Implications of Different Types of Decompression Spinal Stenosis Surgical Procedures on the Biomechanics of Lumbar Spine

Purpose In this paper, a 3D finite element model of L-1-L-5 region in spinal column was developed to investigate biomechanical behavior of spine under different types of decompression surgery, which will help spinal surgeons to have a patient-specific computational tool for optimizing surgical treatment of spinal canal pathologies. Methods In this study, a new theoretical approach was developed to evaluate and compare different spinal surgical procedures using finite element model of lumbar spine. This model was developed by using computed tomography scanning (CT scan) of a patient with spinal canal stenosis and the computer-aided design (CAD) software was used to virtually simulate different types of surgery. The results of simulations were verified and validated through experimental data from the literature and a good agreement was found between the results. Four different types of spinal surgical procedures including unilateral laminotomy, bilateral laminotomy, laminectomy with complete facetectomy, and laminectomy with partial facetectomy were virtually simulated in model. Results Post-operative kinematics, various biomechanical relevant parameters of spine, such as intradiscal pressure, disc stresses, and stresses at adjacent segments were evaluated by simulating each surgical procedure and optimal procedure was specified. Results showed that laminectomy with complete facetectomy leads to big changes in spinal stability and larger intradiscal pressure and stress at the operated segment (up to 150% in comparison with intact spine). Conclusion Our results represented that laminotomy is an optimal technique to reduce potential risk of adjacent segment disease and spinal instability.