By Shawn Thistle
Localized shoulder pain can be difficult to diagnose and manage, owing to the potential for the source of pain to be either the shoulder or a cervical nerve root.
|Study title: Arm squeeze test: a new clinical test to distinguish neck from shoulder pain
Authors: Gumina S, Carbone S, Albino P et al.
Publication information: European Spine Journal 2013; 22: 1558-1563.
Localized shoulder pain can be difficult to diagnose and manage, owing to the potential for the source of pain to be either the shoulder or a cervical nerve root. Additionally, the fact that neck and shoulder conditions are often concomitant during advanced age and share common innervation and musculature increases the challenge for treating clinicians. There is currently no specific test that can assist practitioners with differential diagnosis to discern between shoulder pain of shoulder and neck origin.
The authors of this study developed a simple clinical test that would assist in the differential diagnosis of shoulder pain and help to differentiate between shoulder pain of neck and local origin. They hypothesized that squeezing the middle third of the upper arm (brachial biceps and triceps area), on the affected side, with a strength necessary to have a moderate compression of skin, subcutis and muscle, would elicit an intense reaction of local pain only in patients with cervical nerve root compression from C5 to T1, and not in those where the pain arises from the shoulder itself. The proposed test is based on the anatomic rationale that in the middle third of the arm, the musculocutaneous nerve (cervical root from C5 to C7), the radial nerve (from C5 to T1), the ulnar nerve (from C7 to T1) and the median nerve (from C5 to T1) are relatively superficial and it is therefore easy to obtain a painful provocation response by squeezing the arm with a moderate compression.
A total of 1,567 patients presenting with shoulder pain were tested (in addition to a control group composed of 350 subjects without shoulder pain).
Diagnoses included: posterosuperior rotator cuff tear (n = 903), primary (unrelated to trauma and/or surgery) shoulder adhesive capsulitis (n = 155), degenerative arthropathy of the acromioclavicular (AC) joint (n = 101), calcifying tendonitis of the shoulder (n = 55), glenohumeral arthritis grade I–II (n = 48) and a group of patients with cervicogenic shoulder pain (n = 305).
The arm squeeze test was positive in 295 out of 305 (96.7 per cent) patients with subsequently confirmed cervical nerve root compression (C5-T1), compared with those diagnosed with rotator cuff tear (35/903, or 3.87 per cent), adhesive capsulitis (3/155 or 1.93 per cent), AC arthritis (0 per cent), calcifying tendonitis (1/55 or 1.81 per cent) and glenohumeral arthritis (4/48 or 8.33 per cent) [p < 0.001]. Further, a positive result was elicited in only four per cent (14/350) of control patients.
The inter-observer k value was r = 0.81 (0.79–0.82); the intra-observer k value was r = 0.87 (0.85–0.89). Sensitivity was 0.96; specificity ranged from 0.91 to 1; positive prognostic value ranged from 0.89 to 1; negative prognostic value ranged from 0.81 to 0.99; likelihood ratios for an abnormal test result ranged from 10.6 to 48; and likelihood ratios for a normal test result ranged from 0.04 to 0.44.
Conclusions and practical application
The Bone and Joint Decade Task Force on neck pain determined that routine clinical examination is more effective in ruling out cervical radiculopathy than in confirming its presence and concluded that a combination of history, physical exam, imaging techniques and, potentially, needle EMG were considered the gold standard to properly diagnose conditions of cervical radiculopathy. The authors determined that the arm squeeze test results in patients diagnosed with cervical nerve root compression differed significantly from those in normal individuals and those in patients diagnosed with shoulder pathologies. The positivity of the test indicates the examined patients are more likely to have cervical nerve root compression.
Current tests such as Spurling’s test or brachial plexus tension tests can be useful in determining the source of radicular pain. However, these tests are specific for cervical spine disease and often occur after an examination of neck motion, which includes flexion-extension, lateral rotation and lateral bending. The proposed arm squeeze test is quick and easy to perform and looks as if it can help determine the presence of nerve root irritation. The authors propose that the arm squeeze test is a viable and specific option for differential diagnosis of neck/shoulder pain. More research is needed to confirm this result, but clinicians can integrate this simple test into practice and monitor its effectiveness.
Dr. SHAWN THISTLE is the founder and president of Research Review Service, an online, subscription-based service to help busy practitioners integrate current, relevant, scientific evidence into their practice (www.researchreviewservice.com ). This article was submitted by Dr. Jeff Muir for Research Review.