Rating Quality of Evidence

The guideline task force used a modified version of the North American Spine Society’s evidence-based guideline development methodology. The North American Spine Society methodology uses standardized levels of evidence (Appendix III) and grades of recommendation (Appendix IV) to assist practitioners in easily understanding the strength of the evidence and recommendations within the guidelines. The levels of evidence range from level I (high quality randomized controlled trial) to level IV (case series). Grades of recommendation indicate the strength of the recommendations made in the guideline based on the quality of the literature. Levels of evidence have specific criteria and are assigned to studies before developing recommendations. Recommendations are then graded based upon the level of evidence. To better understand how levels of evidence inform the grades of recommendation and the standard nomenclature used within the recommendations, see Appendix IV.

Guideline recommendations were written using a standard language that indicates the strength of the recommendation. “A” recommendations indicate a test or intervention is 2 “recommended”; “B” recommendations “suggest” a test or intervention; “C” recommendations indicate a test or intervention or “is an option.” “Insufficient evidence” statements clearly indicate that “there is insufficient evidence to make a recommendation for or against” a test or intervention. Task force consensus statements clearly state that “in the absence of reliable evidence, it is the task force’s opinion that” a test or intervention may be considered. Both the levels of evidence assigned to each study and the grades of each recommendation were arrived at by consensus of the workgroup employing up to three rounds of voting when necessary.

In evaluating studies as to levels of evidence for this guideline, the study design was interpreted as establishing only a potential level of evidence. As an example, a therapeutic study designed as a randomized controlled trial would be considered a potential level I study. The study would then be further analyzed as to how well the study design was implemented and significant shortcomings in the execution of the study would be used to downgrade the levels of evidence for the study’s conclusions (see Appendix V for additional information and criteria).

Revision Plans

In accordance with the Institute of Medicine’s standards for developing clinical practice guidelines and criteria specified by the National Guideline Clearinghouse, the task force will monitor related publications after the release of this document and will revise the entire document and/or specific sections “if new evidence shows that a recommended intervention causes previously unknown substantial harm; that a new intervention is significantly superior to a previously recommended intervention from an efficacy or harms perspective; or that a recommendation can be applied to new populations.”¹ In addition, the task force will confirm within 5 years from the date of publication that the content reflects current clinical practice and the available technologies for the evaluation and treatment for patients with thoracolumbar trauma.

DISCUSSION

Eleven studies were identified as either cohort or randomized clinical trials that compared anterior, posterior, or combined anterior-posterior approaches (see Appendix VI). There were 4 randomized controlled trials that were rated as level II.^2-5 All 6 retrospective cohort studies were rated as level III.^6-10 One prospective cohort study was rated a level III.¹¹

Ten studies included only thoracolumbar burst fractures and 1 only included fracture dislocations.² Neurologic injuries varied among the studies with 8 studies including patients with deficits and 3 studies including patients without neurologic deficits.

The anterior approach included corpectomy or partial corpectomy, and reconstruction with strut grafting or cage and anterior instrumentation. If additional posterior instrumentation was used, then the patient was considered to be a combined anterior-posterior approach. The posterior group used pedicle screws except in 2 studies where posterior rod-hook instrumentation was performed. Posterior decompression may have been performed as needed in this group. In addition, 2 studies that used transforaminal interbody decompression and fusion (TLIF) combined with posterior pedicle screw instrumentation were included in the posterior approach group.^2,11 The authors could not stratify the results in patients having posterior decompression and instrumentation to posterior instrumentation only. Combined anterior-posterior approach included corpectomy or partial corpectomy, and reconstruction with strut grafting or cage and anterior instrumentation and additional posterior pedicle screw instrumentation.

Seven studies compared anterior to posterior approach: 2 studies were level II, and 5 were level III (see Appendix VI). Five studies compared posterior to combined anterior-posterior approaches, 3 of which were level II and 2 were level III. One study had 3 treatment arms and was included in both the comparisons between anterior and posterior and between posterior and combined approaches.⁷ There was no literature available to compare anterior only to combined anterior-posterior approach.

