Short-term clinical and radiographic evaluation of patients treated with expandable and static interbody spacers following lumbar lateral interbody fusion

Objective The goal of this study was to evaluate, using computed tomography (CT) and magnetic resonance imaging (MRI), patients who underwent oblique lateral interbody fusion (OLIF) using either expandable or static interbody spacers. Methods Thirty-five patients with degenerative disc disease were surgically treated with one-level OLIF and were followed up for more than six months. The Static group consisted of 22 patients, and 13 patients were in the Expandable group. Intraoperative findings included operative time (min), blood loss (ml), and cage size.Low back pain, leg pain, and leg numbness were measured using the Japanese Orthopedic Association score, visual analogue score, and the Roland–Morris Disability Questionnaire. Radiological evaluation using CT and MRI allowed measurement of cage subsidence, cross-sectional area (CSA) of the dural sac, disc height, segmental lordosis, foraminal height, and foraminal CSA preoperatively and six months postoperatively. Results The Expandable group had significantly larger cage height and lordosis than the Static group (p < 0.05). The Expandable group also had greater dural sac area expansion and enlargement of the intervertebral foramen, as well as better correction of vertebral body slip (p < 0.05). Cage subsidence was significantly lower in the Expandable group (p < 0.05). JOA score and VAS for leg numbness were significantly better in the Expandable group (p < 0.05). Conclusions Compared with static spacers, expandable spacers significantly enlarged the dural sac area, corrected vertebral body slippage, expanded the intervertebral foramen, and achieved good indirect decompression while reducing cage subsidence, resulting in improvement in clinical symptoms.