Background  Internal fixation is an effective surgical method for the treatment of simple lumbar spondylolysis, but the traditional open surgery is invasive and requires high technical skills. TiRobot-assisted percutaneous screw fixation is accurate and minimally invasive, however, its clinical effect for simple lumbar spondylolysis needs to be analyzed.

  Objective  To investigate the clinical outcomes of the TiRobot-assisted percutaneous screw fixation in the treatment of simple lumbar spondylolysis.

  Methods  A retrospective analysis was performed on 47 patients with simple lumbar spondylolysis treated by screw internal fixation in Beijing Jishuitan Hospital from January to June in 2019. Among them, 24 cases underwent traditional open surgery, and 23 cases underwent percutaneous minimally invasive fixation surgery assisted by TiRobot. The operating time, blood loss, lumbar VAS score and Oswestry disability index before, at 3 days, 3 months and 6 months after operation of the two groups were analyzed. Screw position was evaluated by CT scan at 6 months after surgery, and the clinical results were analyzed.

  Results  There were 15 males and 9 females in the open surgery group (mean age, 24 years) , and 14 males and 9 females in the TiRobot group (mean age, 23 years). The operating time (100.6 ± 12.3 vs 87.5 ± 9.4 min), blood loss (38.7 ± 5.2 vs 5.2 ± 1.1 mL), time to mobilization (21.9 ± 5.7 vs 16.1 ± 5.6 h) and postoperative hospital day (1.3 ± 0.5 vs 2.0 ± 0.5 d) in the TiRobot group were significantly greater than those in the open surgery group. There were no complications occurred in both of the two groups, and no internal fixation failure, no lumbar spondylolisthesis, and no lumbar instability occurred at 6 months after surgery. The low back pain VAS and ODI score at all the postoperative time points were significantly better than those before surgery (P＜0.01), and the low back pain VAS at 3 days after minimally invasive surgery in the TiRobot group was significantly lower than that in the open surgery group (2.04 ± 1.15 vs 3.04 ± 1.12, P＜0.01).

  Conclusion  TiRobot-assisted percutaneous screw internal fixation has a good early treatment effect for young patients with simple lumbar spondylolysis, with minimal invasion and quicker recovery.