Implant removal after short percutaneous pedicle fixation associated with SpineJack kyphoplasty: is correction sustained?

Purpose: This study objective was to evaluate sagittal correction loss after instrumentation removal in patients treated for thoracic or lumbar compression fractures treated with SpineJack kyphoplasty associated with short percutaneous pedicle screw fixation.

Methods: This retrospective multicenter study was carried out in three major French trauma centers. All patients with a single type A thoracic or lumbar fracture, treated by the studied technique between 2017 and 2020, have been included. Demographic data, fracture type, removal procedure achievement and term were collected. Radiological parameters were measured at five timepoints: pre-operative, intra-operative, immediate post-operative, early post-operative (< 3 months) and at follow-up (1 year). Vertebral wedge angle (angle between the two endplates of the fractured vertebra) and traumatic regional angulation (TRA-calculated by subtracting regional kyphosis from the physiological reference values).

Results: 150 patients were included. Mean age was 48.6 ± 17.8 years. Average follow-up was 14.4 ± 3 months. 82 patients had secondary instrumentation removal. Mean time to removal was 6.4 ± 2.4 months. TRA correction loss between immediate post-operative and last follow-up was greater in removal group: 5.1 ± 5.6° versus 2.7 ± 4.7° (p = 0.01). Material was removed earlier in younger patients (p = 0.002). TRA correction loss was similar in the early and late removal groups (p = 0.83). Multivariate analysis identified only Magerl/AO A3 fractures as risk factor for loss of TRA correction (p = 0.007).

Conclusion: Instrumentation removal was associated with good radiological outcomes with a non-significant loss of vertebral wedge angle and tolerable loss of traumatic regional angulation (+ 2.4° compared to the no-removal group), even if performed early.