Background:

Intraoperative endplate injury can result in late-onset cage subsidence in oblique lumbar interbody fusion (OLIF). This study aimed to identify risk factors for intraoperative endplate injury and investigate whether pear-shaped disc correlated with intraoperative endplate injury in OLIF.

Methods:

We retrospectively reviewed 102 levels in 82 patients (mean age 60.1±10.0 years) who underwent OLIF for degenerative lumbar diseases. Intraoperative endplate injury was evaluated using midline sagittal computed tomography views at 3 days postoperatively and defined as cage breaching into adjacent cortical endplate more than 2 mm. Patient demographics, surgical parameters, radiographic parameters, and cage-related parameters were recorded in all surgical levels. Evaluation of risk factors associated with intraoperative endplate injury was performed. Patient-reported outcome, fusion status, and late-onset cage subsidence were analyzed at a minimum of one year after the surgery.

Results:

Intraoperative endplate injury was observed in 26 levels (25.5%). Multivariate logistic regression analysis identified that bone mineral density (OR=0.978), preoperative segmental lordosis (OR=0.790) and pear-shaped disc were risk factors (OR=5.837) for intraoperative endplate injury. Intraoperative endplate injury occurred in 45.5% of levels with pear-shaped disc compared with 16.0% of levels with no pear-shaped disc (P<0.01). Late-onset cage subsidence was significantly more frequent in the injury group than in the no injury group. Patient-reported outcome and fusion status were unrelated to intraoperative endplate injury.

Conclusions:

Pear-shaped disc is the greatest risk factor for intraoperative endplate injury following OLIF.