Research Review By Dr. Michael Haneline©

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Date Posted:

June 2019

Study Title:

Diagnostic accuracy of upper limb neurodynamic tests for the assessment of peripheral neuropathic pain: A systematic review

Authors:

Koulidis K, Veremis Y, Anderson C & Heneghan N

Author's Affiliations:

School of Sport, Exercise & Rehabilitation Sciences, University of Birmingham, UK.

Publication Information:

Musculoskeletal Science and Practice 2019; 40: 21-33.

Background Information:

Pain resulting from a lesion or disease of the somatosensory nervous system may be referred to as peripheral neuropathic pain (PNP). PNP occurs following injury, compression, inflammation or ischemia to a peripheral nerve trunk or nerve root and produces symptoms and signs of neuropathy.

Entrapment neuropathies (EN), such as carpal tunnel syndrome and cervical radiculopathy, comprise the most common conditions that affect the peripheral nervous system. ENs have been reported to affect 2–15% of workers with associated financial costs exceeding 2 billion dollars each year in the USA.

The diagnosis of EN is based on information gathered during history taking and physical examination, which is often confirmed via electrophysiological studies and/or diagnostic imaging. Confirmatory diagnostic imaging and electrophysiological studies, however, are costly and may involve prolonged waiting times for patients; thus, it would be useful to establish accurate clinical examination tests for diagnosing EN.

Neurodynamic tests attempt to identify changes in mechanosensitivity which are affected by the mechanical, electrical and chemical properties of the nervous system. Structures surrounding the nerves can apply mechanical or chemical stimuli with consequential venous congestion, impaired axoplasmic flow, inflammation and the development of mechanosensitivity.

The objective of upper limb neurodynamic tests (ULNTs – often referred to as upper limb nerve tension tests as well) is to put stress on the neurological structures of the upper limb, analogous to what occurs during straight leg raise testing. The shoulder, elbow, forearm, wrist and fingers are sequentially placed in specific positions such that stress is placed on the tested nerve.

A neurodyamic test is considered positive if it can reproduce the patient's symptoms and if those symptoms can be altered through structural differentiation.

Four ULNTs have been developed to assess mechanosensitivity of the brachial plexus, median (ULNT1 and ULNT2a), radial (ULNT2b) and ulnar nerve (ULNT3) (1). They are performed as follows, with the patient seated or supine (movements listed in the order in which they are to be performed/facilitated):
  • ULNT1 (median): shoulder depression, shoulder abduction to 100º, wrist and fingers extension, forearm supination, shoulder lateral rotation, elbow extension, contralateral lateral bending of cervical spine.
  • ULNT2a (median): shoulder depression, elbow extension, lateral rotation of the arm, wrist and finger extension, shoulder abduction 10º, contralateral lateral bending of the cervical spine.
  • ULNT2b (radial): shoulder depression, elbow extension, medial arm rotation, wrist and fingers flexion, shoulder abduction, contralateral lateral bending of the cervical spine.
  • ULNT3 (ulnar): shoulder depression, shoulder abduction 100º, lateral rotation of the arm, forearm pronation, elbow flexion, wrist and fingers extension, contralateral lateral bending of the cervical spine.
The reliability of ULNTs has been investigated and found to generally have moderate reliability, (2) with almost perfect reliability for the interpretation of the ULNT1 (median) and ULNT2b (radial). On the other hand, the diagnostic accuracy (i.e. validity) of ULNTs has not yet been fully established.

The purpose of this study was to review the literature to ascertain the level of diagnostic accuracy for ULNTs when compared to diagnostic imaging and/or electrophysiologic studies, and how the results from ULNTs can be interpreted when assessing patients with arm and/or neck symptoms.

Pertinent Results:

A literature search produced eight studies that were included in the review which involved a total of 579 subjects. Four of the included studies were deemed to be of low risk of bias, even though there were concerns about their applicability.

Five of the studies examined the diagnostic accuracy of ULNTs in patients with suspected carpal tunnel syndrome, although two of them were at risk of bias and there were concerns about the applicability of four of them.

