The purpose of this study was to evaluate the usefulness of ultrasound in the preoperative workup of peripheral nerve lesions and illustrate how nerve ultrasonography can be integrated in routine clinical and neurophysiological evaluation and in the management of focal peripheral nerve injuries. The diagnostic role and therapeutic implications of ultrasonography for different neuropathies are described.
The authors analyzed the use of ultrasound in 119 entrapment, tumoral, posttraumatic, or postsurgical nerve injuries of limbs evaluated in 108 patients during 2013 and 2014. All patients were candidates for surgery, and in all cases the evaluation included clinical examination, electrodiagnostic studies (nerve conduction study and electromyography), and ultrasound nerve study.
Ultrasound was used to explore the nerve fascicular echotexture, continuity, and surrounding tissues. The maximum cross-sectional area (CSA) and the presence of epineurial hyperechogenicity or intraneural hyper- or hypoechogenicity, of anatomical anomalies, dynamic nerve dislocations, or compressions were recorded.
The concordance rate of neurophysiological and ultrasonographic data was analyzed, classifying ultrasound findings as confirming, contributive, or nonconfirming with respect to electrodiagnostic data. The correlation between maximum nerve CSA and neurophysiological severity degree in entrapment syndromes was statistically analyzed.
Ultrasonography confirmed electrodiagnostic findings in 36.1% of cases and showed a contributive role in the diagnosis and surgical planning in 53.8% of all cases; the findings were negative (“nonconfirming”) in only 10.1% of the patients. In 16% of cases, ultrasound was not only contributive, but had a key diagnostic role in the presence of doubtful electrodiagnostic findings. The contributive role differed according to etiology, being higher for tumors (100%) and for posttraumatic or postsurgical neuropathies (72.2%) than for entrapment neuropathies (43.8%).
Ultrasound is a powerful, noninvasive tool for the examination of peripheral nerve injuries, and can guide diagnosis of and surgical strategy for focal peripheral nerve injuries. It allows direct visualization of the cause and extent of nerve lesions and finds its place between electrodiagnostic tests and exploratory surgery. It can provide invaluable information, such as the presence and extent of a mass, scar compression, or neuromas. The authors recommend it as a complement to routine clinical and neurophysiological evaluation and as the first-line imaging modality for masses of suspected nerve origin.
ABBREVIATIONSCMAP = compound muscle action potential; CSA = cross-sectional area; EMG = electromyography; LSD = least significant difference; MUAP = motor unit action potential; SNAP = sensory nerve action potential.
FilippouGMondelliMGrecoGBertoldiIFredianiBGaleazziM: Ulnar neuropathy at the elbow: how frequent is the idiopathic form? An ultrasonographic study in a cohort of patients. Clin Exp Rheumatol28:63–672010
GagliardoAAvarinoCGiaimiGDi MatteoDMidiriMGagliardoC: Ultrasound combined with clinical neurophysiology in peripheral nerve pathologies: when it is worth? Preliminary data in 50 outpatients. Clin Neurophysiol124:e1892013. (Abstract)
GagliardoAAvarinoCGiaimiGDi MatteoDMidiriMGagliardoC: Emerging role of Ultrasound imaging associated to Clinical Neurophysiology as an advanced diagnostics of peripheral nerves pathologies. A Sicilian experience. Neuroradiology55:S1142013. (Abstract)
JarvikJGComstockBAHeagertyPJHaynorDRFulton-KehoeDKliotM: Magnetic resonance imaging compared with electrodiagnostic studies in patients with suspected carpal tunnel syndrome: predicting symptoms, function, and surgical benefit at 1 year. J Neurosurg108:541–5502008
MoranLPerezMEstebanABellonJArranzBdel CerroM: Sonographic measurement of cross-sectional area of the median nerve in the diagnosis of carpal tunnel syndrome: correlation with nerve conduction studies. J Clin Ultrasound37:125–1312009
NaranjoAOjedaSMendozaDFranciscoFQuevedoJCErausquinC: What is the diagnostic value of ultrasonography compared to physical evaluation in patients with idiopathic carpal tunnel syndrome?. Clin Exp Rheumatol25:853–8592007
PaduaLAprileIPazzagliaCFrascaGCaliandroPTonaliP: Contribution of ultrasound in a neurophysiological lab in diagnosing nerve impairment: A one-year systematic assessment. Clin Neurophysiol118:1410–14162007
SimonNGCageTNarvidJNossRChinCKliotM: High-resolution ultrasonography and diffusion tensor tractography map normal nerve fascicles in relation to schwannoma tissue prior to resection. J Neurosurg120:1113–11172014