The efficacy of cortical bone trajectory screw fixation in the treatment of lumbar degenerative disease with osteoporosis

English Keywords:Lumbar degenerative disease  Posterior lumbar interbody fusion  Cortical bone trajectory screw  Osteoporosis  Prospective randomized controlled trail

English Abstract:

  【Abstract】 Objectives: To investigate the efficacies of cortical bone trajectory(CBT) screw fixation and pedicle screw(PS) fixation in the surgical treatment of lumbar degenerative diseases with osteoporosis and related complications. Methods: The sample size was estimated according to the non-inferiority test criteria. Approved by the ethics committee, we prospectively included 124 patients with lumbar degenerative disease from March 2019 to June 2020 and they were randomly assigned into the CBT group and PS group for single-level CBT screw fixation and PS fixation respectively for posterior lumbar decompression and fusion. The patients were followed up for at least 2 years. The primary endpoint was interbody fusion rate; secondary endpoints were visual analogue scale(VAS) for low back and lower extremity pain, Oswestry disability index (ODI), Janpanese Orthopedics Association(JOA) score at pre-operation, postoperative 3 months and 1-year and final follow up, and surgical parameters (operation duration, incision length, intraoperative blood loss, and postoperative drainage volume), as well as intraoperative and postoperative complications. The data of the two groups were compared between and within groups. Results: A total of 58 patients in the CBT group and 56 in the PS group completed follow-up. No significant differences were found between the two groups in terms of age, gender, follow-up period, smoking history, body mass index(BMI), bone mineral density(BMD) or surgical segment distribution(P>0.05). At 1-year post-operation, 45 patients (77.59%) in the CBT group and 42 (75.00%) in the PS group achieved interbody fusion, and there was no significant difference between the two groups(P=0.745). The VAS, ODI, and JOA score at postoperative 3 months, 1 year, and final follow-up of both groups improved significantly than those before operation(P<0.05); There was no significant difference in preoperative VAS, ODI, and JOA score between the two groups, and the ODI and JOA score of CBT group at postoperative 3 months were better than those of PS group(P<0.05); No statistical difference was found between the two groups in terms of postoperative 3 months, 1 year, and final follow-up VAS and postoperative 1 year and final follow-up ODI and JOA score(P>0.05). The operative time, intraoperative blood loss, incision length, and postoperative drainage volume of CBT group were all superior than those of PS group(P<0.05). The incidences of dural tear, nerve root injury, and surgical site infection were similar in both groups. Postoperative CT images showed screw misplacement rate was 2.16%(5/232) in CBT group and 1.34%(3/224) in PS group, and there was no statistical difference between groups(P=0.724). Two screws in CBT group occurred loosening and showed displacement on CT images, and the incidence rate was lower than that of PS group(10/224, 4.46%)(P=0.034). 3(5.17%) out of 58 patients of CBT group and 9(16.07%) out of 56 of PS group presented with complications, and the incidence rate of complications of PS group was higher(P=0.041). Conclusions: CBT screw fixation can achieve better short-term functional recovery than PS fixation in patients with osteoporotic lumbar degenerative disease undergoing single-level fixation and fusion, as well as similar clinical efficacy and interbody fusion. CBT screw fixation is an effective and superior alternative to PS fixation in the surgical treatment of lumbar degenerative disease patients with osteoporosis.