Single-incision four-level oblique lateral interbody fusion and cement-augmented fixation in a severely osteoporotic lumbar spine: a case report

Background: Multilevel degenerative lumbar instability in patients with severe osteoporosis presents considerable surgical challenges due to compromised bone quality and increased risk of instrumentation failure. Oblique lateral interbody fusion (OLIF) offers a minimally invasive corridor for interbody fusion and deformity correction, typically enabling access to up to three adjacent disc levels through a single incision using the “sliding window” technique. Extension of OLIF to four levels via a single approach is rarely reported, particularly in the osteoporotic population, due to anatomical limitations and concerns about fixation stability. Case Description: We report the case of a 67-year-old woman with advanced osteoporosis who presented with severe low back pain, neurogenic claudication, and progressive lower limb weakness. Radiographs and magnetic resonance imaging (MRI) revealed degenerative lumbar scoliosis, multilevel vacuum disc phenomena, Meyerding grade I–II spondylolistheses, and severe foraminal stenosis from L2 to S1. After preoperative optimization with teriparatide therapy, a two-stage surgical strategy was implemented. The first stage involved a single-access, four-level OLIF (L2–S1) using the sliding window technique to restore disc height and alignment. The second stage consisted of percutaneous pedicle screw fixation from L2 to S1 with polymethylmethacrylate (PMMA) cement augmentation to enhance screw stability in the osteoporotic vertebrae. Both stages were completed without complications. The patient experienced significant postoperative improvement, including pain reduction and restoration of independent ambulation. Conclusions: This case demonstrates that four-level OLIF can be safely performed through a single incision even in patients with severe osteoporosis when using a staged surgical approach and cement-augmented fixation. This combined strategy offers a viable, minimally invasive solution for complex multilevel lumbar instability in high-risk patients, providing substantial symptom relief and functional recovery.