Comparison of Anterior versus Posterior Approaches

Clinical Outcomes

There were 7 studies that compared clinical and neurologic outcomes of anterior decompression and fusion to posterior surgery with or without decompression (Table 1). No differences in neurologic outcomes or clinical outcomes were noted in any study.

Radiologic Outcomes

Two studies showed better overall fracture Cobb angle correction at final follow-up with anterior surgery, while 5 studies reported no differences in radiologic outcomes between anterior and posterior approaches. The 2 studies that favored anterior surgery were both level III evidence, while 2 level II and 3 level III studies did not show a difference.

Complications

Complications were reported in 5 studies comparing anterior to posterior surgery. One level II study demonstrated fewer complications and favored the anterior approach, and 1 level II study favored the posterior approach. Three level III studies showed no differences between approaches.

Comparison of Posterior versus Anterior-Posterior Approach

Five studies compared posterior instrumentation with or without decompression to combined anterior-posterior approaches (Table 2). Two studies were level II randomized controlled trials, 2 studies were level III retrospective cohort study, and 1 study was a level III prospective cohort study.

Clinical Outcomes

Four studies (1 level II and 3 level III) reported no difference in clinical outcomes. One level II study reported better clinical outcomes in the posterior approach, although, despite lower pain, the authors recommended against the posterior only approach because of a high incidence of poor radiologic results. ⁵

Radiologic Outcomes

One level II and 2 level III studies reported no difference in radiologic outcomes between groups, while 1 level II study and 1 level III favored the anterior-posterior approach.

Complications

Complications occurred more frequently after anterior-posterior fusion compared to posterior approach in 2 level II studies, while all 3 level III studies reported no difference between groups.

This recommendation is based on the near uniformity of results of the 4 randomized clinical trials. They did not show any differences in clinical results, including pain and neurologic recovery, between anterior and posterior approaches and only 1 level II study shows improved clinical outcomes in the posterior only treatment group compared to the combined group. The authors of this study recommended against the posterior approach despite having better clinical results because of poorer radiologic outcomes.⁵

Comparing anterior to posterior approaches, the radiologic outcomes were not different in the 2 level II studies, while the results were conflicting comparing posterior only to combined anterior-posterior approaches.

When comparing complications associated with anterior and posterior surgery, there was heterogeneity in the results in 2 level II studies, while all level III studies reported no differences. The combined anterior-posterior approach showed a higher complication risk in 2 of the 3 level II studies and no difference in one level II study.

Future Research

Future research is still needed to determine an optimum surgical approach for thoracolumbar fractures. Although there were 5 randomized controlled trials, these trials had significant deficiencies, including lack of power analysis, lack of description of randomization methods, and absent a priori identification of primary outcome variables. When developing the research plan, the use of the CONSORT method and reporting results is recommended. Many of the studies used outdated surgical techniques, so new studies using modern methods are needed. The results should be stratified based on neurologic injury and fracture types. The new methods to classify thoracolumbar fractures need to be incorporated into study design, and the results should be analyzed according to the severity of injury based on these schemes.  

Conclusion

Eleven studies compared outcomes between anterior and posterior approaches and anterior-posterior and posterior approaches. There was moderate evidence that no differences in clinical outcomes based on approach occur. In addition, conflicting evidence was present indicating that minimal differences in radiologic or complication risk exist between approaches. Thus, surgeons may choose any of 3 approaches when deciding optimal surgical treatment for thoracolumbar burst fractures.