Three studies compared ULNT1 with a reference standard (NCS and needle electromyography) in patients with suspected cervical radiculopathy. The validity of ULNT2b (radial) was assessed in two studies, with one of them also considering the diagnostic accuracy of ULNT2a (median), ULNT3 (ulnar) and ULNTs combined as a single test.

For carpal tunnel syndrome, ULNT1 sensitivity ranged from 0.4 to 0.93, specificity from 0.13 to 0.93, positive likelihood ratio from 0.86 to 3.67 and negative likelihood ratio from 0.5 to 1.9.

For cervical radiculopathy, ULNT1 and the combined use of four ULNTs had sensitivity of 0.97, with the ULNT3 (ulnar) being the most specific at 0.87. The positive likelihood ratio ranged from 0.58 to 5.68 and negative likelihood ratio from 0.12 to 1.62.

Clinical Application & Conclusions:

The quality of existing studies on the use of ULNTs reviewed by these authors was found to range from low to very low. Therefore, the authors recommended that more studies that are of higher quality are needed to establish firm conclusions on the use of ULNTs.

At this time, the authors concluded that the available evidence does not support the use of ULNTs as stand-alone tests for the diagnosis of carpal tunnel syndrome. However, based on limited evidence, ULNTs may be clinically useful in forming a diagnosis of cervical radiculopathy, but primarily as a “ruling out” strategy (that is, if the tests are negative, they can help rule out a cervical radiculopathy).

EDITOR’S COMMENT: This paper is in line with much of the evidence on orthopedic and physical examination procedures – specifically the idea that no one test can be solely relied upon to inform any diagnosis. Clinicians should always employ these (and other) tests with strong consideration of the totality of a patient’s presentation, history and other physical examination findings. ULNTs, based on existing evidence, are best used to assist in ruling out cervical radiculopathy, as mentioned above.

Study Methods:

This was a well-done systematic review that was conducted according to a protocol described in the Cochrane Handbook for Diagnostic Test Accuracy. Six databases were searched using a comprehensive list of search terms.

The criteria for inclusion of studies were as follows:
  • patient population experiencing arm and/or neck symptoms with suspected peripheral neuropathic involvement;
  • studies that compared ULNTs to a reference standard; and
  • a study design that used primary diagnostic accuracy data.
Exclusion criteria:
  • case series, case reports, surgical or cadaveric studies; and
  • publications for which full text were not available.
Risk of bias was assessed by 2 reviewers working independently using QUADAS-2 instrument and the overall quality of evidence was evaluated using the GRADE rating system.

The outcomes of interest were sensitivity, specificity, likelihood ratios (LR) and predictive values (PV), as well as true positive, false positive, true negative and false negative values which had to be calculated by the authors from incomplete or raw data in some cases.

Sensitivity and specificity were classified as low (< 0.50), low/moderate (0.51-0.64), moderate (0.65-0.74), moderate/high (0.75-0.84) and high (> 0.85). Likelihood ratios were considered to indicate conclusive evidence when the LR was + > 10 or - < 0.1), strong diagnostic evidence when the LR was + 5 to 10 or - 0.1 to 0.2, weak diagnostic evidence when the LR was +2 to 5 or - 0.2 to 0.5, and negligible evidence when the LR was + 1 to 2 or - 0.5 to 1.

Study Strengths / Weaknesses

This systematic review was well-done, effectively following the strict Cochrane Review protocol. While the authors did exceptional work, they could find very few studies to include in the review. Furthermore, the included studies were generally of low quality which limited their ability to draw firm conclusions.

Additional References:

  1. Elvey R. 1980. Brachial plexus tension tests and the pathoanatomical origin of arm pain. In: Idczak, R. (Ed.), Aspects of Manipulative Therapy. Lincoln Institute of Health Sciences, Melbourne, pp. 105–110.
  2. Schmid A, Brunner F, Luomajoki H, et al. Reliability of clinical tests to evaluate nerve function and mechanosensitivity of the upper limb peripheral nervoussystem. BMC Muscoskelet Disord 2009; 10 11-2474-10-11.
  3. Wainner R, Fritz J, IrrgangJ, et al. Reliability and diagnostic accuracy of the clinical examination and patient self-report measures for cervical radiculopathy. Spine 2003; 28(1): 52–62.