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 Table of Contents  
STUDY PROTOCOL
Year : 2016  |  Volume : 1  |  Issue : 4  |  Page : 152-157

Posterior percutaneous pedicle screw fixation for acute thoracolumbar vertebral fractures with simple anterior spinal column injury: study protocol for a retrospective, self-controlled trial


Department of Spine Surgery, Orthopedic Trauma Center, PLA 153 Central Hospital, Zhengzhou, Henan Province, China

Date of Web Publication30-Nov-2016

Correspondence Address:
Wen-de Liu
Department of Spine Surgery, Orthopedic Trauma Center, PLA 153 Central Hospital, Zhengzhou, Henan Province
China
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2542-4157.194807

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  Abstract 

Background: Posterior pedicle screw fixation is commonly used for thoracolumbar fracture. However, associated disadvantages include severe trauma, extensive bleeding, long rehabilitation time, and long postoperative duration of intractable lumbar stiffness and low back pain. Percutaneous pedicle screw external fixation can reduce injury caused by screw insertion into the paraspinal muscles; particularly in acute thoracolumbar vertebral compression fracture with simple anterior spinal column injury. We hypothesized that minimally invasive posterior percutaneous pedicle screw fixation for acute thoracolumbar vertebral fractures with simple anterior spinal column injury would exhibit good curative effects.
Methods/Design: This retrospective, single-center, self-controlled trial was performed in the PLA 153 Central Hospital, Zhengzhou, Henan Province, China. Thirty-two patients with acute thoracolumbar vertebral fracture with simple anterior spinal column injury (22 males and 10 females, average age 24.7 years, range 25-47 years) were included. All patients underwent minimally invasive posterior percutaneous pedicle screw internal fixation and were followed up for 3 months. The primary outcome measure was the Cobb angle of the injured vertebral body before, immediately after, and 3 months after internal fixation, which was used to investigate the change in the thoracolumbar spine curvature. The secondary outcome measures included: the anterior height of the injured vertebral body and radiographic findings before and immediately after internal fixation and at the last follow-up (to evaluate the recovery of thoracolumbar vertebral fracture), operation time, intraoperative blood loss, and duration of hospitalization. Other outcome measure was the incidence of adverse events 3 months after internal fixation.
Discussion: This study aims to validate the curative effects of minimally invasive posterior percutaneous pedicle screw fixation in acute thoracolumbar vertebral fractures with simple anterior spinal column injury, and provide objective long-term follow-up data for future studies.
Trial registration: ClinicalTrials.gov identifier: NCT02963571.
Ethics: The study protocol had been approved by the Ethics Committee of PLA 153 Central Hospital, China and was performed in strict accordance with the Declaration of Helsinki developed by the World Medical Association.
Informed consent: Written informed consent regarding study protocol and treatments had been obtained from each patient.

Keywords: clinical trial; thoracolumbar vertebral fractures; minimally invasive; pedicle screw; anterior spinal column injury; Cobb angle; X-ray; adverse events; self-controlled trial


How to cite this article:
Liang L, Liu Wd, Wu Yf, Sun Xh, Ding Jj. Posterior percutaneous pedicle screw fixation for acute thoracolumbar vertebral fractures with simple anterior spinal column injury: study protocol for a retrospective, self-controlled trial. Clin Trials Orthop Disord 2016;1:152-7

How to cite this URL:
Liang L, Liu Wd, Wu Yf, Sun Xh, Ding Jj. Posterior percutaneous pedicle screw fixation for acute thoracolumbar vertebral fractures with simple anterior spinal column injury: study protocol for a retrospective, self-controlled trial. Clin Trials Orthop Disord [serial online] 2016 [cited 2019 Jul 23];1:152-7. Available from: http://www.clinicalto.com/text.asp?2016/1/4/152/194807


