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Several conditions present with signs and symptoms that can mimic degenerative cervical myeloradiculopathy. This article delineates the “differential diagnosis” to be considered by every patient before signing up for cervical spine surgery. For any patient, surgery remains an option if and only if it is performed after satisfying appropriate indications and excluding other non-operative conditions.
Back and neck pain is the most common cause in the U.S. for days off of work. Only a small percentage of conditions related to neuropathic cervical pain (9-10%) require surgical treatment. The diagnosis of a disease process best treated by surgery can be a complex task. In any medical field, many disease states with a whole host of signs and symptoms can confound what initially appears to be a straightforward diagnosis. Considerations leading to cervical spine surgery are no different. Important aspects to consider in the diagnosis of cervical pain syndromes include the onset, location, timing, and the nature of the pain; associated aggravating and alleviating factors; the presence or absence of neurologic deficits; the presence or absence of axial pain (pain involving the cervical segments); and signs and symptoms associated with systemic diseases. This is not meant to be an exhaustive treatise on the differential diagnosis of degenerative cervical myeloradiculopathy (DCM); that is beyond the scope of this article. Rather, I hope it functions as a “laundry list” of conditions commonly misdiagnosed as DCM resulting from cervical spine arthritis that you, as an educated patient and consumer of health care, have explored with your treating physicians before undergoing unnecessary, unindicated surgery with inherent risks.
Degenerative cervical myeloradiculopathy is characterized by neck and radicular arm pain, weakness, numbness, gait difficulty, muscle wasting, coordination problems, spasticity, and bowel/bladder issues. The following disease entities share some of these signs and symptoms and must be ruled out by history, physical examination, and appropriate laboratory and diagnostic testing before they can be assumed to be due to DCM alone:
- Shoulder osteoarthritis/rotator cuff injury: The most common imitator of DCM, focal shoulder pain that is exacerbated by attempting to scratch your back is due to shoulder disease until proven otherwise. A shoulder exam should be included in all evaluations of neck and arm pain.
- Facet mediated pain: Although lower cervical pain is related to the joints of the lower cervical spine and is usually focal and limited to the neck, referred pain (pain felt somewhere else in the body than at its actual source) can radiate down the arm just like radiculopathy. Selective facet blocks can be both therapeutic and diagnostic.
- Unrecognized trauma: Pain associated with disc and/or ligament injury can lead to translational instability, producing transient nerve root and spinal cord compression resulting in symptoms of DCM. Flexion-extension x-rays are indicated in every patient pre-operatively. Vertebral arterial dissection (a tear along the inside wall of the artery that enlarges and blocks off normal blood flow) as a result of trauma is a rare but a serious condition that commonly presents with severe pain and neurologic deficits. Syringohydromyelia (degenerative cavitation of the spinal cord) is a chronic result of trauma; it can also be associated with abnormalities of the skull base, water on the brain (hydrocephalus), as well as the result of spinal tumors. It usually presents with poorly localized pain and progressive myelopathy.
- Degenerative ligamentous instability: The rationale is the same as in decompressive surgery would only make the instability worse. Progression of scoliosis can lead to narrowing of neural foramina, resulting in cervical radiculopathy.
- Peripheral neuropathy: Carpal tunnel syndrome presents with wrist and hand pain and paresthesias extending into the thumb, index, and middle fingers that can extend proximally as well. Ulnar neuropathy characteristically involves pain in the region of the elbow with weakness of the hand muscles and numbness of the ring and little fingers. Diagnosis depends on EMG.
- Brachial plexus pathology: The brachial plexus is the normal anatomic network of nerve trunks that intertwine in the upper armpit after the cervical nerve roots exit from the spine. The brachial plexus can be affected by trauma, tumors, etc., resulting in pain and symptoms similar to cervical radiculopathy. The result is abnormal functioning of the plexus referred to as a brachial plexopathy.
- Parsonage-Turner syndrome: A brachial plexopathy due to inflammation, usually the result of a virus.
- Thoracic outlet syndrome: A brachial plexopathy due to compression of the lower aspects of the plexus by abnormal ligaments, an extra rib, or vascular structures in the lower neck. Again symptoms similar to a cervical radiculopathy is the result.
- Systemic diseases: These are diseases that affect the entire body at once and include entities like fibromyalgia, rheumatoid arthritis, ankylosing spondylosis, systemic lupus erythematosus, painful polyneuropathies (affecting multiple peripheral nerves), etc. Patients often complain of stiffness, primarily in the morning.
- Cardiac pain: Typically radiating down the left arm and associated with substernal pressure, angina is the result of insufficient cardiac blood flow and should be evaluated on an emergent basis.
- Inflammatory and autoimmune conditions of the spinal cord and nerves: Usually due to autoimmune diseases or initiated by viral infections, these would include transverse myelitis, inflammatory neuropathies, paraneoplastic effects as a result of a tumor elsewhere in the body, etc. Viruses like HIV can affect the cervical spinal cord directly, presenting with a myelopathy syndrome. Guillain-Barre syndrome is an autoimmune disease the produces rapid onset of weakness due to demyelination of the nerve roots and peripheral nerves. Other autoimmune conditions presenting with weakness include myasthenia gravis, Eaton-Lambert syndrome, and polymyositis/dermatomyositis. These are beyond the scope of this article.
- Degenerative conditions of the spinal cord cells and nerve fibers tract: These include diseases such as multiple sclerosis, amyotrophic lateral sclerosis (ALS), severe vitamin B12 deficiency, spinal muscular atrophy, and cerebellar degeneration syndromes. Although typically painless, the signs, symptoms, and neurologic findings of ALS can be amazingly similar to those of degenerative cervical myelopathy.
- Pancoast tumor (superior pulmonary sulcus tumor): Due to involvement of the lower brachial plexus and C8/T1 nerve roots, metastatic lung cancer can present with radicular arm pain, hand weakness and atrophy, and hand numbness.
- Spinal cord and spinal canal tumors, metastatic tumors of the cervical spine: See the articles which discuss these tumors in greater detail elsewhere on Wascherspineinstitute.com. Localized pain at night and in the recumbent position are highly characteristic of tumors affecting the cervical vertebral column. Rare aggressive primary tumors affecting the vertebra of the cervical spine include multiple myeloma, chondrosarcoma, chordoma, and lymphoma. Benign tumors include osteochondromas, osteoblastoma, osteoid osteomas, giant cell tumors, eosinonophilic granulomas, hemangiomas, and aneurysmal bone cysts.
- Post-sternotomy syndrome: Retraction of the divided sternum during cardiac surgery can result in traction on the C8 nerve resulting in a pain syndrome identical to a C8 cervical radiculopathy.