Potential Conflicts of Interest

The task force members were required to report all possible conflicts of interest (COIs) prior to beginning work on the guideline, using the COI disclosure form of the AANS/CNS Joint Guidelines Review Committee, including potential COIs that are unrelated to the topic of the guideline. The CNS Guidelines Committee and Guideline Task Force Chairs reviewed the disclosures and either approved or disapproved the nomination. The CNS Guidelines Committee and Guideline Task Force Chairs are given latitude to approve nominations of Task Force members with possible conflicts and address this by restricting the writing and reviewing privileges of that person to topics unrelated to the possible COIs. The conflict of interest findings are provided in detail in the companion introduction and methods manuscript.

Disclaimer of Liability

This clinical systematic review and evidence-based guideline was developed by a multidisciplinary physician volunteer task force and serves as an educational tool designed to provide an accurate review of the subject matter covered. These guidelines are disseminated with the understanding that the recommendations by the authors and consultants who have collaborated in their development are not meant to replace the individualized care and treatment advice from a patient's physician(s). If medical advice or assistance is required, the services of a competent physician should be sought. The proposals contained in these guidelines may not be suitable for use in all circumstances. The choice to implement any particular recommendation contained in these guidelines must be made by a managing physician in light of the situation in each particular patient and on the basis of existing resources.

Disclosures

These evidence-based clinical practice guidelines were funded exclusively by the Congress of Neurological Surgeons and the Section on Disorders of the Spine and Peripheral Nerves in collaboration with the Section on Neurotrauma and Critical Care, which received no funding from outside commercial sources to support the development of this document.

Acknowledgments

The guidelines task force would like to acknowledge the CNS Guidelines Committee for their contributions throughout the development of the guideline and the AANS/CNS Joint Guidelines Review Committee for their review, comments, and suggestions throughout peer review, as well as the contributions of Trish Rehring, MPH, CHES, Senior Manager of Clinical Practice Guidelines for the CNS, and Mary Bodach, MLIS, Guidelines Specialist and Medical Librarian for assistance with the literature searches. Throughout the review process the reviewers and authors were blinded from one another. At this time, the guidelines task force would like to acknowledge the following individual peer reviewers for their contributions: Maya Babu, MD, MBA, Greg Hawryluk, MD, PhD, Steven Kalkanis, MD, Yi Lu, MD, PhD, Jeffrey J. Olson, MD, Martina Stippler, MD, Cheerag Upadhyaya, MD, MSc, and Robert Whitmore, MD.

REFERENCES

1. Ransohoff DF, Pignone M, Sox HC. How to decide whether a clinical practice guideline is trustworthy. JAMA 2013;309:139-40.

2. Hao D, Wang W, Duan K, et al. Two-year follow-up evaluation of surgical treatment for thoracolumbar fracture-dislocation. Spine 2014;39:E1284-E1290.

3. Wood K, Buttermann G, Mehbod A, Garvey T, Jhanjee R, Sechriest V. Operative compared with nonoperative treatment of a thoracolumbar burst fracture without neurological deficit. A prospective, randomized study. J Bone Joint Surg Am 2003;85A:773-781.

4. Lin B, Chen ZW, Guo ZM, Liu H, Yi ZK. Anterior approach versus posterior approach with subtotal corpectomy, decompression, and reconstruction of spine in the treatment of thoracolumbar burst fractures: a prospective randomized controlled study [published online ahead of print Jun 1]. J Spinal Disord Tech.

5. Korovessis P, Baikousis A, Zacharatos S, Petsinis G, Koureas G, Iliopoulos P. Combined anterior plus posterior stabilization versus posterior short-segment instrumentation and fusion for mid-lumbar (L2-L4) burst fractures. Spine 2006;31:859-868.

6. Esses SI, Botsford DJ, Kostuik JP. Evaluation of surgical treatment for burst fractures. Spine 1990;15:667-673.

7. Danisa OA, Shaffrey CI, Jane JA, et al. Surgical approaches for the correction of unstable thoracolumbar burst fractures: a retrospective analysis of treatment outcomes. J Neurosurg 1995;83:977-983.