  Introduction Top


History and current related studies

Thoracolumbar spinal fractures are frequently seen after trauma because of the biomechanical transitional junction of this structure (Pradhan and Pandey, 2015; Khatri et al., 2016; Saffarzadeh et al., 2016; Soliman et al., 2016). The primary treatment method used for traumatic thoracolumbar spinal fracture is posterior pedicle screw fixation, but this method has some disadvantages including severe trauma, extensive bleeding, long rehabilitation time, and long postoperative duration of intractable lumbar stiffness and low back pain (Ni et al., 2010; Li et al., 2013). These complications occur mainly because of wide stripping and injury of the paraspinal muscles and peri-articular denervation. Percutaneous pedicle screw external fixation of spine fracture can reduce injury caused by screw insertion into the paraspinal muscles (Magerl, 1982), particularly in the treatment of acute thoracolumbar vertebral compression fracture with simple anterior spinal column injury (Gu et al., 2013, 2015).

Main objectives

We combined posterior pedicle screw internal fixation with percutaneous pedicle screw fixation to validate the safety and effectiveness of minimally invasive posterior percutaneous pedicle screw fixation in acute thoracolumbar vertebral fractures with simple anterior spinal column injury.

Distinguishing features from related studies

Previous studies investigating repair of acute thoracolumbar vertebral fractures with simple anterior spinal column injury have mainly used simple posterior or percutaneous pedicle screw fixation. In this study, we will use a combination of these two methods to treat acute thoracolumbar vertebral fracture with simple anterior spinal column injury, in an attempt to achieve better curative effects compared with monotherapy.


  Methods/Design Top


Study design

A retrospective, single-center, self-controlled trial.

Study setting

Department of Spine Surgery, Orthopedic Trauma Center, PLA 153 Central Hospital, Zhengzhou, Henan Province, China.

Study procedures

We retrospectively analyzed the clinical data of 32 patients with acute thoracolumbar vertebral fractures with simple anterior spinal column injury who underwent minimally invasive posterior percutaneous pedicle screw fixation in the Orthopedic Trauma Center, PLA 153 Central Hospital, China and were followed up for 3 months.

The Cobb angle, the anterior height and the morphologic data of the injured vertebral body before, immediately after, and 3 months after surgery were determined on radiographs. In addition, operation time, intraoperative blood loss, duration of hospitalization, and the incidence of adverse events were recorded to comprehensively evaluate the effectiveness and safety of minimally invasive posterior percutaneous pedicle screw fixation in acute thoracolumbar vertebral fractures with simple anterior spinal column injury. A flow chart of the study protocol is shown in [Figure 1].
Figure 1: Flow chart of trial protocol.

Click here to view


Inclusion criteria

Patients of either sex with all of the following conditions were considered for study inclusion:

  • Meet the diagnostic criteria of acute thoracolumbar vertebral fracture with simple anterior spinal column injury as confirmed by radiography, CT and MRI
  • AO classification type A
  • Thoracolumbar injury severity score of 4-5 (Park et al., 2016)
  • Traumatic fracture
  • Age 25-47 years


Exclusion criteria

Patients with any one or more of the following were excluded:

  • Fracture complicated by spinal cord injury
  • Fracture complicated by nerve injury
  • Refusal to provide informed consent


Baseline evaluation

The baseline information including demographic data and general disease history of the included patients is shown in [Table 1].
Table 1: Baseline data of included patients

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Sample size

In accordance with our experience, we hypothesized that the Cobb angle of the injured vertebral body at postoperative 3 years will be narrowed by 65% compared with before surgery. Taking β = 0.1 and power = 90% with a significance level of α = 0.05 (two-sided), the final effective sample size of n = 67 per group was calculated using PASS 11.0 software. Assuming a patient loss rate of 20%, we require 81 patients per group. According to the inclusion and exclusion criteria, we included 32 patients in each group.

