Keywords
traumatic thoracolumbar fracture - spinal injuries - three-column fixation - transpedicular
corpectomy - posterior only approach
Introduction
Thoracolumbar fracture is most common because it is uniquely positioned between rigid
thoracic spine and mobile lumbar spine. Most authors agreed for surgical management
of unstable thoracolumbar fracture, but choice of approach is still a matter of debate.
Traditional posterior approach is preferred because of less complication rate and
less complexity of surgery. Posterior approach has disadvantage of insufficient spinal
canal decompression, less stable construct, and more chances of recurrent kyphosis.
To overcome these disadvantages, anterior approach and later on combined anteroposterior
approaches were developed. Access to thoracolumbar vertebral bodies or discs via traditional
transthoracic or retroperitoneal approaches carries significant morbidity.[1]
[2] Additional posterior stabilization or decompression is often required, thus further
increasing the risks of the operation.[3]
[4] Single-stage three-column fixation through posterior approach has been described
in an attempt to simplify the surgical approach for circumferential decompression
and simultaneous stabilization of the thoracolumbar spine.[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13] Many studies were done to compare anterior approach and combined anteroposterior
approach with posterior approach but no study was done to compare combined anteroposterior
decompression and stabilization through posterior only approach versus traditional
posterior approach.
In the present study, we attempt to compare single stage three-column fixation through
posterior approach with traditional posterior approach in terms of surgical, neurological,
and functional outcome.
Method
Patients
This is retrospective study comprising 47 patients of traumatic thoracolumbar fracture
admitted between September 2016 and January 2018 in neurosurgery ward of Dr. Ram Manohar
Lohia Institute of Medical Sciences, Lucknow. Inclusion criteria include patients
who were adult and diagnosed as a case of unstable thoracolumbar fracture, underwent
either single stage three-column fixation through posterior approach or traditional
posterior approach. Posterior approach includes short-segment fixation including fracture
segment (SSF IFS) and long-segment fixation (LSF). Patients were undergone either
of surgery depending on implant availability in the operating room.
Preoperative Assessment
Fracture was classified according to modified AO classification. Neurological assessment
of all patients was done with ASIA impairment scale, assessment of pain was done with
visual analogue scale (VAS), functional assessment was done with lower extremities
functional score, and kyphosis was measured with Cobb's angle.
Operative Procedure
In the single-stage three-column fixation through posterior approach, under general
anesthesia and prone position, midline longitudinal incision was taken. Bilateral
facia and muscle were dissected till transverse process one level above and below
the fracture segment. The lamina of the fractured vertebrae and the lamina of the
cranial vertebrae were removed to expose the pedicles of the fractured vertebrae.
Discectomies were performed one level above and one level below the fractured vertebrae
to expose the end plates. The pedicles of the fractured vertebrae were exposed completely.
Unilateral or bilateral pedicular resection was achieved based on anterior compression.
We routinely performed only one side pedicular resection as optimum anterior decompression
and cage placement can be achieved unilaterally. Through the resected pedicle, the
posterior two-thirds of the fractured vertebra were totally removed with a high-speed
drill and hand curettes. To protect the dura while drilling, a thin layer of cortex
was left posteriorly which was broken with curved curette later on. Anterior decompression
of the dura was achieved. Superior and inferior disc spaces were cleared with curved
hand curettes and end plates prepared. Anterior part of the fractured vertebrae was
kept intact, but a space for putting expandable cage was formed within the fractured
vertebrae. Pedicular screws were introduced into the upper and lower vertebrae and
distraction was applied to assist the entrance of the expandable cage. The expandable
cage, filled with autologous bone graft, was inserted into the fractured vertebrae
through the resected pedicle. The nerve root exiting through the inferior foramen
was protected during placement of the cage. Cage was distracted so that it settles
optimally on the end plates. The distraction of the cage was guided by preoperative
anteroposterior and lateral fluoroscopic image. Finally, pedicular screws were loosened
and fixed again in compression. The autologous cancellous bone chips were embedded
over the decorticated posterolateral gutter to augment fusion ([Figs. 1]
[2]).
Fig. 1 (A) Posterior laminectomy with transpedicular anterior decompression of cord with placement
of pedicle screw and opposite side rod fixation. Posterolateral gutter is made for
distractable cage. (B) Distractable cage is placed.
