Subsequent fractures after vertebroplasty in osteoporotic vertebral fractures: a meta-analysis

Mechanical characterization and cytocompatibility of linoleic acid modified bone cement for percutaneous cement discoplasty

Minimally invasive spine treatments have been sought after for elderly patients with comorbidities suffering from advanced degenerative disc disease. Percutaneous cement discoplasty (PCD) is one such technique where cement is injected into a degenerated disc with a vacuum phenomenon to relieve patients from pain. Adjacent vertebral fractures (AVFs) are however an inherent risk, particularly for osteoporotic patients, due to the high stiffness of the used cements. While low-modulus cements have been developed for vertebroplasty through the addition of linoleic acid, there are no such variations with a high-viscosity base cement, which is likely needed for the discoplasty application. Therefore, a low-modulus polymethyl methacrylate was developed by the addition of 12%vol. linoleic acid to a high-viscosity bone cement (hv-LA-PMMA). Initial experimental validation of the cement was performed by mechanical testing under compression over a period of 24 weeks, after storage in 37 °C phosphate buffer saline (PBS) solution. Furthermore, cement extracts were used to evaluate residual monomer release and the cytotoxicity of hv-LA-PMMA using fibroblastic cells. Relative to the base commercial cement, a significant reduction of Young's modulus and compressive strength of 36% and 42% was observed, respectively. Compression-tension fatigue tests at 5 MPa gave an average fatigue limit of 31,078 cycles. This was higher than another low-modulus cement and comparable to the fatigue properties of the disc annulus tissue. Monomer release tests showed that hv-LA-PMMA had a significantly higher release between 24 h and 7 days compared to the original bone cement, similarly to other low-modulus cements. Also, the control cement showed cytocompatibility at all time points of extract collection for 20-fold dilution, while hv-LA-PMMA only showed the same for extract collections at day 7. However, the 20-fold dilution was needed for both the control and the hv-LA-PMMA extracts to demonstrate more than 70% fibroblast viability at day 7. In conclusion, the mechanical testing showed promise in the use of linoleic acid in combination with a high-viscosity PMMA cement to achieve properties adequate to the application. Further testing and in vivo studies are however required to fully evaluate the mechanical performance and biocompatibility of hv-LA-PMMA for possible future clinical application.

The Closer Vicinity to Treated Vertebrae in Percutaneous Vertebroplasty, the Higher Rate of New Vertebral Compression Fractures at Follow-up

OBJECTIVE

To investigate whether risk of new vertebral compression fractures (NVCFs) was associated with vicinity to treated vertebrae in percutaneous vertebroplasty (PVP) for osteoporotic vertebral compression fractures (OVCFs).

METHODS

All OVCF (T6-L5) patients treated with PVP between January 2016 and December 2020 were retrospectively reviewed. Vicinity to treated vertebrae was defined as the number of vertebrae between an untreated and its closest treated level. The closest treated level was chosen as reference vertebra. Clinical, radiologic, and surgical parameters were compared between groups of reference vertebrae for each vicinity NVCF.

RESULTS

In total, 1348 patients with 1592 fractured and 14,584 normal vertebrae were enrolled. NVCF was identified in 20.1% (271 of 1348) patients in 2.2% (319 of 14584) vertebrae in a mean follow-up time of 24.3 ± 11.9 months. Rate of NVCF in vicinity 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11 level were 4.6% (130 of 2808), 2.4% (62 of 2558), 1.8% (42 of 2365), 1.5% (31 of 2131), 1.3% (23 of 1739), 1.3% (17 of 1298), 0.8% (7 of 847), 0.9% (4 of 450), 0.8% (2 of 245), 0.9% (1 of 117), and 0% (0 of 26), respectively. Rate of NVCF in vicinity 1 level was significantly higher than that in vicinity 2, 3, 4, 5, 6, 7, 8, and 9 level, respectively. However, compared to reference vertebrae for vicinity 1 NVCF, any clinical, radiologic, or surgical parameters were not significantly different in those for vicinity 2, 3, and 4 NVCF, respectively.

CONCLUSIONS

The closer vicinity to treated vertebrae in PVP, the higher rate of NVCF at follow-up. However, any clinical, radiologic, or surgical parameters might not matter in this phenomenon of vicinity-related NVCF.

