Cervical Radiculopathy
Cervical radiculopathy is caused by a cervical nerve root compression. The patient will present with pain and/or progressive neurological deficit that results from conditions such as disc herniation, which irritate a nerve in the cervical spine. So, cervical radiculopathy is an irritation of the cervical nerve root.
Cervical spine and shoulder problems often overlap, and therefore need to be differentiated. The condition is of cervical spine etiology if the patient’s symptoms are relieved by shoulder abduction, done by placing their hand over their head. This relief of symptoms with shoulder abduction occurs due to decreased tension on the nerve roots.
When conducting image studies, be aware of the false positive MRIs, especially if the patient is above the age of 40 years old. Nerve conduction studies are not useful, as they also have a high false negative rate. However, EMG and nerve studies may differentiate radiculopathy from peripheral nerve entrapment.
Cervical disc problems usually affect the lower numbered nerve root. For example, C5-C6 is the most commonly affected disc, and this will compress the C6 nerve root, and a C6-C7 disc herniation would affect the C7 nerve root.
There are seven vertebrae in the cervical spine, but there are eight nerve roots. The nerve roots run above the pedicle of the corresponding vertebrae. For example, the C7 nerve root runs above the pedicle of the C7 vertebrae. However, since there are 8 cervical nerve roots, the C8 nerve root runs above the T1 pedicle, and then the T1 nerve root runs below the T1 pedicle. Also, cervical nerve roots are horizontal in orientation. In this way, it does not matter if cervical disc herniation is central or foraminal in nature, it will compress the same nerve root.
If the patient has numbness of the middle finger, the C7 nerve is always affected. If the first two fingers, the thumb and index fingers, are affected, then C6 is the culprit. But, if the last two fingers, the ring and pinky fingers, are affected, then C8 is the problem. So, the C6 dermatome is present in the shape of the number 6, when the thumb and index finger touch at the tips. C7 dermatomes is the middle finger. Finally, the C8 dermatome is the last two fingers.
Nerve root C7 is responsible for wrist flexion and finger extension. This is the easiest to remember because when looking at the forearm with the wrist flexed, it forms the shape of a 7. The C7 nerve is also in charge of elbow extension and the triceps reflex. C 6 then controls the opposite forces of C7 for the wrist and elbow; it is responsible for wrist extension and elbow flexion. Then, opposite of finger extension controlled by C7, C8 is responsible for finger flexion. Finally, finger abduction and adduction are controlled by T1, meaning the interossei are controlled by T1.
The patient will present with unilateral arm pain that is relieved by elevation of the arm. They will also have paresthesia in specific dermatomes, depending on which nerve root is affected. The patient may also have an upper trapezius pain or interscapular pain. Another symptoms of cervical radiculopathy is an occipital headache.
When examining the patient, provocative tests such as the Spurling’s test and the shoulder abduction test should be done. The Spurling’s test is done by extending and rotating the neck towards the involved side. With a positive Spurling’s test, the symptoms will be reproduced by narrowing the neuroforamen. This test differentiates cervical radiculopathy from peripheral nerve entrapment. To perform the shoulder abduction test, the patient’s arm is lifted above the head, which should relieve the symptoms if the cervical nerve roots are affected. The shoulder abduction test differentiates cervical pathology from other causes of painful shoulder etiology.
Radiculopathy should be differentiated from myelopathy, and coexisting myelopathy should also be excluded. To do so, examine the patient for upper motor neuron signs or cervical myelopathy. Gait instability, Hoffman’s sign, Babinski reflex, ankle clonus, and hyperreflexia in the triceps and quadriceps all should be tested to test for cervical myelopathy versus radiculopathy. Double crush syndrome should also always be ruled out. This is nerve compression in the neck and also in the peripheral nerve.
Even if a severe cervical spine disc problem is seen on an MRI, it should be treated conservatively for at least 3 months, and the patient should be given physical therapy and nonsteroidal anti-inflammatory medications. 75% of patients will improve with non-operative treatment. Cervical radiculopathy is generally treated non-operatively, in contrast with cervical myelopathy. However, surgery is indicated for patients with cervical radiculopathy if they have persistent severe pain for 6–12 weeks and/or progressive neurological deficits, such as weakness or numbness. The surgical procedure to treat cervical radiculopathy is usually done anteriorly with direct removal of the lesion that causes the symptoms, such as a herniated disc or spurs. When the anterior bone graft or the allograft is placed in the disc space, the neuroforamen should be opened, which will indirectly relieve the nerve. Once the bone graft is in place, an anterior plate should be added.
