Comparison of cortical bone trajectory screw fixation and pedicle screw fixation in posterior lumbar fusion

Objective To evaluate the efficacy and safety of cortical screw fixation in posterior lumbar spine fixation with cortical bone trajectory (CBT) fixation or pedicle screw (PS) fixation in posterior lumbar fusion. Methods It was a prospective study and CBT or PS for the treatment of lumbar disease from August 2015 to August 2017 in Beijing Chaoyang Hospital were analyzed. There were 53 males and 51 females, aged 56-78 years (mean age, (67±5) years). The patient′s gender, age, operative time, intraoperative blood loss, postoperative bleeding, postoperative hospital stay, and postoperative patient satisfaction were collected. The Oswestry disability index (ODI) and visual analogue scale (VAS) of back pain were used to evaluate preoperative and half-year, one-year and two-year postoperative function and quality of life. Complications such as wound infection, cage displacement, screw extraction and fixation fracture were compared between the two groups. The data of normal distribution were compared with Student t test between the two groups. Results There was no significant difference in the operation time between the CBT group (n=50) and the PS group (n=54) ((223±17) min vs (221±16) min, t=0.74, P=0.46). The intraoperative blood loss and wound drainage volume were significantly lower in the CBT group than those in the PS screw group (t=-24.20, -57.62, both P<0.05). The average length of hospital stay in the CBT group was significantly shorter than that in the PS group (t=-7.65, P=0.00). Patients with CBT screws had better postoperative satisfaction than patients in PS group (91±6 vs 86±7, t=3.89, P=0.00). The ODI score in the CBT group was significantly lower than that in the PD screw group half a year after the operation (3.9±1.9 vs 5.8±3.1, t=-3.66, P=0.00). The VAS and ODI scores in the CBT group were significantly lower than those in the PS group 1 year after the surgery (t=-3.03, -4.09, both P<0.05). There was no significant differences in wound infection, cage displacement, screw extraction and fixation fracture between the two groups. Conclusion CBT screw technique is minimally invasive, with short operation time, less intraoperative blood loss, rapid postoperative recovery and low complications. It can be effectively used in posterior lumbar cone fusion. Key words: Posterior lumbar interbody fusion; Cortical bone trajectory; Pedicle screw