Hi there. The instrumentation following cervical fusion could lead to neurological deficit due to metal plates and fibrosis leading to nerve impingement. This is the main cause for pain in left arm and hand. Consult your neurosurgeon for a recent MRI spine for any fresh changes. Physiotherapy, non steroidal anti inflammatory drugs and lastly a re look surgery are the options available. Take care.
Bout time for a tune up, so to speak