Biomechanical characteristics of lumbosacral vertebra with unidirectional axial fusion fixation system / 中国组织工程研究

BACKGROUND: It is very important to apply a new technique of minimally invasive, firm fixation and antirotation in the treatment of lumbosacral degenerative diseases. OBJECTIVE: To provide theoretical basis for clinical application by biomechanical study on the treatment of lumbosacral vertebra instability with unidirectional axial fusion internal fixation system. METHODS: Six fresh adult lumbosacral specimens were selected, and the lumbosacral motion segments (L3-S5) were intercepted and divided into the following five groups: The intact normal control group (N group), bilateral isthmus fissure group (UN group), bilateral isthmus fissure + spur axial fusion internal fixation group (A group), bilateral isthmus fissure + axial screw fixation group (B group), bilateral spondylolysis + axial screw fixation alone + pedicle screw fixation on both sides group (C group). The three-dimensional motion range of flexion, lateral bending and rotation of segment L5/S1 in each group of internal fixation was compared with the axial compression resistance. RESULTS AND CONCLUSION: (1) The stability of fixed mode in A, B and C groups was better than that in the N group and the UN group under different directions of motion, and there were statistically significant differences between the groups (P 0.05). (3) In the left and right direction of rotation, the three-dimensional motion range of rotation in the A group was significantly reduced compared with that in the B group, and there was no significant difference between A group and C group (P > 0.05). (4) The lumbosacral vertebra unidirectional axial fusion internal fixation system has good biomechanical stability and strong anti-rotation ability, and is expected to be used in clinic.

Finite element analysis on scoliosis lumbosacral vertebral structure and its deformation trend / 医用生物力学

Objective To study correlation between the deformation and displacement trend of the lumbosacral vertebra (L1-S1) for two typical scoliosis spine under vertical load, so as to provide the mechanical basis of treatment and prevention of scoliosis in clinic. Methods The X-ray computed tomography (CT) imaging of two typical scoliosis spine (Lenke-4AN type and Lenke- 5CN type) were converted into 3D models，and their finite element models were then established and verified. The internal stress distribution and displacement variation of the models were calculated by the finite element software; the correlation between the lumbosacral vertebral structure and displacement of the spine was analyzed. Results Under the same boundary conditions and load cases, the stress and displacement for two kinds of lumbosacral vertebral models showed different trends. Due to its left-leaning and forward convex bending deformation as well as relatively large lordosis angle(60°) and smaller left-leaning angle (17.37°), the Lenke-4AN type lumbosacral spine produced slightly small forward convex displacement(8.18 mm) and relatively large left-leaning displacement (0.97 mm). The Lenke- 5CN type lumbosacral spine showed left-leaning and forward convex bending deformation as well, with relatively large lordosis angle (59°) and left-leaning angle (26.97°), so it produced more severe left-leaning (20.65 mm) and forward deformation (9.22 mm). Conclusions The deformation trend of lumbosacral vertebra is closely related to its structural characteristics, and different scoliosis lumbosacral vertebral structures will cause corresponding deformation trend. The research findings are important for the prevention and treatment of scoliosis.

Finite element analysis on scoliosis lumbosacral vertebral structure and its deformation trend / 医用生物力学

Objective To study the correlation between the deformation and displacement trend of the lumbosacral vertebra (L1-S1) for two typical scoliosis spines under vertical loads,so as to provide the mechanical basis of treatment and prevention of scoliosis in clinic.Methods The X-ray computed tomography (CT) images of two typical scoliosis spines (Lenke-4AN type and Lenke-5CN type) were converted into 3D models,and their finite element models were then established and verified.The internal stress distribution and displacement variation of the models were calculated by the finite element software;the correlation between the lumbosacral vertebral structure and displacement of the spine was analyzed.Results Under the same boundary conditions and load cases,the stress and displacement for two kinds of lumbosacral vertebral models showed different trends.Due to its leftleaning and forward convex bending deformation as well as the relatively large lordosis angle (60°) and smaller left-leaning angle (17.37°),the Lenke-4AN type lumbosacral spine produced slightly small forward convex displacement (8.18 mm) and relatively large left-leaning displacement (0.97 mm).The Lenke-5CN type lumbosacral spine showed left-leaning and forward convex bending deformation as well,with relatively large lordosis angle(59°) and left-leaning angle (26.97°),so it produced more severe left-leaning displacement (20.65 mm) andforward convex displacement (9.22 mm).Conclusions The deformation trend of lumbosacral vertebra is closelyrelated to its structural characteristics,and different scoliosis lumbosacral vertebral structures will cause the corre-sponding deformation trend.The research findings are important for the prevention and treatment of scoliosis.

