*4.4. Decision-Making*

Removing the pedicle screw instrument after posterior fixation of thoracolumbar burst fractures can effectively restore flexibility and relieve pain, but can also result in the progression of kyphosis. Moreover, it is impossible to predict the recurrence of kyphotic deformity before implant removal, and extra revision surgery might be needed later if patients have severe back pain due to severe kyphotic deformity. Thus, careful consideration should be made before removing the implant.

In most symptomatic cases, the patient is the initiator of pedicle screw removal. Many patients with persistent symptoms tend to blame the metallic implants; they often insist on implant removal and believe this will alleviate their symptoms [67,68]. However, in clinical practice, even in patients who have reported implant-related pain, removing the implant does not guarantee pain relief and may be associated with further complications (such as infection, re-fracture, and nerve damage) and worsening pain [31,32,37,41]. Therefore, patients should be notified of indications for implant removal and understand the uncertainty of expected benefits, potential complications, and inherent risks. On the contrary, implant retention would reduce costs and alleviate exposure to further surgery, but patients should also be informed of the possibility of screw breakage.

Surgeons are the decision-makers of implant removal [18,67]. The decision of implant removal should be predetermined as early as the initial treatment of the thoracolumbar burst fractures and dynamically adjusted according to the patient's clinical status (Figure 2). Careful preoperative evaluation and consideration should be made before removing the implant. First of all, surgeons should review details of the primary thoracolumbar burst fractures, such as the mechanism of injury, the morphology, and classification of the burst fractures, and learn about the first surgical management. Second, surgeons need to assess the fusion of the burst fractures, which is critical but challenging, and even intra-operative exploration demonstrates that a solid fusion cannot promise desired outcomes [67]. Next, for symptomatic patients, surgeons should try to figure out to what extent the patient's pain and discomfort are associated with the pedicle screw instrument, and how much pain

relief can be expected from implant removal [69]. For example, postoperative pain may be attributed to instability, root pain, adjacent-level pathology, and factors related to the implant. Very often, the exact cause of post-instrumented pain remains difficult to determine. Finally, communication with patients is essential and crucial than ever before [41]. Patients should be informed thoroughly about the unpredictable outcomes of implant removal to avoid excessively high expectations [41]. Moreover, detailed preoperative evaluation before implant removal is also indispensable. For instance, a CT scan before implant removal would be beneficial for confirmation of posterolateral fusion and preoperative measurement of the bone mineral density of the fractured vertebral body and adjacent vertebral bodies to evaluate the risk of compression fracture after implant removal [31,32]. Based on these careful preoperative clinical evaluations and detailed communication, a decision to remove or retain the implants could be made. The timing of the removal of the implant remains an open question.
