Clinical and radiological evaluation of cage subsidence following oblique lumbar interbody fusion combined with anterolateral fixation

Abstract

Background Cage subsidence (CS) was previously reported as one of the most common complications following oblique lumbar interbody fusion (OLIF). We aimed to assess the impacts of CS on surgical results following OLIF combined with anterolateral fixation, and determine its radiological characteristics as well as related risk factors. Methods Two hundred and forty-two patients who underwent OLIF at L4-5 and with a minimum 12 months follow-up were reviewed. Patients were divided into three groups according to the extent of disk height (DH) decrease during follow-up: no CS (DH decrease ≤ 2 mm), mild CS (2 mm < DH decrease ≤ 4 mm) and severe CS (DH decrease > 4 mm). The clinical and radiological results were compared between groups to evaluate radiological features, clinical effects and risk factors of CS. Results CS was identified in 79 (32.6%) patients, including 48 (19.8%) with mild CS and 31 (11.8%) with severe CS. CS was mainly identified within 1 month postoperatively, it did not progress after 3 months postoperatively, and more noted in the caudal endplate (44, 55.7%). In terms of clinical results, patients in the mild CS group were significantly worse than those in the no CS group, and patients in the severe CS group were significantly worse than those in the mild CS group. There was no significant difference in fusion rate between no CS (92.6%, 151/163) and mild CS (83.3%, 40/48) groups. However, significant lower fusion rate was observed in severe CS group (64.5%, 20/31) compared to no CS group. CS related risk factors included osteoporosis (OR = 5.976), DH overdistraction (OR = 1.175), flat disk space (OR = 3.309) and endplate injury (OR = 6.135). Conclusion CS following OLIF was an early postoperative complication. Higher magnitudes of CS were associated with worse clinical improvements and lower intervertebral fusion. Osteoporosis and endplate injury were significant risk factors for CS. Additionally, flat disk space and DH over-distraction were also correlated with an increased probability of CS.

Reverse Lumbar Pedicle Screw in Oblique Lateral Interbody Fusion: A Novel Concept to Restrict Cage Subsidence

“…Controversies remained whether subsidence would directly contribute to radiculopathy recurrence and lead to enhanced risk of revision surgery. As illustrated previously, 6 severe cage subsidence (>4 mm) was tightly associated with worse patient-reported indicators including VAS and ODI, leading to lower fusion rate in long-term follow-up. Even the moderate subsidence (2-4 mm) would result in transient clinical worsening compared with the mild (<2 mm).…”

Cortical Endplate Bone Density Measured by Novel Phantomless Quantitative Computed Tomography May Predict Cage Subsidence more Conveniently and Accurately

“…Previous studies have shown that endplate vBMD (EP‐vBMD) measured by QCT with a 5 mm height ROI can be related to the cage subsidence of XLIF better compared to that of cancellous vBMD 15,16 . Similar studies on oblique lumbar interbody fusion (OLIF) also indicate that endplate injury is a vital risk factor of cage subsidence 17 . However, the osseous endplate thickness range is 0.35–1.03 mm, implying that the 5 mm height mainly comprises the trabecular bone 18–21 .…”

Bone Health Optimization (BHO) in Spine Surgery

“…There was an almost two-fold increased odds of proximal and distal junctional kyphosis in patients with osteopenia and osteoporosis (OR 1.95 and OR 1.88), respectively. 14 Zhao et al 15 reported on 242 patients undergoing oblique lumbar interbody fusion and found that osteoporosis was a significant risk factor for cage subsidence (OR = 6.0). The poor outcomes associated with osteoporosis have been reported both in the lumbar and the cervical spine.…”