Cement-augmented sacral screw in lumbosacral degenerative disease with osteoporosis

English Keywords:Sacral screw  Cement augmentation  Osteoporosis  Lumbosacral degenerative disease

English Abstract:

  【Abstract】 Objectives: To evaluate the outcomes of cement-augmented sacral screw in lumbosacral degenerative disease with osteoporosis. Methods: From May 2012 to December 2015, 61 patients with bone mineral density T score of -3.37±0.69 SD(-2.5 to -5.4 SD), who underwent posterior lumbosacral fixation with pedicle screws were enrolled, including six males and fifty-five females, aging from 60-80 years(67.5±6.6 years) old. All patients received cement-augmented pedicle screw fixation at L5, and they were divided into 3 groups according to fixation patterns of S1 pedicle screws, bone cement augmentation group(group A, 17 cases), bicortical pedicle screw group(group B, 20 cases) and three cortical pedicle screw group(group C, 24 cases). The visual analogue scale(VAS) and Oswestry disability index(ODI) before surgery and at the final follow-up were assessed. Besides, the operative complication, screw loosening rate and bone fusion rate were also recorded. Results: All the surgeries were successful, and patients were followed up for 19.98±10.42 months(24-78 months). The VAS and ODI scores at the final follow-up significantly improved from the scores before surgery in all groups. In addition, group A had the lowest VAS and ODI scores at final follow-up when compared to the other two groups, and no significant difference was detected between group B and C(P＞0.05). In group A, the rate of bone cement leakage in lumbar and sacrum was 23.68% and 23.53%, respectively, other complications included dural tear(1 case), shallow wound infection(1 case) and lateral plantar flexion weakness(1 case), with no screw loosening and fusion failure. In group B, the rate of bone cement leakage was 41.25%, the rate of S1 screw loosening was 30%, with 2 cases of contralateral limb numbness and weakness. In group C, the rate of bone cement leakage was 24.46%, the rate of S1 screw loosening was 25%, with 2 cases of dural tear, 1 case of wound infection, 1 case of contralateral limb numbness and weakness. Furthermore, old age, long fusion segment and large post-op PI-LL were found as the risk factors of S1 screw loosening without cement-augmentation, rather than gender, BMD, BMI, surgical approach, pre and post-operative LL, SS, PT, PI, or the change of LL, pre-operative PI-LL(P>0.05). Conclusions: Sacral screw cement augmentation is able to achieve optimistic stability with less screw loosening in lumbosacral degenerative disease with osteoporosis, which is especially recommended in patients with old age, two or more segments fixation and large post-operation PI-LL.