MDT-0123 Japan Study

Inclusion Criteria: * Requirement for bone fusion via consecutive 2-level spinal fusion due to disc degeneration or spinal deformity in the lumbosacral spine (L2-S1) * Symptomatic degenerative lesions from L2 to S1 confirmed by imaging (MRI or myelography within 12 months prior to enrollment) with neurological symptoms due to nerve root compression, including radiating pain, sensory disturbance, numbness, weakness, or neurogenic claudication * Degenerative disc disease with discogenic back pain, with or without leg pain, supported by clinical history and radiographic findings (e.g., CT, MRI, X-ray), with at least one of the following: instability (angular motion ≥5° and/or translation ≥4 mm), osteophyte formation, decreased intervertebral disc height, ligamentous thickening, disc degeneration or herniation, or facet joint degeneration * Preoperative Oswestry Disability Index (ODI) score ≥35% * Skeletally mature * Age 18 to 80 years at the time of surgery * Failure to respond to at least 3 months of non-operative treatment (e.g., bed rest, physical therapy, medication, nerve block, manipulation, or transcutaneous electrical nerve stimulation) * Ability to provide written informed consent after receiving adequate explanation of the study Exclusion Criteria: * Prior spinal surgery at the target or adjacent intervertebral level, except for decompression procedures such as discectomy * Inability to complete both investigational device implantation and posterior fixation in a si…