A Modified Anterior Column Realignment with Partial Anterior Longitudinal Ligament Release in Oblique Lateral Interbody Fusion

Abstract

STUDY DESIGN: Retrospective radiological analysis. OBJECTIVE: To demonstrate the radiological outcome after a modified anterior column realignment (mACR) with partial anterior longitudinal ligament (ALL) release in oblique lateral interbody fusion (OLIF). SUMMARY OF BACKGROUND DATA: Anterior column realignment (ACR) remains a powerful sagittal correction technique in minimally invasive adult spinal deformity surgery and is often combined with posterior column osteotomy (PCO) to achieve more lordosis. OLIF is ideal for ACR because the anterior-to-psoas corridor typically involves the anterolateral half of the disk. METHODS: This study included 112 operated disk levels of 101 consecutive patients who underwent OLIF between L2-L3 and L4-L5 using a 12 degrees lateral cage. The mACR was performed at 73 (65.2%) levels with 30% to 50% sectioning of the ALL. Each operated level was grouped according to the mACR and additional PCO as: (1) no mACR, OLIF only (n=39); (2) mACR with no PCO (n=18); (3) mACR with grade 1 PCO (n=27); (4) mACR with grade 2 PCO (n=22); or (5) mACR with grade 3 PCO (n=6). RESULTS: At the last follow-up, the mean disk lordotic angles were 10.9+/-2.9 degrees , 12.6+/-3.0 degrees , 13.3+/-3.9 degrees , 16.7+/-3.2 degrees , and 16.8+/-2.4 degrees in the no mACR, mACR with no PCO, mACR with grade 1 PCO, mACR with grade 2 PCO, and mACR with grade 3 PCO groups, respectively ( P <0.001). The mean increases in disk lordotic angle were 5.8+/-4.1 degrees , 12.1+/-6.1 degrees , 13.5+/-8.7 degrees , 15.8+/-6.7 degrees , and 17.9+/-6.2 degrees in each group, respectively ( P <0.001). CONCLUSIONS: ACR can be performed with partial ALL release under direct vision in OLIF without deep dissection into the ventral disk space. The mACR in OLIF is a simple, safe, and effective technique for anterior column lengthening. LEVEL OF EVIDENCE: 4.