The Diagnostic Sensitivity for Ulnar Neuropathy at the Elbow Is Not Increased by Addition of Needle EMG of ADM and FDI When Nerve Conduction Studies Are Normal

Electrodiagnostic studies and new diagnostic modalities for evaluation of peripheral nerve disorders

Electrodiagnostic studies (EDx) are frequently performed in the diagnostic evaluation of peripheral nerve disorders. There is increasing interest in the use of newer, alternative diagnostic modalities, in particular imaging, either to complement or replace established EDx protocols. However, the evidence to support this approach has not been expansively reviewed. In this paper, diagnostic performance data from studies of EDx and other diagnostic modalities in common peripheral nerve disorders have been analyzed and described, with a focus on radiculopathy, plexopathy, compressive neuropathies, and the important neuropathy subtypes of Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), vasculitic neuropathy and diabetic neuropathy. Overall EDx retains its place as a primary diagnostic modality in the evaluated peripheral nerve disorders. Magnetic resonance imaging and ultrasound have developed important complementary diagnostic roles in compressive and traumatic neuropathies and atypical CIDP, but their value is more limited in other neuropathy subtypes. Identification of hourglass constriction in nerves of patients with neuralgic amyotrophy may have therapeutic implications. Investigation of radiculopathy is confounded by poor correlation between clinical features and imaging findings and the lack of a diagnostic gold standard. There is a need to enhance the literature on the utility of these newer diagnostic modalities.

EMG und Neurografie – ein Update

Elektromyografie (EMG) und Elektroneurografie (ENG) gelten als bewährte Methoden, deren Anfänge aber schon Jahrzehnte zurückliegen. In dieser Arbeit werden jüngere Entwicklungen beschrieben und die Rolle von EMG und ENG in wichtigen Situationen diskutiert, nämlich bei traumatische Nervenläsionen, Nervenkompressionssyndromen, Polyneuropathien, Motoneuronerkrankungen, Myopathien, neuromuskulären Transmissionsstörungen und bei muskulärer Überaktivität.

A retrospective study of electrodiagnostically evaluated ulnar neuropathies with special guidelines for ulnar neuropathies at elbow

Background

The diagnosis of type, severity of ulnar neuropathy based on symptoms and clinical tests are unsatisfactory. This study aimed to retrospectively analyze ulnar neuropathies at different sites evaluated through electrodiagnostic studies (EDx), especially for ulnar neuropathy at elbow (UNE).

Results

Total 270 ulnar neuropathy patients’ data were recruited from laboratory record over a five-year period (2016–2021).Their demographic data, clinical history and EDx parameters were analyzed focusing on etiology, nerve lesion types, 5th-digit sensory, dorsal ulnar cutaneous nerve (DUCN) conduction, motor nerve conduction velocity (NCV) across elbow along with EMG of ADM, FDI, FCU, FDP muscles. The patients grouped into traumatic injuries—27.8% (T) and 72.2% non-traumatic (NT) had varied sensory-motor symptoms: pain—10%, altered sensation—28.1%, pain-paresthesia—14.8%, atrophy—25.2% and clawing—8.9%. UNE was the most prevalent (82.75%-NT, 66.67% -T) with < 50 m/s motor and sensory NCV across elbow. Compound muscle action potential (CMAP) amplitude > 50% drop across elbow was seen in 55.17%-NT and 54.16%-T groups. Abnormal DUCN and short-segment inching NCV were less frequently noted. In EMG, ADM (T-83.33% and NT-65.51%) and FDI (T-70.83% and NT-68.96%) muscles were evaluated the most and FDP the least.

Conclusion

UNE was the most common followed by forearm and wrist. NCV and CMAP across elbow are stronger EDx parameters for UNE. Neuropathy was irrespective of gender and prevalent at early of middle age. The EDx could be considered as one of the most valuable tests in confirming the localization, severity and type of ulnar nerve lesion, which favors management and prognosis of patient.