Fig. 2 Combined decompression and stabilization through posterior only approach: (A) Preoperative magnetic resonance imaging, (B) preoperative X-ray, and (C) postoperative X-ray.
For traditional pedicle screw fixation, pedicle screw was placed one level above and
one level below including fracture segment and posterior decompression was done in
SSF IFS method ([Fig. 3]). In LSF method, pedicle screw was placed two levels above and two levels below
the fracture segment ([Fig. 4]).
Fig. 3 Short-segment fixation including fracture segment (SSF IFS): (A) Preoperative magnetic resonance imaging, (B) preoperative X-ray, and (C) postoperative SSF IFS.
Fig. 4 Posterior approach long-segment fixation (LSF): (A) Preoperative magnetic resonance imaging, (B) preoperative X-ray, and (C) postoperative LSF.
Duration of surgery, intraoperative average blood loss is noted in each surgery.
Follow-Up
All patients were discharged on seventh day after stich removal. Postop X-ray at 1
week and 3 months was done. Postoperatively, AIS, VAS, LEFS, and kyphotic angle was
noted in all patients at seventh day and 3 months. To decrease bias in neurological
and functional assessment, parameters were not measured in immediate postoperative
days.
Data Analysis
Patient data were analyzed using STATA-12 Software. Unaired student t-test and Kruskal–Wallis nonparametric test were used for statistical analysis.
Results
Three patients had injury due to fall from height, while 17 patients had road traffic
accident ([Table 1]). Out of 47 patients, 33 patients were operated through traditional posterior approach
and 13 patients were operated through single stage three-column fixation through posterior
only approach. In traditional approach, 21 patients were operated using SSF IFS method
and 12 patients were operated using LSF.
Table 1
Patient-related parameters
|
No of patient (%)
|
|
Abbreviations: FFH, fall from height; RTA, road traffic accident.
|
|
Age (in years)
|
|
10–20
|
10 (21.3)
|
|
20–30
|
10 (21.3)
|
|
30–40
|
8 (17.0)
|
|
40–50
|
7 (14.9)
|
|
>50
|
12 (25.5
|
|
Sex
|
|
Male (M)
|
40 (85.1)
|
|
Female (F)
|
7 (14.9)
|
|
# Level
|
|
D11
|
1 (2.1)
|
|
D12
|
19 (40.43)
|
|
D12, L1
|
2 (4.26)
|
|
L1
|
22 (46.81)
|
|
L2
|
3 (6.4)
|
|
Mode of injury
|
|
FFH
|
30 (63.81)
|
|
RTA
|
17 (36.81)
|
|
Type of # (AO classification)
|
|
A3
|
10 (21.28)
|
|
A4
|
21 (44.7)
|
|
B2
|
4 (8.6)
|
|
B3
|
6 (12.8)
|
|
C
|
6 (12.8)
|
The mean age of patients treated through traditional approach is 38 ± 2.6 (standard
deviation [SD]) years, whereas it is 32.9 ± 3.0 (SD) years in single-stage three-column
fixation approach (combined). Out of 33 patients, those operated with traditional
approach, 30 patients are male and 3 patients are female, whereas out of 14 patients
operated with combined approach, 10 patients are male and 4 patients are female ([Table 2]). Overall L1 vertebrae fracture is most common in our study ([Table 1]). In traditional approach, most commonly patient with L1 fracture is operated, that
is, 17 out of 33 patients, whereas patient with D12 level fracture is most commonly
operated with three-column fixation approach, that is, 7 out of 14 patients ([Table 2]). Most common fracture type is AO class A4 in both approaches followed by AO class
A3 in traditional approach and AO class B3 and C in combined approach ([Table 2]).
