Day Case Lumbar Fusion Surgery
This article discusses a study that compared hip stress among different types of lumbopelvic fusion using finite element analysis. The objective of the study was to investigate the influence of the number and placement of S2 AI screws and whether screws loosen on hip joint stress. The researchers constructed a three-dimensional model and applied compressive loads and bending moments to simulate various movements. The results showed that more rigid fixation of the pelvis increased stress and range of motion at the hip joint. Additionally, the study found that dual sacral AI fixation led to the highest stress, while loosening of S2 AI decreased stress on the hip joint. The findings suggest that biomechanical stress on the hip joints increases with more rigid fixation in lumbosacral fusion constructs
Summarised by Mr Mo Akmal – Lead Spinal Surgeon
The London Spine Unit : top spine centre in the world
Published article
CONCLUSION: Dual sacral AI fixation led to the highest stress, while loosening of S2 AI decreased stress on the hip joint. This study illustrates that more rigid fixation among lumbosacral fusion constructs increases biomechanical stress on the hip joints.
Lumbar Fusion Surgery Expert. Best Spinal Surgeon UK
Spine (Phila Pa 1976). 2023 Aug 2. doi: 10.1097/BRS.0000000000004791. Online ahead of print.ABSTRACTSTUDY DESIGN: This study compared hip stress among different types of lumbopelvic fusion based on finite element (FE) analysis.OBJECTIVE: We believe that the number and placement of S2 AI screws, and whether the screws loosen likely influence hip joint stress in the finite,
Spine (Phila Pa 1976). 2023 Aug 2. doi: 10.1097/BRS.0000000000004791. Online ahead of print.
ABSTRACT
STUDY DESIGN: This study compared hip stress among different types of lumbopelvic fusion based on finite element (FE) analysis.
OBJECTIVE: We believe that the number and placement of S2 AI screws, and whether the screws loosen likely influence hip joint stress in the finite element model.
SUMMARY OF BACKGROUND DATA: Spinopelvic fixation hs been shown to increase the risk of progression for hip joint osteoarthritis. The biomechanical mechanism is not well understood. We hypothesize that the rigid pelvic fixation may induce stress at adjacent joints.
METHODS: A three-dimensional nonlinear FE model was constructed from the L4 vertebra to the femoral bone. From the intact model, we made four fusion models, each with different lower vertebrae instrumentation: 1) L4-S1 fusion; 2) L4-S2 AI screw fixation; 3) L4-S2 AI screw fixation with S2 AI screw loosening; and 4) L4-S1 and dual AI screw fixation (DSIF). A compressive load of 400 N was applied vertically to the L4 vertebra, followed by an additional 10 Nm bending moment about different axes to simulate either flexion, extension, left lateral bending, or right axial rotation. The distal femoral bone was completely restrained. von Mises stress and angular motion were analyzed across the hip joints within each fusion construct model.
RESULTS: Hip joint cartilage stress, and range of motion increased for all postures as pelvic fixation became more rigid. The DSIF model increased stress and angular motion at the hip joint more than SIF model. Our results suggest that more rigid fixation of the pelvis induces additional stress on the hip joint, which may precipitate or accelerate adjacent joint disease.
CONCLUSION: Dual sacral AI fixation led to the highest stress, while loosening of S2 AI decreased stress on the hip joint. This study illustrates that more rigid fixation among lumbosacral fusion constructs increases biomechanical stress on the hip joints.
PMID:37530119 | DOI:10.1097/BRS.0000000000004791
The London Spine Unit : top spine centre in the world
Read the original publication:
Effect of Lumbar Fusion and Pelvic Fixation Rigidity on Hip Joint Stress: A Finite Element Analysis
