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

Results

In total, 692 studies were identified through the search strategy described. On full text screening, four publications that met the inclusion criteria were included in the meta-analysis (Figure 1).

Figure 1.

PRISMA flow diagram demonstrating results of literature search. PRISMA indicates Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

All studies were RCTs and were published between 2014 and 2019. All studies reported on the two surgical approaches of interest for TLBFs.[2,8–10] One study, Wang et al,[9] contained a third trial arm investigating anterior-only instrumentation, however, this trial arm was not included in our analysis. The characteristics of the four included studies are detailed in Table 1. All studies were published in English, performed in a single-center and conducted in the hospital setting.[2,8–10]

Demographics

In total, 145 randomized participants were included in the analysis, of which 73 (51%) underwent posterior-only instrumentation and 72 (49%) underwent combined instrumentation. Patient demographics and trial characteristics are detailed in Table 2. Male sex accounted for 66% (n = 96) and 34% (n = 49) of all patients treated by posterior-only instrumentation and combined instrumentation, respectively. All four studies reported the distribution of fracture levels (Table 2). For patients treated with posterior-only instrumentation, the most common fracture level observed was L1 (58%, n = 42), followed by L2 (23%, n = 17) and subsequently T12 (19%, n = 14). Similarly, for patients treated with combined instrumentation, the most common level fractured was L1 (57%, n = 41), followed by L2 (24%, n = 17) and T12 (19%, n = 14). The surgical approaches used in each study are detailed in Table 2.

Outcomes

Significant heterogeneity was found in the methods of reporting surgical outcomes and complications in the analyzed trials. In relation to clinical outcomes, three studies estimated intraoperative blood loss,[2,9,10] two recorded LOS in days,[2,9] three studies reported estimated intraoperative blood loss in millilitres,[2,9,10] and two reported operative time for each surgical approach.[9,10] All studies reported postoperative complications and specified the number and type of complications that occurred.[2,8–10] With regard to PROMS, three studies reported VAS score at final follow-up [2,9,10] and three reported ODI at final follow-up.[2,8,10] In relation to radiological outcomes, all studies used the standardized and established Cobb's method of calculating the degree of segmental kyphosis across the fracture level.[20,21] Two studies reported on the degree of kyphosis at final follow-up.[2,9] Two studies reported the loss of kyphosis correction observed at final follow-up.[2,10] The clinical, functional, and radiological outcomes for each approach are detailed in Table 3. When a significant degree of heterogeneity was observed for an outcome, subgroup analysis was not performed due to the small number of studies included in the meta-analysis.[22]

The risk of bias in the four included studies is displayed in Figure 2. In relation to blinding of participants and personnel, all four studies were rated as having a high risk of bias due to the nature of interventions and the informed-consent process.[2,8–10]

Figure 2.

Risk of bias summary for included studies. +: low risk of bias; ?: unclear risk of bias; –: high risk of bias.

Results of Meta-analysis

Radiological Outcomes. Two studies reported on the degree of postoperative kyphosis correction.[2,10] Random-effects meta-analysis (RMA) demonstrated no superiority between posterior-only and combined instrumentation [WMD 1.11, 95% CI –1.42–3.64; P = 0.39] (Figure 3). Two studies reported on the degree of loss of kyphosis correction at final follow-up.[2,10] RMA favored combined instrumentation [WMD –1.53, 95% CI –2.45 to –0.61; P = 0.001] (Figure 4). The duration of the follow-up period in the two studies reporting this outcome varied significantly, which may reduce the validity of the analysis for the loss of kyphosis correction at final follow-up (Table 2).

Figure 3.

Forest plot for postoperative kyphosis correction. CI indicates confidence interval; IV, inverse-variance method; Random, random-effects meta-analysis; SD, standard deviation.

Figure 4.

Forest plot for loss of kyphosis correction. CI indicates confidence interval; IV, inverse-variance method; Random, random-effects meta-analysis; SD, standard deviation.

Functional Outcomes. Three studies reported VAS scores.[2,9,10] RMA demonstrated no superiority between posterior-only and combined instrumentation [WMD –0.21, 95% CI –1.15–0.74; P = 0.67]. Three studies reported ODI.[2,9,10] RMA demonstrated no superiority between posterior-only and combined instrumentation [WMD –0.03, 95% CI –2.8 to –2.74; P = 0.98].

Clinical Outcomes. Three studies reported intraoperative blood loss.[2,8,10] RMA favored posterior-only instrumentation [WMD 356.78, 95% CI 160.88–552.69; P < 0.001] (Figure 5). Only one study reported the method via which intraoperative blood loss was estimated.[2] Two studies reported operative time.[9,10] RMA favored posterior-only instrumentation [WMD 133.12, 95% CI 116.83–149.41; P < 0.001] (Figure 6). Two studies reported LOS.[2,9] RMA favored posterior-only instrumentation [WMD 5.73, 95% CI 1.23–10.23; P = 0.01] (Figure 7).

Figure 5.

Forest plot for intraoperative blood loss. CI indicates confidence interval; IV, inverse-variance method; Random, random-effects meta-analysis; SD, standard deviation.

Figure 6.

Forest plot for operative time. CI indicates confidence interval; IV, inverse-variance method; Random, random-effects meta-analysis; SD, standard deviation.

Figure 7.

Forest plot for LOS. CI indicates confidence interval; IV, inverse-variance method; LOS, length of stay; Random, random-effects meta-analysis; SD, standard deviation.

All studies reported on number and type of postoperative complications.[2,8–10] RMA demonstrated no superiority between posterior-only and combined instrumentation [RR 1.50, 95% CI 0.47–4.79; P = 0.49] (Figure 8). Combined instrumentation was the intervention with the highest rate of complications at 19% (n = 14), while the complication rate of the posterior group was 11% (n = 8).

Figure 8.

Forest plot for number of postoperative complications. CI indicates confidence interval; M-H, Mantel-Haenszel method; Random, random-effects meta-analysis; SD, standard deviation.

The evidence for each outcome of interest was graded low to moderate, as per the GRADE approach, in relation to internal and external validity of outcomes, including study design, risk of bias, inconsistency, indirectness, imprecision, and the detection of publication bias.[18]

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