1. 2025;28;E535-E546A Comparative Analysis of Single versus Double Intravertebral Reduction Device Implantation for Single-Level Osteoporotic Vertebral Fractures: Radiological and Clinical Outcomes
   Observational Study
   Yuan-Fu Liu, MD, Hao-Jun Chuang, MD, Yu-Chia Hsu, MD, Fu-Yao Fan, MD, Chao-Jui Chang, MD, and Cheng-Li Lin, MS.

BACKGROUND: Intravertebral reduction devices have been used for treating osteoporotic vertebral fractures (OVFs), with the advantage of fracture reduction before cement injection and the potential to prevent the secondary loss of vertebral height. While double devices via bipedicle insertion are commonly recommended, there is currently no report on the safety and efficacy of using a single device to treat OVFs.

OBJECTIVE: This study aims to compare the radiological and clinical outcomes of single intravertebral reduction device implantation to those of double intravertebral reduction device implantation in the treatment of single-level OVFs.

STUDY DESIGN: Observational cohort study.

SETTING: The study was conducted at a tertiary medical center. Data were collected by reviewing the electronic medical records of a consecutive series of individuals from January 2015 to December 2020.

METHODS: Patients with single-level OVFs between T8 and L4 who underwent single (n = 27) or double (n = 56) intravertebral device implantation were included in the study and analyzed. Outcome measures included radiographic assessments and the evaluation of clinical outcomes. Multiple linear regression analysis was used to examine the associations among the number of implants, body mass index (BMI), bone mineral density, and presence of radiographic vacuum clefts on vertebral height correction.

RESULTS: Both the single- and double-device groups demonstrated significant improvements in fracture reduction and functional outcomes. The single-device group had a shorter operating time (36.0 ± 2.82 min vs. 62.92 ± 16.49 min, P = 0.012) and lower cement volume usage (3.60 ± 0.00 mL vs. 5.04 ± 1.56 mL, P = 0.032).
However, the double-device group showed greater improvement in anterior vertebral height (7.02 ± 3.34 mm, 95% CI: 6.13–7.91 vs. 5.24 ± 3.94 mm, 95% CI: 3.68–6.80, p = 0.034) and regional kyphotic angle correction (6.79 ± 6.50°, 95% CI: 4.83–8.75 vs. 2.79 ± 6.79°, 95% CI: 0.10–5.48, P = 0.011). Despite these radiological differences, long-term functional outcomes at the last follow-up were comparable between groups. There were no significant differences in complication rates between the 2 groups. Higher BMI and the presence of an intravertebral vacuum cleft appeared as potential risk factors for the re-collapse of vertebral body height.

LIMITATIONS: This study is retrospective and has inherent limitations related to sample size and variability. Some measurements showed a high degree of variability, which could have led to overlapping confidence intervals and a potential risk of Type II errors.

CONCLUSION: Single intravertebral reduction device implantation is an effective and safe treatment option for OVFs, yielding clinical outcomes comparable to those of double device implantation. Additionally, certain risk factors, such as higher BMI and the presence of an intravertebral vacuum cleft, should be evaluated carefully, since they may contribute to vertebral height re-collapse following expandable device augmentation. However, prospective randomized controlled trials are still warranted to further evaluate the efficacy of single versus double device implantation.

KEY WORDS: Osteoporotic fracture, spinal fractures, kyphoplasty, intravertebral device, uni-pedicle approach, vertebral height, kyphotic angle, coronal angle