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Background: Current research lacks comprehensive investigation into the biomechanical changes in the spinal cord and nerve roots during scoliosis correction. This study employs finite element analysis to extensively explore these biomechanical variations across different Cobb angles, providing valuable insights for clinical treatment. Methods: A personalized finite element model, incorporating vertebrae, ligaments, spinal cord, and nerve roots, was constructed using engineering software. Forces and displacements were applied to achieve Cobb angle improvements, designating T1/2-T4/5 as the upper segment, T5/6-T8/9 as the middle segment, and T9/10-L1/2 as the lower segment. Simulations under traction, pushing, and traction + torsion conditions were conducted, and biomechanical changes in each spinal cord segment and nerve roots were analyzed. Results: Throughout the scoliosis correction process, the middle spinal cord segment consistently exhibited a risk of injury under various conditions and displacements. The lower spinal cord segment showed no significant injury changes under traction + torsion conditions. In the early correction phase, the upper spinal cord segment demonstrated a risk of injury under all conditions, and the lower spinal cord segment presented a risk of injury under pushing conditions. Traction conditions posed a risk of nerve injury on both sides in the middle and lower segments. Under pushing conditions, there was a risk of nerve injury on both sides in all segments. Traction + torsion conditions implicated a risk of injury to the right nerves in the upper segment, both sides in the middle segment, and the left side in the lower segment. In the later correction stage, there was a risk of injury to the upper spinal cord segment under traction + torsion conditions, the left nerves in the middle segment under traction conditions, and the right nerves in the upper segment under pushing conditions. Conclusion: When the correction rate reaches 61–68%, particular attention should be given to the upper-mid spinal cord. Pushing conditions also warrant attention to the lower spinal cord and the nerve roots on both sides of the main thoracic curve. Traction conditions require attention to nerve roots bilaterally in the middle and lower segments, while traction combined with torsion conditions necessitate focus on the right-side nerve roots in the upper segment, both sides in the middle segment, and the left-side nerve roots in the lower segment. [ABSTRACT FROM AUTHOR]

Background: Anterior cervical diskectomy and fusion (ACDF) has been widely accepted as a gold standard for patients with cervical spondylotic myelopathy (CSM). However, there was insufficient evidence to compare the changes in the cervical alignment with different fusion devices in a long follow-up period. This meta-analysis was performed to compare the radiologic outcomes and loss of correction (LOC) in cervical alignment of Zero-profile (ZP) device versus cage-plate (CP) construct for the treatment of CSM. Methods: Retrospective and prospective studies directly comparing the outcomes between the ZP device and CP construct in ACDF were included. Data extraction was conducted and study quality was assessed independently. A meta-analysis was carried out by using fixed effects and random effects models to calculate the odds ratio and mean difference in the ZP group and the CP group. Results: Fourteen trials with a total of 1067 participants were identified. ZP group had a lower rate of postoperative dysphagia at the 2- or 3-month and 6-month follow-up than CP group, and ZP group was associated with a decreased ASD rate at the last follow-up when compared with the CP group. The pooled data of radiologic outcomes revealed that there was no significant difference in postoperative and last follow-up IDH. However, postoperative and last follow-up cervical Cobb angle was significantly smaller in the ZP group when compared with the CP group. In subgroup analyses, when the length of the last follow-up was less than 3 years, there was no difference between two groups. However, as the last follow-up time increased, cervical Cobb angle was significantly lower in the ZP group when compared with the CP group. Conclusion: Based on the results of our analysis, the application of ZP device in ACDF had a lower rate of postoperative dysphagia and ASD than CP construct. Both devices were safe in anterior cervical surgeries, and they had similar efficacy in correcting radiologic outcomes. However, as the last follow-up time increased, ZP group showed greater changes cervical alignment. In order to clarify the specific significance of LOC, additional large clinical studies with longer follow-up period are required. [ABSTRACT FROM AUTHOR]