8. Been HD, Bouma GJ. Comparison of two types of surgery for thoraco-lumbar burst fractures: combined anterior and posterior stabilisation vs. posterior instrumentation only. Acta Neurochir 1999;141:349-357.

9. Wu H, Wang CX, Gu CY, et al. Comparison of three different surgical approaches for treatment of thoracolumbar burst fracture. Chin J Traumatol 2013;16:31-35.

10. Hitchon PW, Torner J, Eichholz KM, Beeler SN. Comparison of anterolateral and posterior approaches in the management of thoracolumbar burst fractures. J Neurosurg Spine 2006;5:117-125.

11. Schmid R, Lindtner RA, Lill M, Blauth M, Krappinger D, Kammerlander C. Combined posteroanterior fusion versus transforaminal lumbar interbody fusion (TLIF) in thoracolumbar burst fractures. Injury 2012;43:475-479.

12. Sasso RC, Renkens K, Hanson D, Reilly T, McGuire Jr RA, Best NM. Unstable thoracolumbar burst fractures: anterior-only versus short-segment posterior fixation. J Spinal Disord Tech 2006;19:242-248.

Appendix I. Literature Searches

Search Strategies

PubMed

1.Lumbar vertebrae [MeSH] OR Thoracic vertebrae [MeSH]

2. Spinal Injuries [MeSH] OR Spinal Cord Injuries [MeSH]

3. #1 AND #2

4. Thoracolumbar [TIAB] OR thoraco-lumbar [TIAB] OR thoraco lumbar [TIAB] OR burst [Title]

5.Injur* [TIAB] OR trauma* [TIAB] OR fractur* [TIAB] OR dislocation* [TIAB]

6. #4 AND #5

7. Lumbar vertebrae/injuries [MeSH] OR Thoracic vertebrae/injuries [MeSH]

8. #3 OR #6 OR #7

9.Orthopedic Procedures [MeSH] OR Neurosurgical Procedures [MeSH] OR Decompression, surgical [MeSH] OR Orthopedic Fixation Devices [MeSH] OR surgery [SH] OR instrumentation [SH]

10.surgery[tiab] OR surgical[tiab] OR operati*[tiab] OR repair*[tiab] OR stabiliz*[tiab] OR fixation[tiab] OR reconstruct*[tiab] OR fusion[tiab] OR decompress*[tiab] OR spondylodes*[tiab] OR spondylosyndes*[tiab] OR arthrodes*[tiab] OR laminectomy[tiab] OR discectomy[tiab] OR diskectomy OR “percutaneous vertebral augmentation”[tiab] OR “bone screw”[tiab] OR “bone screws”[tiab] OR “bone plate”[tiab] OR “bone plates” [tiab] OR “pedicle screw”[tiab] OR “pedicle screws”[tiab]

11. #9 OR #10

12.Thoracoscopy [MeSH] OR Retroperitoneal space [MeSH] 

13.Anterior OR Circumferential OR lateral OR Posterior OR Posterolateral OR retroperitoneal OR thoracotomy OR thoracoscop* OR transthoracic OR thoracoabdominal [TIAB]

14.#12 OR #13

15.#11 AND #14

16. #8 AND #15

17. animal [MeSH] NOT human [MeSH]) OR cadaver [MeSH] OR cadaver* [Titl] OR comment [PT] OR letter [PT] OR editorial [PT] OR addresses [PT] OR news [PT] OR “newspaper article” [PT] OR case reports [PT]

18.#16 NOT #17

19.osteoporosis [MH] OR osteoporotic fractures [MH] OR osteoporo* [TITLE] OR spinal neoplasms [MH] OR tumor* [TITLE] OR tumour* [TITLE] OR malignan* [TITLE]

20.#18 NOT #19

21.12.#20 AND English [Lang]

