A Modified Placement of Two Additional Pedicle Screws at the Fracture Level for the Treatment of Thoracolumbar Burst Fractures--a Study Protocol of a Randomised Controlled Trial

A Modified Placement of Two Additional Pedicle Screws at the Fracture Level for the Treatment of Thoracolumbar Burst Fractures--a Study Protocol of a Randomised Controlled Trial

Controversies exist about the best treatment of burst fractures of the thoracolumbar spine. Adding screws in fractured segment has been proved in many literatures that can improve construct stiffness but sometimes aggravate the trauma of fractured vertebra. Therefore, we are eager to find an optimized placement of two additional pedicle screws at the fracture level for the treatment of thoracolumbar burst fractures. This is the first randomised controlled study investigating efficacy of diverse orders of pedicle screws placement and will provide recommendations for treating patients with thoracolumbar burst fractures.

A blinded randomised controlled trial (blinding for the patient and statistician, rather than for the clinician and researcher) will be conducted. A total of seventy patients with single thoracolumbar AO type A3 or A4 fractures who are candidates for application of short-segment pedicle screws of fractured vertebrae will be randomly allocated to either the DS group (distraction-screws ) or the SD group (screws-distraction) at a ratio of 1: 1. The primary clinical outcome measures are compression ratio of anterior border of vertebral body height, depth of nail into injured vertebrae and kyphosis (Cobb) angle. Secondary clinical outcome measures are complications, Visual Analogue Scale (VAS) of back and leg pain, neurological function, operating time, intraoperative blood loss, Japanese Orthopaedic Association (JOA) scores and Oswestry Disability Index. These parameters will be evaluated preoperatively, intraoperatively, on day 3 postoperatively and then at 1, 3, 6, 12 and 24 months postoperatively.

Inclusion criteria

1. 18 years of age or above.
2. single thoracolumbar burst fractures
3. AO type A3 or A4 fractures
4. Thoracolumbar Injury Classification and Severity Score (TLICS) of more than 4 and duration of < 2 weeks
5. application of posterior short-segment pedicle screws instrumentation at the fracture level Exclusion criteria

1. previous pedicle instrumentation at the same level 2. multi-segmental thoracolumbar fractures or not AO type A3 or A4 are found 3. pregnancy 4. active infection or surgical site of the previous infection 5. planned emigration abroad within 2 years after inclusion 6. suffering from illness or long-term use of certain drugs affecting the stability of the spinal environment, such as metabolic bone disease, spinal tuberculosis and so on 7. the current use of anticoagulant (such as warfarin) or postoperative heparin for more than 6 months