THE IMPACT OF COMBINED FLEXION AND COMPRESSION ON THE MECHANICAL INTEGRITY OF THE ANNULUS FIBROSUS
Notice bibliographique
Résumé
Introduction: Intervertebral disc (IVD) herniation is characterized by an expulsion of nucleus pulposus (NP) material through the annulus fibrosus (AF). The AF contains two major adhesive structures, the intralamellar matrix and the interlamellar matrix, which act to maintain the strength of the AF and prevent NP material migration. As a herniation occurs, clefts form within the intralamellar matrix, pushing the NP between adjacent collagen fibres; meanwhile, delamination of the interlamellar matrix causes the NP to pool between layers of the AF. Further, herniation more readily occurs in a combined loading scenario of both compression and flexion. Flexion, and in particular end range flexion, induces tissue creep, where the elongation of fibres within the AF reduces its capacity for tensile resistance, thereby providing a potential mechanism for why flexion is needed to induce herniation. While previous research has examined the effect of combined flexion and compression on the mechanical properties of the AF, the isolated effect of flexion has not been ascertained.\nAims: The purpose of the current work is to observe the effect of static flexion, in combination with compression, on the intralamellar and interlamellar adhesive properties of the AF.\nMethodology: For this study, the C3/C4 cervical functional spinal units (FSU) of porcine specimens were selected due to their anatomical and biomechanical similarity to human spines. All specimens were loaded under 1200N axial compression and one of the following posture conditions: neutral or static end range flexion for 2-hours. Following loading, six AF samples were dissected from each IVD: four single-layer samples and two multilayer samples. The multi-layer samples underwent peel tests to determine the mechanical properties of the interlamellar matrix while the single-layer samples underwent tensile tests to determine the mechanical properties of the intralamellar matrix. Comparisons between mechanical properties were performed to determine if there was a difference between extraction location (anterior vs posterior), extraction depth (inner vs outer AF) and postural condition. Mechanical properties obtained from these tests were statistically compared across conditions.\nResults: The results demonstrated that flexion had an influence on the mechanical properties of the adhesive matrices of the AF. Regarding the interlamellar matrix, flexion elicited a significant decrease in lamellar adhesive strength when compared to a neutral posture. In consideration to the intralamellar matrix, flexion elicited a decrease in failure point strain when compared to neutral. Furthermore, flexion resulted in a significant increase in stiffness of the inner region of the AF compared to the outer region of the AF in flexion and the inner region of the AF in a neutral posture. Flexion also resulted in a significant decrease in toe region strain for the inner region of the AF when compared to the inner region of the AF in a neutral posture. The inner region of the AF was also seen to have a significant increase in stress at 30% strain when compared to the outer region of the AF when undergoing flexion.\nDiscussion/Conclusion: The current findings suggest that the mechanical properties of the interlamellar and intralamellar matrices are sensitive to flexion, creating an environment that promotes an increased potential for herniations to occur.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,003 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».