Treatment of A3 thoracolumbar vertebral burst fractures with posterior minimally invasive channels and short tail pedicle screw fixation: technical report and efficacy analysis
Authors: wu fujun , ju songli , Hou Genyi , Ao Jun , Huang Nijiao , Ye Sheng , Wang Xin 
Published: March 2020

Abstract
Background To evaluate the clinical efficacy of common pedicle screw placement combined with pedicle screw fixation for the treatment of thoracolumbar burst fractures using a posterior minimally invasive approach. Methods Between May 2015 and December 2016, a total of 33 cases of thoracolumbar burst fracture (AO/Magerl type A3) were treated using a posterior minimally invasive procedure with ordinary pedicle screws under the channel in combination with injured vertebra transpedicular fixations. The patient cohort included 20 males and 13 females with an average age of 43.5 yr (range: 26～61 yr). 16 cases were due to traffic accidents, whereas 11 cases were due to falls, and 6 cases of other injuries. All patients showed no nerve injury. Of the injured segments, 5 cases were T 11 , 14 were T 12 , 13 were L 1 , and one was L 2 .No patients presented with spinal nerve injury. The duration of the operations and intraoperative blood loss in each patient were recorded. The pain visual analogue scale (VAS) was used to estimate the degree of back -surgical incision pain. Measurements of the percentage of injured vertebral height loss and the sagittal Cobb angle, which was evaluated for correction of the kyphosis angle and height restoration using plain radiographs, Every patient were recorded preoperatively and at postoperative day 3, 6 month, 1 year, and final follow-up visits. Plain CT scans and reconstructions were used to assess fracture healing. Results No patients experienced intraoperative complications. The average operating time was 109.2 min (range: 90～130 min), and the average intraoperative blood loss was 82.4 ml (range: 50～150 ml). The VAS scores for the lumbar back incision on the 3rd postoperative day and at the final follow-up were 2.39 ± 0.83 points and 0.70 ± 0.68 points, respectively.Additionally, all incisions healed without any postoperative complications. All patients were followed up over a period of 13 to 24 months postoperatively (average 15.9 months). Compared to preoperative values, every patient in the percentage of vertebral height loss and the sagittal Cobb angle significantly improved over the follow-up period, with significant differences between day 3, 6 month, 1 year, and final follow-up visits (P<0.05). However, the difference was not significant between the groups at all postoperative time points (P>0.05). CT scans showed that the injured vertebrae healed well, with no subsidence, loosening, or fractures of the internal fixation. Conclusion The minimally invasive posterior approach with common pedicle screw placements and combined pedicle screw fixation is similar to percutaneous minimally invasive screw fixation. The pedicle screw rests on a strong internal fixation to restore and maintain vertebral height. This procedure is safe and effective for the treatment of A3 thoracolumbar burst fractures, resulting in less trauma and bleeding as well as satisfactory deformity correction.