Elsevier

Journal of Clinical Neuroscience

Volume 72, February 2020, Pages 219-223
Journal of Clinical Neuroscience

Clinical study
Anterior versus posterior approach in the management of AO Type B1 & B2 traumatic thoracolumbar fractures: A level 1 trauma centre study

https://doi.org/10.1016/j.jocn.2019.11.039Get rights and content

Highlights

  • First study on surgical approaches in flexion-distraction thoracolumbar fractures.

  • Ideal approach in AO Type B1/B2 thoracolumbar fractures is controversial.

  • At 6 months, there is a trend toward improvement in ≥1 AIS grade in posterior group.

  • Posterior approach resulted in better Cobb angle correction at follow up.

  • Results to be interpreted with caution due to inherent selection bias in study.

Abstract

The authors perform a retrospective trauma registry study to compare clinical, surgical and radiographical variables between anterior and posterior approaches in the management of AO Type B1 and B2 traumatic thoracolumbar fractures. Consecutive patients with surgically-managed AO Type B1 and B2 thoracolumbar fractures were included. Baseline demographics, surgical outcomes (including duration of surgery, postoperative morbidity etc.), neurological outcomes and radiographical outcomes (Cobb angle, Gardner angle) were compared between the anterior and posterior approaches. A total of 108 patients (anterior: n = 25, posterior: n = 83) were included. There were no significant between-group differences in baseline demographics and co-morbidities. Duration of surgery was longer in the anterior compared to posterior group (251 ± 91 min vs. 175 ± 69 min respectively, p < 0.00003). At six-months post-surgery, there was a trend towards improvement of at least one AIS grade in the posterior compared to the anterior group (85.7% vs. 33.3% respectively, p = 0.08). Postoperative complication profile showed no difference between approaches. The posterior approach resulted in better sagittal correction (Cobb angle; anterior: +1.05 ± 8.61 deg, posterior: −3.87 ± 9.88 deg, p = 0.03) and smaller loss of correction at 6-months post-surgery (Cobb angle; anterior: 8.36 ± 9.47 deg, posterior: 4.88 ± 6.62 deg, p = 0.048). This is the first study investigating surgical approach in flexion-distraction thoracolumbar fractures. Besides a shorter operative duration, the posterior approach seems to portend more favourable radiological correction at 6 months when compared to the anterior approach. Given the inherent selection bias of this study, definitive recommendations regarding the anterior versus posterior approach cannot be made. Further well-defined, prospective studies are necessary.

Introduction

AO Type B1 and B2 thoracolumbar fractures are posterior tension band injuries [1]. Type B1 fractures are the classic Chance fractures denoting monosegmental, trans-osseous injury. Type B2 fractures are osteoligamentous or ligamentous-only posterior tension band injuries. Type B1 and B2 flexion distraction injuries are regarded as unstable injuries for which surgical management is generally recommended [2]. The AOSpine classification standardizes fracture-patient description and facilitates systematic study of individual fracture types.

Surgical stabilization of thoracolumbar fractures can be performed via standalone anterior, posterior or combined anterior-posterior approaches. The posterior approach is versatile, reliable, and familiar for spine surgeons. The anterior approach allows for vertebral body reconstruction and direct spinal canal decompression. However, each approach has its attendant disadvantages, with increased morbidity [3] demonstrated in some studies for the anterior approach, and inadequate sagittal deformity correction [4], [5] shown in posterior approaches.

In preparation for this study, a systematic review was undertaken. To the authors’ knowledge, there exists no study specifically comparing surgical approaches in flexion distraction thoracolumbar fractures (including Denis, Magerl and AOSpine classifications). The majority of such studies pertain to “burst” fractures [6], [7], [8], which are morphologically and biomechanically different from flexion distraction fractures. In this novel study, the authors compare clinical, surgical and radiographical metrics between anterior and posterior approaches in the management of AO Type B1 and B2 traumatic thoracolumbar fractures.

Section snippets

Methods

A retrospective registry query of a state-service Level 1 trauma service was undertaken between January 2008 and December 2017. Consecutive patients who met the following criteria were included: 1) adult patient ≥18 years old, 2) AO Type B1 or B2 traumatic thoracolumbar fracture from T9 – L2, 3) underwent surgical management from an anterior or posterior approach. We excluded patients with pathological fractures, and patients who underwent combined anterior-posterior approaches. Fracture

Results

A total of 108 patients (anterior approach: n = 25, posterior approach: n = 83) were included. There were 40 Type B1 fractures and 68 Type B2 fractures, with no difference in the proportion of Type B1 and B2 fractures between anterior and posterior groups (Type B1: anterior = 32.0%, posterior = 38.6%, p = 0.72). The commonest levels of injury of Type B1 fractures is at T12 (40.0%) and L1 (42.5%), whilst that of Type B2 fractures is at T11-T12 (29.4%) and T12-L1 (47.1%) (Table 1). There were no

Discussion

This novel study compares the outcomes of the anterior and posterior approach on Type B1 and B2 flexion distraction thoracolumbar fractures. In this study, there was a trend toward improvement in AIS grade at six-months after surgery in the posterior group (when considering patients who were AIS A-D preoperatively). This result has to be interpreted with caution. Firstly, around half of patients who were eligible for this analysis had to have their data censored as their 6-month AIS grade were

Limitations

There are several limitations in this study. Firstly, as part of the study’s design, we did not include patients who had undergone combined anterior-posterior approaches. Thus, we cannot provide any information of how a combined approach will fare in comparison to the posterior (or anterior) approach. That was done as we felt that the inclusion would cloud our research question and also by the inclination of most spine surgeons to rely upon a standalone, single-stage approach for Type B1 and B2

Conclusion

This is the first study comparing surgical approach in flexion-distraction thoracolumbar fractures. Besides a shorter operative duration, the posterior approach seems to portend more favourable radiological correction when compared to the anterior approach. Given the inherent selection bias of this study, definitive recommendations regarding the anterior versus posterior approach cannot be made. Further well-defined, prospective studies are necessary.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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  • Risk Factors for Postoperative Complications After Surgical Treatment of Type B and C Injuries of the Thoracolumbar Spine

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    A recent systematic review that compared the anterior-posterior approach versus the posterior-only approach failed to identify any superiority of the combined approach in terms of clinical, radiologic, or functional outcomes, while there was a trend toward increased operative time, blood loss, and length of hospital stay with the combined approach.26 When comparing an anterior-only versus posterior-only approach treating type B fractures, superiority of the latter has been demonstrated, especially with radiologic outcomes, with similar complication rates with the 2 approaches.27 In addition, the popularity of minimallyinvasive spine surgery is growing and gaining a role in thoracolumbar spinal trauma, thanks to better operative outcomes and significant decreases in some complications like infection rate.28

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