Keywords
thoracolumbar fractures - long-segment fixation - inclusion of the fractured level
Key Messages
-
Thoracolumbar junction spine fractures present a dilemma for most spine surgeons.
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Short-segment fixation with inclusion of the fractured level provides good kyphosis
correction and restoration of vertebral body height that can be compared with those
of traditional long-segment fixation method.
Introduction
Thoracolumbar junction fractures are the most common fractures of the thoracolumbar
region[1] however, there is no definite guidelines for their management.[2] Currently, there are numerous surgical techniques for the treatment of these fractures
including anterior approach, posterior approach, minimally invasive and combined anterior
and posterior approach. As there is no clear guideline on the surgical technique to
be used for the treatment of each type of the thoracolumbar fractures, the choice
is falls on the surgeon. Moreover, the number of levels to be instrumented to achieve
adequate stability is also the surgeon's decision.[3]
Long-segment fixation was the traditional method for the management of unstable thoracolumbar
spine fractures. This was done by posterior fixation of two or more segments above
and below the fractured vertebra using transpedicular screws. Despite having low construct
failure rate and superior stability compared with other methods of fixation, recent
studies have reported adverse effects such as dorsalgia, implant failure, and significant
reduction of vertebral mobility due to loss of motion segments.[4]
Short-segment fixation including the fractured level was advocated by recent studies
to be a better choice than short-segment fixation alone as it prevents implant failure
of the short-segment fixation and achieves good results that are comparable to long-segment
fixation.[5]
[6]
In this study, we compared the results of short-segment fixation including fractured
level and those of long-segment fixation.
Patients and Methods
Data collected from records of patients with thoracolumbar junction fractures who
were operated at Neurosurgery Department, Qena University Hospital, South Valley University,
Qena, Egypt.
Patients selected for the study were 18 years or older, suffering from traumatic single
level thoracolumbar junction fracture with no or incomplete deficit, where computed
tomographic (CT) scans showed loss of vertebral body height less than 50% and retropulsed
fragment in spinal canal less than 50% of the sagittal canal diameter with intact
or unilateral fractured pedicles.
Those who had multiple spine fractures, presenting with paraplegia or with bilateral
fractured pedicles on CT scans, were excluded from the study.
Clinical evaluation was done by recording the neurological status of each patient
according to the American Spinal Injury Association (ASIA) classification score in
the preoperative and postoperative period.
Radiological evaluation was done using plain radiographs and CT scans of the spine
to determine the kyphotic angle by measurement of the Cobb angle (from the superior
endplate of the vertebra above the fracture level to the inferior endplate of the
vertebra below the fracture level), anterior and posterior vertebral body heights
and the vertebral body compression ratio of the fractured vertebra using the anterior/posterior
vertebral body compression ratio (APCR) method (AVBH/PVBHx100).
The anteroposterior spinal canal diameter at the maximum area of retropulsed bone
fragment was measured in each case, compared with the canal diameter of the adjacent
level and correlated with the degree of neurological deficit if present.
Patients were categorized in two groups, those who underwent long-segment fixation
(group A) and those who underwent short segment fixation including the fracture level
(group B). Both groups were compared with each other in terms of the radiological
parameters listed above.
Surgical Method
Standard posterior spinal approach was performed in all cases. In short-segment fixation
including fracture level, transpedicular screws were inserted in the normal vertebrae
just above and below the fractured vertebra under image guidance, then a transpedicular
screw was inserted in the fractured vertebra. In long-segment fixation, transpedicular
screws were inserted in the two normal vertebrae above and the two normal vertebrae
below the fracture level. Spinal canal decompression was done at the fracture level.
Connecting rods were placed on either side after precontouring them according to the
sagittal profile of the thoracic kyphosis and the lumbar lordosis and the bone graft
collected from decompression process was stuffed laterally to enhance lateral intertransverse
spinal fusion.
Outcome Evaluation
Clinical evaluation of the neurological status using the ASIA classification score.
Radiological evaluation of the Cobb angle, the vertebral body height, and the vertebral
body compression ratio was calculated on the CT scans done in the immediate postoperative
period.
Results
The study included 27 patients with thoracolumbar junction fractures. Group A included
27 patients (18 males and 9 females) and group B included 30 patients (21 males and
9 females). The mean age was similar in both groups ranging from 19 to 61 years in
group A and from 18 to 63 years in group B.
The majority of cases (39) were caused by fall from height followed by road traffic
accidents (12). Thirty-five patients had fracture L1, while L2 fractures occurred in 12 cases and D12 fractures were encountered in 10 cases.
Thirty-nine patients were neurologically intact (ASIA grade E), while the remaining
eighteen patients had incomplete neurological injury (13 ASIA grade D and 5 grade
C) ([Table 1]).
Table 1
Comparison between anteroposterior canal diameters according to ASIA classification
|
ASIA grade
|
Mean AP diameter at fracture level (mm)
|
Mean normal AP diameter at adjacent level (mm)
|
|
E
|
13.27
|
18.32
|
|
D
|
7.91
|
19.71
|
|
C
|
4.2
|
19.22
|
Abbreviations: AP, anteroposterior; ASIA, American Spinal Injury Association.
