*4.5. Call for Future Studies*

The currently available evidence for removing or retaining the pedicle screw instrument in thoracolumbar burst fractures is heterogeneous, limited, and insufficient. Thus, more prospective cohort studies and clinical trials with long-term follow-ups are strongly warranted to provide additional details about the advantages and disadvantages of each option, which would help mitigate the trade-off between the benefits and harms of different treatment options. Second, there is a desperate need to explore the biological mechanisms and clinical determinants of symptomatic and asymptomatic implants, as well as the risk factors and predictive parameters for the recurrence of kyphotic deformity, which will contribute to developing clinical decision rules that may determine which patient subgroup will benefit most from implant removal and which patient subgroup will face more risks [69,70]. Next, future studies should compare the same types of fractures (e.g., incomplete vs. complete burst fractures) when evaluating the outcomes of removing or retaining pedicle screw instruments after thoracolumbar burst fractures, which would help to observe actual clinical outcomes and avoid confusing the effects of fracture types. Additionally, pedicle screw removal is a second surgery performed under general anesthesia, which has substantial economic implications; therefore, a cost-effectiveness analysis should also be performed for policymakers, decision-makers, and other stakeholders [52,69,71].

#### *4.6. Limitations*

This study has several weaknesses. First, there was substantial clinical heterogeneity among the included studies, including the patient populations (e.g., symptomatic or asymptomatic), the morphology and classification of thoracolumbar burst fractures (e.g., incomplete or complete burst fractures), the severity of injury (e.g., the degree of injury to the discs, the integrity of the posterior ligamentous complex), the treatment strategies of thoracolumbar burst fractures, criteria for implant removal, follow-up duration, etc. These discrepancies reflect the lack of consensus on thoracolumbar burst fractures and compromise the quality of evidence. Second, this study was predetermined to include all kinds of studies, including case reports and case series, which may induce remarkable publication bias, since studies with positive results (e.g., unexpected complications) are more likely to be published in peer-reviewed journals [71]. Third, 25 of 35 included studies were from Asia, mainly from China, Japan, and South Korea, which may also induce bias.

**Figure 2.** A proposed flow diagram for the management of thoracolumbar burst fractures. Abbreviations: CT, Computed Tomography; MRI, Magnetic Resonance Imaging; ASIA, American Spinal Injury Association; TLICS, Thoracolumbar Injury Classification and Severity; PMMA, Polymethyl Methacrylate; BMI, Body Mass Index; BMD, Bone Mineral Density.
