Study Design: A retrospective cohort study. Objective: The study retrospectively analyzed the factors associated with the development of adjacent vertebral fractures. Summary of Background Data: Adjacent vertebral fractures (AVF) may occur following cement vertebroplasty, and several risk factors have been reported with controversies. Methods: A total of 123 patients, with a mean age of 79.2 years, who underwent single-level vertebroplasty were included in the investigation. We systematically collected data encompassing baseline demographics, osteoporosis parameters, surgical details, radiologic measurements, and Hounsfield unit (HU) values in the lumbar spine. Subsequently, univariable, followed by multivariable logistic regression analyses, were employed to identify the risk factors of AVFs. Results: Thirty of 123 patients had AVFs within 6 months following vertebroplasty. The AVF group exhibited a higher percentage of multiple preexisting vertebral compression fractures (P=0.006), a greater volume of injected cement (P=0.032), and a more pronounced reduction in local kyphosis (P=0.007). Multivariable logistic regression analysis revealed multiple preexisting vertebral compression fractures and a reduction in local kyphosis exceeding 8 degrees were independent risk factors for AVFs (P=0.008 and 0.003, respectively), with odds ratios of 3.78 (95% confidence interval: 1.41–10.12) and 4.16 (95% CI: 1.65–10.50), respectively. Subgroup analysis showed that patients with multiple preexisting vertebral compression fractures (VCFs) had significantly lower bone mineral density Z-score, T-score, and HU values compared with those without preexisting VCFs (P<0.05). Conversely, there were no significant differences in T-score or HU values between patients with no VCFs and those with a single VCF. Conclusion: This study demonstrated that both bone strength and local alignment are key factors associated with adjacent vertebral fractures. Specifically, having multiple preexisting vertebral compression fractures and a reduction in local kyphosis exceeding 8 degrees are independent risk factors. The presence of more than one previous vertebral compression fracture serves as a significant clinical indicator of advanced bone density reduction in patients with osteoporosis, offering a quick and straightforward method for identifying high-risk patients. Patients exhibiting these risk factors should be monitored more closely for favorable clinical outcomes. Level of Evidence: Level III—retrospective nonexperimental study.

Study Design.: A retrospective, single-center, observational study. Objective.: This study investigated the risk factors associated with the failure of conservative treatment for adjacent vertebral fractures (AVFs). Summary of Background Data.: Adjacent vertebral fractures following vertebroplasty for osteoporotic vertebral compression fractures are not uncommon. Presently, there is a lack of consensus regarding the management of adjacent vertebral fractures. Methods.: We included patients who developed adjacent vertebral fractures within 2 years post single-level vertebroplasty between January 2013 and December 2020. All patients initially underwent 6 weeks of conservative treatment, including pain medications, bracing, and physical therapy. Surgical intervention was offered to those with intractable back pain due to AVFs. Baseline demographics, AVF characteristics, and radiologic measurements were systematically collected, and sequential univariable and multivariable logistic regression analyses were conducted to explore the risk factors. Results.: Of the 114 patients with a mean age of 78.6 years, 2-thirds (76 patients) tolerated conservative treatment well, whereas 38 required surgical interventions for adjacent vertebral fractures. Both groups demonstrated similar baseline demographics and radiologic parameters regarding AVFs (P>0.05). The multivariable logistic regression analyses revealed that the development of AVFs later than 6 months post-vertebroplasty and their caudal location to the index vertebroplasty were the independent risk factors of unsuccessful conservative treatment, with odds ratios of 3.57 (95% confidence interval [CI]: 1.14–11.1, P=0.029) and 2.50 (95% CI, 1.09–5.88, P=0.032), respectively. Conclusion.: Adjacent vertebral fractures following percutaneous vertebroplasty generally have favorable outcomes under conservative treatment. However, the timing and the relative anatomical location of adjacent vertebral fractures are associated with treatment efficacy. Adjacent vertebral fractures occurring later than 6 months following the initial vertebroplasty or situated in the caudal location to the index vertebroplasty may exhibit reduced responsiveness to conservative treatment. These patients might benefit from a more aggressive therapeutic approach. Level of Evidence.: 3

Background: Sustained release of therapeutic factors, such as lovastatin, is theoretically more beneficial than a single injection in promoting anabolic stimulation to nucleus pulposus cells/tissues. This study aimed to develop lovastatin‐loaded nanoparticles (LVS‐NPs) incorporated into thermosensitive chitosan/gelatin/glycerophosphate (C/G/GP) hydrogel for the treatment of intervertebral disc (IVD) degeneration. Methods: LVS‐NPs were prepared using an oil‐in‐water emulsion evaporation method, followed by characterization and drug encapsulation efficiency. LVS‐NPs were then incorporated into C/G/GP hydrogel for controlled drug release, with subsequent in vitro and in vivo evaluations. Results: LVS‐NPs showed a round shape with a mid‐range polydispersity index, which shall benefit lovastatin release. Rheological study showed incorporation of LVS‐NPs into hydrogel does not change thermal gelation property. Drug release tests demonstrated that lovastatin was released steadily from the hydrogel containing LVS‐NPs over 7 days. The LVS‐NPs‐containing hydrogel demonstrated good biocompatibility and low cytotoxicity in the in vitro studies including WST‐8 assay, LDH assay, TUNEL test and Western blot. Analysis of hydrogels containing LVS‐NPs on human nucleus pulposus cells revealed enhanced production of aggrecan and Type II collagen without inducing apoptosis, though higher concentrations or longer treatment durations may be required to achieve effects comparable to those of 5 μM lovastatin. In the animal study, various treatment regimens were applied to a rat caudal disc model mimicking early‐stage IVD degeneration. Despite lovastatin or LVS‐NPs in hydrogel, significant decreases in disc height index and extensive degeneration observed through MRI and histological staining indicated a complete loss of nucleus pulposus tissue in all hydrogel‐treated groups, likely due to mechanical compression from the injected hydrogel within the confined space of the annulus fibrosus, which needs further investigation. Conclusions: LVS‐NPs demonstrated sustained release of lovastatin and extended stimulatory effects on human nucleus pulposus cells in vitro. However, further research is needed to optimize the hydrogel volume and its ratio to intradiscal space and increase lovastatin concentration within LVS‐NPs to achieve optimal therapeutic outcomes while minimizing mechanical compression to surrounding tissues.