The initial purpose of the consultation and physical examination of the patient with a musculoskeletal complaint is to determine the pain generating structures. Historically there are many physical examination tests and procedures that have been developed and passed down from one clinician to another in the academic and clinical settings without systematic evaluation of validity[7, 10].
While advanced testing such as MRI and electrodiagnostics have not been shown to be valid stand-alone diagnostic procedures, they can contribute to diagnostic accuracy [11–13]. However, due to the high cost and sometimes invasive nature of these tests there is great benefit in having the ability to accurately diagnose musculoskeletal conditions via low cost and time efficient consultation and physical exam.
As such, diagnostic criteria are being developed for certain conditions. Cervical radiculopathy has been defined as an impingement or inflammatory irritation of the cervical spine nerve root most commonly caused by cervical spondylosis or intervertebral disc herniation resulting in pain radiating along neural pathways of the upper extremity[5]. Historically, nerve root compression was indicated by abnormal muscle strength, deep tendon reflexes or dermatomal sensation. However, many patients are neurologically intact yet present with cervical radiculopathy symptoms due to inflammatory irritation of the nerve root. For these patients a different set of sensitive tests is required.
Recently Wainner et al. defined a group of clinical exam tests that could identify with 90% probability the likelihood of the presence of cervical radiculopathy[6]. The tests shown to be most useful for indicating cervical radiculopathy were the upper limb tension test, ipsilateral cervical rotation less than 60 degrees, neck distraction test and Spurling test[6]. Rubinstein et al, also recently completed a systematic review of the diagnostic accuracy of physical exam tests for cervical radiculopathy. They concluded that Spurling, neck distraction, Valsalva and upper limb tension tests are most useful in establishing a diagnosis of cervical radiculopathy in patients without neurological deficits[10].
The patient in this case report had positive Spurling, neck distraction and upper limb tension tests. In addition, arm abduction decreased the symptoms and palpation of C4–6 on the right reproduced the chief complaint along the lateral arm and forearm. [See Figure 1] The combination of these findings contributed to the chiropractor's confidence in a diagnosis of cervical radiculopathy and the decision to proceed with conservative therapy.
Subsequent treatment was designed to locally decrease the irritation of the involved nerve root and globally improve postural and segmental spinal biomechanics. A passive treatment protocol involving manipulation of the cervical and thoracic spine and manual cervical distraction, which has previously been shown to be effective for cervical radiculopathy, was initiated[16, 18].
Within several treatments the patient began to experience a decrease in the intensity of the upper extremity symptoms. She was then also instructed on an active cervicobrachial neuromobilization technique which has been suggested can break perineural adhesions resulting from an inflammatory response in conditions such as cervical radiculopathy, thus aiding the healing process [16, 17].
When the patient presented the second time to the chiropractor complaining of right upper extremity symptoms she also had the results of a cervical MRI completed three months prior demonstrating foraminal encroachment at C5–6 on the right.
However, this time the chiropractor was unable to reproduce the chief complaint with the same physical exam tests as previously performed. Each of the cervical radiculopathy tests; Spurling's cervical compression, cervical distraction, arm abduction and upper limb tension, was negative. The patient was also neurologically intact with regard to muscle strength and deep tendon reflexes. The chief complaint was only reproduced by palpation of a trigger point in the right infraspinatus muscle [See Figure 2].
Myofascial trigger points have been defined as hyperirritable loci within taut bands of skeletal muscle that can produce local and referred pain[19]. Sciotti el al, have demonstrated that trigger points of the upper trapezius muscle can be reliably localized by a clinician using manual palpation[20].
While the MRI revealed anatomical changes consistent with potential causes of cervical radiculopathy, given the lack of clinical findings suggesting such, it is unlikely that the nerve root was compressed, irritated or inflamed during the second episode and therefore not the cause of symptoms. Because the pain patterns of a C6 cervical radiculopathy and infraspinatus trigger point are similar (See Figures 1 and 2), confusion can result if the clinician bases the diagnosis solely on imaging results and symptomology. Both must be correlated with the physical exam findings.
The differential diagnosis of radicular and referred myofascial pain is also complicated by the variable nature of pain patterns. Travell stated that pain referred from myofascial trigger points does not follow a simple pattern and may not always occur within the same dermatome, myotome or sclerotome[19]. Also, Bove et al. recently reported that radicular pain symptoms are perceived in deep structures rather than on the skin and that myotomal or sclerotomal patterns may be more diagnostic than traditional dermatomal charts[21].
In this case it is possible that the patient was presenting at different stages of functional pathology along a cervical radiculopathy continuum. The first episode may have represented a true nerve root irritation that was confirmed with provocative testing of the cervical spine. However, the second episode may have represented an earlier stage of cervical radiculopathy that while still causing neuropathic symptoms, may not be detected on physical examination if the irritation of the nerve root has not reached a certain threshold. It is unknown if the myofascial trigger point in the infraspinatus muscle in the second episode was a result of postural and biomechanical faults of the scapulothoracic region or if, given the infraspinatus muscle is innervated by the suprascapular nerve with contribution from the C5 and C6 nerve roots, that the muscle becomes hyperirritable due to nerve root compromise at these levels.
During the patient's second episode, she was treated with manual digital pressure to the trigger point as well as cervical distraction and spinal manipulation, so there was some duplication of treatment with the earlier acute radiculopathy. However, given the rapid response to treatment during the second episode compared with the first, it appears that the trigger point was the primary source of symptoms.