Modified percutaneous vertebroplasty with bilateral cannulated screws and staged cement injection for stage I and II Kummell’s disease: a mid-to-long term follow-up study

Abstract

Abstract Background Kummell’s disease (KD) is a delayed post-traumatic vertebral osteonecrosis often complicated by intravertebral vacuum cleft (IVC), cement loosening, and progressive vertebral collapse after conventional percutaneous vertebroplasty (PVP) or kyphoplasty. This study introduces a modified PVP technique using bilateral cannulated screws and staged cement injection for stage I and II KD, and evaluates its safety, feasibility, and mid-to-long-term clinical and radiological outcomes. Methods A total of 38 patients with stage I (n = 18) or stage II (n = 20) KD were retrospectively enrolled. All underwent a modified procedure under local anesthesia: bilateral pedicle placement of headless cannulated screws, transmidline cement delivery using a steerable cannula (Ascend™), and staged injection (high-viscosity cement followed by low-viscosity cement). Clinical outcomes were assessed by visual analogue scale (VAS) and Oswestry Disability Index (ODI). Radiological outcomes included anterior vertebral height (AVH) and Cobb angle. Evaluations were performed preoperatively, at postoperative day 1, 6 months, 12 months, and at final follow-up (mean 17.2 months). Complications were recorded. Results Significant improvements were observed postoperatively and maintained throughout follow-up. VAS decreased from 6.89 ± 0.87 preoperatively to 1.26 ± 0.61 at final follow-up (P < 0.001). ODI improved from 69.58 ± 9.24% to 17.89 ± 7.03% (P < 0.001). AVH and Cobb angle were both significantly restored at day 1 and remained stable without progressive kyphosis or height loss. Cement extravasation occurred in 15.8% and adjacent vertebral fracture in 5.3%. Stage I patients received larger cement volume than stage II (6.83 ± 1.17 vs. 5.78 ± 1.12 mL, P = 0.008), but final outcomes did not differ between groups (all P > 0.05). Conclusions The modified PVP combining bilateral cannulated screws, steerable cement delivery, and staged injection is safe and feasible for stage I and II KD. It provides sustained pain relief, functional improvement, and durable vertebral height and kyphosis correction, potentially preventing cement loosening and vertebral re-collapse.