Risk analysis for subsequent fracture of osteoporotic fractures in Chinese women over age 60: a nationwide cross-sectional study

Prevention of subsequent fracture is a major public health challenge in the field of osteoporosis prevention and treatment, and older women are at high risk for osteoporotic fractures. This study aimed to examine factors associated with subsequent fracture in older Chinese women with osteoporosis. We collected data on 9212 older female patients with osteoporotic fractures from 580 medical institutions in 31 provinces of China. Higher odds of subsequent fractures were associated with age of 70-79 years (OR 1.218, 95% CI 1.049-1.414), age ≥ 80 (OR 1.455, 95% CI 1.222-1.732), index fracture site was vertebrae (OR 1.472, 95% CI 1.194-1.815) and hip (OR 1.286, 95% CI 1.041-1.590), index fracture caused by fall (OR 1.822, 95% CI 1.281-2.591), strain (OR 1.587, 95% CI 1.178-2.139), no inducement (OR 1.541, 95% CI 1.043-2.277), and assessed as high risk of fracture (OR 1.865, 95% CI 1.439-2.416), BMD T-score ≤ -2.5 (OR 1.725, 95% CI 1.440-2.067), history of surgery (OR 3.941, 95% CI 3.475-4.471) and trauma (OR 8.075, 95% CI 6.941-9.395). Low risk of fall (OR 0.681, 95% CI 0.513-0.904), use of anti-osteoporosis medication (AOM, OR 0.801, 95% CI 0.693-0.926), and women who had received fall prevention health education (OR 0.583, 95% CI 0.465-0.730) associated with lower risk. The areas under the curve of the prediction model was 0.818. The sensitivity was 67.0% and the specificity was 82.0%. The prediction model showed a good ability to predict the risk of subsequent fracture in older women with osteoporotic fractures and are suitable for early self-measurement which may benefit post-fracture management.

Quasi-static and dynamic mechanical properties of a linoleic acid-modified, low-modulus bone cement for spinal applications

Background

Polymethylmethacrylate (PMMA) bone cement is extensively used in spinal procedures such as vertebroplasty and kyphoplasty, while its use in percutaneous cement discoplasty (PCD) is not yet widely spread. A main issue for both application sites, vertebra and disc, is the mismatch in stiffness between cement and bone, potentially resulting in adjacent vertebral fractures and adjacent segment disease. Tailoring the cement modulus using additives is hence an interesting strategy. However, there is a lack of data on the tensile and tension-compression fatigue properties of these cements, relevant to the newly researched indication of PCD.

Method

A commercial PMMA cement (VS) was modified with 12%vol of linoleic acid (VSLA) and tested for quasi-static tensile properties. Additionally, tension-compression fatigue testing with amplitudes ranging from +/-5MPa to +/-7MPa and +/-9MPa was performed, and a Weibull three-parameter curve fit was used to calculate the fatigue parameters.

Results

Quasi-static testing revealed a significant reduction in VSLA's Young's Modulus (E=581.1±126.4MPa) compared to the original cement (E=1478.1±202.9MPa). Similarly, the ultimate tensile stress decreased from 36.6±1.5MPa to 11.6±0.8MPa. Thus, VSLA offers improved compatibility with trabecular bone properties. Fatigue testing of VSLA revealed that as the stress amplitude increased the Weibull mean number decreased from 3591 to 272 and 91 cycles, respectively. In contrast, the base VS cement reached run-out at the highest stress amplitude. However, the lowest stress amplitude used exceeds the pressures recorded in the disc in vivo, and VSLA displayed a similar fatigue life range to that of the annulus fibrosis tissue.

Conclusions

While the relevance of fully reversed tension-compression fatigue testing can be debated for predicting cement performance in certain spinal applications, the results of this study can serve as a benchmark for comparison of low-modulus cements for the spine. Further investigations are necessary to assess the clinical feasibility and effectiveness of these cements.

A comparative study of PSPVP and PSIBG in the treatment of stage II–III Kummell’s disease

