Lightning Podiums: Smorgasboard - Room 802B

Presented by: S.-J. Park

Author(s):

S.-J. Park(1), C.-S. Lee(1), S.-S. Chung(1), K.-J. Lee(1)

(1) Samsung Medical Center, SungHyunKwan University School of Medicine, Orthopedic Surgery, Seoul, Korea, Republic of

Abstract

Study Design: Retrospective study

Summary of Background Data: Although case subsidence after oblique lumbar interbody fusion (OLIF) occurs frequently, especially in the first 3 months postoperatively, there are few data regarding its clinical and radiographic subsequences.

Purpose: To evaluate the impact on the clinical and radiographic outcome of the early cage subsidence after OLIF surgery.

Materials and Methods: The study cohorts included 53 patients who underwent OLIF surgery for 119 levels to treat degenerative lumbar diseases. OLIF cage was filled with allogenous bone graft mixed with DBM in all cases. The early cage subsidence was defined when cage suubsidence developed in the first 3 months after surgery. Cage subsidence was evaluated in plain radiographs and the degree of subsidence was measured from the endplate to the top of cage marker. The first detecting time to develop cage subsidence was recorded and the breached endplates were also evaluated. CT image was used to evaluate the fusion at 2-year follow-up. VAS for back, VAS for leg, ODI score and subjective satisfaction at 2-year follow-up were compared between subsidence group and non-subsidence group.

Results: The mean age of patients were 65.5. There were 10 males and 43 females. OLIF was performed in 47 levels at L4-5, 38 at L3-4, 24 at L2-3 and 10 at L1-2. The mean cage height was 13.1mm (range, 10-16). There were 59 levels with cage subsidence (49.7%). The mean first detecting time was 2.5 weeks. There were 28 levels (47.5%) with inferior endplate breaching, 16 levels (27.1%) with superior endplate breaching and 15 levels (25.450 with both endplate breaching. The initial amount of cage subsidence was 4.3mm and the last amount of subsidence increased significantly to be 6.3mm (p< 0.001). For all operated levels, CT scan revealed that solid fusion was obtained in 73.7%, partial union in 22.4% and nonunion in 3.9%. Howevere, there were no significant differences regarding the fusion rate between subsidence and non-subsidence group. There was no rod or screw breakage in all cases. There were also no sigificant differences in terms of VAS (back), VAS (leg), ODI score and subjective satisfaction between two groups.

Conclusion: The early cage subsidence ocurred in 49.7%. The amount of subsidence increased by 2 mm at 2-year follow-up. Cage subsidence did not impact negatively fusion rate or clinical outcomes.