Validated finite element analysis of the maverick total disc prosthesis.

Study Design: Combining in vitro tests and finite element analysis to provide a more complete picture of the role that a disc prosthesis implant would play in the biomechanics of the spine.

Objective: Analysis of the disc function after total disc prosthesis insertion with and without antero-posterior or lateral offset and in combination with adjacent fusion.

Summary Of Background Data: To avoid the risk of degenerative cascade the total disc replacement may be considered as an alternative.

Computed tomographic validation of the porcine model for thoracic scoliosis.

Study Design: Computed Tomographic Analysis of the Porcine Scoliosis Model.

Objective: To describe the spinal and rib cage modifications using computed tomography (CT).

Summary Of Background Data: Optimal development of nonfusion techniques for treatment of adolescent idiopathic scoliosis (AIS) requires a reliable large animal model that achieves spinal and rib cage modifications similar to AIS.

Sagittal plane considerations and the pelvis in the adult patient.

Study Design: Research update, focused review.

Objective: Identify the role of the pelvis in the setting of adults with spinal deformity.

Summary Of Background Data: Sagittal plane alignment is increasingly recognized as a critical parameter in the setting of adult spinal deformity.

Pelvic tilt and truncal inclination: two key radiographic parameters in the setting of adults with spinal deformity.

Study Design: Prospective radiographic and clinical analysis.

Objective: Investigate the relationship between spino-pelvic parameters and patient self reported outcomes on adult subjects with spinal deformities.

Summary Of Background Data: It is becoming increasingly recognized that the study of spinal alignment should include pelvic position.

A porcine model for progressive thoracic scoliosis.

Study Design: An IACUC-approved study to create a scoliotic deformity representative of adolescent idiopathic scoliosis.

Objective: The goal of this study was to develop a reliable porcine scoliosis model and to evaluate the three-dimensional progression of the deformity.

Summary Of Background Data: Optimal development of nonfusion techniques for treatment of adolescent idiopathic scoliosis requires a reliable large animal model that achieves a progressive three-dimensional (frontal, sagittal, axial) deformity.

Intraoperative three-dimensional correction during rod rotation technique.

Study Design: A numerical study was conducted by simulating the Cotrel-Dubousset (CD) surgery.

Objective: To quantify intraoperative correction during CD surgery.

Summary Of Background Data: Very few methods have been reported in literature to analyze the effect of intraoperative surgical gestures, and none considers the three-dimensional correction of the entire spine during the main surgical gestures.

Predicting outcome and complications in the surgical treatment of adult scoliosis.

Study Design: prospective, multicenter.

Objective: To determine if models for predicting outcome and complications in the setting of adult deformity surgery can be constructed.

Summary Of Background Data: A classification of adult spinal deformity has been established.

Standing balance and sagittal plane spinal deformity: analysis of spinopelvic and gravity line parameters.

Study Design: Prospective study of 131 patients and volunteers recruited for an analysis of spinal alignment and gravity line (GL) assessment by force plate analysis.

Objective: To determine relationships between GL, foot position, and spinopelvic landmarks in subjects with varying sagittal alignment. Additionally, the study sought to analyze the role of the pelvis in the maintenance of GL position.

Surgical rates and operative outcome analysis in thoracolumbar and lumbar major adult scoliosis: application of the new adult deformity classification.

Study Design: Multicenter prospective consecutive clinical series.

Objective: Investigate the interaction between the Adult Deformity Classification and treatment patterns, surgical strategies, surgery effectiveness, and complication rates.

Summary Of Background Data: An Adult Deformity Classification has been established that applies radiographic parameters of disability.

New interspinous implant evaluation using an in vitro biomechanical study combined with a finite-element analysis.

Study Design: A combined in vitro and finite-element analysis was completed to assess the biomechanical effect of a new interspinous implant on the lumbar spine.

Objective: The aim was to investigate the effect of an interspinous implant on the biomechanical behavior of a vertebral segment.

Methods: An in vitro study on L3-L5 segments from fresh human cadavers was conducted combined with a 3-dimensional finite-element analysis.

Gravity line analysis in adult volunteers: age-related correlation with spinal parameters, pelvic parameters, and foot position.

Study Design: Prospective radiographic and forceplate analysis in adult volunteers.

Objective: Assess gravity line (GL) location and foot position regarding anatomic spinal structures to evaluate key correlations and age-related changes in balance.

Summary Of Background Data: Global spinal balance is commonly assessed by the C7 plumbline.

Total disc arthroplasty: consequences for sagittal balance and lumbar spine movement.

This in vivo biomechanical study was undertaken to analyze the consequences for sagittal balance and lumbar spine movement in three different lumbar disc prostheses. A total of 105 patients underwent total disc replacement in three different centers. The Maverick prosthesis was used in 46 patients, the SB Charité device was used in 49 patients and the Prodisc device was utilized in 10 patients.

Finite element simulation of spinal deformities correction by in situ contouring technique.

Biomechanical models have been proposed in order to simulate the surgical correction of spinal deformities. With these models, different surgical correction techniques have been examined: distraction and rod rotation. The purpose of this study was to simulate another surgical correction technique: the in situ contouring technique.

3D finite element simulation of Cotrel-Dubousset correction.

The Cotrel-Dubousset (CD) scoliosis surgery was simulated for 10 patients with idiopathic scoliosis using a 3D finite element model (FEM) of the patient's entire spine. The geometry of the FEM was extracted from a 3D stereo-radiographic reconstruction, and mechanical properties were personalized using lateral bending films. Finally, each step of the CD correction was simulated and results were compared with the post-operative 3D stereo-radiographic reconstruction.

Finite element simulation of various strategies for CD correction.

The scoliosis surgery using the Cotrel-Dubousset instrumentation is a complex three dimensional correction. This surgery was first simulated for a given patient using a personalized finite element model: the geometry was extracted from a 3D stereoradiographic reconstruction and mechanical properties were personalized using lateral bending tests. Finally, three alternative surgical strategies were simulated in order to analyze their effects on spine postoperative configuration.

Comparison of mechanical behaviour of normal and scoliotic vertebral segment: a preliminary numerical approach.

Specific behaviour of the scoliotic spine has already been proven. The aim of this preliminary study is to evaluate if this behaviour is mainly due to geometrical deformities or to mechanical characteristics of soft tissues. We use a kriging technique to obtain a personalized finite element model of scoliotic spine from 3D reconstructions and from an existing detailed model of normal spine.