RESUMEN
OBJECTIVE: Percutaneous vertebroplasty (PVP) is currently the most common surgical procedure for unstable Kummell disease (KD), but cement loosening or displacement often occurs after PVP. We had been using percutaneous pediculoplasty (PPP) or a self-developed bone cement bridging screw system to avoid this severe complication. This study intends to compare these novel surgical procedures through a 2-year follow-up evaluation. METHODS: From May 2017 to May 2021, 77 patients with single-level unstable KD were included in the PPP group, and 42 patients received the PVP-bone cement bridging screw system were included in the screw group. The changes in the vertebral body index (VBI), bisegmental Cobb angle, visual analogue scale (VAS) and Oswestry Disability Index (ODI) and the cement loosening rate and displacement rate at different follow-up time points were used to evaluate the clinical efficacy. RESULTS: There was no significant difference in VBI or bisegmental Cobb angle between the 2 groups (p > 0.05) before operation, immediately after operation and at 6-month followup, while at 1-year and 2-year postoperative evaluations, the screw group had higher VBI and bisegmental Cobb angle than the PPP group (p < 0.05). Before operation, immediately after operation, at 6-month and 1-year follow-up, there was no significant difference in VAS or ODI score between the 2 groups (p > 0.05), while at 2-year follow-up, the screw group still had higher VAS and ODI scores than the PPP group (p < 0.05). No bone cement displacement occurred in both groups, but the rate of bone cement loosening was 14.29% in group PPP, and 0 in screw group (p < 0.05). CONCLUSION: This 2-year follow-up study shows that the PVP-bone cement bridging screw system combined therapy had better midterm treatment efficacy than the PVP-PPP combined therapy in patients with unstable KD, and the bone cement bridging screw system is a preferred therapy with better anti cement loosening ability.
RESUMEN
When bone cement is used to strengthen the vertebrae in patients with Kummell disease (KD), loosening and displacement of cement are common complications that can cause poor results. We developed a bone cement bridging screw system to avoid this complication. This three-dimensional finite element study aims to analyze the biomechanical properties of the novel bridging screw system and compare it to single vertebroplasty and vertebroplasty combined with pediculoplasty. After the effective establishment of a KD three-dimensional finite element model, the stability of the bone cement in the five treatment methods was analyzed and compared on four aspects. According to the calculation results of the maximum von Mises stress of bone cement and the relative displacement ratio of bone cement, it was determined that the stability of the bone cement was significantly improved when combined with the bridging screw system or pediculoplasty. In addition, according to the calculation results of the maximum von Mises stress of the inferior endplate of T12 and the displacement load ratio of the bone cement, we further found that after using the bridging screw system, the bone cement in the vertebral body has the best stability, and the risk of bone cement loosening or displacement is the lowest. In conclusion, for treating KD with bone cement augmentation, the bone cement bridging screw system combined with vertebroplasty has better stability and safety than ordinary single vertebroplasty and vertebroplasty combined with pediculoplasty. This treatment approach has the most robust ability to avoid loosening and displacement of bone cement.