Effect of cervical contralateral lateral flexion on the median nerve and fascia at the wrist - Cadaveric study.

BACKGROUND: Neurodynamic tests are an essential aspect of the physical examination of the patient when suspicion of neural involvement exists. A manoeuvre that is hypothesised to move nerves differentially relative to other structures (structural differentiation) has been proposed as a necessary part of neurodynamic testing for differential diagnosis. However, although the specificity of structural differentiation for peripheral nerve over muscle has been demonstrated in some body regions, no study has tested specificity of nerve movement relative to fascia. OBJECTIVES: The aim of this study was to measure the effect of the cervical contralateral lateral flexion (CCLF) as an structural differentiation manoeuvre for the median nerve compared to fascia (superficial and deep) at the wrist during the upper limb neurodynamic test 1 (ULNT1). DESIGN: A cross-sectional study was performed in 5 fresh frozen cadavers. METHODS: Excursion and strain in the fascia (superficial and deep) and the median nerve were measured at the wrist with structural differentiation during the ULNT1. KINOVEA software was used to measure kinematic parameters. RESULTS: CCLF resulted in significant proximal excursion in the median nerve (p < 0.001*) but not in the strain. CCLF neither produced changes in strain nor excursion in the superficial and deep fascia (p > 0.05). CONCLUSION: This study showed that CCLF produced significant differential excursion in the median nerve at the wrist compared to the local superficial and deep fascia during the ULNT1. The data support CCLF in mechanical differentiation between nerve and fascia in this area in diagnosis of local sources of wrist pain.

Diagnostic accuracy of the upper limb neurodynamic test 1 using neurodynamic sequencing in diagnosis of carpal tunnel syndrome.

BACKGROUND: The upper limb neurodynamic test 1 is used in the diagnosis of median nerve neuropathies such as carpal tunnel syndrome but its diagnostic validity remains limited. Neurodynamic sequencing has been suggested to increase the specificity of the neurodynamic tests, however, to date, information on the diagnostic accuracy of this variation in neurodynamic testing is required. OBJECTIVES: The aim of this study was to analyze the diagnostic validity of the local sequence of ULNT1 (LS-ULNT1) (i.e. a sequence that begins at the joint where the problem is (wrist) and progressively moves joints further away from it), in the diagnosis of CTS. A secondary aim was to describe the location of sensory responses to this modified neurodynamic test sequence. DESIGN: A prospective diagnostic accuracy study was designed. METHOD: Nerve conduction studies were used as the gold standard. The LS-ULNT1 was performed in 58 consecutive patients (17 men, 44 women) with suspected CTS. RESULTS: Sensitivity of the LS-ULNT1 was 65.7% (CI 48.0-80.9%) and the specificity was 95.7% (CI 78.1-99.9%). The positive and negative likelihood ratios were >5 and < 0.5, respectively, indicating the ability of the test to generate small but sometimes important changes in post-test probability. CONCLUSIONS: The overall results of this study showed that the LS-ULNT1 could be useful in confirming the diagnosis of CTS. The test demonstrated high specificity and the +LR indicated the ability of the test to generate changes in posttest probability, especially with a positive LS-ULNT1 result.