Treatment of lumbar spondylolysis in young adults using modified intravertebral screw-rod fixation system for single vertebral body combined with autologous cancellous bone graft: a technical note and preliminary report

Background There is currently no consensus on the surgical treatment of lumbar spondylolysis in young adults, and the nonunion rate remains relatively high even after surgery. Therefore, in this study, we proposed a modified intravertebral screw-rod fixation technique within a single vertebral segment and investigated the clinical efficacy of this modified fixation system combined with autologous cancellous bone grafting in the treatment of lumbar spondylolysis in young adults. Methods This study included 28 young adults with lumbar spondylolysis who were treated at our center between 2021 and 2023. All patients underwent modified intravertebral screw-rod fixation within a single vertebral segment combined with autologous cancellous bone grafting. We performed postoperative follow-ups regularly to assess the patient's pain status using the visual analog scale (VAS), Oswestry Disability Index (ODI), and radiological findings. Results All 28 patients successfully underwent the surgery with an average operation time and blood loss volume of 96.01 +/- 21.3 min and 186.78 +/- 63.43 mL, respectively. Postoperatively, patients experienced significant symptom relief, with notable decreases in VAS scores and ODI indices at 1, 3, 6, and 12 months compared with preoperative conditions. These differences were statistically significant (P < 0.05). Radiological findings revealed a healing rate of 92.86% for the 56 fractured pars interarticularis among the 28 patients. No implant-related complications, such as fracture, loosening, or pseudarthrosis, were observed. Conclusions The modified intravertebral screw-rod fixation system within a single vertebral segment combined with autologous cancellous bone grafting is a safe and effective treatment for lumbar spondylolysis in young adults. It significantly improves pain and functional disability as it promotes bone healing.