Study of mechanical effects of lumbar disc arthroplasty on facet joints at the index level/adjacent levels by using a validated finite element analysis

Introduction: Lumbar disc arthroplasty is a surgical procedure designed to treat degenerative disc disease by replacing the affected disc with a mobile prosthesis. Several types of implants fall under the term total disc replacement, such as balland-socket, mobile core or elastic prostheses. Some studies have shown that facet arthritis can develop after arthroplasty, without much precision on the mechanical impact of the different implant technologies on the facet joints. This study aims to create validated patient-specific finite element models of the intact and post-arthroplasty lumbar spine in order to compare the mechanical response of ball-and-socket and elastic prostheses. Methods: Intact models were developed from CT-scans of human lumbar spine specimens (L4-S1), and arthroplasty models were obtained by replacing the L4-L5 disc with total disc replacement implants. Pure moments were applied to reproduce physiological loadings of flexion/extension, lateral bending and axial rotation. Results: Models with ball-and-socket prosthesis showed increased values in both range of motion and pressure at the index level and lower values at the adjacent level. The mechanical behaviour of the elastic prosthesis and intact models were comparable. The dissipated friction energy in the facet joints followed a similar trend. Conclusion: Although both implants responded to the total disc replacement designation, the mechanical effects in terms of range of motion and facet joint loads varied significantly not only between prostheses but also between specimens. This confirms the interest that patient-specific surgical planning using finite element analysis could have in helping surgeons to choose the appropriate implant for each patient

Study of mechanical effects of lumbar disc arthroplasty on facet joints at the index level/adjacent levels by using a validated finite element analysis

Introduction: Lumbar disc arthroplasty is a surgical procedure designed to treat degenerative disc disease by replacing the affected disc with a mobile prosthesis. Several types of implants fall under the term total disc replacement, such as ball-and-socket, mobile core or elastic prostheses. Some studies have shown that facet arthritis can develop after arthroplasty, without much precision on the mechanical impact of the different implant technologies on the facet joints. This study aims to create validated patient-specific finite element models of the intact and post-arthroplasty lumbar spine in order to compare the mechanical response of ball-and-socket and elastic prostheses.Methods: Intact models were developed from CT-scans of human lumbar spine specimens (L4-S1), and arthroplasty models were obtained by replacing the L4-L5 disc with total disc replacement implants. Pure moments were applied to reproduce physiological loadings of flexion/extension, lateral bending and axial rotation.Results: Models with ball-and-socket prosthesis showed increased values in both range of motion and pressure at the index level and lower values at the adjacent level. The mechanical behaviour of the elastic prosthesis and intact models were comparable. The dissipated friction energy in the facet joints followed a similar trend.Conclusion: Although both implants responded to the total disc replacement designation, the mechanical effects in terms of range of motion and facet joint loads varied significantly not only between prostheses but also between specimens. This confirms the interest that patient-specific surgical planning using finite element analysis could have in helping surgeons to choose the appropriate implant for each patient

Felix von Trojan, Handlung sty ρ en im Epos. Die Homerische Ilias

Severyns Albert. Felix von Trojan, Handlung sty ρ en im Epos. Die Homerische Ilias. In: Revue belge de philologie et d'histoire, tome 8, fasc. 3, 1929. pp. 879-880

Bruno Snell, Lexikon des frühgriechischen Epos (Verantworlicher Redaktor : Hans Joachim Mette). 1. Lieferung : α-ἀεικής

Severyns Albert. Bruno Snell, Lexikon des frühgriechischen Epos (Verantworlicher Redaktor : Hans Joachim Mette). 1. Lieferung : α-ἀεικής. In: L'antiquité classique, Tome 24, fasc. 2, 1955. pp. 510-514

Gabriel Germain, Homère

Severyns Albert. Gabriel Germain, Homère. In: L'antiquité classique, Tome 28, fasc. 2, 1959. pp. 331-333

Homère. Iliade. Texte établi et traduit par Paul Mazon, avec la collaboration de Pierre Chantraine, Paul Collart et René Langumier. Tome I : chants I-VI ; tome II, chants VII-XII. (Collection des Universités de France publiée sous le patronage de V Association Guillaume Budé)

Severyns Albert. Homère. Iliade. Texte établi et traduit par Paul Mazon, avec la collaboration de Pierre Chantraine, Paul Collart et René Langumier. Tome I : chants I-VI ; tome II, chants VII-XII. (Collection des Universités de France publiée sous le patronage de V Association Guillaume Budé). In: L'antiquité classique, Tome 6, fasc. 2, 1937. pp. 413-417

L'épopée grecque

Severyns Albert. L'épopée grecque. In: L'antiquité classique, Tome 1, fasc. 1-2, 1932. pp. 313-344

Gabriel Germain, Genèse de l'Odyssée. Le fantastique et le sacré ; Id., Homère et la mystique des nombres

Severyns Albert. Gabriel Germain, Genèse de l'Odyssée. Le fantastique et le sacré ; Id., Homère et la mystique des nombres. In: L'antiquité classique, Tome 24, fasc. 1, 1955. pp. 168-173

Robert Flacelière. Plutarque. Sur les oracles de la Pythie. Texte et traduction avec une introduction et des notes. (Annales de l'Université de Lyon. Troisième série. Fasc. 4)

Severyns Albert. Robert Flacelière. Plutarque. Sur les oracles de la Pythie. Texte et traduction avec une introduction et des notes. (Annales de l'Université de Lyon. Troisième série. Fasc. 4). In: L'antiquité classique, Tome 6, fasc. 2, 1937. pp. 422-424

En confrontant deux apparats critiques

En comparant les deux apparats critiques de la Vita Homeri de Proclos publiés en 1912 par Allen et en 1916 par Wilamowitz, on constate d'abord que le premier est rempli de fautes positives ou négatives, ensuite que le deuxième est un abrégé du premier, erreurs comprises ; et enfin, que Wilamowitz ajoute de nouvelles inexactitudes parce que son apparat, inspiré d'Allen, se trouve au bas d'un texte recopié non pas d'après Allen, mais d'après Westphal (1866).Severyns Albert. En confrontant deux apparats critiques. In: L'antiquité classique, Tome 26, fasc. 1, 1957. pp. 5-11