Cervical Disc Herniation with Cord Compression

A 54-year-old computer programmer presents with 4 months of progressive neck pain radiating into the left arm (C6 dermatome) with paresthesias and weakness in wrist extension. He reports difficulty buttoning shirts and an unsteady gait over the past 6 weeks. Examination reveals lower-limb hyperreflexia, bilateral upgoing plantars, positive Hoffmann's sign, and positive Lhermitte's sign. MRI cervical spine shows a large left paracentral posterior disc herniation at C5-C6 with focal T2 hyperintensity within the cord (myelomalacia). The structure marked **A** in the diagram is compressing the ventrolateral cord by approximately 40% of canal diameter. Which of the following is the most appropriate management for this patient?