Long term outcome of posterior lumbar pedicle screw fixation combined with isthmic bone graft fusion in the treatment of lumbar spondylolysis in young patients

Abstract

To investigate the long-term effect of posterior lumbar pedicle screw fixation combined with isthmus bone grafting and fusion in young patients with spondylolysis. A retrospective study was carried out, consisting of 16 young patients with lumbar spondylolysis without spondylolisthesis treated by lumbar posterior pedicle screw fixation combined with isthmic bone grafting fusion from January 2006 to July 2014. There were 11 males and 5 females, aged from 18 to 21 years old, with an average age of 19.3 years old, and the course of disease ranged from 12 to 26 months, with an average of 22 months. All the patients suffered from lumbar pain and difficulty in getting out of bed. Preoperative CT confirmed 12 cases of L₅ isthmus fissure and 4 cases of L₄ isthmus fissure. Bone graft fusion was confirmed and internal fixation was removed after operation. Lumbar spondylolysis was evaluated by lumbago visual analogue scoring method at preoperative and postoperative time points. Lumbar isthmic fusion was evaluated by lumbar CT, and degeneration of fixed and adjacent segments of lumbar intervertebral disc was evaluated by lumbar MRI. Of the 16 patients, 13 patients (26 sides) were followed up, with a mean duration of 96 months. The operation time ranged from 80 to 105 minutes, with an average of 95 minutes. The intraoperative bleeding volume ranged from 150 to 300 ml, with an average of 225 ml. All the patients were successfully operated without any complications related to the operation. VAS scores at each time point after operation were improved compared with those before operation(P<0.01). Postoperative CT scans of lumbar spine showed osseous fusion at 6 to 14 months, with an average of 12 months. There were no changes of adjacent segment degeneration, fixed segment disc degeneration and protrusion on lumbar spine MRI, and no symptomatic recurrence or recurrent spondylolysis in the long term. The posterior lumbar pedicle screw fixation combined with isthmic bone grafting and fusion is safe and effective in the treatment of young spondylolysis. The fusion rate is high and the interference of normal physiological range is reduced. The long-term effect is satisfactory.