The mean preoperative Cobb angle was 22.51 degrees in group A and 19.37 degrees in
group B. Both groups showed improvement in the postoperative Cobb angle as the mean
in group A was 14.17 degrees and in group B 11.77 degrees.
Regarding the vertebral body compression ratio, the mean preoperative compression
ratio in group A was 82.8%, while in group B, it was 76%. The postoperative mean in
group A was 89.2%, while in group B it was 84%.
The mean preoperative anterior vertebral body height of the fractured vertebra in
group A was 16.7 mm, while in group B, it was 15.18 mm. The mean preoperative posterior
vertebral body height in group A was 16.33 mm and that of group B was 19.41 mm. The
mean postoperative anterior vertebral body height in group A was 17.66 mm and that
of group B was 17.10 mm. The mean postoperative posterior vertebral body height in
group A was 17.11 mm and that of group B was 20.79 mm ([Fig. 1]; [Table 2]).
Fig. 1 (A) Preoperative computed tomographic (CT), sagittal view, showing L1 # with measurement of Cobb angle, anterior vertebral body height (AVBH) and posterior
vertebral body height (PVBH). (B) Postoperative CT, sagittal view, showing screws in place and measurement of Cobb
angle, AVBH and PVBH.
Table 2
Comparison between group A and group B according to radiological parameters
|
Parameter
|
Group A
|
Group B
|
|
Preoperative
|
Postoperative
|
Preoperative
|
Postoperative
|
|
Cobb's angle (mean)
|
22.51 degrees
|
14.17 degrees
|
19.37 degrees
|
11.77 degrees
|
|
Anterior vertebral body height (mean)
|
16.7 mm
|
17.66 mm
|
15.18 mm
|
17.10 mm
|
|
Posterior vertebral body height (mean)
|
16.33 mm
|
17.11 mm
|
19.41 mm
|
20.79 mm
|
|
Vertebral body compression ratio (mean)
|
82.8%
|
89.2%
|
76%
|
84%
|
Discussion
The approach to thoracolumbar spine fracture management is still under much deliberation.
Stable fractures can be treated in a conservative manner by immobilization; however,
the same cannot be said in case of unstable fractures. These fractures—especially
those with retropulsed fragments—usually require surgical intervention to decompress
the neural element and perform internal fixation.[7]
Different surgical modalities have been proposed over the last century, many of which
are still in use to this moment. The most commonly used surgical approach is posterior
transpedicular screw fixation because it offers rigid fixation and requires less expertise
compared with anterior approach. Despite being very popular, there is still controversy
about how many levels should be included in the construct.[8]
Posterior long-segment fixation has been the traditional method for stabilizing the
fractured spine involved in the instrumentation of at least two vertebrae above and
two vertebrae below the fractured level deliver effective stabilization and minimize
the threat of posttraumatic kyphosis and implant breakage. However, this technique
has many disadvantages including extensive dissection, increased operative time, intraoperative
blood loss, and financial cost. It also results in a relevant reduction of the vertebral
motion.[5]
Posterior short-segment fixation with two additional screws at the fracture level
has been lately favored for the treatment of thoracolumbar spine unstable fractures
claiming that the adding of pedicle screws at the fractured vertebra can considerably
increase spinal stability, provide stronger fixation, and decrease the stress on the
pedicle screws in the nonfractured adjacent vertebra.[9]
In our study, we used data collected from records of 57 patients with thoracolumbar
junction fractures who were operated using both long-segment fixation and short-segment
fixation including the fracture level and compared the radiological outcome of both
groups in terms of kyphotic angle, vertebral body compression ratio, and the heights
of the anterior and posterior vertebral body.
To assess the relation between the canal diameter and the neurological state, we measured
the anteroposterior canal diameter of the fractured level for each patient with the
anteroposterior canal diameter of the adjacent vertebra and we found that the severity
of canal stenosis correlates to the severity of the neurological deficit in patients
with thoracolumbar spine fractures.
Both groups showed statistically significant improvement in Cobb's angle (p-value of group A = 0.004 and that of group B = 0.0002). Both groups showed improvement
in the postoperative measurements of the vertebral body compression ratio compared
with preoperative ones. However, group B was superior to group A showing 9.5% improvement
(p-value = 0.008) compared with 7.2% for group A (p-value = 0.05). We also found that group B showed better restoration of the anterior
and posterior vertebral body heights than group A. ([Fig. 2])
Fig. 2 (A) Preoperative computed tomographic (CT), sagittal view, showing D12 # with measurement of Cobb angle, anterior vertebral body height (AVBH) and posterior
vertebral body height (PVBH). (B) Postoperative plain radiograph, lateral view, showing screws in place and measurement
of Cobb angle, AVBH and PVBH. (C) Preoperative CT, axial view showing D12 # and measurement of anteroposterior canal diameter of D11 and D12.
By observing these results, we can endorse the posterior short-segment fixation with
inclusion of the fracture level for surgical stabilization of the thoracolumbar spine
junction as it showed better correction of the radiological parameters and similar—if
not better—biomechanical stability to posterior long-segment fixation.
Conclusion
Posterior short-segment fixation with additional screws at the fracture level provides
similar—if not better—radiological outcome to long-segment fixation in the treatment
of thoracolumbar junction fractures.
