Definition:
Cervical radiculopathy is a disease process marked by nerve compression from herniated disk material or arthritic bone spurs. This impingement typically produces neck and radiating arm pain or numbness, sensory deficits, or motor dysfunction in the neck and upper extremities.
Cervical radiculopathy occurs with pathologies that cause symptoms on the nerve roots. Those can be compression, irritation, traction, and a lesion on the nerve root caused by either a herniated disc, foraminal narrowing, or degenerative spondylotic change (Osteoarthritic changed or degeneration) leading to stenosis of the intervertebral foramen.
Most of the time cervical radiculopathy appears unilaterally, however it is possible for bilateral symptoms to be present if severe bony spurs are present at one level, impinging/irritating the nerve root on both sides. If peripheral radiation of pain, weakness, or pins and needle are present, the location of the pain will follow back to the concerned affected nerve root.
The human body has 8 cervical nerve roots, for 7 cervical vertebrae and this may seem confusing at first. However a nerve root comes out of the spinal column between C7 and T1, hence C8 as T1 already exists. Tanaka N. et al used a surgical microscope to do an anatomic study of the cervical intervertebral foramina, nerve roots, and intradural rootlets. The intervertebral foramina were shaped like a funnel with the entrance zone being the most narrow part. This was considered the place where the compression of the nerve roots in the intervertebral foramina occurs. Compression of the roots at the anterior side was ascribed to protruding discs and osteophytes of the uncovertebral region. Compression on the posterior side was caused by the superior articular process, the ligamentum flavum, and the periradicular fibrous tissues.
Nerve roots and the local vessels lack a perineurium and have a poorly developed epineurium, making them vulnerable to mechanical injury when compared to the periphery. The blood supply is also less secured and vulnerable to ischemic damage[5]. These anatomical differences to peripheral nerves may explain why low pressures on the nerve root elicit large changes and signs and symptoms. The nerve roots are vulnerable to pressure damage which is why small impingements can cause signs and symptoms.At 5-10mmHg (0.1psi) capillary stasis and ischemia has been observed with partial blockage of axonal transport. At 50mmhg tissue permeability increases with an influx of oedema, higher than 75mmhg, there is nerve conduction failure if sustained for 2 hours. At 70+mmHg neural ischemia is complete and conduction is not possible[5]. It is rare to get pressures that high but 5-10mmhg is a large small amount of pressure and signs and symptoms occur[5]. These pressures can occur with a less severe clinical picture in unique circumstances, if the pressure is acute then symptoms are severe however if chronic the nervous tissue is given time to adapt and evolve to the surrounding structure and symptoms are less severe.
Etiology:
The two main mechanisms of the nerve root irritation or impingement are:
- Spondylosis leading to stenosis or bony spurs - more common in older patients
- Disc herniation - more common in younger patients
Mechanical compression from spondylosis can affect the neuroforamen from all directions, which limits nerve root excursion. Cytokines released from damaged intervertebral discs can also cause this disorder. There is increasing evidence that inflammation itself and/or in association with root compression is the main cause of symptoms and signs. This is proved by the presence of interleukins and prostaglandin in herniated discs and the spontaneous recovery within weeks or months in the majority of patients. The most common level of root compression is C7 (reported percentages 46.3–69%), followed by C6 (19–17.6%); compression of roots C5 (2–6.6%), and C8 (10– 6.2%) are less frequent. One possible explanation is that intervertebral foramina are largest in the upper cervical region and progressively decrease in size in the middle and lower cervical areas, with an exception of the C7-Th1 foramen (C8).
Upper limb movements that are affected:
- C1/C2- Neck flexion/extension
- C3- Neck lateral flexion
- C4- Shoulder elevation
- C5- Shoulder abduction
- C6- Elbow flexion/wrist extension
- C7- Elbow extension/wrist flexion
- C8- Thumb extension
- T1- Finger abduction
The absence of radiating pain does not exclude nerve root compression. The same appears with sensory and motor dysfunction that might be present without significant pain.
Symptoms are generally amplified with movements that may be unidirectional or multidirectional reduce the space available for the nerve root to exit the foramen causing impingement [2]. This often causes the patient to present with a stiff neck and a decrease in cervical spine ROM, secondary musculoskeletal problems, decrease in muscle length of the cervical spine musculature (upper fibres of trapezius, scaleni, levator scapulae), weakness, joint stiffness, capsule tightness, and postural defects which can go on to affect movement mechanisms of the rest of the body.
Diagnosis:
- MRI
- EMG + Nerve Conduction Studies
- Spinal CT
Examination:
- Spurlings Test
- Upper limb tension-1
- Distraction test
Physical Therapy Management:
Although a definitive treatment progression for treating cervical radiculopathy has not been developed, a general consensus exists within the literature that using manual therapy techniques in conjunction with therapeutic exercise is effective in regard to increasing function, as well as active range of movement (AROM), focusing on decreasing levels of pain and disability will most likely be the main focus of the patient. Recent high level research confirms the positive outcomes of exercise therapy. If the patient has had long-term pain, an element of pain sensitisation may have developed and chronic pain behaves differently to acute pain. Therefore education about pain and reconceptualisation may be necessary.
Treatment Options:
- Education and advice
- Manual Therapy - PAIVMs (Passive Accessory Intervertebral Movements) / PPIVMs (Passive Physiological Intervertebral Movements) / NAGs (Natural Apophyseal Glides) / SNAGs (Sustained Natural Apophyseal Glides)
- Exercise Therapy - AROM, stretching and strengthening
- Postural re-education