Table 2
Patient-related parameters according to surgical approach
|
Characteristics
|
Surgical approach
|
p-Value
|
|
Traditional
|
Combined
|
|
Abbreviations: AO, Association for the Study of Internal Fixation; SE, standard error
|
|
Mean age ± SE (in years)
|
41.0 ± 2.6 years
|
22.9 ± 3.0 years
|
p < 0.001
|
|
Sex (M/F)
|
M = 30, F = 3
|
M = 10, F = 4
|
p = 0.086
|
|
Fracture level
|
|
D11
|
1
|
0
|
|
|
D12
|
12
|
7
|
|
|
D12, L1
|
2
|
0
|
|
|
L1
|
17
|
5
|
|
|
L2
|
1
|
2
|
|
|
Fracture type (AO class)
|
|
A3
|
10
|
0
|
|
|
A4
|
12
|
9
|
|
|
B2
|
3
|
1
|
|
|
B3
|
4
|
2
|
|
|
C
|
4
|
2
|
|
Changes in neurological and functional status of in two groups were compared at preoperative
state, 1 week and 3 months postoperatively ([Table 3]). The median change in AIS score at third month observed in traditional approach
is 1 (IQR 0.1) and that observed in combined approach is 1.04 (interquartile range
[IQR] 0.1). This difference was found to be statistically nonsignificant (p = 0.991). (Kruskal–Wallis test nonparametric test) The median change in LEFS score
at third month observed in traditional approach is 34 (IQR 22.46) and that observed
in combined approach is 38 (IQR 32.50) ([Table 3]). This difference was found to be statistically nonsignificant (p = 0.561) (Kruskal–Wallis test nonparametric test).
Table 3
Changes in neurological and functional outcome
|
Preoperative
|
Postoperative at 1 week
|
Postoperative at 3 Months
|
|
Traditional
|
Combined
|
Traditional
|
Combined
|
Traditional
|
Combined
|
|
Abbreviations: AIS, Asia Impairment Scale; ASIA, American Spinal Injury Association;
LEFS, Lower Extremity Functional Scale.
|
|
AIS (ASIA impairment scale)
|
|
A
|
2
|
0
|
1
|
0
|
2
|
1
|
|
B
|
10
|
7
|
7
|
5
|
4
|
2
|
|
C
|
6
|
4
|
10
|
5
|
5
|
4
|
|
D
|
14
|
3
|
14
|
4
|
13
|
6
|
|
E
|
1
|
0
|
1
|
0
|
9
|
1
|
|
VAS
|
|
1–3 (mild pain)
|
0
|
0
|
26
|
12
|
33
|
14
|
|
3–7 (moderate pain)
|
1
|
0
|
7
|
2
|
0
|
0
|
|
7–10 (severe pain)
|
32
|
14
|
0
|
0
|
0
|
0
|
|
LEFS (changes in score)
|
|
<10
|
|
|
10
|
6
|
2
|
1
|
|
10–20
|
|
|
18
|
4
|
4
|
2
|
|
20–30
|
|
|
5
|
4
|
8
|
0
|
|
30–40
|
|
|
0
|
0
|
7
|
6
|
|
>40
|
|
|
0
|
0
|
12
|
5
|
The mean VAS score at third month in subjects treated with traditional approach was
1.8 ± 0.61 whereas in subjects treated with combined approach the mean VAS score was
1 ± 0.39 ([Table 4]). The difference in VAS scores observed at third month was found to be statistically
significant (p < 0.001).
Table 4
VAS score and Kyphosis correction observed at 3 months after surgery
|
Traditional posterior
|
Combined posterior only
|
p-Value
|
|
Abbreviations: SD, standard deviation; VAS, visual analogue scale.
|
|
VAS score (mean ± SD)
|
1.85 ± 0.61
|
1.0 ± 0.39
|
0.0001
|
|
Kyphotic correction at 3 months in degree (mean ± SD)
|
11.73 ± 3.60
|
15.36 ± 4.25
|
0.0045
|
In traditional surgeries, there was an observed correction of 11.73° ± 3.6° in kyphosis,
while in combined surgeries the observed correction in kyphosis was 15.36° ± 4.25°
([Table 4]). This difference was found to be statistically significant (p = 0.004) (unpaired student t-test).
In traditional approach, there was an observed average blood loss of 108 ± 27.32 mL,
while in combined approach the observed average blood loss was 263 ± 40.84 mL ([Table 5]). This difference was found to be statistically significant (p = 0.001).
