Anatomical Study of the Lumbar Segmental Arteries in Relation to the Oblique Lateral Interbody Fusion Approach.

Objective: To use computed tomography angiography to evaluate the regional anatomy of the lumbar segmental arteries (LAs) associated with the surgical field in oblique lateral interbody fusion (OLIF).
Methods: Computed tomography angiography images from 50 patients were reviewed. In the sagittal plane, distances from the LA to the upper and inferior edges of the vertebral body were measured in the anterior quarter of the anterior and median lines of the intervertebral disc (IVD). LAs were classified as types I-IV based on the zone in which they passed through the vertebral body.
Results: The LA branch angles were acute (<90°) at L1-L3 and blunt (>90°) at L4-L5. The average distances from the LA to the upper and inferior edges of the vertebral body in the anterior quarter position revealed that La1.2 > Lb1.2 and Lb3.4.5 > La3.4.5. For the IVD of L1-L2, Lb1 < La2; IVD of L2-L3, Lb2 < La3; IVD of L3-L4, Lb3 > La4; IVD of L4-L5, Lb4 > La5. In zone I, the most frequent LA type was type IV at L1 (n = 41; 85.4%) and L2 (n = 42; 84.0%), type III at L3 (n = 20; 40.0%), and type II at L4 (n = 36; 80.0%) and L5 (n = 5; 83.3%). In zone II, the most frequent LA type was type III at L1 (n = 38; 79.2%), L2 (n = 39; 78.0%), L3 (n = 43; 86.0%), and L4 (n = 28; 62.2%), whereas type II was the most frequent LA type at L5 (n = 5; 83.3%). In zone III, type III was the most frequent LA type at L1-L4. In zone IV, type IV was the most frequent LA type at L3 (n = 44; 88.0%), L4 (n = 42; 93.3%), and L5 (n = 6; 100%).
Conclusions: The risk of LA injury during OLIF is the least when the cage is placed in zones II and III. Care is required during OLIF in zone IV of L3-L5. The fixation pin should be fixed on the upper edge of the lower vertebral body at L1-L2 and L2-L3, and on the lower edge of the upper vertebral body at L3-L4 and L4-L5.
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