Clinical application and efficacy observation of a self-designed transpedicular intravertebral bone grafting device in percutaneous pedicle screw fixation for thoracolumbar fractures

English Keywords:Thoracolumbar fractures  Self-designed bone grafting device  Transpedicular bone grafting  Intravertebral bone grafting  Intravertebral bone defect

English Abstract:

  【Abstract】　Objectives: To investigate the application effect of a self-designed transpedicular intravertebral bone grafting device in percutaneous pedicle screw fixation for thoracolumbar fractures, and to evaluate its safety and the role in preventing the "shell" phenomenon. Methods: A retrospective analysis was performed on 49 patients with thoracolumbar fractures who underwent percutaneous pedicle screw fixation combined with intravertebral bone grafting at our hospital from January 2018 to January 2023. Among them, 25 patients were treated with a self-designed transpedicular intavertebral bone grafting device[Self-designed device group: 8 males, 17 females, aged 48.0±9.7 years; Body mass index(BMI) 21.6±2.7kg/m2; T11 3 cases, T12 9 cases, L1 7 cases, L2 6 cases; Thoracolumbar injury classification and severity(TLICS) score 4.3±0.5; AO classification: A3 18 cases, A4 7 cases]. The other 24 patients were treated with a conventional technique bone grafting funnel(Conventional technique group: 11 males, 13 females, aged 48.2±10.7 years; Body mass index 21.4±2.7kg/m2; T11 6 cases, T12 6 cases, L1 8 cases, L2 4 cases; TLICS score 4.3±0.5; AO classification: A3 17 cases, A4 7 cases). There were no statistically significant differences between the two groups in age, gender ratio, body mass index, fracture level, AO classification, or TLICS score(P>0.05). The total operativetime, graft implantation time, fluoroscopy frequency during bone grafting, intraoperative blood loss, hospital stay, and intraoperative complications were compared between the two groups. Low back pain was assessed using visual analogue scale(VAS) score, lumbar function was evaluated using Oswestry disability index(ODI) and Japanese Orthopaedic Association(JOA) score preoperatively, at 3 months and 1 year postoperatively. The local kyphotic angle(LKA) and anterior vertebral height ratio(AVHR) were measured and compared preoperatively, immediately postoperatively, at 3 months and 1 year postoperatively. Immediate postoperative CT scan was performed to determine bone graft distribution, assess iatrogenic injuries to the pedicle or anterior vertebral wall, and identify the "shell" phenomenon. Follow-up CT at 1 year postoperatively was performed to evaluate bony fusion and the outcomes of the "shell" phenomenon. Results: All the patients successfully completed the surgery and were followed up for over 12 months(17.0±3.1 months). The self-designed device group was significantly lower in fluoroscopy frequency during bone grafting(11.0±1.5 vs. 13.5±1.7, P<0.05) and longer in graft implantation time(15.0±1.7min vs. 12.7±1.9min, P<0.05) than the conventional technique group, but there was no significant difference in total operative time between the two groups(P>0.05). In the conventional technique group, 3 cases(12.5%) had pedicle injuries, 9 cases(37.5%) had anterior vertebral wall injuries, and 12 cases(50.0%) had bone graft material leakage; In contrast, the self-designed device group had no pedicle or anterior wall injuries, and there were 4 cases(16%) of bone graft leakage. The difference in complication rates between the two groups was statistically significant(P<0.05). Both groups showed significant improvement in LKA and AVHR immediately postoperatively, at 3 months, and at 1 year compared to preoperative values(P<0.05). VAS score, ODI, and JOA score also significantly improved at 3 months and 1 year postoperatively compared to preoperative scores(P<0.05). The "shell" phenomenon occurred in 5 cases in the self-designed device group, with 1 case healed at the 1-year follow-up, which occurred in 8 cases in the conventional technique group, with 2 cases healed at 1 year, and the difference was no statistically significant(P>0.05). Conclusions: The application of the self-designed minimally invasive transpedicular vertebral bone grafting device in percutaneous pedicle screw fixation combined with vertebral bone grafting for thoracolumbar fractures can reduce intraoperative fluoroscopy frequency and complications, therefore to improve surgical safety.