Finite element analysis on scoliosis lumbosacral vertebral structure and its deformation trend / 医用生物力学

Objective To study the correlation between the deformation and displacement trend of the lumbosacral vertebra (L1-S1) for two typical scoliosis spines under vertical loads,so as to provide the mechanical basis of treatment and prevention of scoliosis in clinic.Methods The X-ray computed tomography (CT) images of two typical scoliosis spines (Lenke-4AN type and Lenke-5CN type) were converted into 3D models,and their finite element models were then established and verified.The internal stress distribution and displacement variation of the models were calculated by the finite element software;the correlation between the lumbosacral vertebral structure and displacement of the spine was analyzed.Results Under the same boundary conditions and load cases,the stress and displacement for two kinds of lumbosacral vertebral models showed different trends.Due to its leftleaning and forward convex bending deformation as well as the relatively large lordosis angle (60°) and smaller left-leaning angle (17.37°),the Lenke-4AN type lumbosacral spine produced slightly small forward convex displacement (8.18 mm) and relatively large left-leaning displacement (0.97 mm).The Lenke-5CN type lumbosacral spine showed left-leaning and forward convex bending deformation as well,with relatively large lordosis angle(59°) and left-leaning angle (26.97°),so it produced more severe left-leaning displacement (20.65 mm) andforward convex displacement (9.22 mm).Conclusions The deformation trend of lumbosacral vertebra is closelyrelated to its structural characteristics,and different scoliosis lumbosacral vertebral structures will cause the corre-sponding deformation trend.The research findings are important for the prevention and treatment of scoliosis.

Finite element analysis on scoliosis lumbosacral vertebral structure and its deformation trend / 医用生物力学

Objective To study the correlation between the deformation and displacement trend of the lumbosacral vertebra (L1-S1) for two typical scoliosis spines under vertical loads,so as to provide the mechanical basis of treatment and prevention of scoliosis in clinic.Methods The X-ray computed tomography (CT) images of two typical scoliosis spines (Lenke-4AN type and Lenke-5CN type) were converted into 3D models,and their finite element models were then established and verified.The internal stress distribution and displacement variation of the models were calculated by the finite element software;the correlation between the lumbosacral vertebral structure and displacement of the spine was analyzed.Results Under the same boundary conditions and load cases,the stress and displacement for two kinds of lumbosacral vertebral models showed different trends.Due to its leftleaning and forward convex bending deformation as well as the relatively large lordosis angle (60°) and smaller left-leaning angle (17.37°),the Lenke-4AN type lumbosacral spine produced slightly small forward convex displacement (8.18 mm) and relatively large left-leaning displacement (0.97 mm).The Lenke-5CN type lumbosacral spine showed left-leaning and forward convex bending deformation as well,with relatively large lordosis angle(59°) and left-leaning angle (26.97°),so it produced more severe left-leaning displacement (20.65 mm) andforward convex displacement (9.22 mm).Conclusions The deformation trend of lumbosacral vertebra is closelyrelated to its structural characteristics,and different scoliosis lumbosacral vertebral structures will cause the corre-sponding deformation trend.The research findings are important for the prevention and treatment of scoliosis.

A Case Report of A Variant of Lumbo-Sacral Transition Vertebrae: Castellvi Type Iia Sacralisation.

Lumbosacral transitional vertebra (LSTV) are congenital anomalies of the lumbosacral spine causing sacralisation or lumbarisation. Sacralisation has been defined as an abnormality where one of the transverse processes of L5 vertebra may articulate or fuse with the sacrum. The sacralisation has been studied for almost a century for its association with low back pain as “Bertolotti Syndrome”, but there are studies for and against its association. Castellvi in 1984 had propounded a radiographical classification identifying sacralisation in four sub types. Out of this, the Type IIA, is the least prevalent wherein there is a unilateral articulation of the L5 transverse process with the sacral ala. Inspite of the controversy, there is a high association of low back pain with disc degeneration, nerve root compression and degenerative facet joints observed with this condition. It is a widely researched vertebral anomaly for its anatomical, developmental and clinical ramifications.

Lumbosacral transitional vertebrae: a case report and clinical implications / Vértebras lumbosacras de transición: reporte de un caso e implicancias clínicas

A lumbosacral transitional vertebra is a rare congenital anomaly which occurs because of defect in the segmentation of the lumbosacral spine during development. During routine osteology classes for the medical students at the Kasturba Medical College, Mangalore, India, one of the sacra showed the fusion of the fifth lumbar vertebra with the sacrum. The specimen showed an incomplete fusion (sacralization) on the left side and the transverse process was of the large butterfly shape, while on the right it was about the usual size. Though this variation is well known, the details of this anomaly are rarely reported in the anatomical literature. Since there is a strong relationship between the lumbosacral transitional vertebrae and low back pain, this anomaly has gotten increased clinical interest. So this case was studied in detail with relevant review of literature and its surgical, radiological implications are discussed.

Una vértebra de transición lumbosacra es una anomalía congénita rara que se produce debido a defectos en la segmentación de la columna lumbosacra durante el desarrollo. Durante una clase de osteología para estudiantes de medicina en Kasturba Medical College, Mangalore, India, una de las regiones sacras mostró fusión de la quinta vértebra lumbar con el sacro. El especimen mostró fusión incompleta (sacralización) en el lado izquierdo y el proceso transverso tenía forma de mariposa grande, mientras que en el derecho se observó de tamaño normal. A pesar que esta variación es conocida, los detalles de esta anomalía rara vez son reportados en la literatura anatómica. Puesto que existe una fuerte relación entre las vértebras de transición lumbosacra y el dolor de espalda baja, esta anomalía tiene gran interés clínico. Este caso fue estudiado en detalle con la revisión pertinente de la literatura, y son discutidas sus implicancias quirúrgicas y radiológicas.