Cochrane Library

1.Lumbar vertebrae: MeSH descriptor, explode all trees

2.Thoracic vertebrae: MeSH descriptor, explode all trees

3.#1 OR #2

4.Spinal Injuries: MeSH descriptor

5.Spinal Cord Injuries: MeSH descriptor

6.#4 OR #5

7.#3 AND #6

8.(Thoracolumbar OR thoraco-lumbar  OR thoraco lumbar OR burst) NEAR/4 (Injur* OR trauma*  OR fractur* OR dislocation*):ti,ab,kw

9.Lumbar vertebrae/injuries: MeSH descriptor, explode all trees

10.Thoracic vertebrae/injuries: MeSH descriptor, explode all trees

11.>#9 OR #10

12.>#7 OR #8 OR #11

13.>mh osteoporosis or mh osteoporotic fractures or mh spinal neoplasms

14.>osteoporo* or tumor* or malignan*:ti

15.>#13 OR #14

16.#12 NOT #15

Appendix II. Article Inclusions and Exclusions

Included and Excluded Articles Flowchart

Appendix III. Rating Evidence Quality

Levels of Evidence for Primary Research Question^a

RCT, Randomized controlled trial.

^aA complete assessment of quality of individual studies requires critical appraisal of all aspects of the study design.

^bA combination of results from ≥2 previous studies.

^cStudies provided consistent results.

^dStudy was started before the first patient enrolled.

^ePatients treated one way (e.g., instrumented arthrodesis) compared with a group of patients treated in another way (e.g., unsintrumented arthrodesis) at the same institution.

^fThe study was started after the first patient enrolled.

^gPatients identified for the study based on their outcome, called “cases” (e.g., pseudoarthrosis) are compared to those who did not have outcome, called “controls” (e.g., successful fusion).

^hPatients treated one way with no comparison group of patients treated in another way.

Appendix IV. Linking Levels of Evidence to Grades of Recommendation

^aNote that in the presence of multiple consistent studies, and a single outlying, inconsistent study, the Grade of Recommendation will be based on the level of the consistent studies.

Appendix V. Criteria Grading the Evidence

The task force used the criteria provided below to identify the strengths and weaknesses of the studies included in this guideline. Studies containing deficiencies were downgraded one level (no further downgrading allowed, unless so severe that study had to be excluded). Studies with no deficiencies based on study design and contained clinical information that dramatically altered current medical perceptions of topic were upgraded.

1. Baseline study design (i.e., therapeutic, diagnostic, prognostic) determined to assign initial level of evidence.
2. Therapeutic studies reviewed for following deficiencies:
   • Failure to provide a power calculation for an RCT;
   • High degree of variance or heterogeneity in patient populations with respect to presenting diagnosis/demographics or treatments applied;
   • <80% of patient follow-up;
   • Failure to utilize validated outcomes instrument;
   • No statistical analysis of results;
   • Cross over rate between treatment groups of >20%;
   • Inadequate reporting of baseline demographic data;
   • Small patient cohorts (relative to observed effects);
   • Failure to describe method of randomization;
   • Failure to provide flowchart following patients through course of study (RCT);
   • Failure to account for patients lost to follow-up;
   • Lack of independent post-treatment assessment (e.g., clinical, fusion status, etc.);
   • Utilization of inferior control group:
     • Historical controls;
     • Simultaneous application of intervention and control within same patient.
   • Failure to standardize surgical/intervention technique;
   • Inadequate radiographic technique to determine fusion status (e.g., static radiographs for instrumented fusion).
3.  Methodology of diagnostic studies reviewed for following deficiencies:
   • Failure to determine specificity and sensitivity;
   • Failure to determine inter- and intraobserver reliability;
   • Failure to provide correlation coefficient in the form of kappa values.
4.  Methodology of prognostic studies reviewed for following deficiencies:
   • High degree of variance or heterogeneity in patient populations with respect to presenting diagnosis/demographics or treatments applied;
   • Failure to appropriately define and assess independent and dependent variables (e.g., failure to use validated outcome measures when available).

Appendix VI. Evidence Table

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