Objective:To compare the efficacy of pedicle screw placement between computer navigation guidance and freehand assistance in the surgical treatment of isthmic spondylolysis at the lumbar vertebrae.Methods:A retrospective study was conducted to analyze the 47 patients with bilateral isthmic spondylolysis at the L 5 vertebra who had been treated at Department of Spinal Surgery, The General Hospital of Xinjiang Military Command from January 2020 to April 2023. All were male patients with an age of (24.0±4.3) years. They were divided into a study group (13 cases subjected to pedicle screw placement assisted by computer navigation guidance) and a control group (34 cases subjected to pedicle screw placement assisted freehandedly). The 2 groups were compared in terms of surgical incision length, intraoperative bleeding, screw placement time, postoperative hospital stay, total hospitalization cost, postoperative complications, rate of screw reposition, angle between pedicle screw and upper endplate, angle between bilateral pedicle screws, and placement accuracy; the visual analogue scale (VAS) for pain, Japanese Orthopaedic Association (JOA) score for lumbar spine function, and Oswestry disability index (ODI) were also compared between preoperation, 1-week postoperation, and the last follow-up. Patient satisfaction was assessed according to the modified MacNab criteria, and internal fixation failure and isthmic healing were also evaluated at the last follow-up. Results:There were no statistically significant differences in the preoperative general data between the 2 groups, showing comparability ( P>0.05). The differences were not statistically significant in surgical incision length, intraoperative bleeding, screw placement time, postoperative hospital stay, or postoperative complications ( P>0.05). However, in the study group, the total hospitalization cost was significantly higher than that in the control group, the rate of screw reposition [7.7% (2/26)] significantly lower than that in the study group [26.5% (18/68)], the angle between pedicle screw and upper endplate and the angle between bilateral pedicle screws were both significantly smaller than those in the control group, and the placement accuracy [92.3% (24/26)] was significantly greater than that [70.6% (48/68)] in the control group (all P<0.05). All patients were followed up for 7.0 (5.0, 14.0) months. Patients in both groups showed significant improvements in VAS, JOA score, and ODI at postoperative 1 week and the last follow-up compared with the preoperative values, and the improvements at the last follow-up were significantly larger than those at postoperative 1 week ( P<0.05). According to the modified MacNab criteria at the last follow-up, patient satisfaction was rated as excellent in 10 cases, as good in 2 cases and as moderate in 1 case in the study group while as excellent in 27 cases, as good in 3 cases, as moderate in 3 cases and as poor in 1 case in the control group. In the study group, there were 1 case of internal fixation failure, 1 case of spine cutting-out by titanium cable, and 12 cases of bony healing of the isthmus; in the control group, there were 2 cases of internal fixation failure, 2 cases of spine cutting-out by titanium cable, and 29 cases of bony healing of the isthmus. Conclusions:In the surgical treatment of bilateral isthmic spondylolysis at the L 5 vertebra, computer navigation-guided pedicle screw placement is safe and reliable, showing an advantage of higher accuracy over freehand placement. It deserves clinical promotion due to its satisfactory therapeutic effects.