From October 2008 to February 2011, our department used posterior percutaneous puncture hollow pedicle screws for internal fixation of spinal instability in patients with thoracolumbar fractures without neurological symptoms, with simple intraoperative operations and good immediate postoperative results. 1. Clinical data 1.1 General data 26 patients, 16 males and 10 females, aged 22-63 years old, average 42 years old. There were 7 cases of thoracic 11 and 12 fractures, 12 cases of lumbar 1 fractures, 5 cases of lumbar 2 fractures, and 2 cases of lumbar 3 fractures. The causes of injury: 13 cases of fall from height, including 2 cases combined with pelvic fracture, 2 cases combined with hemopneumothorax, 1 case combined with left radius fracture, 11 cases of car accident, including 2 cases combined with tibiofibular fracture, 2 cases combined with splenic rupture, and 2 other cases, all patients with Denis three-column typing were unstable fractures, and the indications for posterior repositioning and fixation surgery were clear. 1.2 Preoperative preparation All patients routinely underwent CT examination of the fractured vertebral body and MRI examination of the spine to understand the occupancy of the spinal canal and the damage to the spinal cord and posterior longitudinal ligaments before surgery. In patients with combined hemopneumothorax, closed chest drains were retained and removed after postoperative review of chest CT, while patients with combined other fractures underwent internal fixation with fracture dissection. 1.3 Surgical method The patient was routinely placed in the prone position with pillows on the chest and hip and the abdomen suspended, and was repositioned using the body position. Firstly, the patient was given approximate body surface positioning and four body surface positioning kerf pins were placed, the length of the kerf pins should be different from the top to the bottom and the left to the right to facilitate identification after fluoroscopy, the upper and lower vertebrae of the diseased vertebrae were fluoroscopically viewed, the body surface projection was marked, the lateral deflection was about 25px, the puncture was implanted on both sides at the same time. Fluoroscopy confirms that the puncture needle in the frontal position is located above and outside the “catenary”, and the puncture needle in the lateral position is located above the pedicle. The puncture needle is inserted into the anterior column of the vertebral body, the guide needle is implanted, the position of the guide needle is confirmed by fluoroscopy, the hollow screw of appropriate length is implanted, the repositioning is supported, and the repositioning of the diseased vertebra is confirmed by fluoroscopy, and the screw position is normal. Place the connecting rod and rinse and suture the subcutaneous skin. 1.4 Postoperative treatment In addition to symptomatic treatment, patients with combined fractures of other parts were given appropriate prolonged bed rest after surgery. Patients who did not combine other fractures started active exercise of the muscles of the limbs on the second postoperative day, and started to exercise the muscles of the low back in a tolerable state on the third postoperative day, and wore a thoracolumbar brace for functional exercise three weeks later. The brace was protected for 3 months. 1.5 Follow-up contents Routine postoperative X-ray films, visual analog pain scoring (VAS), dysfunction index (ODI), Cobb angle, etc. were used to assess the efficacy. 2. Results All patients successfully completed the surgical operation without complications such as incisional infection, nerve root or spinal cord injury. The mean operative time was (60±15) min, and the mean intraoperative bleeding was (85±10) ml. The follow-up time ranged from 28 months to 32 months, with a mean of 24 months, and the preoperative VAS score was (7.8±1.1) and the postoperative day 3 (2.0±0.6); the preoperative Cobb angle was (40.1°±3.5°) and the postoperative Cobb angle was (6.3±3.6, P<0.05). The postoperative ODI score was 8.0±0.6 at 1 month, and the postoperative anterior margin height and posterior convexity of the vertebral body were corrected. The internal fixation was removed at a mean of 14 months postoperatively, and no patient had internal fixation fracture. The x-ray Cobb angle was 7.8±1.4° with no significant loss of height on review after internal fixation removal, and the ODI score was 6.5±0.8 1 week after removal of internal fixation. Figure: Implantation of guide needle Puncture needle puncture 2 Start of surgery to locate the body puncture point using a kerfing needle 1 Start of surgery to locate the body puncture point using a kerfing needle (1) Female. 