Review Question - QID 219108

A 54-year-old man presents with 6 months of bilateral buttock and leg pain. He is an avid cyclist and has minimal pain while on a bike; however, he has severe pain when walking. Initial treatment including physical therapy, NSAIDS, and an epidural steroid injection provided only temporary relief. On physical exam he has normal motor strength in his lower extremities, negative straight-leg raise tests bilaterally, and palpable bilateral dorsalis pedis pulses. Figure A shows his lumbar flexion and extension views. A video of the axial and sagittal views of his lumbar MRI is attached. What is the most appropriate next step in management?