Biblioteca Virtual en Salud

Objective To explore what cause the screw loosening after the internal fixation with thoracic and lumbar pedicle screws in the elderly and to develop the preventive measures.Methods Retrospective analysis were used to collect the clinical data from patients ager 60 years and over who had undergone surgeries of thoracolumbar pedicle screw internal fixation in our hospital during May 2011 and May 2013.Totally 187 cases were included in this study.According to whether there was a loosening of the screws, patients were divided into fixtion-loose and-well groups.The operation time and blood loss volume in the two groups were recorded.Visual analogue scale (VAS), Oswestry disability index (ODI), the rate of screw loosening were compared at 6 months after operation and the last follow-up.The causes of screw loosening were analyzed.Results The main causes for the thoracic and lumbar pedicle screw internal fixation were thoracolumbar kyphoscoliosis, fractures,spondylolisthesis, cancer and degenerative diseases, etc.Patients were followed up for an average of (35.2±8.7) months.13 patients (7.0％) were found screw loosening, 5 males and 8 females, with the mean age of (78.4 ± 3.5) years.The screw loosening occurred 3 months to 1 year after the surgery, (7.6±3.7) months on average.Among the 13 patients with screw loosening, 1 patient suffered screw loosening in single segment, 3 patients in two segments, and 9 patients in three segments or above.Osteoporosis combined with screw loosening.appeared in 10 patients VAS and ODI scores in all subjects had statistically differences at 6 months after operation and the last follow up versus preoperation (P＜0.05 for all), but no statistical difference versus the last follow-up(P＞ 0.05).There were significant differences in gender and preoperative osteoporosis rate between the two groups (P＜0.05 for both).Conclusions Osteoporosis is one of the reasons for the screw loosening in elderly patients after pedicle screw internal fixation.The increased probability of the screw loosening in long segment may be related with the change of the older spine mechanics.Further randomized controlled trials are still required to confirm whether elderly osteoporosis patients need to receive bone cement augmentation treatment.