Comparing Lumbar Fusion With and Without Stress Endplate Augmentation in Patients With Low Bone Mass

Degenerative lumbar disease can cause back pain, leg pain, and difficulty with daily activities. Some patients require lumbar fusion surgery. In patients with low bone mass, the bones may provide less support for the interbody cage, an implant placed between two vertebrae. The cage may sink into the surrounding bone after surgery, a complication known as cage subsidence. Stress endplate augmentation strengthens the bone near the surfaces supporting the cage, but its benefits and risks require further evaluation. This single-center prospective observational cohort study will compare outcomes in patients undergoing oblique lumbar interbody fusion (OLIF) with or without stress endplate augmentation. Consecutive eligible patients aged 50 years or older with low bone mass and degenerative lumbar disease will be enrolled before surgery and followed for 18 months afterward. Whether stress endplate augmentation is performed will be determined by the treating surgeon and patient through routine clinical decision-making. The study will not assign treatment. Patients will be grouped according to whether they receive stress endplate augmentation. The main outcome will be cage subsidence at 18 months after surgery. Other outcomes will include spinal fusion, changes in spinal measurements on imaging, back and leg pain, functional disability, surgical and hospitalization measures, and complications. Clinical information, bone density measurements, imaging findings, and patient-reported outcomes will be collected before surgery and during follow-up. Comparisons will account for differences in patient characteristics and surgical factors. The study aims to clarify the benefits and risks associated with stress endplate augmentation in patients with low bone mass undergoing OLIF.

Inclusion Criteria: 1. Age 50 years or older. 2. Degenerative lumbar disease diagnosed clinically and by imaging, including lumbar spinal stenosis, degenerative spondylolisthesis, or degenerative disc disease. 3. Persistent symptoms despite appropriate nonsurgical treatment, with a clinical indication for surgery. 4. Scheduled to undergo oblique lumbar interbody fusion (OLIF). 5. Low bone mass identified by preoperative dual-energy X-ray absorptiometry (DXA), defined as a T-score below -1.0 at a valid measurement site. 6. Ability and willingness to complete the required imaging examinations, patient-reported outcome assessments, and follow-up through 18 months after surgery. 7. Ability to understand the study and provision of written informed consent before enrollment. Exclusion Criteria: 1. Previous lumbar spine surgery. 2. Nondegenerative lumbar conditions, including spinal infection, tumor, or acute trauma. 3. Severe vertebral compression fracture. 4. Grade II or higher lumbar spondylolisthesis, or spinal deformity requiring complex osteotomy or other major corrective surgery. 5. Inability to complete the required imaging examinations or scheduled follow-up. 6. Other conditions that, in the investigator's judgment, make participation unsuitable.