Table 5
Average blood loss and duration of surgery
|
Traditional posterior
|
Combined posterior only
|
p-Value
|
|
Blood loss
|
108 ± 27.32 mL
|
263 ± 40.84 mL
|
0.0001
|
|
Duration of surgery
|
120.3 ± 25.43 minutes
|
150 ± 13.01 minutes
|
0.0002
|
Likewise, in traditional approach, there was an observed duration of surgery 120.3
± 25.43 minutes, while in combined approach the observed duration of surgery was 150
± 13.01 minutes ([Table 5]). This difference was found to be statistically significant (p = 0.002).
Intraoperatively, dural tear was found in two patients which was repaired successfully.
No other complications related to operative site infection or implant failure were
reported in immediate postop period and at 3 months follow-up.
Discussion
The approach which gives maximum benefit to the patient of traumatic thoracolumbar
fracture is still the matter of debate. Several research article and meta-analysis
were published, but no study favors one over other. Few studies were done for comparing
combined approach versus posterior approach. Till date no study was done to compare
combined anteroposterior decompression with stabilization through posterior only approach
versus traditional posterior decompression with stabilization.[14]
[15]
[16]
[17]
[18]
A meta-analysis was done by Oprel et al to compare combined anteroposterior surgery
versus posterior surgery for thoracolumbar fractures to identify better treatment.[18] They concluded that a small significantly higher kyphotic correction and improvement
in vertebral height observed for the combined anteroposterior group is cancelled out
by more blood loss, longer operation time, longer hospital stay, higher costs, and
a possible higher intra- and postoperative complication rate requiring reoperation.
The surgeons’ choices regarding the operative approach are biased: worse cases tended
to undergo the combined anteroposterior approach.
A prospective multicenter study done by Knop et al and a retrospective study done
by Been and Bouma to compare combined approach versus posterior approach show similar
results.[15]
[19] In these studies, combined method showed comparative high blood loss, longer operation
time, longer hospital stay, higher costs, and a possible higher intra-and postoperative
complication rate because of anterior approach. In our study, these complications
and morbidity mostly associated with anterior approach are not found because combined
decompression and stabilization were done through posterior only approach.
Our study shows kyphosis correction at 3 months is more in three-column fixation than
traditional posterior approach. It shows that on 3-month follow-up examination, loss
of correction is smaller in three-column fixation than traditional posterior approach
as seen in previous studies on anterior and combined approach. Four case series on
combined decompression and stabilization through posterior only approaches in patients
of traumatic thoracolumbar fracture concluded that significant correction in kyphosis
and nonsignificant loss of kyphotic correction.[10]
[11]
[12]
[13]
Postoperatively, pain on VAS score was significantly improved in both approaches,
but it is significantly reduced in combined decompression through posterior only approach
at 3 months than traditional posterior approach.
Our study showed that both traditional posterior approach and combined decompression
and stabilizations through posterior only approach were equally effective when the
neurological (AIS), functional (LEFS) parameters were compared. There were no differences
in the neurological or functional outcome as concluded in other studies.
We found lower blood loss and shorter operation time in traditional posterior approach
surgery than the three-column fixation through posterior only approach. This is expected
because of additional procedure in the combined approach.
Anterior neurodecompression still remains the practice in many institutions, as experimental
data have shown that early neurodecompression is crucial for regeneration of nerve
tissue.[9] Our results showed that the choice of three-column fixation through posterior only
approach or posterior approach for decompression did not influence the neurological
or functional outcome; however, neurological and functional improvements were seen
in each patient. This might be because more severely injured and higher AIS grade
patients tend to get operated through combined decompression method thorough posterior
only approach.
The limitations of the study were the relatively small study size and unusual allocation
of the patients into groups. Patients were divided into two trial groups according
to the implants available in the operating theater at the time of the patient's admission.
The lack of funds was the reason why implants for combined surgery (expandable cage)
were rarely available. On the other hand, these circumstances favor traditional posterior
approach fixation, which is preferred technique in our institution.
The next step should be a prospective randomized controlled trial of longer follow-up
with proper supply of needed implants.
Conclusion
Combined anteroposterior decompression and stabilization through posterior only approach
is convenient for complete decompression of cord, stabilization, and restoration of
vertebral height, and there is statistically significant kyphotic correction, pain
relief (VAS) but there is no statistically significant neurological and functional
outcome than traditional posterior approach. Most neurosurgeons are familiar to posterior
approach; hence, it should be used in unstable thoracolumbar fracture whenever needed,
while avoiding various dreaded complication of combined approach.
