Fig. 2.

Case example of a perioperative AE: a 75 yo female was evaluated for severe back pain (VAS back 8, ODI 56). Full spine X-Rays shows a sagittal imbalance (PI-LL 41°, SVA 73 ​mm) (Panel A). The patient was therefore operated for deformity correction with a two stage surgery: first, extreme lateral interbody fusion (XLIF) was performed at L3-L4 and L4-L5; second, a posterior fusion from T10 to pelvis was done, with prophylactic vertebroplasty (VP) at T9 and T10 (Panel B). Seven days after surgery the patient complained of low back pain of sudden onset, so an MRI was performed (Panel C), without any pathological finding. Three days later, the patient developed paraplegya: a whole spine CT scan was performed (Panel D), that showed a fracture of T10 (Chance Fracture, AO B1) (Yellow Arrow); the fracture happened because of the complete ossification of the ALL starting from the level above the end of the instrumentation (White Arrow), thus leaving T10 in between two rigid segments; furthermore, the VP needles could have weakened the pedicles, increasing the risk of a Chance Fracture. The patient underwent emergency surgery with posterior decompression and extension of the instrumentation to T2 (Panel E, F). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)