Minimally invasive deformity correction using microendoscopic extraforaminal lumbar interbody fusion (ME-ELIF) for adult spinal deformity: a case report.

BACKGROUND: Adult spinal deformity (ASD) is associated with progressive sagittal and coronal imbalance, leading to functional decline and decreased quality of life. While minimally invasive approaches, such as lateral lumbar interbody fusion, have gained popularity, they pose risks to the abdominal vessels and the lumbar plexus. Microendoscopic extraforaminal lumbar interbody fusion (ME-ELIF) provides a posterolateral corridor to the disc space, avoiding these anterior structures. However, reports of ME-ELIF for ASD correction are limited. CASE PRESENTATION: A 73-year-old woman presented with low back pain and impaired standing tolerance. Radiographs showed a sagittal vertical axis (SVA) of 127 mm and a PI-LL mismatch of 32°, with preserved flexibility on fulcrum-bending films. ME-TLIF was performed at L4/5 due to facet fusion, and ME-ELIF was performed at L2/3, L3/4, and L5/S. Percutaneous pedicle screw fixation from T7 to the sacropelvis was utilized for global correction. RESULTS: Postoperative standing radiographs demonstrated improvements in SVA (127 mm → 45 mm) and PI-LL mismatch (32° → 11°). The coronal vertical axis improved from 65 mm to 7 mm. The Oswestry Disability Index improved from 51% preoperatively to 31% at 6 months. No neurological complications were observed. CONCLUSION: ME-ELIF can provide effective sagittal and coronal realignment in flexible ASD while minimizing approach-related morbidity. This technique may serve as a valuable minimally invasive alternative in selected cases.