Recruitment

We collected the clinical data of patients with acute thoracolumbar vertebral fractures with simple anterior spinal column injury who received treatment between August 2010 and June 2014 in the Orthopedic Trauma Center, PLA 153 Central Hospital, China. According to inclusion and exclusion criteria, suitable patients or their relatives were contacted via telephone. After acquiring informed consent, the clinical data recorded during hospitalization were analyzed.

Blinding

This is an open-label trial. Patients, physicians and assessors were not blinded to group information and therapeutic regimen.

Interventions

  • Preoperative preparation


After induction of general anesthesia via endotracheal intubation, patients were placed in a prone position with the abdomen suspended in the air. The lumbar spine was appropriately adjusted, and the injured vertebral body was reduced in vitro.

  • Location of the injured vertebral body


C-arm fluoroscopy was used to scan the targeted vertebral body in the anteroposterior view at the axial plane of the vertebral arch, and the projective points of the injured superior and inferior vertebral bodies on the vertebral arch were marked.

  • Minimally invasive posterior percutaneous pedicle screw fixation


After sterilization, longitudinal incisions of 1.5-2.0 cm were made slightly lateral to the four marked points until the subcutaneous fascia was visualized and hemostasis was performed. An acupuncture needle was inserted into the targeted vertebral arch; the acupuncture needle was not passed through the inner wall of the vertebral arch in the sagittal plane, and was kept parallel to the upper and lower endplates in the horizontal plane. A guide pin was inserted along the acupuncture needle, and then the acupuncture needle was withdrawn. Using the guide pin, a pedicle screw (Beijing Fule Science & Technology Development Co., Ltd., China; titanium alloy; State Food and Drug Administration Permission Number: 2010-3460133) was inserted. A connective bar of appropriate length was placed and the bolt was tightened. A distraction and compression tool was used for appropriate collection, compression, and fixation. After position confirmation by X-ray fluoroscopy, wounds were flushed and sutured without drainage. Postoperatively, prophylactic antibiotic treatment was administered for 24-48 hours.

  • Notes on internal fixation


○ Effective in vitro reduction: A surgical bed waist bridge was used to adjust the patients' posture, and the anterior height of the injured vertebral body was partially recovered to minimize poor reduction caused by poor longitudinal distraction.

○ The preoperative bony structure, pedicle arch width and axial length were precisely measured on radiographs and CT images to reduce the required number of fluorescence examinations and facilitate precise and rapid selection of screw diameter and length.

○ Precise location on the body surface: During the surgery, the targeted vertebral body was imaged at the axial plane of the pedicle arch ( i.e., the upper and lower endplates were in one straight line), avoiding the error of pedicle arch projection.

○ Precise screw insertion in the targeted vertebral body: The needle insertion point and incisions were located slightly away from the exterior margin of the location on the body surface, in an attempt to eliminate the sagittal angle of needle insertion and the elastic binding of the skin edge and avoid medial insertion of the needle.

○ Maintenance of consistent orientation of the U-shaped gutter of the upper and lower nails was important to ensure the successful insertion of the connective bar and reduce unnecessary nail adjustment.

Outcome measures

Primary outcome measure


The Cobb angle of the injured vertebral body before, immediately after, and 3 months after internal fixation was measured to investigate the change in the thoracolumbar spine curvature. A greater Cobb angle indicates more severe kyphosis (Jiang et al., 2012).

Secondary outcome measures

  • Anterior height of the injured vertebral body before, immediately after, and 3 months after surgery was measured to evaluate the morphological recovery of the thoracolumbar spine. A smaller anterior height of the injured vertebral body indicates less severe injury to the vertebral body.
  • Morphological data of the injured vertebral body on radiographs taken before, immediately after, and 3 months after surgery
  • Operation time
  • Intraoperative blood loss
  • Duration of hospitalization


Other outcome measure

Incidence of adverse events. Postoperative complications were evaluated at the last follow-up examination, which was conducted 3 months after surgery.

