Does spinopelvic alignment affect fixation stability in pelvic ring fractures?: A finite element study.

Background: The pelvic ring plays a pivotal role in maintaining biomechanical stability during upright posture. While lumbopelvic fixation is effective for stabilizing unstable pelvic fractures, the influence of spinopelvic alignment, particularly sacral slope on fixation mechanics and stress on adjacent joints, has not been adequately investigated.

Methods: A finite element model of the lumbar spine, pelvis, and femur was used to simulate a pelvic ring fracture.

Phase-specific changes in hip joint loading during gait following sacroiliac joint fusion: Findings from a finite element analysis.

Background: Low back pain affects over 80 % of adults, with sacroiliac joint dysfunction accounting for 15-30 % of these cases. Sacroiliac fusion is a surgical procedure for refractory joint pain. While the biomechanics of the joint and its fusion relative to the spinal column are well-known, the hip-spine relationship post-fusion remains unclear.

Effects of pelvic fixation strategies and multi-rod constructs on biomechanics of the proximal junction in long thoracolumbar posterior instrumented fusions: a finite-element analysis.

Purpose: To assess the effect of various pelvic fixation techniques and number of rods on biomechanics of the proximal junction of long thoracolumbar posterior instrumented fusions.

Methods: A validated spinopelvic finite-element (FE) model was instrumented with L5-S1 ALIF and one of the following 9 posterior instrumentation configurations: (A) one traditional iliac screw bilaterally ("2 Iliac/2 Rods"); (B) T10 to S1 ("Sacral Only"); (C) unilateral traditional iliac screw ("1 Iliac/2 Rods"); (D) one traditional iliac screw bilaterally with one midline accessory rod ("2 Iliac/3 rods"); (E) S2AI screws connected directly to the midline rods ("2 S2AI/2 Rods"); and two traditional iliac screws bilaterally with two lateral accessory rods connected to the main rods at varying locations (F1: T10-11, F2: T11-12, F3: T12-L1, F4: L1-2) ("4 Iliac/4 Rods"). Range of motions (ROM) at T10-S1 and T9-T10 were recorded and compared between models.

Evaluating the biomechanical effects of pedicle subtraction osteotomy at different lumbar levels: a finite element investigation.

Background: Pedicle subtraction osteotomy (PSO) is effective for correcting spinal malalignment but is associated with high complication rates. The biomechanical effect of different PSO levels remains unclear, and no finite element (FE) analysis has compared L2-, L3-, L4-, and L5-PSOs.

Purpose: To assess the effects of PSO level on the spine's global range of motion, stresses on posterior instrumentation, load sharing with the anterior column, and proximal junctional stresses.

Biomechanical Effects of Thoracic Flexibility and Stiffness on Lumbar Spine Loading: A Finite Element Analysis Study.

Objective: To determine the effects of thoracic stiffness on mechanical stress in the lumbar spine during motion.

Methods: To evaluate the effect of preoperative thoracic flexibility, stiff and flexible spine models were created by changing the material properties of ligaments and discs in the thoracic spine. Total laminectomy was performed at L4/5 in stiff and flexible models.

Biomechanical evaluation of multi-rod constructs to stabilize an S1 pedicle subtraction osteotomy (PSO): a finite element analysis.

Purpose: To develop and validate a finite element (FE) model of a sacral pedicle subtraction osteotomy (S1-PSO) and to compare biomechanical properties of various multi-rod configurations to stabilize S1-PSOs.

Methods: A previously validated FE spinopelvic model was used to develop a 30° PSO at the sacrum. Five multi-rod techniques spanning the S1-PSO were made using 4 iliac screws and a variety of primary rods (PR) and accessory rods (AR; lateral: Lat-AR or medial: Med-AR).

The Effect of Posterior Lumbar Interbody Fusion in Lumbar Spine Stenosis with Diffuse Idiopathic Skeletal Hyperostosis: A Finite Element Analysis.

Objective: Lumbar spinal canal stenosis (LSS) with diffuse idiopathic skeletal hyperostosis (DISH) can require revision surgery because of the intervertebral instability after decompression. However, there is a lack of mechanical analyses for decompression procedures for LSS with DISH.

Methods: This study used a validated, three-dimensional finite element model of an L1-L5 lumbar spine, L1-L4 DISH, pelvis, and femurs to compare the biomechanical parameters (range of motion [ROM], intervertebral disc, hip joint, and instrumentation stresses) with an L5-sacrum (L5-S) and L4-S posterior lumbar interbody fusion (PLIF).

Effects of Sacral Slope Changes on the Intervertebral Disc and Hip Joint: A Finite Element Analysis.

Objective: Spinopelvic parameters are vital components that must be considered when treating patients with spinal disease. Several finite element (FE) studies have explored spinopelvic parameters such as sacral slope (SS) and the impact on the lumbar spine, although no study has examined the effect on the hip and sacroiliac joint (SIJ) on varying SS angles. Therefore, it is necessary to have a biomechanical understanding of the impact on the spinopelvic complex.

The Effect of Anterior-Only, Posterior-Only, and Combined Anterior Posterior Fixation for Cervical Spine Injury with Soft Tissue Injury: A Finite Element Analysis.

Objective: This finite element analysis aimed to investigate the effects of surgical procedures for cervical spine injury.

Methods: A three-dimensional finite element model of the cervical spine (C2-C7) was created from computed tomography. This model contained vertebrae, intervertebral discs, anterior longitudinal ligament, and posterior ligament complex.

Total disc replacement alters the biomechanics of cervical spine based on sagittal cervical alignment: A finite element study.

Introduction: The correlation between cervical alignment and clinical outcome of total disc replacement (TDR) surgery is arguable. We believe that this conflict exists because the parameters that influence the biomechanics of the cervical spine are not well understood, specifically the effect of TDR on different cervical alignments.

Methods: A validated osseo-ligamentous model from C2-C7 was used in this study.

Biomechanical analysis of laminectomy, laminoplasty, posterior decompression with instrumented fusion, and anterior decompression with fusion for the kyphotic cervical spine.

Purpose: Anterior and posterior decompressions for cervical myelopathy and radiculopathy may lead to clinical improvements. However, patients with kyphotic cervical alignment have sometimes shown poor clinical outcomes with posterior decompression. There is a lack on report of mechanical analysis of the decompression procedures for kyphotic cervical alignment.

Soft Tissue Injury in Cervical Spine Is a Risk Factor for Intersegmental Instability: A Finite Element Analysis.

Objective: Soft tissue cervical spine injury (CSI) has the possibility of causing cervical segmental instability, which can lead to spinal cord injury. There is a lack of certainty in assessing whether soft tissue CSI is unstable or not. This biomechanical study aimed to investigate the risk factors of soft tissue CSI.