Postoperative loss of correction after combined posterior and anterior spinal fusion surgeries in a lumbar burst fracture patient with Class II obesity.

Background: When treating thoracolumbar fractures with severe cranial endplate injury but no or slight caudal endplate injury, it is debatable whether anterior fusion should be performed only for the injured cranial level, or for both cranial and caudal levels. We report an unexpected postoperative correction loss after combined multilevel posterior and single-level anterior fusion surgery in a patient with obesity. Case Description: A 28-year-old male with Class II obesity was brought to the emergency room with an L1 burst fracture with spinal canal involvement. Cranial endplate injury was severe, whereas caudal endplate injury was mild. The first surgery with 1-above 1-below posterior fixation failed to achieve sufficient stability; thus, additional surgeries (3-above 3-below posterior fixation and single-level T12-L1 anterior fusion) were performed. Postoperatively, the local kyphosis angle (LKA) between T12 and L2 was 22° in the lateral lying position and 29° in the standing position. Twenty-one-month post surgery, bony fusion between T12 and L1 was observed, and the LKA was 28° in both the lateral lying and standing positions. After posterior implants were removed 24 months after the surgery, significant correction loss both at the T12-L1 segment (6°) and L1-L2 segment (6°) occurred, and LKA was 40° at the final follow-up. Conclusion: In this patient, an intense axial load due to excessive body weight was at least one of the causes of postoperative correction loss. Postural differences in LKA may be useful to evaluate the stability of thoracolumbar fractures after fusion surgery and to predict postoperative correction loss.