Space between bone cement and bony endplate can trigger higher incidence of augmented vertebral collapse: An in-silico study.

BACKGROUND: The pathogenesis of postoperative complications in patients with osteoporotic vertebral compressive fractures (OVCFs) undergoing percutaneous vertebroplasty (PVP) is multifaceted, with local biomechanical deterioration playing a pivotal role. Specifically, the disparity in stiffness between the bone cement and osteoporotic cancellous bone can precipitate interfacial stress concentrations, potentially leading to cement-augmented vertebral body collapse and clinical symptom recurrence. This study focuses on the biomechanical implications of the space between the bone cement and bony endplate (BEP), hypothesizing that this interface may be a critical locus for stress concentration and subsequent vertebral failure. METHODS: Leveraging a validated numerical model from our previous study, we examined the biomechanical impact of the cement-BEP interface in the L2 vertebral body post-PVP, simulated OVCF and PVP and constructed three distinct models: one with direct bone cement contact with both cranial and caudal BEPs, one with contact only with the caudal BEPs and one without contact with either BEP. Moreover, we assessed stress distribution across cranial and caudal BEPs under various loading conditions to describe the biomechanical outcomes associated with each model. RESULTS: A consistent trend was observed across all models: the interfaces between the bone cement and cancellous bone exhibited higher stress values under the majority of loading conditions compared to models with direct cement-BEP contact. The most significant difference was observed in the flexion loading condition compared to the mode with direct contact between BEP and cement. The maximum stress in models without direct contact increased by at least 30%. CONCLUSIONS: Our study reveals the biomechanical significance of interfacial stiffness differences at the cement-BEP junction, which can exacerbate local stress concentrations and predispose to augmented vertebral collapse. We recommend the strategic distribution of bone cement to encompass a broader contact area with the BEP for preventing biomechanical failure and subsequent vertebral collapse.

Analysis of the Curative Effect of Curved Angle Vertebroplasty in the Treatment of Osteoporotic Vertebral Compression Fracture.

Objective: To evaluate the clinical efficacy of Percutaneous curved vertebroplasty (PCVP) for osteoporotic vertebral compression fracture of the thoracolumbar spine. Methods: Retrospective analysis of 113 patients with osteoporotic vertebral compressive fractures (OVCFs) in our hospital from January 2017 to January 2020, a total of 120 diseased vertebrae, were divided into PCVP group (35 cases, 37 sections) and bilateral PVP(BVP) group (78 cases, 83 sections). To compare the distribution of baseline clinical data, pain relief (Visual Analog Scale, VAS), ODI (Oswestry Dability Index, ODI), operation time, intraoperative fluoroscopy, postoperative vertebral body re-fracture, and comparison of bone, and to compare the volume of cement penetration and the leakage rate of bone cement, etc. Results: There was no significant difference in VAS and ODI before operation between the two groups (P > 0.05), and the VAS score and ODI after operation were significantly improved (P < 0.001). Compared with the bilateral PVP group, the operation time, the number of fluoroscopy, and the leakage rate of each layer of bone cement in the PCVP group were significantly reduced (P < 0.05); however, the amount of cement used in the two groups was similar (P > 0.05). There were no serious complications in both groups. In the bilateral PVP group, a total of seven patients had adjacent vertebral fractures or re-fractures of the original vertebral body. However, no patients in the PCVP group had re-fractures in any vertebral body segment. Conclusion: Both PCVP and bilateral PVP are safe and effective methods for the treatment of osteoporotic vertebral compression fractures, but PCVP has a short operation time, fewer fluoroscopy times, and a low bone cement leakage rate.