The schedule of outcome measurement assessments is shown in [Table 2].
Table 2: Timing of outcome assessment

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Adverse events

We recorded possible adverse events, including wound pain, infection, back muscle pain, spinal cord/nerve injury, screw pull-out, or screw loosening. If severe adverse events occurred, details including the data of occurrence and measures taken to treat the adverse events were reported to the principle investigator and the institutional review board within 24 hours.

Possible biases and management measures

Possible biases

  • Diagnosis bias
  • Admission rate bias (hospitalized patients were preferred to reduce loss to follow-up and to increase compliance)
  • No response bias (subjects not responding to the questionnaire or not responding truthfully)
  • Mixed bias (sex and age)


Measures taken to control possible biases

  • Formulation of strict inclusion and exclusion criteria
  • Ensuring sample independence
  • Discussion of the mixed factors that may potentially influence the curative effects, such as pathological factors, course of disease, and sex


Statistical analysis

Statistical analysis was performed by a statistician using SPSS 19.0 software (IBM, Amrok, USA), and was conducted following the intention-to-treat principle. Normally distributed measurement data were expressed as the mean ± SD, and minimums and maximums. Non-normally distributed measurement data were expressed as lower quartile (q1), and median and upper quartile (q3). The Wilcoxon matched-pairs signed-ranks test was performed for comparison of the Cobb angle before surgery with the Cobb angle 3 years after surgery, and the McNemar's chi-squared test was used to compare the incidence of adverse reactions. The significance level was α = 0.05.


  Trial Status Top


The whole study had been completed at the time of manuscript submission. Thirty-two patients were followed up for 3 months. The study outcomes are as follows: Average operation time was 95 minutes (range 60-120 minutes), average intraoperative blood loss was 75 mL (range 50-90 mL), and average wound length was 1.8 cm (range 1.5-2.0 cm). Patients wore a thoracolumbar spine brace for out-of-bed activities for 1-2 weeks postoperatively, and average duration of hospitalization was 8 days (range 4-12 days).

Postoperatively, no patient experienced obvious wound pain, wound nonunion, or injury of the spinal cord or nerves. Minimally invasive posterior percutaneous pedicle screw fixation resulted in a small wound, minimal bleeding, and rapid rehabilitation.

The anterior height and Cobb angle of the injured vertebral body were significantly improved at 3 months postoperatively compared with before surgery (P < 0.05; [Table 3], [Figure 2]).
Figure 2: Representative images of anterior height and Cobb angle of the injured vertebral body of a 46-year-old male with L1 compression fracture (AO classification type A).
Note: (a) Before surgery. (b) Immediately after surgery. (c) 3 months after surgery. The anterior height and Cobb angle of the injured vertebral body were obviously improved at 3 months after surgery compared with before surgery.


Click here to view
Table 3: Imaging data before and after minimally invasive posterior percutaneous pedicle screw fixation for acute thoracolumbar vertebral fractures with simple anterior spinal column injury

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Back muscle pain occurred in 1 of 32 patients (3%) at postoperative 4 weeks. The pain resolved after 2-4 weeks of conservative treatment. No other adverse events were observed in any patient throughout the 3 month follow-up period.

In conclusion, minimally invasive posterior percutaneous pedicle screw fixation for the repair of acute thoracolumbar vertebral fractures with simple anterior spinal column injury exhibits safe and reliable curative effects.


  Discussion Top


Significance of this study

This study aims to validate that minimally invasive posterior percutaneous pedicle screw fixation for acute thoracolumbar vertebral fractures with simple anterior spinal column injury exhibits good curative effects, which can compensate for the disadvantages including a relatively large wound, extensive bleeding and long rehabilitation time.

Limitations of this study

The outcome measures are very simple and stratification exists. These are confounding factors that may influence study outcomes. As this is a retrospective study, case selection bias and information collection bias may exist, and may influence the reliability of the outcomes.

