Investigating biomechanical differences in lumbosacral transitional vertebrae among different Castellvi...

Area of Science:

• Biomechanics
• Spinal Anatomy
• Computational Modeling

Background:

• Lumbosacral transitional vertebrae (LSTV) are common anatomical variations.
• The biomechanical consequences of different LSTV classifications remain incompletely understood.
• Understanding these differences is crucial for diagnosing and managing associated low back pain.

Purpose of the Study:

• To investigate the biomechanical differences among various Castellvi classifications of LSTV.
• To analyze stress and displacement patterns in the lumbar-pelvic complex with different LSTV types.
• To correlate LSTV classifications with potential low back pain mechanisms.

Main Methods:

• Finite element analysis (FEA) was employed using CT data of a healthy adult.
• Seven LSTV models (Castellvi types IA, IB, IIA, IIB, IIIA, IIIB, IV) and a normal model were created.
• Simulated axial compression and torque were applied to evaluate displacement and Mises stress in intervertebral discs and sacroiliac joints.

Main Results:

• LSTV Types IIIA, IIIB, and IV showed significantly lower global displacement under all loading conditions.
• Types IIIB and IV significantly reduced intervertebral disc stress, while IA and IIA increased it under certain conditions.
• Types IIIB and IV significantly increased sacroiliac joint stress, whereas IB and IIB showed stress reduction.

Conclusions:

• Different Castellvi classifications of LSTV significantly alter lumbar-pelvic biomechanics.
• High-grade LSTV types (IIIB, IV) increase sacroiliac joint stress, potentially leading to dysfunction.
• Low-grade LSTV types (IA, IIA) may increase discogenic low back pain risk due to altered stress distribution.