Percutaneous Screw Fixation vs. Open Fixation in the Treatment of Thoracolumbar Fractures

Thoracolumbar (TL) fractures occur in 8-15% of blunt trauma patients cared for in major trauma centers. These fractures can be devastating and commonly occur in patients who endure high-energy trauma (e.g. motor vehicle accidents). TL fractures occur mainly between T10 and L2. The "3 Column Model" attempts to identify criteria that can predict instability of TL fractures. This model divides the spine into anterior, middle, and posterior areas. Stability is dependent on the integrity of two out of three of the columns. Major spine injuries are those that involve mechanical or neurologic instability.

The four major types of injury include compression, burst, seat-belt, and fracture-dislocation. Compression fractures account for 50-70% of all TL fractures and usually consist of compression failure of the anterior column. Burst fractures comprise approximately 14% of all TL injuries. These injuries usually involve compression of both the anterior and posterior column. Seat-belt fractures (aka flexion-distraction fractures) account for 10% of TL injuries and occur most commonly in patients who are wearing only the lap belt (i.e. no chest belt) during motor vehicle trauma. These injuries typically involve compression of the anterior column with distraction failure of both the middle and posterior columns. Finally, the fracture-dislocation type fracture occurs with massive direct trauma to the back, causing failure of all three columns and translational injury.

Patients with TL fractures may present with TL spine pain, midline TL spine tenderness, TL spine bony deformity, or neurologic deficit. Oftentimes these patients were in high-velocity traumatic scenarios, including falls from heights, crush injuries, motor vehicle crashes with ejection, unenclosed vehicles (ex. motorcycles), or automobile versus pedestrian accidents. Diagnosis is confirmed via computed tomography (CT) imaging or plain radiographs. CT imaging is typically more accurate than plain radiographs but can be poor in certain subtypes of injury. MRI can be utilized to assess the integrity of the ligaments and surrounding soft tissues.

There is currently no universally accepted system for classifying the severity of TL fractures. One proposed system is the Thoracolumbar injury classification and severity score (TLICS). Points are awarded based on radiographic findings, neurologic status, and the integrity of posterior ligamentous complex. The final numeric score is used to guide treatment, with higher scores indicating need for surgery. Neurologic deficit favors surgery.

There is no clear consensus on the best treatment approach for TL fractures. For situations where conservative management is decided (i.e. surgery is not required or is contraindicated), patients are treated with recumbency and delayed ambulation in orthosis with serial radiographs to determine need for further intervention. The surgical management for more severe/unstable fractures usually involves posterior instrumentation with percutaneous or open pedicle screw fixation.3 While the traditional open pedicle screw fixation technique has demonstrated good radiologic and clinical outcomes, a minimally invasive percutaneous approach has been increasingly used in recent years. The minimally invasive technique potentially carries the advantage of less operative blood loss, shorter operative time, smaller incisions, potentially less postoperative pain, and overall shorter hospital stay. There are a few studies published in the literature, but more studies are needed to establish the treatment modality that is the most efficacious and safe for these patients.

At the University of Texas Southwestern (Parkland Hospital), the investigators evaluate and treat a large population of patients with TL fractures. Previous trials in the literature comparing open and percutaneous fixation of TL fractures have been series of ~100-200 patients. These studies have shown variable results, with many concluding similar outcome results for the two surgical techniques. The purpose of this study is to compare a larger number of patients (~500) who have undergone either surgical approach to determine the best technique in terms of clinical and radiographic outcomes. The investigators believe this study will provide neurosurgeons with invaluable information about the safety and efficacy of different treatment modalities for TL fractures in this patient population.