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

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

Official Title
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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

Conditions
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Posterior Short-segment Pedicle Instrumentation

Intervention / Treatment
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* Device: fractured level screws-distraction


Participation Criteria
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Eligibility Criteria
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Inclusion criteria 18 years of age or above. single thoracolumbar burst fractures AO type A3 or A4 fractures Thoracolumbar Injury Classification and Severity Score (TLICS) of more than 4 and duration of < 2 weeks 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

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Screw-Distraction (SD) group<br>six pedicle screws were implanted firstly, then distraction was achieved. | Device: fractured level screws-distraction<br>* four pedicle screws were implanted into the upper vertebra and the lower vertebral body of the fractured vertebra. Then, immediate reduction and decompression were achieved by applying distraction of rod. Finally, two additional screws were introduced at fracture level<br>|
| Experimental: Distraction-Screw (DS) group<br>four pedicle screws were implanted firstly, then distraction was achieved, two additional screws were introduced at the fracture level at last. | Device: fractured level screws-distraction<br>* four pedicle screws were implanted into the upper vertebra and the lower vertebral body of the fractured vertebra. Then, immediate reduction and decompression were achieved by applying distraction of rod. Finally, two additional screws were introduced at fracture level<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| compression ratio change of anterior border of vertebral body height | using X-ray fluorescence | preoperatively, intraoperatively, on day 3 postoperatively and then at 1, 3, 6, 12 and 24 months postoperatively | 
| Depth of nail into injured vertebrae | using X-ray fluorescence | at postoperation immediately | 
| Kyphosis (Cobb) angle change | using X-ray fluorescence | preoperatively, intraoperatively, on day 3 postoperatively and then at 1, 3, 6, 12 and 24 months postoperatively | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Operative time | Unit of Measure is hour | right after surgery | 
| intraoperative blood loss | Unit of Measure is ml | right after surgery | 
| Complications | Pedicle fractures, intraoperative pars fractures, postoperative infection, deep venous thrombosis, nerve injury, and any other direct or indirect surgical complications will be recorded. | at postoperation immediately, 1, 3 and 6 months, and at 1 and 2 years postoperatively. | 
| pain degree of back and lower limb | The pain degree of back and lower limb during follow-up will be assessed by the VAS of back pain and VAS of leg pain | preoperatively, on day 3 postoperatively and then at 1, 3, 6, 12 and 24 months postoperatively. | 
| Oswestry Disability Index (ODI) change | The Oswestry Disability Index (ODI) will be asssessed by questionnaire | preoperatively, on day 3 postoperatively and then at 1, 3, 6, 12 and 24 months postoperatively | 
| The Japanese Orthopaedic Association (JOA) scores | Functional improvement is expressed by the rate of recovery of the JOA scores | preoperatively and postoperatively including day 3 and then 1, 3, 6, 12 and 24 months | 
| The American Spinal Injury Association (ASIA) impairment scale | Spinal Injury was assessed using ASIA | preoperatively, on day 3 postoperatively and then at 1, 3, 6, 12 and 24 months postoperatively |