Traditional lecture-based learning (LBL) faces limitations in teaching complex spinal anatomy and surgical procedures. This study aimed to evaluate the eff

The atlantoaxial lateral mass joint is a pivotal structure facilitating cervical rotation and flexion-extension. Its morphological characteristics are intrinsically linked to degenerative pathologies and segmental instability. However, comprehensive three-dimensional anatomical data, particularly regarding sex-specific variations, remain insufficient. This study aimed to perform precise three-dimensional measurements of the atlantoaxial lateral mass joint in normal adults to elucidate its normative morphological features and sexual dimorphism, which may serve as a morphological reference for future studies exploring surgical planning, personalized implant design, and biomechanical modeling. A retrospective analysis was conducted on 200 patients (100 males, 100 females; aged 18-50 years) without cervical abnormalities, using cervical three-dimensional spiral CT images obtained between December 2024 and December 2025. Parameters measured on reconstructed images included the anteroposterior diameter (sagittal plane), left-right diameter (coronal plane), medial inclination angle, joint space width, and distance from the transverse foramen to the lateral mass joint midpoint. Statistical analysis employed independent samples t-tests to evaluate sex differences. All parameters exhibited significant sex differences (P < 0.05). Males consistently demonstrated significantly larger anatomical dimensions than females across all linear and angular metrics. Notably, these sex-related differences remained significant after adjusting for Body Mass Index (BMI) via ANCOVA (P < 0.05), indicating that the observed dimorphism reflects intrinsic biological traits rather than overall body habitus. This study systematically quantifies the three-dimensional anatomy of the atlantoaxial lateral mass joint and confirms significant sexual dimorphism.These findings offer morphological context that may be relevant when investigating atlantoaxial pathologies and provide anatomical baseline data for future research concerning personalized fusion device design, surgical navigation, and finite element simulations.

Objective: This finite element analysis study aimed to compare the biomechanical behavior of anterior cervical discectomy and fusion (ACDF) with circumferential cervical fusion (CCF) across one-, two-, and three-level constructs, to elucidate the length-dependent contribution of supplemental posterior fixation. Methods: A C3-C7 finite element model was developed from CT scans. Seven scenarios were simulated: intact spine; 1-, 2-, and 3-level ACDF; and corresponding CCF constructs (ACDF plus bilateral posterior facet cages). A 73.6 N axial load with ±1.0 Nm moments simulated flexion, extension, lateral bending, and axial rotation. Stress on vertebrae, instrumentation, and adjacent segments (C3/4, C5/6, C6/7 facet capsules and discs) was analyzed. Results: The biomechanical benefit of CCF was length-dependent. It reduced anterior plate stress relative to ACDF, with increasing reduction for longer constructs (8%–12% for 1-level, 10%–18% for 2-level, 15%–25% for 3-level). CCF provided greater vertebral stress shielding. All fusions increased adjacent facet capsule stress, slightly more with CCF. However, CCF resulted in lower increases in adjacent disc stress than ACDF (e.g., at C6/7 disc: +1.6% for 3-level CCF vs. +5.8% for ACDF). Conclusions: One-level ACDF provides sufficient stability. For two-level constructs, posterior fixation offers measurable protection, beneficial for high-risk patients. For three-level constructs, CCF effectively mitigates the significant anterior stress concentration and elevated adjacent disc stress associated with standalone ACDF, despite a minor increase in facet capsule stress. Posterior augmentation should be considered based on construct length.

Purpose: To investigate the factors influencing refracture after percutaneous kyphoplasty and to develop and validate a prognostic model.Method: We retrospectively collected clinical data in 392 patients with osteoporotic vertebral compression fractures who underwent percutaneous kyphoplasty at the Affiliated Hospital of Xuzhou Medical University from 1 January 2018 to 1 January 2020.Predictors significantly associated with refracture after PKP were selected based on last absolute shrinkage and selection operator regression. Then a prognostic model were developed and internal validated using enhanced Bootstrap validation.Results: Among the 392 patients who included in this study, there were 19 refracture after percutaneous kyphoplasty(4.8%). Four factors were selected by least absolute shrinkage and selection operator regression for significant association with refracture after percutaneous kyphoplasty, including body mass index, bone mineral density, unilateral puncture, and bone cement leakage. After enhance Bootstrap validation, the bias-corrected curve of the model fitted well with the apparent curve, with the area under ROC curve of 0.931 and 95% CI of (0.789,0.936).Conclusion: The prognostic model developed based on four clinical profiles: body mass index, bone mineral density, unilateral puncture, and bone cement leakage can be used to identify those at most risk of refracture after percutaneous kyphoplasty.

Anterior cervical discectomy and fusion (ACDF) is a well-established treatment for cervical degenerative disease (CDD). Nevertheless, its anterior approach carries inherent risks to critical neck structures, prompting the exploration of posterior fusion alternatives for selected patients. Traditional anterior cervical discectomy and fusion (ACDF) for cervical degenerative disease involves navigating complex anterior neck anatomy with potential risks to critical neurovascular structures, motivating the development of safer posterior fusion alternatives. Twenty-four fresh C5-C6 segments from adult goats were randomly assigned to the intact, ACDF, and CILC groups (n = 8 per group). After confirming the anatomical similarity between goat and human cervical spines via three-dimensional reconstruction, corresponding surgical procedures were performed at the C5-C6 level. Range of motions (ROMs) in flexion-extension, lateral bending, and axial rotation were measured under a pure moment of 1.5 N·m using a material testing machine. A finite element model of C3-C7 was developed based on computed tomography data from healthy adults. ACDF and CILC procedures were simulated, with a 1 N·m moment and 73.6 N pre-load applied to analyse the stress distribution in adjacent segment discs, facet cartilage, and implants. Anatomical measurements confirmed a high similarity between goat and human C5-C6 segments (P > 0.05), validating its use as an experimental model. In biomechanical tests, both CILC and ACDF significantly reduced segmental motion (P < 0.001). Compared with ACDF, CILC demonstrated greater ROM in flexion (3.31° vs. 1.52°, P < 0.05), but superior stability in extension (1.86° vs. 3.86°) and axial rotation (left: 5.89° vs. 8.19°; right: 6.11° vs. 8.89°) (P < 0.05). Finite element analysis confirmed model reliability, demonstrating close alignment between predicted and reported ROM values. CILC generated lower or comparable stress in C3/4 and C4/5 discs compared with ACDF, but higher stress at C5/6. Moreover, CILC resulted in higher facet joint contact forces and implant stress than ACDF, particularly during flexion and extension. Although CILC demonstrates biomechanical performance comparable to ACDF with specific advantages in controlling extension and axial rotation without significant advantages, its posterior minimally invasive approach effectively avoids neurovascular risks associated with anterior surgery. The device provides a safer alternative for cervical fusion, particularly in cases with complex anterior anatomy or those requiring revision surgery. However, the observed higher facet and implant stresses underscore the need for careful patient selection, particularly regarding pre-existing facet joint condition and bone quality.