Lateral lumbar interbody fusion with lateral plating: techniques, feasibility and efficacy.

Abstract

Purpose: Standalone lateral lumbar interbody fusion (LLIF) enables single-position surgery and avoids the complications of posterior instrumentation though the lack of fixation may risk non-union and cage subsidence. Performing lateral plating following cage insertion may avert these untoward outcomes though the feasibility and efficacy of this approach, particularly with a four-hole plate, has been scarcely examined. The aim of this study is to review the techniques and appraise the performance of LLIF with lateral plating through analyzing a comprehensive set of clinical and radiographic case series data.

Methods: A retrospective study was conducted on a series of 55 lateral plating LLIF patients with lumbar degenerative disease. Patients with significant deformity (Cobb angle > 20° and grade 2 spondylolisthesis) were excluded. Clinical outcomes were rated by patient reported outcome measures (PROMs). Non-union and cage subsidence were evaluated by computed tomography (CT) scans performed at 12 months post-surgery or beyond.

Results: A four-hole plate was successfully implanted in 65 out of 77 operative levels. The remainder had a two-hole plate inserted. Postoperative psoas weakness occurred in eight patients (15%) and thigh or groin numbness in 10 (18%). All had complete or near complete resolution at the last follow-up. Of 68 operative levels with postoperative CT available, non-union was noted in eight (12%) and cage subsidence in 14 (21%), all low grade. Significant improvement in mean PROMs scores were demonstrated in patients with non-union or cage subsidence and none required reoperation. Multivariable logistic regression analyses revealed smoking (p = 0.002) and a lack of bicortical screw purchase (p = 0.038) were significant predictors for cage subsidence.

Conclusion: A four-screw plating construct is a safe and feasible fixation technique for LLIF. The treatment paradigm is associated with significant improvement in PROMs and a favorable fusion rate. Low grade cage subsidence is a potential caveat though this may not translate into poorer clinical outcomes. Fixation with bicortical screws may help reduce the odds of cage subsidence.