Thoracolumbar Burst Fractures

A Systematic Review and Meta-Analysis Comparing Posterior-Only Instrumentation Versus Combined Anterior-Posterior Instrumentation

Hannah Hughes, BScArch, MB, BCh, BAO, MRCSI; Andrea Mc Carthy, BSc; Gerard Anthony Sheridan, MB, BCh, BAO, FRCSI; Jake Mc Donnell, MB, BCh, BAO; Frank Doyle, PhD; Joseph Butler, MB, BCh, BAO, FRCSI

Disclosures

Spine. 2021;46(15):E840-E849. 

In This Article

Discussion

This review endeavored to investigate the profile of outcomes associated with two commonly used methods of surgical intervention for TLBFs. Enhancing the understanding of how these surgical interventions influence post-operative outcomes allows surgeons to optimize perioperative planning and resources. Measurement and comparison of PROMS empowers all members of a team to deliver the best possible multi-disciplinary, patient-centerd care. Better understanding of outcomes in relation to kyphosis correction, as well as key negative outcomes such as blood loss, complications, and loss of kyphosis correction facilitates surgeons in the process of providing their patients with comprehensive, informed consent.

A significant degree of uncertainty still exists in relation to the optimal strategy for the surgical management of TLBFs. Combined instrumentation is associated with higher healthcare costs and patient-related costs in terms of associated morbidity.[8] However, the resultant morbidity from instrumentation failure and loss of kyphosis correction associated with posterior-only instrumentation also carries a significant cost to healthcare systems and patients.[8]

There are two prior meta-analyses examining posterior-only versus combined anterior-posterior instrumentation for TLBFs.[6,14] Oprel et al[6] included five observational studies, with a total of 755 patients. They found that postoperative kyphosis correction was significantly higher in the combined instrumentation group, with no significant difference found in the loss of kyphosis correction between posterior-only and combined instrumentation.[6] These findings are discordant with the results of the present review. In agreement with the current review, Oprel et al[6] found no significant difference in the rate of complications between the two types of surgical instrumentation. The most recent review by Tan et al,[14] published in 2020, concluded its literature search in December 2018. Their qualitative review included five observational studies.[14] Two of these five studies reported on LOS, operative time, and blood loss, with no consensus found on the superiority of either surgical approach.[14] The study's meta-analysis included two observational studies, with a total of 170 patients.[14] No significant difference was found in the change in Cobb angle (degree of kyphosis) at final follow-up, which is in disagreement with the findings of this meta-analysis.[14]

The evidence available for comparing posterior-only and combined instrumentation for TLBFs for the purpose of the current meta-analysis was limited to four RCTs with a total of 145 patients. This review demonstrates that in the surgical management of TLBFs, a combined instrumentation strategy was superior to posterior-only instrumentation in relation to maintaining kyphosis correction long-term. However, it was disadvantageous in terms of blood loss, operative time, and postoperative LOS, with no significant difference in PROMS between the two approaches. This would lead one to consider that the negative clinical outcomes associated with combined instrumentation potentially outweigh the long-term maintenance of kyphosis, especially when the difference is not clinically perceived from the patient's perspective. However, the validity of the meta-analysis for this outcome is limited due to the variable duration in follow-up between two of the analyzed studies.[2,10]

PROMS often represent the outcomes of most importance to patients and provide key insight in to the overall effect of a treatment.[23] Tools that enable reliable and sensitive measures of the effectiveness of surgical interventions are becoming an integral component of trauma care due to the increasing rate of survival from serious trauma.[24] In relation to VAS pain scores and ODI quality of life ratings, this review demonstrated no superiority between posterior and combined instrumentation for TLBFs.

In relation to operative time, it is important to note that it is often related to the degree of the primary operator's experience. In addition, as the more traditional surgical approach, posterior-only instrumentation may represent the preferred strategy for the majority of spine surgeons.[1] Furthermore, the addition of a second means of instrumentation, in this case, anterior instrumentation, will understandably increase the overall operative time of the surgical intervention.

LOS is important for a number of reasons. Longer hospital stays are associated with higher healthcare costs for treating institutions. For patients, longer in-hospital admissions place them at a higher risk of developing hospital-acquired infections.[25] There was significant heterogeneity observed in relation to this outcome, however, it would be reasonable to assume that different institutions and surgeons will have varied protocols regarding postoperative management and discharge, which may be attributable to some of the heterogeneity encountered.

This review found no significant difference in the degree of postoperative kyphosis correction. The purpose of instrumentation and fixation for TLBFs is to provide stability, particularly of the middle column as defined by the Denis three-column theory, in order to prevent neurological deterioration and progressive kyphosis, which can lead to significant pain and functional morbidity.[8,26] The use of titanium mesh cages filled with autologous bone graft to reconstruct defects created by decompressive corpectomy allows for restoration of kyphosis and vertebral body height during the anterior portion of combined instrumentation, which may confer enhanced stability in relation to preventing progressive postoperative kyphosis.[1]

It is important to note that with the advent and development of new technology, the way in which TLBFs are treated is changing.[27,28] In recent decades, the development of minimally invasive surgical (MIS) techniques has led to a reduction in intraoperative blood loss, tissue trauma, postoperative pain, and LOS.[29] Methods of MIS range from fluoroscopic-assisted percutaneous trans-pedicular screw-rod fixation to computerized tomography (CT) based 3D navigated systems and robotic-assisted surgery. Despite the associated benefits, universal adoption and implementation of newer MIS robotic technologies is hindered by many current value-based health-care models and by health systems that lack sufficient funding for up-front costs and training provision.[28] As a result, navigated, non-robotic pedicle screw instrumentation remains the most commonly used method for TLBF fixation.[27,30]

This review has several strengths. It is the most up to date regarding the comparison of posterior-only versus combined surgical instrumentation for TLBFs. Only RCTs were considered for inclusion to ensure the highest level of literature was used for the meta-analysis. There were some limitations in relation to the completeness and availability of evidence across the four included trials. Specific methods of each surgical intervention were not identical across all trials. In addition, the data for all outcomes of interest were not complete across all studies. Furthermore, the review process was not without potential bias. Firstly, attempts to retrieve missing information from trial investigators were unsuccessful. Secondly, blinding of participants and outcomes is an inherent limitation to performing a RCT in relation to surgical interventions.[31] The use of PROMS, as discussed, is also a potential source of reporting bias within trials.[32]

This review highlights the significant limitations of the current, available literature, and its associated low to moderate grade of quality. Therefore, the conclusions drawn are tentative in nature. In order to reliably and accurately inform practice in this area, there is a need for a large, high quality, multicenter RCT assessing the effects of posterior-only versus combined instrumentation for TLBFs. There should be agreement on the outcomes of primary importance and standardized reporting of these outcomes in order to aid consistency across studies. Particular focus should be placed on collecting PROMS relating to pain, function, and outcomes relating to severe complications leading to long-term morbidity. The importance of patient-centered decision-making is paramount and ultimately, the optimal surgical approach should be carefully considered on a case-by-case basis.

processing....