BACKGROUND: Percutaneous kyphoplasty (PKP) or percutaneous vertebroplasty (PVP) are commonly employed for Kummell’s disease in stages II–III; however, these techniques produce some complications. OBJECTIVE: To compare the clinical efficacy and imaging results of percutaneous vertebroplasty + bone cement-augmented short-segment pedicle screw fixation (PSPVP) versus transpedicular intracorporeal bone grafting + pedicle screw fixation (PSIBG) in the treatment of stage II–III Kummell’s disease. METHODS: A total of 69 patients admitted between November 2017 and March 2021 were included in this study; 36 of these were treated with PSPVP, and 33 were treated with PSIBG. Patients in the two groups were compared in terms of perioperative, follow-up, and imaging data. RESULTS: No statistically significant differences were found between the two groups in terms of operation duration (P > 0.05). However, the PSPVP group was superior to the PSIBG group in terms of incision length, intraoperative blood loss, and length of stay (P < 0.05). All patients were followed up for more than 12 months. The VAS score, height of anterior vertebral margin, kyphosis Cobb angle, wedge angle of the affected vertebra at seven days after surgery and last follow-up, and the ODI index at the last follow-up of the two groups were significantly improved compared with figures before surgery (P < 0.05). Compared with values before surgery, no statistically significant differences were found in the height of the posterior vertebral margin in the PSPVP group at seven days after surgery and at the last follow-up (P > 0.05). There were also no statistically significant differences in the VAS score, ODI index, kyphosis Cobb angle, and wedge angle of the affected vertebra between the two groups at corresponding time points (P > 0.05). The heights of the anterior and posterior vertebral margins in the PSIBG group were better than those in the PSPVP group after surgery and at the last follow-up (P < 0.05). In the PSPVP group, a pedicle screw fracture occurred in one patient two months after surgery, while an upper adjacent vertebral fracture occurred in one patient eight months after surgery. CONCLUSION: Both PSPVP and PSIBG can achieve good early clinical efficacy in the treatment of stage II–III Kummell’s disease, with PSPVP being relatively less invasive while producing a poorer orthopedic effect and more complications than PSIBG.

Combined Application of Grid Body Surface Locator and Preemptive Analgesia in Daytime Vertebroplasty

Objective

To explore the clinical advantages of grid body surface locator combined with preemptive analgesia in the treatment of osteoporotic lumbar fractures in daytime vertebroplasty.

Methods

A retrospective study was conducted on 120 patients who underwent lumbar vertebroplasty in the Department of Orthopedics of General Hospital of Northern Theater Command from January 2017 to January 2020. According to the preoperative planning and analgesic mode of treatment, they were divided into the daily operation experimental group and the traditional mode control group. Prone positioning of a patient under anesthetic is safe of ensuring optimum surgical access for many procedures, providing that the risks are fully understood. The general baseline data, intraoperative fluoroscopy times and operation time, bone cement injection volume, bone cement permeability, VAS score before operation, 1 day, and 3 months after operation, and the recovery of anterior vertebral height before and after operation were analyzed.

Results

There was no statistically significant difference in the preoperative general data between the two groups. One day after operation, the VAS score of the experimental group was lower than that of the control group, but there was no difference after 3 months. The permeability of bone cement in the experimental group was lower than that in the control group, the height of anterior edge of injured vertebra was better than that in the control group, and the operation time was less than that in the control group.

Conclusion

The daytime operation experimental group can significantly alleviate postoperative pain, increase the amount of bone cement injection, and reduce the permeability of bone cement through preoperative planning of puncture path and key puncture points, combined with advanced labor pain, but there is no significant difference in long-term pain relief.

Risk factors of new vertebral compression fracture after percutaneous vertebroplasty or percutaneous kyphoplasty

BACKGROUND

New vertebral compression fracture (VCF) may occur in patients who underwent percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP) for osteoporotic vertebral compression fracture (OVCF). However, the risk factors of new VCF remain controversial. The research aimed to analyze the risk factors of new VCF after PVP or PKP.

METHODS

From August 2019 to March 2021, we retrospectively analyzed the patients who underwent PVP or PKP for OVCF at our institution. Age, gender, body mass index (BMI), smoking, drinking, hypertension, diabetes, fracture location, surgical method, Hounsfield unit (HU) value, preoperative degree of anterior vertebral compression (DAVC), bisphosphonates, bone cement volume, bone cement leakage, and cement distribution were collected. The risk factors were obtained by univariate and multivariate analysis of the data.

RESULTS

A total of 247 patients were included in the study. There were 23 patients (9.3%) with new VCF after PVP or PKP. Univariate analysis showed that age (p < 0.001), BMI (p = 0.002), fracture location (p = 0.030), and a low HU value (p < 0.001) were significantly associated with new VCF after PVP or PKP. A low HU value was an independent risk factor for new VCF after PVP or PKP obtained by multivariate regression analysis (OR = 0.963; 95% CI, 0.943-0.984, p = 0.001).

CONCLUSIONS

In this study, a low HU value was an independent risk factor of new VCF after PVP or PKP.