37y, lumbar 2 compression fracture, preoperative x-ray Fluoroscopy after implantation of pedicle screw Postoperative x-ray 1 year and 18 months after removal of internal fixation Postoperative x-ray 1 year after surgery Postoperative skin incision appearance Postoperative x-ray 3, Discussion 3.1 Spine surgeons often encounter cases of traumatic lumbar fracture in their clinical work, some patients have mild injury and no neurological symptoms, but the patient's imaging examination vertebrae have mild However, the treatment of such patients is relatively simple, but the conventional posterior open repositioning requires extensive stripping, as well as muscle stripping, but the postoperative presentation is often characterized by lumbar weakness and fatigue, and some patients are unable to perform heavy physical labor. Most scholars believe that this is due to damage to the posterior branch of the spinal nerve, resulting in atrophy of the innervation of the paravertebral muscles. In order to reduce this injury, many scholars at home and abroad have tried to use minimally invasive surgical methods to implant pedicle screws to achieve bracing, repositioning, and fixation in these patients and have achieved good results. Mathews, Lowery et al [4, 5] were the first to apply such techniques for the treatment of thoracolumbar fractures and pointed out that these techniques have the advantages of small incision, less intraoperative and postoperative bleeding, and less damage to the muscles of the lumbar back. In China, Zhou Yue and Chi Yonglong; were the first to apply and promote this type of technique in clinical practice. In 2005, our department studied the anatomical characteristics of percutaneous pedicle nail fixation on the basis of cadaveric anatomy, and selected some cases for successful treatment of thoracolumbar fractures using percutaneous puncture technique and a large number of clinical applications, with the development of internal fixation devices, the application of this type of technique was raised to a new level. The traditional percutaneous puncture technique does not allow the placement of guide pins because the pedicle screws are solid, the muscle tissue around the opening needs to be cleared to reveal the pedicle entrance when screwing in the screws, and the screwing process may lead to the wrong approach of the screws, which requires the use of a revealing device or an auxiliary access system. In addition, the screws cannot be operated bilaterally, and each time the screws are inserted, the position of the pedicle screws needs to be determined by frontal and lateral fluoroscopy, which exposes both the operator and the patient to dozens of times. The simultaneous operation of the hollow pedicle screw bilaterally not only saves operative time but also requires only a few C-arm irradiations for both the operator and the patient. The maximum time for this group of patients was 75 minutes in the early stage, but only 30 minutes was needed to complete the operation, and the number of fluoroscopies was also significantly reduced, requiring only a few fluoroscopies in the body surface positioning - the puncture needle in the forward and lateral position - the guide needle implantation - the pedicle screw implantation - and the understanding of the reset situation after bracing and repositioning. It also reduces the number of exposures for the patient. At the same time, it reduces bleeding and soft tissue damage and does not reduce the effect of repositioning, as illustrated by the Cobb angle of (45.1°±3.5°) before surgery and (6.3±3.6 P<0.05) after surgery in this group. 3.2 Indications for percutaneous posterior percutaneous puncture hollow pedicle screw internal fixation for thoracolumbar fractures, pedicle puncture considerations Clinically, there are different criteria for judging the indications for surgery for thoracolumbar fractures at home and abroad, such as TLICS is a total score from the mechanism of injury, the degree of nerve or spinal cord involvement, and the integrity of the posterior spinal complex, with less than 3 points considered conservative treatment, surgery equal to 4 points can be conservative or surgery, and a score greater than or equal to 5 requires surgical treatment. The Denis staging suggests unstable fractures in patients with mid-column involvement and the need to restore spinal stability to avoid reducing possible long-term complications. In our patients, the TLICS staging system suggested a score greater than 4, and the Denis staging indicated the presence of combined anterior, middle, and posterior column injuries, with indications for surgery. However, for patients treated with percutaneous posterior puncture hollow pedicle screw internal fixation of the thoracolumbar spine because of the small incision, the spinal canal needs to be decompressed, especially for patients with combined nerve root or spinal cord injury, CT and MRI suggesting compression in the spinal canal exceeding 30% of the spinal canal, patients with damage to the posterior longitudinal ligament, and patients with combined severe osteoporosis are not suitable for this surgical approach. ①The choice of the puncture point, which is usually chosen outside or above the "catenary" of the vertebral arch, is crucial to the success of the procedure. ③After puncture into the vertebral body, the lateral fluoroscopy reaches the anterior column of the vertebral body, and the fluoroscopy reveals that the puncture needle has crossed the median line of the spinous process, the possibility of rupture of the inner wall of the pedicle is high, and the puncture angle needs to be readjusted, and the screw should not be screwed in to avoid damage to the spinal cord or nerve roots ④The appropriate length of pedicle screw is selected according to the need during puncture, and the length of the screw should avoid being too short, generally it needs to reach the anterior column of the vertebral body and cross the midline of the vertebral body on the lateral film The length of the screws should avoid being too short, generally reaching the anterior column of the vertebral body and the midline of the vertebral body on the lateral film, reaching the anterior-posterior junction, but should also avoid being too long to avoid penetrating the anterior edge of the vertebral body and damaging the anterior vessels and organs.