Inclusion:  patients between 40 - 100 years. No improvement despite nonsurgical treatment for more than 3 months. No history of lumbar fusion surgery. Single or double-level lumbar foraminal stenosis with corresponding leg pain  Exclusion:  Severe neurological deficit (motor grade less than Grade III) Combined inflammatory joint disease Combined neurodegenerative disease such as Parkinson's disease or dementia * Combined cancer, traumatic fracture Marked spinal deformity (C7 sagittal vertical axis > 10cm)