The logical choice of muscles for the needle-electromyography evaluation of cervical radiculopathy.

OBJECTIVE

To find the theoretically smallest subsets of muscles for needle-electromyography screening of cervical radiculopathies that meet or exceed the American Association of Electrodiagnostic Medicine (AAEM) guideline: ascertaining that each root and its adjacent roots are represented by at least 2 muscles each, innervated by those roots via different peripheral nerves.

DESIGN

Twenty-two and 36 muscle sets and their myotomal innervation were derived from the literature, and rearranged into 15 and 23 unique muscle groups by root and peripheral nerve innervation. All 2 circumflex 15 and 2 circumflex 23 subsets thereof were respectively identified. The best approximations that met or exceeded the AAEM criteria were computed for each subset and the smallest subsets that qualified were retained.

SETTING

Electromyography laboratory.

PARTICIPANTS

None.

INTERVENTION: Not applicable.

MAIN OUTCOME MEASURES: Compliance with or exceeding the AAEM guideline in the number of muscles sampled per damaged root and the number of muscles sampled per adjacent normal roots.

RESULTS

The smallest subsets satisfying or exceeding the AAEM guideline are of 8, 9, and 10 muscles each, and are enumerated in tables 3 and 4 in this article.

CONCLUSIONS

Electromyographers may choose a set or sets from tables in this article that best suits them, with confidence that they comply with or exceed the AAEM guideline while causing minimal pain to their patients and using the shortest possible procedure. All the roots can be screened at once to best differentiate between normal and damaged roots, and, in most cases, to reach a final diagnosis. Nonetheless, when needed, each set may be the basis for a more extensive workup.