Comparison of Unilateral and Bilateral Polymethylmethacrylate-augmented Cannulated Pedicle Screw Fixation for Management of Lumbar Spondylolisthesis with Osteoporosis

Abstract

Background: Many studies have shown that cannulated pedicle screw (CPS) augmented by polymethylmethacrylate (PMMA) can obtain a satisfactory clinical efficacy in the treatment of lumbar spondylolisthesis with osteoporosis. However, accurate application of CPSs will help to avoid the difficulty of screw revision and reduce the incidence of PMMA related complications. This study aims to investigate the mid-term efficacy of CPS comparing unilateral and bilateral application in this common lumbar degenerative disease. Methods: Between May 2011 and May 2018, 50 patients with posterior fixation and fusion using traditional pedicle screw or CPSs for lumbar spondylolisthesis with osteoporosis were included in the study. Patients were divided into 2 groups: those with unilateral PMMA-augmented CPSs (group UC n=29) and those with bilateral PMMA-augmented CPSs (group BC, n=21). Operation time, blood loss, average hospitalization time, PMMA leakage and other complications were recorded. Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) scores were used to evaluate the recovery of symptoms. Radiographic results were compared for the intervertebral fusion and screw loosening. Results: There were no significant differences in the baseline data of the 2 groups.VAS and ODI scores were improved significantly after surgery (P<0.05), with no differences between the groups (P>0.05). The operation time and blood loss in group UC were significantly lower than those in groups BC (P<0.05). However, the loss of intervertebral disc height and Taillard index had no difference in group UC compared with group BC. And the rates of PMMA leakage in group UC and BC were 7.0% and 11.9%, respectively (P<0.05). Bony fusion was achieved in all groups without screw loosening at the last follow-up. And only one patient experienced superficial infection in both groups, meanwhile two patients of cerebrospinal fluid leakage was observed in group BC.Conclusions: Unilateral application of PMMA-augmented CPS may provide adequate clinical safety and effectiveness in surgical treatment of lumbar spondylolisthesis with osteoporosis.