Risk factors for kyphosis recurrence after implant removal in percutaneous osteosynthesis for post-traumatic thoracolumbar fracture.

Purpose: Short-segment minimally invasive percutaneous spinal osteosynthesis has now become one of the treatments of choice to treat thoracolumbar fractures. The question of implant removal once the fracture has healed is still a matter of debate since this procedure can be associated with loss of sagittal correction. Therefore, we analyzed risk factors for kyphosis recurrence after spinal implants removal in patients treated with short-segment minimally invasive percutaneous spinal instrumentation for a thoracolumbar fracture.

Methods: A total of 32 patients who underwent implant removal in percutaneous osteosynthesis for post-traumatic thoracolumbar fracture were enrolled in our study. Patient's medical record, operative report and imaging examinations carried out at the trauma and during the follow-up were analyzed.

Results: Every patient experienced fracture union. Vertebral kyphotic angle (VKA) and Cobb angle (CA) improved significantly after stabilization surgery. VKA, CA, upper disk kyphotic angle (UDKA) and lower disk kyphotic angle (LDKA) significantly gradually decreased during follow-up. Traumatic disk injury (p: 0.001), younger age (p: 0.01), canal compromise (p: 0.04) and importance of surgical correction (p < 0.001) were significantly associated with kyphosis recurrence after implant removal. Anterior body augmentation did not affect loss of correction (CA and VKA) during the follow-up period (p: 0.57).

Conclusion: Despite correction of the fracture after stabilization, we observed a progressive loss of correction over time appearing even before implant removal. Particular attention should be paid to post-traumatic disk damage or canal invasion, to young patients and to surgical overcorrection of the traumatic kyphosis.