LAUSR

BACKGROUND All interbody fusions are associated with a risk of subsidence. In the case of lateral lumbar interbody fusion (LLIF), an interbody device that spans the apophyseal rings reduces subsidence. Small interbody device size, aggressive end plate preparation, and poor bone quality are contributors to subsidence. The goal of this study was to analyze the perioperative morbidity, particularly the timing of subsidence (intraoperative vs postoperative), associated with transpsoas LLIF. METHODS A retrospective review of consecutive LLIF cases was performed. Perioperative complications were reviewed. Intraoperative fluoroscopy as well as postoperative radiography, computed tomography, and magnetic resonance imaging were reviewed. RESULTS Seventy-seven consecutive patients (39 male; mean [range] age, 66.2 [46-86] years) were identified. Subsidence occurred in 3 patients (4%) and was found to occur exclusively in the intraoperative setting. Anterior thigh paresthesias lasting longer than 24 hours occurred in 2 patients (3%). No femoral nerve injuries manifesting as weakness were observed. No visceral, vascular, or ureter injuries were identified. CONCLUSION As LLIF becomes more common, it is important to better understand common complications, such as subsidence, and the specific rates at which they occur. A unique finding of exclusive intraoperative subsidence was observed. The use of cage size to obtain segmental lordotic correction and indirect decompression must be weighed against the potential risk of subsidence.