group. Linear regressions including age and PI provided prediction formulas for PT, TPA, SSA and SFA. Results 642 subjects were included. Mean age was 37.7 ± 16.3 years (range: 18–90). Mean PI in the cohort was 49.3 ± 9.5°. LL, PT, SFA, SSA and TPA correlated with PI and age. ODHA, TK, CL and the other lower limb parameters were not associated with PI. All normative values across PI groups are provided for segmental, regional and global alignment parameters. Prediction formulas were: PT=-12.7 + 0.38*PI + 0.14*Age, TPA=-16.9 + 0.34*PI + 0.15*Age, SSA = 109.8 + 0.58*PI-0.19*Age, and SFA = 173 + 0.39*PI + 0.11*Age. Conclusions SSA, PT, TPA and SFA must be assessed according to patient’s PI. This study provides normative values for each PI group, and predictive formulas taking age and PI into account. PI cannot be used to define thoracic and cervical curvatures.

Functional analysis of the human rib cage over the vital capacity range in standing position using biplanar X-ray imaging

VERGARI, Claudio — Sat, 01 Jan 2022 00:00:00 GMT

Functional analysis of the human rib cage over the vital capacity range in standing position using biplanar X-ray imaging VERGARI, Claudio; SKALLI, Wafa; CLAVEL, Louis; DEMUYNCK, Michel; VALENTIN, Rémi; SANDOZ, Baptiste; SIMILOWSKI, Thomas; ATTALI, Valérie Pathologies of the respiratory system can by accompanied by alterations of the biomechanical function of the rib cage, as well as of its morphology and movement. The assessment of such pathologies could benefit from rib cage kinematic analysis during breathing, but this analysis is challenging because of the difficulties in observing and quantifying bone movements in vivo. This work explored the feasibility of using biplanar x-rays to study rib cage modifications at different lung volumes and evaluated the potential of the method to characterize rib cage kinematic patterns in patients. Forty-seven asymptomatic adults and eleven obstructive sleep apnea syndrome (OSAS) patients underwent biplanar x-rays at three lung volumes: normal breathing, maximal and minimal volume. Rib cage and spinopelvic positional parameters were computed from 3D reconstruction of the skeleton. Results showed that inspiration mostly mobilized the ribs and costo-vertebral junction, while expiration was driven by the spine. OSAS patients had a different sagittal profile at rest than asymptomatic subjects, but these differences decreased at maximal and minimal volume. This suggests that patients employed different biomechanical strategies to attain a trunk configuration similar to asymptomatic subjects at minimal and maximal lung volume. This study confirmed that the proposed method could have an impact for the clinical assessment and understanding of pathologies involving breathing function, and which directly affect rib cage morphology.

Sex-dependent evolution of whole-body postural alignment with age

KHALIFE, Marc — Sat, 01 Jun 2024 00:00:00 GMT

Sex-dependent evolution of whole-body postural alignment with age KHALIFE, Marc; SKALLI, Wafa; ASSI, Ayman; GUIGUI, Pierre; ATTALI, Valerie; VALENTIN, Rémi; GILLE, Olivier; LAFAGE, Virginie; KIM, Han-Jo; FERRERO, Emmanuelle; VERGARI, Claudio 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). Lumbar lordosis (LL), thoracic kyphosis (TK) and cervical lordosis (CL) were also assessed as well as the lumbar and thoracic apex, and thoracolumbar inflexion point. The population was divided into five 5 age groups: Children, Adolescents, Young, Middle-Aged and Seniors. Results This study included 861 subjects (53% females) with a mean age of 34 ± 17 years. Mean PI was 49.6 ± 11.1 and mean LL was − 57.1 ± 11.6°. Females demonstrated a PI increase between Young and Middle-Aged groups (49 ± 11° vs. 55 ± 12°, p < 0.001) while it remained stable in males. SS and LL increased with age in females while remaining constant in males between Children and Middle-aged and then significantly decreased for both sexes between Middle-Aged and Seniors. On average, lumbar apex, inflexion point, and thoracic apex were located one vertebra higher in females (p < 0.001). After skeletal maturity, males had greater TK than females (64 ± 11° vs. 60 ± 12°, p = 0.04), with significantly larger CL (-13 ± 10° vs. -8 ± 10°, p = 0.03). All global spinal parameters indicated more anterior alignment in males. Conclusion Males present more anteriorly tilted spine with age mainly explained by a PI increase in females between Young and Middle-Aged, which may be attributed to childbirth. Consequently, SS and LL increased before decreasing at senior age.

Neurophysiological basis of respiratory discomfort improvement by mandibular advancement in awake OSA patients

VALENTIN, Rémi — Thu, 01 Feb 2024 00:00:00 GMT

Neurophysiological basis of respiratory discomfort improvement by mandibular advancement in awake OSA patients VALENTIN, Rémi; NIÉRAT, Marie‐Cécile; WATTIEZ, Nicolas; JACQ, Olivier; DECAVÈLE, Maxens; ARNULF, Isabelle; SIMILOWSKI, Thomas; ATTALI, Valérie Patients with obstructive sleep apneas (OSA) do not complain from dyspnea during resting breathing. Placement of a mandibular advancement device (MAD) can lead to a sense of improved respiratory comfort (“pseudo‐relief”) ascribed to a habituation phenomenon. To substantiate this conjecture, we hypothesized that, in non‐dyspneic awake OSA patients, respiratory‐related electroencephalographic figures, abnormally present during awake resting breathing, would disappear or change in parallel with MAD‐associated pseudo‐relief. In 20 patients, we compared natural breathing and breathing with MAD on: breathing discomfort (transitional visual analog scale, VAS‐2); upper airway mechanics, assessed in terms of pressure peak/time to peak (TTP) ratio respiratory‐related electroencephalography (EEG) signatures, including slow event‐related preinspiratory potentials; and a between‐state discrimination based on continuous connectivity evaluation. MAD improved breathing and upper airway mechanics. The 8 patients in whom the EEG between‐state discrimination was considered effective exhibited higher Peak/TTP improvement and transitional VAS ratings while wearing MAD than the 12 patients where it was not. These results support the notion of habituation to abnormal respiratory‐related afferents in OSA patients and fuel the causative nature of the relationship between dyspnea, respiratory‐related motor cortical activity and impaired upper airway mechanics in this setting.

Effects of Posture on the Inspiratory and Expiratory Components of Vital Capacity in Healthy Humans

ATTALI, Valerie — Tue, 01 Oct 2024 00:00:00 GMT

Effects of Posture on the Inspiratory and Expiratory Components of Vital Capacity in Healthy Humans ATTALI, Valerie; LAVENEZIANA, Pierantonio; VALENTIN, Rémi; SANDOZ, Baptiste; STRAUS, Christian; SIMILOWSKI, Thomas Comparing sitting and supine vital capacity (VC) helps identifying diaphragm dysfunction.