Evidence for contribution to future studies

This study aims to validate the safe and reliable curative effects of minimally invasive posterior percutaneous pedicle screw fixation in acute thoracolumbar vertebral fractures with simple anterior spinal column injury, contributing to clinical promotion of this surgical internal fixation technique.[11]

 
  References Top

1.
Gu Y, Zhang F, Jiang X, Jia L, McGuire R (2013) Minimally invasive pedicle screw fixation combined with percutaneous vertebroplasty in the surgical treatment of thoracolumbar osteoporosis fracture. J Neurosurg Spine 18:634-640.   Back to cited text no. 1
    
2.
Gu YT, Zhu DH, Liu HF, Zhang F, McGuire R (2015) Minimally invasive pedicle screw fixation combined with percutaneous vertebroplasty for preventing secondary fracture after vertebroplasty. J Orthop Surg Res 10:31.   Back to cited text no. 2
    
3.
Jiang SD, Wu QZ, Lan SH, Dai LY (2012) Reliability of the measurement of thoracolumbar burst fracture kyphosis with Cobb angle, Gardner angle, and sagittal index. Arch Orthop Trauma Surg 132:221-225.  Back to cited text no. 3
    
4.
Khatri K, Farooque K, Sharma V, Gupta B, Gamanagatti S (2016) Neglected thoracolumbar traumatic spine injuries. Asian Spine J 10:678-684.   Back to cited text no. 4
    
5.
Li Z, Zhu TB, Zhang Y, Zhao AB, Lv XF, Ren J, Liu F (2013) Percutaneous pedicle screw fixation in the treatment of thoracolumbar fractures. Zhongguo Gu yu Guanjie Sunshang Zazhi 28:851-852.  Back to cited text no. 5
    
6.
Magerl F (1982) External skeletal fixation of the lower thoracic and the lumbar spine. Current concepts of external fixation of fractures. New York: Spring Verlag.  Back to cited text no. 6
    
7.
Ni WF, Huang YX, Chi YL, Xu HZ, Lin Y, Wang XY, Huang QS, Mao FM (2010) Percutaneous pedicle screw fixation for neurologic intact thoracolumbar burst fractures. J Spinal Disord Tech 23:530-537.   Back to cited text no. 7
    
8.
Park HJ, Lee SY, Park NH, Shin HG, Chung EC, Rho MH, Kim MS, Kwon HJ (2016) Modified thoracolumbar injury classification and severity score (TLICS) and its clinical usefulness. Acta Radiol 57:74-81.  Back to cited text no. 8
    
9.
Pradhan RL, Pandey BK (2015) Does tranexamic acid reduce perioperative bleeding in short segment pedicle screw fixation in thoracolumbar spine fractures? JNMA J Nepal Med Assoc 53:169-173.  Back to cited text no. 9
    
10.
Saffarzadeh M, Hightower RC, Talton JW, Miller AN, Stitzel JD, Weaver AA (2016) Multicenter analysis of CIREN occupant lumbar bone mineral density and correlation with age and fracture incidence. Traffic Inj Prev 17 Suppl 1:34-41.  Back to cited text no. 10
    
11.
Soliman HM, Nguyen HS, Banerjee A, Pintar F, Yoganandan N, Kurpad S, Maiman D (2016) Changing threshold for AIS scores of thoracolumbar compression fractures. Traffic Inj Prev 17 Suppl 1:11-15.  Back to cited text no. 11
    

Declaration of patient consent
The authors certified that they had obtained all appropriate patient consent forms. In the form the patient(s) gave his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understood that their names and initials would not be published and due efforts were made to conceal their identity, but anonymity would not be guaranteed.
Conflicts of interest
None declared.
Author contributions
LL conceived and designed this protocol, wrote the paper. WDL, YFW, XHS and JJD assisted in trial conduction. All authors read and agreed the final version of this paper for publication.
Plagiarism check
This paper was screened twice using CrossCheck to verify originality before publication.
Peer review
This paper was double-blinded and stringently reviewed by international expert reviewers.


    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1], [Table 2], [Table 3]



 

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