2015 Young Investigator Award Winner: Cervical Nerve Root Displacement and Strain During Upper Limb Neural Tension Testing: Part 1: A Minimally Invasive Assessment in Unembalmed Cadavers

STUDY DESIGN

A cross-sectional cadaveric examination of displacement and strain measured at the level of the cervical nerve roots during upper limb neural tension testing (ULNTT) with median nerve bias.

OBJECTIVE

To determine the displacement and strain of cervical nerve roots C5-C8 during ULNTT with minimal disruption of surrounding tissues.

SUMMARY OF BACKGROUND DATA

Clinical examination of neural pathology involving cervical nerve roots is difficult because of the transient nature of pathologies, such as cervical radiculopathy, entrapment neuropathies, and thoracic outlet syndrome. Cadaveric studies have demonstrated significant displacement and strain in lumbosacral nerve roots during neurodynamic testing of the lower extremity. Examination into the biomechanical behaviors of cervical nerve roots during ULNTT has not been performed.

METHODS

Eleven unembalmed cadavers were positioned supine as though undergoing ULNTT. Radiolucent markers were implanted into cervical nerve roots C5-C8. Posteroanterior fluoroscopic images were captured at resting and ULNTT positioning. Images were digitized and displacement and strain were calculated.

RESULTS

ULNTT resulted in significant inferolateral displacement (average, 2.16 mm-4.32 mm, P < 0.001) of cervical nerve roots C5-C8. There was a significant difference in inferolateral displacement between the C5 and C6 nerve roots (3.15 mm vs. 4.32 mm, P = 0.009). ULNTT resulted in significant strain (average, 6.80%-11.87%, P < 0.001) of cervical nerve roots C5-C8. There was a significant difference in strain between the C5 and C6 nerve roots (6.60% vs. 11.87%, P = 0.03).

CONCLUSION

ULNTT caused significant inferolateral displacement and strain in cervical nerve roots C5-C8. These results provide the mechanical foundation for the use of ULNTT in clinical evaluation of pathology in the cervical region, such as in cervical radiculopathy, entrapment neuropathies, and thoracic outlet syndrome.

LEVEL OF EVIDENCE

2.

Can testing of six individual muscles represent a screening approach to upper limb neuropathic conditions?

BACKGROUND

It has previously been demonstrated that an extensive upper limb neurological examination of individual muscle function, sensation in homonymous innervated territories, and nerve trunk allodynia is reliable and that the outcome reflects symptoms. Since this approach may appear complicated and time consuming, this study deals with the value of an examination limited to manual testing of only six muscles.

METHODS

Two examiners blinded to symptom status performed manual muscle testing of six muscles in 82 upper limbs with or without pain, weakness, and/or numbness/tingling. The six muscles represent three antagonist pairs (pectoralis major/posterior deltoid, biceps/triceps, and radial flexor of wrist/short radial extensor of wrist). The inter-rater reliability of detecting muscular weaknesses and the relation of weakness to the mentioned symptoms were analysed by kappa-statistics.

RESULTS

The two examiners recognized weaknesses in 48 and 55 limbs, respectively, with moderate agreement (median kappa = 0.58). Out of these, 35 and 32 limbs, respectively, were symptomatic. There was good correlation between findings and symptoms for one examiner (kappa = 0.61) and fair correlation for the other one (kappa = 0.33). Both reached high sensitivity (0.92, 0.84) but less satisfactory specificity (0.70, 0.50). Weaknesses agreed upon by the two examiners correlated moderately with symptoms (kappa = 0.57).

CONCLUSIONS

Weakness in one or more muscles was present in almost all symptomatic limbs but in many non-symptomatic limbs as well. Manual testing of six muscles may represent a useful screening approach to upper limb neuropathic conditions, but a confirmative diagnosis requires further assessment.

Breast surgery and neural tissue mechanosensitivity

Arm pain is a complication following breast cancer surgery. This study examined the impact of breast surgery on the mechanosensitivity of upper quadrant neural tissues based on responses to a clinical provocation test. The responses of twenty patients to the ULTT 2a were recorded pre-operatively and six weeks post-operatively in terms of the available range of glenohumeral abduction and the area, nature and intensity of symptoms. The results indicated that there was a tendency towards increased neural tissue mechanosensitivity post-surgically, judged by a significant reduction in glenohumeral abduction range and a variance in symptoms in the operated arm. Unexpectedly, range of abduction reduced bilaterally suggesting that central as well as peripheral mechanisms may be involved in this response.

Pain and muscular responses to a neural tissue provocation test in the upper limb

Pain and muscular responses to a Neural Tissue Provocation Test with bias to median nerve were examined in 20 asymptomatic subjects. The test was performed on both arms with the cervical spine in a neutral position and in contralateral sideflexion as a sensitizing manoeuvre. The angle of elbow extension at the time of onset of pain and muscle activity in trapezius, biceps and triceps muscles was measured using an electrogoniometer. Muscle activity was recorded by surface electromyography. Results indicate that pain responses and muscle activity of trapezius are present in the majority of normal subjects. The onset of pain was highly reliable and compared favourably with detection of muscle activity onset. There was no significant difference of the angle of the elbow with the onset of pain between arms. Hence in patients with unilateral neck or upper limb pain a difference between sides might be indicative of a possible neural tissue involvement. Pain and muscular responses were influenced by the position of the cervical spine. This finding suggests that cervical contralateral sideflexion has a sensitizing effect on neural tissues. There was an association between the onset of pain and onset of trapezius muscle activity in all painful trials. However, muscle activity was also present in subjects with no pain.

Repetitive strain injury in computer keyboard users: pathomechanics and treatment principles in individual and group intervention

Computer users experience high rates of injury and disability, broadly termed repetitive strain injury (RSI). With more than 60 million Americans using computers in offices and homes, the potential magnitude of the RSI problem indicates a need for increased attention to prevention and treatment. The purpose of this article is to: 1) present a conceptual model of RSI as a kinetic-chain, multifactorial disorder; 2) outline the salient features of the clinical evaluation of the RSI patient; 3) describe the role of postural deviation in the pathogenesis of RSI; 4) present the principles of individual manual therapy; and 5) discuss the rationale, admission criteria, educational principles, and outcome of a multidisciplinary group intervention.

Physical evaluation of the peripheral nervous system in disorders of pain and dysfunction

In the clinical examination of a patient who is in pain, use can be made of the sensitization of a peripheral nerve to determine whether the disorder is neurogenic. Techniques of active and passive moment analysis, peripheral-nerve provocation tests, nerve palpation, and clinical reasoning are used in the evaluation. The technique is described and a case study is presented to support its use.