[EFFECTIVENESS EVALUATION OF PERCUTANEOUS MONOAXIAL SCREW COMBINED WITH INJURED VERTEBRAE POLYAXIAL PEDICAL SCREW FIXATION FOR TREATMENT OF THORACOLUMBAR FRACTURES].

Objective: To explore the effectiveness percutaneous monoaxial screw combined with polyaxial pedical screw for treating thoracolumbar fracture by comparing with simple polyaxial pedicle screw fixation.
Methods: Between January 2012 and June 2014, 56 cases of thoracolumbar fractures were treated by percutaneous pedicle screw fixation, the clinical data were retrospectively analyzed. Of 56 cases, 30 were treated with percutaneous monoaxial screw combined with percutaneous polyaxial pedical screw fixation (group A), 26 patients with only percutaneous polyaxial pedicle screw fixation (group B). There was no significant difference in gender, age, body mass index, injury causes, time from injury to admission, involved segments, fracture type, and preoperative American Spinal Injury Association (ASIA) stage, visual analogue scale (VAS), the anterior height of the injured vertebrae, Cobb angle, and sagittal index between 2 groups ( P >0.05). The operation time, intraoperative blood loss, and complications were recorded and compared between the 2 groups. The VAS score was used to evaluate the improvement of the pain. The sagittal kyphosis Cobb angle, the anterior height of the injured vertebrae, sagittal index, and the average correction (difference between 3 days after oeration and preoperation) and loss degrees (difference between last follow-up and 3 days after operation) were measured on the X-ray films at preoperation, 3 days after operation, and last follow-up.
Results: Incision healing at stage I was obtained, no related complications occurred. The operation time and intraoperative blood loss showed no significant difference between 2 groups ( P >0.05). The patients were followed up 20-42 months (mean, 32 months) in group A and 21-44 months (mean, 30 months) in group B. VAS score of group A was significantly lower than that of group B at 3 days after operation ( t =-2.277, P =0.027), but no significant difference was found at last follow-up ( t =-0.289, P =0.774). X-ray examination showed good position of internal fixation, with no broken nails or exit of nail. There were significant differences in the anterior height of the injured vertebrae, Cobb angle, and sagittal index between at preoperation and at 3 days and last follow-up, and between at 3 days and last follow-up in 2 groups ( P <0.05). The anterior height of the injured vertebrae, Cobb angle, and sagittal index of group A were significantly better than those of group B at 3 days and last follow-up ( P <0.05), and correction degree were significantly higher than those of group B ( P <0.05), but loss degree was not significant between 2 groups ( P >0.05).
Conclusions: Percutaneous monoaxial screw combined with polyaxial pedicle screw fixation is better than simply polyaxial pedicle screw in effects of treating thoracolumbar fracture under the premise of strictly holding indications.