title: Preoperative evaluation of peripheral nerve injuries: What is the place for ultrasound?
abstract: OBJECTIVE 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. METHODS 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. RESULTS 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%). CONCLUSIONS 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.
authors.affiliation: Plastic and Reconstructive Surgery, Department of Surgical, Oncological, and Oral Sciences, and.
authors.forename: Francesca
authors.initials: F
authors.lastname: Toia
authors.affiliation: "Clinical Course" Neurophysiology Unit, Palermo, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Gagliardo
authors.affiliation: Plastic and Reconstructive Surgery, Department of Surgical, Oncological, and Oral Sciences, and.
authors.forename: Salvatore
authors.initials: S
authors.lastname: D'Arpa
authors.affiliation: Section of Radiological Sciences, Department of Biopathology and Medical Biotechnologies, University of Palermo; and.
authors.forename: Cesare
authors.initials: C
authors.lastname: Gagliardo
authors.affiliation: "Clinical Course" Neurophysiology Unit, Palermo, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Gagliardo
authors.affiliation: Plastic and Reconstructive Surgery, Department of Surgical, Oncological, and Oral Sciences, and.
authors.forename: Adriana
authors.initials: A
authors.lastname: Cordova
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D059348:Peripheral Nerve Injuries / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000601:surgery; D010523:Peripheral Nervous System Diseases / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000601:surgery; D011300:Preoperative Care / Q000379:methods; D012189:Retrospective Studies; D014463:Ultrasonography
keywords: CMAP = compound muscle action potential; CSA = cross-sectional area; EMG = electromyography; LSD = least significant difference; MUAP = motor unit action potential; SNAP = sensory nerve action potential; electrodiagnosis; nerve imaging; nerve surgery; peripheral nerve; ultrasound